GB2269848A

GB2269848A - Releasable connnector

Info

Publication number: GB2269848A
Application number: GB9216909A
Authority: GB
Inventors: Barry John James
Original assignee: Gang Nail Systems Ltd
Current assignee: Aldershot GNS Ltd
Priority date: 1992-08-10
Filing date: 1992-08-10
Publication date: 1994-02-23
Also published as: GB9216909D0

Abstract

A releasable connector eg between two elements (12, 14) comprising an abutting member (16) arranged to abut against one element (12) and a projecting member (20) carrying at least one projection (22) for interengagement with cammed groove means (34) on the other element (14). The projecting member (20) is slidably mounted with respect to the abutting member (16) and is biased into a retracted position by means of resilient means (32). Rotation of the projecting member (20) when engaged with the cammed groove means (34) forces the member into an extended position against the biasing of the resilient means (32). This provides a connector which is easy and quick to use, versatile and cannot be overtightened. It is suitable for connecting two members together as shown, e.g. a frame and a platen for use in a jig for manufacturing trusses, or for clamping onto a single member, e.g. to form a stop located on a frame. <IMAGE>

Description

RELEASABLE CONNECTOR The invention relates to a releasable connector.

Particularly, but not exclusively, the invention relates to a releasable connector for connecting a frame to a platen of a press head forming part of an automatic jig for manufacturing trusses and for forming a releasable stop for location on such a frame.

Many releasable connecting devices are well known.

However, the majority of connecting devices are formed such that, although it is imperative that the device is well tightened, overtightening can be detrimental and in some cases catastrophic. A typical example is a nut and bolt wherein the nut must be sufficiently tightened to avoid a loose connection being formed. However, overtightening of the nut on the bolt would result in damaging of the screw thread. Many other connectors are known and have the same or similar disadvantages.

It is an object of the invention to provide a connecting device for connecting a first member to a second member which can be easily and quickly tightened to a sufficient degree to ensure a firm connection between the members and which cannot be overtightened.

Releasable stops for fixing to various articles are also known. However, these stops are often either too easily knocked out of position or are awkward and inconvenient to attach, in particular to relocate. It is therefore a further object of the invention to provide a releasable connector which can be used as a stop and which can be reliably and firmly connected to an article and which is quick and easy to relocate.

The invention provides a releasable connector comprising an abutting member arranged to abut against an element to which the connector is to be connected and a projecting member extending away from the abutting member, the projecting member carrying at least one radially extending projection for interengagement with cammed groove means and being rotatable about an axis with respect to the cammed groove means, wherein the projecting member is slidably mounted with respect to the abutting member and is biased into a retracted position by means of resilient means acting between the abutting member and the projecting member such that, in use and on interconnection of the at least one projection carried by the projecting member and the cammed groove means, the projecting member is forced into an extended position against the biasing of the resilient means.

The connector of the invention is easy and quick to use since it cannot be overtightened. It is also versatile and has many possible uses.

Advantageous features of the intention are set out in the subclaims.

As indicated in the subclaims, the connector can be used to connect a first member to a second member.

Alternatively, the connector can be used in the manner of a stop and can be connected to a single member. The connector is ideally suited for use to connect frame members for supporting timber members to the platens of press heads forming part of an automatic jig for manufacturing trusses, and for forming stops on those frame members.

Embodiments of the invention will now be described with reference to the accompanying drawings, wherein; Figure 1 is a sectional view of a connector according to a first embodiment of the invention; Figure 2a is a sectional view of the connector of Figure 1 during the initial stages of use; Figure 2b is a sectional view of the connector of Figure 1 fully connected to a second member; Figure 3 is a sectional view of a connector according to a second embodiment of the invention; and Figure 4 is a sectional view of a connector according to a third embodiment of the invention.

Figure 1 shows a connecting device 10 suitable for connecting a first member 12 to a second member 14. The connector 10 comprises a housing 16 in which is slidably located a cylindrical member 18 connected to a coaxial projecting member 20. The projecting member 20 protrudes from a circular aperture in the housing 16 and carries diametrically opposed bayonet catches 22. The number of bayonet catches is not limited to two and could be varied. The catches are ideally equispaced about the circumference of the projecting member 20.

