US3685338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hem formation
Assignee: FREDERICK A KRAUSE ASSOCIATES Inc
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Filing: 1970-04-24
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Granted: 1972-08-22
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Expires: 1990-04-24
Abstract
Abstract Hems are formed on the edges of sheet metal objects by forcing the edge of the objects against a concavely curved forming element. This is done in a press which applies force in the plane of the sheet metal while supporting its sides against buckling.
Inventors
- 👤 Bernard L Hoffman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:28
CPC Classifications
B; B21; B21D; B21D51/00; B21D51/16; B21D51/38; B21D51/44; B21D19/00; B21D19/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
119 words
A method of forming a hem along an edge of a sheet metal object, said hem comprising a flange lying against the adjacent metal of the object, said method comprising the steps of bending said edge back against said object by pressing against said edge in the plane of the region of said object adjacent said edge with a concavely curved forming element having a radius of curvature approximately one and one half times the thickness of the metal which forms said edge, and continuing to press with said element against the bend thus formed by an amount sufficient to force said edge back along said object away from said bend, with the edge pointing away from the bend.
Claim 2
Independent Claim
119 words
A method of forming a hem along an edge of a sheet metal object, said hem comprising a flange lying against the adjacent metal of the object, said method comprising the steps of bending said edge back against said object by pressing against said edge in the plane of the region of said object adjacent said edge with a concavely curved forming element having a radius of curvature approximately one and one half times the thickness of the metal which forms said edge, and continuing to press with said element against the bend thus formed by an amount sufficient to force said edge back along said object away from said bend, with the edge pointing away from the bend.
Claim 3
Independent Claim
114 words
A method of forming a hem along the edge of a sheet metal object, said hem comprising a flange lying against the adjacent sheet metal of the object, said method comprising the steps of first forming a U-shaped bend in said metal object at a location close to its said edge whereby the edge is bent back against the adjacent metal, said U-shaped bend being formed to a major radius of approximately one and one half times the sheet metal thickness and then applying sufficient force against the base of said U-shaped bend to drive said edge back along said adjacent metal away from said bend, with said edge pointing away from said bend.
Claim 4
Independent Claim
114 words
A method of forming a hem along the edge of a sheet metal object, said hem comprising a flange lying against the adjacent sheet metal of the object, said method comprising the steps of first forming a U-shaped bend in said metal object at a location close to its said edge whereby the edge is bent back against the adjacent metal, said U-shaped bend being formed to a major radius of approximately one and one half times the sheet metal thickness and then applying sufficient force against the base of said U-shaped bend to drive said edge back along said adjacent metal away from said bend, with said edge pointing away from said bend.
Claim 5
Dependent Claim
30 words
A method as in claim 2 wherein the force applied to said base is countered by an opposing force in the leg of said U-shaped bend away from said edge.
Claim 6
Dependent Claim
17 words
A method as in claim 3 wherein said leg away from said U-shaped bend is laterally supported.
Claim 7
Dependent Claim
210 words
Apparatus for forming a hem along the edge of a sheet metal object, said apparatus comprising, means for supporting a sheet metal object in a manner such that the metal adjacent its edge lies in a fixed plane, said supporting means comprising a first support element having a supporting surface wHich lies in a first fixed plane and a second support element having a supporting surface which lies in a second fixed plane parallel to but displaced from said first fixed plane to accommodate the metal of said object, a hem forming element having a concavely curved forming surface and means operative to move said forming element along one of said fixed planes such that its said forming surface initially engages the edge a sheet metal object supported by said supporting means, the radius of curvature of said forming surface being about one and one half times the thickness between said first and second fixed planes to cause the edge of such sheet metal object to be bent back against the adjacent metal surface and, when so bent back, to face away from the bend thus formed, whereby continued movement of said forming element will produce a longer hem by urging said edge further back from the bend so formed.
Claim 8
Dependent Claim
210 words
Apparatus for forming a hem along the edge of a sheet metal object, said apparatus comprising, means for supporting a sheet metal object in a manner such that the metal adjacent its edge lies in a fixed plane, said supporting means comprising a first support element having a supporting surface wHich lies in a first fixed plane and a second support element having a supporting surface which lies in a second fixed plane parallel to but displaced from said first fixed plane to accommodate the metal of said object, a hem forming element having a concavely curved forming surface and means operative to move said forming element along one of said fixed planes such that its said forming surface initially engages the edge a sheet metal object supported by said supporting means, the radius of curvature of said forming surface being about one and one half times the thickness between said first and second fixed planes to cause the edge of such sheet metal object to be bent back against the adjacent metal surface and, when so bent back, to face away from the bend thus formed, whereby continued movement of said forming element will produce a longer hem by urging said edge further back from the bend so formed.
Claim 9
Dependent Claim
138 words
Apparatus as in claim 5 wherein said supporting means comprises a die press assembly for forming said object from flat sheet metal stock, said die press assembly including a pair of openable and closeable die shoes and pressure projectable and retractable forming elements on said shoes, means connecting said hem forming element to one of said die shoes, a lateral supporting element immediately adjacent said forming element and means mounting said lateral supporting element for projection up from said one die shoe during the formation of an object by said assembly and for retraction following such formation upon further closing of said die shoes while said hem forming element is under the direct action of said one die shoe whereby the forces applied to said object during the hem forming operation are applied directly through said die shoes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |