VEHICLE TYRE PRESSURE CHECKING

A sensor array (13) for checking the pressure of a vehicle tire while being moved over the array comprises two sets (14) and (19) of aligned, facing sensor members. The first set (14) of sensor members is formed by slits (15) cut into a plate of metal to form first fingers (16) connected in cantilevered fashion to a first base portion (17), which extend in the direction of intended vehicle movement to free ends (18). The second set (19) of sensor members is formed by slits (20) cut into a plate of metal to form second fingers (21) connected in cantilevered fashion to a second base portion (22), which extend in the reverse of the direction of intended vehicle movement to free ends (23). The fingers of the two sets are aligned and the free ends (18) and (23) are closely adjacent. Each finger is provided with a load sensing system (28, 29) which provides an indication of the load on the finger as the tire moves over the finger. Loads are applied to different positions along the fingers as the tire moves over the array. The sensitivity of the array increases from a minimum for a load applied where the first fingers (16) are attached to the first base portion (17), to a maximum adjacent the free ends (18, 23) of the first and second fingers (16) and (21), and then decreases to a minimum where the second fingers (21) are attached to the second base portion (22). The fingers may be replaced by series of individual sensing elements (42) arranged in groups so as to constitute sensor members, whose outputs are weighted so that the sensitivity varies in a similar manner along a sensor member.