USRE41424E1 - Torque responsive actuation device - Google Patents

Abstract

The invention is in a torque responsive actuation device, preferably for a belt drive system as is commonly utilized with snowmobile and like type vehicles. A bearing carrier of the invention is connected to a lower half of a split pulley, with the upper pulley half mounting a helix or cam cone that extends towards the carrier undersurface and includes a plurality of cam tracks formed therein that are each to receive a cam follower for travel therealong. Movement of the bearing carrier towards the top face of the pulley upper half is thereby translated to lower the pulley half to spread the pulley upper and lower halves apart, opening a V slot therebetween wherein a drive belt is maintained. A cylindrical shaft is journaled through the bearing carrier and fitted through the pulley that includes a coil spring disposed therearound for providing spring biasing to urge the bearing carrier away from the pulley upper half, biasing the pulley halves together. To provide minimum friction operation and wear the invention employs cam follower bearings as the cam followers and radiuses either the outer surface of rollers of each cam follower bearing or of the cam tracks to be convex and to have an apex that contacts and rolls along a center line of the opposing surface, the roller of each bearing to travel through a variety of cam angles during operation of the torque responsive actuation device.

Description

RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No.08/323,611, filed Oct.17,1994, now U.S. Pat. No.5,516,333.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to clutch type systems and in particular to a torque responsive actuation devices that include roller bearings arranged to travel along helix tracks to open and closing opposing pulley halves for a belt driven power train as is commonly used for snowmobiles, and the like.

2. Prior Art

The present invention is in a torque responsive actuation device that incorporated bearings arranged travel along helix tracks, functioning as a clutch for a belt driven power train. The invention improves upon prior systems by providing for radiusing either the bearing or track whereon it travels, the bearing to travel along a center line of the helix track, with bearing travel to spread apart pulley halves wherearound a continuous drive belt is positioned. The pulley opening is matched by closure of a drive clutch. So arranged, based upon engine speed, the one clutch will open its pulley, thereby reducing the radius of pulley that the belt travels around, as the other clutch closes its pulley, thereby increasing the pulley radius. The belt is tightly maintained within the pulleys with changes in applied torque producing changes in the radiuses of the respective clutch pulleys.

Examples of earlier devices for varying pulley diameter responsive to torque are shown in U.S. Patents to: Steurer, U.S. Pat. No. 3,722,308; Togami, et al. No. 4,173,155; Huff, U.S. Pat. No. 4,378,221; Marier, U.S. Pat. No. 4,585,429; and Smith, et al, U.S. Pat. No. 5,403,240. The desirability of decreasing friction and diminishing binding between bearings and the helix tracks whereon they travel was recently recognized in a patent application of the present inventor, entitled “Torque Responsive Actuation Device for a Belt Drive System” U.S. patent application Ser. No. 08/323,611, filed Oct. 17, 1994, now U.S. Pat. No. 5,516,333 that the present invention improves upon.

In applicant's earlier patent application, only the helix cam tracks that individual roller bearing travel along were shown radiused, each presenting a convex surface therealong. These curved surfaces provide for centering the roller of each roller bearing as it rolls therealong, providing for a very smooth clutch upshift and backshift relative movement with less component wear than earlier clutch arrangements experience. The present invention further recognizes that any torque sensing type of clutch arrangement that utilizes a bearing a cam can include a radiusing of either of the opposing bearing or helix surfaces to obtain the benefits as set out in the above cited U.S. Patent Application.

SUMMARY OF THE INVENTION

It is a principal object of the present invention in a torque responsive actuation device to provide a torque sensing system that is operated to produce near frictionless pulley ratio shift changes.

Another object of the present invention is to provide a torque responsive actuation device that is easily operated and provides a high degree of torque sensitivity and efficiency so as to allow for quick and precise upshifting and backshifting.

Another object of the present invention is to provide a torque responsive actuation device with bearings that travel along individual tracks of track sections of a helix or cam cone, with either opposing bearing or track surface to have a convex surface with a greatest diameter of the convex surface preferably at the surface center so as to provide a point contact between the bearing surfaces that will remain centered during travel of the one surface over the other.

Still another object of the present invention is to provide a torque responsive actuation device where either of the opposing bearings or track surfaces have convex surfaces formed thereacross.

