AU603171B2 - Towing hitch - Google Patents

Description

7 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPEC IFICATILL 1 uNM

(ORIGINAL)

Class Int. Clasn Application Number: PH09616 and PI0459 Lodged: 22.12.1986 and 20.2.1987 0S@S

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Accepted: Published& [This document contains fher amonndrnents made win' Sc'tion 49 and is,, correct f 0 printing.

MAIL OFFICER Related Art

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U 55 0 S @5 4 Na,?e of Applicant: .Adlress of Applicant: ERIC HAYMAN SALES PTY. LTD.

5 Malonga Court, North Caulfield, Victoria, Australia ERIC HAYMAN Actual Inventor; Address for Service: EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: TOWING HITCH The following statement Is a full description of this Invention, including the best method of performing it known to us Sel of Company and signatures of iU Officersu prescribed by its Articles of Ausociatlcn.

WAYNE Mc MASTER Registered Patent Attorney.

TO: THE COMMISSIONER OF PATENTS.

Idwd. Wattrs Sons, 2.

TOWING HITCH The invention relates to a towing hitch, more particularly a moveable hitch of the type used to connect a vehicle to a trailer.

Moveable hitches are well-known in Australia and in their simplest form comprise a telescopic extension coupling of a trailer with elastomeric material interposed between the telescoped portions. This elastomeric material absorbs shocks caused by jolting of the trailer and minimizes transfer of the shocks to the towing vehicle. This is achieved by the elastomeric material deforming to allow limited transverse movement between the elements of the telescopic coupling. The amount of transverse movement possible is restricted by the compressive strength of the 15 elastomeric material.

a Another approach to minimising transmission of shock to the towing vehicle is disclosed in Australian patent No. 538,662. This arrangement substitutes a I horizontally pivoted towing hitch for the prior telescopic 20 arrangement. The hitch comprises a housing to which one end of a towing tongue is pivotally connected. A pair of springs of elastomeric material are interposed in the housing and bear upon the towing tongue from above and below. In use if the trailer encounters a bump and a shock 25 results, the towing tongue may deflect about the pivot either up or down transmitting the shock energy to the springs or elastomeric material.

Both of these known systems involve the towing tongue or hitch pivoting relative to the vehicle or trailer which whilst giving some absorbance to shock energy, nevertheless increases the angle of revolution of the towball in the encircling coupling. This excessive movement affects the safety of the entire hitch which is especially critical when towing a trailer on rough roads where excessive downward and upward movement of the hitch is likely to take place. Consequently these known hitches are suitable primarily for use on conventional road surfaces.

Inventors Paragraph 2 should be completed by showing detiL R North....Caul.f ,...Vic.tor a "The said (Name of app cant) is thi of Ju n 1 the as 5 th of the said (Nameof Inventor Signature (6) To: THE COMMISSIONER OF PATENTS.

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It is well recognized in the towing industry that there must be a proper weight distribution over the axles of the trailer, upon the hitch and upon the towing vehicle otherwise the towing vehicle may become unmanageable and accidents result. With conventional rigid hitches this weight distribution is achieved by the use of weight distribution bars passing from the hitch to distant portions of the trailer. These weight distribution bars cannot be effectively used with the foregoing moveable hitches as the resilient pivot mechanism inhibits the weight redistribution.

With the above in mind investigations took place t into minimizing the relative rotation of the towing ball in the trailer coupling to stabilize moveable hitches whilst 15 retaining their shock obsorbing qualities.

Accordingly there is provided a moveable hitch for connecting a first vehicle to a second vehicle, comprising a dsp\cc.A pair of membersijdxp#s generally parellel to one another and connected together by at least two arms displaced 20 relative to each other along the members, each arm pivotally engaging both members to permit substantially parallel movement of one of the members relative to the other of the members, resilient means interposed between the members to dampen the substantially parallel movement therebetween, 25 first connector means connecting one of the members to the first vehicle and second connector means connecting the other of the members to the second vehicle.

Thus, in use the members may move relative to one another in the vertical direction. The linkage arrangement eliminates radial pivoting of the coupling attachment in relation to the tow vehicle.

Further, whilst permitting shock absorbion of vertical movement the arrangement still retains full use of commonly available weight distribution hitches without affecting their utility. More partcularly in use the arm at the top of the hitch pushes forward toward the towing vehicle whilst the bottom arm of the hitch pulls away from i :i ij l i 4.

the vehicle so torsion is applied to effect the required weight distribution over the wheels.

In a first preferred embodiment each of the members has one or more projections protruding towards each other and the resilient means is interposed between the projections.

In a second preferred embodiment at least one of the spaced arms has a projection intermediate the ends thereof and the resilient means is interposed between the projection and one of the members.

e In a third preferred embodiment the arms are connected to the members by fixing means which pass through ~the arms, the members and protrude from the members.

Additional arms may be connected to the members on those 15 parts of the fixing means which protrude from the members.

Typically the fixing means are nut and bolt assemblies.

Where severe road conditions or difficult terrain is anticipated it is possible to adjust the freedom of the pivoting arms by incorporating friction material between the 20 arms and the members.

