In the case of presently available parking posts, there appears to be a universal acceptance of the inconveniences of using such apparatus; this includes the necessity to stop the vehicle, to get out and lower the post, using a key to remove a padlock to unlock the post, and repeating these operations after passage over the post, or after withdrawal of the vehicle from the parking space.

There have been proposals for the remote operation of parking posts and Patent Application WO 90/15901 discloses a remote control method for operating such a parking post.

Another problem with parking posts is that, if they are accidentally driven into, the weight and motion of the car causes them to bend making them useless. Repeated knocks on the post can loosen the fittings and thus increase the necessity for maintenance of the post. In an extreme case the vehicle can drive into the parking post, knocking it flat and then driving over it making the post useless.

We have now devised an improved vehicle barrier such as a parking post which reduces these problems.

According to the invention there is provided a vehicle barrier comprising (i) a base plate to be secured to a surface; (ii) a post connected to the base plate so the post is movable relative to the base plate between a lowered, passage-permitting position, and a raised passage-barring position; (iii) a locking means able to lock the post to the base plate in the raised passage-barring position and (iv) a vehicle impeding means

and, in which barrier, when the post is in its locked raised position and is subjected to a sideways force sufficient to move the post away from its raised position so as not to act as a vehicle barrier, the vehicle impeding means operates to act as a vehicle barrier.

In operation by a user the post is unlocked from the base plate and is lowered and raised, preferably by remote control, and so moves relative to the base plate so that when the post is lowered a vehicle can be driven over the post.

In use, preferably the base plate is connected to a surface plate which surface plate is attached to the ground surface, e. g. by means of bolts set in concrete.

Preferably the base plate operates as the vehicle impeding means so that, if the post is subjected to a sideways force sufficient to move the post when the post is locked to the base plate, so that the post no longer acts as a vehicle barrier, the base plate is moved with the post and the base plate will project sufficiently from the ground to act as a vehicle barrier. Alternatively there can be spikes or other known vehicle impeding means which are below the surface but when the post is knocked over they automatically come into effect.

Preferably the base plate is held to the ground or the surface plate by a spring means.

Preferably the spring means is strong enough not to be moved by hand; however, if it is driven into by a car or other vehicle from any direction and thus subjected to a sideways force the post and barrier will move sideways.

If the post is pushed right over, it will still be impossible to drive over it as the base plate remains attached and locked to the bottom of the post, so that when it is pushed flat the height of this plate would be too high to drive over. As the vehicle moves away from the post, the post and base plate will return to their original position with the post in the vertical position and remain fully operational. If this does occur,

whether by accident or design, and the post is driven into, an alarm can sound alerting the driver of the car and owner of the property. The alarm can operate remotely so that a person inside, e. g. inside a dwelling, is alerted.

Preferably the barrier arrangement works regardless of the direction in which the post is subjected to a force.

Preferably the parking post is operated by remote control and there is a motor able to unlock the locking means and raise and lower the post from its lowered to its raised position and vice versa and there are batteries within the post or under the ground connected to a controller so that, on receipt of a signal, e. g. radio, infra red, ultra <BR> <BR> sound etc. , the motor operates so that the post is operated. The motor and its control preferably have switches which operate automatically to limit the movement of the post so that it does not overrun or overload the motor. These switches can be in the form of micro-switches, e. g. tilt switches.

In use there can be a transmitter on the vehicle and, by pressing a button on a transmitter in the vehicle of a permitted user, the post will lower allowing the vehicle to pass over it. With another press of the button the post will rise back to its upright position.

Preferably there are spring means within the post which operate when the post is lowered to automatically return the post to the raised passage-barring position when there is no countervailing force, e. g. when the motor is turned off. These spring means preferably comprise one or more compression springs and can also serve to control the movement of the post from its raised to its lowered position and vice versa.

In one embodiment there is a secondary compression spring attached to the base plate which is compressed as the post nears the upright position to provide automatic

braking to the post and which assists in moving the post initially when it starts to be lowered from its raised position and the forces on the motor are greatest.

