US4156538A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cross-linked plastic book covers
Assignee: Bookwrights Inc
•
Filing: 1977-01-31
•
Granted: 1979-05-29
•
Expires: 1997-01-31
Abstract
Abstract This method makes plastic book covers which have stiffer front and back panels and which have diminished plasticizer migration between the cover and any contacting cover or other adjacent surface. The covers are cross-linked to a limited extent to improve the elasticity of the hinge lines; and to a greater extent at the back and front cover areas to add stiffness to the plastic material. Laminated plastic covers are made with the different layers made of material that responds to cross-linking chemicals or radiation to different degrees, The covers can be made of expanded plastic and laminates.
Inventors
- 👤 Alvin V. Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:51
CPC Classifications
B; B42; B42C; B42C7/00; B42D; B42D3/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
238 words
The method of making a book cover having front and back cover panels connected to a spine panel along hinge lines, which method comprises: (a) forming the cover of plastic material that is thermoplastic and of a thickness and flexibility unsuitable for a book cover, because of characteristics of the material for hinge lines that connect the cover panels with the spine panel or flexibility unsuitable for the front and back panels of the cover; (b) forming hinge lines at the locations where the cover panels connect with the spine panel; (c) making the front and back cover panels stiffer than other parts of the cover by cross-linking them by irradiation to a greater degree than the other parts of the cover to make the front and back panels stiff enough to be suitable for book covers, and maintaining the irradiation of the front and back panels for a sufficient time to diminish migration, of any plasticizer in the plastic, between the cover and a second cover or other plastic surface with which the cross-linked cover comes in contact; and (d) selectively exposing the hinge lines of the cover by shielding means that limit the irradiation to a lesser dosage than that of the cover panels, and limiting the exposure of the hinge lines to a period that will improve the hinge life of the hinge lines without excessive stiffening of the plastic material of the hinge lines.
Claim 2
Independent Claim
238 words
The method of making a book cover having front and back cover panels connected to a spine panel along hinge lines, which method comprises: (a) forming the cover of plastic material that is thermoplastic and of a thickness and flexibility unsuitable for a book cover, because of characteristics of the material for hinge lines that connect the cover panels with the spine panel or flexibility unsuitable for the front and back panels of the cover; (b) forming hinge lines at the locations where the cover panels connect with the spine panel; (c) making the front and back cover panels stiffer than other parts of the cover by cross-linking them by irradiation to a greater degree than the other parts of the cover to make the front and back panels stiff enough to be suitable for book covers, and maintaining the irradiation of the front and back panels for a sufficient time to diminish migration, of any plasticizer in the plastic, between the cover and a second cover or other plastic surface with which the cross-linked cover comes in contact; and (d) selectively exposing the hinge lines of the cover by shielding means that limit the irradiation to a lesser dosage than that of the cover panels, and limiting the exposure of the hinge lines to a period that will improve the hinge life of the hinge lines without excessive stiffening of the plastic material of the hinge lines.
Claim 3
Dependent Claim
113 words
The method described in claim 1 characterized by passing a sheet of plastic through a cut-out station, forming hinge lines in the cover area at regions where the front and back panels join a spine panel of the cover, forming a groove that outlines the cover area at the cut-out station, the groove having a depth substantially equal to the thickness of the sheet so as to serve as a tear line, and holding the cover in its original position in the sheet to maintain the cover in position during the selective cross-linking of the cover, and thereafter removing the cover, as outlined by the tear line, from the remainder of the sheet.
Claim 4
Dependent Claim
78 words
The method described in claim 1 characterized by passing a sheet of plastic material through a cut-out station, impressing the outline of the cover in the plastic sheet at the cut-out station, advancing the sheet to a crosslinking station with the area that forms the cover in its original position in the sheet to control register of the cover with apparatus that does the crosslinking, and removing the cover from the sheet after the cover has been crosslinked.
Claim 5
Dependent Claim
126 words
The method described in claim 1 characterized by making a plurality of book covers from a single sheet of thermoplastic material by advancing the sheet through a cut-out station at which hinge lines are formed by making depressions in the sheet at the sides of the front and back cover panels that are closest to one another and substantially simultaneously therewith forming a groove having a depth substantially equal to the thickness of the sheet to leave at the bottom of the groove a tear line along which the cover can be torn loose from the sheet, and leaving the tear line intact to maintain the cover in its fixed position in the sheet while advancing the sheet from the cut-out station to a cross-linking station.
Claim 6
Dependent Claim
53 words
The method described in claim 4 characterized by moving the sheet with a stop-and-go movement during the cutting out of the cover and during crosslinking thereof, forming the hinge lines and the tear line while the cover is stopped, and crosslinking the cover while it is moving as a unit with the sheet.
Claim 7
Dependent Claim
98 words
The method described in claim 1 characterized by making the cover of plastic material which is expanded at the areas of the cover that constitute the front and back panels of the cover, crosslinking the expanded plastic of the front and back panels to increase their stiffness, the greater thickness resulting from the expanded condition of the plastic causing increase in stiffness as a result of the location of portions of the expanded plastic further from any neutral axis, about which the cover panels tend to bend, as compared to unexpanded plastic of equal weight per unit area.
Claim 8
Dependent Claim
72 words
The method described in claim 1 characterized by using for the cover an unsupported, synthetic high polymer material that is heatable to a softening temperature by exposure to a dielectric field, and softening the cover material by dielectric heating, and while so heated, forming hinge line grooves in the softened material and also a groove that serves as a line of severance of the cover from the remainder of the polymer material.
Claim 9
Dependent Claim
43 words
The method described in claim 1 characterized by applying crosslinkable adhesive to the cover, applying the cover to a book filler with crosslinkable adhesive in contact with the filler, and crosslinking the adhesive after the cover and filler are assembled as a book.
References Cited (Backward Citations)
NL49933C
Cited
US2478132A
Cited
US3097150A
Cited
US3168424A
Cited
US3454694A
Cited
US3414296A
Cited
US3532363A
Cited
GB1243752A
Cited
US3904227A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-05-28 | 1982-11-27 | 1983-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-28 | 1986-11-27 | 1987-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-28 | 1990-11-27 | 1991-05-29 | $7700.00 | Window Closed / Lapsed |