Patent attributes
An air pump, including: two cylinders, a big one and a small one, which are telescopically fitted to each other. A head connects with the outlet end of the small cylinder. A pressure relief valve connects with the outlet end of the big cylinder. A first piston is fixed at the inlet end of the small cylinder and placed in the big cylinder. A first pipe, has one end fixed on the outlet end of the big cylinder, and the other passes through the first piston and placed inside the small cylinder. A first chamber with a passage communicating with the first pipe forms therein between the inside wall of the big cylinder and the outside wall of the first pipe. A second pipe, one end fixed at the outlet end of the small cylinder and communicating with the head in one-way air admission, has the other fit into the first pipe in a telescopicing way and communicating with it. A second piston, which is placed inside the small cylinder, fixes at the other end of the first pipe and the second pipe goes through it. A second chamber with a one-way passage communicates with the head and is formed therein between the inside wall of the small cylinder and the outside wall of the second pipe and between the outlet end of the small cylinder and the second piston.