Preferably the resilient means are springs or Selastomeric material with means to adjust their compression in relation to the tow load to maintain towing attachment in an optimum position thus ensuring a maximum upward and 25 downward movement. This adjustment can be achieved by any 0 suitable means, for example, the ends of the members can be provided with threaded openings to receive bolts which contact and bear against the resilient means to adjust its compression. Similarly adjustment can be achieved by an alternate means of spacers placed either side of the projection.

Various features of the invention will now be illustrated with reference to the drawings in which: Figure 1 is a side view of a moveable towing hitch of the invention.

Figure 2 is a cross-sectional view A-A of the towing hitch of Figure 1.

ii Figure 3 is a side view of an alternate form of a moveable towing hitch of the invention.

Figure 4 is a cross-sectional view B-B of the towing hitch of Figure 3.

Figure 5 is a side view of a further form of a moveable towing hitch of the invention.

Figure 6 is a cross-sectional view C-C of the towing hitch of Figure In the drawings, like components are designated with like numbers and unless specified each operate in similar fashion.

As shown in the drawings a flexible hitch is provided having a side member 1 attached rigidly via bar 13 S" to a towing vehicle (not shown). Pivot links 2 are attached S 15 at one end to side members 1 and at their other end to a °front member 3. Front member 3 can be attached to conventional linkages of the types nominated as 4 and The trailer (not shown) is capable of attachment to these couplings with or without weight distribution devices.

20 Typically a standard trailer ball 6 is utilized.

In the embodiment shown in Figures 1 and 2, front member 3 is provided with an extension 3' and springs 7 are provided above and below that extension. Springs 7 are held in position by adjusting screw 8 located at either end of 25 side member i1. By turning adjustment screw 8 springs 7 can be adjusted to set the load required.

As more clearly shown in Figure 2 pivot links are attached to side member 1 via bolts 10. Between side member 1 and link 2 is a pad of friction material 9 to dampen the pivot movement of link 2 relative to front member 1. On the outer side of link 2 resilient material 11 and washers 12 are situated about bolt 10. To change the pivot freedom of link 2 with respect to side member 1 bolt 10 is either tightened or loosened.

As shown in Figure 1 side member 1 may be provided at one end with a removable plate 15 held in position by 6.

bolt 14 giving ready access to install or replace springs 7.

Plate 15 carries adjustment screw 8.

An alternate form of hitch is shown in Figures 3 and 4, where front member 3 is provided with an extension at one end thereof. Side member 1 is provided with an extension 16. A spring 7 is located between extension and 16. Spring 7 is held in position by bolts 8 and retaining washers 17 located at extensions 15 and 16. By turning screw 8, spring 7 can be adjusted to set the load required.

so.. *A further alternate form of moveable hitch is shown i.1,o" in Figures 5 and 6 in which one end of spring 7 is still *located and attached to extension 16. However, the other end of spring 7 is held to move with the movement of pivot 15 links 2. This is achieved by member 18 which communicates between adjacent pairs of pivot links 2 and which has upper bolt 8 threaded therethrough. By rotating bolt 8 in member 18, tension in spring 7 may be adjusted. Adjustment of spring 7 may be further affected by use of suitable spacing

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20 elements such as spacing washers or plates.

The moveable hitch of this invention by reason of S* it ensuring verticle movement and dampening between side member 1 and front member 3, reduces unwanted pivoting of the coupling attachment in relation to the tow vehicle. As 25 such this moveable hitch is particularly adapted for use when towing over rough or difficult terrain.

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Claims (3)

1. 7. THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A moveable hitch for connecting a first vehicle to a second vehicle, comprising a pair of members disposed generally parallel to one another and connected together by at least two arms4despOsfr relative to each other along the members, each arm pivotally engaging both members to permit substantially parallel movement of one of the members relative to the other of the members, resilient means interposed between the members to dampen the substantially parallel movement therebetween, first connector means connecting one of the members to the first vehicle and t.f, second connector means connecting the other of the members to the second vehicle. 2. A moveable hitch according to claim 1 wherein each of the members has one or more projections protruding towards each other and the resilient means is interposed between the projections. 3. A moveable hitch according to claim 1 wherein at least one of the opaeed arms has a projection intermediate the ends thereof and the resilient means is interposed between the projection and one of the members. •f 4. A moveable hitch acording to any one of claims 1 to 3 wherein the arms are connected to the members by fixing means which pass through the arms, the members and protrude from the members. A moveable hitch according to claim 4 wherein additional arms are each connected to the members on those parts of the fixing means which protrude from the members. 6. A moveable hitch according to either claim 4 or wherein the fixing means are bolt and nut assemblies. /-9
2. 9- XrjJ^ 8. 7. A moveable hitch according to any one of claims 4 to 6 wherein friction washers are located on the fixing means between the arms and the members. 8. A moveable hitch according to any one of claims 1 to 7 wherein the resilient means is a spring or elastomeric material. 9. A moveable hitch according to any one of claims 2 to 8 wherein the resilient means includes means to adjust the tension in the resilient means. 5
3. 10. A moveable hitch substantially as hereinbefore .e described with reference to the accompanying drawings. 0 DATED this 7th day of December, 1987. ERIC HAYMAN SALES PTY. LTD. V Pts\ ST Patent Atto s, S6jss.LA G 50 Quee reet, 2s z Me L ne, Victoria, WMcM:BB (3.27) 4 y 5 C