GB2137686A - Security bolt - Google Patents

Abstract

The security bolt device, which enables a door to be held in a slightly open position, comprises a bolt rod 10 slidable along a tube 2 secured to a backing plate 1 that is securable to a door 3. A compression spring 12 is interposed between one end of the bolt rod 10 and a location 11 inside the tube, the other end of the rod being engageable in an aperture 16 in a member 14 set in the floor and spaced rearwardly of the door 3 to any desired extent. The rod 10 is settable in two positions in one of which a peg 9 is located in portion 8 of a slot 6 and the bolt is inoperative and in the other of which the peg 9 lies in portion 10 of the slot 6 and the bolt rod 10 can engage in the aperture 16 in the said member 14 when the door has been partly opened. A centrally pivoted lever (Figs. 2-4) may be mounted on the backing plate 1 to displace the peg 9 from portion 8 of slot 6 when the lower end of the lever encounters an abutment surface on a member 17 mounted adjacent aperture 16. <IMAGE>

Description

SPECIFICATION Security bolt The present invention relates to bolts for premises, particularly, though not necessarily, for domestic dwellings.

Conventionally for security of premises there is used a chain fastener in which a security stub secured to a chain is engaged in a slide fastened to a door. This is a reasonably effective deterrent, but does not prevent a determined intruder bursting open the door by using body pressure.

It is an object of the invention to provide a security bolt that can readily be set by anybody, including the relatively infirm, that will be effective against intruders and considerably more resistant than the chain fastener, and nevertheless be inexpensive to produce.

The invention accordingly consists in a bolt assembly for securing to a door, which comprises a bolt rod slidable along a tube carried by a backing plate that is securable to a door, a spring being provided to urge one end of the bolt rod to 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 which the bolt can be urged by the spring to its operative position in which it can engage in an aperture when the door has been opened a predetermined amount to enable the door to be held secured in a partly open position.

If desired, the spring-loaded bolt rod may be arranged to be released by a trigger mechanism that cooperates with a stop fixed adjacent said aperture.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which shows two embodiments of the security bolt, by way of example, and in which: Figure 1 shows a perspective view of a first embodiment attached to a door, the door being shown slightly open, Figure 2 shows a perspective view of a second embodiment incorporating a trigger mechanism for releasing the bolt rod, the door being shown closed, Figure 3 shows a side view of the embodiment of Fig. 2, the trigger being shown just about to contact a stop member, Figure 4 shows a side view of the embodiment of Fig. 2 but where the trigger has contacted the stop member and released the bolt, and Figure 5 shows a detail on a larger scale.

Referring now to the drawings, Fig. 1 shows a bolt comprising a backing plate 1 and a tube 2, the two parts being extruded in one piece for example of brass. The backing plate 1 is secured to a door 3, only part of which is shown, by screws 4, and may protrude beyond the bottom of the door, as shown, thus avoiding any step that may be present. The door is shown slightly open, i.e.

separated from the frame, part of which is shown at 5.

The tube 2 is provided with a bayonet slot 6 comprising a longitudinal portion 7 and a transverse portion 8 to receive a peg 9.secured to a bolt rod 10 slidable and rotatable in the tube 2.

Between the upper end of the rod 10 and a location 11 in the tube, typified as a brazed plate 11, is a compression spring 12. In the inoperative position of the bolt, the peg 9 engages in the transverse portion 8 of the bayonet slot, maintaining the spring 1 2 under compression.

To set the bolt so that it can provide security on opening the door to a caller, the peg 9 is pushed sideways, as shown in the drawing, rotating rod 10 in the tube 2, to meet the longitudinal portion 7 of the bayonet slot whereupon the spring 1 2 urges the rod 10 downwards where it strikes a cover 1 3 pivoted to a runner plate 1 4 secured to or in the floor and covering a normal bolt hole 1 5.

As the door is opened, after a predetermined travel the rod 10 contacts an aperture 1 6 formed both in the plate 14 and in the floor and engaged positively therein, under pressure from the spring 12, thereby immobilising the door. To assist this action, a stop plate 1 7 may be provided, having a cut-out 1 8 against which the bolt rod 10 engages. The stop plate 1 7 may be separate and engageable in the plate 1 4 by pegs 1 9 therein passing into apertures 20 in the plate 14. This enables the stop plate 1 7 to be removed so that it does not normally protrude above floor level, being put in place only when the door is to be opened under security provision.

Normal body pressure against the door when the bolt rod 10 is engaged in the aperture 1 6 will not force the bolt and assuming sufficiently stout manufacture the door will have to be broken down to gain access.

The protrusion of the tube 2 to the lowest possible extend affords maximum support for the rod 10.

To secure the door in the closed position, e.g. at night, the plate 1 3 is pivoted to uncover the bolt hole 1 5 and the peg 9 is moved to release the bolt rod 10 to enable the latter to pass into the bolt hole.

