Patent ID: 6935850

Claim:
A dual-direction pump comprising: a head portion forming two inlet ports to each of which a cylinder is coupled, each inlet forming an inlet duct and an inlet channel in fluid communication with each other, the inlet duct having a bottom in which a plurality of first grooves are defined and in fluid communication with the inlet channel for allowing air to enter the inlet channel therethrough, the head portion forming an outlet port in which an outlet channel is defined and in fluid communication with the inlet channel; an inlet return-flow prevention device comprising an inlet valve seat mounted to the inlet duct and a valve piece movably received inside the inlet duct and between the bottom of the inlet duct and the inlet valve seat for selectively blocking a bore defined in the inlet valve seat and in fluid communication with both the inlet duct and the cylinder; a leakproof device received and retained in the inlet port and between the inlet duct and the cylinder; an outlet return-flow prevention device comprising an outlet valve seat attached to the outlet port of the head portion and forming a space between a bottom of the outlet valve seat and the outlet port and a valve piece received in the space and movable between the bottom of the outlet valve seat and the outlet port to selectively block the outlet channel of the head portion, the outlet valve seat forming an outlet bore in fluid communication with the space and adapted to form fluid communication with an external inflation valve, a plurality of second grooves being formed on the bottom of the outlet valve seat and in fluid communication with the outlet bore for allowing air to enter the bore therethrough; and a knob rotatably mounted to the outlet valve seat and forming threading for selectively and releasably engaging the external inflation valve.