AU774930B2

AU774930B2 - Trailer coupling

Info

Publication number: AU774930B2
Application number: AU10039/01A
Authority: AU
Inventors: Henning F. Afflerbach; Reinhard Gottschling; Rudolf Dr. Staude
Original assignee: Cramer Kupplung GmbH and Co KG
Current assignee: GKN Walterscheid Cramer GmbH
Priority date: 2000-01-12
Filing date: 2001-01-03
Publication date: 2004-07-15
Anticipated expiration: 2021-01-03
Also published as: EP1116609A2; EP1116609A3; ZA200100280B; DK1116609T3; ATE318221T1; EP1116609B1; DE50012255D1; DE10000848A1; AU1003901A

Abstract

The tow-hitch assembly (8) has a hitch with a pin (2), attached to the rear end of the tractor vehicle. The pin fits into top and bottom bearings and is spring-loaded (7) downwards. A lever (5) may be rotated about a pivot to raise and lower the pin. And there is a catch (4), which may be rotated to lock the pin in its lowered position. The pin passes through a simple eye (6) in the end of the tow bar on the trailer, when it is its lowered position. A bellmouth (1) guides the end of the tow-bar into its coupling position when the tractor is backed onto the end of the tow-bar.

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventors: Address for Service: Invention Title: CRAMER KUPPLUNG GMBH CO. KG Dr. Rudolf Staude; Henning F. Afflerbach; Reinhard Gottschling CALLINAN LAWRIE, 711 High Street, Kew, Victoria 3101, Australia TRAILER COUPLING The following statement is a full description of this invention, including the best method of performing it known to me:- 03/01/01.tdl 1763.cs.doc,l -2- TRAILER COUPLING The present invention relates to trailer coupling.

A trailer coupling having a coupling throat, a coupling pin that can be lifted from and lowered into the coupling throat, at least one safety pin to secure the coupling pin lowered into the closed position against lifting, and a lifting mechanism for the coupling pin is known, wherein the coupling pin can be displaced only linearly between the open and closed positions and is guided in a non-rotatable manner. At the same time the lifting mechanism is used for the locking of the coupling pin in both positions, while in the locked position the coupling pin is locked by a toggle joint mechanism blocked in a form-locking manner. In the case of this known embodiment the torques generated by the coupled pullbar against the coupling pin are transmitted directly to the lifting mechanism, so that the lifting mechanism is subjected to torsional stresses. Moreover, the shearing forces produced by the pullbar are also directly transmitted from the coupling pin to the lifting mechanism, so that the lifting mechanism is subjected not only to torsional stresses but also to shear stresses. This results in considerable wear and reduced service life.

The object of the invention is to provide a trailer coupling having the construction described in the introduction that is characterised by increased functional safety and reduced wear while being cost-effective.

According to the present invention there is provided a trailer coupling with a coupling S"throat including: S: 25 a coupling pin that can be lifted from and lowered into the coupling throat, at least one safety pin to secure the coupling pin lowered into the closed position against lifting i and a lifting mechanism for the coupling pin, wherein the coupling throat is pivotably mounted about a substantially vertical pivoting axis in a mounting throat and wherein the coupling pin is rotatably mounted in the mounting throat about a vertical axis of rotation.

ooo• o •The trailer coupling of the present invention includes a coupling throat which is pivotably 0 mounted about a substantially vertical pivoting axis in a U-shaped mounting throat in a :manner known per se and a coupling pin which is rotatably mounted in the mounting throat about a vertical axis of rotation. Within the scope of the invention the pivoting axis for the 25/05/04,eh I 1763.spc,2

II

coupling throat and the axis of rotation for the coupling pin may coincide. A uniform torque transmission is achieved always while the lifting mechanism for the coupling pin is subjected neither to torsional nor to shear stresses.

Further preferable features of the invention are listed in the following. Thus, according to the invention, a locking latch is provided for locking and unlocking the pivoting movements of the coupling throat. The invention further teaches that the lifting mechanism for the coupling pin has a lifting fork that is engaged with the coupling pin.

According to a further proposal of the invention the lifting fork actuates not only the coupling pin but also the safety pin(s) and the locking latch. Accordingly, a multifunctional lifting fork is achieved. The locking latch will be actually controlled by means of the lifting fork. It assumes the unlocking function for the pivoting movement of the coupling throat. By virtue of a form-locking and force-locking movement of the lifting fork the locking latch is brought into its respective position so that to unlock the coupling throat or lock it by means of a locking latch spring acting on it. According to yet a further preferred feature the trailer coupling also includes an adjustable spring-loaded mechanism such that after a lateral deflection, the adjustable spring-loaded mechanism returns the coupling throat to a central position.

Consequently, a cost-effective trailer coupling having relatively few construction parts is realised by using multi-functional parts that operates functionally safely and is characterised by considerably reduced wear.

