Key-operated device for access control system
AssigneeUnimax Switch Limited
InventorJohn C. Corfield
Life of this patent
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Abstract
A key-operated device, for example for controlling access to switch gear or potentially dangerous machinery, has a rotary motion with an axially inserted key but departs from the usual barrel lock construction which is sensitive to foreign matter. Instead it has a faceplate in front of a stationary body with a cylindrical member rotatable in it and having a recess for the key and circumferentially spaced notches in a flange close behind the plate and prevented from direct access through the keyhole by a fixed axially extending wall on the back of the plate but accessible by appropriate lugs on the key when the latter is inserted. The rotatable member is connected through a spindle to a switch, valve or latch or other actuated device.
Claims7
A key-operated device comprising a fixed hollow body having a plate-like wall, said wall having therein a key-hole for the admission of an end of a key inserted on an axis traversing said wall and passing through said key-hole, an actuating member mounted within said body to be rotatable about said axis, said member having therein a recess open towards said key-hole and having at that end thereof which is adjacent said plate-like wall an annular flange directed inwardly towards said axis, said flange having an innermost edge and having at least one notch formation capable of being engaged to transmit torque to said flange to rotate said member, a basically cylindrical wall provided on said body around said key-hole and extending axially inwardly from said plate-like wall to overlie said innermost edge of said flange on said member, a key comprising a stem lying on an axis and at least one lug projecting laterally from said stem and including a portion extending parallel to but offset from the axis of said stem, said stem being adapted to enter said key-hole, and said plate-like wall and axially extending wall being shaped to provide clearance for said lug, whereby on insertion of said key into said key-hole said axially extending portion of said lug can be caused to enter said body and said recess in said member and to engage said notch in said flange in a position radially outwards of said axially extending wall to transmit torque to said flange in order to rotate said member about said axis.
Dependencies are inferred from the claim text.