As well as preventing people from parking on unauthorised property, the parking post can act as a security measure; for example, preventing people from stealing a car from a driveway.

The unit can bolt to the ground and there will be no need to run any wires to it. It can run off a battery, which can be trickle charged from a solar panel on the unit. In the event of an electrical failure a key lock can be situated on the side of the unit. This can be used to de-latch the locking means and motor, allowing the parking post to be lowered by hand. This key lock can be concealed so that it cannot be located by an unauthorised user. Optionally there can be a fan or other cooling means which can automatically operate if the battery gets too hot during charging in hot weather.

Preferably there is a mechanism whereby, when the post is moving e. g. downwards, and it hits an obstruction, the motor is stopped and optionally is reversed a small distance to back off from the obstruction.

It is a feature of the invention that, when the post is in its upright passage-barring position, there are no screws, bolts or fixing means which can be operated from outside the post so that it is not possible for these to be undone by an unauthorised user.

The invention is illustrated in the accompanying drawings which show an embodiment of the invention.

Referring to the drawings:- Fig. 1 shows one embodiment of a parking post in its raised position; Fig. 2 shows the parking post of fig. 1 in its lowered position;

Fig. 3 shows the parking post of fig. 1 when it has been struck and moved away from its raised position; Fig. 4 shows the parking post of fig. 1 flattened by an impact; Fig. 5 shows another embodiment of the invention; Fig. 6 shows a plan view of fig. 5; Fig. 7 shows a side view of the embodiment of fig. 5 and Fig. 8 shows the device of fig. 5 partly knocked over.

Referring to fig. 1, a parking post (1) is locked to a base plate (2) by a locking means (not shown) which base plate (2) is attached to a support plate (3) which support plate is fixed to the ground, e. g. by bolts embedded in concrete. There is a solar panel (4) which is connected to a battery inside the post (1); the battery is connected to a motor by a remote control switch, e. g. operated by radio, infra red or ultra sound of a particular frequency. In this upright position no vehicle can pass.

Referring to fig. 2, when a permitted user approaches, he sends out a signal to the control switch which causes the locking device to unlock and the motor to operate to lower the post about pivot point (5) to the position shown; this allows the vehicle to pass. After the vehicle has passed, the motor is reversed and the post returned to the upright position.

Referring to figs. 3 and 4, if the post is struck in any direction, the post and the base plate (2) moves about a flexible mounting so as to avoid damage and is restrained by chain (6). If the post is knocked over, e. g. by the attempt of a vehicle to drive over it, then the base plate (2) protrudes to a height'd'sufficient to prevent the vehicle from passing over it.

Referring to figs. 5 and 6, in this embodiment, a post (10) is locked to a base plate (16) by a locking device. The base plate (16) is mounted on support plate (15) fixed to the ground, e. g. by bolts set in concrete. Inside the post (10) are two compression

springs (11). There is a solar panel which is connected to a battery inside the post (10); the battery is connected to a motor by a remote control switch, e. g. operated by radio, infra red or ultra sound of a particular frequency. In this upright position no vehicle can pass.

The lower end of the compression springs (11) are connected to chains (12) which pass over drum (13) which is connected to the base plate (15) by mountings (18).

There is a second compression spring (17) which is compressed when the post is in the upright position.

In use, when a vehicle approaches the post, the driver sends a signal to the device causing the locking device to unlock and the motor to operate to move the post relative to the base plate (16) by rotation about drum (13) with the chains (12) passing over the drum (13) to the lowered position so the vehicle can pass. The spring (17) assists in the initial movement of the post away from the upright.

When the vehicle has passed, the procedure is reversed, the post is returned to the upright position by the action of the motor and the spring (17) helps to stop the post in the upright position in a controlled manner. There are conventional tilt switches and control systems to control the action of the motor and prevent overshooting and overload.

Referring to figs. 7 and 8, when the post is struck when it is locked to base plate (16), e. g. by the attempt of a vehicle to drive over it, the post and base plate (16) move with the chain (14) passing over the drum (13) and rotating the drum. The base plate (16) will then project upwards and prevent a vehicle from passing over it.