Rotary release magnetically operated lock
SUMMARY OF THE INVENTION 
     The present invention generally relates to magnetically operated locks. 
     More specifically, the present invention is directed towards a magnetically operated lock, which is characterized as including a plurality of pivotally supported tumbler pins having magnetically attractable ends constrained for movement along the paths of travel directed essentially radially of a shaft. The shaft serves to rotatably support a release plate having a plurality of composite slots each of which is arranged in association with and adapted to receive the magnetically attractable end of one of the tumbler pins. Each composite slot includes a radially extending locking portion alignable with the path of travel of one of the tumbler pins and a transversely extending unlocking portion arranged to intersect the locking portion at a lock combination setting position arranged at some point other than adjacent the ends of the locking portion. The magnetically attractable ends of the tumbler pins normally engage with the side walls of the locking portions of the composite slots in order to prevent unlocking rotation of the release plate. When the ends of the tumbler pins are pivoted into their combination setting positions by the application of a magnetic key to the lock, the ends of the tumbler pins are disposed in alignment with the unlocking portions of the composite slots, thereby to free the release plate for unlocking rotational movement. 
    
    
     DRAWINGS 
     The nature and mode of operation of the present invention will now be more fully described in the following detailed description taken with the accompanying drawings wherein: 
     FIG. 1 is an exploded perspective view of a lock employing the present invention; 
     FIG. 2 is a vertical sectional view taken through an assembled lock, when in a locked condition; 
     FIG. 3 is a sectional view taken generally along the line 3--3 in FIG. 2; 
     FIG. 4 is a sectional view similar to FIG. 2, but showing the lock in an unlocked condition; 
     FIG. 5 is a sectional view taken generally along the line 5--5 in FIG. 4; and 
     FIG. 6 is a sectional view of a magnetic key employed for controlling operation of the lock of the present invention. 
    
    
     DETAILED DESCRIPTION 
     A lock constructed in accordance with the present invention is generally designated as 10 in FIGS. 1, 2 and 4. More specifically, lock 10 comprises a lock casing or housing 12 defined by a face or front closure plate 14, a base or rear closure plate 16 and a cylindrical side wall part 18, which serves to rigidly interconnect plates 14 and 16 in a spaced, generally parallel relationship; a mounting plate 20 for pivotally supporting a plurality of tumbler pins 22; a tumbler pin guide plate 24; and a lock release assembly 26 including a supporting pin or shaft 28, a release plate 30 and an operator-release lever 32. 
     Lock 10 is adapted to be unlocked by means of a generally U-shaped key 34 removably insertable within a like configured key orienting recess 36 defined by face plate 14. A plurality of permanent magnets 38 are arranged within the nonmagnetic body of key 34 for the purpose of placing tumbler pins 22 in their respective combination setting positions when the key is inserted into recess 36, whereby to free assembly 26 for rotation between its locked and unlocked positions shown in FIGS. 3 and 5, respectively. The required placement of magnets 38 within key 34 will be determined by the internal structure of lock 10, as will hereinafter become apparent. 
     By reference to the drawings, it will be understood that mounting and guide plates 20 and 24 are positionally fixed in any suitable manner within lock casing 12, such that they are disposed relatively adjacent and essentially parallel to rear plate 16 and face plate 14, respectively. The spacing between mounting plate 20 and rear plate 16 may be suitably determined, as by forming the latter with a spacer sleeve 16a, whereas the spacing between face plate 14 and guide plate 24 may be suitably determined, as by forming the latter with a spacer sleeve 24a. The spacing between these several plates must be at least sufficient to permit free pivotal movements of the tumbler pins without engagement of their upper and lower ends with plates 14 and 16, respectively. 
     Rear plate 16, mounting plate 20 and guide plate 24 are formed with vertically aligned and essentially centrally disposed through openings 40, 42 and 44, respectively, for rotatably receiving pin shaft 28. If desired, rotary and thrust bearing supports 46 and 48 for pin shaft 28 may be fitted within openings 40 and 44, respectively. 
