GB189642A - Improvements in air pumps - Google Patents

Abstract

189,642. Bristol Pneumatic Tools, Ltd., and Leader, H. Nov. 22, 1921. Actuating pumps by foot power.-A pump comprises a pair of cylinders oppositely disposed in line, their instrokes being effected by foot lever and link mechanism and their outstrokes by a spring. In the pump shown, the cylinders 1, 2 are formed at the ends of a tube 3 secured on a base 6 and cut away at the top to receive pairs of parallel links 32, 33 pivoted to the pistons and connected together and to the foot lever 40 by a pin 46. Valve chambers 9, 10 are provided at the cylinder ends, and are connected by a pipe 11 passing through stuffing-boxes 12, 13 in the pistons and through partitions 15, in the end castings. The ends of the pipe are secured by nuts 17 and washers 18, the latter being held by springs against perforations 19 in the partitions and constituting valves. The chamber 10 is closed, and the chamber 9 formed with an outlet connection 22 and a pressure gauge connection 25. The pistons are provided with cupleathers having flanged centres entering the stuffing-boxes 12, 13. The return spring 38 is anchored to the ends of the links 32, 33. Catches 49 hold the foot lever down when the pump is out of use. In modifications, the links 32, 33 may be formed as single members with forked ends; one member may be jointed to an extension of the other which is jointed to the foot lever: or the links may be separately connected at different points to the foot lever. Stops on the links may restrict the piston strokes.