Patent Publication Number: US-6902214-B2

Title: Electromechanical locking method and device

Description:
FIELD OF THE INVENTION 
     The present invention broadly concerns locking methods and systems. More particularly, the present invention is directed to electromechanical devices that may be employed to secure two structures together which may otherwise move relatively apart from one another. The present invention is also directed to a method of a electromechanically locking two structures together. This invention is especially adapted for use in electromechanically locking a door. 
     BACKGROUND OF THE INVENTION 
     The ability to lockably secure two structures together to permit or prevent relative movement therebetween has been a goal of many locking systems. A plethora of different locking mechanisms have been developed over the course of history. These include key actuated locks, combination locks, code activated locks and the like. 
     Many types of locks are associated with doors in order to selectively lock a door in a closed position. Authorized personnel are provided with a key or combination to the lock so that they may selectively unlock the door and move it to an open position. In some instances, doors are locked in such a way as to allow monitored access. Here, a guard monitors the door to an entryway. When an authorized person seeks access, the guard initializes a switch which deactivates the lock so that the door can be opened. Such systems are often employed at offices for controlling employee access, in apartments, wherein a tenant may initialize a switch that deactivates the locking device to allow entrance of a guest into the building and other related applications. 
     One type of electrically controlled lock employs an electromagnet that is typically mounted to a door casing. A ferromagnetic armature is attached to the door and positioned so as to come in contact with the electromagnet device on the casing. The electromagnet is of such strength that a person may not readily open the door when the electromagnet is activated due to the strength of the magnetic attraction of the electromagnet for the armature. As security interests have heightened, it has become increasingly desirable that greater force be provided for these magnetic locks to secure the door and the casing. Accordingly, the strength of the electromagnets has been proportionately increasing. Such increase in strength, however, is not without its drawbacks. While some technological advances have been made in materials, it has been the usual case that increasing the strength of the electromagnet results in utilizing increasingly higher gauss magnets. This naturally increases the cost of the magnet as well as power consumption should the magnet be continuously energized with access being granted by de-energizing the magnet. In addition to these disadvantages, increasing the size of the electromagnet increases the size of the assembly secured to the door casing. 
     The present invention addresses these disadvantages by providing an electromechanical locking system and method that utilizes an electromagnet in conjunction with mechanical structure to accomplish the selective locking of two structures together. Thus, it is able to provide a high strength of resistant to breach while at the same time reducing the size of the electromagnetic device. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a new and useful electromagnetic lock that may be used to secured two structures, such as a door and its casing, together while permitting the structures to be moved apart from one another as desired. 
     Another object of the present invention is to provide a new and useful electromechanical locking system which can be employed, for example, with security doors as well as a door employing such electromechanical lock. 
     It still a further object of the present invention to provide a new and useful method for electromechanically locking first and second structures together. 
     A further object of the present invention is to provide an electromechanical locking structure that can be produced at a reduced size and cost while maintaining a high locking strength. 
     According to the present invention, then, an electromechanical lock is adapted to selectively permit first and second structures from moving apart from one another when in a first state and to prevent said first and second structures from moving apart when in a second state. Broadly, the electromechanical lock includes a latching assembly adapted to mount to the first structure and a catch piece adapted to mount to the second structure. The latching assembly and the catch structure are positionable such that the catch piece can be docked in a receive state in the latching assembly. 
     The latching assembly includes at least one latch element movable between a capture state wherein the catch piece becomes mechanically engaged thereby and a release state wherein the catch piece is disengaged thereby. The latching assembly includes an arming member that is movable between a first position and a second position. The arming member, when in the first position, engages the latch element whereby the latch element is in the release state. The arming member, when in the second position, permits the latch element to move into the capture state. The latching assembly includes a biasing element associated with the arming member that is operative to urge the arming member into the first position with the first force. 
     The invention also includes an electromagnetic device that is switchable between an “on” condition and a “off” condition. This electromagnetic device is operative to magnetically co-engage the arming member and the catch piece when the catch piece is in the received state and the electromagnetic device is in an “on” condition. This engagement is with a sufficient magnetic force to overcome the first force whereby movement of the catch piece away from the received state while the electromagnetic device is in the “on” condition results in the latch element moving into the capture state. 
     The electromagnetic lock of the present invention may be mounted in a housing that includes a base and a cover. When the cover is secured on the base, the housing has an interior with an entryway sized to receive the catch piece. The latch element is mounted for rotation within the housing. In one embodiment, the latching element has a pair of opposed projecting trunnions. A base wall portion of the housing and the cover are each in spaced-apart opposed relation to one another, and the base wall portion and the cover are each provided with seats for rotatably receiving and mounting the trunnions. A plurality of latch elements may be provided in the housing. 
