Patent ID: 6619634
Filing Date: 2003-09-16
Classification: A63B,B60G,F16F

Abstract:
A pneumatic cylinder having an internal pump mechanism for charging the cylinder with atmospheric air comprising:a hollow cylinder body defining a cavity therein, said cylinder body having a closed end and an open end; a working piston slidably disposed within said cavity and having top and bottom ends, said top end of said working piston and said closed end of said cylinder body defining a gas chamber there between, a hollow elongate shaft having first and second ends and defining an interior portion therein, said first end being coupled to said bottom end of said working piston, said second end extending from said open end of said cylinder; a pumping piston slidably disposed within said interior portion of said shaft and having top and bottom ends, said top end of said pumping piston and said bottom end of said working piston defining a pressure adding chamber therebetween; a check device disposed on said pumping piston for preventing air from escaping said pressure adding chamber during advancement of said pumping piston into said interior portion of said shaft; a pumping rod having a first end coupled to said bottom end of said pumping piston and a second end extendable from said shaft for facilitating reciprocal movement of said pumping piston; and a one-way valve extending through said working piston for enabling air to flow into said gas chamber from said pressure adding chamber; whereby said reciprocal movement of said pumping piston within said shaft increases air pressure in said pressure adding chamber such that air flows from said pressure adding chamber to said gas chamber in said cylinder body across said one-way valve.