Still another object of the present invention is to provide a torque responsive actuation device for use in belt driven vehicles, such as snowmobiles, or the like, where either of the individual roller bearing contact surfaces are radiused thereacross that each engage and roll along the center of a track, through a variety of cam angles as could otherwise create side loads on the bearings, thereby providing a torque responsive actuation device that will exhibit easy, smooth, efficient and essentially frictionless shifting over a long service life.

In accordance with the above objects of the present invention is in a torque responsive actuation device as for example, for a belt drive system that includes a pulley formed from upper and lower halves that, when fitted together, form a deep V therebetween that receives a drive belt disposed therein.

For the invention, bearings, as set out below, are arranged to travel along each of a plurality of cam tracks, spreading apart pulley halves to function as a clutch. With each bearing roller centered on the cam track as it rolls therealong, avoiding track edge wear and a possibility of a bearing roller binding at the track edge from side loads, to provide bearing roller centering, either the roller surface or the track surface is radiused thereacross, or includes a center triangular pack therealong. The radius or height of the surface is selected such that the roller traveling along the track will follow a path along the track center throughout a variety of cam angles. Though, it should be understood, the invention can be in any clutch type device where opposing bearing surfaces are fitted together with rollers, or the like, to travel along tracks. In which arrangements, either the roller or track surfaces are provided with a radiused surface of apex to provide point contact therebetween that will remain centered during travel.

In a first embodiment, an upper pulley half includes a center hole and with spaced holes wherethrough piers from the lower pulley half extend. The piers are equally spaced radially from the lower pulley half center and project past the upper pulley half top surface. Also mounted to extend upwardly from the upper pulley half top face is a cylindrical helix or cam cone that includes at least three identically equal spaced helix or cam sections formed therein. The helix or cam sections are each equally spaced radially from the upper pulley half center. The identical helix or cam sections are preferably formed by appropriately machining a metal cylindrical section to leave a flat bottom surface that is arranged to be mounted to the upper pulley half top surface such that the helix or cam cone extends at approximately a right angle outwardly therefrom.

Each helix or cam section includes a cam track formed from a lower corner at the junction of a cylindrical ring bottom end and upper pulley half top face, and extending straight across the cylinder segment to an upper distant corner thereof. Each cam track is angled upwardly from the pulley half upper face, and is formed to be flat thereacross.

The preferred roller bearings for this embodiment are preferably three individual sealed needle bearing that are each journaled to extend at right angles from the side of posts that are each themselves secured at equal spaced radial intervals to extend outwardly from an actuation or clutch cover plate assembly undersurface. The posts are each adjacent to an arcuate slot that has been formed through the actuator or clutch cover plate wherethrough the helix of cam cone track sections project when the clutch cover plate undersurface is moved towards the pulley half upper face. The clutch cover plate is guided on a cylindrical shaft that is journaled, at a right angle, through a bushing that is maintained in a center hole of the clutch cover plate and a hole formed through the pulley center.

For a second embodiment roller bearings are maintained across cavities of a cylindrical bearing carrier, rolling along tracks of a helix or cam cone. As with the first embodiment, the helix or cam cone is mounted to, to extend upwardly from, the clutch cover plate under surface, with the cylindrical bearing carrier function like the clutch cover plate and is guided, like the clutch cover plate, on the cylindrical shaft.

For both embodiments, the cylindrical shaft is secured to the upper pulley half and is journaled through and extends beyond the lower pulley half, with clutch cover plate, cylindrical bearing carrier movement towards the upper pulley half top face to separate the upper and lower pulley halves to operate the torque responsive actuation device of the invention.

To urge the clutch cover plate cylindrical bearing carrier and upper pulley half apart, a coil spring is preferably disposed over the cylindrical shaft with the spring ends contacting the opposing clutch cover plate, cylindrical bearing carrier undersurface and upper pulley half top face, biasing them apart. This biasing is overcome by moving the clutch cover plate, cylindrical bearing carrier towards the upper pulley half, thereby separating the pulley halves, to open the pulley V, reducing the radius thereof.

