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1. (WO2017033183) WASHERS FOR OVER-TIGHTENING PREVENTION OR MITIGATION

Pub. No.:    WO/2017/033183    International Application No.:    PCT/IL2016/050913
Publication Date: Fri Mar 03 00:59:59 CET 2017 International Filing Date: Mon Aug 22 01:59:59 CEST 2016
IPC: F16B 39/284
F16B 39/24
F16B 39/10
Applicants: BOGRASH, Philip
Inventors: BOGRASH, Philip
Title: WASHERS FOR OVER-TIGHTENING PREVENTION OR MITIGATION
Abstract:
A lock-washer of conical, annular or other shapes capable of elastic flattening when the threaded connection, of which it is a part, is tightened and having tabs along the perimeter of the central hole. For most embodiments the tabs' tips form a circle of a diameter slightly larger than that of a threaded part which is to pass through the central hole. When during tightening the axial force acting on the lock-washer reaches a pre- determined level and the lock-washer flattens, its central hole diameter decreases and the tab tips enter the thread channel, which will cause the thread to jam, thus preventing further tightening, thereby limiting the axial load in the threaded connection to a pre-determined level. Another embodiment provides a lock-washer which compresses and expands radially during tightening providing a visual and/or audible signal for the worker when said expansion and a corresponding axial load reach the designated level.