HIGH VELOCITY, COMBUSTION-POWERED FASTENER-DRIVING TOOL

摘要

In a combustion-powered, fastener-driving toolwith a combustion chamber, a piston chambercommunicating with the combustion chamber, a drivingpiston movable within the piston chamber between aninitial position and a terminal position, and a drivingblade mounted to the driving piston so as to beconjointly movable with the driving piston, the drivingpiston, the driving blade, and the piston chamber arearranged so that combustion in the combustion chamberimparts energy to the driving piston and the drivingblade so as to drive the driving piston and the drivingblade from the initial position toward the terminalposition with the driving blade preceding the drivingpiston, over a stroke having a length sufficient toenable the driving blade to transfer more than eighttenths of the maximum, transferable energy to afastener engaged by the driving blade as the drivingpiston and the driving blade approach the terminalposition. The piston chamber has an inner, cylindricalwall. The driving piston has an annular portion withan annular groove seating a piston ring or has twoaxially spaced, annular portions, at least one of whichhas an annular groove seating a piston ring engagingthe inner, cylindrical wall. The driving piston, thedriving blade, and the piston chamber are arranged sothat the driving piston and the driving blade areguided solely within the axial length of the drivingpiston, over at least substantially all of the stroke.