US20140069224A1 - Steering lock - Google Patents

Abstract

A steering lock for locking a rotary steering member against rotation. A lockbolt is movable along a first axis between steering member-locking and -unlocking positions. A shuttle moves between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position. An actuator drives the lockbolt to the steering member-locking position by moving the shuttle to the blocking position. An output gear is drivable by the actuator. A rotary drive member has a first portion formed with gear teeth meshed with the output gear, and a second portion formed with a driving structure engaged with a follower structure of the shuttle, whereby the shuttle is configured to translate axially toward and away from the first axis when the rotary drive member rotates in place.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims priority to U.S. Provisional Patent Application No. 61/698,197 filed Sep. 7, 2012 and to U.S. Provisional Patent Application No. 61/810,444 filed Apr. 10, 2013, the entire contents of both of which are incorporated by reference herein.
BACKGROUND
• The present invention relates to locking mechanisms for locking (i.e., preventing unauthorized rotation of) a rotary steering member such as a steering wheel, handlebar, etc. of a vehicle.
• Conventional steering column locks use an actuator mechanism to drive a locking pin into and out of locking engagement with a steering shaft. Efficient transfer of motion can be accomplished by directly driving the locking pin back and forth. However, certain circumstances may arise in which the locking pin becomes substantially wedged against one of the recesses in the steering shaft. In order to account for this occurrence, the electric motor that drives the locking pin and the corresponding electric drive circuit for the motor must have current/power ratings substantially higher than what is required for normal operation (when the locking pin is not wedged). Also, complex gear reduction devices may be implemented in order to multiply the torque output of the motor. In either case, the locking device as a whole becomes more costly and complicated, and may generate excessive noise.
SUMMARY
• In one construction, the invention provides a steering lock for selectively inhibiting rotation of a rotary steering member having a rib. The steering lock includes a lockbolt movable along a first axis between a steering member-locking position, in which a distal tip of the lockbolt is positioned in interference with the rib, and a steering member-unlocking position, in which the distal tip of the lockbolt is positioned out of interference with the rib. A shuttle is movable between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position to the steering member-unlocking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position. An actuator is coupled to the shuttle and operable to drive the lockbolt to the steering member-locking position by moving the shuttle from the non-blocking position to the blocking position. A lost motion connection is provided between the actuator and the lockbolt. Motive force from the actuator is transmitted through the lost motion connection to drive the lockbolt to the steering member-locking position when the rib is not aligned with the first axis, and motive force from the actuator is taken up by the lost motion connection when the rib is aligned with the first axis.
• In another construction, the invention provides a steering lock for selectively inhibiting rotation of a rotary steering member having a rib. The steering lock includes a lockbolt movable along a first axis between a steering member-locking position, in which a distal tip of the lockbolt is positioned in interference with the rib, and a steering member-unlocking position, in which the distal tip of the lockbolt is positioned out of interference with the rib. A shuttle is movable between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position to the steering member-unlocking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position. An actuator is coupled to the shuttle and operable to drive the lockbolt to the steering member-locking position by moving the shuttle from the non-blocking position to the blocking position. A lost motion connection is provided between the actuator and the lockbolt. The lost motion connection is configured to store energy supplied from the actuator when the shuttle from the non-blocking position to the blocking position while the rib is aligned with the first axis. The lockbolt is movable to the steering member-locking position by the stored energy of the lost motion connection when the rib is moved away from the first axis.
• In yet another construction, the invention provides a steering lock for selectively inhibiting rotation of a rotary steering member having a rib. The steering lock includes a lockbolt movable along a first axis between a steering member-locking position, in which a distal tip of the lockbolt is positioned in interference with the rib, and a steering member-unlocking position, in which the distal tip of the lockbolt is positioned out of interference with the rib. A shuttle is movable between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position to the steering member-unlocking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position. An actuator is coupled to the shuttle and operable to drive the lockbolt to the steering member-locking position by moving the shuttle from the non-blocking position to the blocking position. The lockbolt is unbiased along the first axis.
• In yet another construction, the invention provides a steering lock for selectively inhibiting rotation of a rotary steering member having a rib. The steering lock includes a lockbolt movable along a first axis between a steering member-locking position, in which a distal tip of the lockbolt is positioned in interference with the rib, and a steering member-unlocking position, in which the distal tip of the lockbolt is positioned out of interference with the rib. A shuttle moves between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position. An actuator is operatively coupled to the shuttle and operable to drive the lockbolt to the steering member-locking position by moving the shuttle from the non-blocking position to the blocking position. An output gear is drivable by the actuator. A rotary drive member has a first portion formed with gear teeth meshed with the output gear, and a second portion formed with a driving structure engaged with a follower structure of the shuttle, whereby the shuttle is configured to translate axially toward and away from the first axis when the rotary drive member is rotated in place. In some constructions, the driving structure of the rotary drive member includes a spiral cam (e.g., a spiral cam groove). In other constructions, the driving structure of the rotary drive member includes a threaded drive portion and the shuttle includes a threaded follower structure.
• Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a steering lock in a locked state.
• FIG. 2 is a perspective view of the steering lock ofFIG. 1 in an unlocked state.
• FIG. 3 is a perspective view of an actuation device of the steering lock ofFIG. 1.
• FIG. 4 is a second perspective view of the actuation device ofFIG. 3.
• FIG. 5 is a cross-sectional view of the steering lock, taken along line5-5 ofFIG. 1.
• FIG. 6 is a cross-sectional view of the steering lock, taken along line6-6 ofFIG. 2.
• FIG. 7 is a cross-sectional view of the steering lock ofFIG. 1 in a state in which a lockbolt is obstructed from reaching the locked state when actuated.
• FIG. 8 is a perspective view of a steering lock according to another construction in which the output shaft is offset from the actuator axis.
• FIG. 9 is a perspective view of a steering lock according to another construction in which a rotary shuttle is provided.
• FIG. 10 is a perspective view of the steering lock ofFIG. 9 in a locked state.
• FIG. 11 is a perspective view of the steering lock ofFIG. 9 in an unlocked state.
• FIG. 12 is a perspective view of the steering lock ofFIG. 9 in a state in which a lockbolt is obstructed from reaching the locked state when actuated.
• FIG. 13 is a perspective view of a steering lock according to another construction having a passive lockbolt.
• FIG. 14 is a partially exploded assembly view of the steering lock ofFIG. 13 in which the housing is removed from the actuation device.
• FIG. 15 is front view of the steering lock ofFIG. 13 in a locked state.
• FIG. 16 is a front view of the steering lock ofFIG. 13 in an unlocked state.
• FIG. 17 is a front view of the steering lock ofFIG. 13 in a state in which the lockbolt is obstructed from reaching the locked state when actuated.
• FIG. 18 is a cross-sectional view of a steering lock according to another construction.
• FIG. 19 is a detail cross-sectional view of a lockbolt and shuttle of the steering lock ofFIG. 18.
• FIG. 20 is a side view of an actuation mechanism of the steering lock ofFIG. 18, shown in the unlocked state.
• FIG. 21 is a side view of the actuation mechanism of the steering lock ofFIG. 18, shown in the locked state.
• FIG. 22 is a perspective view of an output shaft and crank of the actuation mechanism.
• FIG. 23 is a perspective view of a steering lock according to another construction.
• FIG. 24 is a perspective view of an actuation mechanism of the steering lock ofFIG. 23.
• FIG. 25 is a perspective view of a steering lock according to another construction.
• FIG. 26 is an alternate perspective view of the steering lock ofFIG. 25.
• FIG. 27 is a perspective view of the steering lock ofFIGS. 25-26 with a cover portion of the housing removed to illustrate the actuation mechanism therein.
• FIG. 28 is a perspective view identical toFIG. 27, but having a gearbox sub-housing removed to illustrate a gear train. The lockbolt is in the locked state.
• FIG. 29 is a perspective view identical toFIG. 28, but with the lockbolt in the unlocked state.
• FIG. 30 is a perspective view of the actuation mechanism of the steering lock ofFIGS. 25-29. The lockbolt is in the locked state, as inFIG. 28.
• FIG. 31 is an alternate perspective view of the actuation mechanism of the steering lock ofFIGS. 25-29. The lockbolt is in the locked state, as inFIGS. 28 and 30.
• FIG. 32 is a cross-sectional view of the steering lock ofFIGS. 25-29 in a state in which the lockbolt is in the unlocked state.
• FIG. 33 is a cross-sectional view of the steering lock ofFIGS. 25-29 in a state in which the lockbolt is in the locked state.
• FIG. 34 is a perspective view of a steering lock and actuation mechanism similar to that ofFIGS. 25-33, but having an alternate housing.
DETAILED DESCRIPTION
• Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
