GB530189A - Improvements relating to vehicle-operated tread devices - Google Patents

Abstract

530,189. Road-traffic signalling apparatus; door-operating apparatus. CRAIG, G. L. June 20, 1939, Nos. 17979/39 and 9065/40. [Class 118 (ii)] [Also in Group XXV] Relates to a tread unit operated by the wheels of vehicles, for the purpose of actuating signals or other devices, opening and closing a gate, or closing a lighting and heating circuit when a vehicle enters a garage. According to the invention, the tread comprises a number of collapsable chambers arranged in a row extending in the direction of the travel of a vehicle, and connected to two actuating cylinders in such a way that when the chambers are compressed by the passage of the vehicle, fluid under pressure is supplied from the chambers to one or the other of the actuating cylinders according to the direction the vehicle has travelled across the tread. The tread unit consists of a number of collapsable rubber tubes 10, Fig. 1, arranged close together and parallel with one another transversely of the roadway. The tubes are connected in series with one another by pipes 12 to constitute a continuous channel, the ends of which are connected by pipes 14 to a pneumatic or hydraulic cylinder that operates, for example, a gate-operating mechanism such as that described in Specification 523,651, [Group XXV]. A vehicle wheel passing over the tread compresses and seals successive pairs of tubes and fluid is forced through the tubes, in the direction in which the vehicle is travelling, to the piston of the gate-operating mechanism or other device. Thus the gate mechanism can be made to operate differently according to the direction in which the wheel traverses the tread. A tread on both sides of the gate can be used to open and close the gate. The tubes may be composed of two rubber mouldings 18, Fig. 5, secured together by cement and by rivets 22 and stiffening strips 23. The internal corners 24 are bevelled or rounded to allow the tubes to flatten completely, and the internal surfaces are corrugated transversely, to prevent leakage of fluid past the flattened section. In a modification, the tubes 28, Fig. 7, are connected in parallel to headers 30, 32, non- return valves 34, 36 being fitted to the tubes so that liquid moves in one direction only, the tubes being refilled with liquid from a reservoir 64 after the passage of a vehicle. The liquid passes to the gate-operating mechanism through pipes 44, 46 controlled by a valve 42 which is moved in one direction or the other by two separate tubes 38, 40 placed in advance of the main tread units. The valve is moved, and the gate opened or closed, according to the order in which the tubes 38, 40 are compressed. The reservoir 64, and the connecting pipes, are dispensed with if the tubes are filled with air instead of liquid.