Patent ID: 6119581
Filing Date: 2000-09-19
Classification: F04B

Abstract:
A hand pump comprising a cylindrical casing, said cylindrical casing having a top open side, a closed bottom side, and an air outlet at the closed bottom side, a top cover covered on the top open side of said cylindrical casing, a handle, said handle having a bottom end inserted through a center hole at said top cover into said cylindrical casing and a top end disposed outside said cylindrical casing, and a piston coupled to the bottom end of said handle and reciprocated with said handle to pump air out of said cylindrical casing through said air outlet, wherein said handle comprises multiple peripheral sides and angles defining a plurality of longitudinal grooves equiangularly spaced around the periphery thereof for guiding outside air into said cylindrical casing evenly at different sides through the center hole at said top cover upon an up stroke of said handle wherein two adjacent grooves of the equiangularly spaced grooves have a spacing of less then 180 degrees.