Patent US3724305A successfully refreshed from Google Patents.
US3724305A
Expired / Lapsed
US
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Precision shearing method
Assignee: Individual
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Filing: 1970-11-04
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Granted: 1973-04-03
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Expires: 1990-11-04
Abstract
Abstract A precision shearing method which uses a pair of shearing die tools having contours corresponding to that of the article to be obtained, one of the tools being of a conventional design and the other tool being stepped to form clearances thereon which are positive and negative or zero with respect to said first tool, comprising urging the latter tool toward the work thereby causing first the positive clearance and then the negative clearance or zero clearance to act upon the work material.
Inventors
- 👤 K Kondo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:13
CPC Classifications
B; B21; B21D; B21D28/00; B21D28/02; B21D28/16; Y; Y10; Y10T; Y10T83/00; Y10T83/04; Y10T83/0405; Y10T83/06; Y10T83/869; Y10T83/8821; Y10T83/8828; Y10T83/8831; Y10T83/8832; Y10T83/929; Y10T83/9411; Y10T83/9423; Y10T83/9428; Y10T83/9432
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
166 words
A precision shearing method for the cutting of parts in a punch and die tool comprising the steps of: compressing in the tool at least the marginal area of the stock which is to be removed from the part to be produced; advancing a primary cutting edge in relative motion against an opposing precision cutting edge with a circumferential clearance therebetween, whereby the precision cutting edge creates the sheared surface on the part; advancing simultaneously against the same precision cutting edge a secondary cutting edge which is radially and axially offset relative to the primary cutting edge so as to present no circumferential clearance to the precision cutting edge and to be axially more distant from it from the primary cutting edge; and terminating the relative advance of the primary and secondary cutting edges against the opposing precision cutting edge, as soon as the secondary cutting edge is positioned in near proximity to the precision cutting edge, while the primary cutting edge axially overlaps the same.
Claim 2
Dependent Claim
166 words
A precision shearing method for the cutting of parts in a punch and die tool comprising the steps of: compressing in the tool at least the marginal area of the stock which is to be removed from the part to be produced; advancing a primary cutting edge in relative motion against an opposing precision cutting edge with a circumferential clearance therebetween, whereby the precision cutting edge creates the sheared surface on the part; advancing simultaneously against the same precision cutting edge a secondary cutting edge which is radially and axially offset relative to the primary cutting edge so as to present no circumferential clearance to the precision cutting edge and to be axially more distant from it from the primary cutting edge; and terminating the relative advance of the primary and secondary cutting edges against the opposing precision cutting edge, as soon as the secondary cutting edge is positioned in near proximity to the precision cutting edge, while the primary cutting edge axially overlaps the same.
Claim 3
Dependent Claim
57 words
A method as defined in claim 1, wherein the steps of advancing a primary and secondary cutting edge against an opposing precision cutting edge involve an axial succession of the primary and secondary cutting edges which is so spaced in relation to the ductility and thickness of the stock that compression is maintained in the shear region.
Claim 4
Dependent Claim
34 words
A method as defined in claim 2, wherein the step of advancing a secondary cutting edge involves a cutting edge which presents a circumferential overlap or negative clearance to the opposing precision cutting edge.
Claim 5
Dependent Claim
30 words
A method as defined in claim 2, further comprising the step of compressing in the tool at least the margin of that stock area which is to become the part.
Claim 6
Dependent Claim
144 words
A precision shearing tool for blanking and/or punching operations in the production of parts, comprising in combination: a die tool; a guided punch tool which moves relative to and in alignment with the die; and means for compressing the stock of the part in the region of intended shearing; the die and punch tools cooperating with one another to form three opposing cutting edges: a precision cutting edge on the one tool which is to create the precision-sheared surface on the part, and a primary and secondary cutting edges on the opposing tool which are so arranged that the primary cutting edge moves with a circumferential clearance relative to the precision cutting edge and the secondary cutting edge moves without circumferential clearance relative thereto, the secondary cUtting edge being axially recessed from the primary cutting edge in relation to the opposing precision cutting edge.
Claim 7
Dependent Claim
144 words
A precision shearing tool for blanking and/or punching operations in the production of parts, comprising in combination: a die tool; a guided punch tool which moves relative to and in alignment with the die; and means for compressing the stock of the part in the region of intended shearing; the die and punch tools cooperating with one another to form three opposing cutting edges: a precision cutting edge on the one tool which is to create the precision-sheared surface on the part, and a primary and secondary cutting edges on the opposing tool which are so arranged that the primary cutting edge moves with a circumferential clearance relative to the precision cutting edge and the secondary cutting edge moves without circumferential clearance relative thereto, the secondary cUtting edge being axially recessed from the primary cutting edge in relation to the opposing precision cutting edge.
Claim 8
Dependent Claim
38 words
A tool as defined in claim 5, wherein the secondary cutting edge on the opposing tool is so arranged that it and the precision cutting edge move with a circumferential overlap or negative clearance relative to one another.
Claim 9
Dependent Claim
59 words
A tool as defined in claim 5, wherein the primary and secondary cutting edges are part of a cross sectional tool configuration which includes a first peripheral face at a right angle to the cutting plane defined by the primary cutting edge, an axially recessed shoulder, and a second peripheral face which represents the periphery of the tool itself.
Claim 10
Dependent Claim
26 words
A tool as defined in claim 7, wherein the axially recessed shoulder of the tool configuration presents a face which is parallel to the cutting plane.
Claim 11
Dependent Claim
51 words
A tool as defined in claim 5, wherein: the tool is a socalled blanking tool which creates the outer contour of a part by cutting it out of flat stock, and wherein: the die tool carries the precision cutting edge and the punch tool carries the primary and secondary cutting edge.
Claim 12
Dependent Claim
46 words
A tool as defined in claim 9, wherein the blanking tool is designed to cut a part whose contour includes concave curvature portions; and the punch tool which carries the primary and secondary cutting edges has the secondary cutting edge omitted in the concave curvature portions.
Claim 13
Dependent Claim
52 words
A tool as defined in claim 5, wherein: the tool is a socalled piercing tool which creates an inner contour in a part by punching out a portion of the stock, and wherein: the punch tool carries the precision cutting edge and the die tool carries the primary and secondary cutting edges.
References Cited (Backward Citations)
GB190113143A
Cited
US2419862A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |