GB2143485A

GB2143485A - Trailer coupling link

Info

Publication number: GB2143485A
Application number: GB08417079A
Authority: GB
Inventors: Hans Riehle
Original assignee: ORIS METALLBAU KG RIEHLE H
Current assignee: ORIS METALLBAU KG RIEHLE H
Priority date: 1983-07-19
Filing date: 1984-07-04
Publication date: 1985-02-13
Also published as: GB2143485B; DE3325929A1; BE899686A; FR2549421B1; GB8417079D0; SE8403774D0; IT8448144A0; SE453174B; DK156507C; DK348584A; SE8403774L; DK156507B; IT1177699B; DK348584D0; NL8401207A; CH664933A5; FR2549421A1

Abstract

A trailer coupling link comprises a trapezoidal four-link linkage 2,3,4, used to achieve a virtual centre of rotation displaced forwards in the direction of the centre of gravity of the towing vehicle, one link 2 of the said linkage being arranged so as to be capable of limited pivoting about a longitudinal axis on a flange element 5 which can be bolted on below the trailer drawbar 14, and another link 3 is formed by a housing element 6 mounted on the coupling ball 16 and, with the aid of grooves 21 overlapping projections 22 which extend laterally from the ball neck 15, can be fixed so as to be immovable about the perpendicular axis passing through the coupling ball. The coupling link may be removed to enable a conventional coupling between the towing vehicle and trailer for short and slow journeys. Links 3,4 are connected by ball joints 9. <IMAGE>

Description

SPECIFICATION Coupling link between a towing vehicle and a trailer The invention relates to a coupling link between a towing vehicle, particularly but not exclusively a passenger car, the rear of which is provided with a coupling ball on a ball neck, and the drawbar of a trailer, the coupling link including a trapezoidal linkage having four links in which one of the two links which are in parallel comprises a housing element and a cup, which element, in use, extends over the coupling ball and which is adapted to be secured to the latter or to its ball neck, and the other of the two links is associated with the trailer drawbar and is articulated in a manner permitting within predetermined limits, pivotal movements about the longitudinal axis of the drawbar.

Coupling links of this type, which are known for example from German Offenlegungsschrift 31 49 700, have the advantage over conventional trailer couplings, in which a cup provided on the trailer drawbar extends over the coupling ball on the towing vehicle, in that the virtual centre of rotation or pivot of the coupling link is displaced in the direction of the centre of gravity of the towing vehicle so that pivot-free travel is ensured for the trailer and, as a result, high travelling speeds are possible for the towing vehicle/trailer combination.

The problem underlying the invention is to design a coupling link of this type in such a manner that drawbars on trailers having existing cups for the coupling balls do not need to be extensively modified but merely to be supplemented, and the ball neck of the coupling ball only requires a slight modification which does not interfere with the normal coupling of a trailer and can therefore be provided on all ball necks.

According to the present invention there is provided a coupling link between a towing vehicle, the rear of which is provided with a coupling ball on a ball neck, and the drawbar of a trailer, comprising a trapezoidal four-link linkage having two links in parallel one of which parallel links is a shorter link and comprises a housing element and cup adapted to engage over the coupling ball and the longer link is associated with the trailer drawbar and mounted so as to be pivotable within predetermined limits about the longitu dinal axis of the drawbar, respective ends of said two links being connected by respective control arms, said longer link being articulated on a flange element adapted to be secured from below to the housing element of the drawbar and the housing element which forms said shorter link engaging, when the cut is fitted on the coupling ball, by means of grooves therein over projections which protrude laterally from the ball neck to prevent pivotal movement of said shorter link relative to the ball.

It is an advantage that existing trailers can be used without any substantial constructional modification, but merely by providing an additional component, for pivot-free rapid travel of a towing vehicle. The housing element which forms the link of the trapezoidal linkage on the towing vehicle is used like a cup and like the latter, after being fitted on the coupling ball, is secured by an angle lever to prevent it from lifting. The grooves which are provided on the sides of the housing element extend over corresponding projections on the ball neck when the latter is fitted on the coupling ball. It is thus ensured in a simple manner and without any further addition that the housing element cannot be pivotted relative to the coupling ball.

In a preferred embodiment bf the invention the link of the trapezoidal linkage which is associated with the drawbar can be mounted on the flange element by means of a tapered roller bearing so as to be free from play in the longitudinal direction of the drawbar: The control arms which connect the two parallel links may be articulated on the longer link associated with the drawbar by means of tapered roller bearings, and the control arms may be articulated by means of ball joints on the housing element which forms the other, shorter, link and which is provided with the cup.

The control arms may be I-shaped in crosssection and, to permit a relatively large pivotal displacement of the trailer relative to the towing vehicle, the arms may be curved outwards from the points of articulation on the link associated with the drawbar.

The projections which are provided on the sides of the ball neck for engaging the housing element may be forged on the ball neck.

However, they can also be formed by a bolt or pin passing through the ball neck.

