SUSPENSION OF REAR ARM WITH BRAKE ASSEMBLY ASSEMBLY CLAMP
BACKGROUND OF THE INVENTION Technical Field This invention relates to suspension systems for vehicles for mounting wheels that make ground contact to a vehicle frame and, more particularly, to rear arm suspensions having assembly axle assembly clamps. the axle to each arm and a brake assembly mounting bracket that couples the components of the brake system to the axle assembly mounting brackets. Description of Related Art Rear arm suspensions are well known and commonly used in heavy duty vehicle applications, such as semi-tractor / trailer configurations. A typical rear arm suspension comprises a pair of rear arm assemblies mounted on opposite sides of the tractor or trailer frame (referred to generically as the "vehicle") and carrying between them an axle that mounts wheels that make contact with earth. The rear arm assemblies are usually identical and comprise a rear arm pivotally mounted at one end to the vehicle frame, typically through the frame bracket, and resiliently connected to the vehicle frame along the arm, typically at another end, by means of an air spring to resiliently resist the pivotal movement of the rear arm relative to the frame. The axle is mounted on the rear arms between the pivotal connection to the frame bracket and the air spring or between the air spring and the other end of the arm. All rear arm suspensions are susceptible to bending moments induced by the vehicle's rolling, which can occur in response to the vehicle returning in a corner or one of the suspension sets changing height with respect to the other, such as running on a stool or falling into a hole. Either of these situations results in a tendency of the vehicle to rotate or "flip" around the longitudinal axis of the frame and thereby distribute the forces on the rear arm assemblies non-uniformly. This non-uniform distribution of forces on the rear arm assemblies tends to result in a vertical moment of bending on the axle if it is not absorbed or attenuated. The repeated application of the moment of bending induced by rolling on the shaft causes cyclic loading of the shaft and can contribute to shaft failure. In order to limit the moments of bending on the axle due to the rolling of the vehicle, it is desirable to relieve or attenuate the bending moments induced by rolling on the axle.
Historically, the solution to relieve bending induced moments by bearing falls into two categories, based on the type of rear arm: a flexible rear arm or a rigid rear arm. A flexible rear arm (also known as a spring beam) is made from one or more spring steel belts that are capable of undergoing resilient deflection, much like a spring, to relieve bending induced moments by rolling. The flexible beam is advantageous since the beam is flexed to relieve the vertical bending moments, not being important under normal circumstances the type of connection (resilient or rigid) between the flexible beam and the frame clamp and the shaft. The disadvantage of flexible beams is that they are typically heavier than rigid beams and in many cases are expensive to manufacture. Another approach to relieving vertical bending moments focuses on a rigid beam that is typically made by welding multiple plate steel elements together, usually in a box beam or I beam configuration. The rigid beam is advantageous over the flexible beam in that it has a substantially reduced weight and is much easier to form since only simple welding methods are required. The disadvantage of the rigid beam is that it can not be flexed or bent sufficiently to relieve the bending moments induced by rolling. Any moments of bending induced by bearing that reach the rigid beam are transferred to other components of the suspension, including the axis. The relief of bending induced moments by rolling should be directed to any other place in the suspension. For most rigid beam suspensions, both beam-to-frame connections (typically, the pivotal connection in the frame clamp) and shaft-to-beam (typically, a clamp that connects the shaft to the arms) are resilient to allow that the beam articulates with respect to the frame and that the shaft articulates with respect to the beam, respectively, to relieve the vertical bending moments induced by rolling. The resilient connection is usually achieved using a socket connector as disclosed, for example, in US Pat. 3,332,701; 3,140,880; 3,482,854; and 3,547,215. It has been common practice to weld the axles directly to the rear arm or to clamps that are mounted resiliently to the rear arms. Other components, such as radio rod towers and brake components, are typically welded to the shaft. Any welding on the shaft tends to form areas of weakness where cracks with repeated twisting or vertical loading are formed. The possibility of cracking in the welds is increased if the shaft is susceptible to vertical bending moments induced by rolling.