The cylindrical member 18 abuts against one end of a handle member 24 which prevents the projecting member 20 from being retracted further into the housing 16. The cylindrical member 18 incorporates a non-cylindrical protrusion 26 which engages with a corresponding aperture in the handle member 24 such that the cylindrical member 18 and protruding member 20 are rotatable with and by means of the handle 24. The handle 24 protrudes through an opening in the housing 16 to allow the handle 24, cylindrical member 18 and projecting member 20 to rotate with respect to the housing 16.

The handle member 24 abuts against a disc shaped member 28 which is held in place with respect to the housing by means of a split ring 30. A disc spring 32 acts between the end of the housing 16 remote from the split ring 30 and the adjacent face of the cylindrical member 18 so as to bias the projecting member 20 into a retracted position, i.e. towards the right as shown in Figure 1. Alternative suitable biasing means could equally be used.

The first member 12 is formed by a frame for attachment to a platen which forms the second member 14. -In the platen 14, a pair of cammed grooves 34 are located in an aperture 36, the function of which will be described below.

Figures 2a and 2b show diagramatically the operation of the connector 10. When the connector 10 is to be used to connect the frame 12 to the platen 14, the bayonet catches 22 are aligned with the apertures 34 in the platen 14. The projecting member 20 is then introduced into the aperture 36 in the platen 14 such that the frame 12 is clamped between the housing 16 and the platen 14. The bayonet catches 22 are at this stage located at the beginning of the cammed portions of the grooves 34.

The handle 24 is then rotated through approximately 90 as shown in Figure 2b. The bayonet catches 22 are rotated with the handle 24 and are therefore forced to pass along the cammed portions of the grooves 34. The movement of the bayonet catches 22 along the cammed grooves 34 thus draws the projecting member 20 further into the aperture 36 and the cylindrical member 18 towards the platen 14 against the bias of the spring 32. The movement of the cylindrical member 18 has been exaggerated in Figure 2b; in fact, the movement is slight and is compensated by a slight axial movement between the non-circular protrusion 26 and the handle member 24. The engagement between the protrusion 26 and the handle member 24 is retained.

Clearly, the connector described above is releasable from the second member 14 merely by rotation of the handle 24 in the opposite direction to that described for connection and retraction of the projecting member 20 and bayonet catches 22 from the grooves 34 and aperture 36 of the second member 14. The cylindrical member 18 then returns to the position shown in Figures 1 and 2a.

The construction described above allows an extremely high clamping pressure to be applied to the members to be connected without causing any damage to the connector 10 or either member 12, 14. The spring 32 or other biasing means ensures that overtightening does not occur and therefore has no detrimental effect.

A further advantageous feature of the connector is that the first member 12 can, if desired, be permanently mounted on the projecting member 20 to avoid the possibility of the member 12 becoming separated from the connector 10. This is achieved by the provision of a suitably sized aperture in the first member 12 which is just larger in diameter than the projecting member 20 but smaller in diameter than the bayonet catches 22.

The first member 12 is thus loosely mounted on the projecting member 20 in a non-releasable manner.

Equally, it is possible for the first member 12 to be releasably mounted on the projecting member 20 by providing an aperture having a diameter greater than that of the bayonet catches 22 or by providing an aperture having a diameter as described above, i. e.

having a diameter just larger than that of the projecting member 20 but smaller than the bayonet catches, and also providing apertures corresponding to the bayonet catches and through which the bayonet catches can pass.

The connector described above is particularly useful for connecting frames to the platen of a press head in an automatic jig for manufacturing trusses. The frames support timber members for forming a truss and create a gap between the platen and the timber members so that connector plates can be positioned therebetween. It is imperative in such a situation that each frame is securely connected to the platen but is easily releasable if so desired, for example if two press heads are to be used close together. The connectors described above are permanently fixed to suitable frames mounted on the projecting members 20 and retained thereon by means of the bayonet catches 22.However, it would be possible to arrange for suitable apertures to be provided in the frame members such that the projecting members 20 and bayonet catches could be passed through these suitable apertures in the frames before being connected to the platen 14. Such an arrangement would allow different combinations of frames and connectors to be utilised as desired. However, arranging for the frames 12 to be non-releasably mounted on the protruding members 20 of the connectors 10 ensures that the frames and connectors do not become disconnected.

The frames are connected to the platen by introducing the projecting members of the connectors into the apertures in the platen so that the frames carried by the projecting members are held between the platen and the housing. The handles of the connectors are then rotated through 90 to force the bayonet catches along the cammed grooves, thus clamping the frames in position. Ideally, each frame is carried by two connectors, one at each end, both connectors being non-releasably mounted on the projecting members, and frames are attached to each of three sides of the platen.

