US3771340A

US3771340A - Lock system

Info

Publication number: US3771340A
Application number: US00135171A
Authority: US
Inventors: P Krakstrom
Original assignee: Wartsila Oy AB
Current assignee: Wartsila Oy AB
Priority date: 1971-04-19
Filing date: 1971-04-19
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13

Abstract

A lock arrangement comprising a cylinder lock with turnable locking disks and a number of different keys. One or several of the keys are normal keys for normal operation of the lock, but there are also a first special key by means of which a locking of the normal function of the lock can be obtained, and a second special key which is used to release this locking. The first special key is provided with means for turning a number of the locking disks into one turning direction and for bringing a smaller number of the locking disks back into their initial position, thereby leaving the return of at least one locking disk incomplete. The incompletely returned locking disk forms an obstacle in the keyway of the lock and prevents proper insertion of the normal key.

Description

[ Nov. 13, 1973 LOCK SYSTEM Primary Examiner-Albert G. Craig Jr. Inventor: Paul Kriikstriim, Helsinki, Finland Attmey waters Rodm Schwartz & Nlssen Assignee: 0y Wartslla Ab, Helsinki, Finland ABSTRACT 1971 i A lock arrangement comprising a cylinder lock with Appl. No.: 135,171 turnable locking disks and a number of different keys. One or several of the keys are normal keys for normal 70/338, 7O/366, 7O/407 operation of the lock, but there are also a first special 70/4O9 key by means of whlch a locking of the normal func- Int. EOSb /02, EOSb /08 can be Obtametd' a specal key WlllCh is used to release this locking. The first spe- Fleld of Search...................... /338, 339, 366, 1k d f b 70/4O7 409 cm ey 1S provr e Wlt means or turning a num er of the locking disks mto one turning direction and for bringing a smaller number of the locking disks back References Cited Into their initial position, thereby leaving the return of UNITED STATES PATENTS at least one locking disk incomplete. The incompletely Unite States atent Krikstriim [22] Filed:

8 Claims, 4 Drawing Figures returned locking disk forms an obstacle in the keyway of the lock and prevents proper insertion of the normal key.

m m m Koskinen et um am. co ab BFC 500 1917 9899 llll l 4l 0279 6 78 1431 6252 ll 3 LOCK SYSTEM The invention relates to a lock and key system to which belongs a cylinder lock comprising a stationary cylinder housing enclosing a rotatable lock cylinder in which there are a plurality of locking disks turnable by means of the key of the lock, which disks by turning of the key in one direction are brought into a cylinder releasing position and by reverse turning of the key are by a return surface on the key brought back to their initial position.

In the Finnish patent application No. 1640/69, which is still pending, a lock is disclosed which can be temporarily locked so that it cannot be opened with its normal key. However, this lock has the drawback that it has to be provided with a special locking disk, whereby the lock becomes more expensive than a standard lock. The use of the lock is also relatively complicated.

The object of the invention is to provide a cylinder lock with turnable locking disks which can be temporarily locked so that the normal key of the lock does not work, but which at the same time is as simple as possible and deviates from a standard lock as little as possible. The invention is characterized in that the lock system comprises a special key with a return surface provided with such a recess that the return movement of preferably one of the innermost locking disks of the lock remains incomplete. Due to this incomplete return, the normal key cannot be pushed into its proper position, i.e., to the bottom of the lock, and hence, the use of the normal key is prevented. In order to obtain this kind of locking, a special key is needed, and in order to remove the locking another special key is needed. However, the lock itself does not have to be changed in any way, it is still a normal standard lock.

In a preferred embodiment of the invention, there is in front of the locking disk which is to be incompletely returned a so called fixed locking disk, the turning of which relative to the lock cylinder is prevented. If this fixed locking disk would not be situated'in front of the incompletely returned locking disk, it would be possible to turn back the incompletely returned locking disk to its initial position with a normal key even if this operation would be relatively complicated to perform. The fixed locking disk gives the advantage that the releasing ofthe locking is quite impossible to perform with a normal key.

The recess in the return surface of the special key usually has the form of a circular sector. The extent of the sector removed determines the degree of incom sition of the fixed locking disk, but this makes the key very weak. As the key in question is a special key, the object of which merely is to provide a locking of the lock, the strength of the key can be improved by making the cut at the position of the fixed locking disk smaller than a right angle.

To release the locking of the lock a second special key is needed being provided at its end on the side of the return surface with a helical or oblique surface by means of which the incomplete return of the locking disk can be made complete by pushing the key in an axial direction into the lock. In order to secure that this reset key functions in the intended way, said helical or oblique surface is preferably arranged so that it extends through a key sector which is somewhat larger than the angle corresponding to the incomplete return of the locking disk. Said helical or oblique surface can also be made in a normal key of the lock or in any other special key which may belong to the locking system. The making of the helical or oblique surface will in general be somewhat easier if there is a groove or a groove-like recess at the position of theturning' axis of the key in question.

