US 4,569,263 AGranted

Method and apparatus for fine shearing

AssigneeFoley-Belsaw Company

InventorMordko L. Kravets

Life of this patent

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Abstract

A method and apparatus for fine shearing a metal workpiece involves placing the workpiece on a stationary die surface for support and driving a single punch against the workpiece such that at least a portion of the workpiece is placed in compression. The punch is then driven into and through the workpiece along a predetermined path which has a first directional component both perpendicular to and directed toward the die surface and a second directional component both parallel to the die surface and directed into the compressed portion of the workpiece. The punch is driven with a force having components both perpendicular to and parallel to the path of the punch. The force component perpendicular to the punch path is large enough to keep the compressed portion of the workpiece in a plastic state. The force component parallel to the path of the punch is large enough to overcome the shear strength of the workpiece along the path. The method and apparatus allow the formation of a variety of fine-sheared surface configurations.

Claims18

Dependent claims

A method of fine shearing a workpiece which comprises:

(a) placing the workpiece on a working surface of a stationary die, leaving an exposed surface on the workpiece;
(b) approaching the exposed surface of the workpiece with a moving tool having a compression surface with a cutting edge such that at least a portion of the compression surface of the tool and the working surface of the die overlap when the tool first contacts the workpiece;
(c) driving the compression surface of the tool against the exposed surface of the workpiece with a force having a component perpendicular to the working surface of the stationary die to put a portion of the workpiece in compression between the tool and the die while keeping both the die and workpiece stationary;
(d) while continuing to keep the die and workpiece stationary, driving the tool along a predetermined path into and through at least a portion of the workpiece, said path having a first directional component both perpendicular to and directed toward the die working surface and also simultaneously a second directional component both parallel to the die working surface and directed toward the compressed portion of the workpiece, the force with which the tool is driven having components both perpendicular and parallel to the path or the tool, the force component perpendicular to the path of the tool being large enough to keep that portion of the workpiece which is compressed between the tool and the die in a plastic state and the force component parallel to the path of the tool being large enough to overcome the shear strength of the workpiece at the cutting edge.

1 more element

An apparatus for fine shearing a workpiece comprising:

(a) a movable punch having a compression surface with a cutting edge;
(b) a stationary die means for supporting the workpiece on a working surface while leaving an exposed surface in the area of the desired shear cut;
(c) means for driving the compression surface and cutting edge of the punch against the exposed surface of the workpiece with a force having a component perpendicular to the working surface to put a portion of the workpiece in compression between the punch and the die while keeping the die and workpiece stationary;
and
(d) means for leading and driving the punch along a predetermined path into and through at least a portion of the workpiece, said path having a first directional component both perpendicular to and directed toward the die working surface and also simultaneously a second directional component both parallel to the die working surface and directed toward the compressed portion of the workpiece, the force with which the tool is driven having components both perpendicular and parallel to the path of the tool, the force component perpendicular to the path of the tool being large enough to keep that portion of the workpiece which is compressed between the tool and die in a plastic state and the force component parallel to the path of the tool being large enough to overcome the shear strength of the workpiece at the cutting edge.

2 more elements

Dependencies are inferred from the claim text.