There have been many attempts to weld an axle directly to the beam or to an axle clamp in order to reduce weld failures on the axle due to vertical hoisting moments, induced by rolling, on the welds. US Patent No. 3,547,215, issued to Bird (issued December 15, 1970) discloses a rear arm suspension where a square shaft is typically welded to a clamp which, in turn, is secured to the rear arm of the frame of suspension of the vehicle. The weld that secures the shaft to the clamp is usually made at the midpoint of the shaft side where the neutrals are bending moment forces induced by rolling. However, these areas are loading areas that are the result of braking torsion, vehicle rolling and diagonal axis displacement (wheels), increasing the possibility of shaft failure. DE Nos. DE 42 32 779 and DE 42 32 778 disclose a vehicle suspension system with an air spring or leaf spring where a relatively square axle is tied in the suspension by means of a U-bolt and axle plate which supports against the shaft in an upper portion. A filler may be provided in the lower part of the U-bolt. A ring received in an opening in the shaft plate is welded to an upper surface of the shaft. It is said that the frictional force that results from the pressure applied by the shaft plate in the upper corners of the shaft and by the filler plate in the lower corners of the shaft coupled with the welded ring keeps the shaft against movement in the assembly . A U-bolt does not provide consistent and sufficient compression forces to adequately prevent the axle from skidding during assembly and does not work well with round axles. A solution to the problem of welding is disclosed in US Patent No. 4,693,486, issued to Pierce et al. (Issued September 15, 1987), which discloses that in a rear arm suspension in which an axle secured to an arm after a wrapping plate that partially surrounds the shaft, a bolt compresses the wrapping plate around the shaft so that the wrapping plate holds and strengthens the shaft, and a circular sealing weld is placed on the shaft in a circular opening in the wrapping plate to join the wrapping plate to the shaft. Although this system is a significant improvement over pre-shaft welds, the plug weld can still be a source of stress cracks in the shaft. It is also common to mount a rail bar between a rear arm and a central portion of an axle. The rail bar is mounted to the shaft by a tower clamp that is welded to a central portion of the shaft. The welds between the tower clamp and the shaft can introduce into the shaft weak points and microscopic cracks that can form sources of cracking that can ultimately result in shaft failure under prolonged or severe load conditions. US Patent No. 5,116,075, issued to Pierce (issued May 26, 1992), discloses a rear arm suspension where a wrapping plate is mounted on an axle by mechanical compression and, desirably, without welding to the axle. Adapter plates mounted on the ends of the plate apply a compressive force to the corners of a square shaft when the wrapping plate is compressed against the shaft by a bolt. The wrapping plate is mounted on a pair of side plates which in turn are fixed to the rear arm. Although the suspension is potentially effective in reducing the crack initiation potential of the shaft between the shaft and the shaft clamp, a considerable amount of skilled labor is involved in the assembly of the shaft to the rear arm suspension, frequently in the Assembly point of the axle and suspension to the vehicle. Compression forces tend to be somewhat uneven. TraditionallyS-cam brake assemblies have been mounted on the shaft, typically by welding to maintain proper alignment of the components of the brake assembly. Inboard welding of the rear arms can result in shaft-induced weaknesses in the weld which are susceptible to crack initiation as a result of cyclic loading, as described above. It would be desirable to avoid welding the brake components to the shaft to avoid weaknesses induced by unnecessary welding on the shaft. However, it is necessary to maintain absolute rigidity between at least the shaft and the S-cam bearing and desirably between the brake actuator and the shaft for the proper operation of the brakes. Any relative movement between the shaft and the S-cam bearing or between the shaft and the brake actuator can adversely affect the operation of the brakes. In this way, mounting the S-cam bearing and the brake actuator in the rear arm or beam in a typical joint-to-socket connection between the beam and the shaft has not been possible until now. U.S. Patent No. 5,366,237, issued to Dilling et al. Discloses a rear arm suspension in which a round shaft is opened in aperture in a pair of side plates in a rigid beam and welded to the side plates around the openings, resulting in a rigid connection from shaft to beam or arm. In one embodiment, a bushing extending the width of the rigid beam is mounted on the shaft and is welded to the shaft and side plates of the rigid beam. A special patented bushing must be used in the pivotal mounting between the rigid beam and the frame clamp to relieve the axle load due to the bearing of the vehicle. A brake actuator and an S-cam bearing are mounted directly on the rigid beam to operate brakes on the axle wheels. The rigid mounting of the shaft on the rigid beam uses the rigid beam and shaft so that the brake actuator and S-cam mount can be mounted directly to the rigid beam rather than to the shaft. Although the suspension of the patent? 