US20140018816A1 - Torque transmitting ball joint driver having a rigid fixation mechanism - Google Patents

Abstract

An articulating driver having a ball-in-socket joint. The driver may include a driver tip having a spherical head, a retention cap having a domed surface to mate with the spherical head, an input shaft, a spring disposed in an end of the input shaft and in a recess of the retention cap opposite that of the domed surface, and a housing that receives the input shaft, the spring, the retention cap and the spherical head. The housing may have a tapered end to positionally retain the spherical head therein. In another aspect, the driver may include a driver tip coupled to the input shaft that includes an interface to engage a screw. A bushing may engage the driver tip at one end and receive the screw at the other end to retain the screw within the driver.

Description

BACKGROUND
• In procedures such as an anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (XLIF), cervical spine surgery, etc., when a disc space has been cleared out, a metal, polymer, or bone spacer is typically implanted between the two adjoining vertebrae. After these spacers or “cages” are inserted, surgeons often use metal screws, plates, and/or rods to further stabilize the spine. To insert the screws, a driver device having an articulating driver head may be used to deliver the screws to their spinal column and lock them into place.
• In such a driver device, a u-joint may be provided to allow the driver head to articulate with respect to an input shaft. However, the u-joint may have a range of angulation that makes it difficult for a user to maintain an appropriate force on a component (e.g., a screw) being driven. Further, in some drivers, a bushing within the driver head that retains a driver tip may wear out over time, which causes the driver tip to move around, thus making it difficult for the user to drive the component.
SUMMARY
• The present disclosure provides an articulating driver and for a ball-in-socket joint. The driver may include a driver tip having a spherical head, a retention cap having a domed surface to mate with the spherical head, an input shaft, a spring disposed in an end of the input shaft and in a recess of the retention cap opposite that of the domed surface, and a housing that receives the input shaft, the spring, the retention cap and the spherical head. The housing may have a tapered end to positionally retain the spherical head therein. In accordance with an aspect, the spherical head has a plurality of grooves defined in a surface thereof and the housing defines a plurality of holes. Each of the holes may receive a pin that passes through the housing and is received within a respective groove of the spherical head.
• In accordance with some implementations, there is provided a ball-in-socket joint that includes an input shaft, a output shaft having a spherical head, the spherical head having a plurality of grooves defined therein, a retention cap having a domed surface to mate with the spherical head, a spring disposed in an end of the input shaft and in a recess of the retention cap opposite that of the domed surface, and a housing that defines a plurality of holes and receives the input shaft, the spring, the retention cap and the spherical head, The housing may have a tapered end to positionally retain the spherical head therein. Each of the holes may receive a pin that passes through the housing and is received within a respective groove of the spherical head.
• In accordance with some implementations, there is provided a ball-in-socket joint that includes a housing that defines a plurality of holes, where the housing is tapered at one end. The ball-in-socket joint also may also include an input shaft, a spring disposed in an end of the input shaft that is disposed within the housing, a retention cap disposed with the house that receives the spring at one end and has a domed surface at the other end thereof, and an output shaft having a spherical head that is disposed within the housing. The ball shaped head may have defined therein a plurality of grooves within which pins inserted into the holes or inward protrusions cooperate to transmit torque from the input shaft to the output shaft.
• In accordance with some implementations, there is provided a driver having an input shaft adapted to transmit torque and a driver tip coupled to the input shaft. The driver tip may include an interface defined at an end thereof adapted to engage a screw. The driver may also include a bushing that engages the driver tip at one end and that receives the screw at the other end. The screw may be received within the bushing to engage the interface, and the input shaft is adapted to apply torque to the screw through the interface and to apply torque to the bushing by the engagement of the bushing with the driver tip.
• In accordance with some implementations, there is provided a method of engaging a screw with a driver having an input shaft, a bushing, and a driver tip. The method may include engaging the bushing with the driver tip; advancing the bushing along a longitudinal axis of the driver tip in a first direction to expose a screw interface; receiving the screw at the screw interface; and moving the bushing in a second direction along the longitudinal axis to couple a head of the screw with the bushing to retain the screw within the driver.
• This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
• The foregoing summary, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the embodiments, there are shown in the drawings example constructions of the embodiments; however, the embodiments are not limited to the specific methods and instrumentalities disclosed. In the drawings:
• FIG. 1A illustrates a driver device having an articulating driver head;
• FIG. 1B illustrates a sectional view of the driver device along section line A-A ofFIG. 1A;
• FIG. 1C illustrates a ball-in-socket joint of the driver devices ofFIG. 1A in greater detail;
• FIG. 2 illustrates a retention cap ofFIGS. 1A-1C;
• FIGS. 3A-3B illustrate a spherical head ofFIGS. 1A-1C in greater detail;
• FIG. 3C illustrates a sectional view of the spherical head along section line A-A ofFIG. 3B;
• FIG. 3D illustrates a sectional view of the spherical head along section line D-D ofFIG. 3A;
• FIG. 4A illustrates an articulation housing assembly ofFIGS. 1A-1C in greater detail;
• FIG. 4B illustrates a sectional view of the articulation housing assembly along section line B-B ofFIG. 4A;
