GB2281589A - A child-proof lock for a cupboard - Google Patents

Abstract

A child-proof lock for a cupboard comprises two push buttons (22, fig 1) spaced apart, eg by 11 to 18 centimetres, so that a child is not capable of hand operating them simultaneously in order to release the lock. When the buttons are simultaneously depressed against the bias of a spring (114, fig 4) feet 110 are disengaged from key-hole slots 76 so that main member 56 is allowed to slide when cam 90 is rotated by a handle. The siding of the main member 56 releases a latch member 58 from striker plate 30, the motion being transferred via flanges 64 and cross-piece 78. Springs 86 and 88 bias the main member 56 and latch member 58 back to their locking positions. In the locking position the face 104 of cam 90 contacts edge 64 (see fig 2). Cam 90 may be dispensed with and replaced by a slider (fig 7) which acts directly on main member 56. <IMAGE>

Description

Title: Child Restraining Lock BACKGROUND TO THE INVENTION THIS invention relates to safety locks for cupboards and the like.

The invention is concerned with a safety lock for a cupboard or the like of the kind comprising a container body; a door movable between an open and a closed position, in the latter of which it closes the body; an abutment surface on body; a locking mechanism including a catch carried by the door, the locking mechanism being movable between a locking position and a release position, so that (a) when the door is in the closed position and the catch is in the locking position, the catch engages the abutment surface and (b) when the door is in the open position, the catch is remote from the abutment surface; and manually operable moving means for moving the catch from its locking position to its release position.

SUMMARY OF THE INVENTION According to one aspect of the invention there is provided a lock bolt movable between locked and unlocked positions; manually operable moving means connected to the lock bolt for moving the lock bolt between its locked and unlocked positions; disengageable retention means for retaining the lock bolt in its locked position; and manually operable release means associated with the retention means and adapted to disengage the retention means, said release means being configured for operation by an adult sized hand but not being operable by a child sized hand.

Preferably the release means comprises a pair of spaced apart depressible buttons, the buttons being spaced apart by a distance which is greater than the span of a child's hand.

The heads of the buttons are preferably so arranged that they do not stand proud of the front face of the door on which the lock assembly is mounted.

The moving means preferably comprises a knob which is rotatable to move the catch when the release means is operated. The moving means may however comprise a slide. The moving means is preferably located further from the release means than are the buttons of the release means are apart.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is an isometric view of a cupboard of the invention; Figures 2 & 3 are views of a locking mechanism on the inside of the cupboard in its inoperative and operative conditions respectively; Figures 4 & 5 are respectively sections on lines 44 and 5-5 of Figures 2 and 3; Figure 6 is a section on line 6-6 Figure 2; Figure 7 is a section of an alternative arrangement of that shown in Figure 6; and Figures 8 & 9 are respectively sections on lines 8-8 and 9-9 of Figures 2 and 3; and Figure lOa-f are schematics of further configuration of the invention.

Referring now to the drawings, there is shown a cupboard 10. The cupboard 10 has a cabinet 12 with an open front face that is closed by a door 14 hinged at one end 16 to a side of the cabinet 12. The other end 20 of the edge of the door 14 can be locked to the cabinet 12 as will be described below. A pair of release buttons 22 and an opening knob 24 are provided on the door 14. The location and operation of these parts will be described below.

On the inside surface 26 of the door 14 is a locking mechanism 28 which, as will be described cooperates with an abutment surface or striker plate 30 carried by cabinet 12 on the side remote from the hinges. The locking mechanism 28 is mounted in a 'T'-shaped carrier 32 carried by the door 14.

The leg 31 of the carrier 32 has peripheral side rims 34 with two pairs of rectangular guides 36, 37 projecting inwardly therefrom. At its free end, the leg 31 has a further pair of guides 38 which are more closely spaced than the other guides 36, 37. Two rectangular pins 40, 42 are provided on centre line of the leg 31. A main circular opening is also provided on the centre line of the leg between the two pairs of guides 37 and 38, and nearer to the cross-piece 44 is a round ended rectangular opening 46.

The cross-piece 44 of the carrier 32 has a pair of openings 48 surrounded by bosses 49 near its ends and a pair of hollow bosses 50 spaced slightly inwardly of the openings 48.

Wood screws 52, with washers 54, pass through the bosses 50 to engage the door 14 and fix the carrier 32 thereto. Another pair of wood screws also pass through openings (not shown) in the plate 84 and holes 55 in the leg of the carrier 32.

The locking mechanism 28 comprises a main"T'-shaped member 56 and a smaller T-shaped member 58.

The leg 57 of the main member 56 is slidable between the guides 36 and 37 and terminates in an enlarged portion 60 which fits between the rims 34 and is of smaller length than the distance between the guides 37 and 38. Thus the guides 37 and 38 limit the movement of the leg 57 in the carrier 32. This enlarged portion 60 has a rectangular opening 62 therein, there being a pair of inwardly directed flanges 64 at its end.

The ends of the flanges 64 are spaced apart by the same distance as the guides 38.

Elongated slots 66 and 68 are formed in the legs 59 and 57 and receive the pins 40 and 42 respectively. A small circular bore 70 is provided between the enlarged portion 60 and the end of the slot 68.

The cross-piece 72 of the main member 56 has a pair of round ended slots 74 in which the bosses 50 are received. Two rounded key-hole slots 76 are located in register with the openings, 48.

The cross-piece 78 of the smaller member 58 fits in the opening 62 and its leg 59 is slidable between the ends of the flanges 64 and the guides 38. The free end of the leg 59 is shaped to comprise the latch 82.

A cover plate 84 secured to the carrier 32 by bolts (not shown) passing through the guides 36 and 37 covers the leg 57 of the main member 56 including the enlarged portion 60. Additionally self-tapping screws pass through the cover plate and engage in holes 85 in the end guides 38.

Springs 86, 88 are provided respectively between (a) the pin 42 and the end of the slot 68 and (b) the pin 40 and the end of the slot 66. These springs 86, 88 bias the locking mechanism 28 towards the edge 20 of the door (which position is hereinafter called the "locking position").

Within the opening 62 is a double lobed generally triangular cam 90.

This cam 90 is engaged by a square section pin 92 projecting from a shaft 94 carried by the knob 24. This shaft 94 is rotatably carried in a bush 96 located by the boss 98 in an opening 100 in the door 14. The knob 24 has a transverse head 102 that can be easily gripped and rotated. A retention screw (not shown) engages the shaft 92. It passes through a washer 103 that rests on the cam 90 and thus holds the knob 24 in position.

The cam 90 is movable from a forward position as shown in Figure 3 and a rear position as shown in Figure 2. In the forward position, the flat surface 104 between the lobes 91 lies transverse to the axis of the leg 57 so that the end surface of the enlarged portion 62 is closest to the axis of the shaft 94. This means that main member 56 can be moved forwardly under the bias of the spring 86 towards the edge 20.

Consequently the smaller member 58 will be able to move under the bias of the spring 88 into a forward or locking position in which it engages the abutment 30 to lock the door 14 to the cabinet 12. In the rear position of the cam 90, one lobe 91 projects rearwardly from the shaft 94 in the direction of the leg 57 of the main member 56 so that its end is further from the axis of the shaft 94. The lobe 91 thus holds the main member 56 in a retracted position. In moving to this retracted position, the main member 56 through the flanges 64 retracts the smaller member 58 into a position in which the latch 82 is in a release position inwardly of the edge 20 and spaced from the abutment 30.

A pair of retention devices 106 is provided. Each device (which is best shown in Figures 4 and 5) comprises the release button 22 on the inside of which is formed a shaft 108 carrying a circular section foot 110. The button 22 is slidable in a flanged bush 112 passing through the door 14 so as to be accessible from the front of the door 14. The boss 49 is engaged in the bush 112. The shaft 108 passes through the opening 48.

The foot 110 fits into the larger section portion of the key-hole opening 76 when the main member 56 is in the forward position and is larger than the leg thereof. A spring 114 biases the retention device 106 outwardly so that the button 22 is flush with the trim rings 116 of the bush 112 on the outside surface of the door 14. It will be seen that as the foot 110 fits into the key-hole opening 76, the main member 56 will not be able to move from the forward position. The button 22 can be depressed against the bias of the spring 114 so that the foot 110 is clear of the cross-piece 72 of the main member 56. When this occurs at both buttons 22, the main member 56 can be moved to the retracted position.

It will be seen therefore that the door 14 can be opened by depressing both the buttons 22 and turning the knob 24 so that the cam 90 is in the rear position with the consequent movement of the latch 82 to the release position.

The buttons 22 are located sixteen centimetres apart. This is greater than the span of the hand of a child under, say, nine years of age, but is within the span of the hand of an adult. Therefore a child cannot depress both buttons and at the same time turn the knob 24. It follows that the locking mechanism 28 is child proof and the possibility of a child opening the door 14 to be able to have access to the contents of the cabinet 12 is eliminated or substantially eliminated.

