GB2205291A

GB2205291A - Removable towball for motor vehicles

Info

Publication number: GB2205291A
Application number: GB08813046A
Authority: GB
Inventors: Hans Riehle
Original assignee: ORIS METALLBAU KG RIEHLE H
Current assignee: ORIS METALLBAU KG RIEHLE H
Priority date: 1987-06-03
Filing date: 1988-06-02
Publication date: 1988-12-07
Anticipated expiration: 2008-06-02
Also published as: SE8802067L; NL191982B; NO882402D0; SE466995B; BE1001407A4; FR2616111B1; IT1219631B; DK167432B1; DK294188D0; NO165228B; IT8848036A0; NO165228C; FR2616111A1; SE8802067D0; DE3718552C2; NL8801138A; DE3718552A1; CH675859A5; GB8813046D0; NL191982C

Description

11 ' 1 1 1 1 Towing device for motor vehicles.

2205291 The invention relates to a towing device for motor vehicles, particularly but not exclusively for private cars, comprising a housing part fixed at the rear of the vehicle and a coupling ball neck with coupling ball adapted to be fixed separably therein, the end of the coupling ball neck engaging into a region of the housing part, and having laterally projecting studs which bear in form-locking fashion on arcuate housings in the housing part.

DE-OS 32 24 014 disclosed a towing device of this type in which automatic clamping of the ball neck occurs upon insertion into the housing part which is rigid with the vehicle, due to a clamping system which consists of a spring loaded push member mounted in the ball neck, articulating levers, a pivotable cam and a releasing pin fixed on the housing part. In contrast, the invention sets out to resolve the problem of providing a clamping system which can be manufactured at a favourable cost and in which all parts are seated only in or on the ball neck and with which onehanded operation is possible when releasing the ball neck from a housing.

According to the present invention there is provided a towing device for motor vehicles, comprising a housing part fixed at the rear of the vehicle and a coupling ball neck with coupling ball adapted to'be fixed separably therein, the end of the coupling ball neck engaging into a region of the housing party and having laterally projecting studs which bear in form-locking fashion on arcuate housings in the housing part and wherein there are provided means by which the ball neck, when inserted into the housing part, is automatically clamped to this latter by pressure on the studs in the direction against their housings, the means for automatically clamping the ball neck comprising, mounted in the ball neck, a bolt which is biased by thrust springs to bear in clamping fashion on a 0 2 ramp on the housing part and further comprising, likewise mounted in the ball neck and biased by a thrust spring, a releasing pin which, when the ball neck is separate from the housing, retains the bolt in a retracted position and then during the insertion process, releases it so that it can slide along an oblique surface on the housing part or abut thereon in order to assume its clamping position.

Advantageously, the bolt and the releasing pin can be operatively connected to each other by a ball which is pressed by the releasing pin in front of a shoulder of the retracted bolt and when the releasing pin is pushed back during the insertion process, is pressed by the bolt into a step on the releasing pin which in this position has a stepped diameter.

For retracting the bolt, it is possible to provide a pinion which engages a rack on the bolt and which is adapted to be driven by a hand wheel or a hand lever.

The hand wheel or the hand lever and- the pinion may be disposed on a shaft which is so mounted for longitudinal displacement transversely of the bolt that it can be pressed out of a first position in which it is positively locked with fhe bolt and moved against a thrust spring into a second position in which the interlock is removed although the teeth of the pinion are still not in engagement with the rack, such engagement being established in a third position.

Advantageously, at the end opposite the hand wheel or the hand lever, the shaft may project from the ball neck when the interlock of the shaft together with the bolt is removed, so that it is possible visually to check the interlock.