• FIG. 4C illustrates a sectional view of the articulation housing assembly along section line A-A ofFIG. 4A;
• FIGS. 5-8 illustrate an engagement of a screw with a driver device such as that shown inFIG. 1;
• FIGS. 9-12 illustrate an interaction of a stop region of a bushing of the driver device and an aiming device to provide disengagement of the screw from the driver device according to an embodiment;
• FIGS. 13-20 illustrate an interaction of a stop region of a bushing of the driver device and an aiming device to provide disengagement of the screw from the driver device in accordance with another embodiment;
• FIGS. 21-25 illustrate another embodiment of the driver device of the present disclosure;
• FIG. 26 illustrates another embodiment of the driver device of the present disclosure;
• FIGS. 27A-27C illustrate another embodiment of the articulating driver of the present disclosure;
• FIGS. 28A-28C illustrate a first spherical head of the embodiment ofFIGS. 27A-27C;
• FIGS. 29A-29C illustrate a second spherical head of the embodiment ofFIGS. 27A-27C;
• FIGS. 30A-30B illustrate the articulation housing assembly of the embodiment ofFIGS. 27A-27C in greater detail; and
• FIG. 31 illustrates a perspective view of the embodiment ofFIGS. 27A-27C.
DETAILED DESCRIPTION
• With references to the FIGS., there is illustrated an articulatingdriver100 and a ball-in-socket joint102. As will be described herein, the ball-in-socket joint102 allows adriver tip126 or other output shaft to articulate while transmitting input torque from aninput shaft104 to thedriver tip126. The input torque turns e.g., a screw or other component being driven by the articulatingdriver100. The articulatingdriver100 may be a jointed awl, screw driver or drill.
• As shown inFIGS. 1A-1C, the articulatingdriver100 consists of theinput shaft104 that, at afirst end106, connects to a handle (not shown) and at asecond end108 connects to anarticulation housing assembly110 that forms an outer portion of the ball-in-socket joint102. Theinput shaft104 may be any type of shaft capable of transmitting input torque from the handle or a power tool to which theinput shaft104 is attached. At thesecond end108 of theinput shaft104, acavity114 is defined that accepts aspring116 or the cavity walls are composed of a spring. One end of thespring116 is received within thecavity114, and the other end of thespring116 is received within arecess118 of aretention cap120, which is shown in greater detail inFIG. 2. As will be described later, thespring116 provides positional retention of thedriver tip126. Theretention cap120 transmits force from thespring116 to aspherical head124 of thedriver tip126 that is secured between theretention cap120 and a taperedinner surface130 of thearticulation housing assembly110. As shown inFIG. 2, adomed surface122 may be defined at an end of theretention cap120 opposite therecess118 to receive thespherical head124.
• As shown inFIG. 1C, thearticulation housing assembly110 receives thesecond end108 of theinput shaft104, thespring116, theretention cap120, and thespherical head124 of thedriver tip126. As shown inFIG. 4, thearticulation housing assembly110 definesholes136 within which pins134a,134band134care pressed. Thepins134a,134band134care received withingrooves128a,128band128cof the spherical head124 (see,FIGS. 3A-3D). Through the cooperation of thepins134a,134band134cand thegrooves128a,128band128c, thespherical head124 transmits torque to an attachment that is received within a bushing132 (see,FIG. 1A). Thebushing132 provides positional retention of the attachment and may be made from Polyether ether ketone (PEEK) or an appropriate plastic or metal.
• In accordance with aspects of the present disclosure, thedomed surface122 of theretention cap120 and the taperedinner surface130 of thearticulation housing assembly110 may each have a radius that is similar to, and designed to interface with thespherical head124 head of thedriver tip126. These radii allow thedriver tip126 to articulate within thearticulation housing assembly110, while retaining thespherical head124 within thearticulation housing assembly110. Thus, the interaction of thespring116 pressing on theretention cap120, which mates to thespherical head124, and the taperedinner surface130 of thearticulation housing assembly110 serve to positionally retain thedriver tip126 within thearticulation housing assembly110.
• FIGS. 3A-3D illustrate thespherical head124 and thedriver tip126 in greater detail. As shown inFIG. 3A, thegrooves128a,128band128cform a generally ovular shape on the surface of thespherical head124, and are wider near the diameter and taper moving toward the circumference. Thegrooves128a,128band128care formed having generally having a W-shape cross-section (see,FIG. 3D) withinspherical head124. In some implementations, thegrooves128a,128band128cmay be milled into spherical head portion at offsets of 120°. As shown inFIG. 3C, the grooves may extend over an approximately 120° arc across the surface of thespherical head124. Thus, it can be appreciated that the shape of thegrooves128a,128band128cmaybe any shape such that the grooves cooperate with thepins134a,134band134cprovide approximately 45-50° of angulation of thedriver tip126 with respect to theinput shaft104 over a 360° rotation.
• During assembly, theinput shaft104 is pressed in thearticulation housing assembly110 and cross-pinned to thearticulation housing assembly110 using apin112. Thepin112 may be pressed-in and retained by an interference fit with theshaft104; thepin112 may be welded in place, or may be threaded into theshaft104 or retained within a further sleeve used to preventpins112,134a-134cfrom backing out. Other attachment mechanisms may be used in place of thepin112.
• The various components above may be made from stainless steel, titanium, titanium alloy, ceramic, etc. Theretention cap120 may be fabricated from PEEK, stainless steel, polyethylene, or any metallic or polymetric material. Theretention cap120 may also include a TiN coating to limit wear and galling on thespherical head124.
• In some implementations, the various components of thedriver100 may have the following dimensions. The radius of curvature of thedomed surface122 may be approximately 3.6 mm and may have a depth of 1.8 mm. Thespherical head124 portion may have a diameter approximately 6.5 mm. Therecess118 may have a depth of 1.5 mm to receive a portion of thespring116. Theretention cap120 may have a total height of 3.0 mm. The articulation housing assembly may have a length of 15 mm and the tapered inner surface may begin 1.6 mm from the edge of the housing assembly. The inner diameter of the articulation housing assembly may be 7.1 mm. The cavity defined in the second end of the input shaft may have a depth of 3.5 mm.
