WO1996021577A1

WO1996021577A1 - Trailing arm suspension with locking mechanism

Info

Publication number: WO1996021577A1
Application number: PCT/US1995/000451
Authority: WO
Inventors: Steven M. Stojic
Original assignee: Nai Neway, Inc.
Priority date: 1995-01-12
Filing date: 1995-01-12
Publication date: 1996-07-18
Also published as: AU1679295A

Abstract

A locking mechanism for trailers comprising a rotatable member mounted to the trailer frame and adapted to be movable between a retracted position and an extended position. In the retracted position, the axle and wheel of the trailer are free to move within the limits of the suspension. In the extended position, the rotatable member limits the relative movement between the trailer frame and the suspension to limit creep of the trailer.

Description

TRAILING ARM SUSPENSION WITH LOCKING MECHANISM

Background of the Invention Field of the Invention

The invention relates to trailing arm suspensions and more specifically to a trailing arm suspension with a device for limiting the relative downward movement of a trailer frame with respect to the axle of a trailer during loading to minimize "creep" of the trailer from a loading dock or parked position. Description of the Prior Art

In order to load a commercial trailer from a rear door, the operator typically backs the trailer up against a dock, then lowers the front dolly legs on the trailer until they touch the ground, and removes the tractor. In storage conditions the tractor may or may not be connected to the trailer. Many trailers have trailing arm suspensions with air springs to control the relative position of the frame with respect to an axle and also to cushion the relative movement of the axle toward the frame due to bumps in the road. Although the air spring is pressurized by the tractor's air compressor during normal operation, the air compressor is normally off during loading operation.

As the trailer is loaded, the force from the weight of the goods loaded into the trailer and the loading equipment, such as a forklift or a handcar, lowers the rear portion of the frame rail with respect to the axle. Because the compressor is off during the loading operation, the air pressure in the air spring is not adjusted to compensate for the increased load. While the rear portion of the trailer frame moves downwardly, the front portion of the trailer frame is substantially fixed at the height of the dolly and the trailer frame effectively rotates about the contact point of the dolly with the ground. The downward movement of the rear portion of the trailer frame results in the pivotable movement of the pivotal connection between the trailer frame and the trailing arm. This pivotable movement results in the slight rotation of the trailing arm wheel to move the trailer forward away from the dock. In other words, the trailer tends to move away from the loading dock. This movement is referred to as "creep." Creeping of the trailer can create hazards for loading of the trailers. U.S. Patent No. 5,333,645, issued August 2, 1994, discloses an apparatus for overcoming this problem by providing a dump valve to exhaust air from the air spring when the trailer door is opened. The trailer thus bottoms out on the suspension before loading begins and cannot creep away from the dock. Whereas this system has worked well to prevent creep, not all vehicles are equipped with this system, or cannot use such a system. Also, the door switch sometimes malfunctions and the dump valve does not always exhaust air from the air spring.

Therefore, there is a significant need to reduce or eliminate the creep associated with a trailer during loading. The anti-creep solution must also be simple, reliable and inexpensive if it is to be commercially viable. Further, the anti-creep solution must also not interfere with the normal function of the trailing arm suspension during normal operation thereof.

Summary of Invention The invention relates to a suspension with an anti-creep device for locking the relative movement of a trailer with respect to the suspension. It is simple, convenient and effective, and does not interfere with the normal operation of the trailing arm suspension during normal operation of the trailer. The anti-creep device is adapted for use in a trailing arm suspension comprising a trailing arm rotatably mounted at one of its ends to a trailer frame. At another end of the trailing arm, an air spring is disposed between the trailing arm and the trailer frame to resiliently resist the upward movement of the trailing arm with respect to the frame. An axle is mounted to the trailing arm and mounts a wheel. The anti-creep device comprises a telescoping rod and cylinder, which are mounted at one end to the trailing arm of the suspension and adapted to be mounted to the vehicle at the other end. The rod is ordinarily free to slide within the cylinder. A lock is mounted in the cylinder for locking the position of the rod in the cylinder. A pressure-responsive actuator is positioned in the cylinder and selectively actuates the lock to lock the rod and the cylinder so as to prevent the telescoping movement of the rod within the cylinder. Preferably, the lock is a mechanical lock. In another embodiment, the invention relates to an anti-creep device for a trailing arm suspension comprising a telescoping rod and cylinder with a lock mounted with a cylinder and a pressure-sensitive actuator to selectively actuate the lock. Brief Description of the Drawings

The invention will now be described with reference to the drawings wherein:

FIG. 1 is a side elevational view of a trailing arm suspension incorporating a locking mechanism according to the invention; FIG. 2 is an enlarged partial sectional view of the locking mechanism of FIG. 1 in an unlocked position;

FIG. 3 is a sectional view along line 3-3 of FIG. 2;

FIG. 4 is an enlarged partial sectional view of a second embodiment of the locking mechanism according to the invention; FIG. 5 is a sectional view along line 5-5 of FIG. 4;

FIG. 6 is a sectional view along line 6-6 of FIG. 4; and

FIG. 7 is an enlarged partial sectional view along line 7-7 of FIG. 5.

