MXPA97008816A - Rear arm suspension with envolt compression axle assembly - Google Patents

Abstract

A vehicle suspension system for mounting wheels that link to the ground in a vehicle frame (10), where two arms (18) are secured to opposite sides of the frame and a wheel carrying axle (12) is suspended between the arms the shaft is secured to the arms by a wrapping plate (34) partially surrounding the shaft, adapter plates (39) mounted on the inner surface of the wrapping plate and at least one pin (38) for compressing the wrapping plate around of the shaft and the adapter plate against the shaft. In this configuration, the wrapping plate supports and strengthens the shaft. The wrapping plate generally conforms to the profile of that portion of the surrounding shaft. The axis can be square, oval, hexagonal, octagonal, rectangular or D-shaped in cross section. The wrapping plate and the adapter plates exert substantially transverse forces on the shaft. An opening (42) is formed in the wrapping plate on its side at a location corresponding to the vertical midpoint of the adjacent side of the shaft. A circular sheave (44) is welded to the shaft on each side thereof in register with the openings in the side of the wrapping plate to prevent lateral translation of the wrapping plate with respect to the

Description

SUSPENSION OF REAR ARM WITH MOUNTING PRINTING OF WRAPPING BACKGROUND OF THE INVENTION Casapoys? Axi? Co This invention relates to vehicle suspension systems for mounting wheels that link the ground to a vehicle frame, and more particularly to a rear arm suspension axle in which a carrier axle of wheels is secured to a rear arm. In one of its aspects, the invention relates to a method of mounting an axle support assembly on an axle for the wheels that link to the ground. Description of the Related Art In U.S. Patent No. 4,693,486, issued to Pierce et al. (Issued September 15, 1987), a rear arm suspension has a shaft secured to a rear arm by a wrapping plate that it partially surrounds the shaft, a pin being used to compress the wrapping plate around the shaft so that the wrapping plate supports and strengthens the shaft, and a circular plug weld joins the wrapping plate to the shaft. U.S. 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 suspension structure of the vehicle. The welding that secures the shaft to the clamp is usually done at the midpoint of the shaft side where the vertical bending moment stresses are neutral. The shafts are typically welded to the clamps in order to attach the shaft to the clamp under high load conditions. The shaft is welded to the shaft clamp by a line weld on either side of the clamp. Because "it is a line weld, the weld has" ends "in which stresses are concentrated and in which cracks can be initiated. U.S. Patent No. 5,116,075, issued to Pierce, discloses a rear arm suspension with a wrap compression shaft assembly similar to that of the 4,693,486 patent of Pierce et al., Except that the opening in the wrapping plate is Removed and blocks are welded to the shaft adjacent to the wrapping plate to prevent lateral translation of the wrapping plate with respect to the shaft. Although this arrangement is relatively satisfactory, it has been found that the blocks can give rise to stress cracks at the points where the blocks are welded to the shaft. It has been found that the highest stress points in this suspension are at the edges of the wrapping plate, where the blocks are placed and that these stresses cause the greatest stresses on the shaft at that point. It has additionally been found that at the axial midpoint of the envelope at the vertical center of the shaft, minimal stresses appear on the shaft. SUMMARY OF THE INVENTION The invention relates to vehicle suspension systems for mounting the wheels «which link the ground to a vehicle frame and to a method for mounting an axle support assembly to an axle. The suspension system comprises at least two substantially rigid arms secured to opposite sides of the frame. The arms are secured to the vehicle frame through substantially aligned pivot assemblies. At least one wheel bearing axle is mounted on the arms. A wrapping plate having a complementary, flattened, elongated surface wraps around the axis at least 180 °. Opposite sides of the wrapping plate extend beyond the lower portion of the shaft. At least one bolt extends through the wrapping plate on its opposite opposing sides to diametrically compress opposite sides of the shaft. In accordance with the invention, the wrapping plate has at least one opening positioned on one side of the wrapping plate in a position around the vertical midpoint of the shaft. A sheave is welded to the shaft and is in register with the opening of the wrapping plate to prevent lateral displacement of the wrapping plate with respect to the shaft. Preferably, the sheave is of annular shape and is welded to the shaft through welds to a central opening in the sheave. In a preferred embodiment, the opening of the wrapping plate is in an axial central portion of the wrapping plate. 