• During operation, as the user rotates theinput shaft104, torque is transmitted to thearticulation housing assembly110 via the press-fit and thepin112. This torque is then transmitted from thearticulation housing assembly110 to the driver tip via action of thepins134a,134band134care received within thegrooves128a,128band128cof thespherical head124 of thedriver tip126. Thedriver tip126 then transmits the torque to the attachment to turn, e.g., screws for insertion into bone.
• Thus, the ball-in-socket joint102 of the present disclosure can be positioned stabily in a multi-angle screwing/unscrewing operation. In particular, because the ball-in-socket joint102 provides for approximately 45-50° of angulation, thedriver100 maintains thedriver tip126 within a useful range of operation.
• Referring now toFIGS. 5-8, the engagement of a screw with the articulatingdriver100 will be described. As shown in detail in exploded view ofFIG. 5, abushing232 includesinner threads506 disposed at a distal end thereof andinner threads508 disposed at the proximal end thereof. The diameter of theinner threads506 andinner threads508 have a dimension that is complementary with an outer threadedportion514 of thescrew502 and a threadedregion510 of thedriver tip126, respectively. The pitches of theinner threads506 and outer threadedportion514, andinner threads508 and a threadedregion510 may be respectively optimized to match. The outer threadedportion514 may be a conical thread or a straight thread. In some implementations, the diameter of theinner threads506 may be larger than theinner threads508 to allow theinner threads506 to pass over the threadedregion510, as will be described below. In some implementations, the diameter of theinner threads506 and theouter threads508 may be the same.
• The bushing further includes astop region516, which cooperates with an aiming device or guide to halt forward progress of thebushing232 within the aiming device when thescrew502 is driven by the articulatingdriver100. Further details of the interaction of thestop region516 and the aiming device will be described below with reference toFIGS. 9-12. Also as shown, thedriver tip126 includes at a distal end thereof ascrew interface512 that is adapted to engage a complementary recess defined within the head thescrew502. Thescrew interface512 and complementary recess may be star-shaped, hexagonal, square, a polygonal shape, etc.
• The operational engagement of thebushing232, thedriver tip126 and thescrew502 will now be described.FIG. 5 illustrates the components in a separated state, where initially, thebushing232 is placed over thescrew interface512 to engage theinner threads508 with the threadedregion510. Thebushing232 is rotated in, e.g., a clockwise direction such that theinner threads508 mesh with the threadedregion510 to advance the bushing in the proximal direction. As shown inFIG. 6, thebushing232 may be moved in the proximal direction such that theinner threads506 pass over the threadedregion510, as the diameter of theinner threads506 may be larger than the threadedregion510. In implementations where the diameter of theinner threads506 is equal toinner threads508, the inner threads may engage the threadedregion510. As such, an intermediate state of engagement is achieved (shown inFIG. 6) where thescrew interface512 and a portion of the threadedregion510 protrude through the distal end of thebushing232. Thus, thescrew interface512 is positioned such that it can be received within a complementary recess in the head of thescrew502.
• Next, as shown inFIG. 7, thescrew502 is brought into proximity with thescrew interface512 such that the interface may engage the head of thescrew502. An operator may then rotate thebushing232 in e.g., the counterclockwise direction to cause theinner threads508 to mesh with the threadedregion510, thus moving thebushing232 in the distal direction.
• As shown in fully engaged view ofFIG. 8, thebushing232 is moved distally until theinner threads506 engage the threadedportion514 of thescrew502. The engagement of theinner threads506 and the threadedportion514 serves to retain thescrew502 within thebushing232. Thus,FIG. 8 illustrates thescrew502 when loaded into the articulatingdriver100 and ready to be driven into an associated plate or portion of bone.
• With reference toFIGS. 9-12, the operation of the articulatingdriver100 to drive thescrew502 into an associated plate or portion of bone will now be described. As shown inFIGS. 9-12, an aiming device or guide600 may be used to guide thescrew502. The aimingdevice600 includes a plurality of aimingholes604, each having apin602 that protrudes through an inner wall thereof at a distal end. An operator may drive thescrew502 into, e.g., bone, by inserting thescrew502 into an appropriate one of the aiming holes604. Thescrew502 will pass through the aiminghole604 and out of the aimingdevice600. However, the aimingdevice600 is sized such that thebushing232 remains rotably positioned within a proximal portion of the aiming hole604 (see, e.g.,FIG. 10). As the operator drives thescrew502 using thedriver100, thescrew502 andbushing232 will rotate and move distally within the aiminghole604 as thescrew502 engages the plate or bone.
• As shown inFIG. 11, the distal movement will cause thestop region516 of thebushing232 to engage thepin602. As illustrated inFIGS. 5 and 11, thestop region516 may be formed having a jagged or zig-zag edge, such that thepin602 is caught within a vertex516aformed by the edge. Engagement of thestop region516 with thepin602 will cause thebushing232 to cease rotational and longitudinal movement (i.e., it will be stopped within the aiming hole604). It is noted that other designs may be used to stop the advancement of thebushing232 within the aiming hole604 (e.g., frictional engagement).
• After thebushing232 is stopped, the application of torque to thedriver tip126 will continue to rotate thescrew502 within thebushing232. Thus, thescrew502 will continue to be driven in the distal direction along the longitudinal axis of thedriver tip126. As shown inFIG. 12, continuing to drive thescrew502 will rotate the threadedregion514 within theinner threads506, causing the threadedregion514 to progress out of the distal end of thebushing232. As such, thescrew502 advances from thebushing232 and will be released from thedriver100. Operation of the articulatingdriver100 may continue in order to drive thescrew502 into its final position through the continued engagement of thescrew interface512 with the head of thescrew502. Once thescrew502 reaches its final position, the articulatingdriver100 may be withdrawn from the aiming device or guide600.
