GB2290574A - Improvements in securing doors - Google Patents

Abstract

A door securing member, such as a door keeper 10 or a door hinge 40 includes upper and lower faces 28, 29; 48, 50 which lie at an acute angle to the direction of application of a door opening force. On application of a door opening force the force transferred to the door lamb includes a lateral component and distributes the load on the inclined faces to increase the failure load of the door frame. The faces 48, 50 of the hinge 40 may be provided with teeth and keeper 10 may have additional energy absorbing means such as springs 26, 27. <IMAGE>

Description

IMPROVEMENTS IN SECURING DOORS This invention relates to improvements in securing doors, and in particular relates to a door keeper and a door hinge.

One of the most common means of gaining unauthorised entry to homes or premises involves the forcing of doors, for example, by means of kicking or use of sledgehammers or crowbars. Often, the door will open after failure of the wooden door jamb, which permits movement of the door keeper sufficient to allow release of the lock latch or bolt.

The likelihood of a door jamb splitting in these circumstances may be minimised by fixing a metal plate over the inside face of the door frame. However, many householders may find such a plate aesthetically obtrusive and unattractive.

It is among the objects of this invention to obviate or mitigate these disadvantages.

According to one aspect of the present invention there is provided a door keeper for location in a door jamb, the keeper comprising a body member defining means for receiving a latch or bolt and means for transferring forces to the door jamb including one or more faces inclined at an acute angle to the direction of application of a door opening force to the door keeper.

According to another aspect of the present invention there is provided a door hinge for mounting on a door jamb, the hinge including two pivotally connected members, at least one of said members having means for transferring forces to the door jamb including one or more faces inclined at an acute angle to the direction of application of a door opening force to the hinge.

Although reference will be made primarily to a door keeper and door hinge, the invention is not limited to use in conjunction with doors and could, for example, be used in conjunction with a window or hatch.

In use, it is believed that the keeper and hinge transfer a significant force component to the door jamb laterally of the applied force and which force component tends to compress the door jamb along its length. This is particularly significant when the keeper is fitted in a wooden door jamb, in which the grain of the wood extends along the length of the jamb: the jamb will withstand forces applied along its length, along the grain, more readily than forces applied across its width, and across the grain.

Preferably, the door keeper body and the hinge member are each wedge-shaped and, in use, a corresponding recess is provided in the door jamb. It is believed that the resulting tapered member alters the conditions for crack propagation and increases the load required to fracture the jamb. The inclined faces reduce the tensile stress acting transversely to the grain of the wood along the delamination plane, by distributing load on the inclined faces, and hence increases the failure load of the door frame.

The inclined faces may be smooth, toothed, splined or stepped, concave or convex. The inclined faces may further carry energy absorbing means, such as resilient pads The keeper body or hinge member may be fixed to the door jamb using screws, bolts or other fasteners which pass through suitable apertures. The apertures may be in the form of slots, which will permit a degree of movement of the keeper body or hinge member relative to the fasteners. Most preferably, this feature is provided in combination with energy absorbing means on the inclined faces.

The door keeper body or hinge member may be formed of deformable energy absorbing material such as rubber, spring steel or composite which has the ability to deform and then reform under mechanical loading. The door keeper body or hinge member may include portions adapted to permanently deform under mechanical loading.

Preferably also, the door keeper includes a resiliently mounted latch or bolt engaging member. Thus, if a sudden force is applied to the door, the member may deform, reducing the impulse of the applied force and thus minimising the likelihood of the door being forced open.

Conveniently, the bolt engaging member may be mounted to the body via springs. Energy absorbing means, such as a rubber pad, may also be provided.

Another aspect of the invention relates to a fixing member or fastener such as a nail, which is triangular or trapezoidal in section.

These and other aspects of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a part cut-away side view of a door keeper in accordance with a preferred embodiment of the present invention, shown fitted in a wooden door jamb; and Figure 2 is a view of a part of a hinge in accordance with a further embodiment of the present invention shown fitted in a wooden door jamb.

