Abstract:
A lever lock unit includes a housing, a dogging element adapted to actuate a lock bolt, a plurality of lever tumblers that are actuable via the dogging element and movable relative thereto, and a blocking element for blocking movement of the dogging element in the absence of a key or when the wrong key is inserted in the unit. The unit is characterized by a cradle accommodated in the dogging element and adapted to receive the lever tumblers. The dogging element is rotatable and is adapted so that when rotated, the cradle accommodated in the dogging element, and there with also the lever tumblers accomodated in the cradle, will be caused to move linearly in relation to the dogging element and in relation to a key inserted into the unit, for movement of the lever tumblers to a blocking element release position when the correct key is inserted.

Description:
FIELD OF INVENTION 
     The present invention relates to a lever lock unit, and more particularly to a lever lock unit in which movement of the lever tumblers is such as to make forcing and manipulation: of the lock difficult to achieve. 
     The invention also relates to a key for use with such a lock. 
     BACKGROUND ART 
     Known lever locks are constructed so that when turning the lock key, the key seeks for the lever tumblers in order to move the levers to a lock-release position in accordance with a code on the key. This general principle, whereby the key seeks and actuates the lever tumblers as the key is turned is beset with many draw-backs. 
     One of these drawbacks is that turning of the key results in wear between key and lever tumblers, which results in wear marks on both key and lever tumblers in the passage of time. These marks can facilitate manipulation and forcing of the lock. 
     Another drawback is that a multi-key/tumbler system cannot be readily implemented in some lock units of this kind, due to the particular design of the lever tumblers. 
     German Patent Specification 394 690 (Deutsche Türschlieβ-er-Industrie Wilhelm Müller) teaches a lever lock that includes a plate which, when moved, dogs a number of lever tumblers into a lock release position when the correct key is inserted. This relative movement between plate and lever tumblers, and also between plate and key, is a combination of linear movement and rotary movement. This does not avoid the drawback whereby wear marks are formed on the key and lever tumblers. 
     OBJECTS OF THE INVENTION 
     One object of the present invention is to provide a lever lock unit which is more secure than earlier known lock units or assemblies of this kind. 
     Another object is to provide a lever lock unit with Which a key/lever tumbler system,n can be easily included. 
     Another object of the invention is to provide a lock unit which can be constructed from a wide choice of materials. 
     Still another object of the invention is to provide a key that can be used with such a lock unit. 
     DISCLOSURE OF THE INVENTION 
     This object is achieved with a lever lock unit that is accommodated in a housing and includes a dogging element adapted to actuate a lock bolt, a plurality of lever tumblers that are actuable via the dogging element and movable relative thereto, and a blocking element for blocking movement of the dogging element when no key is inserted, or when the wrong key is inserted, wherein the lever lock unit is characterized by a cradle carried in the dogging element and adapted to accommodate the lever tumblers, wherein the dogging element is rotatable and so adapted that rotation of the dogging element will cause the cradle accommodated in the dogging element, and therewith the lever tumblers accommodated in the cradle, to move linearly in relation to the dogging element and in relation to a key inserted in the lock, so as to bring the lever tumblers to a blocking element release position when the correct key has been inserted. 
     The decisive difference between conventional locks in which the key seeks the lever tumblers and lifts the same and the inventive lock construction, is that in the case of the inventive lock construction the lever tumblers, instead, seek the key and stop in the position given by the code. 
     Another difference is that turning of the key causes the cradle to move linearly through the coaction of means provided thereon with corresponding means in one part or the other part of the fixed housing. 
     One of the advantages afforded by the invention is that wear between key and lever tumblers is minimized, thereby avoiding the easily read wear marks that a conventional key will leave on a lever tumbler when striking the same. This greatly increases security of the lock against unauthorized manipulation. 
     Minimization of key wear on the lever tumblers also enables key and tumblers to be made from a wider variety of materials. 
     The invention also relates to a lock according to claim  11  or claim  12 . The key is adapted for use with a lock of the general principle defined in claim  1 . 
     Further preferred embodiments of the invention are set forth in the following dependent claims. 
    
    
     BRIEF DESCRIPTION OF TEE DRAWINGS 
     The invention will now be described in more detail with reference to an exemplifying embodiment thereof and also with reference to the accompanying drawings, in which 
     FIG. 1 is a perspective view of an inventive lock unit; 
     FIG. 2 is a perspective exploded view of the lock unit shown in FIG. 1, and also shows a key for use with the lock; 
     FIGS. 3 a - 3   f  illustrate different stages of a lock locking operation; 
     FIG. 4 illustrates coaction of the lock unit with a lock bolt mounted in a lock chest; 
     FIG. 5 is a perspective exploded view of an alternative embodiment of the lock unit shown in FIG. 1, and shows a key for use with this alternative unit; 
     FIG. 6 is a more detailed view of a groove in the spine of the key shown in FIG. 5; and 
     FIG. 7 illustrates coaction of a lever tumbler with a latch pin in the unit shown in FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Preferred embodiments of the inventive lever lock unit, or latch unit, will now be described in more detail. 
