Patent ID: 8156655
Filing Date: 2012-04-17
Classification: B23D

Abstract:
1. A pneumatically powered pole saw, comprising: an extendable pole; a head member secured to the extendable pole; a cutting blade movably mounted to the head member; a piston linked to the cutting blade, the piston being slidably received within a piston chamber of the head member; a reciprocating valve disposed in the head member, the reciprocating valve being configured for movement between a first position and a second position wherein the reciprocating valve releases a portion of a source of compressed gas into the piston chamber on one side of the piston when the reciprocating valve is in the first position causing the cutting blade to move in a first cutting direction towards a limit of travel in the first cutting direction and a first check valve provides fluid communication to the piston chamber on another side of the piston causing the reciprocating valve to move from the first position towards the second position, when the cutting blade reaches the limit of travel in the first direction, the reciprocating valve releases another portion of the source of compressed gas into the piston chamber on the another side of the piston when the reciprocating valve is in the second position causing the cutting blade to move in a second cutting direction opposite to the first cutting direction and towards a limit of travel in the second cutting direction and a second check valve provides fluid communication to the piston chamber on the one side of the piston, the reciprocating valve moving from the second position towards the first position when the cutting blade reaches a limit of travel in the second direction, wherein the reciprocating valve comprises an actuator on either side of the reciprocating valve and a portion of the cutting blade is slidably received on an assembly between a first stop member and a second stop member fixed to the assembly, the assembly being slidably mounted in the head member, wherein contact of the portion of the cutting blade with either the first stop member or the second stop member causes the assembly to move and contact the actuator on either side of the reciprocating valve moving the reciprocating valve between the first position and the second position.