GB2180586A

GB2180586A - Security device for doors and windows

Info

Publication number: GB2180586A
Application number: GB08522657A
Authority: GB
Inventors: Nigel Philip Shenton
Original assignee: Hardware and Systems Patents Ltd
Current assignee: Hardware and Systems Patents Ltd
Priority date: 1985-09-13
Filing date: 1985-09-13
Publication date: 1987-04-01
Also published as: GB2180586B; GB8522657D0

Abstract

A bolt 2 which is slidably mounted in a casing is biassed into a retracted position by a spring 3 and is moved into an advanced position by a lever 11 pivotally mounted in the casing. The lever 11 has a cam surface 15 engageable with the bolt 2 and the cam surface 15 provides a rising cam action to advance the bolt 2 terminating in an over-centre action to retain positively the bolt 2 in the advanced position. In use, the casing 1 is mounted on one of a fixed frame and a closure member (the door or sash) and the bolt 2 is engageable with an opening associated with the other of the fixed frame and closure member to secure the closure member relative to the fixed frame. <IMAGE>

Description

SPECIFICATION Security device This invention relates to security devices for doors or windows.

Security devices for doors or windows com- prising a fixed frame and a closure member are known in which a bolt mounted on one of the fixed frame and closure member is engageable in an opening in the other of the fixed frame and closure member to secure the closure member in the closed position.

A disadvantage of certain known devices of this type is that it is possible to effect forced entry by drilling the closure member from the outside to gain access to the projecting end of the bolt received in the opening whereupon the bolt may be retracted to disengage the opening thereby releasing the closure member for opening movement relative to the fixed frame.

It is known to provide additional locking means to secure the bolt in the advanced position but such locking means add significantly to the manufacturing costs. Also, the user may advance the bolt but forget to operate the locking means so that forced entry may still be effected as aforedescribed.

It is an object of the present invention to provide a security device which avoids the problems and disadvantages aforedescribed.

According to the present invention there is provided a security device comprising a casing, a bolt slidably mounted in the casing, spring means biassing the bolt to a retracted position and an actuator pivotally mounted in the casing and manually operable to move the bolt to an advanced position and to retain the bolt in the advanced position against the biassing of the spring means.

By the instant invention, the bolt is advanced and retained in the advanced position by operation of the actuator. In this way additional locking means to secure the bolt in the advanced position is not required.

Preferably the actuator comprises a lever pivotally mounted at one end in the casing and extending outwards through an opening in the casing to permit manual operation of the actuator.

The pivotted end of the lever is shaped to form a cam having a cam surface engageable with one end of the bolt. Advantageously, the cam surface provides a rising cam action on pivotal movement of the lever in one sense to advance the bolt terminating in an overcentre action to positively retain the bolt in the advanced position.

Preferably the pivot axis of the lever lies on the longitudinal axis of the bolt whereby any force applied to the projecting end of the bolt to retract the bolt tends to pivot the bolt in the same sense, i.e. in the direction in which the bolt is advanced.

The bolt is automatically retracted under the biassing of the spring means on pivotting the lever in the sense opposed to that in which the bolt is advanced.

Conveniently, the casing is formed in two halves which are similar to each other and provided with formations which on assembly define a recess for locating and guiding the bolt and a pivot pin for mounting the lever.

Preferably the pivot pin is provided at one end of the recess and the spring means comprises a spring encircling the bolt and acting between the other end of the recess remote from the pivot pin and an enlarged head on the bolt. The cam surface engages the bolt head and the recess wall is diametrically slotted to accommodate pivotal movement of the cam.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of part of a sliding frame assembly having a security device according to the present invention mounted on a fixed frame member; Figure 2 is a side view of the security device shown in Fig. 1 with one half of the casing removed for clarity, the bolt being shown in the retacted position; and Figure 3 is a side view, similar to Fig. 2, showing the bolt in the advanced position.

Referring to the accompanying drawings, there is shown a security device comprising a casing 1, a cylindrical bolt 2 slidably mounted in the casing 1, a spring 3 biassing the bolt 2 to a retracted position (Fig. 2) and an actuator 4 pivotally mounted in the casing 1 and manually operable to move the bolt 2 to an advanced position (Fig. 3) and to retain the bolt 2 in the advanced position against the biassing of spring 3.

The casing 1 is constituted by two similar halves 5,5', each of which is of semi-circular shape in side view. The casing halves 5,5' are formed with opposed complementary formations which, on assembly, define a cylindrical recess 6 for the bolt 2 and a pivot pin 7 for the actuator 4. In addition, one half 5 has a pair of spaced apart cylindrical bosses 8 which are an interference fit in aligned holes (not shown) in the other half 5' to secure the two halves together on assembly and provide through bores 9 for screws 10 by means of which the device is mounted in use.

The actuator 4 comprises a lever 11 which is pivotally mounted at one end on the pivot pin 7 and extends outwards through an elongate opening 12 formed in the arcuate wall portion 13 of the casing 1 by opposed recesses in the halves 5,5' to permit manual operation of the actuator 4. The ends of the opening 12 provide end stops to limit pivotal movement of the lever 11 between the extreme positions shown in Figs. 2 and 3.