THE DRAWINGS

The following drawings illustrate that which is presently regarded as the best mode for carrying out the invention:

FIG. 1 is a first embodiment of a torque responsive actuation device of the present invention, showing upper and lower pulley halves closed together with a drive belt maintained therebetween;

FIG. 2 shows the torque responsive actuation device ofFIG. 1 as a top plane perspective view to illustrate the operation thereof where an actuator cover plate assembly is moved toward an upper pulley half top face, thereby moving a lower pulley half away from which upper pulley half, opening a V formed between which pulley halves;

FIG. 3 is a bottom plan enlarged perspective view of the actuator cover plate assembly of the torque responsive actuation device ofFIGS. 1 and 2;

FIG. 4 is a side elevational perspective view of the helix or cam cone of the torque responsive actuation device ofFIGS. 1 and 2 removed from its mounting onto the top face of the upper pulley half;

FIG. 4A is a top plan sectional view taken along theline4A—4A ofFIG. 4 showing the helix or cam track as radiused;

FIG. 4B is a view like that ofFIG. 4A only showing the helix or cam track as having a center apex with equal flat sides sloping downwardly therefrom to intersect cam section sides;

FIG. 4C is a view like that ofFIG. 4B only showing the helix or cam track as having been flattened below the apex;

FIG. 5 is a top sectional view taken along theline5—5 ofFIG. 4 showing the flat surface of the helix or cam track and showing a radiused cam follower roller journaled on an axle, shown in broken lines, so as to extend outwardly from an upright post of the actuator cover plate;

FIG. 5A is a view like that ofFIG. 5 only showing the cam follower roller having a center apex with equal flat sides sloping downwardly therefrom to the roller side;

FIG. 5B is a view like that ofFIG. 5A only showing the cam follower roller as having been flattened below the apex;

FIG. 6 is a top plan view of the helix or cam cone ofFIG. 4;

FIG. 7 is an exploded side elevational perspective view of a second embodiment of a torque responsive actuation device of the present invention showing upper and lower pulley halves separated with a helix or cam track shown aligned for fitting to an upper pulley half, and with a cylindrical bearing carrier aligned with a coil spring and cylindrical shaft for mounting to a lower pulley half;

FIG. 8 is an enlarged bottom plan view of the cylindrical bearing or carrier ofFIG. 7;

FIG. 9 is an enlarged side elevational perspective view of the helix or cam cone ofFIG. 7; and

FIG. 9A is an enlarged sectional view taken along theline9A—9A of FIG.9.

DETAILED DESCRIPTION

FIGS. 1 and 2 show side elevation and top plan perspective views of a first embodiment of a torqueresponsive actuation device20 of the invention, hereinafter referred to asactuation device20. While theactuation device20 is a significant departure from earlier driven clutch assemblies, its functions are similar to my earlier U.S. Patent Application for “A Torque Responsive Actuation Device for a Belt Drive System” Ser. No. 08/323,611 now U.S. Pat. No. 5,516,333. Unique therefrom, however, is the configuration of the respective cam follower bearing rollers and the cam tracks wherealong the rollers travel, as set out and described herein. According, it should be understood, the description of the Torque Responsive Actuation Device of the above cited U.S. Patent Application, and its functioning should be taken as a description appropriate to theactuation device20 of the present invention, and accordingly the disclosure of this U.S. patent application Ser. No. 08/323,611 now U.S. Pat. No. 5,516,333, is incorporated herein by this reference. Similar to the above cited U.S. Patent Application, the first and second embodiments of the present invention include configuration of cam follower bearings that each include a roller type device arranged for traveling along a helix or cam track. The configuration of the roller surfaces or helix or cam track of the earlier patent application and present invention are to provide for minimizing wear and friction between components and to preclude roller binding due to side loads as occur when a roller travels to a track edge.

