GB2098557A - Ball and socket coupling device - Google Patents

Abstract

A coupling device defining a socket for a coupling ball has a retainer 15 for retaining the ball in the socket. A key-operated plug lock 38 is inserted into an aperture in a housing of the device to engage the retainer and prevent movement of the retainer to a releasing position. Movement of the retainer to its release position is additionally prevented by engagement with a face 29 of an operating member 19. A latch 31 maintains the operating member 19 in the illustrated position. The plug lock 38 may be replaced by a combination lock or a padlock. <IMAGE>

Description

SPECIFICATION Ball and socket coupling device This invention relates to a coupling device of the kind, hereinafter called the kind specified, having a body defining a socket for receiving a coupling ball, a retainer movable relative to the body between a closed position in which it is capable of retaining the ball in the socket and an open position in which it permits the ball to be moved into and out of the socket, and an operating member movable relative to the retainer between an operative position in which the operating member prevents movement of the retainer from the closed position and an inoperative position in which the operating member permits movement of the retainer to the open position.

In British Specification No. 1,556,525, there is described a coupling device of the kind specified having a pawl pivoted on the operating member and a removable lock which can lock the pawl against pivoting relative to the operating member.

Whenthe pawl is locked in this way, it engages a boss on a housing of the device to obstruct movement of the operating member from the operative position.

According to the present invention, a coupling device of the kind specified has a lock engageable with the retainer to obstruct movement of the retainer from the closed position, the lock being operable to release the retainer for movement to its open position.

An example of a coupling device embodying the invention will now be described, with reference to the accompanying drawings, wherein: FIGURE 1 shows a side elevation of a coupling device, certain parts being broken away; and FIGURE 2 shows a plan view of the coupling device on an enlarged scale.

The coupling device shown in the drawings comprises a body 10 defining a downwardly open socket 11 for receiving a ball 12 mounted on a towing bracket of a motor vehicle (not shown).

The body includes a tubular portion 13 spaced rearwardly from the socket 11 and which, when the device is in use, co-operate with the draw bar of a trailer to mount the device on that draw bar (not shown). Generally, the draw bar will include an overrun brake-actuating device to which the coupling device will be secured.

A retainer 1 5 is mounted in the body 10 for pivotal movement relative thereto about a retainer axis 16 which is horizontal and transverse to the length of the body 1 0. The retainer has a partspherical concave face 1 7 and is movable between a closed position shown in Figure 1, in which the retainer retains the ball 12 in the socket 11 or obstructs insertion of the ball into the socket, and an open position in which the face 1 7 occupies the position indicated by the broken line and in which the retainer permits movement of the ball into and out of the socket. A torsion spring 1 8 acting between the retainer and the body biases the retainer to its open position.

To prevent movement of the retainer 15 to its open position during towing, there is provided an operating member 1 9 which is mounted on the body for pivoting relative thereto about an operating axis 20 spaced upwardly from and forwardly from the retainer axis 1 6. The body 10 comprises a pair of upright walls 21 and 22 which are disposed above the socket 11, are spaced apart laterally of the device and extend from a position above the socket rearwardly to the tubular portion 13. At their rear ends, the walls 21 and 22 are joined together by a transverse web 23. The operating member is carried on a pivot pin 24 which extends between the walls 21 and 22.

Two torsion springs 25 and 26 act between the operating member 19 and the body 10 to bias the operating member towards an operative position shown in Figure 1. The operating member includes a handle 27 which lies above the body 10 and by means of which the operating member can be pivoted to an inoperative position indicated by a broken line in Figure 1. A pin 28 carried by the walls 21 and 22 extends through a slot in the operating member to limit the feedom of the operating member for pivotal movement relative to the body.

The retainer 1 5 projects upwardly from the axis 1 6 through an aperture in the body 10 into the space between the walls 21 and 22 where the retainer is engaged by the operating member.

When the retainer is in its closed position, the operating member is urged by the springs 25 and 26 to the operative position in which a curved face 29, which is eccentric with respect to the operating axis 20, engages a generally forwardly facing surface of the retainer to prevent pivoting of the retainer in the anti-clockwise direction, as viewed in Figure 1. Movement of the operating member under the action of its springs 25 and 26 is limited by the retainer.