     Referring to FIGS. 1-3, it will be understood that tumbler pins 22 preferably have their lower end portions pivotally secured within mounting plate openings 50 by any suitable means such as pin shafts 52 and have their upper or magnetically attractable end portions slideably received one in each of a plurality of guide slots 54, which are formed in guide plate 24 and arranged in vertical alignment with openings 50. With this arrangement, tumbler pins 22 are &#34;top heavy&#34; or unbalanced and therefore biased by the force of gravity to pivot within vertical planes extending essentially radially of the axis of rotation of pin shaft 28; the radially extending side walls of slots 54 serving to guidingly support or constrain the upper ends of the tumbler pins against movement transversely of their paths of travel. When guide plate 24 is viewed in plan, the upper end portions of pins 22 may be considered as undergoing reciprocating movements along straight line paths of travel. 
     Release plate 30, which is rigidly fixed to the upper end of pin shaft 28 intermediate face plate 14 and guide plate 24 is formed with a plurality of tumbler pin receiving composite slots 60 corresponding in number to the number of slots 54 formed in guide plate 24. Specifically, each of composite slots 60 includes an elongated radially extending locking slot portion 62, which is disposed in vertical alignment one with each of slots 54 when plate 30 is in its locked position shown in FIGS. 2 and 3, and an elongated, generally transversely extending unlocking slot portion 65, which is arranged to intersect its associated locking slot portion 62 at a tumbler pin combination setting position arranged at some point which is preferably other than immediately adjacent the opposite or radially inner and outer ends of locking slot portion 62. The unlocking slot portion 64 should be spaced from one or the other end of its associated locking slot portion 62 sufficiently to permit a side wall portion of the locking slot portion to be arranged for locking engagement with the upper end portion of its associated tumbler pin when the latter is in either of its rest-locked positions, such as may be defined by engagement thereof with the opposite ends of the locking slot portion and/or its associated slot 54. Preferably, the ends of slots 54 and 62 are disposed on radially directed opposite sides of their associated tumbler pin pivot axis, or on opposite sides of their associated tumbler pin when it vertically upstands, in order to permit the tumbler pins to &#34;fall&#34; under the influence of gravity randomly in opposite directions from a vertical upstanding position into either of two rest positions arranged on opposite sides of their combination setting positions along their respective paths of travel. 
     It will be appreciated that the possible number of combination setting positions for any tumbler pin of a given length and diameter is maximized by the illustrated construction, wherein such tumbler pin is pivotally supported immediately adjacent one of its ends and engages with release plate 30 immediately adjacent an opposite end. 
     Again referring to FIGS. 2 and 3, it will be seen that when lock 10 is locked or in a rest condition and assumes its illustrated vertically disposed position, the tumbler pins tend to be unbalanced and thus move away from a vertically upstanding position and fall in a random manner under the influence of gravity towards their rest positions arranged adjacent one or the other of the ends of vertically aligned slots 54 and 62. If lock 10 were to be used or installed in a position other than that illustrated in the drawings, eg., the lock installed such that the axis of pin shaft 28 extends horizontally, then the force of gravity would tend to move the tumbler pins such that each may assume only one rest position defined by one or the other ends of their associated slots 54. On the other hand, if lock 10 were to be inverted from the position shown in the drawings, the tumbler pins would tend to hang downwardly and would normally have their formerly upper ends disposed in rest positions intermediate the opposite ends of the slots. While this latter orientation of the lock is not preferred, it could of course be compensated for by insuring that unlocking slot portions 64 do not intersect locking slot portions 62 at tumbler pin combination setting positions, which would correspond to the single rest positions of the tumbler pins, if all were to assume a vertically disposed parallel relationship. Also, even in the case of a lock disposed in the position illustrated in the drawings, it would be possible to provide only one rest position for each tumbler pin as by radially shifting slots 54. 
