GB2160251A - Lockable door fastener - Google Patents

Abstract

A releasable fastener includes a spring-loaded catch which can be locked to prevent access from one side of a door to which the fastener is fitted. The catch eg ball 2 is preferably fitted with locking means that are actuated by sliding a shaft 5 which provides attachment for a door handle. In the case of a ball catch, a cam 17 attached to the shaft 5 moves a push rod 22 towards the ball 2 whereby the ball is locked in a keeper in the door frame. A mortice type of catch, housing a spring-loaded slide, is also disclosed (Fig. 3, not shown) and in this case a stop attached to the shaft prevents movement of the slide. <IMAGE>

Description

SPECIFICATION Releasable fastener This invention relates a releasable fastener which includes a spring-loaded catch. The invention has particular (but not exclusive) application in securing a pivoted door, e.g. a bathroom and/or a toilet door, where it is necessary to prevent access from one side.

Known types of spring-loaded door catches include, for example, ball catches and the mortice type.

In a ball catch, a spring-loaded ball is usually mounted in a sleeve set in one edge of the door, the ball being urged outwardly to engage a keeper in the door frame. Whilst the catch normally secures the door, the door can be pushed open because there is nothing, except the bias of the spring, to prevent the ball from riding over the keeper.

In the mortice type, a spring-loaded slide has a wedge shaped end which engages a keeper mounted on the door frame. The slide is moved, so as to disengage the wedgeshaped end from the keeper, when a square section shaft is rotated by means of a door handle. This type of catch may be either an independent mechanism, or contained in a housing which includes a separate morticelock for locking the door. With an independent mortice type of catch and with the ball catch, a separate lock, such as a bolt, is required to secure the door.

One of the aims of the present invention is to eliminate the need for separate door locks.

This not only reduces the time and expense for manufacture and installation but also improves the appearance of the door, particularly where expensive and/or elegant door furniture is employed.

The present invention provides a releasable fastener comprising a spring-loaded catch and a shaft which provides attachment for a handle, the shaft being slidable into a position to inhibit operation of the catch from at least one side.

The catch may be, for example, one of the mortice type where the shaft rotates in order to operate the catch. In this case, at least the shaft slides sufficiently relative to a handle (e.g. fitted to a door which is fastened by the catch) so that the shaft becomes operably disengaged from the handle (hence preventing access from one side of the door). However, where the catch is not operated by the shaft (as in a ball catch), and as a matter of preference, locking means are provided for inhibiting the operation of the catch when the shaft is in a locking position. The locking means may act either directly on the catch or an extension of the catch, or it may indirectly operate the catch by means of at least one intermediate member, such as a push-rod.

In a preferred embodiment of the invention, detent means are provided for locating the shaft in an unlocking positon. This advantageously ensures that the shaft does not slide into its locking position when the handle is used to close e.g. a door to which the releasable fastener is fitted.

In a preferred embodiment of the invention, the releasable fastener is fitted to an openable member, such as a pivoted door, a first handle being attached to the openable member for receiving one end of the shaft. When the handle is pulled to swing the door open, the catch is unlocked by the slidable movement of the shaft. However, when the handle is pushed, the shaft slides into its locking position so as to lock the catch. This embodiment of the invention may be advantageously applied where elegant door furniture is used, eg. where the handles are in the form of brass door knobs or levers, since the appearance of the door is substantially unchanged, whilst the catch may be locked simply by pushing the handle to close the door.

In an alternative embodiment of the invention, handles are attached to each side of an openable member, such as a door, which is fitted with the releasable fastener. These handles are provided for causing rotation of the shaft to operate the catch. One end of the shaft extends through one of these handles and an operating knob is fitted to this extending end of the shaft for causing the shaft to slide into a locking position (where the preferreed locking means locks the catch).

In some cases (e.g. with a bathroom and/or toilet door), it may be necessary to open the door from the outside in an emergency. To allow for this, the handle which becomes operably disengaged from the end of the shaft (when the shaft is in its locking position) is provided with an aperture for receiving a releasing member. The releasing member may be a thin piece of wire which is used either to push the shaft, or (when the end of the wire is formed into a hook) to engage the end of the shaft to enable it to be pulled so as to slide the shaft out of its locking position.

Embodiments of the invention will now be described with reference to the accompanying schematic drawings, in which: Figures 1 and 2 are views, partly in section, of a releasable catch according to one embodiment of the invention, Fig. 1 showing a ball catch in an unlocked position and Fig. 2 showing the ball catch in a locked position.

Figure 2A shows a detail of one end of a sleeve used in the ball catch; Figure 2B shows a detail of the end of a sleeve used in the ball catch; and Figure 3 illustrates, partly in section, another embodiment of the invention which employs a mortice type of catch.

Referring to Figs. 1 and 2, a spring-loaded ball catch 1 includes a ball 2 and a spring 3 mounted in a sleeve 4. A shaft 5 (of square cross-section) is slidably mounted in apertures 6 and 7 on the opposite sides of the sleeve 4.

One end 8 of the shaft 5 is received in a recess 9 (of square cross-section) in the stem of a handle 10 and is secured by means of a screw 11. Handle 10 is therefore fast with shaft 5 and it can be moved relative to a base plate 12 secured by means of screws (not shown).

A generally similar handle 14 is mounted on the other side of door 1 3 except that handle 14 is retained by its base plate 1 2.

The (square section) recess 1 5 of handle 14 slidably receives a chamfered end 16 of shaft 5. The shaft 5 is free to slide into recess 1 5 when the handle 10 is pushed.

A wedge-shaped cam, having a flat top 17a, is attached to shaft 5 and it has an inclined face 18 which bears against a rounded end 1 9 of push rod 20 slidably mounted in spaced apertured members 21 and 22 which are fixed to the inside of sleeve 4. In the "unlocking" position, as shown in Fig. 1, push rod 20 is free to slide in members 21 and 22, its other end 23 being shown spaced apart from the ball 2. However, when the handle 10 is pushed inwardly to close the door as shown in Fig. 2, the shaft 5 slides into the door and the inclined face 1 8 of cam 1 7 causes the push rod to move towards the ball 2 until the rounded end 1 9 of the push rod slides onto the flat top 1 7a of cam 17.

The end 23 of push rod 20 then restricts movement of ball 2 (i.e. the movement which normally occurs against the bias of spring 3) so as to maintain the ball 2 in a (locking) position in a keeper 24 set into a door frame 25. Hence, the door 1 3 cannot then be opened, e.g. by pushing against knob 14.

In order to release the spring-loaded catch 1, the handle 10 is simply pulled to open the door and it slides back into the position shown in Fig. 1. As shown in both Fig. 1 and Fig. 2, a (drilled) hole 25 in the door 1 3 accommodates the cam 1 7 in each of its unlocking and locking positions. Most doors (e.g. a standard door is about 35mm thick) are thick enough to accommodate the necessary movement of the cam 1 7.

A particular advantage of the arrangement shown in Figs. 1 and 2 is its ease of installation. Only two holes of the same diameter, (e.g. 19-22mm) need to be drilled, one into the door 1 3 to accommodate shaft 5 and cam 17, and the other into the outer stile or edge of the door to accommodate the sleeve 4 of the ball catch 1. To facilitate installation of the ball catch 1, the outer end of the sleeve 4 is turned back and formed into a plurality of sharpened teeth 4a (see Fig. 2A) for securing the sleeve in the edge of the door. This obviates the need for chisel work, e.g. to incise a recess for an attachment plate otherwise fitted to the outer end of sleeve 4.

It is to be noted, from Figs. 1 and 2, that apart from the extension of the handle 10 when the door is open there is no external appearance of a locking mechanism on door 1 3. All that is visible is the space between handle 10 and its base plate 1 2 when the fastener is in its locking position, but this is normally on the side of the door which opens towards a wall and is hence not generally noticeable.

Detent means 26 prevents the shaft 5 from accidently moving into its locking position when the handle 10 is pushed to close the door 1 3. The detent means 26 includes a ball 27 (or friction pad, not shown) and a spring 28 mounted in a sleeve 29. A screw 30 secures (or abuts) one end of spring 28 and extends through an aperture in the base of sleeve 29.

The end of the screw is secured by a nut 31 to a flattened and turned up end portion 32 of sleeve 4 (see Fig. 2B), the nut 31 also facilitating adjustment of screw 30 to adjust the force exerted by the spring 28. The end portion 32 is received in the hole drilled in the edge of the door 1 3 (for receiving sleeve 4). The ball 27 is urged, by the spring 28, towards the shaft 5. When the fastener is in the locking position shown in Fig. 1, ball 27 is located in a part-spherical recess 34 (shown in broken lines) in the shaft 5. The spring 28 is sufficiently strong (and/or the screw 30 is adjusted) to prevent the shaft 5 from sliding when the handle 10 is pushed (in the direction of the arrow shown in Fig. 1) to cause the door 1 3 to move towards the door frame 13' and to cause the ball 2 to engage with the keeper 24 in the frame.However, as shown in Fig. 2, when the handle 10 is then pushed harder (the ball catch 1 is then engaged), the ball 27 disengages from recess 34 to enable the shaft 5 to slide into its locking position.

The fastener shown in Figs. 1 and 2 is particularly suitable for use on a door to which access is denied from the outside, e.g.

a toilet door. However, in order to gain access in the case of an emergency, a releasing member can be used to displace the shaft 5 from its locking position. As shown in Fig. 1, the releasing member comprises a piece of stiff wire 35 which can be inserted through a central aperture 37 (which is coaxial with shaft 5) in the handle 14 and used to push the shaft 5 out of its locking position.

In the embodiment of Figs. 1 and 2, the shaft 5 and the recess 9 and 1 5 are of square section, since the handles and the shaft are of conventional design. However, the shaft could have a different cross-section because it only needs to be attached at one end to handle 10 (since the shaft 5 is not used to operate the catch). On the other hand, Fig. 3 illustrates a mortice type of door catch in which a shaft of square cross-section is rotated by a handle on either side of a door in order to operate a spring-loaded catch.