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 fragmentary view, in side elevation, of a vehicle frame having mounted on it a suspension system of according to the invention; Figure 2 is a fragmentary, side, sectional, amplified view of the suspension shown in Figure 1; Figure 3 is a sectional view taken along line 3-3 of Figure 2; and Figure 4 is a sectional view taken along line 4-4 of Figure 3. Description of the Preferred Embodiment With reference to the drawings, and to Figure 1 in particular, a vehicle frame 10 has an axle 12 and wheels that link to the ground 14 (shown in phantom lines) suspended therefrom by a suspension system 16 according to the invention. The front of the vehicle is to the left of the frame, as seen in figure 1. The suspension system 16 includes, on each side of the frame of the vehicle 10, a rear arm 18 pivotally mounted to a hanging bracket 20 that depends on the frame 10. The hanging bracket 20 has a pivot pin 22 at its lower end for pivotally supporting the forward end of the rear arm 18. The rear arm 18 comprises a hollow rectangular member for supporting the shaft 12. The forward end of the rear arm 18 is pivotally mounted on the pivot pin 22. The rear arm 18 extends rearward along the frame of the vehicle 10. The rear end of the rear arm 18 is secured to an air spring 24. The rear arm 18 has a fold toward down, light, intermediate between its front and rear ends. A front sleeve pin 26 and a rear sleeve pin 28 extend through the rear arm 18 near the slight fold down therein to support an axle support assembly 30 while allowing limited articulation between the axle support assembly 30. and the rear arm 18. The upper portion of the air spring 24 is fixedly secured to the frame of the vehicle 10. In operation, the vertical movement of the wheels "which engage the earth 14 is translated through the shaft 12 to the support assembly. of axle 30. The vertical movement of the axle support assembly 30 is translated to the rear arm 18 through a front sleeve pin 26 and the rear sleeve pin 28. With reference to figure 3, a sleeve 29 accommodates the pins sleeve 26, 28. The limited articulation allowed between the axle support assembly 30 and the rear arm 18 by the sleeve 29 of the front sleeve pin 26 and the past or rear sleeve 28 cushions the vertical movement of the rear arm 18 and against the bearing rate of the suspension allowing the axle support assembly 30 to make small vertical and conical displacements relative to the rear arm 18. The significant vertical displacement of the assembly Shaft support 30 causes vertical movement of the rear arm 18. Vertical movement of the rear arm 18 is permitted by the pivotal connection of the forward end of the rear arm 18 to the pivot pin 22. The vertical movement of the rear arm 18 is cushioned and restricted by the air spring 24 and a shock absorber (not shown). The support assembly of ej'e 30 comprises a pair of side plates 32 arranged on each side of the rear arm 18, a U-shaped wrapping plate 34 depending on the side plates 32, a reinforcing plate 36, a bolt 38 and adapter plates 39. The bolt 38 passes through the end of the U-shaped wrapping plate 34 for compressing the sides of the wrapping plate 34. Each side plate 32 comprises a vertical plate having openings in its upper portion for receiving the front sleeve pin 26 and the rear sleeve pin 28. The front sleeve pin 26 and the rear sleeve pin 28 extend through the rear arm 18 and through corresponding openings in the pair of side plates 32 disposed on each side of the rear arm 18 to secure the side plates 32 to the rear arm 18, thereby supporting the assembly of the axle support 30 while limited articulation is allowed between the side plates 32 and the rear arm 18. Furthermore, each side plate 32 has a U-shaped opening adapted in its po lower portion to receive in a complementary manner the eyelet portion of the U-shaped wrapping plate 34. The side plate 32 thereby acts to provide a surface to which the wrapping plate 34 can be secured and by means of welding and it also acts to reinforce the wrapping plate 34. The wrapping plate 34, as seen in Figure 3, is a saddle-shaped plate. As seen in Figure 2, the wrapping plate 34 is of a U-shaped cross section. The eye portion of the wrapping plate 34 is disposed upwardly within the side plates 32 and the open end of the plate. of wrapping 34 extends downwards. The wrapping plate 34 is secured to the side plates 32 by suitable means such as welding. The wrapping plate 34 is configured to loosely receive the shaft 12 having a square, rectangular or other non-circular cross-sectional configuration with a small space between the upper surface of the shaft and the inner surface of the wrapping plate 34. As can be seen in Figure 3, the wrapping plate 34 has an opening 34 in the eyelet portion of the U-shaped wrapping plate 34 to reduce the overall weight of the shaft support assembly 30, to increase the flexibility of the wrapping plate 34 and provide free space for the rear arm. The wrapping plate 34 includes bolts 38 which extend through the sides of the U-shaped wrapping plate 34. When assembled, the bolts 38 are positioned below the shaft 12 and are adapted to position the side of the plate. U-shaped wrapping 34 in compression against the shaft 12 when the bolts 38 are tightened. Adapter plates 39 are incorporated to improve the gripping effect of the wrapping plate 34 on the shaft 12. The adapter plates 39 are fixedly