GB217520A - An improved hand-operated air pump - Google Patents

Abstract

217,520. Watkins, H. J. Dec. 31,1923. Portable hand - pumps.-A telescopic hand-pump comprises a small barrel which on being pushed into a larger barrel receives compressed air from the larger barrel while on the return stroke the air is further compressed in the small barrel and discharged through the hollow piston rod. The large barrel A is mounted on a base and contains a smaller barrel B reciprocated within it bv a handle G and moving over a piston H on a hollow rod C connected to the discharge pipe. The barrel B also carries a piston F, both pistons being fitted with check valves. The rod C is supported by a cross piece M carried by side rods D secured to a sleeve L capable of sliding tightly in the large barrel, which is closed by a cap E which is not air-tight. On the down stroke, air is compressed in the large barrel and forced through the valved piston F into the smaller cylinder; on the return stroke further compression takes place in the smaller cylinder, from which the air passes through the piston H to the discharge tube. When the pump is not in use, the tube C, &c. may be pushed in, to economize space.