Duo-fast Corporation

Allen R Obergfell

Frank R Potucek

Raimonds Grikis

A collated fastener strip includes an elongated flexible plastic web having a row of projecting tabs along one or both of its elongated edges. Each tab is provided with an open ended slot with an opening intermediate its end in which is frictionally retained the shank of a nail or screw. The opening is of a quadrilateral configuration to provide improved frictional contact with the fastener shank. The location of the opening intermediate the ends of the slot divide the tab into two arms that can be deflected to accommodate fasteners of different sizes while retaining adequate frictional engagement therewith.

Collated fastener strip

A tool for driving fasteners includes a casing defining a nose portion and a handle portion within which is a reservoir for pressurized fluid. A driver is mounted in the nose portion that is reciprocated by a piston attached thereto and an assembly for returning the piston to a static position after a driving stroke is also included. The return assembly includes a chamber in fluid communication through an inlet with pressurized air and with an outlet that is in communication with a location beneath the return piston. A diaphragm is mounted within the chamber and is biased by pressurized fluid into sealing engagement with the inlet and the outlet. Another metered inlet is also included in the chamber that is in fluid communication with the source of pressurized fluid and controls the sealing action of the diaphragm. The chamber for the return assembly is also in fluid communication with a second chamber within which is mounted a differential area piston. The piston includes a feed pawl for feeding fasteners to the driver from a magazine. The magazine is defined by two identical portions that are reversed upon assembly. Fasteners for the tool are fed from the magazine to the driver on a tape and each fastener is held by at least one tab. To prevent the fasteners from dislodging from the tape, the tool includes a shoe biased into engagement with the fastener and the tab.

Fastener driving tool

A fastener feed assembly for a tool such as a power screwdriver having a drive member such as a rotatable bit includes a base fixed to the tool and a nose assembly slidably related to the base. The nose assembly includes a workpiece engaging surface, and when the tool is moved toward the workpiece during a fastener driving operation, the base moves toward the nose assembly. A return spring separates the base and nose assembly when the tool is withdrawn away from the workpiece. A strip of fasteners is fed from a magazine along a feed path through the nose assembly with sequential fasteners located in a drive position. Normally the drive member is spaced from a fastener in the drive position. During movement of the tool toward the workpiece in a driving operation, the drive member moves into engagement with a fastener in the drive position, and then continues to move in order to drive the fastener into the workpiece. A pawl is engageable with the strip in order to advance the strip along the feed path. During the driving operation, a feed mechanism operates in response to movement of the base toward the nose assembly to cock the pawl by moving it away from its home position along the strip away from the drive position. A lost motion arrangement delays cocking of the pawl until after secure engagement of the drive member with a fastener in the drive position. In response to withdrawal of the tool from the workpiece, the feed mechanism returns the pawl to its home position to feed an adjacent fastener of the strip to the drive position. Feed movement of the pawl is delayed until withdrawal of the drive member from the strip feed path. The strip includes a carrier with structure deformed during the drive operation for preventing reverse movement of the strip during cocking of the pawl.

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Park Ridge, IL, United States of America

Allen R Obergfell