As with my earlier U.S. patent application Ser. No. 08/323,611 now U.S. Pat. No. 5,516,333, for theactuation device20, individual actuator cover plate helix or cam track wear and roller binding are dramatically improved by providing for a radiusing of each bearing, as shown best inFIGS. 3,4 and5, to form a convex surface thereacross. Which The convex surface to may have a greatest height at the bearing center, to guide bearing travel along the center of the flat cam track, as shown in FIG.5. The roller center is thereby maintained equidistant from the track edges. Heretofore,, earlier arrangements, involved bearing and cam track surfaces that were both flat with a path of travel of each clutch plate roller, or, as in earlier arrangements slides, was from one cam track edge to the other, creating side loads on the bearing or slides during operation as the bearing or slide traveled through the varied cam angles during travel over the cam track. Such side lobes produced unequal roller or slide and cam track wear as the roller changed position through varied cam angles during its travel from one cam track side to the other, often causing bearing binding and damage. Such earlier clutches, are both stiff and hard to operate and have required frequent repair to replace worn slides or roller bearings. Distant therefrom, the present invention provides an actuation devices that provide smooth and easy operation, exhibit a minimum of wear on cam follower bearing rollers, and provide for a quick shifting at essentially a zero over-rev condition. Further, as individual roller travel of the present invention remains centered longitudinally along a cam track, side loads on each cam follower roller as are present at the track edges that may cause roller binding and damage are negated.

Theactuation device20, as shown inFIGS. 1 and 2, includes anactuator cover plate21, that is shown inverted inFIG. 3 from its arrangement inFIGS. 1 and 2. As shown best inFIG. 2, the actuatorcover plate undersurface22 is essentially parallel to an upper ortop face24 of anupper pulley half23a of apulley23. Thepulley23 consists of upper and lower pulley halves23a and23b, respectively, that have, when closed together, a deep V that adrive belt25 will fit into. To provide pulley separation, reducing the pulley effective radius relative to thedrive belt25 thelower pulley half23, as shown inFIG. 2, includes threepiers35 that are each secured to a hub area, at equal spaced intervals and equal radial distances from the lower pulley half center, and extend througharcuate openings30 that are formed through theupper pulley half23a hub area. Thepiers35 each include arod36 extending axially from the top surface, that, in turn, are each fitted throughholes37 formed through theactuator cover plate21. Theholes37, as shown inFIG. 3, are each stepped outwardly intoflat ledge37a, and therod36 ends are stepped inwardly into a flat shoulder. So arranged, each rod shoulder fits against a hole ledge, and a rod end that extends through thehole37 is threaded to receivenut38 turned thereover, for mounting theactuator cover plate21 ontorods36, as shown inFIGS. 1 and 2. Theactuator cover plate21 also includes acenter hole28 wherein abushing27 is shown fitted. Thebushing27 is to support travel of a straightcylindrical shaft26 between the attitudes shown inFIGS. 1 and 2. As shown, the straightcylindrical shaft26 extends, at a right angle from theactuator cover plate21undersurface22, and is fitted through a center hole of thepulley23. Thecylindrical shaft26 is secured to theupper pulley half23a to slide through thelower pulley half23b.

Thecylindrical shaft26, as set out above fitted through thecenter bushing27 is maintained incenter hole28 formed through theactuator cover plate21 to allow the cylindrical shaft to turn or pivot relative to theactuator cover plate21 duringactuator device20 operation. This allows foractuator cover plate21 pivoting or turning between the attitudes shown inFIGS. 1 and 2.

Movement of theactuator cover plate21 towards theupper pulley half23atop face24 is transferred through the connectingrods36 andpiers35 to thelower pulley half23b so as to move thepulley23 halves apart, spreading the pulley V. As shown inFIG. 2, eachconnector rod36 is spaced away from the center of thelower pulley half23b and projects through an opening formed in theupper pulley half23a. While theactuator cover plate21 ofFIGS. 1 through 3, appears to be like and to function like the actuator cover plate of my earlier cited U.S. Patent Application, it should be understood thatrollers51, as shown best inFIG. 5, are unique and distinct as set out and described hereinbelow.

In both the present and my earlier U.S. patent application the actuator cover plate is moved towards theupper pulley half23atop face24. To provide for actuator cover plate and lower pulley half movement, the present invention and my earlier U.S. patent application both include the radial equally spacedparallel piers35 that are each secured to extend at right angles upwardly from the hub area of the lower pulley have23b, and pass througharcuate holes30 formed in theupper pulley half23a. Thepiers35 each include the smooth walledcylindrical rod36 that extends axially from each pier top end. Thecylindrical rods36 are to fit through that holes37 that are formed at radial spaced intervals through theactuator cover plate21, as shown best in FIG.2. So arranged, theactuator cover plate21 is maintained to thelower pulley half23b and will slide up and down alongcylindrical shaft26 pivoting or turning relative to thecylindrical shaft26, when traveling between the attitudes shown inFIGS. 1 and 2, to open thepulley23, as described above.

