Locks – Special application – For closures
Patent
1980-06-18
1982-07-13
Wolfe, Robert L.
Locks
Special application
For closures
70207, 70352, E05B 2100, E05B 2500
Patent
active
043388051
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a lock of the kind stated in the preamble of claim 1, i.e. a lock which is operable by means of a punched card serving as a key.
In a lock of this kind known from the Swedish patent specification No. 365 572, the blocking means are formed as pins and are actuated by control pins with pointed ends, which fit into corresponding recesses or blind holes in the key card.
To enable a large amount of combinations the key card must have a certain thickness, so that the blind holes can be made of different depths and, moreover, a bevel serving as a cam is needed to lift the control pins when the card is inserted. Therefore, the latter must be made of a hard and wear-resistant material, such as steel, and be produced with great precision.
The object of the invention is to achieve a lock of the above kind, such that the wear of the key card is reduced to a minimum when the same is inserted into the lock. Furthermore, the card should be made as thin as possible and, in spite thereof, it should permit a large number of locking combinations and preferably be made of plastic material.
As appears from claim 1, the lock according to the invention has the features that each blocking means comprises a substantially arcuate portion, whereas the card of the lock has through-going slits located and dimensioned to receive the arcuate portions of the blocking means. It is hereby achieved that upon inserting the punched card, the arcuate portions of the spring-loaded blocking means can easily slide or roll up onto the card, i.e. with negligible friction, and thereafter be pressed down by their springs into the corresponding, through-going slits of the card, so that all of the blocking means are brought into releasing positions. Of course, the blocking means should be mounted in such a way that they block even during the insertion of the card and, likewise, if a similar, but false key card or another object is inserted into the lock.
In a preferred embodiment, the blocking means are circular, in particular annular, and are guided by slits in mutually parallel plates being connected at some distance to each other and forming together a locking mechanism which is displaceable in a lock casing. When inserting the punched card transversally to the displacement direction of the locking mechanism and in parallel to the plane of the circular, annular blocking means, these blocking means will roll up onto the card and be resiliently pressed down into the slits of the punched card, whereby the blocking means take well-defined positions being free from locking tongues in the upper and lower parts of the lock casing. The springs of the blocking means, especially helical springs, are preferably guided within sleeves, which are arranged inside each circular ring and have recesses in their upper and lower parts so as to permit the rings to perform a rather large motion upwards and downwards.
The invention will be described further below the reference to the drawings, which illustrate a preferred embodiment of the lock according to the invention.
FIG. 1 is a perspective view of a lock according to the invention and a corresponding punched card key;
FIG. 2 is a side view of the lock, partly in axial section;
FIG. 3 is an exploded view of the different portions of a locking mechanism; and
FIGS. 4a-c are cross-sectional views of the lock in a "lower locking position", an "upper locking position", and a "central releasing position", respectively.
FIG. 1 illustrates the box-shaped casing 1 of the lock which is suitably made of metal sheet and comprises locking tongues, 1a,1b punched into the upper and lower parts thereof, said locking tongues co-operating with an internal locking mechanism 2. The latter is connected to a bolt 2a protruding through an opening in the front end 1c of the lock casing and to a lock grip 2b protruding transversally from one side of the lock casing, said grip having an insertion opening 2c for receiving a punched card 3 serving as a key.
As appears from FIG. 2, the locking mechanism 2 is linearly dis
REFERENCES:
patent: 853926 (1907-05-01), Hope
patent: 3780548 (1973-12-01), Anastasov
patent: 4007615 (1977-02-01), Nossum
patent: 4149394 (1979-04-01), Sornes
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