GB2207697A - Security shutter-lock safety and alarm system - Google Patents

Abstract

An unobtrusive electronic switch arrangement, for use with locks on roller-shutter doors and blinds, operates by detecting the presence of the lock bolt when it secures the shutter in its closed position to the fixed guide rail. Sensing of the lock bolt may be by contacting or non-contacting means. The bolt 11 of the lock 16, in the fully entered position, depresses the operating arm 2 of a micro-switch 3. The switch, through a relay or contactor in the shutter drive-motor circuit, prevents energisation of the drive-motor until the lock assembly has been completely withdrawn, so preventing mechanical damage to the system. The arrangement is also intended for use within an associated alarm circuit so that a warning of forced entry or vandalisation can be provided when the lock bolt is illegally moved. <IMAGE>

Description

"Security shutter-lock safety and alarm system Description of invention This invention relates to the incorporation of an electrical switch into mechanical locks designed specifically for securing metal roller-shutters.

Roller shutters are extensively used to prevent illegal entry into warehouses, and to minimise vandal damage to shop and office windows. The shutters, generally vertically moving, may be either motor driven or manually operated depending upon size. The shutters move in vertical metal guides and it is to these that the special vandal-proof locks are attached by welding or rivets.

Shutter locks at present are mainly mechanical in form and action.

In the attached drawings figures 1 & 2 show how, typically, the substantial lock housing is fixed to the shutter guide and accommodates a pin-tumbler or other kind of lock mechanism. Operation of the lock key retracts the lock bolt into the lock body to enable the lock assembly to be withdrawn from the lock housing.

Attached to the lock body is a hardened steel blade which, with the lock in the'secure' position, is located entirely through both of the shutter guide limbs and through the shutter itself (as shows in fig 2).

With the various parts in this position it is impossible to move the shutter, except perhaps through forcing or gross damage. This invention is designed to inhibit the latter events and to make the security system more complete.

According to the present invention the addition of a switch to the lock is intended to extend the use and security of the lock. With appropriate circuitry the switch can be used to prevent inadvertent operation of the shutter drive-motor while the lock is incompletely inserted or removed - a common occurrence - thus avoiding permanent damage to the shutter, guide and lock. Additionally, the switch can be used to operate warning lights (for example on the motor control panel in the above case), or for energising alarms when the system is being tampered with or vandalised. A particular advantage of the invention is that the switch arrangement can be attached to the shutter lock and guide assembly during manufacture, during installat ion of the shutters, or to shutters already installed.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows in perspective a typical arrangement of shutter guide, attached lock housing, and lock assembly - as used today.

Figure 2 shows in detail how a hardened steel end piece attached to the lock assembly passes through the shutter itself and engages with location holes in both limbs of the shutter guide, in the 'secure' position.

Figure 3 shows a particular form of the proposed switch assembly and the orientation of the main components.

Figure 4 shows another vievr of the proposed switch assembly with cover plate, having a self-adhesive coating, in position.

Figure 5 shows a vie of the switch assembly in operation with fRE steel end-piece of the lock initiating first action of the switch mechanism.

Figure 6 shows the orientation of all the essential parts in their 'secure' operational position.

Referring to the drawings, figures 1 & 2 show the basic configuration and principle of operation of a typical shutter lock. This is essentially by means of locking a hardened steel blade into position through the closed shutter, and into adjacent limbs of the shutter guide. The basis of this invention is to provide a lowvoltage switch, or other kind of sensor, which will detect and indicate the presence or absence of the hardened steel blade by electronic means. The shape of the steel blade is suitably adapted to facilitate this. Furthermore, the invention seeks to provide an unobtrusive device which can be easily attached to the rear of the shutter guide, preferably by self adhesive means, even in the confined spaces available behind the shutter guides and between the adjacent masonry.Consideration has also been given to the safe positioning of-electrical leads running to the device , now these can be taken easily to the right or left, according to the needs of the installation, simply by turning around the whole switch assembly.

Figures 3 & 4 show the main features of the invention. In this case a micro-switch (1) is used to detect the presence of the steel blade of the lock. The operating arm (2) of the micro-switch is set in a twisted position to receive the rounded snout of the locks' steel blade Which is extended in length for this purpose (see fig 6). The micro-switch is fixed by rivets (3) or other means to a moulded, pressed, machined, or other processed housing (4). The housing incorporates a recess (5) to accommodate the switch and a slot (6) to correctly locate the steel blade relative to the micro-switch arm. The housing also incorporates a channel (7) to enable electrical leads (8) to be taken to the switch and sealed. The housing is finally closed and sealed by a cover plate (9) attached by mechanical or other means.The external surface of the cover plate will haveeself-adhesive coating (10) to simplify installation as described above.

Figure 5 shows the steel end piece (11) of the lock partially inserted into the switch housing slot (6). This indicates how te specially adapted and extended shape of the steel end piece initially contacts the angled micro-switch blade (2) and slides along it to open/close the switch.

Figure 6 shows the complete assembly of associated parts and includes the switch assembly (12), shutter guide limbs (13), shutter (14), lock housing (15), lock assembly (16), and steel blade (11) of the lock. The lock is showy in the fully entered and 'secure' position with the lock bolt (17) projecting into the lock housing slot (18) thus preventing withdrawal of the lock and opening of the shutter. The steel blade (11) of the lock is shovm completely through the switch housing location slot (6) and terminally positioned b the shoulders (19) acting on the shutter guide limb (13). The narrow parallel part of the steel end piece is shovmfully closing/opening the micro-switch (3) through action on the micro-switch blade (2).

