Unipunch Products, Inc.

Ralph L Weisbeck

James J Pancook

A punch assembly for punching a workpiece comprising a unitary stripper spring assembly that can be adjustably fastened to a punch. The unitary stripper spring assembly includes a threaded head which engages a threaded end of the punch so the effective length of the punch can be varied after sharpening by simply turning the unitary stripper spring assembly relative to the punch. The punch is fastened to the unitary stripper spring assembly only at the head. The unitary stripper spring assembly further includes a washer, and a telescopic retainer enclosed in a stripper spring between the head and the washer. The telescopic retainer responds to the force exerted on the punch assembly by the ram of a punching device by contracting during the punching stroke. After the punching stroke the stripper spring expands to strip the punch from the workpiece and the stripper spring assembly returns to its normal position. The unitary stripper spring assembly forms a discrete and integral mechanism independent of the punch. The punch assembly of the present invention achieves a simple one step adjustment of the effective punch length without the use of special tools or any disassembly of the unitary stripper spring assembly, even after repeated sharpening of the punch. Also, a punch guide having a retainer device for attaching the punch guide to the punch forms part of the present invention.

Punch assembly with unitary stripper spring assembly

A punch assembly including a punch member having first and second ends, a punching end on the first end of the punch member, an adjustable head on the second end of the punch member, a shoulder on the punch member intermediate the first and second ends, a punch retainer member including a shoulder engaging portion adjacent the shoulder for effectively engaging the shoulder, a stripper spring between the punch retainer member and the adjustable head, retainer shims between the shoulder engaging portion and the shoulder, and a counterbore in the punch retainer member for receiving the retainer shims, the counterbore being of a diameter which is substantially the same as the outer diameter of the retainer shims. By the use of the retainer shims, the distance between a reference point on the retainer member and the end of the punch may be maintained the same even after sharpening, with the adjustable head being adjustable to maintain the overall length of the punch assembly the same after sharpening. The retainer shims are installed without requiring disassembly of the punch assembly by merely driving the retainer shims over the punching end of the punch assembly until they seat on a reduced central portion proximate the shoulder.

Adjustable high speed punch

A press frame includes upper and lower arm portions forming a recess therebetween for receiving a workpiece that is supported by a worktable mounted on the lower arm portion. A ram housing is supported at the front of the upper arm portion and is provided with a ram punch connected to a power source for reciprocating the ram toward and away from the worktable. A swing arm is connected to the upper arm portion in the recess of the press frame by a vertical shaft and is arranged to pivot in a horizontal plane with respect to the upper arm portion with the shaft. A tool holder is releasably engaged to the end of the swing arm by a locking device and is provided with a vertical bore for receiving a punch tool. A cooperating die is supported in the worktable, and when the tool holder and the swing arm are positioned in punching position, the punching tool is vertically aligned between the ram and the die so that the tool holder vertically guides the punch tool toward and away from the die as the ram delivers an impact blow to the punch tool. A fluid actuated device rigidly retains the swing arm and the attached tool holder in punching position with respect to the die. When the swing arm is locked in punching position, the punch circuit is completed and thereafter is selectively energized either manually or automatically to initiate a punching stroke of the ram. To facilitate a tool and die change, the fluid actuated device operably releases the swing arm from engagement with the upper arm portion permitting the swing arm to pivot laterally in a horizontal plane out of punching position. The punching apparatus is rendered inoperable until the swing arm is returned to punching position with the die.

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Williamsville, NY, United States of America

Ralph L Weisbeck