Reference is first made to Figure 1 of the drawings, showing a door keeper 10 fitted in a wooden door jamb. The keeper has a generally trapezoidal or wedge-shaped hollow body 14 and is located in a corresponding recess 16 cut into the door jamb 12. The inclined faces carry resilient stiff rubber pads 17. Positioned within the body 14, and extending across an opening 18 in the body 14, is a door bolt engaging member 20 which defines an eye 22 for receiving the door bolt 24. The member 20 is mounted to the body 14 via stiff springs 26, 27.

The keeper 10 is secured to the door jamb 12 using screws 28 which pass through slots 30 in the keeper body into the jamb 12.

If an attempt is made to force the door open, the force F applied to the door, and transferred to the keeper 10 by the bolt 24, is generally perpendicular to the door jamb 12, and across the grain of the wood forming the jamb.

However, the inclined upper and lower faces 28, 29 of the body 14 result in the resultant force applied to the walls of the recess 16 including components C perpendicular to the door opening force F. Thus, for the keeper 10 to be displaced relative to the door jamb 12 requires compression of the door jamb, along the grain of the wood. This requires a far greater force than would be necessary to cause the wood to split, and the keeper 10 to be displaced, if the force transferred to the jamb was acting solely across the wood grain.

The mounting of the member 20 on springs 26, 27 leads to a limited degree of movement of the member relative to the body 14 on application of a sudden sharp force to the door, such as would result from the door being struck by a sledgehammer. This reduces the impulse on the door jamb, thus reducing the likelihood of the jamb failing. The provision of the rubber pads 17 and the slots 30 for receiving the fixing screws 28 also permits a degree of shock absorbing movement of the keeper body relative to the jamb 12.

Reference is now made to Figure 2 of the drawings, which illustrates a hinge 40 in accordance with another embodiment of the invention. The hinge is formed of two hinge plates 42, 44, and the plate to be secured to the supporting jamb 46 is of trapezoidal form, with inclined upper and lower faces 48, 50. Thus, the hinge plate 42 transfers applied mechanical loads to the jamb 46 in a similar manner to the keeper described above. In addition, the faces 48, 50 are toothed, to bite into the abutting faces of the recess cut in the jamb to receive the hinge.

From the above description it will be apparent that the above-described embodiments provide a simple means for improving the security of a door.

It will also be clear to those of skill in the art that the above-described embodiments are only examples of the invention, and that various modifications and improvements may be made thereto without departing from the scope of the invention.

Claims (12)

1. A door keeper for location in a door jamb, the keeper comprising a body member defining means for receiving a latch or bolt and means for transferring forces to the door jamb including one or more faces inclined at an acute angle to the direction of application of a door opening force to the door keeper.

2. A door hinge for mounting on a door jamb, the hinge including two pivotally connected members, at least one of said members having means for transferring forces to the door jamb including one or more faces inclined at an acute angle to the direction of application of a door opening force to the hinge.

3. The invention of claim 1 or claim 2, wherein the member defines upper and lower faces inclined at an acute angle to the direction of application of a door opening force.

4. The invention of claim 3, wherein the member is generally trapezoidal.

5. The invention of any of claims 1 to 4, wherein the inclined faces are toothed.

6. The invention of any of claims 1 to 5, wherein the inclined faces carry energy absorbing means.

7. The invention of any of the preceding claims wherein the member is fixed to the door jamb using fasteners which pass through slots extending parallel to the direction of application of a door opening force.

8. The invention of any of the preceding claims wherein the member is formed of deformable energy absorbing material.

9. The invention of any of the preceding claims wherein the member includes one or more portions adapted to permanently deform under mechanical loading.

10. The door keeper of claim 1 or claims 3 to 9 when dependent on claim 1 further including a resilient mounting latch or bolt engaging member.

11. The door keeper substantially as described herein and as illustrated in Figure 1 of the accompanying drawings.

12. The hinge substantially as described herein and as illustrated in Figure 2 of the accompanying drawings.