In the following, the invention will be more fully described with reference to the attached drawing in which FIG. 1 shows an axial section through a lock according to the invention, 7

FIG. 2 shows a cross-section of a key belonging to this lock,

FIG. 3 shows a special key needed to obtain locking of the normal function of the lock, and

FIG. 4 shows a special key needed to release said locking.

In the drawing, 10 indicates the stationary cylinder housing of a cylinder lock, 11 a lock cylinder rotatable in the cylinder housing, 12 locking disks, and 13 a so called fixed locking disk. The lock is operated by keys having a basicly semicylindrical blade portion. FIG. 2 shows schematically a cross-section of this kind of a key.

From the one half of the key, sectors of different extent are removed by means of milling, and the extent of the sector removed determines how much the key is able to turn the locking disks 12 of the lock. The different cuts are in FIG. 2 indicated by

numerals

0,1,2,3,4, and 5, whereby 5 indicates the greatest cut and 0 the smallest, i.e., that nothing has been cut from the key. A zero cut turns the locking disk through the greatest angle and a five-cut does not turn the locking disk at all. Consequently, there has to be a five-cut in the key at the position of the fixed locking disk 13. The other half of the key, that is thesurface 14, works as a return surface and returns the locking disks 12 to their initial position during the return movement of the key.

In the return surface 14 of the special key shown in FIG. 3, there is at the end of the key a recess 15 having the form of a three-cut of a normal key. If the lock is provided with a fixed locking disk 13, the key has to be provided with a cut in the opposite side of the key at the position of this locking disk. This cut does not have to be a five-cut, because, the locking of the normal function of the lock does not require as great a turning of the key as the normal use of the lock. Consequently, the cut 16 at the position of the fixed locking disk can also be a three-cut. By this means the advantage is obtained that the portion of the key where the

cuts

15 and 16 meet will not be too weak.

In FIG. 4, a second special key is shown the object of which is to release the locking obtained by use of the key shown in FIG. 3. At the end of the return surface 14 of this second special key, there is a helical or oblique surface 17 covering a key sector, which seen in an axial direction of the key is somewhat larger than the cut 15, so that the desired returning of the locking disk with certainty will be obtained when the key is axially pushed into the lock. The making of the helical or oblique surface 17 is somewhat easier if a groove-like recess 18 is made in the plane surface of the key.

I claim:

1. A lock arrangement comprising a cylinder lock and a number of different keys, said cylinder lock comprising a stationary cylinder housing and a cylinder rotatable therein, said cylinder enclosing a plurality of locking disks turnable by at least one of said keys when inserted into said lock, said last mentioned key being a normal key used for normal operation of said lock, another of said keys being a first special key provided with means for turning a number of said locking disks into one turning direction and for bringing a smaller number of said locking disks back into their initial position, thus leaving the return of at least one locking disk incomplete so as to form an obstacle in the keyway of the lock preventing proper insertion of said normal key.

2. An arrangement according to claim 1, in which said means for leaving the return of one locking disk incomplete consists of a recess made in one side of said first special key.

3. An arrangement according to claim 1, in which said lock is provided with a locking disk being fixed against turning relative to said cylinder and situated in front of said locking disk which is to be incompletely returned.

4. An arrangement according to claim 2, in which,

said recess is included in a sector having its apex on the turning axis of said first special key and an apex angle of at the most 60.

5. An arrangement according to claim 3, in which said first special key is provided at a position corresponding to the position of said fixed locking disk with a cut included in a sector having its apex on the turning axis of said first special key and having an apex angle of considerably less than 6. An arrangement according to claim 1, comprising a second special key having at its end on one side of a generally oblique surface engaging said incompletely returned locking disk when said second special key is axially pushed into said lock.

7. An arrangement according to claim 6, in which said generally oblique surface extends through a sector having its apex on the turning axis of said second special key and being somewhat larger than the angle of incompleteness of the incompletely returned locking disk.

8. An arrangement according to claim 6, in which said second special key is at its end, adjacent toysaid generally oblique surface provided with a central groove.

Claims

4. An arrangement according to claim 2, in which said recess is included in a sector having its apex on the turning axis of said first special key and an apex angle of at the most 60*.

5. An arrangement according to claim 3, in which said first special key is provided at a position corresponding to the position of said fixed locking disk with a cut included in a sector having its apex on the turning axis of said first special key and having an apex angle of considerably less than 90*.

6. An arrangement according to claim 1, comprising a second special key having at its end on one side of a generally oblique surface engaging said incompletely returned locking disk when said second special key is axially pushed into said lock.

8. An arrangement according to claim 6, in which said second special key is at its end, adjacent to said generally oblique surface provided with a central groove.