AU2016101677B4 - An independent suspension assembly for a trailer - Google Patents

Abstract

An independent suspension assembly for a vehicle, said suspension assembly comprising: a trailer mounting subassembly for attachment to a trailer; a suspension arm extending from the trailer mounting subassembly, said suspension arm being arranged to swing relative to the trailer mounting subsassembly; a stub axle extending laterally from the suspension arm; and a support subassembly fast with a remote end of the suspension arm, the support subassembly being adapted for supporting a resilient member; wherein a portion of the stub axle fast with both the support subassembly and said suspension arm.

Description

2016101677 19 Sep 2016 AUSTRALIA PATENTS ACT 1990

INNOVATION PATENT SPECIFICATION

AN INDEPENDENT SUSPENSION ASSEMBLY FOR A TRAILER

The following statement is a description of the invention: 2016101677 19 Sep 2016 1

AN INDEPENDENT SUSPENSION ASSEMBLY FOR A TRAILER

TECHNICAL FIELD

[01] The present invention is directed to an independent suspension assembly for a vehicle. The invention is particularly for a towed vehicle such as a trailer, for example a box trailer or a caravan.

BACKGROUND

[02] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.

[03] Suspension assemblies for vehicles must meet a number of conflicting requirements. On the one hand, the suspension assemblies must be sufficiently heavy duty and robust to endure prolonged driving over rough ground while providing a high degree of suspension and a quality ride. On the other hand, they must also not be so heavy that they unduly increase the weight of the vehicle. Furthermore, it is often desirable that space be available beneath a vehicle such as a caravan for water tanks and the like. Consequently, it is desirable that a suspension assembly also be as compact as possible.

[04] Independent suspension assemblies for vehicles such as box trailers and caravans have been known in the past. For example, Figure 1 depicts plan and side views of a trailer chassis fitted with independent suspension assemblies of a type that include a spring coil and a shock absorber. The independent suspension assembly that is illustrated has been used in the past with great success. Nevertheless, it would be desirable if an even more compact, lighter and readily manufactured product were available. 2 2016101677 07 Dec 2016 [05] It is an object of the invention to provide an independent suspension assembly that is an improvement, or at least a useful alternative, to those suspension assemblies that have hitherto been known in the prior art.

SUMMARY OF THE INVENTION

[06] According to a first embodiment of the present invention there is provided an independent suspension assembly for a trailer, said suspension comprising: a trailer mounting subassembly for attachment to the trailer; a tubular suspension arm extending from the trailer mounting subassembly, said tubular suspension arm being arranged to swing relative to the trailer mounting subassembly ; a stub axle extending laterally from the suspension arm; and a support subassembly fast with a remote end of the tubular suspension arm, the support subassembly adapted for supporting a resilient member; wherein a portion of the stub axle is fast with both the support subassembly and said tubular suspension arm.

[07] Preferably the stub axle is fast with a remote end of the tubular suspension arm, preferably at a location between a supporting portion of the support subassembly, the supporting portion being adapted for supporting the resilient member, and the trailer mounting subassembly.

[08] In a preferred embodiment of the invention the support subassembly supports a resilient member in the form of a coil spring. Other resilient members may also be used such as an air bladder, block of synthetic rubber or a leaf spring.

[09] A shock absorber may also be coupled to the support subassembly, either to supplement the resilient member or as an alternative thereto. 2016101677 19 Sep 2016 3 [10] The support subassembly may further include a formation for coupling a second shock absorber thereto.

[11] In a preferred embodiment of the invention, the supporting portion of the support subassembly includes a support member that spans the side plates.

[12] Preferably the resilient member is mounted above a portion of the support member and also above an edge of one of the side plates.

[13] In a preferred embodiment of the invention a remote end of the stub axle terminates in an integrally formed spindle. Alternatively, the spindle may be a separate item that is fastened to the stub axle in some other embodiments.

[14] In an embodiment, the invention further comprises a hinge assembly arranged to swing relative to the trailer mounting subassembly.

[15] Preferably, the suspension arm extends from the hinge assembly.

[16] Preferably, the hinge assembly comprises a hinge tube supported by a spindle extending therethrough.

[17] The trailer mounting subassembly preferably includes a pair of spaced hinge side plates. Preferably, the spindle supporting the hinge tube is supported by the side plates.