     Thus, when lock 10 is in a locked condition, tumbler pins 22 are normally disposed in rest positions adjacent the opposite ends of locking slot portions 62 and out of alignment with unlocking slot portions 64. Accordingly, any attempt to rotate lever 32 will be resisted by engagement of the side walls of locking slot portions 62 with the upper end portions of tumbler pins 22. When key 34 is inserted within recess 36, the upper end portions of the tumbler pins are magnetically attracted and are thereby moved into their combination setting positions, which are designated as 22a in FIG. 3 and correspond to the points of intersection of their associated unlocking and locking slot portions 64 and 62. When this occurs, lever 32 and thus assembly 26 are freed for rotation in an unlocking direction indicated by arrow 70 in FIG. 5. During unlocking rotation of plate 30, the tumbler pins will move relatively within unlocking slot portions 64 until release plate rotation is arrested and the unlocked condition of the lock 10 thereby defined, such as for instance by engagement of the closed ends of unlocking slot portions 64 with the tumbler pins. During relative movement of the tumbler pins within unlocking slot portions 64, the illustrated configurations of such unlocking slot portions force the tumbler pins to move within guide plate slots 54 in a direction determined by the angle of intersection between the unlocking and locking slot portions. 
     For purposes of reference, a preferred lock design is shown in the drawings as being provided with seven identical tumbler pins 22, which are arranged to pivot within seven vertically disposed planes, wherein adjacent planes intersect one another at angles of essentially 45°. This arrangement requires that seven magnets 38 be encapsulated within key 34 and arranged one along each of seven radially extending imaginary lines designated as I-VII in FIG. 6; lines I-VII being orientated such that they will be disposed in vertical alignment with slots 54 when key 34 is inserted in recess 36. The positioning of magnets 38 lengthwise of lines I-VII will be such that each of the magnets is arranged to essentially overlie the junction or point of intersection of the locking and unlocking slot portions of an associated composite slot 60 when release plate 30 is in its locked position. To simplify manufacturing or combination setting procedures, each of magnets 38 is arranged in one of several possible positions, which are designated as 38&#39; in FIG. 6 and shown as being arranged at the intersections of radial lines I-VII and circles a-d. Circles a-d are disposed concentrically of the center 34&#39; of key 34, which is adapted to be disposed in alignment with the axis of shaft 28 when the key is fitted within recess 36. Thus, only one key, which has its magnets 38 arranged in the specific pattern illustrated in FIG. 6, will permit a release plate 30, which has the specific composite slot configuration illustrated in FIG. 3, to be rotated into unlocked position. If any one of magnets 38 were to be omitted or placed in one of the other possible magnet positions 38&#39;, its associated tumbler would not be brought into its combination setting position and would thus be effective to prevent unlocking rotation of the release plate. 
     Lever 32, may if desired, be manually movable and coupled to a lock bolt, shackle or the like, not shown. Alternatively, lever 32 may be employed merely as a blocking element arranged to selectively interfere with the operation of a lock bolt, shackle or the like, which is under the control of a separate manually operable device, such as a push button, door knob, etc. Thus, the present invention is not restricted in applicability to the mechanism with which lever 32 is associated. 
     Further, it will be understood that the illustrated lock construction may be departed from in several ways without changing its overall mode of operation. Specifically, it is contemplated that spring devices or other suitable means may be employed either in cooperation with or in opposition to the force of gravity to bias the tumbler pins into their rest positions. Also, the tumbler pins may be pivotally supported at a point other than immediately adjacent their lower ends and/or the release plate may be arranged to engage portions of the tumbler pins disposed other than immediately adjacent their opposite ends and/or the portions of the tumbler pins subject to magnetic attraction and engaged with the release plate may be on opposite sides of the portion of the tumbler pins supported by pin shafts 52.