GB2327233A - Vent security device with articulated projection - Google Patents

Abstract

A vent security device 21 comprises a mounting plate 23 for attachment to a first part of a window frame 25 and a tapered projection 29 for engaging a second part of the window frame 39, wherein the projection 29 and the mounting plate 23 are articulated. A leaf spring (not shown) acts between the projection and mounting plate so that the projection approaches an aperture 49 in a keep 37 at the correct angle to facilitate entry. The aperture has a chamfered edge 51 for receiving the projection. As a result, the security device can be used with an egress hinge (not shown) in which the angle of approach of the moveable frame 25 towards the fixed frame 39 is severe.

Description

A SECURITY DEVICE This invention relates to security devices, and in particular to a novel form of dog bolt for a vent such as a window.

A vent, such as a window, comprises a fixed frame and a moveable frame hingedly connected to the fixed frame. The moveable frame, in the case of a window, includes a pane of glass and, in use, the moveable frame can swing from a closed position substantially parallel to the fixed frame to an open position at an angle to the fixed frame. The free edge of the moveable frame usually carries a handle or other.

locking member which, when the vent is closed, can engage the fixed frame to retain and/or lock the moveable frame to the fixed frame. Although such an arrangement provides reasonable security against intruders, improved security can be obtained by using dog bolts mounted on the moveable frame which engage the fixed frame when the vent is closed.

Since the handle on a moveable frame engages and locks the moveable frame to the fixed frame at the free edge of the moveable frame, it is often the opposite edge of the moveable frame which is attacked by an intruder, possibly with a jemmy. The intruder tries to force the jemmy between the moveable frame and the fixed frame to cause the moveable frame to separate from the fixed frame, thereby facilitating access through the vent. Hence, dog bolts have, in the past, been applied to this area of a vent, such that a dog bolt on the moveable frame engages in an aperture in the fixed frame as the moveable frame swings into its closed position relative to the fixed frame. Such dog bolts work well and provide a significant improvement in vent security.

A dog bolt is essentially a projection or spigot which extends from a surface of a moveable frame such that, as the moveable frame approaches the fixed frame during closing of the vent, the projection passes into a recess, or through an aperture, formed in the fixed frame of the vent. Although this arrangement is fine for most hinge configurations, because the angle of approach of the projection is such that it can readily enter a recess in a fixed frame, this is not necessarily the case when a vent employs an egress hinge because the angle of approach is too severe and the projection clashes with the fixed frame as it tries to enter the recess.

An egress hinge is a hinge which allows a moveable vent to open to a position substantially perpendicular to the plane of its fixed frame, with the moveable vent close to one side of the fixed frame, such that a large opening is provided for egress. A hinge of this kind shown in Figure 1 of the accompanying drawings.

With reference to Figure 1 of the drawings, an egress hinge 1 comprises a C-sectioned support track 3 which accommodates two sliders 5,7 which can move along the support track 3. A vent arm 9 for supporting a moveable frame (not shown) is joined to the sliders 5,7 by a plurality of links and struts 11 such that the vent arm 9 can move from a closed position substantially parallel to the support track 3 to an open position (as shown in Figure 1) at approximately 900 to the support track 3 adjacent one end of the support track 3. Movement of the vent arm 9 in this way is allowed because the first slider 5 moves along the support track 3.

As shown in Figure 1, the vent arm 9, when in its open position, can be moved relative to the support track 3 by releasing a locking device 13. This allows the second slider 7 to slide along the support track 3 to a position shown in phantom lines in Figure 1. Cleaning of the outside of the vent can then be undertaken.

The motion of a nose portion 15 of the vent arm 9 is also shown in Figure 1 of the drawings, in chain lines. As will be appreciated, this motion results in a severe angle of approach of the nose portion 15 to an end cap 17 mounted on the support track 3. Similarly, since a vent frame is mounted on the vent arm 9, the angle of approach of the vent frame is the same as that of the end point 15 of the vent arm 9. Accordingly, a dog bolt projection mounted on the vent frame moves in a similar fashion and, if a prior art dog bolt is used, clashing will occur to prevent the dog bolt projection from entering a recess or aperture in the fixed frame of the vent.

With the foregoing in mind, the present invention aims to improve upon known prior art dog bolts by providing a security device of a similar type which can be used with egress hinges.

According to the present invention, there is provided a security device comprising a mounting plate for attachment to a first part of a vent and a projection for engaging a second part of the vent, wherein the projection and mounting plate are articulated. As a result, engagement of a second part of a vent by the projection, in use, is facilitated.

Furthermore, the angle of approach of a moveable frame of a vent relative to a fixed frame becomes less of a problem.

In a particular embodiment, the projection is carried by a support plate which forms a hinge with the mounting plate. Added strength is thereby provided.

Preferably the projection is biased away from the mounting plate. As a result, during closing of the vent, pressure is applied on the projection which acts against the biasing means to move the projection relative to the mounting plate.

A spring may act between the projection and the mounting plate. Such a spring may be a leaf spring, although any other appropriate biasing means could alternatively be used.

In one embodiment, the mounting plate and/or the support plate are substantially rectangular. The projection may be substantially circular in cross-section, possibly with a tapered free end, although this is not essential.

Alternatively, the projection may have a rectangular section, possibly with a curved end, or even be shaped like a banana.

A keep is also preferably provided for mounting on the second part of a vent, in use. Accordingly, this can provide additional reinforcement because the projection will engage in this keep when the vent is closed.

The keep and/or the mounting plate may be substantially planar, thereby allowing each component to be accommodated in a recess or groove in an extruded moulding of a frame.