Description of the Preferred Embodiments Figure 1 illustrates a trailing arm suspension 10 incorporating a locking mechanism 12 according to the invention. The trailing arm suspension 10 is mounted to a longitudinal frame rail 14 of a trailer frame and supports an axle 16 to which wheels 18 are mounted on opposite ends of the axle 16. In a typical trailer application, two trailing arms are used to mount the axle 16 to the frame rail 14. The trailing arms are mounted on opposite sides of the frame rail and support opposing ends of the axle 16. Only one of the trailing arms will be described in detail.

The trailing arm suspension 10 comprises a hanger bracket 22 fixedly mounted to the frame rail 14 and to which is rotatably mounted a trailing arm 24 by means of a bushed connection 26 at the forward end of the trailing arm 24. The rearward end of the trailing arm 24 mounts an air spring 30 at a lower end thereof, which is connected to the frame rail 14 at its upper end. The air spring 30 resiliently resists upward movement of the trailing arm 24 with respect to the frame and comprises an air bag 32 mounted to the frame rail 14 by a plate 36 and a piston 34 mounted to a platform 38 on the trailing edge of the trailing arm 24. As the trailing arm 24 rotates, the piston 34 is urged into the air bag 32 to resiliently retard movement of the trailing arm 24 toward the frame rail 14.

The axle 16 is mounted to the trailing arm 24 by an axle mounting bracket 40 having opposing plates 42, which are connected to the trailing arm 24 through two bushed connections 44 and 46. A shock absorber (not shown) can be mounted between the frame rail 14 and the axle bracket

40 to dampen the movement of the trailing arm 24 with respect to the frame.

Referring to FIGS. 2-3 specifically and FIG. 1 generally, the locking mechanism 12 comprises a rod 60 and housing 62 in which the rod 60 is received for reciprocal movement with respect thereto. The rod 60 and the housing 62 are pivotally mounted to the frame rail 14 and the end of the trailing arm 24 by pivot pins 64, 66, respectively. Preferably, the rod 60 has a constant diameter and is made from steel.

The housing 62 comprises a base 70 and top or cover 76. The base 70 is generally a cylindrical tube with a cylindrical sidewall 80 having a closed bottom 82 and an open top. The sidewall 80 has an inner surface 88 comprising a converging diameter portion, defined by camming surface 92, and a constant diameter portion, defined by an cylindrical surface 96. The inner surface 88, bottom 82 and top or cover 76 define a housing chamber 100 in which is received a locking taper 72. The cover 76 comprises a top wall 152 from which extends an cylindrical sidewall 154. An aperture 156 for receiving the rod 60 is positioned in the top wall 152. A spring means 74 is positioned between the locking taper 72 and the top 76 to urge the locking taper 72 axially within the housing chamber 100.

Extending from the bottom 82 of the base 70 is a clevis 102, which has an aperture 104 in which is received the pivot pin 66. An air inlet/exhaust port 106 extends from the locking taper chamber 100 through the bottom 82 of the base to a pressurized air source fitting 108. A source of pressurized air, preferably the spring brake air supply, is connected to the pressurized air source fitting 108 so that pressurized air can be directed into the locking taper chamber 100 through the air inlet/exhaust port 106.

The locking taper 72 comprises a locking taper piston 116 from which extend multiple tines 144. Each tine 144 has a head 145 connected to the piston 116 by a stem 147. A sealing means, such as an O-ring 117, is disposed about the locking taper piston 116 and seals it with respect to the inner surface 88 of the sidewall 80 and divides the housing chamber 100 into two portions. The portion of the housing chamber 100 between the base 82 and the locking taper piston 116 defines a pressure chamber, which can be pressurized by the pressurized air entering the inlet/outlet port 106.

