AU2004200868B2 - Suspension arm - Google Patents

Description

Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT (ORIGINAL) Name of Applicant: YORK TRANSPORT EQUIPMENT PTY. LTD. Actual Inventor(s): CLELIO RIZZO Address for Service: SANDERCOCK & COWIE SUITE 8C, 50-54 ROBINSON STREET DANDENONG VIC 3175 Invention Title: SUSPENSION ARM Details of Associated Provisional Application(s): No(s): Australian Provisional Application No. 2003900948 Filed: 3 rd March, 2003 The following statement is a full description of this invention, including the best method of performing it known to us: Fc2004-03-03,A:\488york.file.wpd,I - la TITLE: SUSPENSION ARM FIELD OF THE INVENTION 5 This invention concerns suspension arms for trucks and trailers with axle loads of the order of 8-15 tonnes. BACKGROUND OF THE INVENTION 10 Trailing arm suspension units make use of an air bag damped by a mechanical shock 2004-03-03,A:\485york.cap.wpd,I -2 absorber and although of straightforward mechanical construction are commonly fabricated. SUMMARY OF THE INVENTION 5 A method of making atrailing suspension arm of the type having an eye at one end, a pad for an air spring and an axle mount, commencing with a rectangular tubular blank, providing an eye at one end, tapering that end by making one or more excisions of tapering width in a pair of mutually opposite walls, bringing the remaining pair of walls 10 toward the edges of the excised portions and joining the edges permanently. The excised edges of the sidewalls are joined by welds. The taper may be 5*-100, preferably 8*. 15 A recess for the pad which seats the air spring may be excised from the upper wall of the tube at the distal end. A semi circular recess for the axle bush may be excised from either the upper wall or the lower wall of the arm. Such cutting operations are economic to perform on steel tube of the thickness and hardness used in this component. Rolled hollow section steel with a yield strength not less than 350MPa is preferred. 20 The apparatus aspect of provides a suspension assembly for a truck or trailer of the type having a suspension arm with a suspension eye at one end, an air bag at the opposite end and an axle mount there between, wherein the arm is made from rectangular section tube. 25 Preferably the end portion, distal to the suspension bracket, has diverging side walls and the upper and lower walls located between the diverging walls where part of the tube wall has been removed. The arm may have a conventional pin bore for the pin which supports the lower end of 30 the shock absorber. The eye of the arm which takes the fulcrum pin of the suspension hanger bracket may receive a standard bush fitting incorporating a rubber sleeve. 201 0-4+01,H Spcic ttnsyork.capamend.wpd2 -3 BRIEF DESCRIPTION OF THE DRAWINGS Certain embodiments of the invention are now described with reference to the drawings, in which: 5 Figure 1 is a perspective of a pair of suspension assemblies fitted to a chassis with an axle joining them showing the wheel hubs but no wheels. Figure 2 is a plan of a tube in the process of formation. 10 Figure 3 is a side view of the tube already machined ready to take the various components. Figure 4 shows the sequence of formation. 15 Figure 5 is a plan of the tube with the added components in position. Figure 6 is a side view of the tube in Figure 5. 20 Figure 7 is a plan of a suspension unit connected to the hanger bracket. Figure 8 is a side view of the assembly ready to receive the axle showing the reinforcing clip. 25 Figures 9 and 10 are perspective views of the reinforcing clip. DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS Referring now to the drawings, Figure 1 shows a suspension arm 2 as part of a general 30 arrangement on a truck chassis 4. The air bag 6 and the shock absorber 8 are conventionally attached. A 985mm steel tube 10, 6mm thick with a section of 150 x 150mm is recessed at the 2004-03-03,A:\485york. cap. wpd,3 -4 trailing end to provide a mount 12 for the air bag pan 14 (see Figures 4 and 5). An axle recess 16, a bore 18 for the shock absorber bush and the eye 20 at the leading end are cut. The upper wall 22 and lower wall 24 of the leading end on the tube are then laser cut to an M-configuration as shown in Figure 2. The edges of the cuts are ground to 300 to 5 allow full penetration of the subsequent weld. The side walls 26 are converged and welded to produce the precursor in the middle part of Figure 4. Web reinforcement 28 is welded beneath the air spring pan 14 and the pan is welded ready to receive the air spring assembly. The axle housing 30 is welded to recess 16. 10 The shock absorber bush 32 is welded in bore 18. A rubber sleeved arm mount 34 is fitted to the eye 20. The suspension arm is secured to the hanger bracket 36 as shown in Figures 7 and 8. In other non-illustrated embodiments, the tube thickness is 8 and 9mm thick. 15 Referring particularly to Figures 8, 9 and 10, a U-shaped pressed steel clip 38 has a flat base 40 and curved arms 42. The base has twin apertures 44 and bores 46 in each arm. These form sites for plug welds 48. Arcuate edge 50 corresponds to the curvature of housing 30 to which it is welded. 20 We have found the advantages of the above embodiment to be: 1. Manufacturing costs are reduced because the blanks are cut from stock without fabrication. 25 2. Torsional resistance is not reduced. 3. Underslung and over slung axles are possible exactly as in the prior art suspension arms. 30 It is to be understood that the word "comprising" as used throughout the specification is to be interpreted in its inclusive form, ie. use of the word "comprising" does not exclude the addition of other elements. 2004-03-03,A:\485york.cap.wpd.4 -5 It is to be understood that various modifications of and/or additions to the invention can be made without departing from the basic nature of the invention. These modifications and/or additions are therefore considered to fall within the scope of the invention. 2004-03-03,A:\485york.cap.wpd,5

