GB2348239A

GB2348239A - Strike plate with resilient means to prevent unauthorised access

Info

Publication number: GB2348239A
Application number: GB9826136A
Authority: GB
Inventors: Enda Keaveney
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-11-27
Filing date: 1998-11-27
Publication date: 2000-09-27
Also published as: AU1396500A; GB9826136D0; WO2000032895A1

Abstract

A strike plate unit 10 for use with a lock bolt comprises a plate 15, the plate 15 defining an aperture 18 through which the bolt may pass; the unit 10 also comprising a recess 20 which receives the bolt and resilient means in the form of a block 19 interposed between the recess 20 and the plate 15. The resilient means may be an elastomeric rubber of shore hardness between 35A and 50D. The resilient means is adapted to resist movement of the bolt should an attempt be made to force the lock. Preferably the unit 10 further contains a metal tube 21 within the recess 20 for receiving the bolt. Optionally the plate may have a flange (26, figure 7) and a chamfered edge to the aperture (28, figure 7).

Description

20348239 DESCRIPTION OF INVENTION "'IMPROVEMENTS IN OR RELATING TO A LOCK

PLATE UNIT" THE PRESENT INVENTION relates to a lock plate unit, and more particularly relates to a lock plate unit for use with a door lock.

A lock plate, for use with a door lock, is typically mounted in or on the door frame which supports the door carrying the lock. The lock plate is provided with an aperture or recess adapted to receive the bolt of the lock.

A typical lock plate comprises a simple metal plate defining the aperture, and when a lock plate of this type is used, a recess dimensioned to receive the bolt is chiselled in the door frame and the lock plate is then mounted in position over the recess with the aperture in the lock plate communicating with the recess.

When an attempt is made, for example by a burglar, to gain access through a locked door, the door is often kicked or "shouldered" with the intention of breaking the door frame in the area surrounding the lock plate, so that the bolt of the lock is freed from the door frame, permitting the door to be opened.

The present invention seeks to provide an improved lock plate unit.

According to this invention there is provided a lock plate unit for use with a lock having a bolt, the lock plate unit having a plate element and means to secure the plate element to a door frame, the plate element defining an aperture through which the bolt may pass, the unit also defining a recess adapted to receive the bolt after it has passed through said aperture, there being resilient means interposed between said recess and the plate, adapted resiliently to resist movement of the bolt, while in the recess, relative to the plate.

Preferably the recess is defined by a metal tube.

Conveniently the recess is defined in a block of resilient material, the block of resilient material extending from the rear side of the said plate.

Advantageously part of the one face of the block of the resilient material extends through the said aperture formed in the said plate so that the said part of the said face of a block of material is substantially flush with the front face of the said plate.

Alternatively the rear face of the plate carries a housing, the housing containing said resilient means.

Advantageously a tube is provided within the housing substantially aligned with the aperture formed in the plate, the space between the tube and the housing being substantially filled with a resilient material.

Conveniently one side edge of the aperture and an adjacent wall of the tube are chanifered.

3 Preferably the resilient material is an elastomeric material having a Shore hardness of between 35A and 50D.

In order that the invention may be more readily understood, and so that further features thereof -may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE I is a perspective view of a door provided with a lock and having a door frame provided with a lock plate unit in accordance with the invention, FIGURE 2 is a side view of the edge of the door frame before the lock plate unit is mounted in position, FIGURE 3 is a sectional view of the door frame taken on the line III-111 of Figure 2, FIGURE 4 is a front view of a lock plate unit in accordance with the invention, FIGURE 5 is a view from beneath the lock plate unit of Figure 4, FIGURE 6 is a side view of the lock plate unit of Figure 4, and FIGURE 7 is a sectional view of an alternative form of lock plate unit in accordance with the invention.

4 Referring initially to Figure I of the accompanying drawings, a door I is hingedly connected to a door frame 2. The door I carries a lock 3. In this embodiment the lock 3 incorporates a latch bolt 4. The latch bolt 4 can be retracted by use of a handle 5, but may equally be locked in the extended position by means of a key inserted through keyhole 6.

The door frame 2 carries a lock plate unit 10 in accordance with the invention adapted to co-operate with the latch bolt 4 of the lock.

Referring now to Figures 2 and 3, a vertical part of the door frame 2 is provided with a relatively deep horizontal recess I I of rectangular form substantially centrally located in an inner face of the door frame. A shallower recess 12 surrounds the deep recess 11, the shallow recess 12 having a greater vertical height than the recess 11, and having a greater transverse width than the recess 11. The recess 12 is of generally rectangular form. However, the recess 12 has a portion 13, located to one side of the deep recess 11, which extends to the edge of the door frame 2. The recess is provided with bores 14 adapted to receive screws. A recess of this type is conventional in the mounting of a lock plate.

Referring now to Figure 4, a lock plate unit 10 in accordance with the invention is illustrated. The lock plate unit 10 comprises a face plate 15 formed of an appropriate metal. The face plate 15 is of generally rectangular form, and has a size corresponding to the size of the recess 12. One side edge of the face plate is provided, in a central region thereof, with a laterally extending flange 16, the flange being angled slightly, as can be seen from Figure 5, so that it does not lie in the same plane as the rest of the face plate 15.

I I The face plate 15 is provided with screw holes 17, substantially aligned with the bores 14 in the recess 12, adapted to receive screws to fasten the face plate in position.

The face plate is provided with a substantially centrally located rectangular aperture 18, the size of the aperture 18 being slightly less than the size of the deep recess 11.

The flange 16 has a vertical extent which is substantially greater than the vertical extent of the aperture 18 and consequently the face plate is very strong.

