GB2201820A

GB2201820A - Vehicle theft alarm

Info

Publication number: GB2201820A
Application number: GB8705002A
Authority: GB
Inventors: Ronald James Reid
Original assignee: KAC Alarm Co Ltd
Current assignee: KAC Alarm Co Ltd
Priority date: 1987-03-04
Filing date: 1987-03-04
Publication date: 1988-09-07
Also published as: GB8705002D0

Abstract

An alarm is actuated by the application of a load to a seat 1 of the vehicle. Load on the seat is sensed by a switch to which comprises an insulating tube (Figs 2 and 3, not shown) having a fixed contact (10) at one end and a movable contact (11) mounted on a piston (13) and urged by a spring (16) into contact with the fixed contact. The switch is suspended beneath the seat by resilient, elongate elements 7, 17, one connected to the tube and the other to the piston rod (14). The switch may, alternatively, be arranged within the seat or may be attached to or incorporated into the backrest 2 of the seat. <IMAGE>

Description

Title: Car Alarm Description of Invention This invention relates to an alarm which may be fitted to a motor vehicle to reveal the presence of an intruder in the motor vehicle.

Presently there are available to the public a number of devices which may be fitted to a motor vehicle to prevent or discourage theft of the vehicle or of items from within the vehicle. The two main types are alarms which respond to the opening of a door of the vehicle and alarms which respond to rocking or vibrating of the vehicle.

According to a first aspect of the invention we provide an alarm which reveals the presence of an intruder in a motor vehicle which alarm is activated in response to a load placed upon a seat of the vehicle.

The alarm may comprise a sensing means which detects movement of part of the seat and is responsive to a load placed upon the seat.

The load may bring about reversible deformation of a part of said sensing means.

The alarm may also comprise signalling means to alert a person in the vicinity of the vehicle to the intruder when the sensing means detects said movement.

The signalling means may comprise-an audible signalling means such as a siren, bell, or buzzer and/or a visual signalling means such as a flashing light.

The alarm may be set in an activated condition such that the signalling means may be activated by electrical signals from a power source.

If desired an indicator may be provided, for example on the dashboard of the vehicle, to indicåte to the driver that the alarm has been activated.

The sensing means may be located within a part of the seat which part,in use, normally supports the bottom and legs of a user of the seat.

In an alternative embodiment of the invention the sensing means may be disposed beneath a part of the seat which part, in use, normally supports the bottom and legs of a user of the seat.

When the sensing means is disposed beneath the seat it is at least partially in contact with a part of the base of said part of the seat.

In a preferred embodiment of the invention the sensing means comprises a hollow tube provided internally with a fixed metal contact and a movable metal contact which is attached to a piston which piston is movable longitudinally within the tube, said contacts being urged into mutual contact by spring means acting between the piston and an end of the tube, and supporting means suspending said tube between upwardly extending sides of the seat.

In the preferred embodiment of the invention the contacts, when mutually touching, complete an electrical circuit which prevents actuation of the signalling means when the alarm is activated.

In the preferred embodiment of the invention the supporting means comprises a first resilient member connecting a first end of the tube and an first side of the seat and a second resilient member connecting a rod of the piston, which rod protrudes from a second end of the tube and second side of the seat.

The resilient members tend to pull the piston away from the fixed contact but in the absence of a load on the seat they do not do so because of the action of the spring means which is within the tube.

In the preferred embodiment of the invention, when a load is placed upon the seat the seat deforms and the resilient members also deform and, if the load exceeds a certain value the force exerted by the resilient members overcomes the force exerted by the spring means such that the end of the tube and the end of the piston rod are pulled in opposite directions and the contacts are moved apart.

When the contacts are moved apart the electrical circuit is broken and the signalling means is actuated by electrical signals from the power source.

It will be appreciated that if the electrical wiring which is connected to the contacts is cut by an intruder attempting to deactivate the alarm the electrical circuit is broken and the signalling means is actuated.

