GB966853A - Pneumatic operating device - Google Patents

Abstract

966,853. Controlling vehicles. DUNLOP RUBBER CO. Ltd. Jan. 19, 1961 [Feb. 3 1960], No. 3769/60. Heading B7H. [Also in Division F1] A pneumatic device for operating a carburetter throttle arm, for example, comprises a deformable pneumatic operating unit, means to transmit air pressure generated in the unit by deformation thereof to a unit for actuating the throttle arm, and valve means arranged to be held open by the unit in the undeformed state thereof to permit communication between the interior of the unit and atmosphere, the valve means being arranged to close on deformation of the unit to seal the interior from atmosphere. As described, the operating unit is foot operable and consists of a moulded sac 2, Fig. 1, e.g. of rubber mounted air-tightly on a base-plate 3, the latter having an air vent 17 therein and a circular ridge 16 acting as a valve seat for cooperation with an annular impermeable rubber diaphragm 18 to seal the interior of the unit; the diaphragm 18 is normally held away from the ridge 16 by a tension cord 28, e.g. of nylon, and has holes 27 therein communicating with a tube 13 for receiving the end of a flexible pipe (not shown) leading to a tubular member 47 of the actuating unit, Fig. 2. The latter consists of a cylindrical metal body 32 in which is slidably disposed a spring-loaded plunger 40 provided with a rod 41 for coupling to the carburetter throttle arm, a rolling lobe rubber diaphragm 38 being air-tightly sealed to the body 32 and to the plunger 40. In alternative constructions, not shown in the drawings, the operating unit may comprise bellows or a diaphragm, and the actuating unit may comprise a coiled, flat, narrow-section pneumatic chamber connected at its inner end to the throttle spindle in such a manner that as the chamber is inflated it tends to open out and rotate the spindle, or the actuating unit may comprise a flat, narrow-section pneumatic chamber associated with a part-circular guide, the throttle spindle being provided with a roller co-operating with the chamber and the guide so that as the chamber is inflated the roller is pushed along the guide to rotate the spindle.