GB2042449A

GB2042449A - Trailer coupling

Info

Publication number: GB2042449A
Application number: GB7943475A
Authority: GB
Original assignee: Slapvagnskopplingar AB
Current assignee: Slapvagnskopplingar AB
Priority date: 1979-01-02
Filing date: 1979-12-18
Publication date: 1980-09-24
Also published as: WO1980001640A1; SE7900032L; GB2042449B; NL7901127A; DE2951824A1; FR2448878A1

Abstract

For trailer couplings there are international agreements specifying that the coupling mouth intended for receiving a towing eye of the trailer shall have a vertical play allowing a certain vertical swinging movement of the connected towing eye (6). This play between the upper and the lower side of the towing eye (6) and the corresponding inner surfaces, respectively, of the coupling mouth, however, has earlier implied wear as well as rattle. The invention solves this problem in that the coupling bolt (8) introduced through the towing eye, has a resiliently mounted abutment element (28) intended for engagement with the towing eye and filling said play. <IMAGE>

Description

SPECIFICATION Trailer coupling The present invention relates to a trailer coupling intended for application on a traction vehicle for making possible the connection thereto of a trailer, said coupling having a housing with an opening, into which a towing eye of a drawbar of said trailer can be introduced into a coupling position, a coupling bolt mounted in the housing for movement from a withdrawn position in the housing to extend through the eye.

For couplings of this kind there are international agreements specifying that there shall be a vertical play in the coupling mouth allowing a determined vertical swinging motion of the towing eye. This play between the upper and lower sides of the towing eye and the corresponding upper and lower inner surfaces, respectively, of the coupling mouth, however, introduces heavy wear of the parts concerned as well as rattle.

One object of the invention is to solve this problem. According to the invention a trailer coupling has a housing with an opening into which a towing eye of a drawbar of said trailer can be introduced into a coupling position, a coupling bolt mounted in the housing for movement from a withdrawn position in the housing to extend through the eye, and a resiliently mounted abutment element intended for contact with the towing eye in a direction generally endwise of the bolt.

The invention may be carried into practice in various ways but several specific embodiments will now be described by way of example, with reference to the accompanying drawings, in which: Figures 1 and 2 show similar axial sections through a trailer coupling with a towing eye coupled thereto, the towing eye in Fig. 2 taking a sloping position; Figure 3 shows a view perpendicular to the views according to Figs. 1 and 2 of the coupling bolt included in the coupling; Figure 4 shows a side view partly in section, of a modified form of coupling bolt; Figure 5 shows a view perpendicular to the view in Fig. 4, and Figure 6 shows a side view, partly in section, of a further embodiment of the coupling bolt.

The trailer coupling of Figs. 1 and 2 has a coupling house 2. The coupling house 2 has an opening 4, into which a towing eye 6 at the end of a draw bar connected to a trailer is intended to be introduced to a coupling position as illustrated. In said coupling position the towing eye 6 is held by a coupling bolt 8.

The coupling bolt 8 has an upper portion 10, described more fully below, by means of which the coupling bolt is vertically movable in a bore 1 2 in the coupling house 2. A stop 14 is schematically indicated, by means of which the coupling bolt 8 is kept in the coupling position shown, with the lower end of the coupling bolt introduced into a bushing 1 6 in the lower part of the coupling house 2.

The further description will deal with the design of the coupling bolt, especially the upper portion 10 thereof. Further details of a trailer coupling of the kind in question are well known and need not be described more closely here.

The upper portion 10 of the coupling bolt has a spring retaining member including a wide head 18, a shaft 20 and screw end 22.

The screw end 22 is screwed into a threaded hole in an upper surface 24 of a coupling portion 26 of the coupling bolt intended for engagement with the towing eye. Said portion 26 has a central thicker part adapted to the dimensions of the towing eye.

The upper portion 10 of the coupling bolt further includes an annular abutment element 28, which is axially movable on the coupling bolt and on the shaft 20. Between the head 1 8 and the upper surface of the abutment element 28 an annular spring in the form of a solid rubber body 30 is arranged. The abutment element 28 has an inner abutment 32, which by engagement with a portion of the surface 24 limits the movement of the element 28 downwardly on the coupling bolt.

The element 28 on its lower end has two mutually opposite bevels 34, the function of which will be described more fully below.

