Master-slave Key

Abstract

A locking assembly comprising at least two key plugs each having a keyway each of which is positioned in communicating relation with a set of either slave or master tumblers. The plurality of tumblers in each set movably engage the correspondingly positioned plurality of tumblers in the outer set such that the locking-unlocking combination may be varied by inserting keys having different bitings in the keyway associated with the master tumblers thereby automatically positioning the master tumblers such that unlocking the assembly can only be accomplished by positioning the slave tumblers in predetermined positions through the use of a second key having the same biting or a predetermined biting relative to the first key. Key removal prevention means may also be mounted on the assembly such that removal of either key is prevented unless the keys are in locked or unlocked position. Securing means may be also provided wherein the position of the slave and master tumblers are initially set by a first key whereupon the securing means is arranged in securing position so as to maintain the master tumbler in a predetermined, set position relative to the slave tumbler thereby allowing for variable determining of the locking-unlocking combination by only a single key.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

A locking assembly comprising a plurality of slave tumblers movably engaging a plurality of master tumblers whereby the unlocking-locking mode of the assembly is determined by the relative, predetermined position of both sets of tumblers which in turn are determined by the biting of one or more keys movably engaging said tumbler sets so that the assembly will automatically adjust itself to an unlimited number of key combinations.

2. Description of the Prior Art

Various locking devices and in particular locks involving the use of keys have been known for many years in the prior art. A number of these conventional type locking devices are of the type which utilize one or more movable tumblers. Generally speaking, the position of the tumblers relative to the other structural elements of the lock mechanism determines whether the mechanism is in a locked or unlocked mode. Normally, the tumblers are pre-set to cooperatively engage and be positioned by a key having a specifically configured biting. This key is therefore used to lock and unlock the assembly and accordingly the closure on which it is mounted.

In many applications such as hotels, apartment houses, safety deposit boxes in banks and other areas where a large number of lock assemblies are needed, it is often very inconvenient to pre-set each assembly to fit a different key. However, this is often necessary to insure security and safety as desired. In hotels and the like the custodian must keep an extremely large number of keys on hand since each door has a different pre-set combination and since each occupant of the hotel would naturally insist upon his own key to get into his room. The custodian of the hotel must also keep one or more extra keys to get into the room in an emergency or when the occupant has misplaced his key.

In order to overcome the problem, of the hotel or similar facility, of maintaining an extremely large number of keys, it has been contemplated to devise a variable set lock assembly in order to overcome the problem of utilizing a large number of lock-unlock key combinations. Such a structure is found in U.S. Pat. No. 2,818,723 to Morris J. Levin. This patent is directed to a lock assembly designed to automatically adjust itself to an unlimited number of key combinations. More particularly, in the structure disclosed and claimed in that application, a key is inserted to close the lock thereby automatically setting up a locking combination which can only be opened by the same key or such other key as permitted by the locking combination set up. This structure has the advantage of eliminating the necessity of separate combination determining parts requiring the use of cams, gears, detents and the like. As evidenced by the Levin patent, variable combination locks are known in the prior art.

The majority of these locks however still have inherent problems such as relatively complex structures necessitating a relatively large expenditure upon purchase of these types of assembly and/or a failure of these lock assemblies to be durable and reliable over a long period of use. In addition these type of variable combination lock assemblies still require a large number of keys to be maintained by the custodian of a hotel type building in order to insure ready access to the rooms or closure which the lock assemblies are connected to.

Accordingly, it can be seen that there is a need for a relatively simple, durable lock assembly capable of being purchased and maintained at relatively small expense. In addition such a structure should be designed to eliminate the need for maintaining an extremely large number of keys by providing for the locking-unlocking combination to be set in predetermined position each time the key is inserted into engagement with movably positioned tumblers.

This would allow the occupant of the hotel or user of this type of lock assembly to carry around with him his own set of key applicable for any lock assembly capable of being automatically preset in the manner described above. Such a procedure would lead to more efficient and convenient access to various closures of the type previous described.

SUMMARY OF THE INVENTION

This invention relates to a locking assembly having a plurality of movable tumblers arranged in cooperative engagement with one another and also positioned in cooperation with a slave and master key which automatically resets the tumbler into a predetermined locking-unlocking position respectively, upon insertion of the key into separate keyways.

