AUTOMATICALLY BRAKING DEVICE WHEN LEAVING A PROTECTED AREA

摘要

The present invention relates to a braking device for use with a vehicle which moves along a surface, the braking device being operated by means external to the vehicle, for example an area of magnetic material, and is particularly, but not exclusively, for use with a wheeled trolley or cart to deter its removal from a designated area. The braking device comprises a first portion (1) for mounting on the vehicle, a braking portion (2) movable relative to the first portion from an inoperative position to an operative braking position in braking contact with the surface, and retaining means (13, 14) for retaining the braking portion (2) in its inoperative position. The retaining means comprises blocking means (13) and trigger means (14), the trigger means being movable between a primed position and a triggered position by passage in close proximity to the magnetic material, and, in the primed position, holding the blocking means in a blocking position preventing movement of the braking portion. In moving to its triggered position, the trigger means (14) releases the blocking means to allow it to move to its unblocking position to allow movement of the braking portion to its braking position on passage of the device past the magnetic material. To prevent inadvertent release of the braking portions, the braking portion (2) cooperates with the blocking means (13) to prevent movement of the blocking means from its blocking position to its unblocking position in the absence of the magnetic material, cooperation being released by application of a force to the braking portion or the blocking means.