The switch is intended to operate a contactor or relay coil in the shutter drive motor control panel, or to enable/disable part of the logic in an associated circuit. For alarm applications a change-over circuit will be incorporated to adapt to normally closed or normally open circuits.

This example describes an arrangement using a simple mechanical micro-switch. More sophisticated means of switching may be used for particular installations. These means might range from infrared emitters and receivers, with the steel end piece interrupting the beam when inserted, to electro-magnetic, inductive capacitative or other type of sensor.

In like fashion the mechanical parts may be substituted with alternatives. Other kinds of lock for example may be used instead of the pin-tumbler type herein described. Similarly, the steel end piece of the lock may be replaced by other materials.

The example described here involves vertically moving shutters.

The invention can be equally well applied to horizontally moving shutters The above description is by way of example and it is to be understood that all the elements of the described example can be changed, where applicable, for equivalent means for producing the same or similar result.

Security shutter-lock safety and alarm system Drawing Reference Key Page 1/4, Fig 1.

Title: General Arrangement of a Shutter-Lock Feature no 11 - Steel End-piece 13 - Shutter Guide 15 - Lock Housing 16 - Lock Assembly 17 - Lock Bolt 20 - Direction of Shutter motion 21 - Pin-tumbler mechanism 22 - Brass body of Lock Page 1/4, Fig 2.

Title: Sectional Plan View of a locked Shutter Feature no 13 - Shutter Guide 14 - Shutter 15 - Lock Housing 16 - Lock Assembly 23 - Location Holes in Guide and Shutter 24 - Steel..End-piece engaged in Shutter and Guide holes which match End-piece widths in vertical plane Page 2/4, Fig 3.

Title: Rear view of Switch Housing with Cover Plate removed Feature no 1 - Micro-switch 2 - Micro-switch Operating Arm 3 - Micro-switch retsining Rivets 4 - Micro-switch Housing 5 - Housing Recess for Micro-switch 6 - Housing Slot to locate Steel End-piece of Lock 7 - Housing Channel for Electrical Leads 8 - Electrical Leads for Micro-switch Page 2/4, Fig 4.

Title: Sectional end-elevation with Cover Plate in position (section through A-A ref Fig 3) Feature no 1 - Micro-switch 2 - Micro-switch Operating Arm 4 - Micro-switch Housing 5 - Housing recess for Micro-ssitch 9 - Housing Cover Plate 10-Self Adhesive Coating on Cover Plate Page 3/4, Fig 5.

Title: Vertical section (through A-A ref Fig 3) of Switch Assembly with steel End-piece of Lock partially inserted (to first contact with-Micro-switch Blade) Feature no 1 - Micro-switch 2 - Micro-switch Operating Arm 4 - Micro-ssitch Housing 6 - Housing Slot to locate End-piece of Lock 9 - Housing Cover Plate 10-Self Adhesive Coating on Cover Plate 11-Steel End-piece continued Drawing Reference Key - continued Page 4/4, Fig 6.

Title: Vertical section through whole Assembly of Switch, Shutter-guide, Lock Housing and Lock. Latter in fully entered and secure position Feature no 1 - Micro-svitch 2 - Micro-switch Operating Arm 6 - Housing Slot to locate End-piece of Lock 9/40-Housing Cover Plate with Self Adhesive Coating 11-Steel End-piece 12 - Switch Assembly 13-Shutter Guide 14-Shutter 15 - Lock Housing 16-Lock Assembly 17-Lock Bolt 18 - Lock Housing Slot for Lock Bolt 19-Abutment Shoulders on End-piece of Lock

Claims (6)

1. CLAIMS 1 An unobtrusive electrical or electronic switch incorporated into mechanical locking systems, used specifically with roller shutter doors or blinds, to prevent inadvertent operation of the drive mechanism in the case of powered roller-shutters, and to detect and warn of forced illegal entry or vandalisation with both power and manually operated roller-shutters. The switch operates by detecting, through contacting or non-contacting means, the presence or absence of that part of the lock(a blade or bolt) which secures the roller-shutter in the closed position, to its fixed guide rail(s).
2. 2 A switch as claimed in claim 1 wherein the electrical connections are used to link the switch with existing or additional alarm or warning lights to enhance the security of the locking system.
3. 3 A switch as claimed in claim 1 wherein the electrical connections are used, in the case of motorised shutters, within the drive motor circuit to ensure that the shutters can only be operated when the lock bolt is fully withdrawn.
4. 4 A switch as claimed in claim 1 which can be fitted, in a concealed location at the rear of the shutter guide rail, to roller-shutters either being installed or already installed.
5. 5 A switch as claimed in claim 1 which can be fitted to new or existing roller-shutters, with the electrical leads capable of being conveniently taken to the left or right to suit particular installations, simply by rotating the switch and its housing before fixing to the rear of the shutter guide rail.
6. 6 An unobtrusive switch mounted in close proximity to, and operable with, a roller-shutter lock, and substantially as described herein with reference to figures 3 to 6 of the accompanying drawings.