With theactuator cover plate21 secured onto each of theconnected rods36, as set out above, acoil spring39 is provided to bias theactuator cover plate21 outwardly, as shown in FIG.1. To provide for the pulley halves23a and23b being normally closed together, thecoil spring39 is disposed around thecylindrical hub26. So arranged, the ends ofcoil spring39 engage, respectively, theundersurface22 of theactuator cover plate21 and thetop face24 of theupper pulley half23a. Thecoil spring39 thereby urges theactuator cover plate21 outwardly to where the halves ofpulley23 are closed together, as shown in FIG.1. The biasing ofcoil spring39 is overcome to urge the actuator cover plate towards the upper pulley half, spreading the pulley23 V, as shown in FIG.2.

My cited U.S. Patent Application, and theactuation devices20 and70 of the invention all preferably employ a helix or cam cone whereon are formed cam tracks that are each for guiding cam followers. A helix orcam cone40 of the actuator device is shown best in FIG.4 and as sections inFIGS. 4A,4B,4C,5,5A and5B with a helix orcam cone77 of theactuation device70 shown best inFIG. 9, both having been removed from their mounting, respectively, to the top orupper face24 of thepulley half23a and a hub ofpulley half72.

Each helix orcam cone40, shown inFIGS. 4 and 6, and72 shown inFIGS. 7 and 9, is preferably formed from a metal cylinder wherefrom sections of material are removed to leave for the helix orcam cone40, abase ring41 that includes a flat bottom surface and a mounting slot, respectively. Thebase ring41 is stepped outwardly at equal radial points along a top surface thereof into spacedplatforms42 wherein are formedstraight bolt hole43 that extend therethrough. The bolt holes43 are each to receive abolt44, shown inFIGS. 1 and 2, fitted therethrough. Thebolts44 are turned into holes, not shown, that have been formed in the upper ortop face24 of theupper pulley half23a, mounting the helix orcam cone40 thereto. Adjacent to eachplatform42, the helix or cam cone is stepped outwardly into acam section45 that, as shown best inFIGS. 4 and 6, is essentially a right triangle and includes astraight cam track46 as the right triangle hypotenuse side.

Eachcam track46 of theactuator device20 is flat between the edges thereof and in FIG.4 and is radiused at46c inFIG. 4A has acenter apex46d with downwardly slopingsides46e and46f extending therefrom to intersect cam track edges46a and46b inFIG. 4B, and shows, inFIG. 4C, the apex as having been milled, of otherwise formed, into aflat surface46g. Therespective track46 surfaces of4,4A,4B and4C to receive theroller51 of a camfollower roller bearing50 positioned for travel therealong. In this embodiment, each track is to receive a convex outer surface ofroller51 ofFIG. 5, or an apex51d of a surface ofroller51, as shown in broken lines inFIG. 5a, or a flattened apex51e of a surface ofroller51, shown in broken lines in FIG.5B. For which convex surface, the greatest diameter of cross section of theroller51 is to be positioned at the center of thecam track46 betweenedges46a and46b thereof, and is to travel along the cam track center as it rolls up and down therealong. Accordingly, the radius of the convex curved51c, apex51d or flattenedapex51c surface of eachroller51 preferably has a greatest diameter at theroller lateral center51c, shown in broken lines inFIGS. 3 and 5, with apex51d ad flattenedapex51e shown in broken lines inFIGS. 5A and 5B, respectively and curves or slopes uniformly therefrom to theroller51 ends51a and51b. It should be understood, however, that theroller51 greatest diameter can be at a location therealong other than thecenter51c, within the scope of this disclosure. The determination of the preferred location of the roller surfacegreatest diameter51c,51d or51e, is to position it betweentrack46 inner andouter edges46a and46b, respectively, to provide a path of travel of aroller51 of a cam follower bearing50 that will remain centered on thecam track46 along its entire path of travel. For the center of roller travel along the length oftrack46 to be equidistant from the cam track edges46a and46b, the radius of the helix orcam cone41 and theroller51 are selected such that aroller51 an appropriate radius of curvature is provided for the roller surface taking into account the varied cam angles that the cam follower roller will experience as it travels therealong.

