GB2160163A - Fifth-wheel trailer coupling - Google Patents

Abstract

A fifth wheel coupler having a coupling mechanism including a wedge (18) arranged to retain a hook member (16) in position to retain a king-pin (22), is characterised by a retaining means for an operating lever (20) which through a lever arm (30) moves the wedge (18); the retaining means (35, 39, 48) being such that the operating lever (20) has to be moved in a direction transverse to the direction in which the lever is moved to disengage the wedge from the hook member; the retaining means being maintained in its retained position by a suitable biassing means (38). The retaining means is preferably in the form of a narrow portion of a slot (35) which cooperates with notches (39, 48) to hold the operating lever in the wedge engaged position and disengaged positions respectively. <IMAGE>

Description

SPECIFICATION Improvements in and relating to a fifth wheel coupler This invention relates to a fifth wheel coupler for coupling a tractor vehicle to a trailer or semitrailer.

A known fifth wheel coupler is disclosed in G.B.

Patent No. 983568 having a coupling mechanism which is operated by a lever connected to the wedge portion of the coupling mechanism. The lever is held in the coupled position by a latch pivotted against the action of a spring. Such a latch arrangement for the lever is relatively complicated in design and prone to unlatching by mistake.

Other 'lock' arrangements for the lever are also known including a clip-hook and chain arrangement which is relatively awkward to use and complicated in design.

A fifth wheel coupler in accordance with the invention comprises a body plate defining generally an entrance slot for a king-pin, a coupling member mounted to the body plate and positioned at the apex of the entrance slot, the coupling member comprising a hook member to engage the king-pin during coupling and a locking wedge to engage and lock the hook member during coupling, an operating lever mounted to the locking wedge and capable of moving the wedge to a disengaged position substantially clear of the entrance slot during uncoupling, and retaining means for the operating lever disengageable by movement of the lever in a direction substantially transverse to that direction in which the lever is moved to disengage the wedge from the hook member, the retaining means being maintained in its retained position(s) by biasing means.

The operating lever of such an arrangement is easy to use, simple in design and construction,and provides secure retainment for the operating lever either in its coupled or uncoupled position.

Preferably, the retainment means comprises at least one notch provided on the operating lever cooperating with a slot provided in the body plate.

The slot in the body plate may be formed with a varied width such that movement of the operating lever in said transverse direction allows the notch subsequently to pass through the wider portion of the slot and be disengaged.

Advantageously, the operating lever is maintained by the biasing means in the narrower portion of the slot. To disengage the notch from the slot, the operating lever is moved in said transverse direction against the action of the biasing means to allow then the notch to pass through the wider portion of the slot.

The retainment means may comprise two notches on the operating lever, one for retaining the lever in the coupled position and one for retaining the lever in the uncoupled position. The lever is accordingly maintained in the narrower portion of the slot both when the lever is in the coupled and uncoupled positions.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an underneath plan view of a coupler in accordance with the invention, Figure 2 is a side view of the coupler of Figure 1, and Figure 3 is a greatly enlarged cross-section of a portion of the coupler of Figure 1 as taken along the line A-A of Figure 1.

The coupler 10 shown in the drawings comprises essentially a body plate 12 having an entrance slot 14 on one side of the inner end of which slot a hook member 16 is pivotally mounted, a locking wedge 18 and operating lever 20 connected to the wedge being provided on the other side of the slot.

The coupler of Figure 1 is shown in the coupled position in which a king-pin 22 lies with its shank surrounded by the hook 16 and with its head, which is of larger diameter than the shank, abutting against a seating 24 on the coupler. The hook is held in the locked or coupled position by the wedge 18 which is in wedging contact with the hook and lies against two stops 26 one on each side of the entrance slot 14. In order that wedging contact may be maintained in spite of wear of the parts, an adjustable stop 28 is provided for the wedge, such that when wear has occurred the stop 28 is adjusted outwardly to allow the wedge to extend further across the plate 12.

The operating lever 16 is formed from two lever arms 30 and 32 pivotted together at the point 34.

The operating lever 16 in Figure 1 is shown in the coupled position held by a spring 36, the lever arm 32 situated in the lower narrower portion of a slot 35 provided in the side extension 37 of the body plate 12.