• Referring now toFIGS. 13-20, the engagement of a screw with the articulatingdriver100 will be described in accordance with another implementation. Many of the details of the articulatingdriver100 of this implementation are the same as the that described with reference toFIGS. 1-12; however, as shown in detail inFIGS. 13 and 14, abushing732 includes inner threads706 (FIG. 14) disposed at a distal end thereof andinner threads708 disposed at the proximal end thereof. The diameter of theinner threads706 andinner threads708 have a dimension that is complementary with an outer threadedportion514 of thescrew502 and a threadedregion510 of thedriver tip126, respectively. The pitches of theinner threads706 and outer threadedportion514, andinner threads708 and a threadedregion510 may be respectively optimized to match. The outer threadedportion514 may be a conical thread or a straight thread. In some implementations, the diameter of theinner threads706 may be larger than theinner threads708 to allow theinner threads706 to pass over the threadedregion510, as will be described below. In some implementations, the diameter of theinner threads706 and theouter threads708 may be the same.
• Thebushing732 further includeslobes734, which cooperate with an aiming device or guide to halt forward progress of thebushing732 within the aiming device when thescrew502 is driven by the articulatingdriver100. The cooperation of thelobes734 with the aiming device is described below in more detail with reference toFIGS. 17-20. Thelobes734 may be formed such that they extend outwardly from the circumference of thebushing732. Three or fourlobes734 may be provided at the proximal end of thebushing732; however any number of lobes may be provided.
• The operational engagement of thebushing732, thedriver tip126 and thescrew502 will now be described.FIG. 14 illustrates the components in a separated state, where initially, thebushing732 is placed over thescrew interface512 to engage theinner threads508 with the threadedregion510. Thebushing732 is rotated in, e.g., a clockwise direction such that theinner threads508 mesh with the threadedregion510 to advance the bushing in the proximal direction. As shown inFIG. 15, thebushing732 may be moved in the proximal direction such that theinner threads506 pass over the threadedregion510, as the diameter of theinner threads506 may be larger than the threadedregion510. In implementations where the diameter of theinner threads506 is equal toinner threads508, the inner threads may engage the threadedregion510. As such, an intermediate state of engagement is achieved (shown inFIG. 15) where thescrew interface512 and a portion of the threadedregion510 protrude through the distal end of thebushing232. Thus, thescrew interface512 is positioned such that it can be received within a complementary recess in the head of thescrew502.
• Next, as shown in fully engaged view ofFIG. 16, thebushing732 is moved distally until theinner threads506 engage the threadedportion514 of thescrew502. The engagement of theinner threads506 and the threadedportion514 serves to retain thescrew502 within thebushing732. Thus,FIG. 16 illustrates thescrew502 when loaded into the articulatingdriver100 and ready to be driven into an associated plate or portion of bone.
• With reference toFIGS. 17-20, the operation of the articulatingdriver100 to drive thescrew502 into an associated plate or portion of bone will now be described. As shown inFIGS. 17-20, an aiming device or guide800 may be used to guide thescrew502. The aimingdevice800 includes a plurality of aimingholes804, each having circumferential lobes802 at a proximal end. The circumferential lobes802 may extend inwardly from a center of each aiminghole804 and receive thelobes734 of thebushing732. An operator may drive thescrew502 into, e.g., bone, by inserting thescrew502 into an appropriate one of the aiming holes804. Thescrew502 will pass through the aiminghole804 and out of the aimingdevice800. However, the aimingdevice800 is sized such that thebushing732 remains rotably positioned within a proximal portion of the aiming hole804 (see, e.g.,FIG. 18). As the operator drives thescrew502 using thedriver100, thescrew502 andbushing732 will rotate and move distally within the aiminghole804 as thescrew502 engages the plate or bone.
• As shown inFIG. 19, the distal movement will cause thelobes734 of thebushing732 to be received within the lobes802. As illustrated inFIGS. 13 and 17, thelobes734 and the lobes802 may be formed having complementary shapes such that thelobes734 are received with the complementary shaped lobes802. Engagement of thelobes734 and lobes802 will cause thebushing732 to cease rotational and longitudinal movement (i.e., it will be stopped within the aiming hole804).
• After thebushing732 is stopped, the application of torque to thedriver tip126 will continue to rotate thescrew502 within thebushing732. Thus, thescrew502 will continue to be driving in the distal direction along the longitudinal axis of thedriver100. As shown inFIG. 20, continuing to drive thescrew502 will rotate the threadedregion514 within theinner threads506, causing the threadedregion514 to progress out of the distal end of thebushing732. As such, thescrew502 advances from thebushing732 and will be released from thedriver100. Operation of the articulatingdriver100 may continue in order to drive thescrew502 into its final position through the continued engagement of thescrew interface512 with the head of thescrew502. Once thescrew502 reaches its final position, the articulatingdriver100 may be withdrawn from the aiming device or guide800.
• FIGS. 21-25 illustrate another embodiment of an articulating driver1300 of the present disclosure. As shown, the articulating driver1300 may include three components, a central screwdriver (FIG. 21), a central sleeve (FIG. 22) and an outer, slip sleeve (FIG. 23). Thecentral screwdriver1301 may be a straight or jointed driver. As illustrated inFIGS. 24A and 24B, the central screwdriver may be a jointed driver which is composed of aproximal shaft1301 which has aninterface1301athat is adapted to provide a connection to, e.g., a handle for applying torque. The central screwdriver may include a jointed feature (e.g., a universal joint1308) and a distal portion containing thescrew interface1306a(e.g., a self retaining star-drive). Alternatively, thejoint mechanism1308 may accomplished by beam coupling, spring coupling, jaw coupling, etc. Alternatively, thescrew interface1306amay have a hexagonal, square, polygonal shape, etc. The central screwdriver may include adistal tip1306 that at a proximal end thereof, includes acircumferential groove1313 to allow for retention of the central sleeve.