For theactuation device20, the selection of a surface radius for theroller51 convex curve is based on thecam track46 slope that, of course, is also a helical curve that follows the curve of the helix orcam cone40. Thecam track46 may be formed to have from a thirty degree (30°) to seventy degree (70°) slope and that slope may itself vary along the track length. Shown herein, thetrack46 has approximately a fifty degree (50°) slope. For which slope a radius of curvature of theroller51 surface of approximately one (1) inch was selected for a track width of 0.325 inches and less, thereby producing, at theroller51center51c, an arc with a width of 0.26 inches and a drop of 0.0089 inches from the roller center to itsends51a and51b. This drop of 0.0089 inches is preferred for any cam track slope as set out above, with theroller51 radius to be selected accordingly.

As set out above, as an alternative arrangement to theactuation device20, theroller51 surface can be formed to have opposing equal flat sloping sides that slope together at an apex51d or flattenedapex51e, as along theroller center51c. Like the selection, as set out above, of the radius for a particular slope oftrack46, taking into account that the track is also a helical curve, the slope ofroller51 sides is selected to provide an apex51d or flattenedapex51e at theroller51center51c, or at a location thereacross, such that theroller51 will roll smoothly along thetrack46 center line duringactuation device20 operation. Accordingly, for theactuation device20, it should be understood that theindividual rollers51 surfaces can be radiused or can be formed with opposing sloping sides that meet in apex, or the like, as described. A roller contact surface is thereby provided to center the roller along the cam track length precluding application of side loads on thecam roller bearing50 throughroller51 as it travels therealong.

For theactuation device20, each cam follower bearing50 that includes theroller51, as shown best inFIGS. 3 and 5 and described above, is shown as mounted on to ashaft54. Eachshaft54 is fitted through each of threeposts52 that extend at right angles outwardly at equidistance radial distance intervals from one another around the center of theundersurface22 of theactuator cover plate21. Eachpost52, as shown, is preferably formed at a flat section having a regular pyramid profile is connected to the actuator cover plate undersurface along its base and has a rounded apex that includes ahole53 formed therethrough, as shown best inFIG. 5, that receives ashaft54 fitted therethrough. Eachshaft54 preferably includes a broad flathead end55, and is press fitted throughhole53 throughpost52 to receive aconnector56 fitted thereover. Theshaft54 is part of the cam follower bearing50, that includesroller51 and is journaled to turn freely on the sealedneedle bearing58, as shown in broken lines in FIG.5.

As set out above, and as shown inFIGS. 3 and 5, theroller51 curved surface will travel up and down alongcam track46, following a center path therealong. Theroller51 is at rest at approximately the top ofcam track46. Duringactuation device20 operation, to spread apart the pulley halves23a and23b as shown inFIG. 2, as the roller descends along thecam track46 each cam track top end, that is the apex end of eachcam section45, will pass through one of three arcuate slots47 that have been formed through theactuator cover plate21. The arcuate slots47 are spaced equidistantly apart and are at equal radial distances from the actuator cover plate center. Thecam sections45 are to retract through the arcuate slots47 when pressure to move theactuator cover plate21undersurface22 towards theface24 of theupper pulley half23a is released. Thecoil spring39 is provided to return theactuator cover plate21 to the attitude shown in FIG.1.

The second embodiment of theactuation device70 is shown inFIGS. 7 through 9 and9A. Similar toactuation device20, inFIG. 7, theactuation device70 is shown to include apulley71 having lower and upper pulley halves72 and73, respectively. Like the lower and upper pulley halves23a and23b of theactuator device20, the pulley is to receive a drive belt, not shown, fitted therebetween. With, upon operation of theactuation device70, the surfaces of the pulley halves will move apart and back towards one another changing the pulley radius that the belt turns around. This provides, like theactuation device20, for a smooth shifting upon torque sensing, functioning essentially like theactuation device20.