• FIGS. 1 and 2 illustrate asteering lock100 operable to selectively lock anadjacent steering member104 against rotation about its axis A. Thesteering lock100 includes ahousing108 that is mounted at a predetermined location proximate the steeringmember104. Acover112 is removably coupled to thehousing108 to enclose anactuation device116 of thesteering lock100. Theactuation device116, illustrated inFIGS. 3 and 4 and discussed in further detail below, includes alockbolt120 that is movable between a steering member-locking position or simply “locked” position (FIG. 1) and a steering member-unlocking position or simply “unlocked” position (FIG. 2). In the illustrated construction, thelockbolt120 is movable between the locked and unlocked positions along an axis B that is substantially perpendicular to the axis A of the steeringmember104.
• As shown in at leastFIGS. 1 and 2, the ring-shapedsteering member104 includes a plurality of notches orgrooves124 that are elongated parallel to the axis A. Each adjacent pair ofgrooves124 are separated by arib128. When thesteering lock100 is locked, thelockbolt120 is positioned within one of thegrooves124, and interference between thelockbolt120 and the twoadjacent ribs128 prevent substantial rotation of the steeringmember104 about the axis A. The size, shape, and number of thegrooves124 and theribs128 can be varied from the illustrated construction according to the needs of a particular application. Although limited rotation of the steeringmember104 may be possible in some circumstances when locked by thesteering lock100, the steering mechanism (e.g., steering wheel, handlebars, etc.) to which thesteering member104 is coupled is rendered unusable for normal operation of the vehicle on which thesteering lock100 is provided.
• As shown inFIGS. 3 and 4, theactuation device116 includes anactuator132 and ashuttle136 in addition to thelockbolt120. Theactuator132 of the illustrated construction is an electric motor, although other types of actuators may be used. As discussed in further detail below, in some constructions theactuator132 is an electric motor rated for less than 1.0 A of current at max load. In some constructions, theactuator132 is an electric motor rated for about 500 mA of current at max load. As shown inFIGS. 3 and 4, theactuator132 includes anoutput shaft140. In the illustrated construction, theoutput shaft140 is a lead screw rotatable about an axis C defined by theactuator132. The lead screw may have a pitch of about 10 teeth per inch.
• Although theoutput shaft140 is provided as a direct rotary drive member extending directly from theactuator132, theactuator132 may be coupled to theoutput shaft140 by a power transmission device such as a gear train having one or more gears that alter the torque and speed of theoutput shaft140. In such constructions, theoutput shaft140 may have an axis that is different from the axis of theactuator132, and may be linearly offset or angled relative thereto. Such an arrangement may not only provide a desired gear ratio but also a desired orientation of components (e.g., for more efficient packaging, etc.). For example,FIG. 8 illustrates asteering lock200 including anoutput shaft240 that is offset from theactuator232. Except as described herein, thesteering lock200 is otherwise substantially identical to thesteering lock100 ofFIGS. 1-7. As such, similar reference characters (with leading digits increased by 100) are used for similar parts where appropriate. Reference is made to the above description of thesteering lock100 for features and aspects of thesteering lock200 ofFIG. 8 not specifically described below.
• In thesteering lock200 ofFIG. 8, theoutput shaft240 is offset from the axis C2 of theactuator232. In the illustrated construction, theoutput shaft240 is parallel to the axis C2 of theactuator232 and is coupled to theactuator232 by a power transmission device (e.g., gear train). Although other offset arrangements are optional, theactuator232 includes ashaft239 provided with adrive gear241. Theoutput shaft240 is provided with a drivengear243 that is rotated by thedrive gear241 of theactuator232. The drivengear243 and theoutput shaft240 form a rotary drive member which is drivable by theactuator232 and is operable to drive theshuttle236. The available torque at theoutput shaft240 is increased and its angular velocity is decreased by driving it through the twogears241,243 instead of being driven directly by theshaft239 of theactuator232. Thus, the output shaft240 (which is configured as a lead screw in the illustrated construction) may be provided with fewer threads per inch than theoutput shaft140 of thesteering lock100 ofFIGS. 1-7. For example, theoutput shaft240 ofFIG. 8 may be provided with only about 4 teeth per inch. Thehousing208 is provided with a pair ofinternal cradles249 for rotatably supporting theoutput shaft240 on both sides of the drivengear243.
• Returning now to the construction illustrated inFIGS. 1-7, theshuttle136 is engaged with theoutput shaft140 to be moved between two positions by theactuator132. The first position of theshuttle136 is a blocking position (FIG. 3) in which theshuttle136 obstructs movement of thelockbolt120 from the locked position (FIG. 1) to the unlocked position (FIG. 2). The second position of theshuttle136 is a non-blocking position in which theshuttle136 does not obstruct movement of thelockbolt120 from the locked position (FIG. 1) to the unlocked position (FIG. 2). As described in further detail below, theshuttle136 is configured to move in a plane P that is substantially perpendicular to the lockbolt axis B.
• In some constructions, as shown inFIGS. 3-7, theshuttle136 includes acam roller144 and thelockbolt120 includes acam follower surface148. In the illustrated construction, thecam follower surface148 is opposite a tip orengagement end152 of thelockbolt120 which is engageable with the steeringmember104. Thecam follower surface148 includes afirst portion148A that is inclined relative to both the lockbolt axis B and the plane P in which the shuttle moves and asecond portion148B that is substantially perpendicular to the lockbolt axis B and parallel to the shuttle's plane of movement P. Movement of thecam roller144 along thecam follower surface148 occurs with rolling contact which limits the amount of friction that theactuator132 must overcome to move theshuttle136.
• Theshuttle136 further includes aguide body156, which supports and guides thecam roller144. In the illustrated construction, thecam roller144 is mounted on ashaft160 that extends through aslot164 formed in theguide body156. Theslot164 is elongated in a direction substantially perpendicular to the lockbolt axis B. Aspring168 of theshuttle136 biases theshaft160 and thecam roller144 to an end of theslot164 that is furthest away from theoutput shaft140 of theactuator132. In the illustrated construction, thespring168 is a torsion spring that can function as a lost motion device as described in further detail below.
• Theguide body156 of theshuttle136 includes a threadedaperture172 that is engaged with theoutput shaft140 of theactuator132 and coaxial with its axis C. In the illustrated construction, theoutput shaft140, which is a lead screw, rotates about the axis C and drives motion of the shuttle along the axis C (within the shuttle's plane of movement P). In other constructions, theoutput shaft140 of theactuator132 may be configured to move in and out of theactuator132 along the axis C such that theshuttle136 may be fixed relative to theoutput shaft140 and moved directly with theoutput shaft140. In yet other constructions, theactuator132 may be configured to rotate the shuttle136 (within the plane P) between the blocking position and the non-blocking position. Furthermore, a separate nut (not shown) may be provided rather than providing the threadedaperture172 directly in theguide body156. This not only allows different materials to be used for theguide body156 and the nut as desired, but also allows the establishment of a dynamic relationship between the nut and theguide body156. For example, the nut can be made slidable within theguide body156 so that, when theoutput shaft140 rotates, the nut travels relative to theguide body156 and achieves a running speed before contacting theguide body156. This reduces the starting load on theactuator132 and provides an impact-type actuation of theshuttle136, and specifically theguide body156.
• As shown inFIGS. 3 and 4, theshuttle136 includesauxiliary rollers176 mounted on theshaft160 of thecam roller144. Theauxiliary rollers176, theshaft160, and thecam roller144 constitute a roller unit of theshuttle136 that is movable relative to theguide body156. Theauxiliary rollers176 are guided by internal guide surfaces178 of thehousing108 and thecover112. The guide surfaces178 are flat so that the contact between theauxiliary rollers176 and the guide surfaces178 keep the movement of theshuttle136 within the desired plane P. Theauxiliary rollers176 provide a guiding function with rolling contact which limits the amount of friction that theactuator132 must overcome to move theshuttle136.
• As shown inFIGS. 5-7, thehousing108 includes aninternal recess180 in which thelockbolt120 is positioned. Theinternal recess180 is provided with a plurality of guide surfaces184 that guide movement of thelockbolt120 along the axis B. Aspring188 is positioned between respective abutment surfaces192,196 of thelockbolt120 and theinternal recess180. Thespring188 biases thelockbolt120 in a direction along the axis B that tends to retract thelockbolt120 into thehousing108 and away from the steeringmember104. In other words, thespring188 biases thelockbolt120 toward the unlocked position.
• In operation, thesteering lock100 is kept in the unlocked state (FIGS. 2 and 6) during normal operation of the vehicle. In this manner, the steeringmember104 can rotate freely about its axis A without obstruction from thelockbolt120. Upon being commanded by the operator or automatically by a predetermined function of the vehicle's security system, thesteering lock100 can be moved to the locked state (FIGS. 1 and 5).
• In order to move thesteering lock100 to the locked state, theactuator132 is powered. Powering theactuator132 may include supplying electrical current to an electric motor via an electrical circuit, but may alternately include supplying energy to theoutput shaft140 by mechanical or fluid means. When theoutput shaft140 is constructed as a lead screw, rotation of theoutput shaft140 drives theguide body156 to move parallel to the axis C of theactuator132. Thespring168 between theguide body156 and thecam roller144 is strong enough to transfer the motion from theguide body156 to thecam roller144 so that thecam roller144 rolls from the inclinedfirst portion148A of thecam follower surface148 to thesecond portion148B, thereby overcoming the bias of thelockbolt spring188 and moving thelockbolt120 to the locked position (FIG. 5).