• Referring now toFIG. 22, the central sleeve may include amechanism1302 to retain the central sleeve on the central screwdriver ofFIG. 21. For example, themechanism1302 may be a spring-loaded quick coupling with detents for retention on the circumferential groove of the central screwdriver. Between the proximal end and the distal tip, there is ahelical structure1304 that may be provided to allow for bending of the jointedsegment1308 when the central sleeve is assembled. The nature of the helical structure1034 allows it to act as a spring and hence bend with thejoint segment1038. Thehelical structure1304 may be manufactured from a single solid tube with the central sleeve or may be bonded to the proximal and distal portion as a separate element. The later alternative would enable the use of any material that would be appropriate for thehelical structure1304. Such materials could be, but are not limited to, Nitinol, spring steel, certain grades of stainless steel or any other material which offers appropriate elasticity/memory. An additional benefit of thehelical structure1304 and its associated memory is that it prevents the loosening of jointed instruments, which is often encountered when there is repeated use of jointed instruments with universal joints.
• At the distal tip of the central sleeve, adistal portion1305 is providing having an outer diameter and length so as to have an appropriate interface with an aiming device or guide (e.g.,600) which may be used in association with the driver. An internal thread at the distal tip1309 (FIG. 25) may engage the screw which would have to have either a straight or conical thread on the external surface of its head. The pitch of this internal thread would be optimized to match that of the thread on the screw.
• To assemble the screw to the driver, thescrew interface1306amay protrude slightly out of the tip of the central sleeve. The screw would engage thescrew interface1306aof the driver, which may be a self-retaining interface. Then, using the retention mechanism1032 of the central sleeve to act also as a turning knob, the central sleeve is turned such that theinternal thread1309 engages the external thread of the screw head. In turning this central sleeve, one or both of the following may occur, the screw is pulled further onto thescrew driver interface1306aor thehelical structure1304 elongates as theinternal thread advances1309 over the screw head. The screw is then rigidly fixed to the screwdriver via the threaded connection to the central sleeve and the connection of the central sleeve to the central driver. The screw is also connected to the central driver via thescrew interface1306awhich allows for torque transmission and screw placement.
• As the operator advances the screw, there may be a tendency to hold the length of the driver for guidance. If this holding occurs on the central sleeve, it may result in early disengagement of the screw from the central sleeve as the central sleeve would remain stationary relative to a rotating screw driver and screw. In order to prevent this from occurring, anouter slip sleeve1311 may be positioned on the outside of the central sleeve. Thisslip sleeve1311 may freely rotate about the central sleeve due to a nonrigid connection1310. Thisconnection1310 allows for rotation, but restricts translation. In addition, at the distal end of the slip sleeve, there is located a flexibleplastic sleeve1312 that covers the helical portion from entangling surrounding tissue.
• As the screw nears its final position, the thread on its head engages an associated plate or portion of bone. However, in the insertion position, this head is covered by the central sleeve. Here, the user knows when to disengage the central sleeve. An alternative method involves the placement oftoothed features1307 on the distal portion of the central sleeve, which when approaching the final position, will engage into a counter-feature or the bone and will result in fixing the central sleeve from rotating with the central driver. Further rotation of the central driver will result in automatic disengagement of the screw from the central sleeve. The helical structure will allow the central sleeve can collapse with the advancement while the screwdriver-screw interface remains for optimum torque transmission. Once, the screw has been tightened into place, it will be no longer be connected to the driver itself and the driver is free to be removed.
• In some implementations, in order to prevent deformation of the helical structure through over tightening of the central sleeve onto the screw, the helical structure may spiral in the opposite direction of the thread (i.e., counter-clockwise helical structure is provided for a clockwise thread). Therefore, over tightening will result in the helical structure collapsing onto the inner screwdriver and hence preventing it from deforming outward.
• FIG. 26 illustrates another embodiment that uses an external thread on the central sleeve which would mate to a corresponding internal thread on the screw. Such a configuration may be used with variable angle screws or pedicle screws, and screws with locking threads.
• In yet another embodiment, the design ofFIGS. 21-25 may omit thetoothed feature1307. Turning of the screw with the head covered will result in engagement of the central sleeve onto the aiming device. Subsequent turning of the screw after this condition is achieved will result in lagging of the plate to the bone into which the screw is purchased or vice-versa.
• FIGS. 27-31 illustrate another embodiment of a joint2702 of the articulating driver of the present disclosure. As shown inFIGS. 27A-27C, the articulating driver2700 consists of aninput shaft2704 that, at afirst end2706, connects to a handle (not shown) and has a firstspherical head2708. The firstspherical head2708 is secured within anarticulation housing assembly2710 by afirst pin2712 that passes through acavity2709. Theinput shaft2704 may be any type of shaft capable of transmitting input torque from the handle or a power tool to which theinput shaft2704 is attached. A secondspherical head2724 is formed at a proximal end of adriver tip2726 and is secured to thearticulation housing assembly2710 by asecond pin2734 that passes through a cavity2729. When secured within thearticulation housing assembly2710, aball2718 formed at the distal end of the firstspherical head2708 is received within asocket2722 that is defined within a proximal end of the secondspherical head2724, the interaction of the various components is described further with reference toFIG. 31.