Acylindrical shaft74 is mounted axially to extend upwardly from the center of thelower pulley half73 to pass through a larger center opening75 that is formed through theupper pulley half73 hub area. Pulley hub opening75 includes a plurality of straightpointed fingers76 that, as set out below, are each for fitting into one ofslots83 formed in a helix orcam cone77. Acoil spring78 is shown aligned for fitting in thehub opening75 in theupper pulley half73 fitted around thecylindrical shaft74. With atop end78a ofcoil spring78 for engaging the undersurface of acylindrical bearing carrier79. InFIGS. 7 and 9, the helix orcam cone77 is shown to include alip80 that is formed around the lower end thereof adjacent to agroove81 formed around the lower portion thereof. Thelip80 is for fitting, as shown best inFIG. 7, withinhub opening75, of theupper pulley half73. With thefinger76 to fit the helix orcam cone77slots83. Thecam cone77 is thereby mounted at a right or normal angle from the top surface of theupper pulley half73. Thecoil spring78 is for fitting therethrough and for engaging a lower end ofcylindrical bearing carrier79, as set out hereinbelow.

Like the above described helix orcam cone40 of the first embodiment, the helix orcam cone77, as shown best inFIG. 9, includes a plurality of cam tracks84, shown herein as three tracks. Like the cam tracks46, the cam tracks84 are each of the hypotenuse side of a right triangle, with aside85 thereof shown as vertical and the base the cross section extending between the lower ends of whichvertical side85 and thehypotenuse side84. As shown inFIGS. 7 and 9, the helix orcam cone77 is preferably formed from a cylinder that is machined appropriately to form the respective hypotenuse andvertical sides84 and85, as set out above. For this embodiment, as shown inFIG. 9A, the track surfaces84 are preferably each radiused, the curvature of which surface is like that set out in applicant's earlier patent application, and is computed, as described above for the radiusing therollers51 for theactuation device20. The track surfaces84 of theactuation device70, as set out and described above, provide for maintaining a bearing roller centered during travel therealong.

Thetracks84 are to receiverollers95 ofbearings94 of thecylindrical bearing carrier79, as shown in FIGS.7 and that will therealong. The cylindrical bearing carrier, as shown,8, is preferably an arrangement of anouter cylinders86 and aninner cylinder87 respectively, that are connected bystrut sections88. Thestrut sections88 connect into ashelf89 that extends at a right angle from theinner cylinder87, as shown best inFIGS. 8 and 9. A plurality of spacedholes90 are formed in theshelf89, as needed, for receivingtop end78a ofcoil spring78 fitted therein, with the oppositecoil spring end78b for fitting into a hole formed in the hub area of theupper pulley half73, not shown. Theinner cylinder87 is open therethrough at91, and includes alongitudinal keyway92 formed along its length. Curved arcuatelongitudinal openings93 are provided between the opposing surfaces of the outer andinner cylinders86 and87 that accommodate thetracks84 of the helix orcam cone77. Theopenings93 accommodate the helix orcam cone77tracks84 as the move up and down therein, in whichmovement rollers95 ofbearings94 engage and roll along the respective track surfaces84.

Thebearings94, as shown, are mounted between the inner andouter sleeves87 and86, respectively, each on ashaft96, that is shown in broken lines in FIG.8.Split ring97 andwasher98 are provide for fitting into atop groove74b, thesplit ring97 to hold thewasher98 against the top surface of theinner cylinder87 and with the bottom of the inner cylinder connected to thecoil spring78, as set out above. Thecylindrical bearing carrier79 is secured onto thecylindrical shaft74. To prevent cylindrical bearing carrier pivoting a key, not shown, is fitted between intokeyway74a that is formed in thecylindrical shaft74, and thekeyway92, prohibiting rotation. So arranged, the vertical movement of thecylindrical bearing carrier79 moves also thelower pulley half72 against the biasing ofspring78. Thereby, theroller95 orbearings94 traveling down the slopingtracks84, moving the respective pulley halves72 and73 apart. With movement of thecylindrical bearing carrier79 upwardly, causing thebearing94rollers95 to travel upwardly along thetracks84, moving the respective pulley halves together.

As set out above, thecylindrical bearing carrier79 mounts onto the end ofcylindrical shaft74 such that, when the assembly is moved, by the bearing94roller95 traveling along thetracks84, thecylindrical shaft74 will be moved also. The pulley halves72 and73 are thereby separated or brought together, functioning as described hereinabove with respect to the discussion ofFIGS. 1 and 2.