     The latch element can take a variety of forms and may be operated in several different manners. In once instance, the latch element may be biased or in the capture state. The latch element can be formed as a pawl having a cam surface that acts to move said latch element between the release and capture state. This cam surface can be formed by an inclined plane portion on the latch element in which case the arming member includes a portion that slides along the inclined plane to allow the latch element to move between the release state and the capture state when the arming member moves between the first and second positions. The latch element can be formed as a pawl having a slotted opening. Here, the arming member can include a portion that is received in the slotted opening and acts to move the latch element between the release state and capture state when the arming member moves between the first and second positions. Preferably, the arming member is spring biased toward the first position. 
     The catch piece can be formed as a variety of structures, but one such structure is an armature plate that includes a lip portion operative to be engaged by the latch element when it is in the received state. The electromagnetic device can be secured to the arming element or to the catch piece. When secured to the arming element, the arming element can form a core for an electrically conductive coil so as to form part of the electromagnetic device. 
     The electromechanical lock of the present invention, while useful for preventing and permitting any two suitable structures from moving apart from one another, it is especially adapted to selectively permit the locking of a door in its casing. Thus, the present invention is also directed to an access door for an opening in a structure. Here, the access door includes a casing adapted to mount in the opening and a door adapted to mount in a casing and movable between an open state and a closed state. The invention then includes electromechanical lock described generally above. 
     The electromechanical lock, as generally described above, can also be employed in a electromechanical locking system that is adapted to connect to a source of electrical power and to selectively permit one or more first and second structures from moving apart from one another when in a first state and to prevent the structures from moving apart from one another when in a second state. This locking system includes one or more electromechanical locks, as generally described above, as well as a controller that is operative to selectively switch electromechanical lock(s) between the “on” and the “off” state. 
     Finally, the present invention also includes a method for electromechanically locking first and second structures together. The method broadly includes a first step of mounting a latching means including at least one of mechanical latch element onto a first structure with this latch element movable between a capture state and a release state. The method includes the step of biasing the latching element into the release state with a first force. The method also includes the step of mounting a catch means on the second structure. The method encompasses the docking of the catch means with the latch means together in a received state and mechanically coupling the latch element and the catch means with an electromagnetic device that is switchable between a “on” condition and a “off” condition. Thus, when electromechanical device in a “on” condition, the electromagnetic device magnetically co-engages the latching means and the catch means with sufficient magnetic force to overcome the first force whereby movement of the catch means away from the received state results in said latching means moving into the capture state. Further, when the electromagnetic device is in the “off” condition, the latching means and the catch means may be disengaged with said latch element remaining in the release state. 
     The present invention will become more readily appreciated and understood from a consideration of the following detailed description of the exemplary embodiments when taken together with the accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the electromechanical lock according to a first exemplary embodiment of the present invention secured to first and second structures with a power supply and controller shown in diagrammatic view therewith; 
         FIG. 2  is a perspective view of the housing which contains the latching assembly according to the first embodiment of the present invention; 
         FIG. 3  is a perspective view of the arming element and electromagnetic device according to the first embodiment of the present invention; 
         FIG. 4  is a cross-sectional view taken about lines  4 — 4  of  FIG. 3 ; 
         FIG. 5  is a plan view of the base used to form the housing of  FIG. 2 ; 
         FIG. 6  is a plan view showing the interior of the cover used to form the housing of  FIG. 2 ; 
         FIG. 7  is a perspective view of a latching element according to the first exemplary embodiment of the present invention; 
         FIG. 8  is a side view in elevation of the latching element of  FIG. 7 ; 
         FIG. 9  is an exploded front view in elevation showing the assembly of the base of  FIG. 5  with the cover of  FIG. 6  along with a pair of latch elements such as those shown in  FIGS. 7 and 8 ; 
         FIG. 10  is an end view in cross-section taken about lines  10 — 10  of  FIG. 9 , when assembled; 
         FIG. 11  is a perspective view showing the arming member and the electromagnetic device of  FIG. 3  received in the base of  FIG. 5  along with one latch element as shown in  FIG. 7 ; 
