GB2178474A

GB2178474A - Security devices

Info

Publication number: GB2178474A
Application number: GB08614871A
Authority: GB
Inventors: Michael John Furness; Michael John Sykes
Original assignee: SEAFARER NAVIGATION INTERNATIO
Current assignee: SEAFARER NAVIGATION INTERNATIO
Priority date: 1985-06-18
Filing date: 1986-06-18
Publication date: 1987-02-11
Also published as: GB8515355D0; GB8614871D0; GB2178474B

Abstract

A control device for a door comprises a door lock assembly which permits the door normally to be maintained closed but which enables the door to be opened by the application of a pressure force in excess of a predetermined level, for example in a panic situation. The door lock assembly comprises a clutch mechanism consisting of a rotatable shaft (40) connected to a door latch (34) and a coil spring (54) which encircles the shaft. By tightening and loosening the coil spring relative to the shaft, the shaft can be locked against rotation or freed for rotation. Tightening and loosening of the coil spring (54) is effected by electrically energised means, here a solenoid, operating through a compression spring (72) and a push rod (58) which pushes against the free end (56) of the coil spring (54). When the solenoid is de- energised the lock opens. <IMAGE>

Description

SPECIFICATION Security devices This invention relates to the opening and closing of doors, gates, turnstiles, windows, etc.

The term "door" as used hereinafter is to be understood as including within its scope any movable member which can provide a barrier to the entrance or exit of people past or through that barrier. One particular application of the present invention is to the control of gates, doors and turnstiles in stadia, such as football stadia, where large crowds are present. In such circumstances it is desirable to be able to maintain barriers closed under normal circumstances, but to be able to release such barriers for mass exit should the need arise.

It is an object of the present invention to provide a control device for doors as herein defined by means of which a door or a plurality of doors can be opened rapidly from a remote location.

It is a further object of the present invention to provide a control device for doors as herein defined such that a door or doors can be maintained closed but can be opened by the application of a pressure force in excess of a predetermined level.

In accordance with one aspect of the invention there is provided a control device for controlling the opening and closing of a door or doors as herein defined, wherein the control device comprises electrically energised means to provide sufficient resistance to the opening of a door latching mechanism normally to maintain the door closed, with said means being arranged to respond to removal of the energising force by removing said resistance and permitting the door to open.

The electrically energised means which provides sufficient resistance to the opening of the door latching mechanism may be electromechanical, electro-magnetic, electro-optical or even electro-acoustic. In one preferred embodiment of the invention the electrically energised means comprises a clutch, particularly a friction clutch.

Preferably, the control device, as well as causing the door to open when the electrical power supply is interrupted, is also such that sufficient pressure against the door will cause the door to open even when the elctrical power supply is maintained. This is an additional safety feature whereby the electrically controlled device can be overridden by sheer mechanical pressure, as in the event of a crush of bodies against the door in a panic situation.

In accordance with another aspect of the present invention there is provided a door lock assembly comprising a door latch which is cooperable with door stop means, rotatable shaft means connected to said door latch and mounted within a door lock housing, coil spring means positioned around said shaft and arranged to be tightened and loosened thereby frictionally to engage with and disengage from said shaft, and electrically energised means to control the tightening and loosening of said coil spring means, said electrically energised means being arranged to respond to application or removal of the energising force by the freeing of said coil spring means from the shaft and permitting the door to open.

Two embodiments of control device in accordance with the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a schematic illustration of a first embodiment of control device, using a friction clutch to control the opening of a door; Fig. 2 shows part of the device of Fig. 1; Fig. 3 is a side view of a second embodiment of control device, with the outer housing removed; and, Fig. 4 is a sectional view taken along the line IV-IV of Fig. 3.

Referring first to Figs. 1 and 2, the edge of a pivotally opening door or gate or like member is indicated at 10. Attached to the door or gate or like member adjacent to that edge is part of a door latching mechanism which here is shown as a solid bar or bolt 12 which projects from a solid block attached to the door itself. Mounted on, or housed within the contours of, the door frame or equivalent structure relative to which the door is movable is a friction clutch indicated generally at 14 by a broken line. This friction clutch 14 is a conventional device comprising a fixed component 16 and a movable component 18 which takes the form of a friction plate which is movable towards and away from the fixed component 16 in order that it can move between a frictionally locked position and a freely rotatable position.The movable friction plate 18 is mounted on a shaft 20 which is rotatable with the plate 18. Attached to the end of the shaft 20, or integral with it, is a generally U-shaped latch 22. The door bolt 12 is dimensioned to fit within the recess defined by the arms of the latch 22, as shown most clearly in Fig. 2.