• As shown inFIG. 27C, enclosed within thearticulation housing assembly2710 is the firstspherical head2708 of theinput shaft2704, afirst washer2712, aspring2716, asecond washer2720, andspherical head2724 of thedriver tip2726. Thespring2716 is disposed between a first washer2714 and asecond washer2720. The first washer2714 has a tapered edge that abuts the firstspherical head2708 and thesecond washer2720 has a tapered edge that abuts the secondspherical head2734. Thespring2716 exerts an expansion force on both the first washer2714 and thesecond washer2720 to frictionally positionally retain the firstspherical head2708 and the secondspherical head2734 within the housing assembly2710 a user-set angulation. The proximal and distal openings of thearticulation housing assembly2710 each have a chamferededge2711 and2730, respectively, that are adapted to abut afirst base2705 and a second base2727 to act as a stop to limit the total angulation of the joint2702, as described below.
• FIGS. 28A-28C illustrate the firstspherical head2708 in greater detail. As shown inFIG. 28A, thecavity2709 forms a generallyovular opening2717 on a surface of the fist spherical head2708 (a bottom opening is not shown in the FIGS.). In some implementations, thecavity2709 may be milled into firstspherical head2708 having a generally “bow-tie” shape. As shown in the cross-sectional view ofFIG. 28C, thecavity2709 may be formed such theopening2717 extends having an approximately 22° arc in each direction with respect to a center axis of the cavity2709 (providing a total arc of approximately 44° across the surface of the first spherical head2708). The “bow-tie” shaped of thecavity2709 enables the firstspherical head2708 to be angulated with respect to thefirst pin2712 passing therethrough, which can be appreciated is positioned along the center axis of thecavity2709 shown inFIG. 28C when the firstspherical head2708 is assembled into the joint2702.
• FIGS. 29A-29C illustrate the secondspherical head2724 in greater detail. As shown inFIG. 29A, thecavity2725 forms a generallyovular opening2728 on the surface of the second spherical head2724 (a bottom opening is not shown of the FIGS.). In some implementations, thecavity2725 may be milled into secondspherical head2724 having a “bow-tie” shape similar to thecavity2709. As shown in the cross-sectional view ofFIG. 29C, thecavity2725 may be formed such theopening2728 extends in a 22° arc in each direction with respect to a center axis of thecavity2725. Thus, similar to thecavity2709, the “bow-tie” shapedcavity2725 enables the secondspherical head2724 to be angulated with respect to thesecond pin2734, which can be appreciated is positioned along the center axis of thecavity2725 shown inFIG. 29C when the second spherical head is assembled into the joint2702.
• As shown inFIG. 30A-30B, thearticulation housing assembly2710 definesholes2736 into which thefirst pin2712 and thesecond pin2734 may be pressed.Openings2740 are provided to enable easy cleaning of the interior of the articulatinghousing assembly2710.FIG. 30B illustrates the chamferededges2711 and2730 of the proximal and distal openings of thearticulation housing assembly2710. Each edge may be formed having approximately a 20° angle with respect to the longitudinal axis of thearticulation housing assembly2710. The chamfered edges2711 and2730 may abut thefirst base2705 and the second base2727 to limit the total angulation at approximately 40°.
• FIG. 31 illustrates a perspective view of the assembled joint1702. To assemble the joint1702, theinput shaft2704 is inserted into thearticulation housing assembly2710 and pinned to thearticulation housing assembly2710 by thefirst pin2712. Thefirst washer2712, thespring2716 and thesecond washer2720 are then placed within thearticulation housing assembly2710. Thedriver tip2726 is inserted into thearticulation housing assembly2710 and pinned by thesecond pin2734. Thepins2712 and2734 may be pressed-in and retained by an interference fit with the articulatinghousing2710; thepins2712 and2734 may be welded in place, or may be threaded into articulatinghousing2710. Other attachment mechanisms may be used in place of thepins2712 and2734.
• The various components above may be made from stainless steel, titanium, titanium alloy, ceramic, etc. Thefirst washer2712 and thesecond washer2720 may be made from PEEK. Thespring2716 may be any spring having a spring constant to exert a sufficient force on thefirst washer2712 and thesecond washer2720 to provide the aforementioned positional retention of the firstspherical head2708 and the secondspherical head2724 within the articulatinghousing2710.
• During use, a user can initially position theinput shaft2704 and thedriver tip2726 by angulating theinput shaft2704 and thedriver tip2726 to a desired total angulation. The approximately 22° of angulation of the firstspherical head2708 and the approximately 22° of angulation of the secondspherical head2724 may provide for a total angulation of approximately 44° of thedriver tip2726 with respect to theinput shaft2704. However, as noted above, the total angulation may be limited to approximately 40° by the interaction of the chamferededges2711 and2730 and thefirst base2705 and the second base2727. The angulation may be maintained throughout a 360° rotation of theinput shaft2704 anddriver tip2726 by the positional retention provided by the interaction of thespring2716, the first washer2714 and thesecond washer2720 and the constant velocity provided by theball2718 and thesocket2722.
• As the user rotates theinput shaft2704, torque is transmitted to thearticulation housing assembly2710 via the interaction of thefirst pin2712 within thecavity2709 of the firstspherical head2708. This torque is then transmitted from thearticulation housing assembly2710 to the driver tip via action of thesecond pin2734 within thecavity2725 of the secondspherical head2724 of thedriver tip2726. Thedriver tip2726 then transmits the torque to the attachment to turn, e.g., screws for insertion into bone.
• Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims (30)