237 by Dilling et al. Prevents the resilient coupling of the shaft with the rigid beam, and therefore allows the direct mounting of the brake components on the rigid beam, the suspension does not prevent the forces induced by the welding. on the shaft and in this way is subject to failure in the welds due to cyclic loading. In addition, the suspension of Dilling and collaborators requires a special patented bushing between the rigid beam and the frame clamp. In addition, the fracture of the shaft results in the disposal of the entire sub-assembly of rigid axle-beam due to the welding of the shaft to the rigid beam. A suspension system in which an axle is mounted on a rear arm through a wrap band that compresses the shaft without welding is disclosed in the international patent application No. PCT / US97 / 18733. In this application, the shaft is mounted on sets of relatively narrow wrapping bands that are held in tension by compressing the end portion of halves of the wrapping bands together and joining the halves together while compressed on the shaft. The assembly of the brake components in the wrapping bands and in the shaft clamps is also disclosed. SUMMARY OF THE INVENTION The invention relates to a vehicle suspension for mounting wheels that make contact with earth in a vehicle frame. The suspension system comprises a pair of rear arm assemblies, each of which is adapted to be mounted on a different side of the vehicle frame and comprises an arm. At least one wheel bearing shaft is mounted on each of the arms by an axle assembly assembly. A brake assembly clamp is mounted on the axle mounting assembly and mounts a brake actuator and a S-cam bearing. The axle assembly assembly may include at least one and preferably two hollow wrap bands connecting the shaft rigidly with one or more axle mounting plates which in turn are connected in a resilient manner to one of the arms. Preferably, the brake assembly clamp is mounted to the wrapping band. The brake assembly clamp is preferably mounted removably to the wrapping band, typically by bolts. In one embodiment, at least one axle mounting plate is resiliently connected to one of the arms and mounted rigidly on at least one wrapping band. The hollow wrapping band or bands have a width greater than a thickness and circumscribe the axis with internal surface portions configured to conform to at least a portion of at least two sets of diametrically opposed outer surfaces spaced circumferentially from the axis. The hollow wrapping band or bands are under sufficient tension to compress the shaft in each of the inner surface portions of the wrapping band and uniformly distribute a compressive load on the shaft through the at least two sets of surfaces Diametrically opposed external members of the shaft sufficiently to prevent relative movement of the shaft with respect to the wrapping band under ordinary service conditions. In one embodiment, each of the clamps of the brake assembly is rigidly connected to two wrapping bands. The clamp of the brake assembly preferably comprises a coupling portion that mounts the clamp of the brake assembly in the axle assembly assembly, a brake actuator mounting portion in which the brake actuator is mounted, and a portion of the S-cam bearing assembly in which the S-cam bearing is mounted. In one embodiment, the coupling portion is a plate, generally transverse to the axis, with an arcuate upper edge that partially circumscribes the axis. In another embodiment, the coupling portion is preferably connected to the arm by at least one, and preferably two, bushing connectors. The bushing connectors comprise an inner sleeve, an outer sleeve, and an elastomeric ring disposed between the inner and outer sleeves. The outer sleeve is rigidly connected to the arm, and the inner sleeve is rigidly connected to the axle mounting bracket and to the bracket of the brake assembly. The clamp of the brake assembly is preferably mounted on at least one wrapping band. Preferably, the mounting portion of the brake actuator includes a front plate that extends transversely from one of the side plates and the S-cam bearing assembly is mounted on the side plate near the other end of the side plate. Typically, the brake actuator is mounted near a first end of the bracket of the brake assembly, and the S-cam bearing is mounted near its second end. In one embodiment, at least one wrapping band has multiple ears, each ear having an opening, and the arcuate plate has corresponding openings formed along the inner