GB682485A - Improvements in or relating to pumps - Google Patents

Abstract

682,485. Pistons. WHITE'S TYRE PUMPS, Ltd, June 14, 1951 [Nov. 3, 1950; March 30, 1951]. Nos. 26915/50 and 7463 / 51. Class 122(i) [Also in Group XXVIII] In a manually operable air pump of the plunger and cylinder type, the plunger comprises a single block of resiliently deformable material such as a relatively soft rubber compound or sponge rubber, at least that part of the block which engages the wall of the cylinder being barrel shaped or having a spherical curvature so as to diverge from the cylinder wall on both sides of a circumferential zone of contact, the block being mounted between rigid members which are relatively axially movable to apply an adjustable axial pressure to the block and a non-return valve is provided to admit air to the cylinder during the suction stroke of the pump. A spherical block 29 is secured between washers 36, 37 engaged by the head of a bolt 33 and a nut 38 thereon, the bolt being secured to the plunger rod. A hole 34 passes through the block 29 and opens into a flat surface 31 provided by a notch 30. A flap 35 which may be secured to the block or integral therewith covers the hole 34. In a modification the block is not notched and the washer 36 is provided with a hole aligned with the hole 34 and a flap valve is mounted on the outer surface of the washer. In a further modification the suction valve comprises a flap valve mounted on the end plug of the cylinder.