attached to the inner surface of the wrapping plate 34 at a point just below the opening in the wrapping plate 34 for the bolts 38. The adapter plates 39 are U-shaped in cross section, with two upstanding leg portions 31 and an eyelet portion 33. The adapter plates 39 are assembled such that the upper surface of the two portions of erect leg 31 make contact with the lower surface of the shaft 12. The shaft support assembly 30 also includes a reinforcing plate 36 secured as by means of welding to the side plate 32 and the wrapping plate 34 to support and reinforce the wrapping plate 34. A shock-absorbing clamp 37 is provided on the inner side plate 32 to secure a lower portion of a shock absorber (not shown) for shock absorber. The axle support assembly 30 is described in the preferred embodiment as a plurality of plates fixedly joined to each other by suitable means such as welding, it can also easily be underd that a single assembly can be formed. shaft support by a forge. According to the invention, the wrapping plate includes at least one and preferably two openings 42 on its sides at a position approximately at the vertical midpoint of the shaft 12. An annular sheave 44 is welded to the shaft at a vertical midpoint of the shaft 12 and in register with the opening 42. The sheave 44 has a central opening 46. Preferably, the sheave 44 is welded to the shaft in the opening 46 through welds 48. The outer diameter of the sheave 44 closely resembles the inside diameter of the opening 42 and extends toward the opening to prevent relative lateral displacement between the wrapping plate 34 and the shaft 12. Welding the pulley 44 to the shaft 12 at the midpoint of the shaft and centrally with respect to the wrapping plate 34 minimizes the forces between the wrapping plate and the shaft 12 to prevent displacement of the wrapping plate 34 with respect to the shaft 12. If desired, the openings 42 in the wrapping plate 34 may be displaced axially. Each other and the sheaves 44 can similarly be welded to the shaft in places axially offset from each other. In operation, the shaft 12 is secured within the wrapping plate 34 by first inserting the shaft 12 into the complementary wrapping plate, U-shaped 34 and then gripping the shaft 12 forcefully towards the wrapping plate 34. The bolt 38 it is tightened until the wrapping plate 34 is loose against the shaft 12. Then, the adapter plates 39 are fixedly joined as by welding to the inner surface of the wrapping plate 34 such that the erect leg portions 31 contact the bottom surface of the shaft 12. With the adapter plates 39 secured in place, the bolt 38 is further tightened to create compression forces on the shaft 12. When the bolt 38 is tightened, as shown in Fig. 2, the sides of the bolts 38 wrapping plates exert a first diametrical compression force on the complementary sides of the shaft 12 in the direction of the arrow Fl. The tightening of the bolt 38 also causes the dependent ends of the U-shaped wrapping plate 34 to bend or flex inwardly. This inward bend results in a slight rotation of the lower part of the wrapping plate around the lower corners of the shaft 12 to introduce a horizontal component of movement toward the lower end of the wrapping plate 34. This inward fold of the wrapping plate 34 at its ends results in the application of a vertical force component F2, on the shaft 12, by the adapter plates 39. In this way, the horizontal force on the ends of the wrapping plate in U-shape 34 is translated to a second compression force F2, which is transverse to the first force Fl. The transverse compression force F2 exerted by the adapter plates 39 on the shaft together with the compression force Fl exerted throughout of the internal faces of the wrapping plate 34 provides sufficient gripping resistance for the shaft support assembly 30 on the shaft 12, and strengthens the shaft against the torsional efforts and bending efforts. As illustrated in Figure 3, the sheave 44 is aligned with the opening 42 in the wrapping plate 34. Preferably, the wrapping plate 34 contains two openings, one on each side of the shaft, and further comprises two sheaves 44, each in register with an opening. The rollers 44 are positioned in the openings 42 and are welded in place by plug welds 48 between the pulley and the shaft 12. As illustrated in Fig. 3, the welds 48 are preferably placed in the central opening 46 of the sheave 44. The weld of the sheave 44 on the shaft 12 must take place after the U-shaped wrapping plate 34 is completely attached to the shaft 12. Other shaft shapes can be used, such as D-shape, hexagonal , octagonal and rectangular, according to the invention, simply by modifying the configuration of the wrapping plate to conform to the cross section of the shaft. The invention overcomes the problem of potential stress fractures at the ends of the wrapping plate and provides a simple and hurried method of assembling a suspension system according to the invention, with a minimum of effort. The suspension system is more effective than the suspension systems of the prior art. Reasonable variations and modifications are possible within the scope of the foregoing disclosure, without departing from the spirit of the invention, which is defined in the appended claims.

