US3668032A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a flexible letterpress mat
Assignee: Mccall Corp
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Filing: 1970-10-26
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Granted: 1972-06-06
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Expires: 1990-10-26
Abstract
Abstract A first portion of a sheet of thermoplastic material is placed on the face of an engraved master plate, and the plate and sheet are positioned between the platens of a hydraulic press. The first portion of the sheet and the master plate are pre-heated and are then pressed together to mold an impression of the face within the first portion of the sheet. The master plate and sheet portion are cooled while the pressure is maintained, after which the pressure is released and the sheet is shifted laterally a precise predetermined distance relative to the master plate while maintaining the angular orientation of the sheet, to position a second portion of the sheet over the face of the master plate. The steps of pre-heating, pressing, cooling and releasing are then repeated to produce a flexible mat having a pair of identical impressions in precise spaced relation and corresponding angular orientation. One or more metal layers are electrolytically deposited on the mat, and the resulting thin sheet of deposited metal is separated from the mat and laminated to a pre-curved reinforcing plate which is trimmed along its edge.
Inventors
- 👤 Charles W Bunting
- 👤 David P Groeber
- 👤 Louis W Pettlo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:03
CPC Classifications
B; B41; B41C; B41C3/00; B41C3/08; B41C3/06; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1028; Y10T156/1033; Y10T156/1039; Y10T156/1052; Y10T156/108
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
266 words
A method of making a multiple impression letterpress plate, comprising the steps of positioning a first portion of a sheet of thermoplastic material in overlying relation with an engravedlike face of a master plate, positioning said master plate and the overlying first portion of said sheet between first and second press members of a reciprocating press, preheating said master plate and said first portion of said sheet to a predetermined temperature, moving said first and second press members together to effect pressing of said first portion of said sheet with a predetermined pressure against said face of said master plate to mold an impression of said face within said first portion of said sheet, cooling said master plate and said first portion of said sheet, moving said first and second press members apart for releasing said pressure, shifting said sheet laterally a predetermined distance relative to said master plate while maintaining precise angular orientation of said sheet relative to said master plate for positioning a second portion of said sheet in overlying relation with said face of said master plate, repeating said pre-heating, pressing, cooling and releasing steps to form a mat having a pair of identical impressions in precise spaced relation and corresponding angular orientation and with each impression conforming to said face of said master plate, coating metal onto said mat to form a layer of metal corresponding to the impressions on said mat, separating said layer of metal from said mat to form a metal sheet having a corresponding pair of identical impressions, and laminating said metal sheet to a curved reinforcing plate.
Claim 2
Independent Claim
266 words
A method of making a multiple impression letterpress plate, comprising the steps of positioning a first portion of a sheet of thermoplastic material in overlying relation with an engravedlike face of a master plate, positioning said master plate and the overlying first portion of said sheet between first and second press members of a reciprocating press, preheating said master plate and said first portion of said sheet to a predetermined temperature, moving said first and second press members together to effect pressing of said first portion of said sheet with a predetermined pressure against said face of said master plate to mold an impression of said face within said first portion of said sheet, cooling said master plate and said first portion of said sheet, moving said first and second press members apart for releasing said pressure, shifting said sheet laterally a predetermined distance relative to said master plate while maintaining precise angular orientation of said sheet relative to said master plate for positioning a second portion of said sheet in overlying relation with said face of said master plate, repeating said pre-heating, pressing, cooling and releasing steps to form a mat having a pair of identical impressions in precise spaced relation and corresponding angular orientation and with each impression conforming to said face of said master plate, coating metal onto said mat to form a layer of metal corresponding to the impressions on said mat, separating said layer of metal from said mat to form a metal sheet having a corresponding pair of identical impressions, and laminating said metal sheet to a curved reinforcing plate.
Claim 3
Dependent Claim
51 words
A method as defined in claim 1 including the step of holding said sheet of thermoplastic material in light contact with said face of said master plate during said preheating by lightly pressing said second press member toward said first press member to effect said pre-heating said sheet of thermoplastic material.
Claim 4
Dependent Claim
57 words
A method as defined in claim 1 wherein said master plate and each portion of said sheet are pre-heated by circulating heating fluid through a passageway formed in said first press member, and said master plate and each portion of said sheet are cooled by circulating cooling fluid through said passageway in place of said heating fluid.
Claim 5
Dependent Claim
69 words
A method as defined in claim 1 including the steps of cooling said second portion of said thermopLastic sheet during said pre-heating, pressing and cooling of said first portion of said sheet to prevent warping of said second portion of said sheet, and cooling said first portion of said sheet while pre-heating, pressing and cooling of said second portion to prevent warping of said first portion of said sheet.
References Cited (Backward Citations)
US3532587A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |