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US 4,502,222 AGranted
Shears for cutting sheet metal
AssigneeMichael P. Breston
InventorClaud B. Sargent
Life of this patent
Estimating the term…
Abstract
The shears have two levers pivoted together, each having a cutting edge at the forward end thereof and an operating handle at the rear end thereof. The lower lever has a hinge hub forming a bearing surface which is laterally offset with respect to its cutting edge and which projects forwardly and upwardly toward its cutting edge.
Claims4
Shears for cutting sheet material, comprising:
- (1) a lower lever of unitary and integral construction and having:
- (a) a blade having a cutting edge;
- (b) a front surface;
- (c) a back shear surface;
- (d) an end surface which tapers rearwardly from said shear surface toward said front surface to enable said shears to swing to the left for cutting a leftward curve in said material;
- and
- (e) a hinge hub which is laterally offset with respect to said cutting edge, said hub including a lower leg, and an intermediate center portion defining a transverse pivot bore and a planar bearing surface;
- (2) an upper lever of unitary and integral construction and having:
- (a) a blade having a cutting edge, a hinge hub extending rearwardly from said cutting edge and defining a transverse pivot bore and a bearing surface;
- and
- (b) said blade, said hinge hub, and said handle all being substantially in longitudinal alignment;
- and
- (3) a pivot extending through said bores for pivotably interconnecting said upper and lower levers.
10 more elements
Shears for cutting sheet material, comprising:
- (1) a lower lever of unitary and integral construction and having:
- (a) a blade having a cutting edge;
- (b) a front surface which includes:
- a top straight portion sloping donwardly and outwardly from said cutting edge, followed by a curved portion of a relatively large radius, followed by a curved portion of a relatively smaller radius, and followed by an inwardly-tapering curved portion;
- (c) a back shear surface which intersects said curved portion;
- (d) an end surface which tapers rearwardly from said shear surface toward said front surface to enable said shears to swing to the left for cutting a leftward curve in said material;
- (e) a hinge hub which is laterally offset with respect to said cutting edge, said hub including a lower leg which extends upwardly and forwardly from a plane containing said cutting edge, an intermediate center portion defining a transverse pivot bore and a planar bearing surface, an upper leg which extends upwardly and rearwardly from said intermediate center portion;
- and a handle extending rearwardly and upwardly from said upper leg;
- and
- (f) a narrow shoulder between said blade and said hub;
- (2) an upper lever of unitary and integral construction and having:
- (a) a blade having a cutting edge, a hinge hub extending rearwardly from said cutting edge and defining a transverse pivot bore and a bearing surface;
- (b) a handle extending rearwardly of said hinge hub;
- (c) said blade, said hinge hub, and said handle all being substantially in longitudinal alignment;
- and
- (d) said hub and said handle defining a continuous bottom surface which gradually tapers downwardly and inwardly away from said shear surface to enable said shears to swing to the right for cutting a rightward curve in said material;
- and
- (3) a pivot extending through said bores for pivotably interconnecting said upper and lower levers.
15 more elements
Dependencies are inferred from the claim text.