The multiple tines 144 form an outer surface 120, which generally conforms to the inner surface 88 of the base 70. That is, the outer surface 120 has a slanted surface 122 and cylindrical surface 124, which correspond to the camming surface 92 and cylindrical surface 96, respectively. The tines 144 also form an inner surface 128 comprising a face

130 having a reduced diameter and cylindrical surface 132 having a diameter greater than the diameter of the face 130. A beveled surface 133 connects the face and cylindrical surfaces 130, 132. The inner surface 128 and the locking taper piston 116 define a rod chamber 134 in which the end of the rod 60 is received. The open top 118 of the locking taper 72 has an cylindrical flat 138 from which extends an cylindrical stop rib 140.

The tines 144 can be categorized into two groups: outwardly sprung tines 146 and inwardly sprung tines 148. The outwardly sprung tines 146 are bent outwardly from their normal or unsprung position. Similarly, the inwardly sprung tines 148 are bent inwardly from their normal or unsprung position. In their normal or unsprung position, the tines 144 are aligned as are th'. ir respective portions of the face 130, cylindrical surface 132, beveled surface 134 and inner surface 128.

To assemble the locking mechanism 12, the locking taper 72 is inserted into the locking taper chamber 100 of the base 70 until the slanted surfaces 122 of the outwardly sprung tines 146 abut the camming surface 92 of the base 70. The spring 74 is positioned on the cylindrical flat 138 of the locking taper 72 and the cover 76 is secured to the base 70 by welding the cover 76 to the base 70. Alternatively, the cover 76 and the base 70 can have complementary threads so that the cover 76 can be threaded onto the upper end of the base 70. Once the housing 62 is assembled, the rod 60 is inserted through the top wall aperture 156 and into the rod chamber 134. Preferably, there is sufficient room between the end of the rod 60 and the locking taper piston 116 of the locking taper 72 for the rod to reciprocate through a distance at least equal to the range of motion of the trailing arm suspension. In most situations, a four inch distance between the end of the rod 60 and the locking taper piston 116 is sufficient. During normal operation of the vehicle, the vehicle air system is pressurized to direct pressurized air through the air inlet/exhaust port 106 into the pressure chamber portion of the locking taper chamber 100 to exert a force against the locking taper piston 116 to axially move the locking taper within the locking taper chamber 100 until the cylindrical stop rib 140 contacts the top wall 152 of the cover 76. The locking taper 72 need only move an axial distance great enough to prevent firm contact between the beveled surface 122 and the camming surface 92. It is sufficient if the locking taper is raised a distance so that the camming surface 92 is not firmly seated on the slanted surface 122. In this position, the camming surface 92 does not exert a sufficient radially force on the head 145 of the outwardly sprung tines to urge their faces 130 into contact with the rod 60.

Preferably, the face 130 of the inwardly sprung tines 148 remains a sufficient distance from the rod 60 so that there is relatively no frictional engagement between the rod 60 and the face 130. If there is any frictional engagement between the rod 60 and the face 130 of the inwardly sprung tines

148, the force of the pressurized air supporting the locking taper 72 is great enough to overcome any downward movement of the locking taper 72 in response to any frictional engagement between the rod 60 and the locking taper 72. Once the vehicle has reached its destination, the pressurized air source for the trailer is typically uncoupled or shut off, thus, exhausting pressurized air from the air system. Upon the exhaustion of the pressurized air, the locking taper 72 is no longer supported and settles within the locking taper chamber 100. The spring 74 also urges the locking taper 72 down into the locking taper chamber 100 so the camming surfaces 92 of the outwardly sprung tines 146 seat on the slanted surface 122. As the locking taper 72 is urged by the spring into the locking taper chamber 100, the slanted surface 122 of the outwardly sprung tines 146 abuts the camming surface 92 to direct the outwardly sprung tines 146 toward the rod 60.

In this position, the faces 130 of the inwardly sprung tines 148 abut the rod 60. As the trailer is loaded, the rod 60 is urged downwardly into the rod chamber 134. As the rod 60 moves downwardly, it frictionally engages the face 130 of the inwardly sprung tines 148 and urges the locking taper 72 downwardly into the locking taper chamber 100. As the locking taper 72 is urged downwardly by the frictional engagement between the rod 60 and the faces 130 of the inwardly sprung tines 148, the slanted surfaces 122 of the locking taper 72 and the camming surface 92 of the base 70 direct the outwardly sprung tines 146 radially inwardly toward the rod 60, until the faces 130 of the outwardly sprung tines 146 frictionally engage the rod 60, in a manner similar to the faces 130 of the inwardly sprung tines 148. When the faces 130 of the inwardly sprung tines 148 and the outwardly sprung tines 146 frictionally engage the rod 60, the rod is locked from further movement in response to the loading of the trailer. Typically, the rod 60 will lock after approximately one-half inch of travel.