         FIG. 12  is a top view in elevation showing the mounting of the arming member and electromagnetic coil of  FIG. 3  mounted in the base of  FIG. 5 ; 
         FIG. 13  is a top view in elevation showing a pair of latching elements of  FIG. 7  received in the base of FIG.  5  and shown in a release state; 
         FIG. 14  is a top view in elevation, similar to  FIG. 13 , but showing the latch elements in a capture state; 
         FIG. 15  is a perspective view of a catch element according to an exemplary embodiment of the present invention; 
         FIG. 16  is a top view in elevation showing the latching assembly mounted on a first structure, such as a door casing, and the catch piece mounted on a second structure, such as a door, with the catch piece being docked in a received state within the latching assembly and with the latch elements in the release position; 
         FIG. 17  is a top view in elevation showing the structure of  FIG. 16  with the electromagnetic device being placed in the “on” condition and a second structure moved slightly away from the first structure to show the movement of the latch elements into the capture state thereby prevent removal of the catch piece from the receive state; 
         FIG. 18  is a top view in cross-section, similar to  FIG. 16  showing a second embodiment of the present invention in the release state; 
         FIG. 19  is a top plan view in elevation, similar to  FIG. 18 , but showing the latch elements in a capture state to prevent the catch piece from being removed from the receive state in the latching assembly; 
         FIG. 20  is a top view in elevation, similar to  FIG. 19 , but showing the action of electromechanical lock when the electromagnetic device is placed in the “off” condition so that the catch piece may be removed from the latching assembly with the latch elements shown in the release state; 
         FIG. 21  is a top plan view of yet another alternative embodiment of the present invention, here with the electromagnet being associated with the catch piece; 
         FIG. 22  is a top view in elevation diagramming yet another embodiment of the present invention with the latch pieces shown in the release state; 
         FIG. 23  is a top plan view, similar to  FIG. 22 , but showing the latch elements moving into the capture state; 
         FIG. 24  is a perspective view of an alternative catch piece; and 
         FIG. 25  is a perspective view of yet another alternative catch piece. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     The present invention is directed to an electromechanical lock that can be used to selectively two structures together. Thus, the electromechanical lock selectively allows the structures to move apart from one another but will also selectively retain them together in a closed condition. The electromechanical lock of the present invention is particularly adapted as a door lock to selectively lock the door in a closed position yet permit the door to move into an open position relative to its casing. This includes both swinging doors and sliding doors. The present invention includes a door that incorporates the electromechanical lock as well as a system which includes a controller that is connected to a power source so as to control activation and deactivation of the electromechanical lock. The present invention also contemplates a method of electromechanically securing two structures together by the steps inherent in the electromechanical structures described below. 
     A first exemplary embodiment of the present invention is shown in  FIGS. 1-17 . With reference to  FIG. 1 , an electromechanical lock  10  is shown attached to a first structure in the form of a door  12  and a casing  14  which, for example, mounts in a structural portion of a building, such as an entryway door opening, an interior door, or the like. Electromechanical lock  10  includes a latching assembly  20  and a catch piece  90  as more thoroughly describe below. By “latching assembly” it is meant any structure that is operative to receive and engage a catch piece and can encompass a multitude of structures as should be understood by the ordinarily skilled person after reading the present disclosure. Likewise, “catch piece” means any piece of desired shape, structure or configuration that is received by the latching assembly and that can be lockably retained thereby in a releasable manner. In order to attach latching assembly  20  to casing  14 , a plurality of bolts  16  are provided which extend through bores  18  in latching assembly  20  and mount into the edge of casing  14  as is known in the art. This mounting is similar to existing controlled access security locks of the electromagnetic type. 
     An electromagnetic arming member is received in latching assembly  20 , and this combination is shown in  FIGS. 3 and 4 . In these Figures, a core  22  is formed by three fins  24 ,  25  and  26  joined by a base web  27  along one side thereof. An electrical coil  28  is wound within core  22  such as around fin  25 . Electrical coil  28  is preferably a copper winding and can consist of one or a plurality of individual coils such as component coils  29  and  30  formed of suitable conductive windings, usually metal, such as copper. Core  22  can be of any type known in the art and may be solid or laminated as known in the magnetic art. Solid cores are typically made of magnetically permeable materials, laminated cores are typically constructed as flux-directing layers of permeable steel. Core  22  and coil  28  thus form an electromagnet that can be switchable connected to a power supply  100  switchably operated by a controller  102 , as is shown in FIG.  1 . 