If, according to a further preferred feature of the invention, the studs on the ball neck engage from above into upwardly open housings on the housing part, the automatic clamping means can be disposed in the ball neck above the studs. Where the studs on the ball neck engage from below into downwardly open housings, the clamping means can be located in the ball neck, below the studs.

i 3 The bolt and the releasing pin may be disposed parallel with each other. Furthermore, the ball neck may be provided with a transverse bore which, on the one hand and in conjunction with the studs, serves as a housing for machining purposes while being on the other hand suitable as a means whereby the separated ball neck can be secured by a screw, for example in the boot of the vehicle.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a partly sectional side view of a ball neck inserted into a housing:

Fig. 2 is a section taken on the line II-II in Fig. 1, through the object shown in Fig. 1; Fig. 3 shows a section through the released ball neck and Figs, Figs. 4, 5 and 6 show sections through the ball neck taken on the line IV- IV in Fig. 3.

According to Figs. 1 and 2, there is for example, mounted on a crossmember 1 at the rear of a private car, a housing part 2 in which a ball neck 3 with coupling ball 4 is separably disposed. The end of the ball neck 3 is provided with a part spherical portion 5 by which it is inserted from below into a cylindrical recess 6 in the housing part 2. Furthermore, the ball neck comprises two laterally projecting studs 7 which rest from below in downwardly open half-round housings 8. In the position of the ball neck 3 as illustrated, this latter is gripped in the housing part 2 by a clamping system which is disposed in the ball neck. The clamping system consists essentially of a bolt 9 which is disposed in a bore 10 and which is biased by thrust springs 11 so that its conical end 12 is pressed against a ramp 13 in the housing part 2. A cylindrical pin 14 serves as a means of securing the bolt 9 in the bore 10 in such a way that it cannot rotate.

The rear end of the bolt 9 has a system of teeth constructed as a rack 15. According to Fig. 2, there is disposed in a bore 16 in the ball neck 3 and parallel with 4 the bolt 9 a releasing pin 17 which is biased by a spring 18 but which is secured against this'spring by a ball 19 disposed in a bore 20 between the bolt 9 and the releasing pin 17, engaging a stepped-diameter step 21 in the releasing pin. The ball 19 is held fast in this position by the bolt 9.

Above the bolt 9 and transversely thereto there is mounted in the ball neck 3, in a bore 32, a shaft 23 which by means of a hand lever 24 can be displaced against the action of a spring 25 so that it can both rotate and also be moved in an axial direction. The shaft 23 is provided with a pinion 26 and at the end which is opposite the hand lever 24, it has a piston-like part 27 of larger diameter. The free end of the shaft has a rounded head 28. Also disposed in the ball neck 3 is a transverse bore 29 which serves to allow the separated ball neck to be fixed in a storage position. Furthermore, in conjunction with the studs 7, it serves as a housing when the ball neck has to be machined. The front end of the releasing pin 17 is mounted in a bush 30 with a guard ring 32 disposed behind it. The bushes 30, 31 are fixed jointly by a cylindrical pin 33 (Fig. 1).

When the ballneck 3 is inserted into the housing part 2, all parts assume the positions shown in Figs. 1 and 2 in which the piston-like part 27 of the shaft 23 engages a recess 34 on the bolt 9. For releasing the ball neck, the shaft 23 is pressed sufficiently far into the ball neck that the pinion 26 engages the rack 15 on the bolt. By pivoting the hand lever 24 through 900, then, back against the action of the springs 11 sufficiently that the bolt loses its connection with the housing part 2. In this position, the ball neck drops out of the housing part 2 and at this moment the spring 18 presses the releasing pin 17 out of the ball neck so that the ball 19 is pressed in front of a step 35 on the bolt. The spring 25 releases the toothed engagement between rack 15 and pinion 26. The head 28 of the shaft 23 protrudes from the periphery of the ball neck. All parts assume the the bolt is pulled 1 i positions shown in Fig. 3.

When the ball neck 3 is inserted into the housing part 2, the releasing pin 17 strikes the housing part 2. The releasing pin is pushed back and the bolt which has been pressed forwards by the springs 11 pushes the ball 19 into the stepped portion 21 on the releasing pin and bears in clamping manner on the ramp 13, the piston-like part 27 of the shaft 23 engaging the recess 34 on the bolt 9 in a securing manner. The head 28 of the shaft 23 disappears in the ball neck as an indication that the clamping engagement has been established.

