GB2239504A

GB2239504A - Strap-tensioning buckle

Info

Publication number: GB2239504A
Application number: GB9024426A
Authority: GB
Inventors: Adrian Clarke; Richard Howes
Original assignee: EXPROCAD SERVICES Ltd
Current assignee: EXPROCAD SERVICES Ltd
Priority date: 1989-11-10
Filing date: 1990-11-09
Publication date: 1991-07-03
Anticipated expiration: 2010-11-09
Also published as: GB2239504B; GB9024426D0; GB8925451D0

Abstract

A fastener comprising a lover pivotally mounted on a frame with a pair of side walls incorporating a latch to hold the lover temporarily in its locking position; characterised by the feature that the latch comprises an extension of the lever and/ or the frame and is allowed its latching action by virtue of the inherent torsional resilience of that portion of material which demarcates the latch region from the remainder. <IMAGE>

Description

FASTNER Fleld of the Invention The invention relates to fasteners comprising a lever pivotally mounted on a frame having a pair of side walls. The lever is movable between a release position in which the lever extends at an angle to the frame and a locking position in which the lever is disposed substantially flush with frame in between the side walls of the frame.

Such a fastener will be referred to as a fastener of the kind specified.

An example of a fastener of the kind specified is the buckle showed in United Kingdom patent specification No 2 167 510.

Further fasteners of the kind specified are shown in the present applicants previous United Kingdom patent applications Nos GB 2 227 801A and GB 2 226 377A Summary of the Invention According to the invention, there is provided a fastener of the kind specified incorporating a latch to hold the lever temporarily in its locking position; characterised bv the feature that the latch comprises an extension of the lever and/or the frame and is allowed its latching action by virtue of the inherent torsional resilience of that portion of material which demarcates the latch region from the remainder.

The latch is normally part of the lever. The torsional resilience is normally provided by a torsion bar which may be 'L'-shaped in cross section.

The pivot mounting the lever on the frame normally consists of twin shafts each serving to mount one respective side region of the lever and having both centres about a common pivot axis.

One or both pivot shafts is or are moulded as an ultimately integral part of the lever. These are preferably moulded as an integral part of the frame or the lever. Alternatively, the pivot shaft could be incorporated at a later stage in the manufacture of the buckle, for example by inserting it and welding it into place as described in specification Nos GB 2 227 801A and GB 2 226 377A A portion of the frame, lying in a plane generally at right angles to the planes containing the frame side walls, is bored or otherwise adapted for securement to a surface - for example, a lorry side curtain - which is to carry the frame in use. The portion is preferably a channel-section portion with a wall running generally across the run of the frame side walls.

The stop means limit the amount of opening (release) movement of the lever. The stop means preferably exhibits a multipleprotuberance construction.

Brief Descrintion of the Drawings The invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a plan view of a frame of a fastener according to the invention; Figure 2 is a sectional view along line A - A of Figure 1; Figure 3 is an end view of the fastener; Figure 4 is a perspective view of the complete fastener; Figure 5 is a perspective view of a modified version of a fastener according to the invention in an open position.

Ilescription of the Preferred Embodlments Referring to Figures 1 to 4, there is shown a fastener of the kind specified, in this case a buckle 2. The frame 10 has a pair of opposed side walls 12 and 13. The frame 10 further comprises, at the pivot end of the frame 10, stops 17, elongate bores 18 and a wall 19. The end of the buckle 2 distant from the pivot includes, on the frame 10, a protuberance 23 and a further protuberance 26.

The lever 11, includes a latch 14 (Figure 4) which holds the lever temporarily in its locking position and eliminates the need for a separate latch release mechanism, thus allowing the buckle to be released more easily and hence faster. The lever 11 further comprises as part of the latch 14 an angular L-section 22, mounting members 20 and a further protuberance 25.

The buckle is released by the jerking of a strap, which (although not shown) passes through the buckle in the same way as the strap of specification No GB 2 226 377A. The strap end leaves the buckle end 15 and, when pulled up (i.e in the direction of arrow A in Figure 4) releases the latch and pivots the lever 11 clockwise. Alternatively, the buckle 2 may be released by the user lifting upwards the latch 14 which releases the temporary locking mechanism.