     A housing for latching assembly  20  is formed by a base  32  and a cover  50  respectively shown in  FIGS. 5 and 6 . Base  32  includes a base wall  34  and a side wall  36  formed by side wall portions  38 ,  39  and  40 . Blocks  42  are located at the corners of base  32  and are formed integrally therewith and are provided with bores  18  for bolts  16 . An L-shaped rib  44  extends from each of the blocks  42  located at the front of base  32 . These ribs  44  project towards one another. A pair of seats  46  are located proximately to each respective block  42  at the rear of base  32  on base wall  34  and side portion  40 . Seats  46  each have a cylindrical cavity  47  formed therein. A pair of posts  48  project upwardly of base wall  34  centrally thereof and provide guides, as described below. 
     With reference now to  FIG. 6 , cover  50  includes a cover panel  51 . Panel  51  that is surrounded on three sides by a side rib  52 . Blocks  54  are located at each corner of cover  50  and include bores  18  for bolts  16  noted above. A pair of seats  56  are disposed along a back edge of cover  50  and each have a cylindrical cavity  57  formed therein. A pair of posts  58  are disposed on cover panel  51  and are centrally located thereon and act as guides as described below. 
     A representative latch element for this first embodiment of the present invention is depicted in  FIGS. 7 and 8 . Here, latch element  60  is in the form of a pawl having a base  62  and an elongated arm  64  that terminates in a hook  66 . A pair of oppositely projecting trunnions  68  are cylindrical in configuration and extend oppositely outwardly from base  62 . Arm  64  is provided with a post  65  on one side thereof and an inclined plane  69  forms a cam surface, the purpose of which is described in greater detail below. 
     With reference now to  FIG. 9 , the assembly of base  32  and cover  50  to form housing  31  along with the mounting of a pair of latch elements  60  is shown. As may be seen in  FIG. 9 , when cover  50  is placed on base  32 , blocks  54  will abut blocks  42  with bores  18  being aligned. It may be here noted that blocks  42  may be tiered, for dimensional reasons, if desired. Each of seats  46  are opposed to a respective seat  56  to form a seat pair for mounting trunnions  68  of each latch element  60 . To this end, each of trunnions  68  is received in a respective cylindrical cavity  47 ,  57  so that latch elements  60  may pivot relative to the housing  31 . This mounting is also shown in FIG.  10  and it may be seen that the inclined planes  69  of the pair of latch elements  60  face each other with hook portions  66  also projecting towards one another. By providing the tiering construction of blocks  42  it may be seen that suitable dimensions are provided so that the lower portion of block  42  will not interfere with the pivotal movement of arm  64  of latching element  60 . Also in  FIG. 10 , it may be seen that bolts  16  extend through the housing  31 . Furthermore, it may be seen that the mounting of cover  50  to base  32  forms an entryway  70  into the interior  33  of housing  31  in order to dock the catch piece as described below. 
     The organization of the elements of latching assembly  20  is shown in FIG.  11 . With reference again to  FIG. 3  along with  FIG. 11 , it may be seen that core  22  has a pair of oppositely projecting mounting arms  71  extending from fin  24  and a pair of oppositely projecting mounting arms  73  which project from fin  26 . Seats  72  are provided in each arm  71  and seats  74  are provided in each arm  73 . A pair of transverse ribs  76  are formed on fin  24  and define a channel  77 . Likewise, a pair of parallel ribs  78  are formed on fin  26  and define a channel  79  therebetween. A rod  80  extends between one set of arms  71 ,  73  and another rod  80  extends between the other set of arms  71 ,  73 . 
     With reference now to  FIGS. 11 and 12 , it may be seen that core  22  along with its associated structure may now be referred to as an arming member  23  is mounted in the interior  33  of housing  31  and is held in position and guided by means of posts  48  and  58  ( FIGS. 5 and 6 ) that are respectively received in channels  77  and  79 . Arming member  23  is biased into a first position by means of compression springs  82  that extend between each L-shaped rib  44  and a respective arm  71  wherein each spring  82  is received in seat  72  thereof. With reference to  FIG. 11 , it may be seen that a representative latch element  60  is mounted for rotation between a pair of seats  46  and  56  and is biased into a capture state by means of a compression spring  84 . As will now be described, rods  80  along with compression springs  84  act to move latch elements  60  between the capture and release. 
     With reference, then, to  FIGS. 13 and 14 , it may be seen that, when arming member  23  is in a first position (FIG.  13 ), rods  80  bear against inclined planes  69  to force latch elements  60  apart by rotating them against the force of compression springs  84 . Arming member  23  is biased into this first position by compression springs  82  which have greater spring constants than springs  84 . Accordingly, absent any other forces, arming member will be biased rearwardly into housing  31  and latch elements  60  will be moved into the release state. However, when arming member  23  advances toward the entryway  70 , rods  80  likewise move forwardly. This corresponds to the movement of arming member  23  into a second position. When this occurs, rods  80  move along inclined planes  69  to permit compression springs  84  to move latch elements  60  into the capture state, as shown in FIG.  14 . 
