Locks – Operating mechanism – Key
Patent
1997-05-29
1998-03-10
Gall, Lloyd A.
Locks
Operating mechanism
Key
70395, 70399, 70409, E05B 1908, E05B 2704
Patent
active
057248419
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to a key and cylinder lock unit.
DESCRIPTION OF THE PRIOR ART
Locks are known comprising a plug housed in a cylinder and provided with a plurality of radial pins formed in two parts movable along corresponding radial channels provided partly in the plug and partly in the cylinder. For a particular axial position of the various pins the surface of separation between the two parts thereof coincides with the surface of discontinuity between the plug and cylinder to allow this to be freely rotated by a key which, when inserted into the plug, determines that particular axial position of said pins by virtue of its pattern.
The level of lock security is related to the difficulty of forming a blank key, the number of possible patterns, and the difficult of duplicating a key using a blank, ie of cutting an uncut key.
To increase this level of lock security it has already been proposed to provide the key with a member which is movable relative to the remainder of the shank between a position in which it is totally contained within the overall contour of the key and a position in which it projects from this overall contour. The function of this movable member is to cooperate with a projection at the end of the seat provided in the plug to receive the key, and in this manner to cause the movable member to assume its projecting position, in which it can activate a further two-part pin housed partly in the plug and partly in the cylinder.
However even with this expedient, unauthorized operation of the lock is possible by a wrongdoer who, provided with an appropriate implement, can insert it into the seat provided in the plug for the key, in order to operate the various pins one at a time and cause them to assume that position which enables the plug to be rotated.
EP-A-0 354 838 discloses a safety cylinder of the type comprising at least one rotor mounted rotatably in a stator and possessing parallel to its axis a conduit suitable for the insertion of a key. For interaction with a key, of which the end of the active part forms as a whole an oscillating end piece, the conduit of the rotor possesses, at a distance from its entrance, a widened portion capable of allowing a tilting of the oscillating end piece of the key, with at least one piston entering this widened portion and governed by the entire combination to be adhered to and deflection means capable of directing this oscillating end piece onto this piston.
SUMMARY OF THE INVENTION
The main object of the invention is to provide a key and cylinder lock unit in which it is impossible to gain access to the key seat in the plug using implements other than the key itself.
A further object of the invention is to provide a key which is difficult to reproduce.
These and further aims are attained according to the invention through a key and cylinder lock unit, in which the key comprises a shank provided with a pattern and with at least one movable member positioned at the front end thereof, the lock comprising a plug housed within a cylinder and provided with a plurality of substantially radial pins formed in two parts movable along corresponding radial channels provided partly in the plug and partly in the cylinder and, by means of springs, maintained with one end in the longitudinal seat provided in said plug for the insertion of the shank of said key, characterised in that: introduction end and housing the tapered end of all the pins, which completely traverse said seat; deviated towards said longitudinal groove as a result of the progressive introduction of the shank into said seat, and to engage the end of the successively encountered pins in order to shift them axially until they are able to slide along that surface of said shank comprising said pattern .
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention and a modification thereof are described in detail hereinafter with reference to the accompanying drawings, in which:
FIG. 1 is a perspective view of a key forming part of the unit
REFERENCES:
patent: 1567979 (1925-12-01), Northrop
patent: 1735868 (1929-11-01), Klingel
patent: 2032974 (1936-03-01), Bradshaw
patent: 3974670 (1976-08-01), Wolter
patent: 4683740 (1987-08-01), Errani
patent: 5170651 (1992-12-01), Errani
Gall Lloyd A.
Silca S.p.A.
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