In practice, a depression of thecylindrical bearing carrier79, against the biasing ofcoil spring78, will cause therollers95 ofbearings94 to travel down thetracks84, acting through on thecylindrical shaft74 to spread apart the pulley halves72 and73. Whereas, when a pressure is released from off thecylindrical bearing carrier79 thecoil spring78 acts to move therollers95 of thebearings94 back up thetracks84, returning the pulley halves72 and73 to the attitude shown in FIG.1.

Actuation devices20 and70, as wet out hereinabove, include, respectively, radiused configurations ofroller51 surface and a radiusing oftracks84, respectively. In each of these configurations the opposing surface to the roller or track is flat. Accordingly, it should be understood that the invention is in any torque responsive device that provides for travel of opposing surfaces over one another to effect operation thereof, where one of those opposing surfaces is radiused and the other is flat. Accordingly, it should be understood that the invention is not limited to a particular actuation device, as shown and described herein, and includes any torque responsive device where one of the opposing track and bearing surfaces is radiused, within the scope of this disclosure.

While preferred embodiments of my invention in torque responsive actuation devices for a belt drive system have been shown and described herein, it should be understood that the present disclosure is made by way of example only and the invention is suitable for a number of uses, including, but not limited to, a use as a snowmobile clutch system, and the like, and that variations and changes to the torque responsive actuation device as described are possible without departing from the subject matter coming within the scope of the following claims, and a reasonable equivalency thereof, which claims I regard as my invention.

Claims (7)

1. A torque responsive actuation device comprising, a split pulley having a pair of upper and lower pulley halves forming a V slot therebetween to receive a drive belt; a cylindrical cam cone means maintained to extend outwardly from a center of a top face of said upper pulley half and including a plurality of equally spaced identical right triangle cam sections each including a like sloping cam track that extends along said right triangle hypotenuse side; a shaft means extending from said lower pulley half; a carrier means whereto are arranged a plurality of cam follower means that each include a roller bearing means for each said sloping cam track, with said carrier means maintained through a connector means to said lower pulley half, said connector means including a plurality of connectors spaced from a center of said lower pulley half and projecting through an opening formed in said upper pulley half, and each said cam follower means and roller bearing means includes a roller journaled thereto having a surface that contacts one of said sloping cam tracks, to roll therealong, and either said roller contact surface or said sloping cam track surface is radiused or crested, to be equally curved or sloped downwardly from a highest point or surface of each said sloping cam track to the sides of each said right triangle cam section; and spring biasing means for urging said carrier means away from said upper pulley half top face.

2. A torque responsive actuation device for a belt drive system as recited inclaim 1, wherein either the roller contact surface or the sloping cam track surface is formed with a convex surface between said roller sides or said cam track sides to have a radius selected for the cylindrical cam cone cam track slope.

3. A torque responsive actuation device as recited inclaim 2, wherein either the roller contact surface or the sloping cam track surface is formed to have a center apex therearound or therealong wherefrom two like, oppositely sloping, flat surfaces slope to the roller sides or the sloping cam track surface sides.

4. A torque responsive actuation device as recited inclaim 1, wherein the shaft means is a straight cylindrical shaft connected at its lower end to the pulley lower half, passes through the pulley upper half and connects, at its upper end to the carrier means; and the spring biasing means is a coil spring disposed around said straight cylindrical shaft between said upper pulley half and said carrier means.

5. A torque responsive actuation device as recited inclaim 1, wherein the means for connecting the carrier means to the lower pulley half are a plurality of equally spaced piers that each include rods extending axially out of top ends thereof, which said piers are each secured, at their lower ends, to said lower pulley half hub, are each radially equidistant from the center of said lower pulley half and will project at right angles through holes formed in the upper pulley half, with ends of said rods secured to said carrier means at approximately right angles to the undersurface thereof.

6. A torque responsive actuation device for a belt drive system as recited inclaim 1, further including spaced holes formed through the carrier means that are identical arcuate slots, are spaced equally from one another, at equal radial distances from the carrier means and are aligned for receiving the right triangle cam sections fitted therein.

7. A torque responsive actuation device as recited inclaim 1, wherein the cylindrical cam cone is formed to have a bottom portion for securing to the top face of the upper pulley half.

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