The individual positions of the shaft 23 are shown in Figs. 4 to 6. The position according to Fig. 4 corresponds to that in Fig. 2. The teeth are disengaged, the part 27 engages the recess 24 on the bolt 9. Fig. 5 shows the position according to Fig. 3 with the ball neck released and Fig. 6 shows the engagement of the teeth when pulling back the bolt 9.

For the bolt 9 and the releasing pin 17, it is possible according to the manner of construction to provide corresponding ramps on the housing part. It is also possible to dispose the releasing pin 17 transversely to the bolt 9.

In the event of the studs 7 on the ball neck 9 being suspended from above in housings on the housing part, then the clamping system is disposed above the studs in the ball neck so that the bolt presses the studs downwardly from above and into the housings.

1 1 6

Claims

CLAIMS:-

1. A towing device for motor vehicles, comprising a housing part fixed at the rear of the vehicle and a coupling ball neck with coupling ball adapted to be fixed separably therein, the end of the coupling ball neck engaging into a region of the housing part, and having laterally projecting studs which bear in form-looking fashion on arcuate housings in the housing' part and wherein there are provided means by which the ball neck, when inserted into the housing part, is automatically clamped to this latter by pressure on the studs in the direction against their housings, the means for automatically clamping the ball neck comprising, mounted in the ball neck, a bolt which is biased by thrust springs to bear in clamping fashion on a ramp on the housing part and further comprising, likewise mounted in the ball neck and biased by a thrust spring, a releasing pin which, when the ball neck is separate from the housing, retains the bolt in a retracted position and then during the insertion process, releases it so that it can slide along an oblique surface on the housing part or abut thereon in order to assume its clamping position.

2. A device according to claim 1, wherein the bolt and the releasing pin are operatively connected to each other by a ball which is pressed by the releasing pin in front of a shoulder of the retracted bolt and when the releasing pin is pushed back during the insertion process, is pressed by the bolt into a step on the releasing pin which in this position has a stepped diameter.

3. A device according to claims 1 or 2, wherein to retract the bolt a pinion is provided which engages a rack on the bolt and which is adapted to be driven by a hand wheel or a hand lever.

4. A device according to claim 3, wherein the hand 1 7 wheel or the hand lever and the pinion are disposed on a shaft which is so mounted for longitudinal displacement transversely of the bolt that it can be pressed out of a position in which it is positively locked together with the bolt, can be pressed against a thrust spring into a second position in which the interlock is cancelled out but the teeth of the pinion are still not engaged with the rack, such engagement being established in a third position.

5. A device according to claim 3 or 4, wherein at the end which is opposite the hand wheel of the hand lever the shaft protrudes from the ball neck when the interlock between the shaft and the bolt is removed.

6. A device according to any one of claims 1 to 5, in which the part of the ball neck adapted to be inserted into the housing part has a substantially vertical disposition during the insertion process, and wherein the studs on the ball neck engage from above into upwardly open housings on the housing part, and the automatic clamping means are disposed in the ball neck above the studs.

7. A device according to any one of claims 1 to 5, in which the part of the ball neck which is adapted to be inserted into the housing part has a substantially vertical disposition during the insertion process, and wherein the studs on the ball neck engage from beneath into housings which are open at the bottom and which are provided on the housing part, and the automatic clamping means are disposed in the ball neck under the studs.

8. A device according to any one of claims 1 to 7, wherein the bolt and the releasing pin are parallel with each other.

9. A device according to any one of claims 1 to 8, 1 Al.

X 8 wherein the ball neck is provided with a transverse bore.

10. A towing device for motor vehicles, substantially as described herein with reference to, and as illustrated in, the accompanying drawings.

1 Published 1988 at The Patent Off-ice, State House, 66/71 High Holborn, London WClR 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1/87.