More particular, locking assemblies of the present invention comprises a plurality of key plugs each arranged in cooperating relation to the other and each including a keyway. A set of master tumbler means are arranged in intersecting relation to the first keyway associated with a key plug. The set of master tumbler means comprises a plurality of master tumblers each communicating with the first keyway such that a first or master key inserted in the first keyway positions each of the plurality of master tumblers in a predetermined locking or unlocking position.

Similarly, a set of slave tumbler means are positioned in cooperative relation with a second keyway located in another key plug positioned in cooperation with a key plug housing the first keyway. The slave tumbler means comprises a plurality of slave tumblers each intersecting the second keyway and movably positioned relative to a correspondingly arranged master tumbler. More specifically, each of the plurality of master tumblers are positioned to movably engage one of the plurality of slave tumblers. Both the master tumblers and slave tumblers are biased into a predetermined position. The first and second keyway are arranged relative to these tumblers so as to move them against the biasing force and into a pre-set combination. Obviously the position of each of the plurality of tumblers is determined by the biting of the particular keys used. This particular combination allows the tumbler to be automatically reset upon the insertion of any key having a different biting.

One embodiment of the present invention includes the uppermost extremity of each of the slave tumblers having a protrusion formed thereon. This protrusion is designed to travel in a substantially vertical reciprocating fashion in a longitudinal groove formed on the lower end of each master tumbler. A transverse slot is formed in communicating relation with the longitudinal groove and the protrusion. The cooperating pairs of slave and master tumblers are positioned in an unlocking position when the protrusion is in direct communicating relation with both the longitudinal groove and transverse slot. Rotation of one of the key plugs relative to the other causes the protrusion of each slave tumbler to travel out of the longitudinal groove and through the longitudinal slot thereby unlocking the lock assembly.

Another embodiment of the present invention comrises both extremities of the slave tumbler designed to operatively engage apertures located in the master tumbler adjacent to the extremities of the slave tumbler. Both the plurality of slave tumblers and the plurality of master tumblers are designed to move in a reciprocal such that arranging cooperative pairs of slave and master tumblers in a locking mode can be accomplished by the insertion of either extremity of the slave tumblers into an adjacently positioned aperture in a correspondingly arranged master tumbler.

In another embodiment of the present invention one of the plurality of key plugs is rotatably mounted relative to adjacently positioned and cooperatively arranged key plug. The slave tumbler means is reciprocally mounted relative to the master tumbler means and rotatably engages it thereby providing a camming action therebetween. The master tumbler means may then be locked into place by a securing means once properly positioned by a key having a predetermined biting. This securing means maintains the master tumbler means in the predetermined, pre-set position such that the key may be removed therefrom. Similarly, the slave tumbler may be properly positioned relative to the master tumbler means than the use of the same or another key having a predetermined biting. Auxiliary tumblers are arranged in communicating relation with the key which is inserted in the key plug associated with the slave tumbler means whereby the auxiliary tumbler, upon engaging the key are moved to an unlocked position dependent upon the pre-set position of both the slave and master tumbler means.

In any of the above outlined structure, key removal prevention means may be provided. This includes a notch being formed on the outer extremity of each of the keys whereby rotation of one key plug relative to each of the keys whereby rotation of one key plug relative to the other causes the key in the first key plug to engage a circular shaped flange when not in its locked or unlocked position. Rotation of the first key plug in this manner causes an extension means to rotate a finger into and out of the notch found in the key positioned in the keyway of the associated or second key plug.

Additional structure may also be provided to prevent the insertion of a key in any key slot associated with the subject lock ing assembly. This shield means may comprise a shield portion and a latch portion located on opposite sides of a closure whereby the shield portion is placed over a predetermined key slot by activation of the latch portion on the opposite sides of the closure. Positioning of the shield in this manner of course prohibits anyone from entering a given key slot with a key.

The invention accordingly comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawing in which:

FIG. 1 is a side sectional view of a lock assembly of the present invention.

FIG. 2 is a front sectional view taken along lines 2--2 of FIG. 1.

FIG. 3 is a detailed sectional view of cooperating slave and master tumbler.

