Patent US260842A successfully refreshed from Google Patents.
US4033003A
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US
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Head forming method
Assignee: BRILES Manufacturing
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Filing: 1975-11-07
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Granted: 1977-07-05
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Expires: 1995-11-07
Abstract
Abstract A method of providing an undercut "bowtie" slot in the head of a fastener such as a screw or bolt, and the resulting interim and final fastener products. The method consists of only two heading steps, starting with either a preform or a simple blank. In the first heading step a forming blow is applied which produces a "bowtie" shaped slot having side walls that are not undercut and a single, continuous ellipsoidal bulge projecting upwardly from the head adjacent to and substantially coextensive with each edge of the slot. In the second heading step a forming blow is applied which compresses the material of the ellipsoidal bulges down into the head to form a radiused undercut slot configuration that is continuous and substantially coextensive with the length of the slot.
Inventors
- 👤 Emilio R. Marroquin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:41
CPC Classifications
F; F16; F16B; F16B23/00; F16B23/0007; F16B23/0015; B; B21; B21K; B21K1/00; B21K1/44; B21K1/46; B21K1/463; Y; Y10; Y10S; Y10S411/00; Y10S411/919
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
190 words
A method of forming an undercut slot of "bowtie" configuration in the head of a fastener which comprises the steps of: applying a first header punch member to said head to form a primary head surface with a "bowtie"-shaped slot recessed below said surface and a single bulge of material projecting upwardly from said surface adjacent to each side of said slot, each of said bulges of material being elongated in the longitudinal direction of the slot and continuously convexly curving from a greatest height above said primary surface proximate the slot down to an intersection with said primary surface spaced from said slot, and applying a second header punch member to said head to compress said bulges of material down into the head below the level of said surface laterally displacing and forming material of the head into a single, elongated lateral bulge in each side of the slot to produce an undercut slot configuration between said lateral bulges, said curvature of each of said upwardly projecting bulges causing each of said lateral bulges to convexly curve in the direction from the bottom to the top of the slot.
Claim 2
Independent Claim
190 words
A method of forming an undercut slot of "bowtie" configuration in the head of a fastener which comprises the steps of: applying a first header punch member to said head to form a primary head surface with a "bowtie"-shaped slot recessed below said surface and a single bulge of material projecting upwardly from said surface adjacent to each side of said slot, each of said bulges of material being elongated in the longitudinal direction of the slot and continuously convexly curving from a greatest height above said primary surface proximate the slot down to an intersection with said primary surface spaced from said slot, and applying a second header punch member to said head to compress said bulges of material down into the head below the level of said surface laterally displacing and forming material of the head into a single, elongated lateral bulge in each side of the slot to produce an undercut slot configuration between said lateral bulges, said curvature of each of said upwardly projecting bulges causing each of said lateral bulges to convexly curve in the direction from the bottom to the top of the slot.
Claim 3
Dependent Claim
38 words
A method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein said first and second punch members are applied to said head in respective first and second cold heading steps.
Claim 4
Dependent Claim
38 words
A method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein said first and second punch members are applied to said head in respective first and second warm heading steps.
Claim 5
Dependent Claim
72 words
A method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein: each of said upwardly projecting bulges of material is formed by said first punch member along substantially the entire length of its respective side of said slot, and each of said lateral bulges is correspondingly formed by said second punch member along substantially the entire length of its respective side of said slot.
Claim 6
Dependent Claim
39 words
The method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein each of said upwardly projecting bulges of material is formed by said first punch member into a generally ellipsoidal configuration.
Claim 7
Dependent Claim
42 words
The method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein said slot is formed by said first punch member with a bottom which is concavely arcuate in the longitudinal direction of the slot.
Claim 8
Dependent Claim
38 words
The method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein one of said first and second punch members applies recessed part identification symbol means in said primary head surface.
Claim 9
Dependent Claim
42 words
The method of forming an undercut slot in the head of a fastener as defined in claim 7, wherein said first punch member applies said recessed part identification symbol means in said primary head surface laterally spaced from said upwardly projecting bulges.
Claim 10
Dependent Claim
47 words
The method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein at least one of said first and second punch members forms a speed dimple in said head in communication with said slot proximate the center of the slot.
Claim 11
Dependent Claim
34 words
The method of forming an undercut slot in the head of a fastener as defined in claim 9, wherein both of said first and second punch members form said speed dimple in said head.
Claim 12
Dependent Claim
38 words
The method of forming an undercut slot in the head of a fastener as defined in claim 9, wherein said first punch member forms said speed dimple at least partially in the material of said upwardly projecting bulges.
Claim 13
Dependent Claim
32 words
The method of forming an undercut slot in the head of a fastener as defined in claim 1, wherein said first punch member forms said primary head surface to a flat configuration.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-04 | 1981-01-03 | 1981-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-04 | 1985-01-03 | 1985-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-04 | 1989-01-03 | 1989-07-05 | $7700.00 | Window Closed / Lapsed |