• The above description of how theactuation device116 moves thelockbolt120 to the locked position assumes that thelockbolt120 is aligned with one of thenotches124 of the steeringmember104 and not one of theintermediate ribs128. However, there is a significant chance that, at the time that theactuator132 is powered to move thesteering lock100 from the unlocked state to the locked state, thelockbolt120 will be aligned with one of theribs128. This occurrence is illustrated inFIG. 7. In the event that thelockbolt120 is aligned with one of theribs128 when actuated, theactuator132 still actuates and moves theguide body156 of theshuttle136 just as it would if thelockbolt120 were aligned with one of thenotches124. However, the movement of thelockbolt120 is stopped prematurely when thetip152 contacts the top of therib128. As theactuator132 continues to move theguide body156, thespring168 acts as a lost motion device, storing energy while thecam roller144 remains in contact with the inclined camfollower surface portion148A. Theslot164 in theguide body156 allows theguide body156 to move relative to theshaft160 and thecam roller144. The lost motion device prevents an overloading of theactuator132 when thelockbolt120 contacts the top of arib128 and allows thelockbolt120 to later move to the locked position without further powering theactuator132. As soon as the steeringmember104 is moved slightly to remove the obstructingrib128 from the path of thelockbolt120, the energy stored in thespring168 is released, driving thecam roller144 to the second portion of thecam follower surface148B and simultaneously moving thelockbolt120 into the locked position.
• In some instances, one of theribs128 of the steeringmember104 may become wedged against thelockbolt120 when thelockbolt120 is in the locked position. For example, this may occur when one or more of the steerable wheels coupled to thesteering member104 are wedged against a stationary object, such as a curb. When a wedged condition exists and it is desired to move thesteering lock100 from the locked state to the unlocked state (thereby withdrawing thelockbolt120 from the steering member104), theactuator132 operates normally and one or more passive features assist in releasing thelockbolt120 from the wedged condition. Thesteering lock100 does not rely on the power supplied by theactuator132 to extract or “un-wedge” thelockbolt120. In fact, theactuator132 and theshuttle136 provide “push-only” actuation of thelockbolt120, and in some constructions, are not coupled in a manner that enables urging of thelockbolt120 toward the unlocked position by the power of theactuator132. Because theactuator132 is not designed to extract thelockbolt120 from a wedged condition, the power rating for theactuator132 can be kept low. This lends to lower cost of theactuator132 and associated running circuitry as well as generally smaller size and easier packaging.
• One passive feature that aids in releasing thelockbolt120 from a wedged condition is the taperedtip152 of thelockbolt120. When locked, twotapered surfaces152A of thetip152 interfere with and potentially contact the steeringmember ribs128 are tapered by an angle α. from the adjacent flat sides of thelockbolt120. Because the adjacent flat sides of thelockbolt120 are substantially parallel with the lockbolt axis B, the same angle α is made between thetapered surfaces152A and the lockbolt axis B. From the wedged condition, rotation of the steeringmember104 causes the side of one of theribs128 to contact one of thetapered surfaces152A of thetip152. Thus, torque from the steeringmember104 generates a camming reaction along axis B that urges the release of thelockbolt120 from the wedged condition with the steeringmember104. In some constructions, the angle α is between about 10 degrees and about 20 degrees. When the angle α is made too high, torque from the steeringmember104 is transmitted to a large degree along the axis B of thelockbolt120. These large forces must be borne by theactuation device116 to keep thelockbolt120 in the locked position. Thus, the structural demands on theshuttle136, theoutput shaft140, etc. are higher. On the other hand, when the angle α is made too small, a very large torque from the steeringmember104 is required to produce a camming force (along axis B) sufficient to release thelockbolt120 from the wedged condition. In certain constructions, such as the illustrated construction, an angle α between about 12 degrees and about 16 degrees may provide an advantageous balance of these design considerations.
• Another passive feature that aids in releasing thelockbolt120 from a wedged condition is thespring188, which is compressed from its at-rest state when thelockbolt120 is in the locked position. Therefore, thespring188 stores energy that urges thelockbolt120 to the unlocked position whenever thelockbolt120 is in the locked condition, including when in a wedged condition.
• As mentioned above, the operation of theactuator132 is not affected whatsoever by the existence of a wedged condition. Theactuator132 operates to draw theshuttle136 and thus thecam roller144 out of the blocking position ofFIG. 5 and toward the non-blocking position ofFIG. 6. However, movement of theshuttle136 does not directly cause movement of thelockbolt120 to the unlocked position. Once theshuttle136 and thecam roller144 are moved out of the way, the taperedtip152 and thespring188 work together to drive thelockbolt120 from the wedged condition without active pulling or powered extraction via theactuator132 or any other powered device acting on thelockbolt120.
• FIGS. 9-12 illustrate asteering lock300 according to yet another construction. Thesteering lock300 ofFIGS. 9-12 is similar in many aspects to thesteering lock100 ofFIGS. 1-7. Reference characters, with leading digits incremented by 100, are re-used where appropriate for consistency. Reference is made to the above description of thesteering lock100 for features and aspects of thesteering lock300 ofFIGS. 9-12 not specifically described below.
• FIG. 9 illustrates thesteering lock300 without the cover of thehousing308, andFIGS. 10-12 illustrate thesteering lock300 without thehousing308 at all so that theactuation device316 can be seen clearly. As with thesteering lock100, thesteering lock300 ofFIGS. 9-12 includes alockbolt320 that is movable between a steering member-locking position or simply “locked” position (FIG. 10) and a steering member-unlocking position or simply “unlocked” position (FIG. 11). In the illustrated construction, thelockbolt320 is movable between the locked and unlocked positions along an axis B3 that is substantially perpendicular to the axis A3 of the steeringmember304.
• Theactuator332 of thesteering lock300 includes anoutput shaft340 provided with adrive gear341. Theoutput shaft340 and thedrive gear341 define an axis C3. Theshuttle336 is driven back and forth between blocking and non-blocking positions by thedrive gear341. In the illustrated construction, a plurality ofintermediate gears343 are positioned between thedrive gear341 and a set ofgear teeth345 on theguide body356 of theshuttle336. Theintermediate gears343 provide a reduction in angular velocity and an increase in torque from theoutput shaft340. Theintermediate gears343 serve as rotary drive members that are drivable by theactuator332 and operable to drive theshuttle336, which in the illustrated construction is also rotatable or pivotable.
• Theguide body356 pivots within the housing and moves in a plane P3 that is perpendicular with the axis C3 of theoutput shaft340 and parallel to the axis B3 of thelockbolt320. In some constructions, theguide body356 andactuator332 have alternate orientations. For example, theguide body356 andactuator332 may be configured to be turned 90 degrees so that the axis C3 of theoutput shaft340 is parallel to the axis B3 of thelockbolt320 and theguide body356 moves in a plane that is perpendicular to the axis B3 of thelockbolt320. Thehousing308 includes at least one internal guide surface (not shown) similar to those of thehousing108 for guiding movement of theguide body356, however the guide surface is arc-shaped to guide the pivoting movement of theguide body356.
• In addition to theguide body356, theshuttle336 includes acam roller344 andauxiliary rollers376. Thecam roller344 is mounted on ashaft360 that is received in an arc-shapedslot364 in theguide body356. Thecam roller344 contacts an arc-shapedcam follower surface348 to selectively actuate thelockbolt320 from the unlocked position to the locked position. Similar to theactuation device116 described above, theactuator332 and theshuttle336 are only operable to actuate thelockbolt320 to the locked position and block thelockbolt320 from returning to the unlocked position, and are not configured to actively retract thelockbolt320 from the locked position.
• Unlike theshuttle136 ofFIGS. 1-7 in which theshaft160 simply slides back and forth in theslot164 to allow movement of thecam roller144 relative to theguide body156, theshaft360 on which thecam roller344 of the steering lock ofFIGS. 9-12 is supported by apivot arm375 that is coupled to theguide body356 with apivot shaft377.
• Similar to theshuttle136 described above, theshuttle336 includes aspring368 that biases theshaft360 and thecam roller344 to one end of theslot364. In the illustrated construction, thespring368 is a torsion spring that can function as a lost motion device when, at the time that theactuator332 is powered to move thelockbolt320 from the unlocked position to the locked position, thelockbolt320 is aligned with one of theribs328 on the steeringmember304. When this occurs, thespring368 stores energy as theguide body356 moves to the blocking position and thecam roller344 remains in the non-blocking position. Theslot364 in theguide body356 allows theguide body356 to move relative to theshaft360 and thecam roller344. The lost motion device prevents an overloading of theactuator332 when thelockbolt320 contacts arib328. As soon as the steeringmember304 is moved slightly to remove the obstructingrib328 from the path of thelockbolt320, the energy stored in thespring368 is released so that thecam roller344 drives thelockbolt320 into the locked position and blocks it from retraction to the unlocked position.
• FIGS. 13-17 illustrate asteering lock400 according to yet another construction. Thesteering lock400 ofFIGS. 13-17 is similar in some aspects to the steering locks100,200,300 ofFIGS. 1-12. Reference characters, with leading digits incremented by 100, are re-used where appropriate for consistency. Reference is made to the above description of the steering locks100,200,300 for features and aspects of thesteering lock400 ofFIGS. 13-17 not specifically described below.
