GB2204548A

GB2204548A - Ball and socket coupling devices

Info

Publication number: GB2204548A
Application number: GB08810434A
Authority: GB
Inventors: Godfrey Wyndham Boxall
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-05-08
Filing date: 1988-05-03
Publication date: 1988-11-16
Anticipated expiration: 2008-05-03
Also published as: GB2204548B; DE3832633A1; GB8810434D0; GB8710970D0

Description

2204548 BALL AND SOCKET COUPLING DEVICES This invention relates to

ball-and-socket coupling devices for interconnecting a vehicle and a trailer.

Ball-and-socket coupling devices are conventionally used in a number of vehicle/trailer combinations which are permitted to travel on public highways, the most popular such combination being a motor car and caravan. At low road speeds such combinations are generally safe but this tends not to be the case at high road speeds unless the coupling device incorporates some form of stabiliser.

Stabilisers tend to dampen caravan movements from adversely affecting the motor car and controlled steerability thereof.

It is an object of the present invention to provide a new and improved form of ball-and-socket coupling device incorporating a stabiliser.

According to the present invention there is provided a ball-and-socket coupling device comprising a first member including a ball element, a second member including a socket element dimensioned to receive the ball element and a displaceable locking element for inhibiting unwanted release of the ball element from the socket element, and wherein the improvement comprises a stabiliser comprising means mounted in the socket element and adapted, in use, to impose a downwardly-directed force against the ball element in a vertical plane towards the geometric centre 1 h of the recess formed by the socket element and at an angle inclined to the vertical lying within the range 300 to 600 It is preferred that the angle referred to is 45. It is also preferred that the magnitude of the force be variable and capable of being manually set at a known level when the members of the coupling device are interconnected.

By virtue of the present invention the coupling device when in use with a vehicle/trailer combination attenuates both pitching and yawing movements and thereby improves steerability of the vehicle and increases safety of the combination.

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

Fig. 1 is a sectional view taken in a vertical plane of a ball-and-socket coupling device according to the present invention; and Fig. 2 is a view of a detail.

As is shown in Fig. 1 of the drawings a ball-andsocket coupling device 10 comprises a first member 11 including a ball element 12 and a second member 14 including a socket element 15 which is dimensioned to receive the ball element 12. The ball element 12 is generally spherical and constitutes about 90% of.a sphere the remaining 10% of which is connected integrally with a I A er \ rod-like support 11A which conventionally is L-shaped and terminates in a bracket for bolting to a vehicle.

The second member 14 includes a support end 14A which conventionally is connected to a trailer and the socket element 12 has a cavity which forms part of a sphere, a displaceable locking element 16 being provided as part of the member 14 and which is actuated by a handle 17 to enable the ball element 20 to be entered into the socket element 15 when the locking element is displaced from the rig. 1 position and to prevent or inhibit unwanted release of the ball element 12 from the socket element 15 when the locking element 16 is in the Fig. 1 position. For this purpose locking element 16 is in the form of a tongue extending through a slot formed in the member 14 and intersecting with the socket element 15, the tongue being provided with a dished surface 16A against which the ball element 12 seats as is shown in Fig. 1. Operation of the locking element 16 is effected by pivotal movement of the handle 16 which is provided with a detent arrangement (not shown) capable of locking the handle in the Fig. 1 position during normal use of the coupling device 10.

The Fig. 1 sectional view is taken in a vertical plane and the equatorial plane of the ball element 12 is denoted 18 whilst the azimuthal axis of the ball element 12 is denoted 19 and these axes intersect at the geometric centre 20 of the ball element 12 and of the recess formed by the socket element 15 in view of the fact that the spherical surfaces of elements 12 and 15 are of almost the same curvature to minimise play between elements 12 and 15.

In accordance with the present invention a stabiliser 25 is provided for the device 10, the stabiliser 25 comprising a component 26 mounted in the socket element 15 and arranged to impose a downwardly directed force against the ball element 12 towards the centre 20, the force being inclined at an angle A to the azimuthal axis 19 where angle A lies within the range 301 to 601. Specifically as is illustrated in Fig. 1, and in greater detail in Fig.

2, one example of the component 26 comprises a hollow piston 27 slidably mounted within a housing 28 which is secured or may be integral with the member 14 and the hollow piston 27 contains a body of hydraulic oil 29 which may be pressurised by a secondary piston 30 secured to a rod 31 which extends through an aperture in housing 28 to terminate in a hand wheel 32, the rod 31 making a screw threaded connection with the housing 28. The end face 33 of the hollow piston 27 is spherically dished and is adapted to engage the ball element 12 with a force whose magnitude is variable and which is capable of being set at a known level by manual operation of hand wheel 32. For this purpose an indicator disc may be affixed to housing 28 whereby a reference mark on hand wheel 32 can be aligned with a specific indicator marking on the disc.The body -1 IN 1 29 of hydraulic oil whilst substantially non-compressible may provide a minimal degree of compressibility arising from air inclusions. It will be seen that in this specific arrangement the force which is imposed by the stabiliser 25 on the ball element 12 is inclined at the angle A where A = 45 and accordingly the stabiliser attenuates both pitching and yawing movements of the trailer during their transmission to the vehicle via the coupling device 10 and thereby improves steerability of the vehicle and increases safety of the combination.

Fig. 2 illustrates the principal components of the stabiliser 25 in slightly greater detail from which it will be seen that it is preferred that housing 28 be in the form of a cylindrical body 28A capable of making a screwthreaded connection with an aperture formed in the first member 14 so that the stabiliser can be retro-fitted to an existing first member 14.

It will of course be appreciated that the magnitude of the force imposed by the stabiliser 25 need not be set manually nor need it be set at a constant level and it is within the scope of the present invention to set the magnitude of the force by a servo device from signals generated by a pitch sensor associated with the coupling device. It will also be appreciated that the present invention need not utilise the body of oil 291but may provide direct non- resilient force on the ball element 12.

If resiliency is required a mechanical spring or suitable plastic or rubber compound may be provided in place of the body of oil 29.

k IS 1 1

Claims

1. A ball-and-socket coupling device comprising a first member including a ball element, a second member including a socket element dimensioned to receive the ball element and a displaceable locking element for inhibiting unwanted release of the ball element from the socket element, the improvement comprising a stabiliser comprising means mounted in the socket element and adapted, in use, to impose a downwardly directed force against the ball element in a vertical plane towards the geometric centre of the recess formed by the socket element and at an angle inclined to the vertical lying within the range 301 to 60.

2. A ball-and socket device as claimed in claim said angle is 451.

wherein

3. A ball-and-'socket coupling device as claimed in either preceding claim, wherein the magnitude of said force is variable and capable of being manually set at a known level.

4. A ball-and-socket device as claimed in claim 3, wherein the magnitude of said force is varied by a hollow piston slidably mounted within a housing in said second member, said hollow piston containing an hydraulic fluid pressurised by a secondary piston position-adjustably connected via a screw-threaded rod to said second member.

5. A ball-and-socket device as claimed in any preceding claim, wherein the first member is adapted for connection to a vehicle and the second member is adapted for connection to 1 a trailer, whereby in use the device attenuates trans- mission to the vehicle of both pitching and yawing movements to thereby improve steerability of the vehicle.

6. A ball-and-socket.device as claimed in claim 1, and substantially as hereinbefore described with reference to the accompanying drawing.

Published 1988 at The Patent Office, State House, 66171 High Holborn, London WCIR 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.