The invention is explained in detail in the following based on a drawing illustrating one embodiment only. They show in: Fig. 1 a vertical section through a trailer coupling according to the invention in the locked position, t: :30 Fig. 2 the subject matter of Fig. 1 in the unlocked position, and Fig. 3 the subject matter of Fig. 2 in the released position.

o. In the figures a trailer coupling is illustrated with a coupling throat 1 and with a coupling 25/05/04,eh 11763.spc3 -4pin 2 that can be lifted from and lowered into the coupling throat 1. Moreover, two diametrally opposite situated safety pins (not illustrated) are provided to secure the lowered coupling pin 2 in the locked position. The coupling pin 2 is actuated by means of a lifting mechanism. The coupling throat 1 is pivotably mounted about a substantially vertical pivoting axis S in a U-shaped mounting throat 3. The coupling pin 2 is rotatably mounted about a vertical axis D of rotation in the coupling throat 3, while according to the embodiment the pivoting axis S and the axis D of rotation coincide. Furthermore, a locking latch 4 is provided for the purpose of locking and unlocking the pivoting movement of the coupling throat 1.

The lifting mechanism for the coupling pin 2 has a lifting fork 5 that engages the coupling pin 2. The lifting fork 5 actuates the coupling pin 2, the safety pin(s) and the locking latch 4. Furthermore, the lifting fork 5 is acted upon by two closing springs acting independently from one another and can be actuated by a pivoting lever. They are not illustrated either. The lowering of the coupling pin 2 into the locked position is carried out automatically by introducing a pullbar 6 into the coupling throat 1 by virtue of removing the locking of the coupling pin 2 on the lifting fork. The coupling pin 2 is also under the load of a closing spring, e.g. a locking spring 7 in the direction of the locked position.

In addition, a separate coupling head 8 is realised that can be replaced independently from the coupling throat 1. The coupling head 8 basically includes the mounting throat 3, the lifting fork 5, the two safety pins and the actuating mechanism for the lifting fork The coupling pin 2, that can freely rotate, is subjected only to a small wear and makes a 25 fast closing process feasible. Two safety pins acting in a form-locking manner independently from one another prevent impact loads acting on the lifting mechanism and consequently on the lifting fork 5. The opening of the trailer coupling is carried out by actuating the lifting fork 5 by means of the pivoting lever that is situated on the spindle of the lifting fork 5. An automatic unlocking/locking of the coupling throat 1 •"30 during the closing/opening of the trailer coupling is achieved always.

Incidentally, the coupling pin 2 is guided in a two-part coupling sleeve with a saddle sleeve 9 and the saddle plate 10 is situated above, the saddle plate being fixed by means of a Q• retaining ring 11 and being able to be replaced when worn.

25/05/04,ch 1 1763.spc,4

Claims

1. A trailer coupling with a coupling throat including: a coupling pin that can be lifted from and lowered into the coupling throat, at least one safety pin to secure the coupling pin lowered into the closed position against lifting and a lifting mechanism for the coupling pin, wherein the coupling throat is pivotably mounted about a substantially vertical pivoting axis in a mounting throat and wherein the coupling pin is rotatably mounted in the mounting throat about a vertical axis of rotation.

2. The trailer coupling according to claim 1, wherein a locking latch is provided for locking and unlocking the pivoting movements of the coupling throat.

3. The trailer coupling according to claim 1 or claim 2, wherein the lifting mechanism for the coupling pin has a lifting fork that is engaged with the coupling pin.

4. The trailer coupling according to claim 3, wherein the lifting fork actuates the coupling pin, the safety pin(s) and the locking latch. The trailer coupling according to claim 3 or claim 4, wherein the lifting fork is acted upon by two closing springs acting independently from one another and can be actuated by a pivoting lever.

6. The trailer coupling according to any one of claims 3 to 5, wherein the lowering of the coupling pin into the closed position is carried out automatically by 25 introducing a pullbar into the coupling throat by virtue of removing the locking of the *e lifting fork on the coupling pin. i• 7. The trailer coupling according to any one of claims 1 to 6, wherein the coupling pin is under the load ofa closing spring. oo8. The trailer coupling according to claim 7, wherein the closing spring is a locking spring in the direction of the closed position.

9. The trailer coupling according to any one of claims to 8, wherein the 9. The trailer coupling according to any one of claims 1 to 8, wherein the 25/05/04,eh I 1763.spc,5 -6- coupling pin is guided in a two-part coupling sleeve with a saddle sleeve and a saddle plate is situated above, the saddle plate being fixed by means of a retaining ring and being able to be replaced.

10. The trailer coupling according to any one of claims 1 to 9, further including a separate coupling head that can be replaced independently from the coupling throat.

11. The trailer coupling according to any one of claims 1 to 10, wherein an adjustable spring-loaded mechanism is further provided such that after a lateral deflection said adjustable spring-loaded mechanism returns the coupling throat to a central position.

12. A trailer coupling, substantially as hereinbefore described with reference to the accompanying drawings. Dated this 2 5 th day May, 2004. CRAMER KUPPLUNG GMBH CO. KG By their Patent Attorneys: CALLINAN LAWRIE 25/05/04,eh 1763.spc,6