• As shown inFIGS. 13 and 14, thehousing408 includes first andsecond housing portions408A,408B, which in the illustrated construction, are configured as housing halves. The first andsecond housing portions408A,408B are of complementary shape and are coupled together byfasteners409, which may include threaded fasteners such as the two illustrated screws that are located at overlapping areas of the twohousing portions408A,408B. Similar to the steering locks described above, thehousing408 is configured to be mounted at a predetermined location proximate asteering member404, and anactuation device416 of thesteering lock400 is configured to selectively move alockbolt420 out of thehousing408 from a steering member-unlocking position or simply “unlocked” position (FIG. 16) to a steering member-locking position or simply “locked” position (FIG. 15). In the illustrated construction, thelockbolt420 is movable between the locked and unlocked positions along an axis B4 that is substantially perpendicular to the axis A4 of the steeringmember404.
• In one construction, the steeringmember404 is substantially identical to the ring-shapedsteering members104,204,304 described above and includes a plurality of notches orgrooves424 that are elongated parallel to the axis A4, with each adjacent pair ofgrooves424 being separated by arib428. When thesteering lock400 is locked, thelockbolt420 is positioned within one of thegrooves424, and interference between thelockbolt420 and the twoadjacent ribs428 prevents substantial rotation of the steeringmember404 about the axis A4. The size, shape, and number of thegrooves424 and theribs428 can be varied from the illustrated construction according to the needs of a particular application. It should also be appreciated that theactuation device416 of thesteering lock400, and any of the others described above, may engage virtually any type of steering member to selectively inhibit the use thereof. For example, the steering member in some constructions may not be tubular or ring-shaped with outwardly-projecting ribs, and may instead have a projection-free outer surface that provides one or more lockbolt-receiving grooves in the form of one or more apertures. One or more ribs for interfering with thelockbolt420 in such a construction may simply be provided by the material adjacent the aperture(s).
• As shown inFIG. 14, each of thehousing portions408A,408B is configured to receive and support theactuation device416. A combined actuator mounting plate and printed circuit board (PCB)411 is jointly received by bothhousing portions408A,408B, with theedges411A of the mounting plate/PCB411 being received bychannels413 provided on the interior of thehousing portions408A,408B. Two actuator mounts415 are secured to the mounting plate/PCB411 and support opposing ends of theactuator432. Anadditional support417, which may be a bearing support received by thesecond housing portion408B, is provided on the end of theoutput shaft440. In some constructions, thePCB411 may not be configured as a mounting plate for theactuator432. In such constructions, theactuator432 may be electrically coupled with thePCB411 while being positioned by and/or mounted to at least one of thehousing portions408A,408B.
• Turning now to the mechanics of theactuation device416, certain aspects are generally similar to aspects already described with respect to at least one of the steering locks100,200,300 described above. For example, theactuation device416 utilizes ashuttle436 to deploy thelockbolt420 to the locked position. The shuttle is movable between a blocking position that obstructs movement of thelockbolt420 to the steering member-unlocking position and a non-blocking position that does not obstruct movement of thelockbolt420 to the steering member-unlocking position. Furthermore, a lost motion device is provided to store the actuation energy as described above when thelockbolt420 is actuated to move from the unlocked position to the locked position, but is blocked from immediately achieving the locked position. However, unlike the steering locks100,200,300 described above, thelockbolt420 of thesteering lock400 is completely passive, as no bias member is provided to urge thelockbolt420 along the lockbolt axis B4 to one position or the other. The specific construction and operation of theactuation device416 are explained in detail below.
• Theactuator432, which may be an electric motor rated for less than 1.0 amp at maximum load and in some constructions about 500 mA at maximum load, is coupled to theoutput shaft440 to rotate theoutput shaft440 about the axis C4. In the illustrated construction, theoutput shaft440 is constructed as a worm gear that is in meshed engagement with agear portion443A of a rotary drive member or crank443. Thegear portion443A forms a driven portion of thecrank443, and a drivingportion443B is rotationally coupled and axially offset from thegear portion443A. Thecrank443 is configured to rotate about an axis D4 when theoutput shaft440 is rotated by theactuator432. As shown inFIG. 14, a pair ofcradles445 are formed in thefirst housing portion408A for supporting thecrank443.
• Theshuttle436 is coupled to the crank443 and configured to apply an actuating force to thelockbolt420. Theshuttle436 includes a guide body or link456 coupled to the crank443 at apivot457, and a roller unit coupled to thelink456 through a lost motion device. In the illustrated construction, the roller unit includes a pair ofroller bearings476 mounted on acommon axle460, and the lost motion device includes a biasing member such as acoil spring468 positioned in an opening or slot464 of thelink456. As seen in the drawings, a first end of thecoil spring468 may abut afirst end464A of theslot464 and be retained on apost459 of thelink456, and the opposing end of thecoil spring468 may abut theaxle460 so that the roller unit is normally kept at a second opposite end of theslot464. Although one construction of the roller unit is shown, it should be appreciated that many alternate constructions will be apparent to those of skill in the art for providing a rolling interface between theshuttle436 and thelockbolt420.
• The roller unit is operatively coupled with thelockbolt420 through alockbolt carrier421. Thelockbolt carrier421 includes acentral recess461 that receives a portion of thelink456. Theaxle460 of the roller unit extends through a pair of matchingcam slots448 in thelockbolt carrier421 and through theslot464 in thelink456, thereby coupling thelink456 with thelockbolt carrier421. Thelockbolt420 is coupled with thelockbolt carrier421 by engagement between aprotrusion420A of thelockbolt420 and anaperture421A in thelockbolt carrier421 that enables thelockbolt420 and thelockbolt carrier421 to move together unitarily along the lockbolt axis B4. Although provided as separate components in the illustrated construction, thelockbolt420 and thelockbolt carrier421 constitute a lockbolt unit and may be replaced in some constructions of thesteering lock400 by a lockbolt unit of alternate construction, such as a one-piece lockbolt that is directly coupled to theshuttle436.
• Both theroller bearings476 of the roller unit and thelockbolt carrier421 are guided for linear movement by internal features of thehousing408. Portions of thelockbolt carrier421 contact a pair of guide surfaces484 (FIG. 14) on the inside of thefirst housing portion408A so that thelockbolt carrier421 is moved parallel to the lockbolt axis B4 when actuated by theshuttle436. Furthermore, guide surfaces478A,478B on both the first andsecond housing portions408A,408B constrain the movement of the roller unit to a plane P4 that is substantially perpendicular to the lockbolt axis B4. Thus, the roller unit moves perpendicular to the lockbolt axis B4 although thelink456 has the freedom to assume various angular orientations during movement of thecrank443. Because theaxle460 is supported at both its ends by theroller bearings476, theaxle460 experiences low friction rolling along the surfaces of thecam slots448 in thelockbolt carrier421 rather than sliding. Likewise, the outer portions of theroller bearings476 experience low friction rolling along either pair of the guide surfaces478A,478B rather than sliding.
• The operation and various states of thesteering lock400 are described with primary reference toFIGS. 15-17. InFIG. 15, thesteering lock400 is in a locked state, which is to say that thelockbolt420 is extended along the axis B4 to its locked position so that it is received in one of thegrooves424 of the steeringmember404 and rotation of the steeringmember404 is inhibited. The roller unit of theshuttle436 is positioned onsurfaces448B of thecam slots448 that extend substantially perpendicular to the lockbolt axis B4 to serve as blocking surfaces so that theshuttle436 blocks or physically obstructs the movement of thelockbolt420 from the locked position toward the unlocked position ofFIG. 16. In the illustrated construction, the blocking surfaces448B, while extending substantially perpendicular to the lockbolt axis B4, are positioned along the lockbolt axis B4 to intersect with the lockbolt axis B4. Any force applied from the steeringmember404 to thelockbolt420 in the unlocking direction is reacted against simply by contact between theroller bearings476 and the guide surfaces478B of thesecond housing portion408B, which are substantially perpendicular to the lockbolt axis B4. Such a force from the steeringmember404 is unable to backdrive theshuttle436 or theactuator432, so that thelockbolt420 passively but reliably stays in the locked position. No bias force along the lockbolt axis B4 is applied to thelockbolt420 in the locked position, and no energy or resistance from theactuator432 is used to keep thelockbolt420 in the locked position.
• To unlock thesteering lock400 and release the steeringmember404, theshuttle436 is moved from the blocking position to the non-blocking position. Theactuator432 is energized to rotate theoutput shaft440, which rotates the crank443 (counter-clockwise as viewed inFIGS. 15-17) to move thelink456. Thelink456 is moved so as to pull the roller unit, and particularly theaxle460, off of the blocking surfaces448B and into portions of thecam slots448 that are inclined with respect to the lockbolt axis B4 to provide inclined cam surfaces448A. In the illustrated construction, the cam surfaces448A of eachcam slot448 are oriented at approximately 45 degrees with respect to the lockbolt axis B4. When the roller unit is pulled by thelink456 away from the blockingsurfaces448B (to the right inFIGS. 15-17), the contact between theaxle460 and theinclined cam surfaces448A urges thelockbolt carrier421 and thelockbolt420 toward the unlocked position ofFIG. 16. Although the power of theactuator432 is applied in a manner to move thelockbolt420 from the locked position to the unlocked position, thelockbolt420 is substantially self-releasing due to the configuration of the taperedtip452, which is similar to thetip152 described above. Thus, even if a strong force is applied to thelockbolt420 by the steeringmember404, this force tends to automatically release thelockbolt420 from the steeringmember404 rather than wedging thelockbolt420 and holding it in the locked position against the power of theactuator432. Therefore, theactuator432 does not need a high power rating to cope with the extraction of a wedged lockbolt condition.