The resilient members and spring means may be selected so as to produce divergence of the contacts in response to any desired load. In this way the sensitivity of the alarm may be chosen to suit the particular requirements of a user. For example the alarm may be of insufficient sensitivity to respond to a coat or brief case left upon a seat but of sufficient sensitivity to respond to the load produced by a person of light weight.

Preferably when the sensing means is disposed beneath the part of the seat which part, in use, normally supports the bottom and legs of a user of the seat, the resilient members are covered with a guard to prevent severing thereof and deactivation of the alarm.

According to a second aspect of the invention there is provided a method of detecting and announcing the presence of an intruder in a motor vehicle by sensing the weight of the intruder upon a seat of the vehicle by sensing means, and translating a response of the sensing means into actuation of signalling means which may alert a person in the vicinity of the vehicle to the intruder.

The preferred method involves using an alarm having characteristics in accordance with the first aspect of the invention.

Whilst the alarm does not respond to an intruder until the intruder has actually gained access to the interior of the vehicle it has certain advantages over the alarms which are presently available. For example, alarms which respond to the opening of the doors of a vehicle do not respond to the breaking of windows of the vehicle through which a thief may gain access.

Furthermore, alarms which are based upon sensing vibration or rocking of the vehicle are prone to activation at inappropriate times and under inappropriate conditions whilst sometimes failing to respond to an intruder.

Because it is very difficult for an intruder to steal a car or an item contained in a car without sitting, kneeling or leaning upon a seat of the car the present invention will provide an efficient alarm to deter, frighten, or lead to the arrest of thieves.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings wherein: FIGURE I shows a front elevation of a car seat with the sensing means of the alarm disposed beneath a part of the seat which part, in use, supports the bottom and legs of a user of the seat.

FIGURE 2 shows part of the sensing means in the condition which pertains when there is no significant load upon the seat.

FIGURE 3 shows the sensing means of Figure 2 in the condition which pertains when a sigificiant load is placed upon the seat.

In Figure 1, 1 is a car seat comprising a backrest 2 and a part 3 which, in use, normally supports the bottom and legs of a user of the seat and 4 is an upwardly extending side of the seat which connects the seat to a floor of the vehicle 5.

Suspended beneath the base of part 3 is a hollow tube 4 which is connected to the sides 4 of the seat by resilient member 7 and 17.

In a specific embodiment of the invention the resilient members 7 and 17 comprise flexible, extensible wires.

In on alternative embodiment elastically deformable webbing may be used for the resilient members.

The hollow tube 6 forms part of an electrical circuit of which 8 and 9 are connecting wires.

The hollow tube 6, resilient means 7 and 17 and connecting wires 8 and 9 together comprise the sensing means of the alarm. In the specific embodiment shown in Figure I at least part of the sensing means is in contact with or is very close to part of the base of part 3 of the seat so that any deformation of the seat which may occur when a load is placed upon it will be transferred to the sensing means.

Figure 2 shows the detail of the hollow tube 6 which may be made of plastics material.

Within the tube 6 is a fixed metal contact 10 and a movable metal contact II.

The fixed metal contact 10 is disposed towards a first end 12 of the hollow tube 6 and is connected to the connecting wire 8 which passes out of the end 12 through an aperture therein.

The movable contact 11 is provided at an end of a piston 13 which pis on has a rod 14 which partly protrudes from an end 15 of the hollow tube which end is opposite to the end 12. The piston 13 is movable longitudinally within the hollow interior of the tube 6 and is urged towards the contact 10 by spring means 16 which acts between the piston 13 and the end of the tube 15.

The resilient members 7 and 17 are attached respectively to the first end 12 of the tube 6 and to an end of the rod 14 of the piston and they tend to pull the piston 13 and the fixed contact 10 mutually apart. In the absence of a load upon the seat however the action of the spring means 16 overcomes the action of the resilient members 7 and 17 so that the contacts 10 and 11 are mutually in contact.

