"Improvements in security warning devices" This invention relates to a security warning device, and more particularly to a device which is intended to accompany a security person for use in conjunction with a control post.
A first object of the invention is to provide a hand-operable device to accompany the security person and which is such that it requires to be manipulated in a certain manner so as not to give rise to a breach of security indication.
A second object is to provide in combination with such a device a supervisory equipment which is capable of, at least, responding to the initiation of a breach of security indication by the device, and preferably indicating a direction of the device.
According to the present invention a hand-held security device comprises a truncheon including a handle portion, a transmitter housed in said truncheon, a grippable control means for said transmitter positioned at said handle portion, said control means including resilient loading means which can be overcome by a predetermined gripping force exerted by a user gripping said handle portion in the hand, said control means having a first condition in which it permits emission of a signal by said transmitter and a second condition in which it does not permit emission of a signal by said transmitter,
said control means being urged towards one of those conditions by said resilient loading means, whereby failure by the user to exert said predetermined gripping force results in said control means achieving the other of those conditions to cause emission, or cessation of emission, of a signal.
To cater for the situation that the user might be prevented, by another person, from releasing his grip, the control means preferably has a third condition into which it can be placed by exertion of a predetermined higher gripping force by the user counter to said resilient loading means, to cause emission, or cessation of emission, of the signal.
In a preferred form, the transmitter is a radio transmitter and in particular the transmitter may be constructed to transmit a carrier signal modulated with a coding signal respective to a particular device.
The control means may be, for example, a mechanically operable switch, or an electronically operable switch.
To warn the user of risk of unintentional signalling of a security breach, the security device may comprise alarm means coupled to the control means and arranged, upon occurrence of that other condition
of the control means, to generate a warning signal such as a tone or mild shock, the arrangement being such that if the control means is not returned, by the user, to said one condition within a predetermined short period of time, say a fraction of a second, the transmitter will be made to emit, or cease to emit, its signal.
In accordance with another aspect of the invention, there is provided in combination a security device as set forth above and a supervisory equipment incorporating receiver means, e.g. a radio receiver, to receive a signal transmitted by the transmitter. In a convenient arrangement there are provided a plurality of the security devices, each said device being arranged to transmit a respective different signal, and a supervisory equipment incorporating receiver means having a corresponding plurality of indicators, the receiver means being arranged to actuate a respective indicator when a signal appropriate thereto is received. By way of example, each of the security devices may transmit on a respective different frequency, and the receiver means monitors all of those frequencies. In an alternative construction, each security device transmits on a same frequency a signal having a coding respective to that device, the receiver means including a decoder adapted to identify each device by its coded signal.
In a convenient form a handle for the truncheon ia constructed with a fixed portion and a relatively movable portion the movement of which is arranged to actuate a switch means in the device. By way of example, the device may include a tubular body terminating in a hand grip, the body receiving transmitter means and advantageously an inbuilt power supply, and the hand grip incorporating the switch operating means. The device and the supervisory equipment may be utilised in conjunction with means removably engageable with the device for holding the switch means in the "other" condition. By way of example there may be provided a key which can be inserted in the device and which itself holds the switch means in the other condition, or which operates a latch or lock to hold the switch means in the other condition. Preferably, each such device has an individual different key allotted, and the supervisory equipment may include a respective receiver module which can only be actuated by the insertion and operation of that key removed from the device, thereby giving an immediate indication, to a controller, of which
devices of an entire set are being carried by security persons at any given moment.
In order that the nature of the invention may be readily ascertained, an embodiment of security device and its associated supervisory equipment in accordance therewith are hereinafter particularly described with reference to the figures of the accompanying drawings, wherein:-
Figure 1 is an elevation of a device in the form of a truncheon;
Figure 2 is a longitudinal central section of the device;
Figure 3 is a part perspective view, to a larger scale, of the screw-threaded connection for a "dead man's handle" forming a grip for the truncheon;
Figure 4 is a perspective elevation of a spring and the movable portion of the hand grip;
Figure 5 is a perspective view of a pivot for a trigger; Figure 6 is a perspective elevation of a simple form of supervisory equipment;
Figure 7 shows a circuit for a truncheon transmitter;
Figure 8 shows a circuit for a control point receiver.
Referring to Figures 1 to 5 and 7, the device (hereinafter referred to for convenience as the "guard stick") is intended for use as a warning and defensive device for use by civilian and service patrol men and guards whose tasks may include visits to vital points some distance from a main control point such as a guard room. It may be used to advantage by, for example, individuals who are not armed but are vulnerable to attack by weapons, chemical agents or physical force. Its primary use is a warning device, but it may have secondary uses such as self-defence and as an alertness check device.