Retainment means in the form of a first notch 39 is provided on the arm 32, to prevent the operating lever 16 from moving out of its coupled position, as any movement thereof will cause the notch 39 to co-operate with and engage the side wall of the slot 35.

The arm 32 is maintained or 'kept' in the lower portion of the slot 35 by biasing means specifically a spring loaded plunger 38 connected to the underside of the body plate.

To move the operating lever 16 initally into an uncoupled position, the lever arm 32 is lifted upwards against the action of the plunger 38 (see arrow A in Figure 3) and slightly sideways, such that the arm 32 is within the wider upper portion of the slot 35. The notch 39 on the arm 32 will subsequently not engage the side wall of the slot 35, when the operating lever 20 is pulled via the handle 40 outwards (see arrow B in Figure 1) from the side extension 37 against the action of the spring 36.

The operating lever 20 is maintained and "held" in its uncoupled postion by firstly moving the lever arm 32 sideways such that the retainment means in the form of a second notch 48 thereon engages the side wall of the slot 35, and secondly by the action of the plunger 38 against the lever 20 to bias it in the narrower portion of the slot 35.

When the operating lever 20 is moved to its un coupled position, the wedge 18 which is connected at the point 42 to the lever arm 30 is removed from its locking position. This allows movement of the king-pin 22 towards and out of the entrance slot 14 to take place to uncouple the trailer, the king-pin 22 as it moves causing the hook member 16 to be swung on its pivot 43 and due to the action of a spring 44, into an uncoupled position.

On entry of the king-pin 22 during a further coupling operation, the arm 46 of the hook member 16 will be engaged, and the wedge member 18 freed to assume its locking position.

As the pin moves further in engaging the arm 46, the hook member is caused to turn about its pivot 43 into the coupled position shown in Figure 1.

Thereafter the operating lever 20 is unlocked by disengaging the notch 48 on the lever arm 32 from the slot 35 in the side of the plate member, whereafter the spring 36 biases the operating lever 20 and wedge 18 into their coupled positions in which the wedge lies between the arm 50 of the hook member 16 and the pair of stops 26. The tip of the wedge member 18 and arms 46 and 50 are appropriately shaped so that the wedge slides across into locking position without catching on the hook member 16.

The fifth wheel coupling shown is provided with trunnions or brackets generally shown at 52 to support a horizontally disposed axle collar 54 about which the coupler 10 may pivot, the trunnions or brackets 52 being supported on two mounting foots 56, one each side of the coupler 10.

It will be appreciated that coupling can be effected without any manual operation of the parts, apart from the movement of the operating lever 20 to effect uncoupling.

Claims (7)

1. A fifth wheel coupler comprising a body plate defining generally an entrance slot for a kingpin, a coupling member mounted to the body plate and positioned at the apex of the entrance slot, the coupling member comprising a hook member to engage the king-pin during coupling and a locking wedge to engage and lock the hook member during coupling, an operating lever mounted to the locking wedge and capable of moving the wedge to a disengaged position substantially clear of the entrance slot during uncoupling, and retaining means for the operating lever disengageable by movement of the lever in a direction in which the lever is moved to disengage the wedge from the hook member, the retaining means being maintained in its retained position(s), by biassing means.

2. A coupler as claimed in Claim 1 wherein the retaining means comprises a first notch provided on the operating lever co-operating with a slot provided in the body plate.

3. A coupler as claimed in Claim 2 wherein the slot co-operating the operating lever has a narrow portion and a wide portion such that the wide portion allows the lever to pass through the slot whilst the narrow portion co-operates with the first notch in the operating lever to retain the lever in a position so as to lock the wedge in a coupled position.

4. A coupler as claimed in any one of Claims 1 to 3 wherein the retaining means further comprises a second notch provided on the operating lever to lock the lever so as to lock the wedge in an uncoupled position.

5. A coupler as claimed in Claims 3 and 4 wherein the second notch co-operates with the narrow portion of the slot to retain the lever and hold the wedge in the uncoupled position.

6. A coupler as claimed in Claim 3 wherein the biassing means comprises a spring loaded plunger acting on the lever to urge the lever into the narrow portion of the slot.

7. A fifth wheel coupler substantially as described with reference to the accompanying drawings.