• Movement into the unlocked position is completed when the roller unit reaches a position in thecam slots448 that is opposite the blocking surfaces448B as shown inFIG. 16. This position defines the non-blocking position of theshuttle436. In the illustrated construction, thecrank443 positions theshuttle436 as remotely as possible from the lockbolt axis B4 in the non-blocking position. Thecoil spring468 or other lost motion device holds no residual or potential energy in the unlocked position, and thelockbolt420 is not subject to any other bias force in the unlocked position such that theactuator432 can simply be turned off and thelockbolt420 sits passively in the unlocked position until actuated to lock again. Theactuator432 is automatically stopped upon achieving the unlocked position ofFIG. 16. In one construction, a magnetic switch on the mounting plate/PCB411 may sense the orientation of thecrank443 by sensing a magnet or magnetic portion of thecrank443 to signal theactuator432 to turn off. Excessive travel of thecrank443 is also blocked by interference between aprotrusion447 on the drivingportion443B of thecrank443 and anabutment449 on the inside of thefirst housing portion408A.
• In order to lock thesteering lock400 and restrict movement of the steeringmember404, theactuator432 is energized to rotate theoutput shaft440, which rotates the crank443 (clockwise as viewed inFIGS. 15-17) to move thelink456. Thelink456 is moved so as to push the roller unit, and particularly to push theaxle460 via thecoil spring468 or other lost motion device, along the inclined cam surfaces448A toward the blocking surfaces448B. Because the roller unit is constrained to move within the plane P4, the movement of the roller unit toward the blocking surfaces448B (to the left as viewed inFIGS. 15-17), causes thelockbolt carrier421 and thelockbolt420 to move along the axis B4 toward the steeringmember404. Theactuator432 is automatically stopped upon actuating thecrank443 an amount corresponding to that required for actuating thelockbolt420 to the locked position via theshuttle436. Various types of open-loop or closed-loop controls may be used to control on/off operation of theactuator432. In some constructions, a magnetic switch on the mounting plate/PCB411 may sense the orientation of thecrank443 by sensing a magnet or magnetic portion of thecrank443 to signal theactuator432 to turn off. As shown inFIG. 15, thecrank443 may be rotated just past a top dead center position (in which thelink456 and thecoil spring468 intersect with the crank axis D4) so that any residual or potential energy stored in thespring468 in the locked position urges thecrank443 to rotate further clockwise. Excessive travel of thecrank443 in this direction is blocked by interference between theprotrusion447 on the drivingportion443B of thecrank443 and theabutment449 on the inside of thefirst housing portion408A. Thus, the locked position is stable without continued energisation of theactuator432, and although a slight bias force may exist within the shuttle436 (e.g., in thespring468 or other lost motion device between thelink456 and the roller unit), thelockbolt420 and thelockbolt carrier421 are not biased in either direction along the lockbolt axis B4 when in the locked position. Although illustrated inFIG. 15 as rotating slightly past top dead center, thecrank443 may stop substantially at top dead center to provide a stable locked position that is resistant to backdriving by thelink456.
• The above description of locking the steeringmember404 by moving thelockbolt420 to the locked position assumes that thelockbolt420 is aligned with agroove424 of the steeringmember404 when actuated. As such, the lost motion device transfers the actuating energy from the actuator to the roller unit and to thelockbolt420, substantially without absorbing such energy. However, it may not always be the case that thelockbolt420 is aligned with agroove424 of the steeringmember404 when actuated. Similar to the steering locks100,200,300 described above, theshuttle436 of thesteering lock400 ofFIGS. 13-17 is configured to store energy supplied by theactuator432 when theshuttle436 is actuated to move thelockbolt420 and thelockbolt420 abuts arib428 of the steeringmember404. When these circumstances arise in the illustrated construction, theactuator432 moves the guide body orlink portion456 of theshuttle436 to the position corresponding to the lockbolt-blocking position, but the roller unit does not achieve the blocking position. Instead, thecoil spring468 is compressed between theaxle460 of the roller unit and theend464A of theslot464 as shown inFIG. 17. The energy supplied by theactuator432 is stored by thecoil spring468, and theactuator432 is turned off. Although shown in the top dead center position inFIG. 17, thelink456 may be rotated slightly past top dead center (further clockwise as viewed inFIGS. 15-17) as described above with respect to the normal locking position. Because thecrank443 and thelink456 are stable in this position and do not need to be actively maintained by theactuator432, thesteering lock400 can remain in this imminent-lock position without any significant power draw (i.e., no power to theactuator432, and only nominal power to the associated circuit which may be used to maintain active sensors or the like) and without reaching a fault condition. From the state shown inFIG. 17, thelockbolt420 will move to the locked position by the energy stored in the lost motion device as soon as the steeringmember404 is moved to align agroove424 with thelockbolt420.
• FIGS. 18-22 illustrate asteering lock500 according to yet another construction. Thesteering lock500 ofFIGS. 18-22 is similar in some aspects to the steering locks100,200,300,400 ofFIGS. 1-17. Reference characters, with leading digits incremented by 100, are re-used where appropriate for consistency. Reference is made to the above description of the steering locks100,200,300,400 for features and aspects of thesteering lock500 ofFIGS. 18-22 not specifically described below.
• As shown inFIGS. 18 and 19, ahousing508 encloses anactuation device516 for actuating alockbolt520. Although only a portion of thehousing508 is shown, it should be understood that thehousing508 can include first and second portions similar to housings shown in other figures and described above. Similar to the steering locks described above, thehousing508 is configured to be mounted at a predetermined location proximate a steering member (not shown), and theactuation device516 of thesteering lock500 is configured to selectively move thelockbolt520 out of thehousing508 from a steering member-unlocking position or simply “unlocked” position (FIG. 20) to a steering member-locking position or simply “locked” position (FIGS. 18,19, and21). In the illustrated construction, thelockbolt520 is movable between the locked and unlocked positions along an axis B5 that is substantially perpendicular to an axis of the steering member.
• Turning now to the mechanical construction of theactuation device516, certain aspects are generally similar to aspects already described with respect to at least one of the steering locks100,200,300,400 described above. For example, theactuation device516 utilizes ashuttle536 to deploy thelockbolt520 to the locked position. Theshuttle536 is movable between a blocking position that obstructs movement of thelockbolt520 to the steering member-unlocking position and a non-blocking position that does not obstruct movement of thelockbolt520 to the steering member-unlocking position. Furthermore, a lost motion device is provided to store the actuation energy when thelockbolt520 is actuated to move from the unlocked position to the locked position, but is blocked (e.g., when aligned with a rib of the steering member rather than a groove) from immediately achieving the locked position. Similar to thesteering lock400, thesteering lock500 is completely passive, as no bias member is provided to urge thelockbolt520 along the lockbolt axis B5 to one position or the other. The specific construction and operation of theactuation device516 are explained in detail below.
• Theactuator532, which may be an electric motor, is coupled to theoutput shaft540 to rotate theoutput shaft540 about the axis C5. In the illustrated construction, theoutput shaft540 is constructed as a worm gear that drives a crank orrotary drive member543, e.g., via a meshing engagement with agear portion543A at the outer periphery of therotary drive member543, such that therotary drive member543 is drivable by theactuator532. Therotary drive member543 also includes a drivingportion543B radially inward of thegear portion543A. Therotary drive member543 is configured to rotate about an axis D5 when theoutput shaft540 is rotated by theactuator532. Unlike thecrank443 of thesteering lock400, the axis D5 is substantially parallel to the lockbolt axis B5 such that therotary drive member543 rotates in a plane P5 that is substantially perpendicular to the lockbolt axis B5. However, therotary drive member543 can have another orientation relative to the lockbolt axis B5, for example, similar to the crank443 andlockbolt420 if desired. A pin oraxle544 rotatably supports therotary drive member543 relative to thehousing508. As described further below, the drivingportion543B of therotary drive member543 is a cam.
• Theshuttle536 is coupled to therotary drive member543 and configured to apply an actuating force to thelockbolt520. Theshuttle536 includes a guide body or link556 coupled to therotary drive member543 via afollower557 and a lockbolt actuator coupled to thelink556 through a lost motion device. Although not illustrated in detail, the lockbolt actuator can be a roller unit similar to that described above with respect to thesteering lock400. The lockbolt actuator can include a pin oraxle560, and the lost motion device includes a biasing member such as acoil spring568 positioned in an opening or slot564 of thelink556. As seen in the drawings, a first end of thecoil spring568 may abut afirst end564A of theslot564, and the opposing end of thecoil spring568 may abut theaxle560 so that thepin560 is normally kept at a second opposite end of theslot564. Although illustrated schematically inFIGS. 20 and 21, it should be appreciated that thespring568 may be constructed and retained similar to that of thesteering lock400.
