VACUUM PISTON RETENTION FOR A COMBUSTION DRIVEN FASTENER HAND TOOL

摘要

A combustion driven fastener hand tool is disclosed having a piston driven by combustion within a chamber, the piston affixed to a driver for forcing a fastener. The piston forms a retention chamber having a lower internal pressure (“vacuum”) than that of the surrounding combustion chamber when the piston is disposed in the starting position for operation of the device. The lower internal pressure of the retention chamber (generated from a previous combustion cycle) momentarily holds the piston in place such that combustion behind the piston must first increase sufficiently to overcome holding force of the retention chamber before the piston moves. Requiring build up of combustion chamber pressure before piston motion greatly improves efficiency and power of the device. Use of the vacuum retention chamber is readily tunable with proper sizing of the chamber.

主权项

1. A combustion driven fastener apparatus, comprising:
a piston disposed in a combustion chamber, the piston movable from a starting position to an end position within the combustion chamber; a driver affixed to the piston for driving a fastener as the piston moves from the starting position to the end position; and a retention chamber closed within the combustion chamber with the piston in the starting position and opened after the piston is moved from the starting position, the retention chamber having at least a first interior wall affixed to the piston and at least a second interior wall affixed to the combustion chamber.