Referring to Fig. 3, a spring-loaded catch 40 includes a slide 41 having a wedgeshaped end 42 for engaging a keeper (not shown) in a door frame (not shown). The slide is free to move in a housing 43 (indicated schematically by the broken lines only). A stop 44 is anchored to the housing 43 so as to abut a spring 45 for urging the end 42 outwardly of a mounting plate 46. A snailshaped cam 47 is secured for rotation in the housing 43, the cam having a through aperture 48 for slidably receiving shaft 49. The aperture 48 and the shaft 49 each have a square cross-section. The cam 47 engages a tab 50 attached to the slide 41 so that when the shaft 49 is rotated the tab 50, and hence the slide 41, is moved away from the mounting plate 46 against the bias of spring 45.

The shaft 49 has a chamfered end 51 which is located in a recess 52, of square crosssection, in a handle 53. The other end of the shaft extends through an aperture 54 in a handle 55 and terminates in a screw thread 56 to which a threaded knob 57 is attached.

Both handles 53 and 55 are rotatably secured in respective door mounting plates 61 of conventional constructon. Since both handles 53 and 55 are normally located on the shaft 49, either may be turned to move the slide 41 to open the door.

An L-shaped member 58 is attached to the shaft 49 adjacent the chamfered end 51. The housing 43 has an aperture 59 through which a limb 58' of member 58 passes when the shaft 49 is moved in the direction of arrow 60 (by pulling knob 57).

When limb 58' has entered aperture 59) it acts as a stop to prevent movement of slide 41, hence locking the wedge-shaped end 42 in the keeper (not shown) which is attached to the door frame (not shown). Morever, when the shaft 49 has been moved in the direction of arrow 60, the chamfered end 51 is withdrawn from the recess 52 in the handle 53 and hence turning the handle 53 does not have any effect on shaft 49.

Both handles 53 and 55 are spring-loaded in the door plates 58 in a conventional manner, e.g. so that they remain in a substantially horizonal position.

An advantage of the embodiment shown in Fig. 3 is that the mortice catch 40, the shaft 49, the handles 53, 58 and door plates 58 are of basically conventional design, the only essential differences being that hole 59 is provided in the catch housing 43, the Lshaped stop 58 is attached to shaft 49 and handle 53 is apertured to enable slidable movement of the shaft 49. Thus, a conventional catch can be easily modified in accordance with the invention.

A releasing member 35 may be used to unlock the catch in an emergency. The releasing member 35 has a hook shaped end 36a which may be inserted through an aperture 38 in handle 35 and engaged with a recess or hole 51 a in the chamfered end 51 of the shaft 49 in order to draw the shaft 49 forwards, hence withdrawing limb 58' of member 58 from the housing 43, via hole 59, to unlock the catch. A short guide tube (not shown) may be fitted to guide the hooked end 36a into position.

It will be appreciated that when handle 57 has been pulled to withdraw shaft 49, whereby the limb 58' enters aperture 59 in housing 43, it would would not then be possible to slam the door shut from the other side (i.e. on which handle 53 is situated), thereby preventing access from that side, because the limb 58' then acts as a stop which would prevent movement of the slide 41 against its return spring 45.

Claims (11)

1. A releasable fastener comprising a spring-loaded catch and a shaft which provides attachment for a handle, the shaft being slidable into a position to inhibit operation of the catch from at least one side.

2. A releasable fastener according to claim 1 wherein locking means are provided to inhibit operation of the catch when the shaft is in said position.

3. A releasable fastener according to claim 2 wherein the locking element is a camming member.

4. A releasable fastener according to claim 3 wherein a push rod is moved by the camming member, when the shaft is slid into said position, so as to inhibit operation of the catch.

5. A releasable fastener according to any one of the preceding claims wherein the spring-loaded catch is a ball catch.

6. A releasable fastener according to claim 2 wherein the locking element is a stop.

7. A releasable fastener according to claim 6 wherein the catch is of a type which is normally operated by rotating the shaft, the catch including or forming part of a slide and the movement of the slide being restricted when the shaft is in said position.

8. A releasable fastener according to any one of the preceding claims including detent means which normally acts on the shaft to prevent the shaft from sliding into the position in which it inhibits operation of the catch unless sufficient force is applied to the shaft to release the detent means.

9. An openable member having fitted thereto a releasable fastener in accordance with any one of the preceding claims, the arrangement being such that the shaft is pulled to open the openable member and it is pushed to close the openable member.

1 0. An openable member having fitted thereto a releasable fastener according to claim 7, the slidable movement of the shaft being sufficient for operably disengaging one end of the shaft from a handle fitted to the operable member.

11. An openable member according to claim 10 wherein the shaft projects through a handle fitted to the operable member.

1 2. An openable member according to any one of claims 9-11 in which the/or a handle fitted to the openable member has an aperture therethrough for receiving a releasing member for causing slidable movement of the shaft so as to release it from its locking position.

1 3. A releasable fastener substantially as herein described with reference to Figs. 1 and 2 of the accompanying drawings.

1 4. A releasable fastener substantially as herein described with reference to Fig. 3 of the accompanying drawings.