• A portion of thelink556 having theslot564 is substantially co-planar with therotary drive member543, and theaxle560 is constrained by thehousing508 to travel linearly within a plane, which is parallel to or the same as the plane P5 in which therotary drive member543 rotates. Thelink556 is provided with an offsetportion556A carrying thefollower557 as shown inFIGS. 20 and 21 to engage thecam driving portion543B of therotary drive member543. Thecam driving portion543B of therotary drive member543 is provided as a spiral cam (e.g.,spiral cam groove587 bounded by inner andouter walls589A,589B as shown inFIG. 22). Thespiral cam groove587 can include several distinct segments as shown. Afirst segment587A is provided as a radially outermost portion and is a substantially uniform radius dwell segment, the passage of which causes substantially no actuation of thefollower557 and thus, no movement of theshuttle536. Extending from thefirst segment587A in the counter-clockwise direction inFIG. 22 is asecond segment587B, which is a spiral segment of substantially uniformly-decreasing radius. Thesecond segment587B forms a majority of thegroove587, the passage of which causes substantially fixed-speed translation of thefollower557 and theshuttle536. Extending from thesecond segment587B in the counter-clockwise direction inFIG. 22 is athird segment587C. Thethird segment587C extends further radially inward over a short angular length to provide a more drastic movement of thefollower557 and the shuttle536 (e.g., faster movement, assuming equivalent angular velocity of the rotary drive member543). The furthest radiallyinward segment587D is a fourth segment provided as a dwell segment with substantially uniform radius.
• Theshuttle536 is operatively coupled with thelockbolt520 through alockbolt carrier521 similar to the above description of thesteering lock400. Thelockbolt520 and thelockbolt carrier521 are secured to move unitarily together. Although provided as separate components in the illustrated construction, thelockbolt520 and thelockbolt carrier521 constitute a lockbolt unit and may be replaced in some constructions of thesteering lock500 by a lockbolt unit of alternate construction, such as a one-piece lockbolt that is directly coupled to theshuttle536. Theaxle560 in theslot564 in thelink556 extends through a cam slot(s)548 in thelockbolt carrier521, thereby coupling thelink556 with thelockbolt carrier521.
• Unlike thelink456 of thesteering lock400 which has the freedom to assume various angular orientations during movement of the actuating crank443, the link556 (and thus, theshuttle536 as a whole) is guided for linear movement relative to thehousing508. Thelockbolt carrier521 is also guided for linear movement by internal features of thehousing508 such that thelockbolt carrier521 is moved parallel to the lockbolt axis B5 when actuated by theshuttle536.
• The operation and various states of thesteering lock500 are described with primary reference toFIGS. 19-21. InFIGS. 19 and 21, thesteering lock500 is in a locked state, which is to say that thelockbolt520 is extended along the axis B5 to its locked position so that it is received in one of the grooves of the steering member and rotation of the steering member is inhibited. Theaxle560 of theshuttle536 is positioned on surface(s)548B of the cam slot(s)548 that extend substantially perpendicular to the lockbolt axis B5 to serve as blocking surfaces so that theshuttle536 blocks or physically obstructs the movement of thelockbolt520 from the locked position toward the unlocked position ofFIG. 20. In the illustrated construction, the blocking surfaces548B are offset from the lockbolt axis B5 in the direction of theshuttle536 and therotary drive member543. Any force applied from the steering member to thelockbolt520 in the unlocking direction is reacted against simply by theaxle560 and corresponding supports within thehousing508, which are substantially perpendicular to the lockbolt axis B5. The reaction may also be borne by one or more roller bearings provided on theaxle560 to guide theaxle560 along the housing supports. Such a force from the steering member is unable to backdrive theshuttle536 or theactuator532, so that thelockbolt520 passively but reliably stays in the locked position. No bias force along the lockbolt axis B5 is applied to thelockbolt520 in the locked position, and no energy or resistance from theactuator532 is used to keep thelockbolt520 in the locked position. Thefollower557 is positioned within thefirst segment587A of thespiral cam groove587 when thesteering lock500 is in the locked state.
• To unlock thesteering lock500 and release the steering member, theshuttle536 is moved from the blocking position to the non-blocking position. In order to move theshuttle536, theactuator532 is energized to rotate theoutput shaft540, which rotates therotary drive member543 clockwise as shown inFIG. 22 so that thefollower557 enters thesecond segment587B of thespiral cam groove587. As therotary drive member543 rotates through the angle of thesecond segment587B, thefollower557 and thelink556 are driven linearly at a substantially fixed ratio with the angular rotation of thedrive member543. Thelink556 is moved so as to pull theaxle560 off of the blocking surface(s)548B and into portions of thecam slots548 that are inclined with respect to the lockbolt axis B5 to provide inclined cam surfaces548A (FIG. 19). In the illustrated construction, the cam surface(s)548A is oriented at approximately 45 degrees with respect to the lockbolt axis B5. When theaxle560 is pulled by thelink556 away from the blocking surface(s)548B, the contact between theaxle560 and theinclined cam surface548A urges thelockbolt carrier521 and thelockbolt520 toward the unlocked position. Although the power of theactuator532 is applied in a manner to move thelockbolt520 from the locked position to the unlocked position, thelockbolt520 is substantially self-releasing due to the configuration of the tapered tip552 (not visible in drawings—tapered in the direction into and out of the page as shown), which is similar to thetip152 described above. Thus, even if a strong force is applied to thelockbolt520 by the steering member, this force tends to automatically release thelockbolt520 from the steering member rather than wedging thelockbolt520 and holding it in the locked position against the power of theactuator532. Therefore, theactuator532 does not need a high power rating to cope with the extraction of a wedged lockbolt condition.
• Once thelockbolt520 is mostly or fully removed from engagement with the steering member, thefollower557 passes through thethird segment587C of thespiral cam groove587, by which thefollower557 is moved at an accelerated ratio with respect to the angular rotation of therotary drive member543. This enables thelockbolt520 to more quickly reach the unlocked position, when theactuator532 is substantially unloaded.
• Movement into the unlocked position is completed when thefollower557 passes into thefourth segment587D of thespiral cam groove587, which corresponds to theaxle560 reaching a position in the cam slot(s)548 that is opposite the blockingsurface548B as shown inFIG. 20. This position defines the non-blocking position of theshuttle536. In the illustrated construction, therotary drive member543 positions theshuttle536 as remotely as possible from the lockbolt axis B5 in the non-blocking position. Thecoil spring568 or other lost motion device holds no residual or potential energy in the unlocked position, and thelockbolt520 is not subject to any other bias force in the unlocked position such that theactuator532 can simply be turned off and thelockbolt520 sits passively in the unlocked position until actuated to lock again. Theactuator532 is automatically stopped upon achieving the unlocked position ofFIG. 20. In one construction, a magnetic switch may sense the orientation of therotary drive member543 by sensing amagnet543M or magnetic portion of the rotary drive member543 (FIG. 18) to signal theactuator532 to turn off.
• In order to lock thesteering lock500 and restrict movement of the steering member, theactuator532 is energized to rotate theoutput shaft540, which rotates therotary drive member543 to move thelink556. Thelink556 is moved so as to push theaxle560 via thecoil spring568 or other lost motion device, along the inclined cam surfaces548A toward the blockingsurface548B. Because theaxle560 is constrained to move within the plane P5, the movement of theaxle560 toward the blockingsurface548B (to the left as viewed inFIGS. 19-21), causes thelockbolt carrier521 and thelockbolt520 to move along the axis B5 toward the steering member. Theactuator532 is automatically stopped upon actuating therotary drive member543 an amount corresponding to that required for actuating thelockbolt520 to the locked position via theshuttle536. Various types of open-loop or closed-loop controls may be used to control on/off operation of theactuator532. In some constructions, a magnetic switch may sense the orientation of therotary drive member543 by sensing themagnet543M or magnetic portion of therotary drive member543 to signal theactuator532 to turn off.
• As theactuator532 is operated to rotate therotary drive member543 and lock thesteering lock500, thefollower557 is driven through thespiral cam groove587 from thefourth segment587D toward thefirst segment587A. This produces a sequence including a short dwell, a quick initial movement, a more gradual movement over a majority of the rotation, and a final dwell. Due to the constant radius of thefirst segment587A of thespiral cam groove587, as well as the engagement between thegear portion543A and theworm gear540, the locked position is stable without continued energisation of theactuator532. Although a slight bias force may exist within the shuttle536 (e.g., in thespring568 or other lost motion device between thelink556 and the axle560), thelockbolt520 and thelockbolt carrier521 are not biased in either direction along the lockbolt axis B5 when in the locked position.
• The above description of locking the steering member by moving thelockbolt520 to the locked position assumes that thelockbolt520 is aligned with a groove of the steering member when actuated. As such, the lost motion device transfers the actuating energy from the actuator to theaxle560 and to thelockbolt520, substantially without absorbing such energy. However, it may not always be the case that thelockbolt520 is aligned with a groove of the steering member when actuated, and in these instances, theshuttle536 operates similar to those described above to store energy supplied by theactuator532 when theshuttle536 is actuated to move thelockbolt520 and thelockbolt520 abuts a rib of the steering member. Therotary drive member543 is rotated to a position corresponding to the locked position, but theaxle560, thelockbolt carrier521, and thelockbolt520 are not moved. The energy supplied by theactuator532 is instead stored by thecoil spring568. Because therotary drive member543 and thelink556 are stable in this position and do not need to be actively maintained by theactuator532, thesteering lock500 can remain in this imminent-lock position without any significant power draw (i.e., no power supplied to theactuator532, and only nominal power to the associated circuit which may be used to maintain active sensors or the like) and without reaching a fault condition. From this state, thelockbolt520 will move to the locked position by the energy stored in the lost motion device as soon as the steering member is moved to align a groove with thelockbolt520.