In the daytime, the householder would normally unbolt the door, against pressure of the spring 1 2 rotating the bolt rod 10 is doing so, so that the peg 9 engages in the transverse portion 8 of the bayonet slot 6. The plate 13 is then pivoted to cover the bolt hole 1 5 i.e.

the position shown in the drawing, ready to set the bolt to the security position when required.

The cover 1 3 may be arranged to slide instead of pivot.

A second embodiment of a security bolt according to the invention is shown in Figs.

2-5 wherein parts corresponding to the embodiment of Fig. 1 bear the same reference numerals. In this embodiment there is additionally provided a trigger mechanism for automatically and positively releasing the bolt rod 10. In Fig. 2, the spring 12 is not shown.

To one side of the tube 2 is provided a Ushaped bracket 21 having a pin 22 whose shank passes through slots 23. The shank of the pin 22 carries a U-shaped mounting 24 for a cranked trigger 25 which is pivotally mounted on a further pin 26 passing through the trigger 25 and mounting 24. The trigger 25 is spring-urged by a hairpin spring 27 passing round the shank of pin 22 into the position shown in Figs. 2 and 3 in which its upper portion 28 rests against the plate 1.

Fig. 5 shows the details of the bracket mounting 21,24 and hairpin opening 27 more clearly. In the operative position shown in Figs. 2 and 3, the peg 9, engaged in the transverse portion 8 of the bayonet slot and compressing spring 12, can contact the upper portion 28 of the trigger arm.

In this embodiment, the bolt is set automatically, and as the door is opened, the lower part 29 of the trigger arm eventually contacts a stop member 30 which is removably secured to a floor plate 31 by pegs 32 so that it may be removed when not required.

Further movement of the door presses the lower part 29 of the trigger rearwardly against the action of spring 27 which in turn causes the portion 28 to push peg 9 out of the bayonet slot portion 8 and causes the bolt rod 10 to be urged into an aperture 33 in plate 31 under the action of spring 1 2 and secure the door in a slightly opened position. The action is therefore similar to that of the arrangement of Fig. 1, except that it is automatic. It will be apparent that no runner plate like the runner plate 14 of Fig. 1 is necessary and there is no need to cover over the normal bolt hole which is not shown in Figs. 2,3 and 4.

The slot 23 enables the vertical position of trigger 25 to be adjusted relative to the stop member 30.

Claims (14)

1. A bolt assembly for securing to a door, which comprises a bolt rod slidable along a tube carried by a backing plate that is securable to a door, a spring being provided to urge one end of the bolt rod to 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 can be urged by the spring to its operative position in which it can engage in an aperture when the door has been opened a predetermined amount to enable the door to be held secured in a partly open position.

2. A security bolt as claimed in claim 1, in which the tube is provided with a bayonet slot comprising a longitudinal portion and a transverse portion to receive a peg secured to the bolt rod which is both slidable and rotatable in said tube.

3. A security bolt as claimed in claim 1 or 2, in which a compression spring is provided between said one end of the bolt rod and a location in the.tube and in which, in the inoperative position of the bolt rod, the peg engages in the transverse portion of the bayonet slot thereby maintaining said spring under compression.

4. A security bolt as claimed in claim 3, in which in order to operate the bolt rod the peg is pushed sideways to rotate the bolt rod in the tube until the peg meets the longitudinal portion of the bayonet slot whereupon the spring urges the bolt rod downwards to its aperture engaging position.

5. A security bolt as claimed in any preceding claim in combination with a runner plate over which the bolt rod travels as the door is opened until is engages in said aperture under pressure from the spring, thus immobilising the door.

6. A security bolt as claimed in claim 5, in which a stop plate is provided having a cut out against which the bolt rod engages, said stop plate being mounted on said runner plate adjacent said aperture.

7. A security bolt as claimed in claim 6, in which the stop plate is detachably secured to the runner plate and is separable therefrom.

8. A security bolt as claimed in any one of the preceding claims, in which the springloaded bolt rod is arranged to be released by a trigger mechanism which is actuated by a stop member fixed adjacent said aperture.

9. A security bolt as claimed in claim 8, as dependent on any of claims 2 to 7, in which the trigger mechanism comprises an arm which has one end located adjacent the peg and which is pivotable against the action of a spring member such that when its other end engages said stop member as the door is opened, said arm pivots against the action of its associated spring member so that its one end pushes the peg out of the bayonet slot portion in which it normally rests and causes the bolt rod to be urged into said aperture under the action of its spring and thereby secure the door in a partly opened position.

10. A security bolt as claimed in claim 9, in which the trigger arm is pivotally mounted in a mounting to one side of the tube housing the bolt rod.

11. A security bolt as claimed in claim 10, in which the mounting is carried by a pin passing through a slot in a bracket secured to the back plate adjacent the tube.

12. A security bolt as claimed in claim 11, in which the trigger arm is a cranked arm and is spring-urged by a spring located about the pin.

1 3. A security bolt substantially as hereinbefore described, with reference to Fig. 1 of the accompanying drawings.

14. A security bolt substantially as hereinbefore described, with reference to Figs.

2,3,4 and 5 of the accompanying drawings.