GB2079704A

GB2079704A - A coupling pin

Info

Publication number: GB2079704A
Application number: GB81117609A
Authority: GB
Original assignee: NEWNHAM THOMAS OLIVER
Current assignee: NEWNHAM THOMAS OLIVER
Priority date: 1980-06-18
Filing date: 1981-06-09
Publication date: 1982-01-27
Also published as: AU7331381A; FR2485122A1; GB2079704B; FR2485122B3; DE3123924A1

Abstract

A coupling pin comprised of a stem portion 10 with an enlarged head portion 11 at one end thereof. The other end 12 of the stem is bifurcated by a slot 14 extending inwardly therefrom. A movable element 16 is pivotally located within said slot 14 and spring bias means 20 are provided within the slot 14 to urge the movable element 16 to a latching position where a latching portion 22 thereof projects from the slot 14 at a point inward of the end 12 of the stem 10 from which the slot extends. Preferably the stem 10 is of a circular cross section with the slot 14 extending diametrically along the stem to terminate in an inner inclined wall 15. The movable element 16 preferably has an inclined face 18 at its free end which engages in a face to face contact with the inclined wall 15 when the movable element 16 is in the latching position. The coupling pin can be utilised with a D-shackle used in attaching a safety chain between a trailer and a towing vehicle. <IMAGE>

Description

SPECIFICATION A coupling pin This invention relates to a coupling pin.

Coupling pins are in common usage in many applications, and their main function is to provide a means of coupling one element to another. This can be carried out either by one element being attached to the coupling pin with the coupling pin then being located with the second element. Alternatively, the coupling pin can be used in a situation such as with a D-shackle where the shackle is attached to an element and a second element is attached to the shackle by being captured therein by the coupling pin. D-shackles are in common usage in many different applications, one which is very common being the attachment of a safety chain from a trailed vehicle such as a trailer or caravan to the tow-bar of the towing vehicle.

In such situations, it is quite common for the coupling pins to be subjected to insertion and removal at regular intervals. Normally the coupling pin is inserted or removed by rotation so as to unscrew a threaded stem portion from a threaded opening. This can be quite time consuming and tedious especially if the pin is regularly being removed or inserted. In addition, the coupling can become unsafe due to the coupling pin coming unthreaded during use. To ensure this cannot happen, the threaded stem portion must be locked in the coupling.

The present invention has as its object to provide a coupling pin which has such a construction that it is safe and can be quickly removed or inserted during use thereof.

In one broad aspect the invention consists of a coupling pin comprising a stem portion having at one end thereof an enlarged head portion, the other end of the stem being bifurcated by a slot extending inwardly from said other end, a moveable element pivotally located within said slot and spring bias means located within said slot to urge the moveable element to a latching position where a latching portion thereof projects from said slot at a point inward of the said other end of said stem.

To more fully describe the invention, reference will be made to the accompanying drawings in which: Figure lisa sectional side view of the coupling pin according to the invention, Figure 2 is a top plan view, Figure 3 is a partial side view similar two Figure 1 but showing a modified form of the coupling pin, and Figure 4 is a further partial side view but showing a second modified form of the coupling pin.

The stem 10 is of circular cross-section and is provided at one end with an enlarged head 11. This head can be of any particular size and configuration as may be necessary to suit the purpose in which the coupling pin will be engaged. For example, the head portion 11 can be a thin flat member which can be readily gripped by the fingers of the person engaging or withdrawing the pin. Alternatively, the head portion 11 can be of circular cross section with a diameter greaterthan that of stem 10.

Extending inwardly from the free end 12 of the stem 10 a diametric longitudinally extending slot 14 is provided so that the end of the stem is bifurcated.

This slot 14 extends from the extreme end 12 of the stem 10 to terminate at an inner end formed by an inclined wall 15 (see Figure 1). A movable element 16 is located within slot 14 and is pivotally mounted about a pivot pin or axle 17 located toward the outer end of slot 14. The free end 18 of movable element 16 is so shaped that when it is in the position shown in Figure 1 it engages against inclined wall 15.

Movable element 16 is provided with a rebated portion 19 in which the free end of a spring member 20 such as a length of spring steel can locate. The spring member 20 is inserted in a recess 21 which extends inwardly from inclined wall 15. This springsteel wire member 20 thus normally urges movable element 16 upward so that surface 18 engages against inclined wall 15. Portion 22 of movable element 16 which projects from the peripheral surface of stem 10 thus provides a latching portion as will hereinafter be described.