Referring to Figures 1 and 5, the guard stick comprises a hollow plastics tube 1 having in it an electronic mechanism 2 (see fig 7) which, when activated, transmits a selective call on a fixed UHF or VHF frequency. The tranmission is received at a control point, and is displayed by audio and visual means on a control panel. The guard stick includes a handle switch 3 having a fixed portion 3a and a movable portion 3b. The movable portion 3b is urged into its rest position by means such as the M-shaped spring 4 seen in Figure 4. Coupled to the fixed and movable portions are switch means controlling operation of the transmitter 2. The switch means are arranged to permit activation of the
transmitter only when the movable portion 3b is in its end position as urged by the spring, i.e. when the user's grasp is released. Activation is thus caused by voluntary or involuntary release of the handle. Closure of the handle stops the transmission, but the control panel would be left operative as long as supervision was required.
The guard stick is advantageously made in three portions, viz, a handle, a main body housing the power source and transmitter, and a screw-on end piece 9. The main body and handle can be coupled by screw-threading 5. When the three parts are joined, the movable contact 6 becomes housed in the hollow end of the transmitter. Inside that hollow end are fixed contacts 6a and 6b.
The movable contact 6 can oscilliate about a pivot 11 secured in the fixed portion of the handle by screws 12.
The movable contact 6 is shown in the position in will assume when the handle portion 3b is normally gripped by the user. Release of the handle portion 3b, or the exertion of a much harder grip thereon, will both cause the trigger 6 to abut against a respective one of the two contacts 6a, 6b. It will be known to those skilled in the art of switch construction that the mechanical switch
illustrated could be replaced by electronic switch means operable by hand capacitance, hand heat, or skin resistance, in combination with micro-switch means positioned beneath a resiliently deformable grip element whose elasticity determines the pressure required to actuate the micro-switch means.
The guard stick includes storage space for a power source 7, containing a rechargeable battery or primary cells. A spiral spring 8 is held in place by the removable screw-threaded cap 9. Advantageously the body of the guard stick is made of a lightweight hardened plastics material. The power source may have a cadmium rechargeable battery, or alternatively torch batteries may be used. The stick includes an antenna e.g. a helix, (not shown), or where a metal stick body is used, part of the body itself may serve as the antenna.
The handle has a hole 10 for a pin or key (see key 23, Figure 6) capable of locking the movable portion 3b in the (grasped) condition.
Referring to Figure 6, there is shown a simple supervisory station having a console 13 with a socket 14 for connection of the apparatus to a cathode ray tube display (not shown) and sockets 15, 16 for connection to direction-finding means (not shown). An audio signal outlet is provided at 17. A power input
cable socket is provided at 18 and an inlet socket for any alternative power source at 19. A coaxial antenna lead socket 20 is for connection to an external antenna (not shown). The console, as illustrated has eight key-receiving openings 21 each with a respective alarm light 22, and a key 23 from each guard stick in use at any one time is inserted in the appropriate opening 21 to set the system at "on". However a lesser or greater number of openings 21 may be used. Each stick holds its respective checking key 23 which has two functions: a. Firstly it acts as a locking pin when the guard stick is not in used and housed in the Control Point. It retains the grip in the closed position. b. Secondly, when the guard stick is being drawn out for use, the locking pin 23 become a recognition key and is inserted into an opening 21 adjacent to the appropriate alarm 22 on the control panel.
The Control Panel, when activated shows a light and produces an audio alarm. Each guard stick working to the Control Panel has a selective call facility which lights up/sounds separate stations on the panel display.
Referring to Fig.7, the transmitter comprises a
crystal-controlled oscillator 24 operating preferably at its first harmonic, and multiplied by a frequency multiplier 25 to a working frequency, for high stability. The carrier frequency may be optionally modulated by a simple code signal, from an encoder 26, suitable for identifying the truncheon in use form others. The modulated or un-modulated signal passes through a buffer stage 27 to a pre-amplifier 28, power amplifier 29 and transmitting antenna 30. A switch means 31, which may be a simple mechanical switch such as 6 , 6a 6b ( f ig . 1 ) or an electronic sensing means 32 in combination with microswitch means 33, is connected through an alarm condition detector 34 to an alarm warning means, e.g. audible transducer or shock-giving device 35.
When an alarm condition, of the truncheon switch means 31, is detected by the detector 34, an alarm warning is sent to the guard by warning device 35, and a feedback loop tests within the detector 34 if the alarm condition has been removed, after a very short time interval derived from the oscillator 24 and a counter circuit in the detector. If the alarm condition still exists after that short period, an on/off control 36 is actuated to allow/disallow transmission, according to the mode of operation desired.
Referring to fig.8, the control point installation comprises an antenna 37 coupled to a filter 38 feeding a receiving amplifier 39 for driving a receiver monitor 40. Where an identifying modulation is used by the transmitter, decoder means 41 may be incorporated. The receiver scans the respective frequencies allocated to the various truncheons in use, or where the carrier frequency of all of the truncheons is the same, it decodes the identifying code signal.