发明名称 Doorknob guard
摘要 A device which protects the knob of a door lock to prevent the breaking thereof and entry includes an outer cylindrical member rotatably secured about the knob assembly by the rose of the knob assembly. An inner cylindrical member is secured about the knob assembly, and includes a plurality of axially extending grooves which engage cooperating ribs extending inwardly from the outer member. The inner member includes a hole in one end thereof to permit key access to the knob, and at least one annular friction ring disposed within the inner member for transmitting a limited magnitude of torque to the knob. The device protects the knob assembly by preventing tampering therewith and also preventing breaking the lock by applying high torque to the knob.
申请公布号 US4007956(A) 申请公布日期 1977.02.15
申请号 US19750580294 申请日期 1975.05.23
申请人 HARRIS, STEVEN K.;SCHIFFMAN, STANLEY P. 发明人 HARRIS, STEVEN K.;SCHIFFMAN, STANLEY P.
分类号 E05B13/00;(IPC1-7):E05C19/18 主分类号 E05B13/00
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