Mounted to the rear of the face plate 18 is a block 19 of resilient material. The block 19 may have such a configuration that the overall size of the block is slightly greater than the size of the aperture 18. The block may be mounted in position so that part of the front face of the block is substantially flush with the front face of the face plate 15. The block may be adhered in position.

The block 19 may be made of rubber having a Shore hardness of between 35A and 50D, How-ever, other resilient materials may be used.

A rectangular horizontal recess 20 is formed "in the part of the resilient block 19 visible through the aperture 18 formed in the face plate 15. The recess 20 may comprise a passage that extends completely through the block 19. Received within the recess 20, as a slidable fit, or as a friction fit, is a short rectangular tube 21 formed of an appropriate metal, which itself defines a recess aligned with the recess 20.

6 It is to be appreciated that the block 19 is dimensioned to be received within the recess I I formed in the door frame 2, when the face plate 15 is received within the recess 12. The flange 16 of the face plate is accommodated within the cut-away region 13 of the door frame 2.

It is to be appreciated that the door lock may be utilised in the conventional manner, but when the latch bolt is in the locked condition, the bolt is received within the metal tube 21 which is itself mounted within the resilient block 19. Thus, the resistant block is interposed between the recess defined within the tube 21 and the force plate 15. Thus, should any attempt be made to force the door, by kicking or "shouldering" the door, the force applied to the door will be transferred to the latch bolt, and from the latch bolt to the metal tube 21, and from the metal tube 21 to the resilient block 19. The resilient block 19 will deform, thus absorbing the force and minimising the risk of damage being effected to the door frame.

It is to be appreciated that in the embodiment of Figures 4 to 6, is most desirable for the recess I I to receive the resilient block 19 in a snug manner, since if the recess I I is over-sized there is a risk that if a very substantial force is applied to the door, the resilient block 19 may be separated from the face plate 15.

Figure 7 illustrates a modified embodiment of the invention. In this embodiment of the invention a face plate 25 is provided, at one side thereof, with a laterally extending downwardly inclined flange 26 corresponding to the flange 16 of the embodiment of Figures 4 to 6. The face plate defines a central aperture 27, which is somewhat smaller than the aperture 18 of the embodiment of Figures 4 to 6. The side of the aperture 28, which is adjacent the flange 26 is chainfered.

7 Secured to the rear face of the face plate 25 is a housing 29. Contained within the housing is a rectangular tube 30 having two opposed side walls 31,32 which are visible in Figure 7. The tube is substantially aligned with the aperture 27, and the upper edge of the side wall 32, which is located closest to the flange 26, is chamfered 33. The chamfered upper edge of the side wall 32 is substantially in alignment with the chainfered edge 28 of the aperture 27. The tube 30 is mounted in position within the housing by one or more resilient elements 34,35 which substantially fill the space between the tube 30 and the adjacent side walls of the housing. The tube 30 is not in contact with the housing 29, and is not in contact with the face plate 25.

The tube 30 defines a recess adapted to receive the bolt of a lock, and the resilient elements 34,35 are effectively interposed between the recess and the face plate 25.

It is to be appreciated that in use of the lock plate unit of Figure 7, if the latch bolt is permanently biased towards the lock position, then as the door is closed the latch bolt will -engage the inclined flange 26, and will be moved towards the retracted position as the door closes. An edge portion of the bolt will move up the inclined flange 26 and across the part of the face plate 25 between that flange and the aperture 27. The edge of the latch bolt will then ride down the chainfered side of the aperture 28, and the chamfered edge 32 of the tube 30 so that the bolt is received within the recess defined within the tube 30. The latch bolt thus does not run across any exposed face of the resilient element 34. In the event that an attempt is made to force the door incorporating the lock, any force applied to the door will be transferred, from the latch bolt to the tube 30, causing the resilient material 34,35 to be compressed between the tube and the housing 29. It is to be appreciated that in 8 this embodiment of the invention, whilst it is desirable that the recess I I should be dimensioned to receive the housing 29, if the recess I I is over-sized, the desired effect will still be achieved.

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Claims

9 CLAIMS:

1. A lock plate unit for use with a lock having a bolt, the lock plate unit having a plate element and means to secure the plate element to a door frame, the plate element defining an aperture through which the bolt may pass, the unit also defining a recess adapted to receive the bolt after it has passed through said aperture, there being resilient means interposed between said recess and the plate, adapted resiliently to resist movement of the bolt, while "in the recess, relative to the plate.

2. A lock plate unit according to Claim I wherein the recess is defined by a metal tube.

3. A lock plate unit according to Claim I or Claim 2 wherein the recess is defined in a block of resilient material, the block of resilient material extending from the rear side of the said plate.

4. A lock plate unit according to Claim 3 wherein part of one face of the block of the resilient material extends through the said aperture formed in the said plate so that the said part of the said face of a block of material is substantially flush with the front face of the said plate.

5. A lock plate according to any one of Claims I or 2 wherein the rear face of the plate carries a housing, the housing containing said resilient means.

6. A lock plate unit according to Claim 5 wherein a tube is provided within the housing substantially aligned with the aperture formed in the plate, the space between the tube and the housing being substantially filled with a resilient material.

7. A lock plate unit according to Claim 6 wherein one side edge of the aperture and an adjacent wall of the tube are chanifered.

8. A lock plate unit according to Claim 3 or Claim 5, or Claim 6 wherein the resilient material is an elastomeric material having a Shore hardness of between 35A and 50D.

9. A lock plate unit substantially as herein described with reference to and as shown in the accompanying drawings.

10. Any novel feature or combination of features disclosed herein.

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