After the rod is locked by the locking taper 72, the trailer can be loaded without any more relative movement between the frame rail 14 and the trailing arm 24. Therefore, the creep of the trailer is prevented after the rod is locked by the locking taper 72.

FIGS. 4-7 illustrate a second embodiment of the locking mechanism 200 according to the invention. Referring to FIG. 4, the locking mechanism 200 comprises a rod 202 and a housing 204. The rod is received within the housing 204 and reciprocally moves with respect to the housing 204. Both the rod 202 and the housing 204 are pivotally connected to the frame rail 12 and the trailing arm 24 by pivot pins. Only one of the pivot pins 208 is shown. A circumferential groove 210 is formed in the rod 202 adjacent a terminal end 212. The housing 204 comprises a base 220, piston 222, and cover 224. The base 220 comprises a cylindrical sidewall 230, a closed bottom 232 and an open top 234. The sidewall 230 has an inner surface 236 in which a plurality of radially extending grooves 238 are formed therein and are preferably spaced 45 ^* apart about the inner circumference of the sidewall 230.

A rod chamber 240 is defined by the inner surface 236, closed bottom 232 and open top 234. An air inlet/exhaust port 242 extends from the rod chamber 240 through the closed bottom 232 to a pressurized air source fitting 244. The base further comprises a clevis 246 having an aperture 248 through which the pivot pin 208 passes to pivotally mount the housing 204 to the trailing arm 24.

Near the open top 234 of the housing 204, there is a camming surface formed by multiple, spaced ramped surfaces 252 (FIG. 7) and arcuate surfaces 254. The ramped surfaces 252 are formed in the sidewall 230. Immediately below the ramped surfaces 252 are the arcuate surfaces 254 having a generally arcuate cross section. Also, the sidewall 230 is threaded at 256. Preferably, the ramped surfaces and arcuate surfaces 254 are spaced 15 ° apart about the sidewall 230 and positioned above the grooves 238. Although the camming surface is illustrated as discrete sections, it is within the scope of the invention for the camming surface to be continuous about the interior of the sidewall 230.

The cover 224 comprises a body 274 from which an cylindrical lip 276 extends longitudinally therefrom. The inner surface of the lip 276 is threaded and threadably engages the threads 256 of the housing 204. An cylindrical channel 278 is formed in the cover 224 by cylindrical walls 290, 292 and is disposed radially inwardly from the lip 276. The cylindrical wall 292 has an arcuate-shaped edge 294, which generally conforms to the contour of a roller 272, such as a bearing or a pin, which is supported in the channel 278 by the piston 222. Coil springs 280 are positioned within the annular channel 278.

Although illustrated as multiple springs 280, multiple discrete springs or a single continuous spring extending throughout the annular channel 278 can be used. If multiple discrete springs are used, a separate spring must be positioned directly above each of the rollers 272. The springs 280 are positioned above each groove 238 and bias a ring 300, against the rollers 272.

The cover 224 also has a centrally disposed aperture defined by a circumferential wall 284. An cylindrical channel 286 is formed in the circumferential wall 284 and receives a wear band 288 made from a plastic or other suitable material.

Referring to FIGS. 4 and 5, the piston 222 has a piston base 260 in which an cylindrical groove 262 is formed and which receives an O-ring 264. The O-ring 264 seals the piston base 260 with respect to the chamber 240 and divides the chamber into two portions. The portion of the rod chamber 240 below the piston base 260 defines a pressure chamber, which is pressurized by pressurized air entering through the inlet/outlet port. Multiple tines 268 extend radially from the piston base 260. The tines are spaced about the circumference of the piston base 260 to conform and in registry with the grooves 234.

To assemble the locking mechanism 200, the piston 222 is oriented with respect to the rod chamber 240 of the housing 204 so that the tines 268 align with the grooves 238. The piston 222 is then inserted into the rod chamber 240. The rollers 272 are positioned on the tines 268. When the rollers 272 are properly positioned, the cover 224 is threaded onto the housing

204. Finally, the rod 202 is inserted into and through the central aperture 282 of the cover and extends into the rod chamber 240. During normal operation of the vehicle, pressurized air is directed into the rod chamber 240 through the air inlet/exhaust port 242 and urges the piston 222 upwardly until the rollers 272 contact the cover 224. In this position, the O-ring 264 is positioned just below the grooves 238 of the housing 204 so that the portion of the rod chamber 240 below the piston 222 remains fluidly sealed with respect to the rest of the rod chamber 240.

