Patent ID: 8939052
Filing Date: 2015-01-27
Classification: B23D,Y10T

Abstract:
1. A pneumatically powered pole saw comprising: a pole; a cutting blade movably mounted to the pole; a piston slidably received within a piston chamber of the pole; a piston rod coupling to the cutting blade to the piston; gas actuated main valves configured for movement between first positions and second positions wherein the gas actuated main valves are located in a main valves assembly fluidly coupled to the piston chamber; a first pilot valve configured to send actuating gas through a conduit to the main valves assembly, the actuating gas of the first pilot valve actuating the gas actuated valves of the main valves assembly to the first position, wherein movement of the main valves to the first position releases a portion of a source of gas into the piston chamber on one side of the piston while venting the opposite side of the piston chamber, and when the main valves assembly is in the first position the cutting blade to moves in a first cutting direction towards a limit of travel in the first cutting direction; and a second pilot valve configured to send actuating gas through a conduit to the main valves assembly when the limit of travel in the first cutting direction has been reached, the actuating gas of the second pilot valve causes the main valves to be moved to the second position, wherein movement of the main valves to the second position releases another portion of compressed gas into the piston chamber on the opposite side of the piston chamber and venting the one side of the piston chamber, wherein the cutting blade moves in an opposite second cutting direction with respect to the first cutting direction until a limit of travel in the second cutting direction is reached wherein the first pilot valve is again actuated and the cutting blade moves again in the first cutting direction until the limit of travel in the first cutting direction is reached.