Figure 3 shows a alternative embodiment of the invention wherein the connector 10a is used as a stop and is connected to a single member 40. The single member 40 is preferably the upper arm of a frame for a platen as described above. The connector 10a is virtually identical to the connector 10 described in connection with Figures 1 and 2 and like parts have been allocated like reference numerals with the addition of the letter "a".

The projecting member 20a of the connector 10a shown in Figure 3 is slightly longer than the projecting member 20 of the connector 10 shown in Figure 1. This allows the bayonet catches 22a to be positioned slightly further from the free end of the projecting member 20a than was previously described. The projecting member 20a carries at its free end a clamping member 42 which is non-circular in shape, preferably rectangular. The clamping member 42 has an aperture 36a through which the projecting member 20a passes and cammed grooves 34a in which are located the bayonet catches 22a mounted on the projecting member 20a. The clamping member 42 is rotatable about the projecting member 20a such that, on rotation of the projecting member 20a with respect to the clamping member 42, the bayonet catches 22a travel along the cammed grooves 34a.This is achieved by rotation of the handle member 24a. When a single member 40 is interposed between the housing 16a and the clamping member 42, the camming action of the grooves 34a and bayonet catches 22a result in a clamping force being applied to the single member 40 between the housing 16a and the clamping member 42 to clamp the connector 10a onto the single member 40.

When the connector 10a is used to form a stop on a frame 40 connected to the platen of a press head, the frame 40 is provided with a slot along which the connector 10a is slidable to the desired position.

Keyways are provided at either end of the slot through which the clamping member 42 can pass to introduce the connector 10a to the slot. Preferably, a slot and corresponding keyway is provided in each frame connected to any particular platen.

The clamping member 42 is non-circular in shape to assist in the clamping action being achieved. Ideally, the frame to which the connector is clamped comprises a portion 44 extending at right angles to the portion 40 on which the connector is located. If the clamping portion were circular in shape, rotation of the handle member 24a would result in rotation of the clamping member 42 with the projecting portion 22a and no clamping would occur. The clamping member 42 would then need to be restrained from rotating which adds to the complication of the operation of the clamp. This is undesirable, although possible. A non-circular clamping member 42, however, can be designed to abut against the portion 44 of the frame 40 after only a limited amount of rotation and, thereafter, be held in that position with respect to the frame despite continued rotation of the handle.The clamping action is thereby achieved.

The clamping member 42 is preferably rectangular which ensures that the maximum rotation of the handle before clamping commences is less than 90*. It also enables the operator to choose one of four positions in which the handle will remain after clamping has been achieved since there are four possible positions of the handle at which clamping can commence; i. e. one position is associated with each face of the clamping member.

The final position of the handle will depend upon the circumstances involved. The shape of the clamping member 42 can be varied as desired to give as many possible final positions of the handle as necessary. For example, a hexagonal clamping member will give six possible final positions of the handle. The number of faces can be altered as desired provided that there is at least one projection provided for abutment with the frame portion 44 or other suitable abutment means.

Figure 4 shows an alternative embodiment of the connector shown in Figure 3. In this embodiment, the connector comprises an abutment member 50 in the form of a collar through which passes the projecting member 20b. The projecting member 20b incorporates a head 21b at the lower end thereof and a spring 32b is arranged to act between the collar 50 and the head 21b, biasing the two elements away from one another.

The projecting member 20b carries diametrically opposed bayonet catches 22b and also a clamping member 42b which incorporates cammed grooves 34b on its surface facing away from the head 21b. The clamping member 42b takes the form of a washer with a projection 52 arranged to abut the outer edge of the member 40 to which the connector is to be connected. The abutment of the projection 52 against the member 40 prevents the clamping member from rotating relative to the member 40.

Rotation of a handle member 24b attached to the projecting member at the end thereof remote from the head-21b, causes the bayonet catches 22b to rotate with respect to the cammed grooves 34b. The projecting member is then forced into an extended position wherein the head 21b is moved closer to the abutment member against the biasing of the spring 32b. The clamping action is thereby achieved.

The embodiments described above are purely illustrative and should not be regarded as limitative.

