Abstract: A pneumatic operated fastener driving device having an improved piston, which together with the cylinder form an elastic interference fit connection so that the piston is held from movement until a sufficient air pressure is applied to the piston. The piston has little or no frictional resistance with the inner surface of the cylinder during the driving or return stroke.

Abstract: A pneumatically operated fastener driving device having an adjustable staple leg length clinching mechanism and an improved actuating mechanism including a drive piston controlling valve member, a trigger member, an actuating member mounted on the trigger member and a control member.

Abstract: A drywall tool provides tactile and audible feedback to the user, as a fastener is driven by frequent multiple blows, to indicate when the fastener is properly driven, and the drywall dimpled, without tearing the paper facing of the drywall. Dimpling apparatus and a firing valve for controlling the multiple blows are described. A cam is provided to withdraw the magazine follower from the last fastener in a strip to avoid jamming or damage by a descending driver. Tool apparatus permits use of lightweight, synthetic parts.

Abstract: A pneumatic fastener applying tool featuring a self-cycling control valve with one moving port. A trigger actuated valve sets the cycling valve in motion. The cycling valve alternatively pressurizes and vents the working piston of the fastener tool. A valve stem is positioned by an integral reciprocating piston. The position of the reciprocating piston is determined by the balance of forces between a biasing spring tending to vent the working piston and a pressure-force tending to pressurize the working piston. Two flow paths, internal to the valve stem, determine the pressure applied to the reciprocating piston. One path pressurizes the reciprocating piston. Another path vents the reciprocating piston. Positive feedback of air pressure from the working cylinder positions the reciprocating piston and valve stem so as to vent the reciprocating piston when the working piston is vented and to pressurize the reciprocating piston when the working piston is pressurized.

Abstract: A pneumatic driving system for causing a nail or the like to run out of the barrel of a nailing tool to where its point may be seen by the user for lining up with a hole on the work and subsequently driving the nail into the workpiece.

Abstract: A warning system for pneumatic fastener driving tools that acceptable bumper deterioration has been exceeded thereby to warn against further use of a tool prior to replacement of the bumper. A piston carrying a driver blade moves from an upper position of rest to lower fastener driven positions. The piston sealingly engages the cylinder wall via a sealing ring. As the bumper deteriorates, the piston moves to lower and lower fastener driven positions. When the piston reaches a predetermined lower position, the effectiveness of the sealing ring is impaired, as by engagement with a notch or edge which tends to destroy or dislodge the sealing ring. This allows high pressure air to escape past the sealing ring to signal that the bumper should be replaced, as by seriously reducing the effectiveness or operability of the tool or as by producing an audible signal by the escaping high pressure air, or both.

Abstract: At the beginning of a working stroke of a compressed air loaded working piston disposed reciprocally in a pneumatic operated ramming tool said piston is initially set in motion under the action of minor amounts of compressed air until its top becomes immersed into stored compressed air and the working piston is then exposed to the full force of said stored compressed air to perform its working stroke. This working process permits to use a substantially simpler ramming apparatus.

Abstract: An actuator is provided which is respondable to control fluid pressure for moving an operative means of a valve between open and closed positions. The actuator comprises a housing defining a cylindrical bore therewithin. In one form, a shaft is carried in the housing and is engagable with the operative means. Means define first and second effective piston areas and are carried by one of the shaft and the housing and are sealingly slidable along the other of the shaft and the housing, being longitudinally movable within the cylindrical bore. The apparatus has first and second fluid chambers companionly associated with the means defining the first and second effective piston areas within the bore for yielding a differential force across the means defining the first and second effective piston areas upon increase of fluid control pressure within the actuator.