edge. Fasteners, for example bolts, pass through the ear openings and the inner edge openings to mount the bracket of the brake assembly on the wrapping band. In one embodiment, the mounting portion of the brake actuator extends laterally from one end of the coupling portion and the S-cam bearing portion is substantially co-flattened with the coupling portion. In one embodiment, the arms are generally mounted on the shaft and the clamps of the brake assembly are generally mounted below the shaft. In another embodiment, the arms are generally mounted below the shaft and the clamps of the brake assembly are generally mounted below the shaft. The rear arm suspension according to the invention effectively controls or alleviates vertical bending moments, induced by rolling, and eliminates areas of concentration of stresses on the shaft that are susceptible to the initiation of cracks in response to the vertical bending moments induced by rolling. Additionally, it also provides a removable assembly of the brake actuator and components of the S-cam brake assembly in the axle mounting assemblies and thus prevents separate mounting of these components directly to the axle or beam of the rear arm. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in detail with reference to the accompanying drawings, in which: Figure 1 is a side elevational view of a suspension system according to a first embodiment of the invention, illustrating the mounting of a brake actuator in the axle assembly assembly according to the invention; Figure 2 is a perspective view of the axle assembly assembly and the bracket of the brake actuator illustrated in Figure 1; Figure 3 is a perspective view similar to Figure 2 and including components of the brake assembly; Figure 4 is a side elevational view of a second embodiment of a suspension system according to the invention, comprising an over-running suspension with a resilient shaft-to-beam connection and an S-cam brake assembly; mounted on the resilient shaft-to-beam connection by means of a brake actuator mounting bracket; Figure 5 is an enlarged, perspective, bottom view of a portion of the second suspension embodiment illustrated in Figure 4, as seen from the exterior of the vehicle; Figure 6 is an enlarged, perspective, bottom view of a portion of the second suspension embodiment illustrated in Figure 4, as viewed from the interior of the vehicle; Figure 7 is a perspective view of the mounting bracket of the brake assembly and the wrapping bands of the suspension system illustrated in Figure 4; Fig. 8 is a left rear perspective view of a third embodiment of a suspension system according to the invention, comprising an over-running suspension with a resilient shaft-to-beam connection and a brake assembly. S-cam mounted on a mounting bracket of the brake assembly; Figure 9 is a bottom left perspective view of the suspension of Figure 8; Figure 10 is a partial sectional view taken along line 10-10 of Figure 8; Figure 11 is a left bottom plan view of a fourth embodiment of a suspension system according to the invention, comprising a sub-chuck suspension with a resilient shaft-to-beam connection and a brake assembly. S-cam mounted on a brake actuator mounting bracket; and Figure 12 is a partial sectional view taken along line 12-12 of Figure 11. Description of the Preferred Embodiment Form Figures 1-3 illustrate a rear arm suspension 14 comprising an arm assembly rear 16 mounted on the frame 10 of the vehicle and carrying a shaft 12, holding wheels that make contact with earth (not shown) in a traditional manner. There are two rear arm assemblies, each mounted on opposite sides of the vehicle frame. For convenience, only one of the rear arm assemblies 16 will be described, it being understood that the description applies to both. The front of the vehicle is to the left of the frame, as seen in figure 1. The rear arm assembly 16 includes a rear arm 18 pivotally mounted in a hanging bracket 20 depending on the frame 10. The hanging bracket 20 has a pivot pin 22, preferably in the form of a bushing connector, at its lower end, for pivotally supporting the forward end of the rear arm 18. The rear arm 18 is preferably a rigid beam comprising a hollow rectangular construction. The rear arm 18 extends rearwardly along the frame of the vehicle 10. The rear end of the rear arm 18 is secured to an air spring 24, the upper end of which is fixedly mounted on the frame 10 of the vehicle. The rear arm 18 is known as an "over-pulled" rear arm as the shaft 12 is carried under the rear arm 18. To accommodate the shaft 12, the over-pulled arm has a slight downward bend between its front and rear ends. A connector with a front bushing 26 and a connector with a rear bushing 28 extend through the rear arm 18 near the slight fold down therein to hold an axle assembly assembly 30 while allowing limited articulation between the axle assembly assembly 30 and the rear arm 18. The upper portion of the air spring 24 is fixedly secured to the