When the piston is in the raised position, the rollers are retained between the cylindrical wall 292 of the cover and the upper end of the tine

268. The rollers do not extend a substantial distance beyond the inner surface 236 of the rod chamber 240 and, thus, do not interfere with the reciprocating movement of the rod 202 within the rod chamber 240. When the air pressure is exhausted, the piston 222 settles within the rod chamber 240 until it contacts the closed bottom 232 of the housing base 220. Typically, the piston 222 has a range of motion of approximately 1/4". As the piston 222 settles, the rollers 272 move downwardly until they contact the ramped cylindrical surface. Upon contacting the ramped cylindrical surface, the rollers 272 are directed radially inwardly until they contact the rod 202. As the trailer is loaded, the rod 202 moves downwardly within the rod chamber 240. Upon the downward movement of the rod 202, the circumferential groove 210 of the rod encounters the downwardly biased rollers 272. The rollers 272 are then directed by the spring 280 and the ramped cylindrical surface 252 into the circumferential groove 210. Further downward movement of the rod 202 by gravity results in the roller being carried by the rod into the arcuate surface 254. When the roller settles within the arcuate surface 254, the rod 202 is locked with respect to the housing 204, preventing subsequent downward movement of the rod 202 and, thus, preventing further creeping of the trailer.

In the normal operating position, pressurized air is directed into the pressure chamber to move upwardly the piston 222, tines 268, and, thus, the rollers 272, until the rollers 272 abut the ring 300. In this position a portion of the rollers abut the wall 292 and are raised above the camming surface 272 from moving radially toward the rod 202. Therefore, the rollers are prevented from engaging the groove 210 and the rod 202 is free to reciprocate within the housing.

The locking mechanism according to the invention provides a simple and reliable solution to the trailer creep problem. The locking mechanism also can be installed as original equipment or a retro-fit.

While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. Reasonable variation and modification are possible within the scope of the foregoing disclosure of the invention without departing from the spirit of the invention.

Claims

ClaimsThe embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a trailing arm suspension for a vehicle wherein a trailing arm is adapted to be pivotably mounted to a vehicle frame for swinging movement relative thereto, an air spring is mounted to the trailing arm and adapted to be mounted to the vehicle frame for resiliently resisting the rotation of the trailing arm toward the vehicle frame and an axle is mounted to the trailing arm, and an anti-creep device is mounted to the trailing arm to limit the rotation of the trailing arm toward a vehicle frame, the improvement comprising: the anti-creep device comprises: a telescoping rod and cylinder mounted to the trailing arm at one end and adapted to be mounted to a vehicle frame at another end, the rod being ordinarily freely slidable in the cylinder; a lock mounted in the cylinder for locking the position of the rod in the cylinder; and a pressure-responsive actuator in the cylinder to selectively actuate the lock to lock the rod in the cylinder to prevent the telescoping movement of the rod within the cylinder.

2. A suspension according to claim 1 wherein the lock is a mechanical lock.

3. A suspension according to claim 1 wherein the cylinder is a housing comprising a cylindrical wall, defining a hollow interior, a port in the wall for communication with a fluid source, and a camming surface on the wall within the interior, the rod being received within the interior in telescoping relationship to the housing for reciprocal movement relative thereto.

4. A suspension according to claim 3 wherein the lock comprises a retaining member mounted within the interior adjacent to the rod and movable radially and axially relative to the rod and the housing, the retaining member and circumferential wall at least partially defining a pressure chamber in communication with the port wherein the introduction of fluid thereto under pressure will impart axial motion of the retaining member in a first direction.

5. A suspension according to claim 4 wherein the actuator comprises a spring disposed within the housing to impart axial motion of the retaining member in a second direction, wherein upon release of pressure from the pressure chamber, the spring will urge the retaining member axially in the first direction and the camming surface will urge the retaining member radially against the rod whereby to lock the rod relative to the housing against further reciprocal movement.