     FIG. 1 shows a lock unit comprising a lock chest having an upper part  10  and a lower part  11 , said parts being screwed together. Both of the chest halves include a key receiving hole  12 . The two chest halves also define an opening  13  through which a lock bolt is able to move. 
     The components of the lock unit  2  are shown in FIG.  2 . Rotatably mounted in the lock chest is a dogging element which in the illustrated embodiment has the form of a drum  20  which is intended to accommodate a cradle  30  between drum walls  22 ,  24  and  26 . The drum walls are designed to permit linear relative movement between drum and cradle. As the drum rotates, the cradle  30  is caused to move linearly in relation to the drum by pins  14 ,  16  that are mounted in the upper chest part  10  and that coact with a curve  36 ,  38  in the form of a cavity or opening  34  in the cradle. 
     The cradle accommodates a plurality of lever tumblers  40 , for instance nine tumblers. These lever tumblers are mutually identical with the exception of the position of code reading grooves or recesses  42  in the side edges of respective tumblers. These recesses or grooves are positioned at mutually different heights corresponding to the pitch of the key code. The tumblers have a width which allows the tumblers to pass between walls  32  of the cradle  30 . Each lever tumbler is provided with two resilient tongues  44 , for abutment with the walls  32 . This provides frictional resistance against relative movement between cradle and lever tumbler. 
     Thus, the cradle and lever tumblers rotate as the drum rotates, while the cradle opening, at the same time, moves relative to the pins  14 ,  16  in the upper chest part. Since the lever tumblers are guided in the cradle in the aforesaid manner, the tumblers will accompany the cradle as it moves until they reach their positions relative to the key, whereupon the resilient tongues  44  hold the tumblers in their adopted positions. 
     A code slide  50  is mounted in the drum  20  for movement at right angles to movement of the cradle in relation to the drum, and forms a code reading part of the lock. The code slide  50  carries a sensing or detecting projection  52  which functions to detect whether or not the correct key has been used in the following manner. As earlier mentioned, the various lever tumblers  40  are displaced to mutually different extents in relation to the drum, and therewith in relation to the code slide  50 , in accordance with the code on the inserted key. When the key code is the correct code, the lever tumblers are moved so that the recesses or grooves  42  in the tumbler side edges form a through-penetrating passageway. The code slide can then be pressed into the passageway formed by said side recesses or grooves  42  by a cam  18  mounted on the upper chest part  10 . This cam  18  also blocks rotation when the wrong key is inserted. The code slide thus corresponds to the latch pin of a typical lever lock. 
     FIG. 2 also shows a key  70  for use with the inventive lock unit. The key includes a key bit  72  which has code surfaces or code grooves  74  cut in one side surface thereof. In the basic embodiment, the other side surface (not shown) of the key lacks code grooves but is machined to a depth that corresponds to the depth of the code grooves. 
     The key bit has a shape and dimensions that coincide with a key-bit receiving recess  46  in respective lever tumblers  40 . The depth of this recess is such as not to impede linear movement of the tumblers in relation to the key as the drum is turned. Instead, this linear movement of the lever tumblers is stopped when the key bit has been inserted into the recess  46  to an extent at which the lever tumblers lie against the code groove  74 . Thus, it is the lever tumblers that move towards the key and that are brought to respective positions in accordance with the key on the key bit. 
     Function 
     A lock locking operation will now be described with reference to FIGS. 3 a - 3   f.    
     FIG. 3 a  shows a starting position in which all lever tumblers are at mutually the same height. This position allows a key to be inserted into the lock. 
     FIG. 3 b  shows the position after the drum  20  has been turned anti-clockwise through about 90°. Rotation of the drum is caused by turning the inserted key, which causes the drum to rotate. 
     Further anti-clockwise rotation causes the cradle, and therewith the lever tumblers, to be moved linearly by the pin  14  in relation to the drum. 
     FIG. 3 c  shows the state of the lock after anti-clockwise rotation through about 130°. In this state of the lock, the cradle has been moved maximally in relation to the drum, which will be evident by the fact that the pin  14  has reached the rounded part of the curved surface  36 . The lever tumblers are in their final positions, or lock release positions, in this stage. The lever tumblers therewith press against the key, when the cradle has moved linearly The lever tumblers are retained in their adopted positions, by the frictional effect of the tongues  44  against the cradle walls  32 . 
     As before mentioned, the code reading recesses form a through-passing passageway for the code slide when the correct key is inserted. The code slide  50  can therewith be pressed-in, i.e. moved in a direction perpendicular to the direction in which the cradle and the lever tumblers have been moved on the other hand, if an incorrect key has been inserted, no through-passing passageway will be formed and the code slide cannot be pressed-in, and rotary movement will be stopped by abutment of the code slide with the cam  18 . 
     FIG. 3 d  shows the code reading projection or talon  52  on the code slide  50  pressed into the passageway formed by the recesses  42 . Turning of the key, and therewith the drum, can therefore be continued. 