In an alternative form, as shown in Figure 3, the free end 18 of movable element 16 is shaped in the length of latching portion 22 so as to have a portion 18' which is substantially normal to the longitudinal axis of stem 10.

The coupling pin can be readily inserted into the opposed openings of say the legs of a D-shackle by inserting end 12 and pushing the stem 10 through the opening. This results in movable element 16 being pushed inwardly against the spring bias of spring member 20 such thatthe latching portion 22 locates within the confines of slot 14. This movement is possible as surface of free end 18 of movable element 16 is so inclined that it moves away from its engagement with inclined wall 15. Once the movable element has moved through the opening it can revert to the position shown in Figure 1. To remove the coupling pin it is merely revolved slightly and pulled as the action of revolving and pulling causes the pawl to drop.The projecting portion of wall 18 of latching portion 22 to engage with the edge of the opening is pushed down against the spring bias of spring member 20 to locate fully within the slot 14.

With the arrangement shown in Figure 3, the movable element 16 must be depressed into the confines of slot 14 by the user. This action is necessary as the vertically extending portion 18' locks against the edge of the opening 18 thus preventing the stem being withdrawn from the opening.

The coupling pin according to the present invention is of a simple construction though effective in operation. It is extremely simple to use either in the form shown in Figure 1 where it can be readily removed by the user pulling the head portion 11 or in the form shown in Figure 3 where the user must first depress the movable element 16 into the slot 14 before pulling on head portion 11. The coupling pin is of particular use with D-shackles where the stem must pass through aligned openings with the legs of the shackle.

The coupling pin is open to modification. For example, in Figure 4the coupling pin includes a locking pawl 25 which is located within slot 14 at the extreme end of stem 10. A hollowed or recessed portion 26 at the end of stem 10 permits ready access to the pawl 25. This pawl is used to lock the movable element 16 in position within slot 14 as shown in Figure 4. This locking is achieved by the top portion 27 of pawl 25 engaging under a lip 28 at the extreme end of movable element 16. The rebated portion 29 of pawl 25 engages with lip 28 when the movable element 16 is in the position where latching portion 22 projects from the slot 14. To release the pawl 25 the lower portion 30 is pushed inwardly so as to move the top portion 27 from beneath lip 28.

Claims

1. A coupling pin comprising a stem portion (10) having at one end thereof an enlarged had portion (11), the other end (12) of the stem being bifurcated bya slot (14) extending inwardly from said end (12), a movable element (16) pivotally located within said slot and spring bias means (20) located within said slot (14) to urge the movable element (16)to a latching position where a latching portion (22) thereof projects from said slot (14) at a point inward of the said other end (12) of said stem (10).

2. A coupling pin as claimed in claim 1 wherein said stem (10) is of circular cross-section and the slot (14) extends diametrically along said stem to terminate in an inner inclined wall (15).

3. A coupling pin as claimed in claim 2 wherein the movable element (16) is pivoted at a point at or adjacent said other end (12) of the stem, the free end of the movable element (16) being provided with a surface (18) which engages in face to face contact with said inclined wall (15), when said movable element is in said latching position, but moves away from said inclined wall (15) when said movable element is pivoted against the spring bias (20) to be located fully within said slot (14).

4. A coupling pin as claimed in claim 3 wherein said spring bias means comprises a spring element (20) extending from said inclined wall (15) to engage in locating means (19) in said movable element (16).

5. A coupling pin as claimed in claim 4 wherein said spring element is a spring steel length (20) fixedly located by one end in a recess (21) in said inclined wall (15) and engaged at its other end in a rebated portion (19) of said movable element (16).

6. A coupling pin as claimed in claim 4 or 5 wherein the latching portion (22) of the movable element includes an edge surface which inclines away from the enlarged head portion (11) when the movable element (16) is in the latching position.

7. A coupling pin as claimed in claim 4 or 5 wherein the latching portion (22) of the movable element includes an edge surface (18') which is substantially at right angles to the longitudinal axis of said stem (10) when the movable element (16) is in the latching position.

8. A coupling pin as claimed in claim 4 or 5 wherein a locking pawl (27) is located in the slot (14) at the other end (12) of said stem (10), said pawl being engagable in a recess (28) in the outer end of said movable element (16) to lock the movable element in a position where the latching portion (22) thereof is located within the confines of said slot.

9. A coupling pin substantially as herein described with reference to the accompanying drawings.