An embodiment of a coupling link according to the invention will now be described, by way of example, with reference to the drawing, in which: Fig. 1 shows a plan view of the coupling link, Fig. 2 shows a section through the coupling link along the line ll-ll in Fig. 1 Fig. 3 shows a section along the line Ill-Ill in Fig. 2, and Fig. 4 shows a section along the line IV-IV in Fig. 2.

According to Fig. 1. the coupling link consists of a trapezoidal four-link linkage 1 having links 2, 3 parallel to one another and two control arms 4 connected to these links. The longer of the links 2, 3, namely the link 2, is articulated on a flange element 5 which is adapted to be bolted from below to a drawbar of a trailer. The shorter link 3 is formed by a housing element 6 which has a cup 7 adapted to be fitted on a coupling ball mounted on a ball neck at the rear of a towing vehicle. The connection between the control arms 4 and the link 2 is produced by tapered roller bearings 8 whilst the connection between the control arms 4 and the web 3 or the housing element 6 is achieved by ball joints 9 which permit tilting or rocking movements of approximately 20 in both directions.

As shown in more detail in Fig. 2, the link 2 is articulated on the flange element 5 by means of a tapered roller bearing 10 in such a manner that freedom from play is provided in the longitudinal direction of the flange element 5 by a nut 12 located under a cover 11, but the link 2 can perform pivoting or swivelling movements through approximately 25 in both directions about the longitudinal axis of the tapered roller bearing. With the aid of bolts 1 3 the flange element 5 can be fastened to the front end of a drawbar 14 of a trailer in such a manner that the parts which are normally provided for the coupling of the drawbar to a coupling ball are not adversely affected.To connect the linkage 1 to a coupling ball 1 6 seated on the end of a ball neck 1 5 at the rear of a towing vehicle, there is provided the housing element 6 which contains the cup 7 and forms the link 3 with ball joints 9 for the control arms 4 and in which a conventionally designed pivotting iever 1 7 and appropriate operating and locking means 18, 19 are mounted.

As is also shown in Fig 3, the housing element 6 has side wall ections 20 which extend downward next to the cup 7 and which are connected to one another in the direction of the towing vehicle. The wall sections 20 are provided at the bottom with open grooves or recesses 21 which, when the housing element .6 is fitted on the coupling ball 16, extend over projections 22 formed by a bolt or pin in the ball neck 1 5. During fitting the housing element 6 is automatically located by the projections 22 engaging the grooves so that it is no longer able to perform any movement relative to the ball neck 1 5 or the coupling ball 1 6.

It is evident from Fig. 4 that the ball joints 9 for the control arms 4 are secured to the housing element 6 from below by means of bolts 23.

The control arms 4 according to Fig. 2 are advantageously an I-shaped cross-section.

However, they may also be provided with cross-sectional forms such as those used in motor vehicle steering components which are subject to high stesses.

In order that the maximum possible pivotal movement of the trailer relative to the towing vehicle may be achieved, the control arms 4, as shown in Fig. 1, are each curved outwards in the area of the points of articulation on the link 2 so that, as can be seen from the broken lines in Fig . 1, deflections of approximately 90 are made possible. The dimensional proportions of the links 2, 3 relative to one another as shown in Fig 1. and the lengths of the control arms 4 allow the virtual centre of motion 24 of the trailer relative to the towing vehicle to be moved forward, far under the towing vehicle in the direction of its centre of gravity.

Claims

1. Coupling link between a towing vehicle, the rear of which is provided with a coupling ball on a ball neck, and the drawbar of a trailer, comprising a trapezoidal four-link linkage having two links in parallel one of which parallel links is a shorter link and comprises a housing element and cup adapted to engage over the coupling ball and the longer link is associated with the trailer drawbar and mounted so as to be pivotable within predetermined limits, about the longitudinal axis of the drawbar, respective ends of said two links being connected by respective control arms, said longer link be articulated on a flange element adapted to be secured from below to the housing element of the drawbar and the housing element which forms said shorter link engaging when the cup is fitted on the coupling ball, by means of gooves therein over projections which protrude laterally from the ball neck to prevent pivotal movement of said shorter link relative to the ball.

2. A coupling link according to claim 1, wherein said longer link is mounted so as to be free from play in the longitudinal direction of the drawbar on the flange element by means of a tapered roller bearing.

3. A coupling link according to claim 1 or 2, wherein the control arms which connect the two links are articulated on said longer link by means of tapered roller bearings.

4. A coupling link according to any one of claims 1 to 3, wherein the control arms are articulated on the housing element which forms said shorter link and which is provided with the cup by means of ball joints.

5. A coupling line according to any one of claims 1 to 4, wherein the control arms are Ishaped in cross-section.

6. A coupling link according to any one of claims 1 to 5, wherein the control arms are curved outwards from the points of articulation on said longer link.

7. A coupling link according to any one of claims 1 to 6, wherein the projections which are provided on the sides of the ball neck are forged on the latter.

8. A coupling link according to any one of claims 1 to 6, wherein the projections provided on the sides of the ball neck are formed by a bolt or pin passing through the ball neck.

9. A coupling link for connecting a coupling ball on a towing vehicle with a drawbar on a trailer, substantially as described herein with reference to and as illustrated in the accompanying drawings.