Title:
TAMPER-RESISTANT FASTENER AND METHOD AND TOOL FOR USE WITH SAME
Document Type and Number:
WIPO Patent Application WO2005042985
Kind Code:
A3
Abstract:
A fastener includes a round, blind hole or pocket in its head. Installation and removal of the fastener is accomplished with a tool containing an eccentric segment on the end of a shaft. When rotated within the pocket, the eccentric segment displaces laterally relative to the shaft to provide a friction grip to the lateral wall of the pocket. The strength of the grip is proportional to the applied torque. Eccentric displacement allows rotation but prevents the tool from spinning out of the fastener thereby eliminating cam-out and surface damage resulting from contact with a spinning tool tip. The eccentric head of the tool can be made disposable and to shear off when a predetermined torque is reached. The smooth-sided round hole offers no purchase for commonly available tools; making the fastener tamper-resistance. In another embodiment, the fastener includes a raised portion in the pocket. A tool having a complementary opening shears off the raised portion at a predetermined torque.
Inventors:
FLESHER ROBERT W (US)
Application Number:
PCT/US2004/035141
Publication Date:
November 24, 2005
Filing Date:
October 22, 2004
Export Citation:
Assignee:
FLESHER ROBERT W (US)
International Classes:
B25B13/48; B25B15/00; B25B23/00; F16B23/00; F16B31/02; F16B35/06; F16B41/00; F16B; (IPC1-7): F16B23/00; F16B35/06; B25B13/48; B25B15/00; B25B23/00
Domestic Patent References:
| WO1989009886A1 | 1989-10-19 |
Foreign References:
| US1298398A | 1919-03-25 | |||
| US3369441A | 1968-02-20 | |||
| US4258596A | 1981-03-31 |
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