Claims (7)

1. CLAIMS 1. In a vehicle suspension for mounting wheels that link the ground to a vehicle frame, the suspension system comprises at least two substantially rigid arms secured to opposite sides of the frame through substantially aligned pivot mounts; at least one wheel carrying axle mounted on said arms through a wrapping plate having a complementary, flattened, elongated surface that wraps at least 180 ° about said axis and dependent opposite sides extending beyond said axis; and at least one bolt for diametrically compressing said shaft by stretching said opposite sides of said wrapping plate toward one another; the improvement comprising: an opening on at least one side of the wrapping plate; a sheave in the opening and welded to the shaft; the lateral dimension of the sheave generally conforming to the lateral dimension of the opening to prevent lateral displacement of the opening plate with respect to the axis.
2. 2. A vehicle suspension system according to claim 2, wherein the opening in the wrapping plate is of circular configuration and the sheave is of circular configuration.
3. 3. A vehicle suspension system according to claim 2, wherein the sheave is of annular configuration and the sheave is welded to the shaft in a central opening in the sheave.
4. 4. A vehicle suspension system according to claim 1, wherein the opening is positioned in an axial central portion of the wrapping plate.
5. 5. In a method for mounting an axle support assembly on an axle for wheels that link to the earth, comprising the steps of: inserting an axle into a complementary, flattened, elongated surface of a wrapping plate having at least an opening; inserting a bolt through opposite sides of said wrapping plate; tightening said bolt until said wrapping plate contacts the opposite sides of the shaft; the improvement comprising: placing a sheave in at least one opening in the wrapping plate, and welding the sheave to the shaft.
6. A method for mounting an axle support assembly on an axle for wheels that link to the ground, according to claim 5, wherein the sheave has a cross dimension approximately equal to a cross dimension of the at least one opening for prevent lateral displacement of the wrapping plate with respect to the shaft.
7. 7. A method for mounting an axle support assembly on an axle for wheels that link to the ground, according to claim 6, wherein the sheave is of annular configuration and the welding step comprises placing a welding eyebrow in a central opening of the sheave. A vehicle suspension system for mounting wheels that link to the ground in a vehicle frame (10), where two arms (18) are secured to opposite sides of the frame and a wheel carrying axle (12) is suspended between the arms . The shaft is secured to the arms by a wrapping plate (34) partially surrounding the shaft, adapter plates (39) mounted on the inner surface of the wrapping plate and at least one pin (38) for compressing the wrapping plate around the shaft and the adapter plate against the shaft. In this configuration, the wrapping plate supports and strengthens the shaft. The wrapping plate generally conforms to the profile of that portion of the surrounding shaft. The axis can be square, oval, hexagonal, octagonal, rectangular or D-shaped in cross section. The wrapping plate and the adapter plates exert substantially transverse forces on the shaft. An opening (42) is formed in the wrapping plate on its side at a location corresponding to the vertical midpoint of the adjacent side of the shaft. A circular sheave (44) is welded to the shaft on each side thereof in register with the openings in the side of the wrapping plate to prevent lateral translation of the wrapping plate with respect to the shaft.