frame 10 of the vehicle. The shaft assembly assembly 30 comprises a pair of mounting plates 32, each having openings 34 to receive a portion of the bushing connectors 26, 28 to securely or resiliently attach the mounting plates to the arm 18. A S-cam mounting or bearing seat 36 is integrally formed with at least one of the mounting plates 32. The axle mounting assembly further comprises a pair of wrapping bands 40, each mounted on one of the mounting plates 32. Each of the wrapping bands 40 comprises a top plate in the form of U 42 fixedly connected to the mounting plate 32, preferably by welding at 44, and a U-shaped bottom plate 46. The welds 44 appear on both sides of the mounting plates. The U-shaped upper plate 42 extends laterally from each side of the mounting plate 32 to provide a semi-circular surface 45 to bear against the outer surface of the round shaft 12. The lower U-shaped plate also has a surface semicircular 47 supporting against the shaft 12. The upper and lower U-shaped plates are welded together at their corresponding ends 48, 50, respectively, by means of welds 52. The U-shaped upper plate 42 has a beveled relief area 52 near each longitudinal edge, which provides a slight relief to the axis at the side edges of the U-shaped upper plate 42. Similarly, the U-shaped lower plate 46 has a beveled relief area 54 at its side edges . The beveled relief areas 52, 54 effectively circumscribe the axis 12. These beveled areas prevent tension lifters on the shaft 12 that may result from the side edges of the U-shaped plates 42, 46 during vertical bending of the shaft. Bevelled areas are desirable in some cases, but they are not essential. The upper and lower U-shaped plates 42, 46, respectively, are mounted on the shaft and their corresponding ends 48, 50 clamped so that the U-shaped plates apply a compressive force to the shaft 12 to hold it in place without directly welding the plates 42, 46 to the shaft 12. Preferably, the plates 42, 46 are tensioned so as to apply compressive force to the shaft 12. The tension method is known and described in greater detail in the US patent application No. 09 / 134,856, which is incorporated by reference. With this configuration, the wrapping band compresses the shaft and distributes the compressive forces substantially uniformly around the shaft. The compressive force is sufficient to prevent the wrapping band from sliding on the shaft. A brake actuator clamp 70 is mounted on each of the U-shaped bottom plates 46. The brake actuator clamp 70 comprises a pair of triangular side plates 72 and a rectangular end plate 74. A central opening 76 and a pair of bolt openings 78 are formed in the rectangular end plate 74. A brake actuator chamber 80 is mounted in the brake actuator chamber bracket 70 by bolts (not shown) extending through the openings of bolt 78 in the rectangular end plate 74. An actuator rod 82 extends from the brake actuator chamber and is connected to an anvil 84 which in turn mounts a clearance adjuster 86. A cam arrow at S 90 is Rigidly connected to and rotatably driven by the slack adjuster 86. The S-cam arrow mounts an S-92 cam and is slewed in a S-bearing 94. The S-cam bearing 94 is mounted in the S-mount. c S-cam bearing S by bolts 96 extending through bolt openings 98 in the mounting plate 32. The brake assembly comprising the brake chamber 80, the actuator rod 82, the anvil 84, the adjuster clearance 86, the cam arrow at S 90, the cam at S 92, and the cam bearing at S 94 is entirely conventional and operates a brake on a wheel in a conventional manner. In operation, the vertical movement of the wheels that make contact with earth 14 is transferred by an axle 12 to the axle assembly assembly 30. The vertical movement of the axle assembly assembly 30 is translated to the rear arm 18 by the connector with front bushing 26 and the connector with rear bushing 28. The allowed joint between the axle assembly 30 and the rear arm 18 by 1 bushing of the front bushing connector 26 and the rear bushing connector 28 cushions the vertical movement of the rear arm 18 and relieves or attenuates the magnitude of the bearing-induced lifting moments transferred to shaft 12 from arm 18. Significant vertical displacement of shaft assembly assembly 30 causes vertical movement of rear arm 18. Vertical movement of rear arm 18 is allowed by the pivotal connection of the forward end of the rear arm 18 on the pivot pin 22. The vertical movement that of the rear arm 18 is cushioned and restricted by the air spring 24 and an impact absorber 60. Figures 4-7 illustrate a second embodiment of the invention where the entire brake assembly is mounted in the assembly of by means of a bracket assembly mounting bracket, instead of an actuator bracket and the axle mounting plates as in the first embodiment. As the first and second embodiments share many similar components, like reference numbers have been used to designate like parts. The shaft mounting assembly 130 of the second embodiment