GB191907A - Improvements in and relating to portable pumps for inflating pneumatic tyres and the like - Google Patents

Abstract

191,907. Cooper, J. F., and Industrial Rubber Products Ltd. Nov. 28, 1921. Oscillatiiig-cylinder pumps; actuating by foot power. - Portable foot pumps, of the kind in which the pump barrel and the operating pedal are pivoted respectively to the opposite ends of a base plate, and the pedal is connected between its ends to the piston rod, are arranged so that the area of the piston can he varied to suit the pressure at different stages of the compression. The pump comprises a piston 10 connected at 27 to a treadle 28, and a further annular piston 16 carried by a tube 13 which can be fixed to the pump barrel 1 so that the piston 10 is used alone, or can be fixed to the piston 10 so that the two pistons work in conjunction. In use, the two pistons are used until the delivery pressure reaches a suitable amount, and then the smaller piston is used alone to complete the operation. The tube 13 carries a block 17 and a pin on which slides a spring-influenced slotted plate 20. By rotating the tube 13, and then depressing a cam 18, the slotted plate can be engaged with lugs on the member 24 to fix the two pistons together, with lugs on the barrel to fix the tube to the barrel, or with one lug on the barrel and one on the member 24. to lock all the parts for storage. Delivery is effected through a ball-valve 5 into a two-armed passage, one branch leading to a pressure gauge 4 and the other 'branch 7 to the flexible delivery pipe.