FIG. 4 is a front sectional view of another embodiment of the present invention showing cooperating master and slave tumblers.

FIG. 5 is a front sectional view of a key removal prevention means of the present invention.

FIG. 6 is a detailed view of one extremity of a key associated with the structure of FIG. 5 taken along lines 6--6 of FIG. 5.

FIG. 7 is another embodiment of the tumbler securing means associated with the present invention.

FIG. 8 is a side view of shield means of the present invention.

Similar reference characters refer to similar parts throughout the several views of the drawings.

DETAILED DISCUSSION

This invention relates to a locking device generally indicated as 10 which comprises a housing 12 in which are mounted a plurality of key plugs 14 and 16 each arranged in substantially adjacent and cooperative relation to one another. Each of the key plugs comprises a keyway or key slot 18 and 20 designed to receive a key 22 and 24 respectively therein.

Slave tumbler means generally indicated as 26 comprises a plurality of slave tumblers 28 each of which are movably mounted relative to key plug 16 or the key plug with which they are associated. In addition, each of the slave tumblers 28 are arranged in communicating relation with the keyway 20 so as to be movably engageable with a key inserted therein.

Similarly, the locking device of the present invention further includes master tumbler means generally indicated in FIG. 1 at 30 and comprising one or more master tumblers 32. The master tumbler are also movably mounted relative to key plug 14 and are arranged in communicating relation with key slot 18 so as to be movably engagable with a key 22 inserted therein.

With reference to FIGS. 1-4 each of the slave tumblers 28 are positioned to movably engage correspondingly positioned master tumblers 32 and each of the cooperative pairs of slave and master tumblers are mounted to reciprocally move relative to one another. Referring to FIGS. 2, 3 and 4 each of the slave tumblers 28 and each of the master tumblers 32 are biased by a biasing means in the form of springs 34 and 36 respectively. The force of the springs against their respective tumblers causes these tumblers to be biased in relative position to one another such that the locking device 10 assumes a locked mode until both slave and master tumbler means cooperatively engage keys inserted in their respective keyways. These keys of course serve to move the tumblers against the biasing force exerted by the springs cooperating therewith.

In the embodiment shown in FIGS. 2 and 3 the upper extremity of each slave tumbler includes a protrusion 40 and the lower portion of each master tumbler includes a longitudinal slot 42 and a transverse groove 44 both of which are positioned in cooperative relation to protrusion 40. More particularly, protrusion 40 is positioned to be in communicating relation with both groove 42 and slot 44. In operation, key 22 which may be considered the master key is inserted in keyway 18 and thereby movably engages each of the master tumblers 32 and positions them in a predetermined position depending upon the biting 50 of the key 22. This serves to "set" the unlocking combination for the slave tumbler means and the master tumbler means. When the closure or structure on which the locking device 10 is mounted, is desired to be opened or unlocked a second key or slave key 24 is positioned in keyway 20 thereby movably engaging and positioning each of the slave tumblers 28. The biting of the keys 22 and 24 are correspondingly configured such that protrusion 40 will be positioned at the junction of groove 42 and slot 44 and in communication with both. This allows protrusion 40 to travel in groove 44 upon rotation of key plug 16 as indicated by directional arrow 52. Rotation of key plug 16 occurs in the conventional manner by merely rotating the head of key 24.

Similarly, the embodiment of FIG. 4 comprises each of the slave tumblers 32 having a somewhat different configuration which includes apertures 54 and 56 rotated adjacent the opposite extremities 58 and 60 of slave tumblers 28. The operation of this embodiment is of course similar in that insertion of the keys 22 and 24 serves to position each of the master tumblers 32 and each of the slave tumblers 28 respectively so that the extremities 58 and 59 are not inserted in apertures 54 and 56 respectively. It is of course obvious that if either extremity 58 or 59 is in its adjacently located aperture, the locking device 10 will still be in its locked mode and rotation of plug 16 will be prevented.

