GB2195109A

GB2195109A - Anti-theft system

Info

Publication number: GB2195109A
Application number: GB08719965A
Authority: GB
Inventors: John Harris
Original assignee: DANIEL BRIAN PETER
Current assignee: DANIEL BRIAN PETER
Priority date: 1986-09-17
Filing date: 1987-08-24
Publication date: 1988-03-30
Anticipated expiration: 2007-08-24
Also published as: GB2195109B; GB8719965D0; GB8622414D0

Abstract

There is disclosed an anti-theft system including a lock (17) which operates a valve (12) included in a fluid line (10) for a braking system of a wheeled vehicle. The lock can be operated to disenable the brake release means and may also disenable the ignition system of any engine for the vehicle. <IMAGE>

Description

SPECIFICATION Anti-theft system This invention concerns an anti-theft system for a wheeled structure of the kind (hereinafter termed "a wheeled structure of the kind referred to") having at least one ground engaging wheel, rotational movement of which can be arrested or prevented by a braking system which is dependent upon application or removal of fluid pressure for its operation.

Examples of wheeled structures of the kind referred to and for which anti-theft systems embodying the invention are particularly suited are a road haulage tractor, a trailer for same and an ordinary motor car.

Theft of wheeled structures of the kind referred to is becoming increasingly common, either for the value of goods being conveyed thereby or for the value of the structures themselves-some 30,000 for example for a typical road haulage tractor.

Devices to reduce the incidence of theft are legion, but either quite costly-involving for example a radio link with a security control centre-and therefore not widely used or somewhat simple and relatively easily defeated by the determined, experienced and professional thief.

It is an object of the present invention to provide an anti-theft system for a wheeled structure of the kind referred to but of modest cost whilst providing a high degree of protection.

According to the invention there is provided an anti-theft system for a wheeled structure of the kind referred to comprising a lock which operates a valve to maintain a required condition in a fluid line forming part of said braking system to prevent normal release of the braking system without actuation of said lock.

The lock may be a high-security key-operated lock or include a keypad requiring input of a code to enable its actuation or an infrared receiver sensitive to a coded signal from an infra-red transmitter.

The lock may, when the wheeled structure is an engine driven yehicle, also serve as an ignition enabling device.

The invention will be further apparent from the following description with reference to the single figure of the accompanying drawing, which shows, by way of example only, a diagrammatic representation of one form of antitheft device embodying same and adapted to be fitted to a road haulage tractor.

The road haulage tractor has, in known manner, a driver's cab which may be pivoted forwardly on its supporting chassis to give access to the engine and other components.

Secured to the chassis is a pneumatic line 10 servicing the braking system 11 for at least the rear wheeis of the tractor, the arrangement being such that pressure air must be supplied to the system 11 to overcome the action of springs urging brake pads against brake discs secured to the wheel axles.

The line 10 is divided to communicate with a valve 12 by way of flexible pressure hoses 13.

The valve 12 is located in the tractor cab and incorporates a mechanical plunger 14 which is reciprocable between inner and outer positions wherein the valve is opened and closed respectively.

The plunger 14 which is spring biassed to its outer position is engaged by an eccentric cam member 15 mounted on a shaft 16 which may be turned in one direction or the other, to move the plunger 14 between its inner and outer positions, by means of engagement of a suitable key 19 in a high security lock 17, such, for example, as those sold under the trade name Kaba. The security lock 17 may also serve to operate an electrical switch 18 enabling it to serve also as an ignition enabling switch for the engine of the tractor.

The lock 17 is preferably of a kind which incorporates spring means to cause ejection of the key 19 in both the "on" or "off" positions thus ensuring that the key cannot be left in the lock when the tractor is parked or when it is being driven with the risk that the brakes might be applied in error by accidental movement of the key.

In use, when the lock 17 is in an "off" position, the valve 12 is closed preventing any application of pressure air through line 10 to release the brakes, any further valve actuable by conventional control means such as a handbrake being on the side of valve 12 nearer to the pressure air source usually a small compressor driven by the tractor engine.

Turning the lock to the "on" position by use of the key opens the valve 12 restoring the braking system to its normal operating condition and, if it actuates switch 18, enables starting of the tractor engine.

A would-be thief of the tractor will find the vehicle immobile even it he is successful in starting the engine by tampering with electrical wiring. The valve 12 is inaccessibly mounted in the cab and cannot be by-passed without considerable mechanical skill and then only after raising the cab to gain access to line 10 and having suitable tools and fittings and adequate time in which to use them.

It will be appreciated that it is not intended to iimit the invention to the above example only, many variations, such as might readily occur to one skilled in the art, being possible, without departing from the scope thereof.

Thus, for example, the key-operated valve may be incorporated in the pneumatic brake line of a free-standing trailer to prevent its pick-up and transport by an unauthorised tractor driver, coupling of the trailer brake line with the tractor being to no effect without prior actuation of the valve.

Yet again, the key-operated valve may be incorporated in an hydraulic brake line of a conventional motor car. In this case the valve will be locked in a closed position to maintain pressure in the braking system to keep the brakes on.

The key-operated lock may be replaced by a digital lock operated through a key-pad into which the correct code must be keyed to enable operation or by a lock controlled by an infra-red receiver sensitive to a coded signal from a hand-held infra-red transmitter.

A number of additional "dummy" hoses and lines of similar colour may be located next to the operative ones further to frustrate the attentions of the would-be thief.

Claims

1. An anti-theft system for a wheeled structure of the kind referred to comprising a lock which operates a valve to maintain a required condition in a fluid line forming part of said braking system to prevent normal release of the braking system without actuation of said lock.

2. An anti-theft system according to claim 1, wherein said lock operates said valve by mechanical means.

3. An anti-theft system according to claim 1 or claim 2, wherein said lock also controls a switch to disenable the ignition system of any engine on the wheeled structure.

4. An anti-theft system according to any of claims 1 to 3, wherein said lock comprises a high security keyoperable lock.

5. An anti-theft system according to claim 4, wherein the lock is of the kind which bi assets. the key outwardly thereof in both the "on" and "off" positions.

6. An anti-theft system according to any of claims 1 to 3, wherein said lock is operable by means of a digital key-pad.

7. An anti-theft system according to any of claims 1 to 3, wherein said lock is controlled by an infra-red receiver sensitive to a coded signal from an infra-red transmitter.

8. An anti-theft system according to any preceding claim including "dummy" fluid lines proximate the fluid line containing said valve.