GB2099062A - Latching key fob - Google Patents

Abstract

The key fob includes a first member (16) having a tapered latching spigot (20) and a second member (12) having a hole (14) for receiving a spigot. The spigot has a step (22) with a face extending transversely of the direction of spigot insertion, and the hole is defined by a relatively rigid first wall (24) and a relatively flexible second wall (26) disposed diametrically opposite, the second wall during spigot insertion is caused to distort by engagement with the spigot until the step face passes beyond the first wall when the second wall urges the spigot laterally of the direction of insertion to position and latch the step under the first wall. <IMAGE>

Description

SPECIFICATION Latch device This invention relates to a latch. According to one aspect of the invention there is provided a latch comprising a first member having a spigot and a second member having a hole for receiving the spigot, the spigot having a cross-sectional shape which reduces in size in the direction of insertion of the spigot in the hole and which has a step with a face extending transversely of said direction of insertion, the hole being defined by a substantially rigid first wall portion and by a flexible second wall portion disposed diametrically opposite the first wall portion, the latch being such that during insertion of the spigot in the hole, the second wall portion is caused to distort by engagement with the spigot until said step face passes beyond the first wall portion when the second wall portion will urge the spigot laterally of the direction of insertion to position and latch the step under the first wall portion.

An embodiment of 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 latch according to the invention and incorporated into a key tab or key fob, Figure 2 is a section along the line A-A in Figure 1, Figures 3a and 3b are enlarged detail views of the hole construction, and Figure 4 shows a sequence of sketches showing the latching operation.

Referring to the drawings, the key fob 10 is produced as an integral moulding of nylon, polypropylene or any other plastics material which provides rigidity with a little flexibility and resilience. The fob comprises a main body part 12 provided with a hole 14 and a strap 16 provided with integral hinges 1 8 and a spigot 20. In use the strap is fed through a key ring, hinged over and then secured to the body portion by latching or snapping the spigot 20 into the hole 14.

The spigot in the embodiment shown is of generally circular cross-section as viewed in Figure 1, and is tapered so that the cross-sectional area decreases or reduces in the direction of insertion of the spigot in the hole; the spigot is also provided with a step 22 having a face extending transversely of the direction of spigot insertion. The hole 14 is defined by a first wall portion 24 which is sufficiently thick (in this embodiment 1.1 5 mm) to make the portion substantially rigid. Diametrically opposite the first wall portion is a second wall portion 26 of thickness less than the first wall portion (in this embodiment 0.375 mm) to render it flexible.

In a modification, the cross-sectional shape of the spigot is rectangular, square or round such as oval.

Where a round cross-section is employed distortion of the spigot can be reduced by providing a cut-out 30 in the first wall portion; in the embodiment shown this cut-out is conveniently 1 mm wide and .325 mm deep.

To effect latching of the key fob, the spigot is presented to the hole (see Figure 4a) and is pushed axially therein. During insertion the spigot engages both wall portions 24 and 26 causing the second wall portion to distort (see Figure 4b).

When the face of step 22 passes beyond wall portion 24, the second wall portion urges the spigot laterally of the direction of insertion, to position and latch the step under wall portion 24 (see Figure 4c). To release the latch (see Figure 4c), a pointed tool 32 can be inserted into the rear opening of the hole to engage and move the spigot laterally out of contact with wall portion 24.

The thickness 'X' of the second wall portion 26 and the width Z of the hole (i.e. the distance between the all portions) determines the amount of effort required to fit the latch and also the final latching grip.

For bigger sizes of spigot dimensions 'X' and 'Z' will also be increased to maintain their ratio; in the present embodiment with 'X' at 0.375 mm Z, would be 2.625 mm.

1. A latch comprising a first member having a spigot and a second member having a hole for receiving the spigot, the spigot having a crosssectioned shape which reduces in size in the direction of insertion of the spigot in the hole and which has a step with a face extending transversely of said direction of insertion, the hole being defined by a relatively rigid first wall portion and by a relatively flexible second wall portion disposed diametrically opposite the first wall portion, the latch being such that during insertion of the spigot in the hole, the second wall portion is caused to distort by engagement with the spigot until said step face passes beyond the first wall portion when the second wall portion will urge the spigot laterally of the direction of insertion to position and latch the step under the first wall portion.