A key removal prevention means may be utilized with each of the embodiments of the present invention and is more particularly disclosed in FIGS. 5 and 6. This key removal prevention means generally indicated as 60 comprises a yoke means 62 partially surrounding plug 16 and being pivotally mounted about pivot pin 64. An arm 66 may be integrally attached to the yoke 62 and includes a finger 68 attached at the free end thereof. The key removal prevention means 60 further includes a button 70 mounted on the outer peripheral surface of plug 16 and is designed to movably engage the inner surface of yoke 62 in a cam-like fashion. A flange 72 is mounted adjacent the lower portion of plug 16 in communicating relation or adjacent to the key slot in which a key 24 is placed. Upon rotation, in the conventional manner, of plug 16 and key 24, a notch 74 engages flange 72 thereby preventing the removal of key 24 except when in its upright, locked or unlocked position as shown in FIG. 5. Similarly, the rotation of plug 16 causes the button 70 to pivot yoke 62 about pin 64 thereby positioning finger 68 in the slot 74 of key 22 associated with plug 14. This prevents the removal of key 22 until key 24 is again in its upright position which serves to position the yoke 62 in its proper relative position.

With regard to FIG. 7, a tumbler securing means may be utilized to secure one set of the tumblers in a pre-set combination by maintaining the position of these tumblers once there combination has been determined by the positioning of a key in the tumbler means associated with the securing means. More particularly, once each of the master tumblers 14 are arranged in pre-set position against the biasing force of biasing springs 36 due to key 24, the securing means generally indicated in FIG. 7 as 90 is activated. This securing means 90 includes a rotatable cam 92 movably positioned between surfaces 94 and 96 of housing member 15. Since the securing assembly 90 is not mounted directly on any of the tumbler means the locking engagement of securing means 90 maintains tumbler 32 in its pre-set position against the biasing force of springs 36. Accordingly, when it is desired to unlock the assembly, slave key 24 is inserted in keyway 20 thereby positioning auxiliary tumbler means 23 in its unlocking position relative to the pre-set position to tumbler 32.

In addition to the above, a shield means may be provided to prevent the insertion of any key in any of the keyways of the adjacently positioned plugs. The shield means is generally shown in FIG. 8 as 96 and includes a first shield portion 98 and a finger latch portion 100 located on opposite sides of a closure 102. The shield portion 98 is attached along one edge to shaft 104 interconnected to both the shield portion 98 and the finger latch portion 100. Activation of the finger latch portion 100 serves to pivot the shield portion 98 located on the opposite side of the closure 102 over an entrance of a keyway associated with one of the adjacently located key plugs 17 or 19. This will prevent the unauthorized insertion of a key into one of the plugs and thereby prevent the unauthorized opening of a closure or unlock of a locking device.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the invention and in the construction set forth without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Claims

Now that the invention has been described, what is claimed is:

1. A lock assembly of the type having a variable locking-unlocking combination, said lock assembly comprising: a plurality of key plugs mounted in cooperative relation to one another and each having at least one keyway; master tumbler means comprising a plurality of master tumblers movably mounted in cooperative relation to said one keyway of a first of said plurality of key plugs; and slave tumbler means comprising a plurality of slave tumblers movably mounted in cooperative relation to said one keyway of a second of said plurality of key plugs, each of said plurality of slave tumblers arranged in movable engagement with correspondingly positioned master tumblers, said first and second key plugs positioned in operative relation to one another such that locking and unlocking positions of each of said tumbler means is determined by the biting of a first and second key inserted in said one keyway of said first and second key plugs respectively, whereby the locking-unlocking combination of said lock assembly may be varied dependent upon the biting of the keys, each of said slave tumblers including a protrusion and each of said master tumblers including an elongated slot positioned to operatively engage said protrusion on the correspondingly positioned slave tumbler, each of said master tumblers further including a transverse slot formed thereon and arranged in communicating relation with said elongated slot and said protrusion, whereby cooperating master and slave tumbers are positioned in an unlocking mode when said protrusion is positioned to engage said transverse slot.

2. A lock assembly as in claim 1 wherein the relative position of each slave tumbler with its correspondingly arranged master tumbler is defined by the biting of said second and first key respectively.

3. A lock assembly as in claim 1 further comprising biasing means connected to each of said slave and master tumblers, such that said slave and master tumblers are biased into predetermined working relation with one another.

4. A locking assembly as in claim 1 wherein the biting of said first and second keys each have the same configuration.