comprises a pair of clamp or mounting plates 132 mounted on the rear arm by the connectors with bushings 26 and 28. A U-shaped wrapping plate, upper 142 is integral with the mounting plate 132. As best seen in FIG. 7, the U-shaped upper plate 142 extends laterally from each side of the mounting plate 132 to provide a semi-circular surface 145 for supporting against the outer surface of the round shaft 12. A lower U-shaped plate 146 having upper edges 50 has a semi-cylindrical internal surface 154 that abuts against the external surface of the shaft 12. The upper and lower U-shaped plates 142 and 146 are joined by a weld 150 after being pressed together to apply compression to the shaft 12. The U-shaped bottom plates 146 have a pair of lugs 147, each with a hole therethrough 149. The shaft 12 mounts a spindle 100 which in turn assembles a brake mounting plate 102 in a conventional manner. A brake assembly mounting clamp 170 is mounted on each of the U-shaped bottom plates 146. The brake assembly assembly clamp 170 comprises a side plate 171, a front plate 174, and a side flange 172. The faceplate 174 has a central hole 176 and four mounting holes 178 arranged in a square pattern around the central hole 176. The side plate 171 has a pair of openings (not shown) through which the bolts 179 extend. The bolts 179 extend through the openings 149 in the ears 147 to mount the side plate 171 in one of the U-shaped bottom plates 146. The side flange 172 has an upper portion of an opening (not shown) through from which extends a bolt 179 that also extends through an opening 149 in an ear 147 on the U-shaped bottom plate 146 for mounting mounting bracket 170 thereon. Side plate 171 has a another an opening 197 and four mounting holes 198 spaced around the opening 197. A bearing bracket 200 formed of a plate 202 having four mounting holes 204, a bearing 206 with a central opening 208 and an arcuate slot 210 is mounted in the side plate 171 by 179 bolts that extend through the mounting holes 204 and corresponding holes in the mounting holes in the side plate 171 in a conventional manner. The bearing 206 projects through the opening 197 in the side plate 171. A brake actuator chamber 80 is mounted in the brake actuator chamber clamp 170 by bolts (not shown) extending through the openings of bolt 178 in the rectangular front plate 174 in a conventional manner. An actuator rod 82 extends from the brake actuator chamber and is connected to a clearance adjuster 84 by an anvil assembly 85. A S-cam arrow 90 is rigidly connected to and rotatably driven by the slack adjuster 84. The cam arrow at S 90 mounts an S-cam 92 and is muffled in the cam bearing assembly at S 200 comprising a plate 202, which is connected to the mounting plate 102 in a conventional manner. The S-cam bearing plate 202 is mounted to the bearing bracket 200 by bolts 212 which extend through the bolt openings 204 in the bearing mounting plate 200 and through corresponding bolt openings in the side plate. 171. A S-shaped cam bearing 206 is enmuñonado in the cam bearing plate in S 202. The S-cam arrow extends through the central opening 208 in the bearing bracket 200 and the cam bearing in S 206. The arcuate slot 210 provides an initial adjustment of the slack adjuster 84 relative to the cam arrow at S 90. The mounting holes 204 is in register with holes 198 in the side plate 171. An adjusting plate 214 is mounted non-rotatably in the slack adjuster 84 and has a flange 216 extending laterally and then upwardly. The upper portion of the flange 216 has an elongated slot 218 which is connected by a pin (not shown) to the arcuate slot 210 in a conventional manner to initially fix the position of the arrow of the slack adjuster with respect to the cam arrow in S 90 and to automatically adjust the clearance in the connection between the S-cam and the actuator shaft 82 in a conventional manner. The link of the brake actuator and the S-cam is conventional and does not form part of this invention, except insofar as it is mounted on the mounting bracket of the brake actuator. The brake actuator comprising the brake chamber 80, the actuator rod 82, the anvil assembly 85, the slack adjuster 84, the S-cam arrow 90 and the S-cam 92 are all conventional and operate on a brake on a wheel in a conventional manner. However, the mounting of the S-cam bearing and the brake chamber 80 in the axle mounting assembly prevents the welding of clamps to mount these components on an axle. Additionally it pre-places the S-cam portion of the brake assembly with the brake actuator, ensuring its relative continuous alignment, especially since both are connected to the same clamp, which is only connected to the axle assembly assembly. As illustrated in Figure 7, the mounting plate 132 assembles a U-shaped clamp 220 with holes 222 through welds 224. The impact damper 60 is pivotally mounted to one of the mounting plates 132 by a pin ( not shown), as is conventional in the field of suspension systems. Figures 8-10 illustrate a third embodiment of the rear arm suspension according to the invention, where like numbers have been used to designate equal parts. The third embodiment of the suspension is a sub-bracket suspension, comprising a rear arm or rigid beam 18 having one end pivotally mounted in a hanging bracket 20 by a connector with bushing 22. The hanging bracket depends on a frame of vehicle (not shown) in a well-known manner. An air spring 24 is positioned between a portion of the beam 18 and the frame rail. The air spring 24 dampens the pivotal movement of the rear arm 18 relative to the hanging bracket.