What is claimed:

1. A driver having a ball-in-socket joint, comprising:

a driver tip having a spherical head;

a retention cap having a domed surface to mate with the spherical head;

an input shaft;

a spring disposed in an end of the input shaft and in a recess of the retention cap opposite that of the domed surface; and

a housing that receives the input shaft, the spring, the retention cap and the spherical head,

wherein the housing has a tapered end to positionally retain the spherical head therein.

2. The driver ofclaim 1, wherein the spherical head has a plurality of grooves defined in a surface thereof, wherein the housing defines a plurality of holes, and wherein each of the holes receives a pin that passes through the housing and is received within a respective groove of the spherical head.

3. The driver ofclaim 2, wherein torque applied at the input shaft is transmitted to the housing and to the driver tip by action of the pins within the grooves of the spherical head.

4. The driver ofclaim 2, wherein the plurality grooves have a shape to provide for up to 50° of angulation of the driver tip with respect to the input shaft over a 360° rotation of the input shaft.

5. The driver ofclaim 4, wherein the grooves have a generally ovular shape and a W-shape cross-section within spherical head.

6. The driver ofclaim 2, wherein the grooves are positioned within spherical head at offsets of approximately 120°.

7. The driver ofclaim 2, wherein the grooves extend over an approximately 120° arc across a face of the spherical head.

8. The driver ofclaim 1, wherein the spring exerts a force on the retention cap to positionally retain the spherical head within the housing.