The pivot pin 7 is centred on the longitudi nal axis of the bolt 2 at one end of the recess 6 and the pivotted end of the lever 11 is flattened to form a cam 14 the marginal edge of which provides a cam surface 15 engageable with an enlarged head 16 at one end of the bolt 2. The other end of the bolt 2 projects outwards through a hole 17 in the flat wall portion 18 of the casing 1 at the other end of the recess 6. The spring 3 encircles the bolt 2 and acts between said other end of the recess 6 remote from the pivot pin 7 and the bolt head 16 to biass the bolt 2 towards the cam surface 15.

The cam surface 15 has three distinct parts 19,20,21 of varying radius about the centre of the pivot pin 7 and the recess wall is diametrically slotted as shown at 22 to accommodate pivotal movement of the cam 14. The first and second cam surface parts 19,20 are shaped to provide a rising cam action on pivotting the lever 11 in a clockwise direction from the position shown in Fig. 2 to advance the bolt 2 against the biassing of the spring 3, and the second and third cam surface parts 20,21 are shaped to provide an over-centre action to positively retain the bolt 2 in the advanced position shown in Fig. 3. The bolt 2 is automatically returned to the retracted position under the biassing of spring 3 on pivotting the lever 11 in an anticlockwise direction from the position shown in Fig. 3.

Referring now to Fig. 1, there is shown a sliding frame assembly comprising a fixed frame 23 and a closure member 24, for example a door or sash, slidably mounted for opening/closing movement relative to the fixed frame 23. The security device is mounted on the side edge of the fixed frame 23 adjacent to the bottom with the flat wall portion 18 facing the closure member 24 and, a cylindrical blind bore 25 is drilled in the frame of the closure member 24 at a position directly opposite the bolt 2 in the closed position of the closure member 24. To secure the closure member 24 in the closed position, the lever 11 is pivotted to move the bolt 2 to the advanced position in which it is received in the bore 25.

As will be appreciated, by the provision of cam 14 having an over-centre action and the location of the pivot pin 7 on the longitudinal axis of the bolt 2, any attempt to retract the bolt 2 from the advanced position shown in Fig. 3 by striking the projecting end of the bolt 2 in the direction of arrow A will tend to pivot the lever 11 in the clockwise direction and be resisted by the engagement of the lever 11 with the end of the opening 12. As a result, the bolt 2 is positively retained in the advanced position and forced entry by drilling the frame of the closure member 24 from the outside to obtain access to the projecting end of the bolt 2 received in the bore 25 is precluded.

A further advantage of such positive retention of the bolt 2 in the advanced position is that additional locking means to secure the bolt 2 in the advanced position can be dispensed with.

Yet a further advantage is that lever 11 may be hand or foot operated which is of particular benefit, especially for elderly, handicapped or disabled persons, when the device is mounted at floor level.

In addition to the bore for receiving the bolt to secure the closure member in the closed position, one or more additional bores may be provided at spaced apart positions to permit the closure member to be secured in a partially open position(s) for ventilation purposes, for example a night ventilation position may be provided. The or each bore may be drilled directly in the frame of the closure member as above-described or a keeper having an appropriate number of bores formed therein may be provided for attachment to the closure member.

The invention is not limited to the embodiment above-described, which may be modified in a number of ways. For example, the bolt may be of circular, rectangular, polygonal or any other suitable cross-section.

The lever cam may be of any profile which advances the bolt and provides an over-centre action to retain positively the bolt in the advanced position.

The shape of the casing may be altered to suit the dimensions of the available space for mounting the device in any given application and, the device may be mounted either on the fixed frame as above-described or on the closure member.

Finally, although the invention has been described with reference to a sliding door or window frame assembly, it will be understood that the device may be used with door or window frame assemblies in which the closure member is mounted for hinged or pivotal movement relative to the fixed frame.

Claims

1. A security device comprising a casing, a bolt slidably mounted in the casing, spring means biassing the bolt to a retracted position and an actuator pivotally mounted in the casing and manually operable to move the bolt to an advanced position and to retain the bolt in the advaced position against the biassing of the spring means.

2. A device according to claim 1 wherein the actuator comprises a lever shaped at one end to form a cam having a cam surface engageable with one end of the bolt and extending outwards through an opening in the casing.

3. A device according to claim 2 wherein the cam surface provides a rising cam action on pivotal movement in one sense to advance the bolt terminating in an over-centre action to positively retain the bolt in the advanced posi tion.

4. A device according to claim 2 or claim 3 wherein the lever is pivotted at said one end and the pivot axis lies on the longitudinal axis of the bolt.

5. A device according to any one of claims 2 to 4 wherein the casing is formed in two halves, the halves having formations which cooperate on assembly to define a recess for locating and guiding the bolt and a pivot pin for mounting the lever.

6. A device according to claim 5 wherein the pivot pin is at one end of the recess and the spring means comprises a spring encircling the bolt and acting between the other end of the recess remote from the pivot pin and an enlarged head on the bolt.

7. A device according to Claim 1 wherein the cam surface engages the bolt head and the recess wall is diametrically slotted to accomodate pivotal of the cam.

8. A security device substantially as hereinbefore described with reference to the accompanying drawings.