GB2258007A - Fastener for a bracelet. - Google Patents

Abstract

A bracelet (1) is disclosed which comprises two substantially curved elongate pivotably interconnected rigid members (2, 8). One member (8) has a set of teeth (10) at one end and the other member (2) has a pivotably mounted pawl (12) at one end. The pawl (12) is provided with a tooth (22) which can resiliently engage with at least two adjacent teeth of the set of teeth (10). Fitment or release of the fastener is effected by pivotal movement of the paw (12) and the free ends of the first and second members (8, 2) may be brought together or separated. <IMAGE>

Description

FASTENER FOR A BRACELET This invention relates to fasteners primarily but not exclusively for bracelets.

A number of bracelet fasteners are well known.

They include straps having a buckle and holes. These straps can be difficult to fasten. Other bracelet fasteners include expanding bracelets and endless bracelets with portions which clip together. Both may be insecure and the latter is also difficult to adjust. The invention seeks to provide an improved fastener. The fastener of the invention may have aesthetic appeal to some users and may be readily but securely fastened and easily adjusted.

According to the invention there is provided a bracelet or some other article having a fastener comprising a plurality of ratchet teeth engagable by a pawl. The pawl can be resiliently biased to engage the ratchet teeth the arrangement being such that opening of the fastener is resisted but closure is allowed.

A bracelet in accordance to the present invention can comprise a first substantially elongate shaped rigid member having a set of teeth at one end; a second substantially elongate shaped rigid member having a pawl means pivotably mounted thereto at one end and pivot means connecting the other ends of the first and second members together, wherein the pawl means is provided with a resiliently biased pawl tooth which can resiliently engage with at least two adjacent teeth of the set of teeth to form a releasable fastener so that fitment or release of the fastener is effected by pivotal movement of the pawl and the ends of the first and second members opposite the pivot means may be brought together or separated.

It is preferable that at least one rigid member is generally "U" shaped or curved and such a bracelet may be a strap fitted with a timepiece.

In one embodiment, the teeth of the first member are ratchet teeth so as to permit free relative movement of the first and second members in one direction.

It is preferred that the distance of any valley between the teeth to the pivot axis connecting the first and second member is at least equal to the distance of the tip of the pawl tooth to said pivot axis before engagement in order to ensure that the pawl tooth engages the teeth when the fastener is locked.

In a preferred embodiment, the pawl may be locked in the engaged position so that an unintentional release of the first rigid member from the second rigid member is not possible. The first and/or the second rigid members may themselves comprise two or more substantially identical members lying in a parallel spaced apart relationship.

In order that the invention may be more readily be understood, reference will now be made to the accompanying drawings, wherein: Figure 1 is a perspective view of the main components of a bracelet or wrist strap with one embodiment of a fastener made in accordance with the invention; Figure 2 is a perspective view of the main components of the bracelet shown in Figure 1 in a disassembled state; Figure 3 depicts the bracelet of Figure 1 unfastened and around a wrist; Figure 4 depicts the bracelet of Figure 1 fastened around a wrist; Figures 5 to 7 depict the range of adjustment possible with the bracelet shown in Figures 1 to 4; Figure 8 is a perspective exploded view of the main components of a further embodiment of a bracelet with another fastener made in accordance with the invention;; Figure 9 is a side view of the further embodiment with the principle components shown in a disassembled state; Figures 10 to 13 depict the further embodiment at various stages of fastening and unfastening; and Figures 14 to 17 depict respectively, the pivot arrangement, the pawl arrangement, the underside and the top of the bracelet shown in Figure 8.

With reference to the drawings, there is shown in Figure 1 for example, an assembled bracelet usable as a watch strap 1 having a fastener made in accordance with the invention, ready for the fitment of a timepiece.

The strap 1 is composed of a first substantially rigid member 8 pivotably connected to a second substantially rigid member 2 with the aid of pin 6 which interconnects the members 2, 8 and engages in locating holes 30, 32.

The second substantially rigid member 2 comprises two spaced apart plates 3 and 4 which are generally fuf shaped such that for example they may partially extend around a wrist. The members 3, 4 are substantially rigid and preferably manufactured from a metal, plastics or composite material and may typically be pressings or mouldings. The members 3 and 4 are connected together at the opposite end to the pivot pin 6 by connecting pins 14 and 15 engaging in locating holes 34, 35, 36, 37. The connecting pins 14, 15 can be provided with reduced diameter end regions which pass at least partially through the holes 34, 37 in the members 3, 4. The pins 14, 15 have shoulders which engage on the members 3, 4 to space these components apart.A timepiece (not shown) may be attached to the members 3 and 4 by attachment means which may consist of lugs or holes 38, 40 within the members 3, 4.

The member 8 is also generally 'U' shaped and may be of similar material to members 3 and 4. At the end opposite the pivot pin 6, the member 8 is equipped with a set of teeth 10. The teeth 10 extend parallel with the pivot axis of the pin 6.

A complementary pawl 12 with a tooth 22 is positioned between the members 3 and 4 at the end opposite the pivot pin 6. The pawl 12 is pivotably mounted to the members 3, 4 intermediate its ends by a pin 20, in order that it may flex and pivot thereabout as the crests of the ratchet teeth 10 contact the tip of the pawl tooth 22. The pin 20 engages in holes 42, 44 in the members 3 and 4.

As may be seen from Figure 2, the pawl 12 is equipped with a groove 18 at the end remote from the tooth 22 and is adapted to rest against the connecting pin 15. The pawl 12 also possesses a lip 24 disposed at the other side of the tooth 22 and remote from the groove 18. By pulling the lip 24 away from the teeth 10 the pawl tooth 22 may be readily disengaged from the teeth 10.