• FIGS. 23 and 24 illustrate asteering lock600 andactuation device616 according to yet another construction. Thesteering lock600 ofFIG. 23, including theactuation device616 ofFIG. 24, is similar in some aspects to the steering locks100,200,300,400,500 ofFIGS. 1-22. Reference characters, with leading digits incremented by 100, are re-used where appropriate for consistency. Reference is made to the above description of the steering locks100,200,300,400,500 for features and aspects of thesteering lock600 andactuation device616 ofFIGS. 23 and 24 not specifically described below.
• Thesteering lock600 ofFIG. 23 features anactuation device616 as best shown inFIG. 24 that includes arotary drive member643 that is similar to therotary drive member543 shown inFIG. 22, and includes anouter gear portion643A and a radiallyinward driving portion643B provided as a spiral cam (e.g.,spiral cam groove687 bounded by inner andouter walls689A,689B). Thespiral cam groove687 includes several differently shapedportions687A-D, which can be similar to those of thecam groove587 and can function in a similar manner. Although therotary drive member643 generally actuates thelockbolt620 through ashuttle636 with a lost motion device (e.g., spring668), and with theshuttle636 being restrained (e.g., by corresponding guide features in the housing608) to move back and forth along a linear path similar to theshuttle536 ofFIGS. 18-21, theshuttle636 has a different construction than theshuttle536.
• Rather than the one-piece guide body or link556, the guide body or link is formed from twoseparate link members656A,656B slidably coupled together. The sliding interface can be defined as a male-female interface. In the illustrated construction, thefirst link member656A (closest to the rotary drive member643) forms a female component, and thesecond link member656B forms a male component. Thefirst link member656A includes a slot oropening664, and a portion of thesecond link member656B is positioned within theopening664 in thefirst link member656A. Thespring668 or other lost motion device is positioned substantially within theopening664 between the twolink members656A,656B to bias them to an extended-apart configuration as shown inFIG. 24. In the extended-apart configuration, thespring668 bears against afirst end664A of theopening664 and biases thesecond link member656B into abutting contact with an opposite end of theopening664. Either or both of thelink members656A,656B can include a spring retainer feature to maintain thespring668 in a desired position or orientation. Theaxle660 or other member movable into and out of blocking relationship with thelockbolt620 is fixed to thesecond link member656B to move directly therewith.
• Another difference between thesteering lock600 and thesteering lock500 ofFIGS. 18-22 is the orientation of theactuator632. As shown in the drawings, the axis C6 of the wormgear output shaft640 is substantially parallel with the linear path of theshuttle636, whereas the axis C5 is substantially skewed with respect to the linear path of theshuttle536. Both constructions represent viable solutions, and the optimum orientation of these and other components generally depends upon several factors that can include the desired gear ratio, the size of the actuator, and the size and shape of the available packaging space for the steering lock within a particular vehicle.
• FIGS. 25-33 illustrate asteering lock700 andactuation device716 according to yet another construction. Thesteering lock700, including theactuation device716 ofFIGS. 27-33, is similar in some aspects to the steering locks100,200,300,400,500,600 ofFIGS. 1-24. Reference characters, with leading digits incremented by 100, are re-used where appropriate for consistency. Reference is made to the above description of the steering locks100,200,300,400,500,600 for features and aspects of thesteering lock700 andactuation device716 ofFIGS. 25-33 not specifically described below.
• Thesteering lock700 ofFIG. 25 includes ahousing708 and acover712 which cooperates with thehousing708 to enclose anactuation device716 for controlling the state of thelockbolt720 for selectively locking a steering ring (not shown). Thehousing708 includes mountingportions710 at each of two opposing ends of thehousing708, one of which is adjacent thelockbolt720 and the other of which is remote from thelockbolt720. The two mountingportions710 are provided as generally cylindrical or tubular formations that are parallel to one another, and each extend across substantially the entire width of thehousing708. The axes of both of the mountingportions710 are substantially perpendicular to the lockbolt axis B7. One of the mounting portions710 (left inFIGS. 26-29) may be slightly elongated in a direction perpendicular to its axis (and perpendicular to the lockbolt axis B7) to allow for tolerancing when mounting thesteering lock700 to adjacent structure within a vehicle.
• Theactuation device716 includes anactuator732, which can be similar in many aspects to the actuators described above. For example, theactuator732 can be an electric motor having anoutput shaft740 defining an axis C7. However, theactuator732 of thesteering lock700 has a generally rectangular body shape having four generally flat sides. This can provide alternate mounting configurations and potentially quieter operation. Ashuttle736 having a similar function to the shuttles described above is drivable by theactuator732 between blocking and non-blocking positions. In view of the above description, a detailed description of the operation of theactuation device716 is not required for understanding, but it should be noted that theshuttle736 drives thelockbolt720 to the locked state by moving from the non-blocking position (retracted) to the blocking position (extended), and blocks thelockbolt720 from moving to the unlocked state when in the blocking position. Thus, thesteering lock700 can passively but positively retain thelockbolt720 in the locked state, and thelockbolt720 can be unbiased along the axis B7. Theshuttle736 also stores energy upon actuation to the blocking position when thelockbolt720 is aligned with a rib or projection of the steering ring. Theshuttle736 is driven by a parallel gear set including afirst gear741 on theoutput shaft740 and asecond gear743, which is larger in diameter than thefirst gear741. The first andsecond gears740,741 can be substantially enclosed by a sub-housing746. The sub-housing746 can include multiple pieces that fit together (e.g., snap-fit together) and generally conform to the shape of the first andsecond gears741,743. The sub-housing746 can provide an additional sound containment structure within thehousing708 so that noise from operation of thegears741,743 as measured outside the housing708 (e.g., within a vehicle cabin) is further reduced or eliminated.
• Thesecond gear743 includes threads engaged withthreads756T of theguide body756, so that theguide body756 is moved axially when thesecond gear743 is rotated in place. In the illustrated construction, the interior of thesecond gear743 is provided with female threads and thethreads756T on theguide body756 are external male threads, but other arrangements may be provided. Lost motion and energy storage are provided by theshuttle736 when theshuttle736 is actuated to the blocking position and thelockbolt720 is aligned with a rib of the steering ring rather than a groove. The lost motion device includes aspring768 positioned on apost portion759 of theguide body756, between atransverse flange portion756F and ashaft760. Theshaft760 is positioned within one ormore cam slots748 of thelockbolt carrier721, and also within aslot764 of theguide body756. The outer portions of theshaft760 are guided byslots778 or other surfaces of thehousing708. Thetransverse flange756F of theguide body756 is also guided for linear movement within thehousing708. A resilient bumper758 (FIGS. 32 and 33) may be provided within thehousing708 and configured to provide soft stops or limits to the motion of theguide body756. As illustrated, thebumper758 is a U-shaped member with two upstanding stops, one at either end. In other constructions, thebumper758 can have other shapes, or individual bumpers are provided for the fore and aft stops.
• Asensor magnet756M is coupled to theguide body756, and may be coupled to thetransverse flange756F. Themagnet756M can be held in a polymer body and snapped, clipped, threaded, bonded, or otherwise attached to thetransverse flange756F. In the illustrated construction, themagnet756M is positioned on a lateral side of thetransverse flange756F to move along a magnetic switch formed by twomagnetic sensors781 on thePCB711 positioned adjacent theactuation device716. Themagnetic sensors781 can be configured to sense the two limit positions of theguide body756 and provide feedback to a controller which controls operation of theactuator732. An additional sensor may be provided to directly sense the position of thelockbolt720. For example, anothermagnet720M (FIGS. 30 and 31) may be coupled to thelockbolt720 or thelockbolt carrier721 for detection by a magnetic sensor (not shown) coupled to thePCB711 adjacent thelockbolt720.
• FIG. 34 illustrates asteering lock800 similar to thesteering lock700 ofFIGS. 25-33, and in fact features thesame actuation device716. However, thesteering lock800 ofFIG. 34 includes ahousing808 having an alternate mounting interface than that of thehousing708. Instead of the cylindrical mountingportions710 that extend substantially perpendicular to the lockbolt axis B7, thehousing808 includes a plurality of individual mountingportions810 at each end, each provided as flanges with apertures that are substantially parallel with the lockbolt axis B7. The position and number of mountingportions810 may vary with different applications for different vehicle packaging constraints. Although not shown, thesteering lock800 includes a cover similar to thecover712 shown inFIGS. 25 and 26. Additional features and operation of thesteering lock800 are not described in detail herein as they will be understood from the preceding description.

