Sheets of stretched and polarized polymer materials and method of manufacturer
Patent 5024872 Issued on June 18, 1991. Estimated Expiration Date: 
June 18, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 18, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2399820 3921125 Electret cable hydrophone array Combined electret hydrophone and transmission line System for pulse data transmission through water-return cables Pressure compensating coaxial line hydrophone and method Underwater acoustic reflectors Elongated seismic receiver of continuous structure Piezo-electric film manufacture Acoustically transparent hydrophone probe InventorsAssigneeApplicationNo. 086176 filed on 08/13/1987US Classes:428/212, Including components having same physical characteristic in differing degree428/421Of fluorinated addition polymer from unsaturated monomersExaminersPrimary: Herbert, Thomas J. Jr.Attorney, Agent or FirmForeign Patent References
International ClassesB32B 007/02B32B 027/00 AbstractA sheet of polymer material is secured between a pair of clamping members. The sheet is directed through a localized heated region to provide a localized heated portion of said sheet. A first one of said clamping members is pulled away from the second clamping members to stretch said sheet and create from the localized heated portion of said sheet a neck-down region. The neck-down region separates providing a pair of neck-down region portions and a reduced thickness portion or stretched portion of the sheet between said neck-down region portions. One of said neck-down regions propagates along unstretched portions of the sheet as the movable clamping member moves away from the fixed clamping member while the other neck-down region remains adjacent the fixed member. This propagating neck-down region portion of the sheet is kept within the localized heated region by moving the localized heated region at a rate related to the rate which unstretched material of the sheet is fed into the neck-down region portion. While the neck-down region portion is maintained within the localized heated region, an electric field is applied to the neck-down region portion to polarize the film.Other References
Field of SearchOf fluorinated addition polymer from unsaturated monomersAddition polymer is perhalogenated Including components having same physical characteristic in differing degree Free metal or mineral containing Elongated continuous type Elongated cylindrical element With reflector SIGNAL TRANSDUCERS With diaphragm Piezoelectric elements and devices Cable or capacity | |