An axle mounting assembly 130 resiliently assembles an axle 12 on the beam 18. The axle assembly assembly comprises a pair of mounting plates 132, which are resiliently connected to the rigid beam 18 by a pair of connectors with bushing 26, 28. The mounting plates 132 includes a compression assembly comprising a first U-shaped wrapping plate 142, integrated with the mounting plates 132, and a second U-shaped wrapping plate 146, complementary , which is welded to the first U-shaped wrapping plate 142. The shaft 12 is compressively held between the first and second U-shaped wrapping plates 142 and 146 to securely mount the shaft to the assembly assembly shaft 130. As illustrated in Fig. 12, bushing connectors 26 and 28 are well known and comprise an outer sleeve 326 and an inner sleeve 328, between which an elastomeric ring 340 is disposed. External sleeve 326 is liger shorter than the inner sleeve 328. The outer sleeve 326 is rigidly welded between the sides of the rigid beam 18, whose length is smaller than that of the inner sleeve 328 so that relative movement between the beam 18 and the assembly can occur. Shaft Assembly 130. Sheaves 344 are positioned between the outer ends of the inner sleeve 328 and the mounting plates 132. The compression bolt 342 extends through the interior of the inner sleeve 328 and receives a nut 346, which upon tightening the nut 346, pin 342 compressively grasps mounting plates 132 to inner sleeve 328. The rear arm suspension further comprises a brake assembly mounting bracket 370 that mounts a brake actuator assembly to mounting plates 132. The brake actuator assembly is well known and generally comprises an air operated actuator 80 from which an actuator rod 82 extends, which reciprocates with relation to the actuator 80 upon the introduction and discharge of pressurized air into the brake actuator 80. A S-cam bearing 206 mounts a cam arrow 90 through a slack adjuster 86 and has an S-cam 92 at an external end of it. The rotation of the cam arrow 90 rotates the cam at S 92 to drive the brakes 344, which are mounted on the shaft 12. The mounting bracket of the brake assembly 370 comprises a mounting plate 371 which follows the rigid beam in parallel 18 and ends at one end on a brake actuator mounting platform 374 and at another end at a bearing retainer 383. The brake actuator platform 374 comprises mounting bolt openings and a push rod opening that receives bolts. 375 and an actuator rod 82 associated with the brake actuator 80. Nuts 377 are threaded in the bolts 375 to hold the brake actuator 80 to the brake actuator platform 374. The actuator rod 82 extends through the opening of push rod 376 when the brake actuator 80 is properly mounted to the longitudinal mounting plate 371. The bearing retainer 383 comprises an opening in which the cam bearing is received in S 2 06 and the cam bearing on S 206 is then fixed to the bearing retainer 383. Referring to Figs. 9 and 10, the brake assembly mounting clamp 370 is rigidly connected to the axle mounting plates 132 by passing the bolts. assembly connector 342 through bushings in the longitudinal mounting plate 371. Cylindrical spacers 381 are positioned between the outside of one of the mounting plates 132 and the longitudinal mounting plate 371 and slidably receive the bolts. assembly 342. When tightening the nuts 346, the longitudinal mounting plate 371 is brought compressively against the spacers 381, which are brought against the outside of the mounting plates 132. Similarly, the mounting plates 132 are brought compressively against the rollers 344 and the inner sleeve 328 of the bushing connectors 26, 28 to grip the mounting bracket of the brake assembly 370 to the mounting plates 132. A benefit of the Third embodiment of the invention is that the longitudinal bending forces acting on the shaft are effectively absorbed by the resilient shaft-to-beam connection between the shaft assembly assembly 130 and the rigid rear arm 18. That is, in other words, as the inner sleeve 328 of the socket connector 26, 28 rigidly connects the shaft mounting assembly 130 and the mounting bracket of the brake assembly 370, and the outer sleeve 326 of the socket connector 26, 28 is connected rigidly to the rigid rear arm 18, the inherent resilient movement of the inner sleeve 328 relative to the outer sleeve 326 of the socket connector, allowed by the compression