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US 4,285,221 AGranted
Retrofit doorknob lock apparatus
OwnerMaxwell G. Atchissoninventor
Life of this patent
Estimating the term…
Abstract
Apparatus for securing a doorknob against unauthorized entry. A shroud fits over the entire doorknob and its associated shaft, and extends to fit on or over the rose through which the shaft extends. A clevis fits through slots in the shroud to retain the shroud in place on the door knob and shaft. The present apparatus can be used to retrofit a lock onto an existing knob which has no locking structure, and also prevents tampering or unauthorized access to an existing built-in lock cylinder of a doorknob.
Claims4
Retrofit lock apparatus for a door knob, comprising:
- means operative to fit over and entirely enclose a knob and associated shaft of a doorknob, so as to shroud the knob and shaft from unauthorized access;
- and
- means selectably operative to retain said enclosing means in place shrouding the knob and shaft;
- said enclosing means comprising an enclosure having an open end to receive the knob and to permit said enclosure to fit over the knob and associated shaft;
- said enclosure having a plurality of openings located at different spacings from said open end;
- and
- said retaining means extending within a selected one of said openings to maintain said enclosure in place shrouding the knob and shaft.
4 more elements
Dependencies are inferred from the claim text.