Technical Field of the Invention

The invention relates to vehicle immobilisation, specifically a method suitable for immobilising a vehicle for law enforcement purposes. The method comprises the steps of providing a cutting means adapted to sever the inflation valve of a vehicle tyre, positioning the cutting means against, around or over the stem of the inflation valve and activating the cutting means, wherein the cutting means is positioned such that, when activated, the sealing valve of the inflation valve is removed or disrupted. In a preferred embodiment the activation step immediately follows the positioning step.

Background to the Invention

Security and law enforcement scenarios arise in which it is required to immobilise a vehicle by deflating one or more of the vehicle’s tyres. It is known to use tyre deflation devices utilizing one or more rows of spikes to pierce tyres in a controlled manner. Such devices are typically deployed against moving vehicles. Alternatively, it may be required to rapidly deflate one or more tyres of a stationary vehicle, for example to prevent a vehicle of interest from driving away. It is known for the police or security forces to use firearms to achieve tyre deflation in a stationary scenario, using specially adapted shotgun ammunition.

It is an object of the invention to provide an alternative immobilisation method.

Summary of the Invention

According to a first aspect, the invention provides a method of immobilising a target vehicle comprising the steps of:

(i) providing a cutting means adapted to sever the inflation valve of a vehicle tyre, said inflation valve comprising a stem and a sealing valve wholly or partly located within the stem,

(ii) positioning the cutting means against, around or over the stem, and (iii) activating the cutting means, wherein the cutting means is positioned such that, when activated, the sealing valve is removed or disrupted. In the method, the cutting means may sever the inflation valve wholly or partially. Either way, the inflation valve needs to be severed sufficiently to remove or disrupt the sealing valve, thereby enabling release, preferably rapid release, of air from the tyre.

Preferably, activation step (iii) immediately follows positioning step (ii). The skilled person will understand ‘immediately’ in the context of the invention. The intent is to activate the cutting means as soon as practicable after positioning the cutting means, in order to immobilise the vehicle swiftly. Typically, the cutting means is activated in 5 seconds or less following the positioning step, more preferably in 3 seconds or less and even more preferably in 1 second or less.

Prior art tyre deflation using specialist ammunition typically requires that the firearms operator approaches a target vehicle and shoots the tyre from a close distance. This method has two important disadvantages; there is a potential hazard from the shotgun ammunition and there is a risk that the appearance of a weapon and the noise of discharging ammunition may cause an escalation of the security scenario.

In the invention, a method of deflating the tyres of a stationary vehicle is provided without the use of firearms. Instead, the inflation valve of the vehicle tyre is severed in such a way as to remove or disrupt its sealing valve component. The inflation valve of a tyre is usually readily accessible, to enable the tyres to be inflated and their pressure to be checked using standard airline fittings.

A pneumatic tyre of a road vehicle typically has an inflation valve comprising a stem and a sealing valve, the stem being adapted to engage with the vehicle tyre. The sealing valve is wholly or partly located within the stem. Commonly, the stem and sealing valve are separate components of the inflation valve, configured to engage with each other by means of a joint. A typical joint is a threaded joint. One example of an inflation valve is the Schrader valve. The stem of a Schrader valve is usually a thin-walled metal tube, one end of which has a moulded rubber bung which secures the stem in the wheel. The other end of the stem has an external screw thread for a dust cap and an internal screw thread to hold a sealing valve. The sealing valve is typically a spring loaded sealing valve which is held within the stem by a short length of screw thread.

In the method of the invention, a cutting means is provided which is adapted to sever an inflation valve, preferably an inflation valve of the above-described Schrader type. The cutting means is positioned against, around or over the inflation valve such that, in use, a cutting element such as a blade provides a severing action. The cutting means is then activated to sever the inflation valve at the stem. In this way, the sealing valve is removed or disrupted so as to allow release of air, advantageously rapid release of air, from the tyre.

Usually, the sealing valve is secured to the stem by means of a joint, typically a threaded joint. The cutting means is preferably positioned at or below said joint, more preferably below said joint. Without the joint retaining the sealing valve, the sealing valve will be forced out of the stem by air pressure, thereby causing rapid tyre deflation.