of the elastomeric ring 340 disposed between the inner sleeve 328 and the outer sleeve 326, resiliently connects the axle mounting plates 132, the axle tube 12, and the mounting bracket of the brake assembly 370 to the rigid beam 18 This resilient shaft-to-beam connection allows the torsional forces applied to the rear arm to be substantially absorbed by the bushing connectors 26, 28 before the torsional forces are applied to the shaft 12. Another advantage of the invention is that the brake actuator 80 and the S-cam bearing 206 are conveniently mounted to the shaft mounting assembly 130 by the mounting bracket of the brake assembly 370 instead of mounting the brake actuator 80 and the bearing cam on s 206 on shaft 12. In previous rear arm suspensions, it was common to rigidly mount the brake actuator 80 and the cam bearing on S 206 directly on shaft 12, thus for a proper In the case of brake operation, it is necessary that the brake actuator 80 and the cam bearing in S 206 remain aligned with the brake 344, which is mounted directly on the shaft. Unfortunately, the direct mounting of the brake actuator 80 and the cam bearing on S 206 on the shaft 12 previously required the welding of clamps directly to the shaft, which can cause stress risers induced by torsional force on the shaft. The present invention addresses the difficulties and disadvantages of mounting the brake actuator 80 and the cam bearing at S 206 directly on the shaft by rigidly mounting the brake actuator 80 and the cam bearing at S 206 directly to the mounting assembly of the brake assembly. shaft 130 by the mounting bracket of the brake assembly 370, effectively creating a rigid unitary structure from the axle assembly assembly 130, the brake assembly assembly bracket 370, the brake actuator 80, and the bearing of cam on S 206. Figures 11 and 12 illustrate a fourth embodiment of rear arm suspension according to the invention. The fourth embodiment of the rear arm suspension is substantially identical to the third embodiment, except for the mounting bracket of the brake assembly 470. Thus, equal parts in the fourth embodiment will be identified by equal numbers and only The mounting bracket of the brake assembly 470 of the fourth embodiment will be described in detail.
The mounting bracket of the brake assembly 470 comprises a laterally extending actuator platform 474 comprising the spaced arms 471, 473, which are connected at an apex 475. Mounting bolt openings 478, together with a rod opening push 476, are formed in the arm 473. Similarly, a push rod opening 477 is formed in the arm 471. The actuator 80 is mounted to the arm 473 by inserting the actuator mounting bolts 375 and an actuator rod 82. through the mounting bolt openings 478, and the push rod openings 476, 477, respectively. The nuts 377 are then threaded into the brake actuator mounting bolts for compressively retaining the actuator in the arm 473. The mounting bracket of the brake assembly 470 further comprises mounting flanges 479, 481 which, respectively, extend away from the arms 471, 473. Each of the mounting flanges 479, 481 includes openings through which the connector mounting bolts with bushing 342 are received and threaded with nuts 346 to compressively retain the hose clamp. assembly of the brake assembly 470 on the axle mounting plates 132. The mounting bracket of the brake assembly 470 further includes a bearing assembly 483 having a generally L-shaped cross section and extending outwards and upwards of the mounting tab 479. The bearing assembly 483 receives and assembles the cam bearing on S 206. The fourth embodiment of the rear arm suspension s ub-tie that has a rigid beam with a resilient shaft-to-beam connection with a brake assembly mounting clamp 470 rigidly connected to the shaft mounting plates 132 provides the same advantages as the second embodiment. Namely, the shaft 12 is compressively held by the shaft assembly assembly 130, the shaft assembly assembly 130 is resiliently mounted on the rigid beam and allows relative movement between the beam and the shaft, and the bearing S-cam and brake actuator are rigidly connected to the shaft clamp. The above description of a rear arm suspension is for purposes of illustration and is not intended to be a limitation of the types of suspensions in which the axle mounting assembly according to the invention can be used. For example, the axle assembly assembly according to the invention can be used on all different types of rear arm suspensions, leaf spring suspensions, and combinations of the two types. In addition, the suspensions using the axle assembly assembly according to the invention can be used in trucks, trailers, trucks and other types of heavy-duty vehicles, including cross-country vehicles as well as land vehicles.
Variations and reasonable modifications are possible within the scope of the above disclosure and drawings, without departing from the spirit of the invention, which is defined in the appended claims.