The friction clutch 14 is energised from an electrical power supply indicated by the terminals 24. This is preferably a dc power supply of up to approximately 50 volts. Two signal lamps 26 are also connected to the friction clutch assembly and to the circuitry thereof in order to indicate whether the door latching mechanism is "on" or "off".

In use, with the electrical power supply 24 switched on, the friction clutch is energised and the movable plate 18 is held fast against rotation. With the U-shaped latch member 22 in an upright position and with the bolt 12 captive within it, the door is thus prevented from opening. However, as soon as the power supply to the friction clutch 14 is re moved, the plate 18 and shaft 20 are freely rotatable and the resistance to the door 10 being opened is thereby removed. Pushing the door 10 causes the bolt 12 simply to pivot the latch member 22 through 90" and thereby release the captive bolt.

Because of the nature of friction clutches, there will be a certain force which, if applied to the shaft 20 by way of the latch member 22, will cause the shaft 20 and movable plate 18 to rotate even when the electrical power supply is still on. In other words, by exerting sufficient pressure against the door 10 in the direction to open it, one can override the friction clutch and open the door. This is a further safety feature. The force needed to open the door in the event that the power supply is still maintained can be set according to parti cular needs by appropriate choice of the friction clutch mechanism. Clearly, it should not be possible easily to override the friction clutch when the power supply is on, but it may be necessary from a safety viewpoint that there is a limit above which the clutch mechanism is overridden.Alternatively, if one does not wish to have an override facility, then some alternative electrically energised mechanism may be used which will only release the latch member for movement when the power supply is interrupted.

The means whereby the power supply is switched off in order to release the door 10 may take any one of a number of forms, and indeed the system may be arranged so that.

the energising power supply can be switched off by any one of a combination of different means. For example, one could have a remote control panel linked to the door or doors in order to provide a centralised control facility.

This could be linked into means for releasing individual doors locally, i.e. at the door itself, for example by using a key-operated mechanism or a "smash-the-glass" mechanism for example.

The door mechanism could also be controlled by radio signals which would operate appropriate relays or equivalent devices within the control mechanism itself. This again would help to achieve swiftness of response in the event of an emergency.

As an alternative to using a friction clutch, one could for example use a solenoid with appropriate gearing to generate the necessary resistance to opening. It would also be feasible to add gearing to the friction clutch mechanism in order to provide for an increased resistance to opening or to enable a lower torque clutch to be used. Yet again, electrically energised latching means could be used which are responsive to optical or acoustic signals for their release. Also within the scope of the present mechanism are door mechanisms of the general type referred to above which incorporate smoke detecting means which react, on detecting smoke, by switching off the energising power supply and thereby opening the door.

A second, and preferred, embodiment of control device in accordance with the invention is shown in Figs. 3 and 4. Here, the door stop is shown at 30 and has a projecting bolt 32 which engages with a door latch 34. The control mechanism is arranged within a lock housing 36 which, in its face adjacent to the door latch 34, is provided with a bore fitted with a bearing 38 for a shaft 40. The door latch 34 is held in place on the shaft 40 by a bolt 42 and washer 44. A roll pin 46 projects from the housing 36 outwardly into a bore formed in the door latch 34. The end portion of the shaft 40 remote from the door latch 34 is supported by a bearing 48 and is provided at its end with a torsion spring 50 co-acting with a roll pin 52 mounted in the lock housing 36. A coil spring 54 is wrapped around the shaft 40 which is connected to the door latch 34. The coil spring 54 has its one end, i.e.

the right-hand end as shown in Fig. 3, held fixedly. The other end of the coil spring 54, indicated in Figs. 3 and 4 at 56, is engageable by a spring pusher 58. The spring pusher 58 is mounted upon a plate 60 secured by a bolt 62 and lock washer 64 to the upper end of a solenoid plunger 66. The solenoid bobbin is indicated at 68 and the energising coils at 70. A compression spring 72 extends between the underside of the plate 60 and the bobbin 68 and is positioned coaxially around the solenoid plunger 66.