2. The latch of Claim 1, wherein the spigot is of round cross-section and wherein the first wall portion includes a cutout extending in the direction of insertion of the spigot.

3. The latch of Claim 1 or 2 in which the first and second members form part of a key fob.

4. A latch or key fob substantially as herein described with reference to the accompanying drawings.

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

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Latch device This invention relates to a latch. According to one aspect of the invention there is provided a latch comprising a first member having a spigot and a second member having a hole for receiving the spigot, the spigot having a cross-sectional shape which reduces in size in the direction of insertion of the spigot in the hole and which has a step with a face extending transversely of said direction of insertion, the hole being defined by a substantially rigid first wall portion and by a flexible second wall portion disposed diametrically opposite the first wall portion, the latch being such that during insertion of the spigot in the hole, the second wall portion is caused to distort by engagement with the spigot until said step face passes beyond the first wall portion when the second wall portion will urge the spigot laterally of the direction of insertion to position and latch the step under the first wall portion. An embodiment of 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 latch according to the invention and incorporated into a key tab or key fob, Figure 2 is a section along the line A-A in Figure 1, Figures 3a and 3b are enlarged detail views of the hole construction, and Figure 4 shows a sequence of sketches showing the latching operation. Referring to the drawings, the key fob 10 is produced as an integral moulding of nylon, polypropylene or any other plastics material which provides rigidity with a little flexibility and resilience. The fob comprises a main body part 12 provided with a hole 14 and a strap 16 provided with integral hinges 1 8 and a spigot 20. In use the strap is fed through a key ring, hinged over and then secured to the body portion by latching or snapping the spigot 20 into the hole 14. The spigot in the embodiment shown is of generally circular cross-section as viewed in Figure 1, and is tapered so that the cross-sectional area decreases or reduces in the direction of insertion of the spigot in the hole; the spigot is also provided with a step 22 having a face extending transversely of the direction of spigot insertion. The hole 14 is defined by a first wall portion 24 which is sufficiently thick (in this embodiment 1.1 5 mm) to make the portion substantially rigid. Diametrically opposite the first wall portion is a second wall portion 26 of thickness less than the first wall portion (in this embodiment 0.375 mm) to render it flexible. In a modification, the cross-sectional shape of the spigot is rectangular, square or round such as oval. Where a round cross-section is employed distortion of the spigot can be reduced by providing a cut-out 30 in the first wall portion; in the embodiment shown this cut-out is conveniently 1 mm wide and .325 mm deep. To effect latching of the key fob, the spigot is presented to the hole (see Figure 4a) and is pushed axially therein. During insertion the spigot engages both wall portions 24 and 26 causing the second wall portion to distort (see Figure 4b). When the face of step 22 passes beyond wall portion 24, the second wall portion urges the spigot laterally of the direction of insertion, to position and latch the step under wall portion 24 (see Figure 4c). To release the latch (see Figure 4c), a pointed tool 32 can be inserted into the rear opening of the hole to engage and move the spigot laterally out of contact with wall portion 24. The thickness 'X' of the second wall portion 26 and the width Z of the hole (i.e. the distance between the all portions) determines the amount of effort required to fit the latch and also the final latching grip. For bigger sizes of spigot dimensions 'X' and 'Z' will also be increased to maintain their ratio; in the present embodiment with 'X' at 0.375 mm Z, would be 2.625 mm. CLAIMS

1. A latch comprising a first member having a spigot and a second member having a hole for receiving the spigot, the spigot having a crosssectioned shape which reduces in size in the direction of insertion of the spigot in the hole and which has a step with a face extending transversely of said direction of insertion, the hole being defined by a relatively rigid first wall portion and by a relatively flexible second wall portion disposed diametrically opposite the first wall portion, the latch being such that during insertion of the spigot in the hole, the second wall portion is caused to distort by engagement with the spigot until said step face passes beyond the first wall portion when the second wall portion will urge the spigot laterally of the direction of insertion to position and latch the step under the first wall portion.

2. The latch of Claim 1, wherein the spigot is of round cross-section and wherein the first wall portion includes a cutout extending in the direction of insertion of the spigot.

3. The latch of Claim 1 or 2 in which the first and second members form part of a key fob.

4. A latch or key fob substantially as herein described with reference to the accompanying drawings.