Induction hardened blade
AssigneeStanley Black & Decker, Inc.
InventorHadyn Howells
Life of this patent
Estimating the term…
Abstract
A utility knife blade comprises a cutting edge portion and a remaining portion. The remaining portion is tempered martensite and has a first hardness. The cutting edge portion comprises a region that has been locally re-heat treated so that the microstructure in the cutting edge portion is untempered martensite having a hardness greater than the first hardness.
Claims28
A utility knife blade that is manufactured such that prior to a first use, the blade comprises:
- a unitary piece of strip steel material comprising at least about 0.9% carbon, the unitary piece of strip steel material having an integrally formed cutting edge portion and a remaining portion,
- wherein the microstructure of the steel material substantially throughout the remaining portion is tempered martensite having a first hardness,
- wherein the cutting edge portion comprises a ground acute angle, and
- wherein the cutting edge portion comprises a region that has been locally re-heat treated after the ground acute angle has been formed so that the microstructure of the steel material in the cutting edge portion is untempered martensite having a hardness greater than the first hardness.
A utility knife blade manufactured such that prior to a first use, the blade comprises:
- a steel body formed from a unitary piece of strip steel material comprising at least as much carbon as steel grade C1095, the unitary piece of strip steel material having a steel cutting edge portion and a remaining steel body portion,
- wherein the microstructure of the steel material substantially throughout the remaining portion is tempered martensite having a first hardness,
- wherein the cutting edge portion comprises a ground acute angle, and
- wherein the cutting edge portion comprises a region that has been locally re-heat treated after the ground acute angle has been formed so that the microstructure of the steel material in the cutting edge portion is untempered martensite having a hardness greater than the first hardness.
A plurality of utility knife blades formed prior to separation from each other during manufacture, the plurality of utility knife blades comprising:
- a unitary piece of strip steel material, the unitary piece of strip steel material having an integrally formed cutting edge portion formed along one edge of the unitary piece of strip steel material, and a remaining portion,
- wherein the plurality of utility knife blades are divided on the unitary piece of strip steel material by dividing marks on the unitary strip steel material that define boundaries between the plurality of utility knife blades that run transverse to a line formed by the edge of the unitary piece of strip steel material along which the cutting edge portion is formed such that each of the plurality of utility knife blades includes a portion of the cutting edge portion of the unitary piece of strip steel material,
- wherein the microstructure of the steel material substantially throughout the remaining portion is tempered martensite having a first hardness,
- wherein the cutting edge portion comprises a ground acute angle, and
- wherein the cutting edge portion comprises a region that has been locally re-heat treated after the ground acute angle has been formed so that the microstructure of the steel material in the cutting edge portion is untempered martensite having a hardness greater than the first hardness.
Dependencies are inferred from the claim text.