GB2199610A

GB2199610A - Security bolt

Info

Publication number: GB2199610A
Application number: GB08705131A
Authority: GB
Inventors: Alan Wordsworth
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-03-14
Filing date: 1987-03-05
Publication date: 1988-07-13
Anticipated expiration: 2007-03-05
Also published as: GB8606410D0; GB2199610B; GB8705131D0

Abstract

A security bolt comprises a bolt rod (10) in a tube (2) secured to a door (3), wherein the bolt rod is urged towards it operative position by a spring (12). The bolt can be drawn from inside the door by a peg (9) and held withdrawn by turning peg (9) into horizontal portion (8) of slot (7), and from the outside by key-operated means such as a barrel lock (30) linked to the bolt rod by a tie rod (26) secured to a bent-over portion of the lock tongue (28). The tongue (28) has an over- centre position in which it rests against a stop (34) to hold the bolt in its withdrawn position. The bolt can be used in conjunction with a runner plate (14) with a recess (21) into which the bolt rod will be projected by the spring if any attempt is made to gain entry by force. <IMAGE>

Description

SECURITY BOLT This invention relates to a sliding security bolt for a door.

My published British Patent Application No.2137686A discloses a door bolt assembly comprising a bolt rod slidable along a tube carried by a backing plate which is securable to a door, a spring being provided to urge one end of the bolt rod into an operative position in which it extends from the tube. The rod is settable in two positions, in one of which the bolt rod is held inoperative against the action of the spring and in the other of which the bolt rod is urged by the spring towards its operative position to engage in an aperture, usually in the floor, to hold the door against being opened or, depending on the position of the aperture, to prevent it being opened wide enough to allow entry.

The present invention relates to a variation on the above type of bolt which enables the bolt to be operated from both sides of the door.

The present invention consists in a bolt of the type described above which also includes key-operated means on the opposite side of the door to that to which the bolt is attached whereby the bolt rod may, from the opposite side of the door, be drawn into its inoperative position against the bias of the spring or released into its operative position. Removal of the key prevents such operation by unauthorised persons.

Tho kev-nnerated means mav suitablv be in the form

of a barrel-type lock such as a Yalellock, with a rotating tongue projecting into a recess in the door behind the bolt and bent over to form a rotating lever. This can be connected by a tie rod or the like, to the bolt rod.

Preferably this connection is to a rearward projection from the bolt rod which extends through a longitudinal slot in the backplate.

The bolt assembly preferably also has means operable from the same side of the door as the bolt to block the key-operated means, so that the bolt cannot be operated from the opposite side, with or without the key.

The bolt assembly of the invention can be used with a conventional bolt hole in which the rod engages when the door is shut. There may also be provided a second bolt hole or stop positioned a short distance from the first said bolt hole (generally not more than 20cm and typically 10 to 15 cm) with which the bolt rod can engage if any attempt is made to force the door open to gain entry.

In this arrangement a pivotable cover plate may be provided for the conventional bolt hole so that the bolt rod, resting on the cover plate, does not lock the door but is ready to engage the second bolt hole or stop. Such an arrangement is disclosed in GB patent application 2137686. In the refinement of this arrangement, a cam surface extends upwardly from the bottom of the second bolt hole or stop in the direction of the main bolt hole corresponding to the shut position of the door. The door can then be pushed shut in the face of an intruder even when the bolt is released.

The cam surface pushes the bolt rod into its tube against the spring bias as the door is shut or until it rests on the cover plate or, if the main bolt hole is uncovered, until it is shot into the main bolt hole to hold the door shut.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings wherein: Figure 1 is a perspective view of one side of a bolt assembly in accordance with the bolt in its inoperative position.

Figure 2 is a vertical cross-section on the l,ne II-II of Figure 1 with the bolt in its operative position; rod Figure 3 is a plan view of a floor plate shorn in Figures 1 and 2.

Referring first to Figure 1, a security bolt comprises a bolt rod 10 slidably received in a tube 2 which is secured to a door 3 by an integral backing plate 1 and screws 4. As with a conventional door bolt, the bolt rod 10 is slidable by means of a peg 9 which projects outwardly through a bayonet slot 6. This comprises a longitudinal part 7 and a circumferential part 8. The peg 9 can be aligned with the longitudinal part 7 to allow'axial sliding of the bolt rod and with the circumferential part to allow rotation of the rod about its longitudinal axis.

A compression spring 12 is located within the tube 2, the upper end of which is closed off. The spring 12 is permanently under compression and urges the bolt rod into the operative position shown in Figure 2. In this Figure, the bolt rod is engaged in a conventional bolt hole 15, which is adjacent the door jamb 5 as shown in Figure 1, so that the door is bolted shut. The bolt hole 15 is formed at one end of a plate 14 screwed to the floor.

This floor plate also carries a cover plate 13 over the bolt hole, which is pivotable between an open position shown in Figure 1 and a closed position as shown in Figure 3.

Spaced a short distance from the main bolt hole 15, the plate 14 has a recess 21 in which a cam surface 22, sloping downwardly away from the bolt hole 15 towards a vertical end surface 16 which forms a stop.

To open the door from the inside, (i.e. the side on which the bolt is located), the bolt can be drawn in the usual ay, sliding the peg 9 into the circumfe:-ertal part 8 of the bayonet slot to hold it up against gravity and against the bias of the spring 12.