     FIG. 3 e  illustrates the lock components when an angle of 130° remains of the anti-clockwise rotary movement. The code slide  50  has been caused to leave the passageway formed by the lever tumblers by a second cam  19  (FIG. 2) on the lower chest part, and the fixed pins  14 ,  16  in the upper chest half have moved out of engagement with the first curve  36  in the cradle. 
     FIG. 3 f  shows that continued rotation brings the second curved surface  38  in the cradle opening  34  and the first pin  14  into contact with one another, whereby the cradle and, thereby, the lever tumblers are returned to the starting position shown in FIG. 3 a.    
     In the aforedescribed rotation of the drum, a bolt actuator  28  actuates a lock construction so as to lock the lock, see the following description of FIG.  4 . 
     The aforedescribed sequence of events is reversed when rotating the drum in the opposite direction, i.e. clockwise in FIGS. 3 a - 3   f.  One difference is that the second pin  16  is the first pin to engage the curved surfaces  36 ,  38  in the cradle opening, and not the first pin  14 . 
     FIG. 4 shows the coaction of a lock unit  2  housed in a lock chest  80  with a locking bolt or latch bolt  82 , via a link arm  84 . When the drum  20  is caused to rotate clockwise, by turning the key  70  clockwise in the lock, the bolt actuator  28  will engage in a recess  86  on the link arm  84  after the drum has been turned through about 170°. Further clockwise rotation of the key urges the link arm to the left in the Figure, wherewith the bolt  82  mounted on pivot  88  is caused to rotate clockwise into the lock chest, therewith unlocking the door. When locking the door, the movements are the reverse to those described, i.e. the key is turned anti-clockwise and the lock bolt is rotated clockwise out from the lock chest. 
     Description of an Embodiment that Includes a Latch Pin 
     The lock of the aforedescribed embodiment has a given level of security, i.e. the code grooves on the key bit determine whether or not the drum can be rotated. With the intention of providing greater security, there is proposed a further preferred embodiment in which the lock unit also includes latch pins that are intended to block movement of the lever tumblers  40  when a wrong key is inserted into the lock. 
     FIG. 5, which corresponds to FIG. 2 illustrating the first embodiment, shows the further embodiment that includes latch pins, wherein those components of the FIG. 2 embodiment that find correspondence in the FIG. 5 embodiment have been identified by the same reference numerals to which a prime has been added. 
     It will be evident from FIG. 5 that a plurality of latch pins  60  are linearly mounted in the drum  20 ′ for linear movement transversely to the direction of movement of the lever tumblers  40 ′. The lever tumblers include a recess or notch  48  in the side surfaces of an opening in the lever tumblers, see FIG.  7 . These notches  48  are disposed at a height or level which enables a latch pin  60  to engage in a respective notch when the lever tumblers  40 ′ are located in their respective start positions. 
     Movement of the latch pins  60  is guided forcibly by a groove  76  provided on the spine of the key  70 ′ and the shape of which will be seen more clearly from FIG.  6 . Insertion of the key into the lock unit guides a circumferentially extending flange  62  on the latch pin to a position on a level with the pin concerned, this position being determined by the groove  76  in the key spine. If the key does not have the correct spine code, i.e. the correct groove shape, at least one of the latch pins  60  will be brought to a position in which a latching end  64  of said pin engages a corresponding notch  48  in a lever tumbler  40 ′, thereby blocking linearly movement of the lever tumbler in relation to the drum. 
     Description of Further Embodiments 
     As will be evident from the drawings, the general shape of the lever tumblers is generally symmetrical in an axial direction, with the exception of the recess  42 . In the preferred embodiment, the recesses  42  are disposed at different heights in both left and right side edges, as evident from FIG.  2 . This provides a lever tumbler which can be used for two different coding positions, simply by turning the tumblers about face. This is beneficial, because it reduces the number of different lever tumblers required and therewith the number that must be kept in stock. For instance, four different types of lever tumbler will suffice for seven different coding positions. 
     Furthermore, several code-slide receiving recesses  42  can be provided on one and the same side surface. Such lever tumblers may be used in locks having mutually different key levels. This enables the provision of lock systems, i.e. a system in which several different key codes fit one and the same lock. 
     The lever tumblers  40 ,  40 ′ of the described lock unit are preferably made of brass, although they may alternatively be made of some reinforced plastic material. 
     The illustrated key  70 ,  70 ′ has grooves cut in only one side surface of the key bit  72 . However, corresponding grooves may also be cut on the other side of the key bit, said codes on respective sides being either symmetrical or asymmetrical. This provides greater security, since more key combinations are therewith made possible. 
     In all of the illustrated embodiments, the drum, the cradle, and the lever tumblers are rotated by turning a key inserted into the lock. However, other turning means are conceivable. For instance, the drum may be connected to an electric motor or to a handle or knob, such as in the case of a vault or safe, for instance. The key need not therewith be provided with a typical key grip or the like. The key is also subjected to less force, which enables it to be made of a weaker material, such as a plastic material. 
     It will be understood that the lock unit need not necessarily be placed in a lock chest, as illustrated in the FIG. 4 example. Instead, the lock unit may be mounted on the outside of a door, in which case the unit will have a cylindrical configuration.