Duo-fast Corporation

Robert J Meyer

A pneumatically operated fastener driving tool having a pivotally mounted magazine. The displacement of the magazine is used to actuate the tool when the nosepiece is in engagement with a workpiece. With the magazine travel kept to a minimum, the magazine is coupled to a cam lever which amplifies the displacement of the magazine. One portion of the cam lever is in engagement with a trip lever which forms a bearing surface for the trigger valve cartridge, which enables the tool when the magazine is in a drive position. The geometry of the cam lever causes a relatively greater displacement of the trip lever than the displacement of the magazine. The fastener driving tool also includes a poppet valve for controlling the compressed air flow into the drive cylinder. The top portion of the poppet is subject to the compressed air reservoir within the tool. A poppet chamber disposed at the bottom of the poppet controls the opening and closing of the poppet valve. An important aspect of the invention are the throttling inlet and exhaust passageways to the poppet chamber which allow the pressure in the poppet chamber to be controlled, thus reducing poppet flutter. Another important aspect of the invention relates to a jet poppet which increases the driving force of the tool without the need to increase the tool size and also improves the tool response time.

Fastener driving tool

A pneumatically operated fastener driving tool having a pivotally mounted magazine. The displacement of the magazine is used to actuate the tool when the nosepiece is in engagement with a workpiece. With the magazine travel kept to a minimum, the magazine is coupled to a cam lever which amplifies the displacement of the magazine. One portion of the cam lever is in engagement with a trip lever which forms a bearing surface for the trigger valve cartridge, which enables the tool when the magazine is in a drive position. The geometry of the cam lever causes a relatively greater displacement of the trip lever than the displacement of the magazine. The fastener driving tool also includes a poppet valve for controlling the compressed air flow into the drive cylinder. The top portion of the poppet is subject to the compressed air reservoir within the tool. A poppet chamber disposed at the bottom of the poppet controls the opening and closing of the poppet valve. An important aspect of the invention are the throttling inlet and exhaust passageways to the poppet chamber which allow the pressure in the poppet chamber to be controlled, thus reducing poppet flutter.

Trigger valve and safety mechanism for fastener driving tool

A trigger and safety interlock feature for a fastener driving tool having a power mechanism operable in a fastener driving stroke during which a fastener is driven into a workpiece. The invention comprises a manually operable trigger movable between a rest position and a firing position, a workpiece engageable safety member movable between a standby position and an actuating position, and a control mechanism associated with the power mechanism and the trigger for initiating a drive stroke only when the trigger moves from its rest position to its firing position. The invention features an interlock configuration defined on the trigger and on the safety member for permitting the safety member to move from its standby position to its actuating position only when the trigger is in its rest position; permitting the trigger to move from its rest position to its firing position only when the safety member is in its actuating position; permitting the trigger to return from its firing position to its rest position only when the safety member is in its actuating position; and preventing the safety member from returning from its actuating position to its stand by position while the trigger is in its firing position.

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Elmwood Park, IL, United States of America

Robert J Meyer