Field ^• of-the invention

This invention relates to a road blocker, i.e. a barrier which can be raised from a road surface to present a step of sufficient height to prevent ready passage of a vehicle. ^" ' Such road blockers are commonly in use, for example, at the exits of car parks.

Background-to-the invention

Conventional road blockers are expensive to install, requiring the provision of a pit in the road surface to receive the mechanism and the connection underground of a mains power supply for operating the mechanism. It is an object of the invention to provide a road blocker capable of simpler and less expensive installation.

The invention

According to the invention there is provided a generally rectangular tray with upstanding peripheral walls at least at the rear and sides, at least one cover member pivotally mounted to the tray to be movable between a lowered inoperative position for a vehicle to drive thereover and a raised operative position upstanding from the tray, and means within the tray for moving the at least one cover member between the inoperative and operative positions, the at least one cover member when in its operative position creating a step of sufficient height

- 2 - substantially to prevent vehicle passage thereover.

According to the present invention, two cover members are provided, namely a first cover member pivotted to the rear of the tray and a second cover member pivotted to the forward edge of the first cover member, whereby in the operative position said cover members create a step in the form of an inverted Vee upstanding from the tray.

The means for moving the cover members preferably acts on the first cover member and may comprise a pneumatic or more preferably an hydraulic ram acting between the tray and said first cover member. While two or more such rams acting in parallel may be employed, the use of a single ram is preferred.

It is a feature of the invention that the ram may be powered from a motor which is itself powered from a low voltage supply or possibly a trickle charged battery. The fact that only a low voltage power supply can be employed means that low voltage supply cable' can be used, which does not have to be buried relatively deeply underground. The possible use of a battery source means that the road blocker can readily be installed as a temporary measure, for example at the entrance/exit of a temporary car park.

Preferably, the battery is trickle charged by mains electricity supplied via charging means comprising a first step down transformer adapted to be connected to a mains electricity power supply; a second step,down transformer adapted to be connected to the first transformer and rectifying means for connection between the second transformer and battery, wherein, in use, the yoltage of the electricity supplied to the battery is reduced by the

first transformer to a magnitude intermediate that of the mains voltage and the required voltage for charging the battery, and is then further reduced from the intermediate magnitude to a magnitude corresponding to the required charging voltage before being fed to the battery via the rectifying means.

With this arrangement, the first and second transformers may be connected by a cable which does not need to be protected (for example as by burying) as extensively as a mains cable. Furthermore, since the cable carries a higher voltage than the charging voltages electrical energy may be conveyed along the cable with less power loss than would be the case if the power was transmitted at the charging voltage.

This saving of power may be enhanced by situating the first transformer adjacent a mains connection point and the second transformer adjacent the battery so to enable the majority of the path over which power is conveyed to be covered by the cable connecting the first and second transformers.

in one example the first transformer is adapted to reduce the voltage of a 240 volt mains power supply to an intermediate voltage of 46 volts, and the second transformer is adapted to reduce the intermediate voltage to a required charging voltage of 12 volts.

Reverting to the physical construction of the road blocker, the tray preferably has upstanding triangular side walls which close off access to the interior of the tray at all times, even when the cover members are raised.

At the rear of the tray, a ramp is preferably provided extending from the top of the rear wall of the tray, where the first cover member is pivotally mounted, down to the ground. However, at the front of the tray, the front edge of the second cover member is preferably substantially at ground level, and in its lowered position projects forwardly from the front end of the tray, rising at a small angle in the rearward direction to the level of the front edge of the first cover member, which in its lowered position is preferably substantially horizontal level with the top edge of the rear wall of the tray. Guidance for movement of the front edge of the second cover member may conveniently be provided by fixed legs projecting forwardly from the tray generally in line with its side walls, the front corners of the second cover member carrying lugs or pins or like elements which run in guides formed within said legs.

Description-of-embodiment

Further features of the road blocker in accordance with the invention will be apparent from the following description, making reference to the accompanying drawings, in which:-

Figure 1 is a perspective view of the road blocker, in a partially raised condition;

Figure 2 is a transverse cross-section through the road blocker, just inside one side wall of the tray;

Figure 3 is an internal perspective view of the road blocker, seen through a cutaway first cover

member ; and

Figures 4 and 5 show details of the road blocker in enlargement.

Referring to the drawings, the illustrated road blocker comprises a tray 10 with a uniform upstanding rear wall 12 and triangular upstanding side walls 14. Pivotally mounted as indicated at 15 to the top edge of the rear wall is a first cover member 16, and pivotally mounted as indicated at 17 to the front edge of the first cover member is a second cover member 18.

A hydraulic ram 20 can raise and lower the first cover member 16 on its pivotal mounting 15, thus also raising and lowering the second cover member 18, the forward edge of which moves backwards and forwards in front of the tray, at a level very close to ground level. For guiding the front edge of the second cover member 18, legs 22 project forwardly from the tray generally in line with the side walls thereof, these legs housing guides 24 with which cooperate pins 26 fixed to the front corners of the second cover member (see detail in Figure 5).

To the rear of the tray, a fixed ramp 28 extends downwardly to the ground from the top edge of the _ ar wall of the tray.

The transmission through which the ram 20 drives the first cover member 16 includes several folding arms 30 mounted between a rotating rod 32 at the base of the tray, and to which the lower part 40 of the folding arm is welded, and a reinforcing frame 34 on the underside of the first cover member, and to which the upper part 38 of the folding arm

is pivotted. A locking tab 36 welded to the upper part 38 of each folding arm 30 locks against the lower part 40 to keep the two parts aligned when the cover members are fully raised, whereby the locked arms prevent the first cover member from rocking end to end. This makes possible the use of the single driving ram. One such folding arm 30 is shown in the detail of Figure 4, which also shows a block 42 which is welded to the bottom of the tray to provide intermediate support for the rotating rod 32.

Referring to the second cover member 18, which is slightly inclined in its lowered position, this is provided with supports 44 of graded length which engage the bottom of the tray to reinforce the second cover member, so that it can take the weight of a vehicle passing over it.

Reference 46 in Figure 3 denotes a slip over plastics cover piece which denies finger access to the gap between the first and second cover members where they are hinged together. Moreover, reference 48 in Figure 3 denotes tie flats provided on the reinforcing frame 34, where the first cover member 16 is welded to it. In Figure 5, reference 50 refers to a pivotting washer welded to the pins 26 on the front corners of the second cover member 18 for the purpose of ensuring that the front edge of this cover member moves close to the ground, parallel to the leg 22.

Finally, in Figures 1 and 2, there are shown two inverted Vee-supports 52 and 58 for housing photocells 54 which control operation p_£ the road blocker for safety purposes.

In a modified version of the road blocker, one of the photocells 54 is replaced by a light source which emits a beam of light directed at the photo cell on the opposite VEE-support. A vehicle travelling over the road blocker (when the latter is in the inoperative position) breaks this beam and in so doing prevents the blocker operating while the vehicle is passing over the latter.