6. A suspension according to claim 5 wherein the retaining member is a locking taper, the locking taper comprising: a base in abutting relationship with the circumferential wall to define the pressure chamber as the portion of the interior between the base and the closed bottom of the housing, and at least one tine extending from the base and positioned between the camming surface and the rod, the tine having a face disposed adjacent the rod and a beveled surface disposed adjacent the camming surface, whereby when the locking taper is moved axially and the beveled surface abuts the camming surface, the face is moved radially toward the rod to frictionally engage the rod and prevent reciprocal movement of the rod within the housing.

7. A suspension according to claim 6 wherein the tine has an upper surface connecting the face and the beveled surface and the spring abuts the upper surface to impart an axial force to the locking taper through the upper surface of the tine.

8. A suspension according to claim 7 wherein the housing is pivotally connected to the other of the frame and the suspension.

9. A suspension according to claim 8 wherein the housing comprises a base with an open top and a cover closing the open top of the base, and the cover has an aperture through which the rod extends into the interior.

10. A suspension according to claim 9 wherein the stop rib abuts the cover when the pressure chamber is pressurized to limit the axial movement of the locking taper within the housing.

11. A suspension according to claim 6 wherein there are multiple tines and their faces define an opening in which the rod is received.

12. A suspension according to claim 11 wherein the tines comprise radially outwardly disposed tines whose beveled surfaces are in contact with the camming surface but whose faces are not in contact with the rod and radially inwardly disposed tines whose faces are in contact with the rod but whose beveled surfaces are not in contact with the camming surface.

13. A suspension according to claim 12 wherein the outwardly disposed tines alternate with the inwardly disposed tines.

14. A suspension according to claim 5 wherein the circumferential wall has at least one slot formed therein with the slot being open to the interior and intersecting the camming surface, the rod has an cylindrical groove, the retaining member comprises a base in abutting relationship to the circumferential wall and from which extends at least one tine, the tine is disposed within the at least one slot and is disposed above the ramming surface when the base is in a first position and is disposed below the camming surface when the base is in a second position, and the retaining member further comprising at least one bearing positioned near the camming surface, whereby the bearing is prevented from moving along the camming surface when the base is in the first position and the bearing moves along the camming surface when the base is in the second position to seat within the cylindrical groove of the rod to lock reciprocal motion of the rod relative to the housing.

15. A suspension according to claim 14 wherein the camming surface is formed of multiple, discrete sections disposed about the interior and each camming surface section has a corresponding slot, tine and bearing.

16. A suspension according to claim 15 wherein the camming surface sections are evenly spaced about the circumferential wall.

17. A suspension according to claim 16 wherein the camming surface sections are radially spaced every 45 degrees.

18. A suspension according to claim 14 wherein the camming surface comprises a ramp portion and an arcuate portion and the ramp portion is disposed radially outwardly of the arcuate portion.

19. A suspension according to claim 18 wherein the shape of the arcuate portion generally conforms to the shape of the bearing.

20. A suspension according to claim 19 wherein the shape of the cylindrical groove generally conforms to the shape of the bearing and the bearing is received within the cylindrical groove and the arcuate portion to lock the reciprocal movement of the rod when the cylindrical groove and the arcuate portion are in alignment.

21. A suspension according to claim 14 wherein the top of the housing comprises an cylindrical flange against which the roller abuts when the tine is in the first position to prevent the roller from moving along the camming surface.

22. A suspension according to claim 21 wherein the cylindrical flange is arcuate in cross section and generally conforms to the shape of the bearing.

23. A suspension according to claim 22 wherein the top of the housing further comprises a recess for receiving the spring.

24. A suspension according to claim 23 wherein the recess is cylindrical and is disposed radially outwardly from the cylindrical flange.

25. A suspension according to claim 23 wherein the spring comprises multiple springs disposed about the cylindrical recess.

26. A suspension according to claim 23 wherein the spring is a singular cylindrical spring disposed within the recess.

27. A suspension according to claim 1 wherein the rod is of a constant diameter.

28. A suspension according to claim 1 wherein the rod is pivotally connected to one of the frame and the suspension.

29. A suspension according to claim 28 wherein the tine further comprises a stop rib extending from the upper surface of the tine.

30. An anti-creep device for a trailing arm suspension comprising: a telescoping rod and cylinder adapted to be mounted to the trailing arm at one end and adapted to be mounted to a vehicle frame at another end, the rod being ordinarily freely slidable in the cylinder; a lock mounted in the cylinder for locking the position of the rod in the cylinder; a pressure-responsive actuator in the cylinder to selectively lock the rod in the cylinder to prevent telescoping movement of the rod within the cylinder.

31. An anti-creep device according to claim 10 wherein the lock is a mechanical lock.