GB2144170A - Security door - Google Patents

Abstract

A security door comprising a plurality of locking tongues (8,9) which are extendible from the door into the door jamb and a conventional resiliently biased latch plunger (5). The latch plunger is able to operate independently of the locking tongues when the tongues are retracted. However, when the tongues are extended an interlocking means (29) comprising a kink 29 in an actuating rod 17 dead-locks the latch plunger in its extended position by abutting the rear face 30 of the plunger. <IMAGE>

Description

SPECIFICATION Security door The present invention relates to security doors and, in particular, provides a door having a plurality of locking tongues which are extendable from the door into the door jamb.

Previously known security doors have employed complex lever mechanisms to operate two or more locking tongues. The cost and complexity of these mechanisms have made them unsuitable for domestic use, particularly where the security function is not always required.

It is an object of the present invention to provide a security door which is suitable for domestic use and wherein the additional security function can be selectively engaged independently of the normal door latching function. The invention allows the normal door latch to operate independently of the security system, but when that system is actuated, it also locks the normal latch which then forms part of the security locking function. Preferably, the system employs a centrally mounted conventional sliding tongue latch and two transversely extendable locking tongues respectively located at the upper and lower ends of the lock stile, thereby providing a triple locking security system.

According to the invention there is provided a security door of the type including a resiliently biased latch plunger, a plunger retraction actuator operatively connected with said plunger, at least one locking tongue, selectively operable locking means operatively connected with said tongue, characterised in that said locking means includes interlocking means, which, upon actuation of said locking means, locks said plunger against retraction.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which, Figure 1 is a front elevation of a security door according to the invention.

Figure 2 is a side elevation of the door taken in direction 2-2 of Figure 1.

Figure 3 is an enlarged fragmentary sectional front elevation of the door locking mechanism.

Figure 4 is a section taken on line 4-4 of Figure 3.

Figure 5 is a section taken on line 5-5 of Figure 3.

Figure 6 is a section taken on line 6-6 of Figure 3.

Figure 7 is a section taken on line 7-7 of Figure 3.

Figure 8 is a section taken on line 8-8 of Figure 3.

Referring to the drawings, the security door includes a hinge stile 1 and a lock stile 2. Hinges 3 secure the door to the door jamb (not shown). The door panel 4 is formed from a strong metal sheet, grill or other material as required.

The lock stile 2 includes a conventional spring latch plunger 5 actuated by a pair of handles 6. In accordance with the invention, however, the door also includes a security lock 7 which actuates a pair of auxiliary locking tongues 8 and 9 which extend from the door into appropriate keeper slots located in the door jamb (not shown). The locking tongues are illustrated in their operative or locking position.

As best shown in Figures 3 and 4, each locking tongue is arcuate in form and mounted for rotation about an axis 10 under the action of respective drag links 11 and 12 pivotally connected to each tongue by pin 13. The arcuate form of the locking tongues permits them to move in and out through minimum size slots 14 formed in the side wall 15 of the lock style 3.

The drag links 11 and 12 are each connected to slide bars 16 and 17 respectively which are operated by the security lock assembly 7. The lock 7 includes a conventional lock barrel 18 which is operable by a key from the front or rear of the door or by a locking handle 19 located on the inner side of the door. A "deadlock feature may be included whereby the internal locking handle can be rendered inoperative if required.

Operation of the lock barrel and associated handle is conventional and need not be described further.

Rotation of the lock causes a pair of operating levers 20 to rotate and thereby simultaneously extend or retract the slide bars through pins 21 which engage with respective slots 22 on each slide bar.

The slide bars move along a fixed guide plate 23.

It will be appreciated that turning the key in the lock barrel or operating the inner lock handle to rotate the lock 7 will cause both locking tongues to extend or retract simultaneously as required.

In normal operation, both locking tongues are retracted and the door is operated normally by the conventional latch handles 6. Rotation of either handle 6 in either direction from the horizontal position shown rotates the lock axle 24 and operating arms 25. This rotation brings one or other operating arm into contact with one of a pair of anvil members 26 forming part a slidably mounted latch plunger 27, thereby to draw the plunger back against the action of return spring 28. When the handle is released, the plunger can return to its fully extended or locking position. When the door is pushed closed, the plunger 27 will automatically ride over the latch tongue (not shown) on the door jamb and spring into engagement with its keeper slot. It will be appreciated that the operation of this latch is quite conventional.

In accordance with the present invention, however, the security locking system provides means whereby actuation of the security lock also locks the latch plunger 27. In the illustrated preferred embodiment, this locking function is effected by providing the slide bar 17 with a raised portion 29 which blocks the rear end 30 of the latch plunger 27 and prevents retraction of the plunger when the locking tongues have been extended, as shown in Figures 3, 7 and 8. The locking system thereby holds the plunger in its locked position within the door jamb such that the plunger forms a triple locking security system together with the two aux iliary locking tongues.

When the security system is unlocked, the raised portion 29 moves out of register with the plunger 27 so that the central latch can operate normally.

It will be appreciated that the invention provides a simple form of security system which leaves the normal door latch free for conventional use when the full security system is not required but which operates in combination with this latch to provide an improved security locking system when activated.

Although the invention has been described with reference to a specific example, it will be appreciated that the invention may be embodied in many other forms.

Claims (7)

1. A security door of the type including a resiliently biased latch plunger, a plunger retraction actuator operatively connected with said plunger, at least one locking tongue, selectively operable locking means operatively connected with said tongue, characterised in that said locking means includes interlocking means, which, upon actuation of said locking means, locks said plunger against retraction.

2. A security door according to claim 1 wherein said interlocking means comprises a movable bar including a blocking element for obstructing said plunger, thereby locking it against retraction.

3. A security door according to claim 2 wherein said blocking element comprises a raised portion formed in said movable bar.

4. A security door according to any one of the preceding claims wherein said locking tongue is arcuate in form, concentric with a central axis of rotation.

5. A security door according to any one of the preceding claims wherein said security door includes a hinge stile and a lock stile, two said tongues, said plunger and said locking means being located on said lock stile, said plunger being located intermediate said tongues.

6. A security door according to claim 5 wherein said locking means comprises a rotatable lock barrel and a pair of oppositely directed slide bars, each connected to a respective drag link, each said drag link being pivotally connected to one of said tongues, one of said slide bars comprising said interlocking means.

7. A security door substantially as herein described with reference to the accompanying drawings.