Figure 3 shows the condition of the tube when a load is placed upon the seat 3.

Under these conditions the seat deforms and the resilient members 7 and 17 also deform, and, if the load exceeds a certain value, the force exerted by the resilient member overcomes the force exerted by the spring means 16 such that the end 12 of the tube and the rod 14 of the piston are pulled mutually apart.

The point at which the piston 13 is drawn backwards against the action of spring 16 in the hollow tube 6 is dependent upon the relative strengths of the spring 16 and the resilient members 7 and 17 and upon the load placed upon the seat 3 which determines the degree of deformation of the resilient members.

The alarm comprises the sensing means which responds to a load placed upon the seat and signalling means (not shown) which alerts a person in the vicinity of the vehicle to the presence of an intruder.

The signalling means may comprise audible signalling means such as a siren, bell, or buzzer, and/or a visual signalling means such as a flashing light.

The alarm may be set in an activated condition when the owner or user of the car wishes to park the vehicle and leave it for a period of time. When the alarm is activated the signalling means may be actuated by electrical signals from a power source.

Indicator means may be provided e.g. in the dashboard of the vehicle, to inform a user that the alarm has been activated.

In the absence of any load upon the seat 3 the contacts 10 and 11 are in mutual contact and form an electrical circuit which prevents electrical signals from the power source from actuating the signalling means, but when a load is placed upon the seat 3 which load is sufficient to cause the contacts 10 and I 1 to be drawn apart the circuit is broken and electrical signals from the power source actuate the signalling means.

If an intruder in the car tries to deactivate the alarm by cutting the connecting wires 8 or 9 then the circuit will be broken and the signalling means will be actuated.

In order to protect the resilient means 7 and 17 they may be concealed behind suitable guards attached to an underside of the seat.

Alternatively, in a different embodiment of the invention, the sensing means as a whole may be concealed within the upholstery of the part 3 of the seat.

The device may be fitted to the seat in a motor car as an accessory or it may be built into the seat when the seat is manufactured.

Clearly it is possible to select the resilient members and spring means so as to produce divergence of the contacts in response to any selected load.

This will ensure that the sensing means is responsive to a load produced by an intruder seating, kneeling, or leaning on the seat but is not responsive to the presence of lighter items such as bags or cases which may be left on the seat.

It will be appreciated that this kind of alarm may be used in addition to other kinds of alarms already commercially available which respond to opening of a door of the vehicle or rocking or tilting of the vehicle.

It will also be understood that a similar kind of sensing means could be attached to or incorporated in the backrest 2 of a seat.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method of process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAI MS:

I. A method of indicating an unauthorised attempt to use a motor vehicle, wherein an alarm device is activated in response to application of a load to a seat of the vehicle.
2. A method according to Claim I wherein there is provided a detection circuit, including a pair of electrical contacts, and wherein said contacts are operated by movement of a part of the seat relative to a floor of the vehicle.
3. A motor vehicle having a seat and sensing means responsive to application of a load to the seat to provide an alarm signal.
4. A vehicle according to Claim 3 wherein the sensing means is responsive to movement of a part of the seat relative to a floor of the vehicle.
5. A sensing means for use in a vehicle according to Claim 4 and comprising an electrically insulating tube, an electrical contact disposed in and fixed with respect to the tube, a movable contact which is slidable along the interior of the tube to and from the fixed contact, a resilient element for urging the movable contact towards the fixed contact, electrically conductive leads extending from the contacts and respective elongated elements anchored with respect to respective ones of the electrical contacts.
6. Sensing means according to Claim 5 wherein each of said elongated elements comprises a respective tension spring.
7. In or for a vehicle alarm device, sensing means substantially as herein described with reference to and as illustrated in the accompanying drawing.
8. Any novel feature or novel combination of features disclosed herein or in the accompanying drawing.