The keep may define an aperture having a chamferred, curved or radiused edge for receiving the projection, during use. The chamfered edge may apply forces to the projection which result in the projection being moved against the biasing means during closing of a vent.

The security device is preferably manufactured from metal, possibly die-cast. However, in theory, the security device could be made from other materials, such as plastics materials, which could allow the device to be manufactured in one piece with an in-built hinge.

According to another aspect of the present invention, there is provided a vent system comprising a fixed frame, a moveable frame and a security device as claimed hereinafter.

In such a system, the security device (or articulated dog bolt) is preferably mounted on the movable frame and engages an aperture in the fixed frame when the vent is closed.

Further, the security device preferably articulates during closing of the vent such that, when the vent is closed, the axis of the projection is substantially parallel to the plane of the vent. As a result, improved security is provided against intruders.

A specific embodiment of the present invention is now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of an egress hinge of known type; Figure 2 is a perspective view of part of a vent showing a security device according to the present invention in position during closing of the vent; Figure 3A is a perspective view of an articulated security device according to the present invention; Figure 3B is a sectional view in the direction B-B of Figure 3A; Figure 3C is a side sectional view in the direction CC of Figure 3B; Figure 4A is a perspective view of a keep for use with a security device according to the present invention; Figure 4B is a sectional view in the direction BB of Figure 4A; and Figure 4C is a sectional view in the direction CC of Figure 4A.

An embodiment of the present invention will now be described with reference to Figures 2-4 of the accompanying drawings. In particular, a security device 21 comprises a mounting plate 23 for attachment to a moveable frame 25 of a vent (not shown). Screws or other appropriate fixing devices are used to mount the plate 23 in a recess formed in the moveable frame 25. A support plate 27 carrying a projection 29 is hingedly connected to the mounting plate 23 and is biased away from the mounting plate 23 by means of a leaf spring 31 attached to the mounting plate 23 by means of a pin 33 (cf. Figures 3B and 3C). The projection 29 has a tapered end 35 for entry into a keep 37 mounted on a fixed frame 39 of the vent. Once again, the keep 37 can be fixed in a recess 41 in the fixed frame 39 by means of screws 43 or other appropriate fastening devices.

The support plate 27 includes two apertures 45 through which access can be obtained to the fastening devices (not shown) which retain the mounting plate 23 on the moveable frame 25.

The support plate 27, as mentioned above, is hingedly connected via a hinge 47 to the mounting plate 23. The hinge 47 is on the outside of the mounting plate 23 such that, due to the leaf spring 31, the projection 29 is biased towards the keep 37. This means that the projection 29 passes through an aperture 49 in the keep 37 earlier than would be the case with a normal dog bolt projection. The hinge 47 also includes a stop which defines the maximum angle between the support plate 27 and the mounting plate 23, which angle can be predetermined for a particular vent system.

As the moveable frame 25 approaches the fixed frame 39, the projection 29 enters the keep 37 and bears against a chamferred edge 51 of the aperture 49. Further closing of the vent causes the chamferred surface 51 to apply force to the projection 29 which causes the support plate 27 to articulate relative to the mounting plate 23. When the vent is fully closed, the support plate 27 abuts the keep 37 with the projection 29 fully engaged in the fixed frame 39. In this orientation, the support plate 27 is substantially parallel to the mounting plate 23 and the leaf spring 31 is fully compressed.

As can be seen more clearly in Figure 3, the leaf spring 31 is accommodated in a groove formed in the mounting plate 23. During re-opening of the vent, the leaf spring 31 once again drives the support plate 27 and projection 29 away from the mounting plate 23.

As will be appreciated from the foregoing, the present invention provides a security device which is a marked improvement over the prior art devices, because it can also be used with egress hinges to provide additional security.

It will of course be understood that the present invention has been described above purely by way of example, and that modifications of detail can be made within the scope of the invention.

Claims (18)

1. A security device comprising a mounting plate for attachment to a first part of a vent and a projection for engaging a second part of the vent, wherein the projection and the mounting plate are articulated.

2. A device as claimed in claim 1, wherein the projection is carried by a support plate which is hingedly connected to the mounting plate.

3. A device as claimed in claim 2, wherein the mounting plate and/or the support plate are substantially rectangular.

4. A device as claimed in any preceding claim, wherein the projection is biased away from the mounting plate.

5. A device as claimed in claim 4, wherein a spring acts between the projection and the mounting plate.

6. A device as claimed in claim 5, wherein the spring is a leaf spring.

7. A device as claimed in any preceding claim, wherein the projection is substantially circular in cross-section.

8. A device as claimed in any preceding claim, wherein the free end of the projection is tapered.

9. A device as claimed in any preceding claim, further comprising a keep which, in use, receives the projection.

10. A device as claimed in claim 9, wherein the keep and/or the mounting plate are substantially planar.

11. A device as claimed in claim 9 or claim 10, wherein the keep defines an aperture having a chamfered edge for receiving the projection, during use.

12. A device as claimed in any preceding claim, which is manufactured from metal.

13. A device as claimed in claim 12, wherein the device is die-cast.

14. A security device substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

15. A vent system comprising a fixed frame, a moveable vent and a security device as claimed in any preceding claim.

16. A system as claimed in claim 15, wherein the security device is mounted on the moveable vent and engages an aperture in the fixed frame when the vent is closed.

17. A system as claimed in claim 15 or claim 16, wherein the security device articulates during closing of the vent such that, when the vent is closed, the axis of the projection is substantially parallel to the plane of the vent.

18. A vent system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.