GB2124288A - Releasable clamp - Google Patents

Abstract

A clamp, for securing the end of a rope or chain to a pin protruding from a work surface, comprises an elongate body (11) and a collar (12) which is a close sliding fit over the body; one end of the clamp body is fixed in use to the rope-end or chain-end; the other end of the clamp body (12) comprises two side-by-side pawls (16, 17) which can move apart and together again and which, when brought together, embrace the pin (13); and the collar when fitted over the body prevents the pawls from moving so far apart as to lose their purchase on the pin. The pin (13) spans a boss into (14) which the collar (12) fits closely as it comes down over the pawls, with the wall of the collar being cut away to clear the pin to allow the collar to come down over the pawls, and with the boss being fixed in use to the work surface (15) to provide a secure anchorage. The collar and clamp body interengage to resist the collar sliding off the body when the collar is in an operative mode, and the pawls are provided with several pin-engaging positions. <IMAGE>

Description

SPECIFICATION Releasable clamp The invention relates to releasable clamps.

The invention is particularly concerned with clamps for securing the end of a rope or a chain (or other elongate fastening band-element) to a work surface. Ropes, chains and the like are commonly used for holding down tarpaulins over loads on lorries, and for fastening down wheelchairs to the floor of an ambulance or other passenger transport. Conventionally the ropes or chains are knotted or shackled to an eye in the work surface, but this has drawbacks: it requires a certain amount of strength and skill, and the rope or chain can work loose when placed under repeated tension.

The invention is based on the concept of a clamp which embraces, releasably, a pin protruding from the work surface. The pin provides a secure location for the clamp, which is itself fixed to the rope-end or chain-end, and the clamp incorporates a means of keeping it embraced around the pin until the clamp is ready for release.

According to the invention a clamp, for securing the end of a rope or chain to a pin protruding from a work surface, comprises an elongate body and a collar which is a close sliding fit over the body; one end of the clamp body is fixed in use to the rope-end or chain-end; the other end of the clamp body comprises two sideby-side pawls which can move apart and together again and which, when brought together, embrace the pin; and the collar when fitted over the body prevents the pawls from moving so far apart as to lose their purchase on the pin.

The pin may span a boss into which the collar fits closely as it comes down over the pawls, with the wall of the collar being cut away to clear the pin to allow the collar to come down over the pawls, and with the boss being fixed in use to the work surface to provide a secure anchorage.

The collar and clamp body may inter-engage to resist the collar sliding off the body when the collar is in an operative mode. For example there may be a screw-threaded inter-engagement, or other twist-and-iock connection, between the two.

The pawls are preferably biased into their sideby-side pin-embracing position. They may for example be biased by gravity when the pin is horizontal and the body and collar upright in their pin-embracing attitude. They may alternatively or additionally be spring-biased together for example by torsion springs in the pawl pivots (in a case where the movement of the pawls is a pivotal movement).

The collar and body may conveniently be circular-cylindrical.

The pawls may be provided with several pinengaging positions.

One clamp embodying the invention is illustrated in the accompanying drawings. It is only one example of forms which the invention might take, but it is the best mode known to the applicant of putting the invention into practice. In the drawings.: Figure 1 shows the clamp and its co-operating pin and pin-holding boss in cross-section; Figure 2 is a view simliar to that of Figure 1 but showing the clamp in its pin-embracing position and the collar in its operative mode; Figure 3 is a view similar to that of Figure 2 but taken at right angles to it; and Figure 4 illustrates a modification to the clamp of Figures 1 to 3.

The clamp illustrated comprises an elongate circular-cylindrical steel body referenced 11 and a similarly elongate circular-cylindrical steel collar 12 both cooperating with a hardened steel solid circular-cylindrical pin 13.

The pin 13 spans the diameter of a "top-hat" boss 14 which is itself circular-cylindrical, and which is flanged and open at one end whilst being closed off at the other end.

In use, as Figure 2 shows, the boss 14 is secured firmly to a work surface 1 5 by screwing or rivetting or other appropriate means. For example the flange of the boss may be drilled and countersunk to take screws securing the boss to the work surface 15.

The surface 1 5 may be the substantially flat level floor of an ambulance vehicle in the case where the clamps are to be used to rope wheelchairs down to the floor of the ambulance for transport.

Pawls 16, 1 7 are each individually pivotted at one end of the circular-cylindrical solid body 11.

Each pawl incorporates a V notch in its side surface facing the other pawl. The two notches are so positioned that when the pawls are brought together into side-by-side relationship the notches define a square cutout which embraces the pin 13.

When the pawls are in side-by-side relationship as illustrated in Figure 2, the collar 12 slides down over them and prevents them from moving apart to any appreciable extent. Thus, the two pawls when brought together are so shaped thay they define a cylindrical extension of the body 11.