The method of the invention may cause severed parts of the inflation valve and tyre debris to become hazardous projectiles, due to the rapid outrush of air through the stub of the inflation valve stem. Accordingly, the method may comprise the additional step of providing a shield or deflector so as to protect operating personnel from valve debris. The shield or deflector may be a component of the cutting means. The method may also comprise the step of donning personnel protective equipment (PPE) prior to step (iii).

Any suitable cutting means may be used to sever the inflation valve at the stem in order to remove or disrupt the sealing valve. For example, the cutting means may be based on a guillotine, scissor, rotary cutting, reciprocating chisel or reciprocating saw mechanism. A guillotine or scissor mechanism is particularly preferred because the cutting action can be quick and the cutting means can be compact and relatively simple. Moreover, a cutting means comprising a guillotine or scissor mechanism may be readily located over or around the inflation valve; in contrast, a chisel, rotary cutting or saw mechanism may need an associated guide component. The cutting means may be manually driven or power driven, for example electrically driven, pneumatically driven, explosively driven or spring loaded. A power driven mechanism may be manually triggered. Preferably, the cutting means is manually driven.

In one example, the cutting mechanism is a guillotine mechanism having a moving blade and a fixed restraint. The fixed restraint may take the form of a ring or partial ring structure at the end of a handle, and the cutting means may be adapted such that when a mechanism in the handle is compressed the moving blade is activated. The blade movement may be linear (e.g. sliding) or angular (fixed at one side and able to swing through an arc). In use, the cutting means may be positioned around or over the inflation valve such that the stem rests against or is in close proximity to the fixed restraint and protrudes orthogonally or near orthogonally from the restraint. When the cutting means is activated, the blade moves towards or across the face of the restraint, severing the inflation valve in the process.

For a scissor mechanism, there may be two blades adapted to move against each other. The blades may be curved or notched so as to retain the valve stem while it is being cut.

Blades incorporated into the cutting means preferably comprise hardened steel.

Guillotine cutters are known for clipping animal claws. The cutting means used in the invention may comprise a similar structure and mechanism, with the materials and size adapted to permit severing of a tyre inflation valve.

The cutting means may be positioned manually, for example by law enforcement personnel, or using a robotic device, preferably a remote controlled robotic device. Subsequent activation of the cutting means may be manual, robotically controlled or remote controlled. In a preferred embodiment of the invention, the cutting means is both positioned and activated manually. Manual cutting and activation is advantageous because the method is simple, quick and cheap, and safer than using specialist ammunition.

Any feature in one aspect of the invention may be applied to any other aspects of the invention, in any appropriate combination. The invention extends to a method substantially as herein described, with reference to the accompanying drawing.

In all aspects, the invention may comprise, consist essentially of, or consist of any feature or combination of features.

Brief Description of the Drawings

The invention will now be described, purely by way of example, with reference to the accompanying drawings, in which;

Figure 1 is a schematic sectional view of an inflation valve of the Schrader valve type, showing a preferred sever point in the method of the invention.

The drawing is for illustrative purposes only and is not to scale.

Detailed Description

Figure 1 is a schematic, cross sectional view of an inflation valve (1) of the Schrader valve type. The inflation valve (1 ) comprises a stem (2) and a spring loaded sealing valve (3). The sealing valve (3) is secured within stem (2) by means of threaded joint (4). One end of stem (2) is joined to tyre (6). The other end of the stem comprises exterior thread (5) for a dust cap (not shown).

Applying the method of the invention, a cutting means is provided which is able to sever inflation valve (1 ). The cutting means is placed against, around or over inflation valve (1) and positioned such that, when activated, inflation valve (1 ) is severed in plane A-A, or close to plane A-A. Plane A-A passes below, and optionally in close proximity to, threaded joint (4). Severing inflation valve (1) at this position causes damage which results in removal or disruption of sealing valve (3). This, in turn, enables release of air from tyre (6).

It will be understood that the present invention has been described above purely by way of example, and modification of detail can be made within the scope of the invention.

Moreover, the invention has been described with specific reference to law enforcement. It will be understood that this is not intended to be limiting and the invention may be used more generally. For example, the invention may be used more generally in the security field. Additional applications of the invention will occur to the skilled person.