The abutment element 28 in its lowermost position (Fig. 1) partly protrudes downwardly from the bore 1 2. The bevels 34 face forwards and backwards, respectively. The bushing 1 6 on its upper end has mutually opposite bevels 36 facing forwards and backwards respectively.

To allow for a certain vertical swinging movement of a draw bar connected to the coupling the inner height of the opening 4 has been chosen to allow for a certain amount of vertical play with respect to the towing eye of said connected draw bar. This play is filled with the downwardly protruding end of the abutment element 28. On vertical swinging movement of the draw bar and thereby tilting movement of the towing eye 6 around the central portion 26 of the coupling bolt, the abutment element 28 is pressed upwardly by the towing eye against the action of the annular spring 30, as shown in Fig. 2. In Fig.

2 it can be seen that the towing eye engages the front bevel 34 and the rear bevel 36.

During an upwardly tilting position of the towing eye it engages the rear bevel 34 and the front bevel 36.

It should be understood that the spring biased element 28 eliminates any play on the upper and lower sides of the towing eye independently of the vertical tilting position of the draw bar between its outer limit positions.

A lot of wear of the engagement surfaces of the coupling bolt and the coupling house, as well as rattle is thereby eliminated.

Figs. 4 and 5 show an embodiment of the coupling bolt which principally only differs from the embodiment according to Figs. 1-3 in that the rubber body 30 has been replaced by a stack 38 of cup springs arranged as illustrated.

The embodiment according to Figs. 4 and 5 operates in the same way as the embodiment of the preceding Figures.

In Fig. 6 a further embodiment of the coupling bolt is shown, which allows for free rotational movement by the coupling portion of the coupling bolt intended for engagement with the towing eye. Thereby the wear of the coupling bolt caused by sidewards movements of the drawbar in operation, becomes even around the periphery of the coupling portion of the coupling bolt.

More particularly the coupling bolt has a prolonged upper shaft portion 50 integral with the coupling portion of the coupling bolt.

Against the upper end of the shaft portion 50 an abutment head 52 is screwed as indicated at 54. Between an abutment 56 on the coupling bolt forming a transition to the shaft portion 50, and the abutment head 52 a vertically acting spring unit is rotatably jour nalled around the shaft 50 by means of lower and upper journals 58 and 60, respectively.

Said spring unit has an abutment element 62 with the same form and function as the abutment element 28 in the earlier embodiments, an annular rubber body 64 corresponding to the rubber body 30 according to Figs. 1 and 2 and an upper abutment 66, forming a seat for the journal 60. The rubber spring ring 64 can, of course, be replaced by a spring stack corresponding to the spring stack 38 according to Figs. 4 and 5.

The invention is, of course, not limited to the described and shown embodiments but can be modified within the scope of the claims. It should, however, be particuiarly emphasised that the embodiments having the abutment element and its spring arrangement carried by the coupling bolt, instead of having it connected to the housing, presents an unconventional and very advantageous solution of the problem of how to provide an elastic play-eliminating abutment for the vertical tilting movements of towing eye.

Claims

1. A trailer coupling intended for application on a traction vehicle for making possible connection thereto of a trailer, said coupling having a housing with an opening into which a towing eye of a drawbar of said trailer can be introduced into a coupling position, a cou pling bolt mounted in the housing for move ment from a withdrawn position in the hous ing to extend through the eye, and a resiliently mounted abutment element intended for contact with the towing eye in a direction generally endwise of the bolt.

2. A coupling according to Claim 1, in which the abutment element is carried by the coupling bolt.

3. A coupling according to Claim 1 or Claim 2, in which the abutment element is biased towards a lower position with respect to the coupling bolt by a spring carried by the coupling bolt.

4. A coupling according to any of Claims 1 to 3, in which the abutment element surrounds the bolt in an annular manner.

5. A coupling according to Claim 4, in which the spring is a solid spring body or an annular cup spring stack acting between the abutment element and an upper end abutment on said coupling bolt.

6. A coupling according to Claim 5 in which a portion of the coupling bolt intended for engagement with a towing eye is rotatably carried by the rest of the coupling bolt.

7. A trailer coupling substantially as specifically described herein with reference to Figs.

1 to 3; Figs. 4 and 5; or Fig. 6 of the accompanying drawings.