US4595624A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Security glazing
Assignee: Post Office
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Filing: 1984-08-06
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Granted: 1986-06-17
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Expires: 2004-08-06
Abstract
Abstract A security glass which possesses substantial resistance to penetration by impact by a heavy implement and which exhibits only a small amount of spall formation is a glass flexible bonding material, e.g. polyvinylbutyral, laminate in which the layer of flexible bonding material positioned other than at the forwardmost flexible bonding material layer position possesses increased thickness. The rearmost glass layer is generally relatively thin and is preferably chemically toughened.
Inventors
- 👤 Thomas W. Greathead
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:20
CPC Classifications
C; C03; C03C; C03C27/00; C03C27/06; C03C27/10; B; B32; B32B; B32B17/00; B32B17/06; B32B17/10; B32B17/10005; B32B17/1055; B32B17/10761; B32B17/10009; B32B17/10036; B32B17/10045; B32B17/10128; B32B17/10137; E; E06; E06B; E06B5/00; E06B5/10; F; F41; F41H; F41H5/00; F41H5/02; F41H5/04; F41H5/0407; Y; Y10; Y10S; Y10S428/00; Y10S428/911; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24959; Y10T428/31504; Y10T428/31551; Y10T428/31627; Y10T428/3163
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
150 words
A security glass consisting essentially of a plurality of layers of glass of at least three thicknesses, and a plurality of layers of flexible bonding material disposed alternatingly to form a laminate of greater tensile strength than the glass; wherein a layer of the flexible bonding material possesses the greater or greatest thickness of any of the layers of flexible bonding material and is positioned such that it is not the layer of flexible bonding material which is forwardmost in relation to the direction of expected impact, and wherein said laminate includes a rearmost glass layer no more than 2 mm thick which is thinner than the glass layers forward thereof, which possesses a thickness of from 40-80% of the thickness of the next thickest glass layer and which is chemically-toughened so that said laminate substantially resists spalling from the rearmost surface when subject to impact on the frontmost surface.
Claim 2
Dependent Claim
150 words
A security glass consisting essentially of a plurality of layers of glass of at least three thicknesses, and a plurality of layers of flexible bonding material disposed alternatingly to form a laminate of greater tensile strength than the glass; wherein a layer of the flexible bonding material possesses the greater or greatest thickness of any of the layers of flexible bonding material and is positioned such that it is not the layer of flexible bonding material which is forwardmost in relation to the direction of expected impact, and wherein said laminate includes a rearmost glass layer no more than 2 mm thick which is thinner than the glass layers forward thereof, which possesses a thickness of from 40-80% of the thickness of the next thickest glass layer and which is chemically-toughened so that said laminate substantially resists spalling from the rearmost surface when subject to impact on the frontmost surface.
Claim 3
Dependent Claim
13 words
The security glass of claim 1 wherein the flexible bonding material is polyvinylbutyral.
Claim 4
Dependent Claim
33 words
The security glass of claim 1 wherein the said thickest layer of flexible bonding material has a thickness equal to at least three times that of the thinnest layer of flexible bonding material.
Claim 5
Dependent Claim
34 words
The security glass of claim 3 wherein the said thickest layer of flexible bonding material has a thickness equal to at least three times that of the next thickest layer of flexible bonding material.
Claim 6
Dependent Claim
47 words
The security glass of claim 1 wherein the laminate has a symmetrical structure with the said layer of flexible bonding material of greater or grestest thickness being centrally positioned and equal numbers of layers of glass and of flexible bonding material being positioned on either side thereof.
Claim 7
Dependent Claim
27 words
The security glass of claim 1 wherein the rearmost glass layer has a thickness of from 16% to 40% of the thickness of the thickest glass layer.
References Cited (Backward Citations)
FR732405A
Cited
DE1156971B
Cited
US3624238A
Cited
US3864204A
Cited
US4130684A
Cited
US3904460A
Cited
EP0003432A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-06-16 | 1989-12-16 | 1990-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-16 | 1993-12-16 | 1994-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-16 | 1997-12-16 | 1998-06-17 | $7700.00 | Window Closed / Lapsed |