ELECTRICALLY HEATED WINDOW

• US 3,729,616 A
• Filed: 07/26/1971
• Issued: 04/24/1973
• Est. Priority Date: 07/26/1971
• Status: Expired due to Term

• Current Assignee: George A. Gruss, George J. Polanka, Leslie H. Pfeiler
• Original Assignee: George A. Gruss, George J. Polanka, Leslie H. Pfeiler
• Inventors: Gruss, George A., Pfeiler, Leslie H., Polanka, George J.
• Primary Examiner(s): Mayewsky, Volodymyr Y.
• Application Number:
  US05/166,064
• Time in Patent Office: 638 Days
• Field of Search: 219/522,543,544,203,213 260/73L 264/DIG.71,230,272 174/68.5,76,11PM
• US Class Current: 219/522
• CPC Class Codes: B29C 70/16 using fibres of substantial or continuous length non-woven fabrics per se D04H3/00
• CPC Class Codes: B29C 70/56 Tensioning reinforcements before or during shaping
• CPC Class Codes: B29C 70/82 Forcing wires, nets or the like partially or completely into the surface of an article, e.g. by cutting and pressing
• CPC Class Codes: B29D 23/005 provided with electrical wiring
• CPC Class Codes: B29K 2995/0005 Conductive
• CPC Class Codes: B32B 17/10385 for ohmic resistance heating
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: B32B 17/10871 in combination with particular heat treatment
• CPC Class Codes: H05B 2203/017 Manufacturing methods or apparatus for heaters
• CPC Class Codes: H05B 3/84 Heating arrangements specially adapted for transparent or reflecting areas, e.g. for demisting or de-icing windows, mirrors or vehicle windshields
• CPC Class Codes: H05B 3/86 the heating conductors being embedded in the transparent or reflecting material H05B3/845 takes precedence

Abstract

A laminated safety glass window is described having a clear polymer inner layer which includes a pattern of wrinkled resistance wires oriented in non-parallel random fashion so as to reduce glare from the wires when the window is used as a windshield. The individual resistance wires are partially embedded in the polymer sheet by a technique utilizing shrinkage of a thermoplastic polymer from its original dimensions when heated to an elevated temperature together with having the individual wires change configuration when relaxed from tension forces on the wire when first assembled with the polymer sheet. A method of forming the wire-incorporated polymer sheet member is also described along with equipment for automatically applying prestressed resistance wire to a thermoplastic sheet followed by heating the assembly under proper conditions to form the composite member.

Claims

2. A composite sheet member as in claim 1 wherein the layer of thermoplastic polymer undergoes greater shrinkage in a given direction along the major surface compared with a direction along said major surface substantially perpendicular thereto with the path of said resistance wires corresponding to the greater shrinkage direction of the polymer.

3. A composite sheet member which comprises a layer of transparent thermoplastic polymer which has been heat-shrunk from its original dimensions by heating to an elevated temperature having partially embedded in one major surface and extending above said major surface at different elevations where not embedded a plurality of wrinkled resistance wires each connected at opposite ends with common bus-bar electrode means, said individual resistance wires lying in closely spaced relationship and being oriented with respect to one another in non-parallel random fashion governed by thermal expansion differences between the polymer and said resistance wires as well as residual stress in the individual wires with said random orientation of resistance wires appearing both in the plane of said major surface of the polymer layer as well as in a plane at some angle thereto so as to reduce light reflection from the wire.

4. A laminated safety glass member which comprises a pair of glass outer layers having a composite inner layer integrally bonded thereto, said composite inner layer comprising a sheet of transparent thermoplastic polymer which has been heat-shrunk from its original dimensions by heating to an elevated temperature having partially embedded in one major surface a plurality of wrinkled resistance wires which lie in closely spaced relationship and are oriented with respect to one another in non-parallel random fashion so that portions of said individual resistance wires protrude from said major surface of the thermoplastic polymer layer, and bus-bar electrode means connected at each end of the individual resistance wires.

5. A laminated safety glass member as in claim 4 having parallel-connected electrode means to heat the resistance wires.