[18] In a preferred embodiment of the invention the hinge side plates rotatably support the spindle therebetween.

[19] In one embodiment of the invention a camber (or as it is sometimes called a “boe-in”) adjustment assembly is provided. For example, the camber adjustment assembly may include a cam fastened to an end of the spindle and arranged to abut a side wall of a hole formed through the corresponding hinge side plate. 4 2016101677 19 Sep 2016 [20] The cam preferably includes peripheral formations for engagement by a correspondingly formed adjustment tool.

[21] In a further embodiment of the invention the axis of the spindle is held fast relative to the trailer mounting subassembly.

[22] For example, the axis of the spindle may be held fast relative to the trailer mounting subassembly by corresponding spindle capture members on each end of the spindle which capture opposite ends of the spindle and which are fast with the trailer mounting assembly.

[23] In a preferred embodiment of the invention the hinge tube penetrates through the suspension arm. For example, the suspension arm is preferably formed to provide a passageway for the hinge tube to pass through.

[24] Preferably a stiffening member is connected between the hinge tube and the suspension arm to counteract sideways forces exerted on the suspension arm in use.

[25] In a preferred embodiment of the invention the hinge side plates are interconnected by a hinge bar for imparting rigidity to the trailer mounting subassembly.

[26] Preferably opposite ends of the hinge bar are received into complementary slots formed into upper ends of the side plates.

[27] According to a further aspect of the present invention there is provided an independent suspension assembly for a vehicle, said suspension comprising: a trailer mounting subassembly; a suspension arm extending from the trailer mounting subassembly and hingedly connected thereto; a support subassembly fast with an end of the suspension arm remote from the trailer mounting subassembly for supporting a resilient member; 2016101677 19 Sep 2016 5 a stub axle extending laterally from the suspension arm; wherein a portion of the stub axle extends through both the support subassembly and through said remote end of the suspension arm.

[28] According to another aspect of the invention there is provided a method for providing independent suspension to a vehicle including: fastening a hinge bar of the previously described independent suspension assembly to a chassis member of the vehicle; and fastening an upper end of a resilient member comprising a coil spring to the, or a further, chassis member of the vehicle wherein the coil spring is vertical during use of the vehicle upon a horizontal surface; and connecting at least one shock absorber between the support subassembly and the chassis of the vehicle.

[29] According to another aspect, the invention comprises a trailer including the independent suspension assembly described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[30] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: [31] Figure 1A is a top plan view of a prior art independent suspension assembly installed on a trailer chassis’ members.

[32] Figure 1B is a top plan view of the components of the prior art suspension assembly of Figure 1A laid out. 6 2016101677 19 Sep 2016 [33] Figure 2 depicts a side view of an installed independent suspension assembly according to a preferred embodiment of the present invention.

[34] Figure 3 depicts left and right hand side versions of the independent suspension assembly of Figure 2.

[35] Figure 4 is a further view of the independent suspension assembly of Figure 2.

[36] Figure 5 is a view of an independent suspension assembly according to a further embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[37] Referring now to Figure 2, there is shown a side view of an independent suspension assembly 1 according to a preferred embodiment of the present invention and mounted to chassis members 2 and 4 of a vehicle such as a trailer.

[38] Figure 3 is a non-plan view of the independent suspension assembly 1, which is for supporting a first wheel 5 and also its mirror image 3, which is for supporting a second wheel 7. Figure 4 is a further view of suspension assembly 1.

[39] The following description of the independent suspension assembly will be made with reference to independent suspension assembly 1, although it will be realised that it applies equally to suspension assembly 3.

[40] Referring again to Figure 4, the suspension assembly 1 comprises a trailer mounting subassembly 21 which comprises spaced hinge side plates 10a, 10b. A hinge bar 6 spans between and interconnects the hinge side plates in order to impart rigidity to the trailer mounting subassembly. Opposite ends of the hinge bar 6 are received into complementary slots formed into upper ends of the side plates and welded thereto. In use the hinge bar 6 is 2016101677 19 Sep 2016 7 welded or otherwise fastened to a member of a vehicle, such as the cross bar 4 (visible in Figure 2) of a trailer, to which the independent suspension assembly 1 is installed.

[41] The hinge side plates 10a, 10b support a rotatable hinge tube assembly 13 between them. In the presently described exemplary embodiment the rotatable hinge tube assembly 13 is comprised of a square cross section hinge tube 11. In other embodiments tubes of other suitable cross sectional shapes might be used for the hinge tube 11 and also for the other members that will be described.

[42] The hinge tube 11 is supported between the side plates 10a, 10b by an elongate member, in the form of a rod or “hinge spindle” 12 (shown in Figure 2 and also in Figure 5). The spindle 12 extends through the hinge tube 11.

[43] A suspension arm 16 extends from the hinge tube 11. The suspension arm 16 is formed with a passage at one end through which the hinge tube 11 snugly passes and about which it is welded to the suspension arm 16. A diagonal stiffening member 14, comprised of square section steel, is connected between the hinge tube and the suspension arm and acts to counteract sideways forces exerted on the suspension arm in use.

[44] A camber adjustment mechanism is provided at either end of the hinge spindle 12. The camber adjustment mechanism includes a cam 17, which is a disk mounted eccentrically to the end of the hinge spindle 12. The cam abuts an internal wall of a hole 19 formed through the corresponding hinge side wall 10a or 10b. Cam 17 is formed with peripheral formations, e.g. indentations and/or protrusions which complement a ring 25 (visible in Figure 3) in the head of an adjustment wrench 27. Accordingly by rotating the cam the angle of the hinge rod 11, and so also the suspension arm 16, can be adjusted relative to the side plates. Once in a desired position the bolt 29 is tightened on the end of the spindle 12, about which it is threaded, in order to retain the cam in the desired position. 8 2016101677 19 Sep 2016 [45] A support subassembly 31 is fastened at the end of the suspension arm 16 remote from the trailer mounting subassembly 21. The support subassembly 31 is provided to support a resilient member, which in the presently described exemplary embodiment comprises coil spring 28.

[46] Support subassembly 31 includes a pair of side plates 26a, 26b mounted on opposed sides of said remote end of the suspension arm 16. A square section stub axle 22 extends laterally from the end of the suspension arm 16. The stub axle 22 is formed of a solid bar of steel with an outer end machined to provide a wheel spindle 24. A brake mounting plate 18 is provided at the base of the spindle 24 for attachment of a wheel brake.

[47] The inner end of the stub axle extends through complementary passageways formed through side plate 26a, the remote end of suspension plate 16 and side plate 26b. The side plates, stub axle and suspension arm are all welded together. It will be realized that by providing a stub axle, which passes through complementary passageways formed in the side plates 26a and 26b, the single suspension arm is strongly and rigidly connected to both the support platform subassembly 31 and the stub axle 22.

[48] The support subassembly 31 includes a support member, which in the present embodiment comprises a support platform 33 that spans the side plates 26a and 26b and which provides a region for supporting the resilient member, e.g. coil spring 28.

[49] Coil spring 28 is mounted on the upper edge of side plate 26a and the support platform 33. The base of the coil spring 28 is further supported by means of a lateral strengthening rib 35 which is welded to, and outwardly extends from side plate 26a.

[50] In addition to coil spring 28 the support subassembly 31 also serves as a mounting point for a lower end of shock absorber 30. Shock absorber 30 is a bounce and rebound dampening shock absorber. It acts in conjunction with the spring 33 to provide suspension between the wheel mounted to spindle 24 and the vehicle to which the suspension assembly 1 is mounted. The shock 9 2016101677 19 Sep 2016 absorber 30 is mounted at its lower end to the support subassembly 31 by means of a bolt 37 and nut 32. At its upper end shock absorber 30 is fastened to bracket 38 which in turn is fast with plate 36. During installation of independent suspension assembly 1 the plate 36 is welded to a chassis member of the trailer.

[51] The upper end of coil spring 28 is welded to top plate 43 from which there extends upwardly a right angled attachment fin 45.

[52] A second shock absorber may also be coupled to the support subassembly 31, either to supplement the coil spring or as an alternative thereto. The second shock absorber may be mounted between mount holes 41 of plates 26a, 26b and mounting bracket 40 (shown in Figure 2) which is welded to a chassis member of the trailer.

USE FOR THE INVENTION

[53] In use the independent suspension assembly 1 is installed to the underside of the chassis of a vehicle, such as a trailer - for example a box trailer or caravan. This is done by welding the hinge bar 6 to a member of the vehicle chassis, such as cross bar 4 (shown in Figure 2). The coil spring top plate 43 and attachment fin 45 are similarly welded to side rail 2 (shown in Figure 2) of the vehicle chassis. The upper end of shock absorber 30 is made fast with second cross bar 34 of the vehicle by welding plate 36 thereto.

[54] A wheel with tyre is then attached to the spindle 24 of stub axle 22. Similarly, a corresponding mirror image independent suspension assembly 3 (shown in Figure 3) is attached to the opposite underside of the vehicle.

[55] Once the independent suspensions have been installed and fitted with wheels and tyres the vehicle, for example a box trailer, caravan or the like may be towed over rough ground. The suspension arm 16 swings about the hinge assembly 13 in response to undulations in the ground. However the forces due to the undulations are effectively absorbed by the resilient member 2016101677 19 Sep 2016 10 in the form of the coil spring 28. It will be realised that the coil spring 28 might be replaced by other types of resilient members in other embodiments. For example, air bladders, leaf springs or blocks of synthetic rubber might be used in some other embodiments.

[56] Furthermore, in the presently described preferred embodiment of the invention the shock absorber 30 acts to dampen the swinging of the suspension arm in both bounce and rebound.

[57] Variations of the invention are possible. For example, Figure 5 shows an independent suspension assembly 100 according to a further embodiment of the invention. In this embodiment the axis of the spindle 12 is held fast relative to side plates 10a, 10b of the trailer mounting subassembly 21 by corresponding spindle capture members 104a, 104b on each end of the spindle 12. The spindle capture members 104a, 104b capture opposite ends of the spindle and are respectively fastened to the side plates 10a, 10b, by means of bolts 106a, 106b. Consequently, the spindle capture members ground the spindle to the side plates 10a, 10b and hence, once the independent suspension has been mounted to a vehicle, to the vehicle chassis. In the previously described embodiment of the invention, described with reference to Figures 2 to 4, the inventor has observed a problem in that if the hinge tube does not run freely it can start to bind up which puts a torque on the spindle. The torque on the spindle may in turn cause loosening of the retaining bolts 29 which is of course highly undesirable. The embodiment of Figure 5 addresses this problem. A limitation of the embodiment of Figure 5 is that it no longer includes the camber adjustment cam 17 so that camber correction has to be made through replacing the standard bush 13 with a bush that has an offset camber correction built in.

[58] Embodiments of the present invention are able to make use of a single suspension arm rather than the “A” frame design of the prior art (shown in Figures 1A and 1B). Consequently, considerably more space is available beneath the vehicle for items such as water tanks. 2016101677 19 Sep 2016 11 [59] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term “comprises” and its variations, such as “comprising” and “comprised of” is used throughout in an inclusive sense and not to the exclusion of any additional features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

[60] Throughout the specification and claims (if present), unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms.

[61] Any embodiment of the invention is meant to be illustrative only and is not meant to be limiting to the invention. Therefore, it should be appreciated that various other changes and modifications can be made to any embodiment described without departing from the spirit and scope of the invention.

Claims (5)

1. The claims defining the invention are as follows:

   1. An independent suspension assembly for a trailer, said suspension assembly comprising: a trailer mounting subassembly for attachment to the trailer;; a tubular suspension arm extending from the trailer mounting subassembly, said tubular suspension arm being arranged to swing relative to the trailer mounting subsassembly; a stub axle extending laterally from the suspension arm; and a support subassembly fast with a remote end of the tubular suspension arm, the support subassembly adapted for supporting a resilient member; wherein a portion of the stub axle is fast with both the support subassembly and said tubular suspension arm.
2. 2. An assembly according to claim 1, wherein the stub axle is fast with a remote end of the tubular suspension arm at a location between a supporting portion of the support subassembly, adapted for supporting the resilient member, and the trailer mounting subassembly.
3. 3. An assembly according to any one claim 1 or claim 2 including a shock absorber coupled to the support subassembly, either to supplement the resilient member, during use, or as an alternative thereto.
4. 4. An assembly according to claim 2 or claim 3 when dependent upon claim 2, wherein the supporting portion for supporting the resilient member includes a supporting member that spans side plates of the support assembly.
5. 5. A trailer comprising an independent suspension assembly in accordance with any one of the preceding claims.