Reference is now made to Figure 7. In the embodiment here shown, a slider button 118 is provided in substitution for the rotatable knob 24.

This slider 118 comprises a hollow cylindrical spacer 120 that is slidable in slot 122 in the door 14. A bolt (not shown) passes through hole 70 in the leg 57 of the main member 56 and through spacer 120 to secure the slider button 118 to the leg 57. A flange 128 surrounds the button 22 to cover the slot 122 in the door 14.

The distance of the retention buttons 22 to the slider button 118 is eleven centimetres, again too far for a child's hand to operate more than one of the necessary items for moving the locking mechanism 28 to the release position.

Operation of this embodiment is analogous to that of the first described embodiment.

The disposition of the retention buttons 22 and the knob 24 or slider 118 relative to the latch 82 (all these parts being indicated by the same reference numerals) can vary as shown for example in Figure 10.

The invention is not limited to the precise constructional details hereinbefore described and illustrated in the drawings. For example the distance between the retention button 22 may vary provided that they are spaced apart by a distance greater than the span of a child's hand but sufficiently close to be within the span of an adult's hand. In general terms the span of a nine year old child's hand is about eleven centimetres which is considerably smaller than the spacing between release button 22. The span of an adult's hand may be of the order of sixteen centimetres.

Claims (16)

1. A lock assembly comprising; a lock bolt movable between locked and unlocked positions; manually operable moving means connected to the lock bolt for moving the lock bolt between its locked and unlocked positions; disengageable retention means for retaining the lock bolt in its locked position; and manually operable release means associated with the retention means and adapted to disengage the retention means, said release means being configured for operation by an adult sized hand but not being operable by a child sized hand.

2. A lock assembly according to claim 1 wherein the release means comprises a pair of spaced apart depressible buttons, the buttons being spaced apart by a distance which is greater than the span of a child's hand.

3. A lock assembly according to claim 2 wherein the buttons are spaced apart by between 11 and 18 centimetres.

4. A lock assembly according to claim 2 or 3 wherein the buttons have a height which is approximately the same as the thickness of a panel on which the lock assembly is adapted to be mounted, the buttons adapted to pass through holes bored in the panel with the outer ends of the buttons lying approximately flush with the outer surface of the panel.

5. A lock assembly according to any preceding claim wherein the moving means comprises a knob which is rotatable on an axis to move the lock bolt.

6. A lock assembly according to claim 5 wherein the knob carries a cam adapted to engage a drive surface on the lock bolt, rotation of the knob bringing the cam into engagement with the drive surface.

7. A lock assembly according to any one of claims 1 to 4 wherein the moving means comprises a slide.

8. A lock assembly according to any preceding claim wherein the lock bolt comprises a latch which is spring biased into its locked position.

9. A lock assembly according to any one of claims 1 to 6 wherein the lock bolt comprises a dead bolt, which is movable both towards and away from its locked position by said moving means.

10. A lock assembly according to claim 8 wherein the latch bolt comprises a catch and a retraction member, the catch being movable relative to the retraction member and being spring biased against the retraction member into a locked position, said moving means adapted to move the retraction member and the catch to said unlocked position.

11. A lock assembly according to claim 10 wherein the catch and the retraction member are independently spring biased into the locked position.

12. A lock assembly according to claim 2 wherein the lock bolt is of generally T-shaped configuration, said buttons being mounted on respective opposite ends of the arm of the T, each of said buttons passing through a respective slot, said slots being aligned generally parallel to the leg of the T, said slots having a key-hole shaped configuration, said buttons having a base configured to seat within a wide diameter portion of the slot and being spring biased into engagement with the slot, the arrangement being such that with the lock bolt in its locked position the bases of the buttons will be aligned with their respective wide diameter portions of the slot and will each move under the action of their respective spring bias so that the bases engage in the wide diameter portion, said buttons being depressible to move their bases out of engagement with the respective wide diameter portion of the slots to permit the lock bolt to move between its locked and unlocked positions.

13. A lock assembly according to claim 12 wherein the leg of the T is constrained to move within guides on a guide plate, said guide plate adapted to be mounted to a panel on which the lock assembly will be mounted in use.

14. A lock assembly according to any preceding claim wherein the lock bolt, moving means, and release means are made from a plastics material.

15. A lock assembly substantially as hereinbefore described with reference to the drawings.

16. A cupboard having a lock assembly according to any preceding claim mounted to a door thereof, said lock bolt adapted to engage a slide mounted to a surround to the door.