Claims (10)

1. A method of making a trailing suspension arm of the type having an eye at one end, a pad for an air spring and an axle mount, commencing with a rectangular 5 tubular blank, providing an eye at one end, tapering that end by making one or more excisions of tapering width in a pair of mutually opposite walls, bringing the remaining pair of walls toward the edges of the excised portions and joining the edges permanently. 10

2. A method as claimed in Claim 1, wherein the end of the arm is excised to define an M-shaped configuration.

3. A method as claimed in Claim 2, wherein the edges of the excisions are ground to improve penetration of the subsequent weld. 15

4. A method as claimed in Claim 2, wherein the side walls of the tube adjacent the excised portions are converged such that the ground edges lie in apposition to receive weld metal. 20

5. A method as claimed in Claim 4, wherein the edges are ground to 25*-35*.

6. A method as claimed in any one of Claims 1-5, wherein a recess is excised in the upper wall of the trailing end of the arm in order to create a support surface for the air spring pad. 25

7. A method as claimed in any one of Claims 1-6, wherein an arcuate excision is made in the upper or lower wall of the arm for the axle housing.

8. A method of making a trailing suspension arm for a vehicle substantially as 30 herein described with reference to Figures 2, 3 and 4 or as modified by Figures 5 and 6.

2010-04-01,HASpecificationsiyk.capamend.wpd,6 -7

9. A trailing suspension arm precursor with an eye, a taper at the eye end, an arcuate excision for an axle mount and an excision for an air spring pad when made by the method claimed in any one of the preceding claims. 5 10. A trailing suspension arm for a vehicle when made from a precursor as claimed in Claim 9. 11. A vehicle suspension unit containing a trailing suspension arm as claimed in Claim 10.

10 12. A method as claimed in any one of Claims 7-11, wherein the connection between the arm and the axle is strengthened by provision of a reinforcement welded to a face of the arn and to the surface of the axle housing. 15 13. A method as claimed in Claim 8, wherein the reinforcement is a close-fitting clip which at least partially surrounds the arm and a substantial arc of the axle housing. 14. A trailing suspension arm precursor when made by the method of Claim 12 or 13. 20 15. A trailing suspension arm when made from a precursor as claimed in Claim 14. 2010-04-01,tSpecifications\yorkcapamend.wpcL7