The end of the body 11 opposite the pawl carrying end is fixed, in use, to the end of a rope or chain or other fastening band-element. The means of fixing are not illustrated and can readily be selected from known alternatives by the skilled addressee of this specification. For example, the body-end might extend into a hollowed-out section which can be crimped onto a rope-end or cable-end; or alternatively an eye can be cast into the body-end or constituted by a hole drilled through it to allow a cable or chain to be shackled to the body-end.

Initially, as shown in Figure 1, the collar 12 is held away from the pawls 16, 17 in an inoperative position to allow the pawls to embrace the pin 13. Once this has been done, the collar 12 is manually slid down into its Figure 2 and Figure 3 position to retain the pawls in their pin-embracing state.

As Figure 3 shows, diametrically opposite open-ended slots are cut into the wall of the collar 12 to allow the collar to come down round the pin 13.

The collar 12 could be knurled or otherwise patterned around its outside surface to assist manual grip. The knurling or other patterning could occupy only a top portion of the collar surface.

The inside surface of the collar could be tapered in such a way that any tendency of the pawls 16, 1 7 to move apart, once the collar 12 is in its operative mode, will act to move the collar more firmly onto the pawls. In the illustrated embodiment, the collar could taper inside from top to bottom so that any tendency of the pawls to open simply pushes the collar more firmly down against the closed end of the boss 14.

Other modifications within the scope of the invention will become apparent to the skilled addressee.

Claims (Filed on 20 June 1983) 1. A clamp, for securing the end of a rope or chain to a pin protruding from a work surface, and comprising an elongate body and a collar which is a close sliding fit over the body; one end of the clamp body being fixed in use to the rope-end or chain-end; the other end of the clamp body comprising two side-by-side pawls which can move apart and together gain and which, when brought together, embrace the pin; and the collar being so sized and shaped that when fitted over the body it prevents the pawls from moving so far apart as to lose their purchase on the pin.

2. A clamp according to Claim 1 and in which the pin spans a boss into which the collar fits closely as it comes down over the pawls, the wall of the collar being cut away to clear the pin to allow the collar to come down over the pawls, and the boss being fixed in use to the work surface to provide a secure anchorage.

3. A clamp according to Claim 1 or Claim 2 and in which the collar and clamp body inter-engage to resist the collar sliding off the body when the collar is in an operative mode.

4. A clamp according to Claim 3 and in which there is a twist-and-lock connection between the collar and the clamp body.

5. A clamp according to any of the preceding claims and in which the pawls are biased into their side-by-side pin-embracing position by gravity when the pin is horizontal and the body and collar upright in their pin-embracing attitude.

6. A clamp according to any of the preceding claims and in which the pawls are provided with several pin-engaging positions.

7. A clamp substantially as described herein with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. and Figure 3 position to retain the pawls in their pin-embracing state. As Figure 3 shows, diametrically opposite open-ended slots are cut into the wall of the collar 12 to allow the collar to come down round the pin 13. The collar 12 could be knurled or otherwise patterned around its outside surface to assist manual grip. The knurling or other patterning could occupy only a top portion of the collar surface. The inside surface of the collar could be tapered in such a way that any tendency of the pawls 16, 1 7 to move apart, once the collar 12 is in its operative mode, will act to move the collar more firmly onto the pawls. In the illustrated embodiment, the collar could taper inside from top to bottom so that any tendency of the pawls to open simply pushes the collar more firmly down against the closed end of the boss 14. Other modifications within the scope of the invention will become apparent to the skilled addressee. Claims (Filed on 20 June 1983)

1. A clamp, for securing the end of a rope or chain to a pin protruding from a work surface, and comprising an elongate body and a collar which is a close sliding fit over the body; one end of the clamp body being fixed in use to the rope-end or chain-end; the other end of the clamp body comprising two side-by-side pawls which can move apart and together gain and which, when brought together, embrace the pin; and the collar being so sized and shaped that when fitted over the body it prevents the pawls from moving so far apart as to lose their purchase on the pin.

2. A clamp according to Claim 1 and in which the pin spans a boss into which the collar fits closely as it comes down over the pawls, the wall of the collar being cut away to clear the pin to allow the collar to come down over the pawls, and the boss being fixed in use to the work surface to provide a secure anchorage.

3. A clamp according to Claim 1 or Claim 2 and in which the collar and clamp body inter-engage to resist the collar sliding off the body when the collar is in an operative mode.

4. A clamp according to Claim 3 and in which there is a twist-and-lock connection between the collar and the clamp body.

5. A clamp according to any of the preceding claims and in which the pawls are biased into their side-by-side pin-embracing position by gravity when the pin is horizontal and the body and collar upright in their pin-embracing attitude.

6. A clamp according to any of the preceding claims and in which the pawls are provided with several pin-engaging positions.

7. A clamp substantially as described herein with reference to and as illustrated in the accompanying drawings.