Referring now especially to Figure 2, there are twin pivot shafts 16 both centred about a common pivot axis 21. These can be moulded as an integral part of the frame 10 - or the lever 11 before fitting the lever to the frame; which would eliminate a production step. Alternatively, the pivot shaft could be incorporated at a later stage in the manufacture of the buckle, for example by inserting it and welding into place as described in specification No GB 2 226 377A with the lever first fitted into position in the frame.

The buckle frame 10 is so adapted that the base of the frame can be readily attached to a surface, by bolting through the elongate bores 18. The wall 19 runs across the run of the frame side walls 12, 13 so that the portion carrying the bores 18 is effectively a channel-section portion; the bolts (or other fixing devices) used to attach the buckle 2 to the appropriate surface are then chosen so that the tops of the fixing means do not protrude above the upper level of the wall 19, this prevents unnecessary wear on the strap.

The stops 17, which are situated behind the pivot shaft 16 on the base of the frame 10, limit the amount of opening (i.e prevent excessive opening) of the lever, which may otherwise result in damage to the buckle or the strap as the latch is jerked open.

They are in effect a multiple-protuberance construction.

The angular L-section 22 is attached to the body of lever 11 by mounting members 20. The L-section acts as a torsion member and provides the resilience to allow the latch to pass over the protuberance 23, and thus secure the buckle. The L-section 22 is integrally moulded as part of the frame 11 (although it may be attached thereto by other means) and its central region is held rigidly by the mounting members 20. However, the material chosen for the L-section 22 possesses sufficient resilience to allow the two ends 28 of the L-section 22 to twist with respect to the rigidly held central portion of the L-section - thus allowing for the requisite torsion.

The protuberance 23 is moulded as an integral part of the frame whilst the L-section 22 forms part of the lever. The abutting surfaces of the latch 14 and the frame 10 are curved so that force can be applied from virtually any normal direction to push the lever 11 into its locking position. Between the angular Lsection 22 and the rest of the lever these are notches 29 which act as stops engaging teeth 30 to delimit the freedom of movement of the flexible latch and to prevent the over-extension of the latch on opening and closing. The force to close the buckle is applied on, e.g curve 24 of the lever.

There are further protuberances 25 and 26 situated on the lever and frame respectively. On closing the buckle, the protuberances engage or very nearly engage such, that the shear forces eserted on the lever and the frame allows them to be load bearing or allow them to engage after a small amount of elastic extension and then share the load. Thus, the load on the buckle is spread between the two pins 16, the frame and the lever.

The shaded area 27 in Figure 2 is the flexible latch.

Figure 5 shows an open fastener 4 of substantially the same design as the buckle described above except that the side walls 12, 13 do not taper at the pivot end. Like numerals have been used to identify like parts and the description for Figs 1 to 4 also applies to Figure 5.

Normally, the buckle 2 will be injection moulded from a plastics material - other methods and materials may be used.

Claims

CLAIMS:

1. A fastener of the kind specified incorporating a latch to hold the lever temporarily in its locking position; characterised hr the feature that the latch comprises an extension of the lever and/or the frame and is allowed its latching action by virtue of the inherent torsional resilience of that portion of material which demarcates the latch region from the remainder.

2. A fastener according to Claim 1 characterised in that the latch is part of the lever.

3. A fastener according to Claim 1 or Claim 2 characterised in that the torsional resilience is provided by a torsion bar.

4. A fastener according to Claim 3 characterised in that the torsion bar is 'L'-shaped in cross section.

5. A fastener according to any preceding Claim characterised in that the pivot mounting the lever on the frame consists of twin shafts each serving to mount one respective side region of the lever and haring both centres about a common pivot axis.

6. A fastener according to Claim 5 characterised in that one of both pivot shafts is or are moulded as an ultimately integral part of the lever.

7. A fastener according to any preceding Claim in which a portion of the frame, lying in plane generally at right angles to the planes containing the frame side walls, is bored or otherwise adapted for securement to a surface - for example, a lorry side curtain - which is to carry the frame in use; characterised in that the said portion is a channel-section portion with a wail running generally across the run of the frame side walls.

8. X fastener according to any preceding Claim including the provision of stop means to limit the amount of opening (release) movement of the lever; characterised in that the stop means exhibits a multiple - protuberance construction.

9. A fastener of the kind specified substantially as described herein with reference to and as illustrated in Figures 1 to 4, or Figure 5, of the accompanying drawings.