Figures 3 and 4 show the use of the watch strap with a timepiece 50 fitted whilst placed around a wrist 52. A small section of the member 2 is cut away to show the working of the pawl mechanism. Figure 3 shows the watch strap unfastened. Figure 4 shows the watch strap fastened with the member 8 engaged by the pawl tooth 22.

Figures 5a, 6a and 7a exhibit the range of adjustment possible with a watch strap having fastening means made in accordance with the invention. Figure 5b, 6b and 7b correspond to the above Figures but have a section of the member 3 cut away to show the position of the pawl tooth 22 with respect to the ratchet 9.

The arrangement of the pawl 12 and the teeth 10 is such that closure of the strap 1 about the wrist 54 is relatively easy. The sloping portions of the ratchet teeth 10 bear against the pawl tooth 22 and resiliently bias it way from its rest position. When the pawl tooth 22 passes a tooth crest of the first member 8 the pawl tooth 22 is urged back into a valley defined between adjacent ratchet teeth 10 as a snap-fit. In the embodiment exemplified, the biasing may be due to the inherent resiliency of the pawl 12. Alternatively or additionally bias may provided for example by a spring, to the pawl 12 urging it to the rest position.

Attempts to widen the strap 1 by pulling the pawl 12 and ratchet-shaped teeth 10 in opposing directions are unlikely to be successful. If it is attempted the flat face of a ratchet tooth 10 will engage the flat face of the pawl tooth 22. A relatively large amount of force is required to deform the mechanism sufficiently to release the fastener.

If it is desired to release the fastener it is first necessary to disengage the pawl 12 and the ratchet 9 properly. This may conveniently be done by manually overcoming the resilient bias acting on the pawl 12 for example by levering the lip 24 away from the ratchet teeth 10. When disengaged it is a simple matter to open the strap 1 by separating the free ends of the two rigid members -3, 4 which then pivot about the pin 6.

Figure 8 depicts a further embodiment of the invention wherein like reference numerals denote like parts to the previous embodiment . In this further embodiment the teeth 10 of the first member 8 are not ratchet shaped and the pawl 12 has a separate spring biassing means 66. The pawl 12 is preferably formed from a metal sheet, with projections 20 projecting from the sides so that it may locate in holes 42, 44 in the second member 3, 4 about which it may pivot. A safety catch 68 is also provided which is also preferably formed from a pressed metal sheet. In a similar fashion to the rigid member 2, the first rigid member 8 is also composed of two spaced apart 'U'- shaped plates 76, 78. Spacer pins 13, 14, 15, 80 are disposed between these 'U' - shaped plates 76, 78.The spacer pins 13, 14, 15, 80 and the pivot pin 6 are retained to the 'U' - shaped plates 2, 4, 76, 78 by retaining means such as screws 84. Figure 9 details the 'U' - shaped plates 2, 4, 76, 78 together with the pawl 12, the spring biasing means 66 and the safety catch 68. The co-action of the pawl 12 with the teeth 10 will now be explained with reference to Figures 10-13. Figure 10 shows the fastener with the safety catch 68 in a locked position, with a small projection 86 preventing the safety catch 68 from slipping out of the locked position. Figure 11 shows the safety catch 68 in an unlocked position after it has been moved in the direction indicated by arrow "a" with a sufficient force to overcome the resistance provided by the projection 86.

The safety catch 68 can now be pressed (Figure 12) in the direction shown by arrow "b" and this in turn, presses the pawl 12 against the force of the spring biasing means 66 so that the pawl 12 pivots about the holes 42, 44. The pawl 12 then becomes disengaged from the teeth 10 of the first member 8 and the two released ends of the first and second members 8, 2 may be separated as before.

Since in this embodiment the teeth 10 are not ratchetshaped, closure of the fastener is effected by the reverse procedure.

Although the invention has been illustrated by reference to a bracelet, it will be apparent that the fastener is usable in other forms, for example, as a shoe fastener or as a clothes fastener.

Claims (9)

1. A bracelet or strap comprising a first substantially elongate shaped rigid member having a set of teeth at one end; a second substantially elongate shaped rigid member having a pawl means pivotably mounted thereto at one end and pivot means connecting the other ends of the first and second members together wherein, the pawl means is provided with a resiliently biased pawl tooth which can resiliently engage with at least two adjacent teeth of the set of teeth to form a releasable fastener so that fitment or release of the fastener is effected by pivotal movement of the pawl and the ends of the first and second members opposite the pivot means may be brought together or separated.

2. A bracelet according to Claim 1 wherein at least one of the rigid member is generally 'shaped or curved.

3. A bracelet according to Claims 1 and 2, wherein there is provided means to mount a timepiece.

4. A bracelet according to any one of Claims 1 to 3, wherein the teeth of the first member are ratchet teeth so as to permit relative movement between the teeth and the pawl in one direction without external disengagement of the pawl means.

5. A bracelet according to any one of Claims 1 to 4, wherein a locking mechanism is provided to prevent accidental movement of the pawl effecting the release of the first member unintentionally.

6. A bracelet as according to any one of Claims 1 to 5, wherein one or both rigid members comprises several substantially identical members lying in a spaced apart relationship.

7. A bracelet according to any one of Claims 1 to 6 wherein the pawl means is resiliently biased with a spring.

8. A fastener for releasably connecting the free ends of two members together; said fastener comprising a set of teeth on the free end of one of the members, pawl means pivotably mounted on the free end of the other of the members, the pawl means having a tooth engageable between a pair of teeth of said set of teeth, means biasing the pawl means to hold the tooth thereof between the pair of teeth to fasten the free ends together and contact means on the pawl means which serves to enable a user to overcome the biasing force and release the pawl tooth from the set of teeth to enable the free ends to be separated.

9. A bracelet or fastener substantially as described herein with reference to any one of the accompanying drawings.