Claims (26)

What is claimed is:

1. A steering lock for selectively inhibiting rotation of a rotary steering member having a rib, the steering lock comprising:

a lockbolt movable along a first axis between a steering member-locking position, in which a distal tip of the lockbolt is positioned in interference with the rib, and a steering member-unlocking position, in which the distal tip of the lockbolt is positioned out of interference with the rib;

a shuttle movable between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position to the steering member-unlocking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position;

an actuator operatively coupled to the shuttle and operable to drive the lockbolt to the steering member-locking position by moving the shuttle from the non-blocking position to the blocking position;

an output gear drivable by the actuator; and

a rotary drive member having a first portion formed with gear teeth meshed with the output gear, and further having a second portion formed with a driving structure engaged with a follower structure of the shuttle whereby the shuttle is configured to translate axially toward and away from the first axis when the rotary drive member is rotated in place.

2. The steering lock ofclaim 1, wherein the driving structure of the rotary drive member includes a spiral cam.

3. The steering lock ofclaim 2, wherein the spiral cam includes a spiral cam groove, and the follower structure of the shuttle is positioned within the spiral cam groove.

4. The steering lock ofclaim 2, wherein the spiral cam includes first and second constant radius dwell portions at radially inner and outer ends, and between the first and second dwell portions, further includes a majority portion having a radius decreasing substantially uniformly from the first dwell portion, and a minority portion having a more drastic radial decrease than the majority portion in a direction toward the second dwell portion.

5. The steering lock ofclaim 2, wherein the rotary drive member rotates about a second axis parallel to the first axis.

6. The steering lock ofclaim 2, further comprising a magnetic element coupled to the rotary drive member and at least one magnetic sensor positioned at a fixed location adjacent the rotary drive member.

7. The steering lock ofclaim 1, wherein the driving structure of the rotary drive member includes a threaded drive portion and the shuttle includes a threaded follower structure drivably coupled to the threaded drive portion of the rotary drive member.

8. The steering lock ofclaim 7, wherein the threaded drive portion of the rotary drive member is formed of an aperture with female threads and the threaded follower structure of the shuttle includes male threads.

9. The steering lock ofclaim 7, wherein the rotary drive member has an outer profile including gear teeth meshed with an output gear of the actuator, the steering lock further comprising a gear set sub-housing substantially enclosing the gear teeth of the rotary drive member and the output gear.

10. The steering lock ofclaim 7, wherein the shuttle includes a unitary guide body including the follower at a first end, a post portion with a slot at a second end for slidably receiving a lockbolt actuator, and a transverse flange between the first and second ends, the transverse flange having a first portion engaging a resilient bumper for defining first and second stops of the shuttle and a second portion receiving a magnetic element for position detection of the shuttle by at least one magnetic sensor positioned at a fixed location adjacent the shuttle.

11. The steering lock ofclaim 10, wherein two magnetic sensors are provided on a printed circuit board fixedly positioned within a housing of the steering lock that substantially encloses the actuator and the shuttle and partially encloses the lockbolt.

12. The steering lock ofclaim 1, wherein the shuttle is constrained to translate axially along a path that is substantially perpendicular to and intersecting with the first axis.

13. The steering lock ofclaim 1, further comprising a lost motion connection between the actuator and the lockbolt, wherein motive force from the actuator is transmitted through the lost motion connection to drive the lockbolt to the steering member-locking position when the rib is not aligned with the first axis, and wherein motive force from the actuator is taken up by the lost motion connection when the rib is aligned with the first axis.

14. The steering lock ofclaim 13, wherein the lost motion device includes a spring positioned between the follower of the shuttle and a lockbolt actuator portion of the shuttle.

15. The steering lock ofclaim 14, wherein the lockbolt actuator portion of the shuttle is constrained to move along a linear path that is perpendicular to the first axis.

16. The steering lock ofclaim 15, further comprising a housing enclosing the shuttle and the actuator and partially enclosing the lockbolt, wherein the lockbolt actuator portion of the shuttle is constrained to move along the linear path by at least one guide surface of the housing.

17. The steering lock ofclaim 14, wherein the lockbolt actuator portion includes a shaft extending through a slot formed in a post portion of the shuttle, the shaft being biased to one end of the slot by the spring, and wherein the spring is a coil spring encircling the post portion.

18. The steering lock ofclaim 14, wherein the shuttle includes first and second link members slidably coupled together, whereby one of the first and second link members is received in an opening of the other, and wherein the spring is positioned within the opening.

19. The steering lock ofclaim 1, further comprising a housing enclosing the shuttle and the actuator and partially enclosing the lockbolt, wherein the follower of the shuttle is constrained to move along a linear path by at least one guide surface of the housing.

20. The steering lock ofclaim 1, wherein a first inclined cam surface is provided between the shuttle and the lockbolt so that substantially linear movement of the shuttle to the blocking position in a direction substantially perpendicular to the first axis is configured to move the lockbolt to the steering member-locking position.

21. The steering lock ofclaim 20, wherein a second inclined cam surface is provided between the shuttle and the lockbolt so that substantially linear movement of the shuttle to the non-blocking position in a direction substantially perpendicular to the first axis is configured to move the lockbolt to the steering member-unlocking position.

22. The steering lock ofclaim 1, wherein the actuator is an electric motor.

23. The steering lock ofclaim 1, wherein the lockbolt is unbiased along the first axis.

24. The steering lock ofclaim 1, wherein the lockbolt is part of an integrally movable lockbolt unit that further includes a separately-formed lockbolt carrier.

25. The steering lock ofclaim 24, wherein the shuttle shares a cam interface with the lockbolt carrier for moving the lockbolt to at least one of the steering member-locking position and the steering member-unlocking position.

26. The steering lock ofclaim 1, wherein the second portion formed with the driving structure is positioned entirely within the first portion formed with the gear teeth.

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