Locks – Operating mechanism – Key
Reexamination Certificate
2000-02-04
2001-11-13
Camby, Richard M. (Department: 3661)
Locks
Operating mechanism
Key
C070S357000, C070S493000
Reexamination Certificate
active
06314774
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a cylinder lock of the kind defined in the preamble of claim
1
.
Cylinder locks of this kind enable a person that possesses a service key, e.g. the janitor of a block of rented apartments, or flats, is able to enter an apartment, but only when the owner of the apartment so permits. In this case, when the owner leaves the apartment he or she will turn the cylinder plug to the service mode and therewith enable the janitor to enter the apartment by means of a service key.
However, when the janitor leaves the apartment, he/she is unable to turn the lock cylinder to its standard mode, since the service key cannot be removed from the lock with the lock in the service mode.
A person having access to a service key is unable to enter an apartment where the lock cylinder has been left in the standard mode of the lock by the owner of the apartment as he/she leaves. Although the janitor can, as a rule, insert the key in the key slot, rotation of the cylinder plug is prevented by one or more pins located in the pin channels. However, the cylinder plug can be turned with the aid of the standard key, regardless of whether the lock is in its standard or its service mode.
DESCRIPTION OF THE BACKGROUND ART
SE,B,8307139-9 (GKN-Stenman) describes a lock of this kind in which one of the intermediate pins has a larger diameter than corresponding upper pins in the first row of pin channels, and corresponding pin channels in the cylinder plug have a flared or widened part that is able to receive an intermediate pin of larger diameter. The intermediate pin can therewith be received in the widened part of said pin channel in the cylinder plug, but is unable to enter pin channels in the cylinder housing of smaller diameter, therewith latching the service key. Although this solution is simple from a technical aspect of lock manufacture, there is a danger that the intermediate pin will wedge firmly between a widened and a narrower channel part if an attempt is made to remove the service key when the lock is in its standard mode, therewith making it impossible to return the cylinder plug to the service mode. This, in turn, totally prevents removal of the service key, whereupon it becomes necessary to break open the lock in order to open the door.
NO,A,8007660-1 (Elkem-Spigerverket) describes another arrangement in which the number of pin channels in the standard mode differs from the number of pin channels in the service mode. Withdrawal of the service key in the normal mode is prevented by virtue of corresponding lower pins being unable to move upwards in this mode. However, it is relatively easy to grind down a relevant part of the key such as to avoid the latching effect.
SE,B,8800818-0 (Publication No. 460 797) (ASSA) describes a lock according to the preamble of claim
1
, in other words the lock also includes a separate latching element that assists in preventing withdrawal of the service key in the standard mode of the lock. The latching element described in this document is disposed in the region between the inner end of the cylinder plug and the drive element, and will be subjected to comparatively large stresses and strains with subsequent wear in conjunction with use, and particularly in view of the necessary slenderness of the latching element. This presents the danger of a malfunction, therewith jeopardising the reliability of the lock system as a whole. For instance, when the plug is insufficiently displaced axially there is a greater risk that one or more pins will pass unintentionally into the pin channels in the plug and therewith prevent its rotation.
OBJECTS OF THE INVENTION
An object of the present invention is to avoid the drawbacks of known cylinder locks of this particular kind.
Another object of the invention is to provide a latching element which is essentially free from stresses and strains and therewith subjected to much less wear and tear, particularly in conjunction with the use of the standard key, which is, after all, used more frequently than the service key.
Still another object of the present invention is to provide a cylinder lock where the plug can be moved axially but where such movement is avoided when using a standard key.
SUMMARY OF THE INVENTION
These and other objects of the invention are fulfilled by an inventive cylinder lock of the kind defined in the introduction and having the characteristic features set forth in the characterising clause of claim
1
.
Because the latching element can be rotated together with the plug, and can also be fixed relative to the plug in the aforesaid manner, the latching element will not be subjected to heavy strain when carrying out its intended function as the lock is turned by means of the service key. The latching element can also be given a comparatively robust and reliable construction and need not therefore be subjected to any form of wear that will jeopardise its function, even after a long time in use.
This essentially eliminates the risk of the plug not being displaced during passage of the standard mode under the action of the service key, which could result in unintentional blocking of the pin channels in the plug and destruction of the entire locking function.
It is preferred in practice that the latching element will be held fixed when withdrawing the standard key in the service mode and that said element is kept fixed after inserting the service key and turning the plug by means of this key.
The plug can thus be rotated readily from the service mode by means of the service key while the latching element is held in its fixed position. Axial displacement of the plug in conjunction with the passage of the standard mode therewith takes place with the latching element in said fixed position. When the plug is turned by means of the standard key, the latching element will, instead, accompany this movement and the plug will not therefore move axially.
The latching element is preferably held fixed by a pin, suitably an intermediate pin, that has a part that enters into the second row of pin channels. Thus, when the service key is inserted into the lock with the lock in its service mode, the parting line will lie between the plug and the latching element. On the other hand, when a standard key is inserted into a lock with the lock in its service mode, a parting line will lie between the outside of the latching element and the surrounding housing, i.e. the latching element can be rotated together with the plug by means of a pin, suitably an intermediate pin, hose one end enters the pin channel in the plug.
According to the invention, the latching element is also adapted to co-act with the driver so as to enable the plug and the driver to move axially as the plug is rotated by the service key and then passes the standard mode.
According to one embodiment preferred in practice, the latching element is preferably a generally cylindrical element which surrounds the inner end of the plug either completely or partially and which includes a radially extending hole that functions as a pin channel, so as to allow a pin in a corresponding pin channel in the housing and the core, respectively, to move in a radial direction.
The latching element may be provided at its inner end with a flange collar and/or one or more axially facing devices, for instance a recess or notches, for co-action with corresponding axially extending driver-mounted devices, for instance projections or nips, such that the plug and the driver can move axially relative to the latching element in a certain position of rotation of said plug and said driver and are returned to their initial position in another position of rotation.
The plug and the latching element may also include mutually co-acting devices, such as pins or beads, which cause the plug to move axially in conjunction with its passage of the standard mode when rotated by the service key.
Further characteristic features of the invention and advantages afforded thereby will be apparent from the following description of a preferred embodiment given with refe
Assa AB
Camby Richard M.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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