The operation .of the door lock mechanism shown in Figs. 3 and 4 is as follows. Because the coil spring 54 is held firmly at one end, when the spring shaft 40 turns in the direction for the door to open, the coil spring 54 is tightened up on to the shaft, i.e. its internal diameter reduces, thereby frictionally engaging the shaft 40 and stopping the shaft from rotating. Thus, in the normal position, the interaction of the coil spring 54 and shaft 40 will prevent the door from being opened. The lock is released by forcing open the coil spring 54 by pushing the coil open at the non-attached end of the spring, i.e. at its end 56, thereby enlarging the internal diameter of the coil and allowing the shaft 40 to rotate within the coil spring.

This opening movement of the coil spring 54 to free the locking mechanism is effected in this embodiment by the use of the compression spring 72 which operates upon the plunger of an inactivated solenoid. When the solenoid is active, this compression spring 72 is compressed by the solenoid plunger 66 which, in moving into the solenoid, allows the main coil spring 54 to close around the shaft 40 of the lock, thereby stopping the lock latch 34 from turning. Thus, in this embodiment, the lock will open when the solenoid is deenergised. It will be apparent to persons skilled in this art that it is possible to modify the assembly so that the lock operates in the opposite mode, i.e. so that the lock opens when the solenoid is energised.

In an alternative embodiment of control device in accordance with the invention, the door lock assembly may be provided with a facility for key operation which will override the solenoid or which can be used on a longterm basis, for example on cinema doors where the system would only be required to be powered-up while people were using the building. During other times, with the power off, the locks would be secured mechanically by the use of a key.

Claims

1. A control device for controlling the opening and closing of a door or doors as herein defined, wherein the control device comprises electrically energised means to provide sufficient resistance to the opening of a door latching mechanism normally to maintain the door closed, with said means being arranged to respond to removal of the energising force by removing said resistance and permitting the door to open.

2. A control device as claimed in claim 1, in which the electrically energised means comprises a clutch.

3. A control device as claimed in claim 2, in which the clutch is a friction clutch.

4. A control device as claimed in any preceding claim, in which the electrically energised means which provides sufficient resistance to the opening of the door latching mechanism is electro-mechanical, electromagnetic, electrn-optical or electro-acoustic.

5. A control device as claimed in any preceding claim, in which the exertion of a predetermined pressure against the door will cause the door to open even when the electrical power supply is maintained.

6. A control device as claimed in any preceding claim, in which the electrically energised means comprises spring means encircling the shaft which is connected to a latch of the door latching mechanism, the closing and opening of the door latching mechanism being effected by the tightening and loosening respectively of said spring means against the shaft.

7. A control device as claimed in claim 6, in which the movement of the spring means in relation to the shaft is effected by further spring means functioning under the control of a solenoid mechanism.

8. A control device as claimed in claim 6 or 7, in which one end of said spring means encircling the shaft is held fixedly and the other end of said spring means around the shaft is engageable by a pusher whose movement is controlled by a linearly movable push rod mechanism.

9. A control device as claimed in any preceding claim, which includes a key-operated mechanism to override the electrically energised means.

10. A door lock assembly comprising a door latch which is co-operable with door stop means, rotatable shaft means connected to said door latch and mounted within a door lock housing, coil spring means positioned around said shaft and arranged to be tightened and loosened thereby frictionally to engage with and disengage from said shaft, and electrically energised means to control the tightening and loosening of said coil spring means, said electrically energised means being arranged to respond to application or removal of the energising force by the freeing of said coil spring means from the shaft and permitting the door to open.

11. A door lock assembly as claimed in claim 10, in which the exertion of a predetermined pressure against the door will cause the door to open even when the coil spring means is in tight engagement with said shaft.

12. A control device for controlling the opening and closing of a door or doors, substantially as hereinbefore described with reference to Figs. 1 and 2 or Figs. 3 and 4 of the accompanying drawings.