To enable the door to be opened sufficiently to identify a caller without actually allowing entry, the peg 9 is lifted, but kept aligned with vertical slot 10. The cover plate 13 is pivoted into its closed position as shown in Figure 3 and the bolt rod is released so that it bears against the cover plate. If the door is then opened, the bolt rod will run down the cam surface and engage the stop 16, being biassed downwardly by the spring 12. The stop 16 will typically be about 15 cm from the main bolt hole 15, so that the limited opening of the door that this allows will frustrate any attempt to gain entry by force. The door can then be pushed shut, the bolt rod being pushed back up by the cam surface 22. With the door shut, the cover plate can be pivoted to its open position and the bolt shot to secure the door.

If there is a call when the door is bolted, the bolt can still be used to prevent forcible entry, by drawing it and opening the door sufficiently to allow the end of the bolt rod to rest on the plate 14. The bolt then operates as described above to abut the stop 16. If the door is then pushed shut in the face of an unwanted intruder, the bolt rod will slide back up the cam surface 22 and snap back into its bolt hole 15 to prevent further opening of the door.

The bolt assembly is also operable with a key from outside the door. At the top of the bolt rod 10 is a rearward projection 24 which projects through a longitudinal slot 25 in the backing plate 1 into a recess 27 behind the backing plate. Within this recess a tie rod 26 has a hooked lower end 29 engaged through a hole in the projection 24. The upper end of the tie rod is engaged in a hole 29 in a rotatable tongue 28 of a barrel lock 30. the end of this tongue is bent at right angles to its axis of rotation to form a rotating lever.

The lock 30 is operable from outside the door by means of a key 32. When the bolt is in the closed position shown in Figure 2, it can be drawn from the outside by turning the key 32 clockwise. This causes the tongue 28 to rotate anti-clockwise as seen in Figure 1, drawing upawards the tie bar 26 and hence the bolt rod 10 against the bias of the spring 12, lifting the bolt clear of the hole 15.

As the key is turned further the tongue 28 passes the vertical and reaches a stable position as shown in Figure 1, abutting a screw 34 which forms a stop. The door can then be opened fully.

The part of the recess 27 which extends above the bolt is closed off with a plate 35 secured in position by screws 36. The plate 35 is omitted from Figure 1 for clarity.

The bolt can thus be shut from the outside when leaving the building, giving much more security than for example an ordinary barrel lock since it cannot be levered open with a credit card or the like. It also gives added security when used with a mortice lock or the like, since the door is then fastened at two spaced positions and held against twisting.

To secure the bolt from the inside against unauthorised use of a key from the outside,the peg 9 has a threaded shaft 37 received in a correspondingly threaded bore 38 which extends transversely right through the rod. If the peg is screwed in tight its leading end makes a firm frictional engagement with the inner wall of the tube 2 so that even with a key the bolt rod 10 cannot be lifted clear of the hole 15.

It will be appreciated that other key-operated means could be used to draw the bolt, for example a drum and cable or an electrical impulse.

Claims

1. A door bolt assembly comprising a bolt slidable along a tube provided with means for securing it to a door and a spring arranged to urge one end of the bolt rod into an operative position in which it extends from the tube, the rod being settable in two positions, in one of which the bolt is held inoperative against the action of the spring and in the other of which the bolt rod is urged by the spring towards its operative position to engage an aperture, characterised in that key-operated means are provided to enable the bolt to be drawn into its inoperative position against the bias of the spring or released into its operative position using a removable key on the opposite side of the door to that to which the bolt is attached.

2. A door bolt assembly according to claim 1, wherein the key-operated means comprises a barrel-type lock with a rotating tongue projecting from the end of the barrel remote from the key and bent over to form a rotating lever connected to the bolt rod.

3. A door bolt assembly according to claim 2, wherein the connection between the lever and the bolt rod comprises a tie rod extending between the lever and a rearward projection from the bolt rod which extends through a longitudinal slot in the tube.

4. A door bolt assembly according to any preceding claim further comprising means operable from the same side of the door as the bolt to block the key-operated means so that the bolt cannot be operated from the opposite side, with or without the key.

5. A door bolt assembly according to claim 4, wherein the blocking means comprises a threaded peg screwed into a threaded bore extending transversely through the bolt rod, whereby screwing of the peg right through the bore causes the end of the peg to engage the inner wall of the tube and, by friction, hold the rod against axial movement.

6. A door bolt assembly according to any preceding claim wherein the key operated means is movable to a position in which it holds the rod in its axial position even if the key is released or removed.

7. A door bolt assembly according to any preceding claim, in combination with a runner plate securable to a floors or other surface adjacent a door and having a recess or aperture therein to receive the projecting end of the rod in the operative position of the bolt and a smooth surface to enable the end of the rod to run over it.

8. A door bolt assembly according to claim 7, wherein the runner plate comprises a first aperture in the form of a bolt hole to accommodate the bolt rod when the door is shut and a second aperture or recess spaced a distance of 10 to 20 cm from the first to engage the bolt rod in the event of an attempted forced entry.

9. A door bolt assembly according to claim 8, wherein an elongate cam surface extends upwardly from the bottom of the second recess in the direction of the bolt hole, to enable the bolt rod to be moved from the second recess to the bolt hole by pushing the door shut.

10. A door bolt assembly substantially as herein described with reference to the accompanying drawings.