For example, the connector could also be adapted to support other devices used in the manufacture of trusses so that these other devices are releasably attachable to the frame of a press head at different locations thereon. Various alternative features could be added without departing from the scope of the invention. For example; the handle could be arrange to rotate about an axis perpendicular to the axis of rotation of the projecting member if convenient and desirable. This could be achieved by any suitable means, for example, bevel gearing. Also, it is not necessary to limit the angle of rotation of the handle with respect to the housing and an angle greater or less than 90 could be allowed. The handle member need not be manufactured as a single piece; indeed, part of the handle could be removable to reduce the overall volume of the connector as a whole. The removable portion of the handle could be arranged to connect to different connectors for convenience. Alternatively, the housing could be arranged to rotate with the handle and the projecting member. Other variations and alternatives will be apparent to one skilled in the art.

Claims

1. A releasable connector comprising an abutting member arranged to abut against an element to which the connector is to be connected and a projecting member extending away from the abutting member, the projecting member carrying at least one radially extending projection for interengagement with cammed groove means and being rotatable about an axis with respect to the cammed groove means, wherein the projecting member is slidably mounted with respect to the abutting member and is biased into a retracted position by means of resilient means acting between the abutting member and the projecting member such that, in use and on interconnection of the at least one projection carried by the projecting member and the cammed groove means and relative rotation therebetween, the projecting member is forced into an extended position against the biasing of the resilient means.

2. A connector as claimed in claim 1, wherein the projecting member carries at least two projections equispaced about the axis.

3. A connector as claimed in claim 2, wherein the projecting member carries two diametrically opposed projections.

4. A connector as claimed in any one of claims 1 to 3, wherein the resilient means comprise a steel disc spring.

5. A connector as claimed in any one of the preceding claims, wherein the projecting member is rotatable about the axis by means of a handle.

6. A connector as claimed in any one of the preceding claims, wherein the abutting member comprises a housing containing the resilient means.

7. A connector as claimed in claims 5 and 6, wherein the projecting member comprises a cylindrical member slidably movable in a bore within the housing, the handle being connected to the cylindrical member to facilitate rotation of the projecting member.

8. A connector as claimed in claim 5, wherein the handle is connected to the projecting member at the end thereof remote from the resilient means.

9. A connector as claimed in claim 5, 7 or 8, wherein the axis about which the handle is rotated in order to rotate the projecting member is the same axis about which the projecting member rotates.

10. A connector as claimed in claim 5, 7 or 8, wherein the axis about which the handle is rotated in order to rotate the projecting member is perpendicular to the axis about which the projecting member rotates.

11. A connector as claimed in any one of claims 5 and 7 to 10, wherein, in use, the handle is rotatable through a maximum angle of 90'.

12. A connector as claimed in any one of the preceding claims, wherein the connector is adapted to connect a first member to a second member, the cammed groove means being located on or in the second member.

13. A connector as claimed in claim 12, wherein the projecting member is arranged to carry the first member during interconnection of the at least one projection with the cammed groove means.

14. A connector as claimed in claim 13, wherein the first member is permanently and non-releasably carried by the projecting member.

15. A connector as claimed in any one of claims 12 to 14, wherein the first member is a frame for supporting timbers during truss manufacture and the second member is the platen of a press head forming part of an automatic jig for manufacturing trusses to which the frame is to be connected.

16. A connector as claimed in any one of claims 1 to 11, wherein the connector is adapted to be connected to a single member and held firmly in place in relation thereto.

17. A connector as claimed in claim 16, wherein the projecting member also carries, in the region of the at least one projection, a clamping member freely rotatable about the projecting member and non-releasably mounted thereon, the clamping member incorporating the cammed groove means located such that relative rotation of the projecting member and the clamping member results in the projecting member being forced into the extended position.

18. A connector as claimed in claim 17, wherein, on relative rotation of the projecting member and the clamping member, the single member is located between the clamping member and the abutting member.

19. A connector as claimed in claim 17 or 18, wherein the clamping member is non-circular in shape.

20. A connected as claimed in claim 19, wherein the clamping member is rectangular in shape.

21. A connector as claimed in any one of claims 16 to 20, wherein the connector forms a stop and the single member is a frame attached to the platen of an automatic jig for manufacturing trusses.

22. A connector as claimed in any one of claims 16 to 21, wherein the connector forms a mounting base for supporting other devices, the housing being adapted to releasably mount said other devices thereon.

23. A releasable connector substantially as hereinbefore described with reference to either of the embodiments shown in the accompanying drawings.