A latch 31 is mounted on the operating member 1 9 at one side thereof for pivoting relative thereto about a latch axis 30. One end portion of the latch protrudes above the handle 27, where it can readily be acted on by the thumb of a user who grips the handle with one hand. An opposite end of the latch is formed with a projection 32 engageable beneath a formation 33 on the retainer 1 5. A torsion spring 34 acts between the operating member and the latch to urge the projection 32 into engagement with the retainer and when these parts are engaged with the projection 32 beneath the formation 33, the latch restrains movement of the operating member from its operative position.

If the latch 31 is pivoted about the axis 30 to withdraw the projection 32 from beneath the formation 33, the handle 27 can then be raised to pivot the operating member to its inoperative position. This pivoting moves the face 29 away from the retainer axis 1 6 and the retainer is permitted to move to its open position under thp action of its spring 1 8 either immediately, when there is no ball present in the socket 11, or when any ball present in the socket moves out of the socket. As the retainer moves into its open position, restraining means in the form of a projection 35 on the retainer moves into a position adjacent to a shoulder 36 on the operating member where the projection 35 restrains movement of the operating member to its operative position.Pivoting of the retainer under the action of its spring 1 8 is limited by engagement of the projection 35 with an abutment 37 on the operating member.

When the retainer 1 5 is in its open position, the force derived from the springs 25 and 26 and exerted on the retainer by the operating member 1 9 is directed generally towards the retainer axis 1 6 so that either no torque or no substantial torque about the retainer axis is transmitted to the retainer by the operating member, and there is no tendencyforthe springs 25 and 26 to effect movement of the retainer to its closed position.

When the retainer 1 5 is in its open position, the tip of the latch 31 engages the formation 33. The retainer can be moved to its closed position by the application of pressure to the end portion of the latch 31 which is adjacent to the handle 27. This pressure is transmitted by the latch to the formation 33. As the retainer is moved into its closed position, the operating member 1 9 will tend to move to its operative position.

There is also provided a lock 38 which acts as a second means for restraining movement of the retainer 1 5 from its closed position. The lock extends through an aperture formed in the wall 21, which is remote from the latch 31, to a position in the path of travel of a formation 39 on the retainer which is adjacent to the wall 21. The formation 39 corresponds to the formation 33 which is adjacent to the wall 22. The lock can be withdrawn from the aperture in the wall 21 to permit the retainer to move to its open position.

The lock 38 is preferably a known plug-in lock as referred to in British Specification No.

1,556,525. This form of lock is operated by a removable key. Alternatively, there could be provided a combination lock having a plurality of settable elements which must be set in respective predetermined positions before the lock can be inserted into or removed from the aperture in the wall 21. If two adjacent apertures are provided in the wall 21, there could be used in place of the lock 38 a padlock. The hasp of the padlock would lie in the path of travel of a part of the retainer 1 5 and thereby restrain movement of the retainer to its open position.

The means illustrated in the accompanying drawings for locking the retainer 1 5 against movement from its closed position is simpler and more reliable than is the locking means disclosed in the aforesaid published specification. The formation 39 and that part of the lock which obstructs movement of the retainer are disposed within the body 10 and are not readily accessible.

Thus, these parts cannot easily be damaged sufficiently to renderthe lock ineffective.

Furthermore, the lock does not act on the retainer through any intermediate element. The latch 31 may be omitted, and arrangement of lock herein disclosed still being effective to restrain movement of the retainer from its closed position.

Claims (7)

1. A coupling device of the kind specified having a lock engageable with the retainer to restrain movement of the retainer from its closed position, the lock being operable to release the retainer for movement to its open position.

2. A device according to Claim 1 wherein the body is formed with an aperture into which the lock can be introduced and in which the lock can be rendered a captive of the body.

3. A device according to Claim 1 or Claim 2 wherein there is mounted on the operating member a latch which is engageable with the retainer when the retainer is in its closed position to restrain movement of the operating member from its Operative position.

4. A device according to Claim 3 wherein the latch is mounted on the operating member at one side thereof and is engageable with a first formation on the retainer at a corresponding side of the retainer and wherein the lock is engageable with a second formation on the retainer at a further side of the retainer.

5. A device according to any preceding claim wherein the lock is a key-operated mechanism.

6. A coupling device substantially as herein described with reference to and as shown in the accompanying drawings.

7. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.