9. A ball-in-socket joint, comprising:

an input shaft;

an output shaft having a spherical head, the spherical head having a plurality of grooves defined therein;

a retention cap having a domed surface to mate with the spherical head;

a spring disposed in an end of the input shaft and in a recess of the retention cap opposite that of the domed surface; and

a housing the defines a plurality of holes, the housing receiving the input shaft, the spring, the retention cap and the spherical head,

wherein the housing positionally retains the spherical head therein, wherein each of the holes receives a pin that passes through the housing and is received within a respective groove of the spherical head.

10. The ball-in-socket joint ofclaim 9, wherein torque applied at the input shaft is transmitted to the housing and to a driver tip associated with the output shaft by action of the pins within the grooves of the spherical head.

11. The ball-in-socket joint ofclaim 9, the housing further comprising a tapered end, wherein the domed surface and tapered end each have a radius of curvature that is approximately equal to a radius of the spherical head, and wherein the tapered end and the domed surface positionally retain the spherical head within the housing.

12. A driver, comprising:

an input shaft adapted to transmit torque;

a driver tip coupled to the input shaft, the driver tip including an interface defined at an end thereof adapted to engage a screw; and

a bushing that engages the driver tip at one end and receives the screw at the other end,

wherein the screw is received within the bushing and engages the interface, and

wherein the input shaft is adapted to apply torque to the screw through the interface and to apply torque to the bushing by the engagement of the bushing with the driver tip.

13. The driver ofclaim 12, wherein the bushing includes inner threads disposed at a distal end thereof and inner threads disposed at a proximal end thereof.

14. The driver ofclaim 13, wherein the driver tip further comprises a threaded region that engages the inner threads disposed at the proximal end of the bushing.

15. The driver ofclaim 14, wherein the inner threads at the distal end of the bushing are adapted to pass over the threaded region of the driver tip.

16. The driver ofclaim 13, wherein the screw further comprise an outer threaded portion on an external surface of a head of the screw, the outer threaded portion adapted to engage the inner threads disposed at the distal end of the bushing.

17. The driver ofclaim 12, the bushing further comprising a stop region, wherein the stop region cooperates with an aiming device to hold the bushing within the aiming device as torque is transmitted to the screw and the bushing.

18. The driver ofclaim 17, wherein when torque continues to be applied to the screw after the bushing is held within the aiming device, the screw releases from the bushing.

19. The driver ofclaim 17, wherein the stop region is formed having a zig-zag shaped edge, and wherein the forward progress of the bushing is halted by an interaction of a pin of the aiming device with a vertex formed by the zig-zag shaped edge.

20. The driver ofclaim 17, wherein the stop region comprises a plurality of lobes that extend outward from a center of the bushing, and wherein the forward progress of the bushing is halted by an interaction of a plurality of complementary lobes that extend inwardly from a center of an aiming hole of the aiming device.

21. A driver having a double-wobble joint, comprising:

an input shaft having a first spherical head that includes a distal ball;

a driver tip having a second spherical head that includes a proximal socket that is adapted to receive the distal ball;

a housing that receives the input shaft and the driver tip; and

a spring disposed between a first washer and a second washer in the housing, the first washer being disposed between a proximal end of the spring and the first spherical head, and the second washer being disposed between a distal end of the spring and the second spherical head, the spring providing an urging force on the first washer and the second washer within to positionally retain the first spherical head and the second spherical head within the housing.

22. The driver ofclaim 21, wherein the first spherical head defines a first cavity and the second spherical head defines a second cavity, wherein a first pin is disposed within the first cavity to secure the first spherical head to the housing, and wherein a second pin is disposed within the second cavity to secure the second spherical head to the housing.

23. The driver ofclaim 22, wherein the cavity is formed having a generally bow-tie shape.

24. The driver ofclaim 22, wherein the first cavity extends through first spherical head to form an upper opening and a lower opening on a surface of the first spherical head, and wherein the second cavity extends through second spherical head to form an upper opening and a lower opening on a surface of the second spherical head.

25. The driver ofclaim 24, wherein the upper opening and the lower of the first spherical head and the upper opening and the lower of the second spherical head each extend across an arc of approximately a 44° across a surface of the first spherical head and the second spherical head, respectively.

26. The driver ofclaim 22, wherein torque applied at the input shaft is transmitted to the housing and to the driver tip by action of the first pin within the first cavity and the second pin within the second cavity.

27. The driver ofclaim 22, wherein the first cavity and the second cavity provide approximately 44° of angulation of the driver tip with respect to the input shaft over a 360° rotation of the input shaft.

28. The driver ofclaim 27, wherein the housing defines chamfered edges at a proximal opening and a distal opening, wherein the driver tip and the input shaft each define a base that is adapted to contact the chamfered edges to limit the angulation of the driver.

29. The driver ofclaim 28, wherein the limit of the angulation is approximately 40°.

30. The driver ofclaim 21, wherein an interaction of the distal ball within the socket provides for a constant velocity in the double-wobble joint.

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