     The operation of electromechanical lock  10  will become more apparent after discussing the structure of catch piece  90  that is best shown in FIG.  15 . Here, catch piece  90  is in the form of a T-shaped block having a base  92  and a top portion  94  from which a pair of lips  96  oppositely project. Lips  96  form shoulders  97  adapted to be engaged by hook portions  66  of latch elements  60 , as described below. Countersunk bores  98  are provided to receive screws  99  for securing catch piece  90  to the second structure portion, such as the door as is shown in FIG.  1 . It should be appreciated that catch piece  96  defines an armature, as is known in the art of electromechanical locks, with catch piece  90  being formed as a suitable ferromagnetic material. By this term, “ferromagnetic” it is meant that the substance will be attracted to a magnetic force. Moreover, the term “lips” as used herein refers to any physical structure that can be positively engaged by the latch element, and may include, without limitation, hooks, prongs, loops, flanges, shoulders, cut-outs, etc. 
     Finally, turning to  FIGS. 16 and 17 , the operation of electromechanical lock  10  should be fully appreciated. In  FIG. 16 , it may be seen that arming member  23  (including core  22 , arms  71 , arms  73  and rods  80 ) is biased by compression springs  82  into a first position such that rods  80  acting on inclined surfaces  69  force latch elements  60  apart and thereby compress springs  84 . In this position, latch elements  60  are in the release state. Catch piece  90  is docked in a received state through entryway  70  so that it is received in the interior of latching assembly  20 . Absent the presence of current running through coil  28 , door  12  can swing away from casing  14  since springs  82  maintain latch elements  60  in the release state. However, as is shown in  FIG. 17 , when an electrical current is present in coil  28 , core  22  and coil  28  act as an electromagnet that magnetically retains catch element  90 . As door  12  is moved, this magnetic attraction causes arming member  23  to move forwardly toward the second position against the force of springs  82  so that rods  80  move forwardly along inclined planes  69 . Thus springs  84  bias latch elements  60  into the capture state. In this state, hook portions  66  of each latch element  60  engage shoulders  97  formed by lips  96  and mechanically constrain further movement of catch piece  90  out of the received state. 
     It should be understood from the foregoing, then, that the strength of the electromagnet need only be sufficient such that the magnetic force, acting in conjunction with the force of compression springs  84  acting along inclined planes  69  against rods  80  overcomes the compression force of springs  82 . With proper selection of the spring constants of springs  82  and  84  along with the dimensioning of inclined plane  69 , all which should be within the skill of the ordinarily skilled mechanical engineer, the force of the electromagnet can be small relative to typical magnetic locks. This eliminates the increasingly large and bulky electromagnets used in existing controlled access magnetic locks. 
     It should be understood that a wide variety of latching elements may be employed with the present invention without departing from the scope thereof. Moreover, a wide variety of arming elements may be used as well as a wide variety of catch pieces. For example, the catch piece could take any shape and have any structure thereon that provides a way of engaging the latch element. For example, as is shown in  FIG. 24 , instead of lips  96  being oppositely projecting wings, the catch piece  103  may be formed as hollow housing  105  with openings  107  in the face. Thus, the margins of the openings provide peripheral “lips”  109  therearound. In this case, the latching element could extend into the interior of the catch piece  103  and engage the peripheral lip  109  of the opening  107 . 
     The catch could also be configured as arching loops or loop portions that are engaged by the latch elements. Thus, for example, as is shown in  FIG. 25 , arcuate loops  106  are mounted on plate  108  that defines a catch piece  104 . Loops  106  provide “lips” to engage the latching element. It should be understood that  FIGS. 24 and 25  and are merely examples of a catch piece and the structure of the same and, as noted above, a wide variety of structures for the catch piece are possible depending upon the structure of the latching assembly. 
     In order to give examples of other latching assemblies, and without in any way intending to limit the various constructions that the ordinarily skilled artisan may develop based on the teachings of this application, alternative structure as shown in  FIGS. 18-23 . A second embodiment of the present invention is shown in  FIGS. 18-20 . Here, latching assembly  120  is shown and mounted in a housing  131 . Arming member  123  is in the form of a plate  124  that supports an electromagnet  125  thereon. Springs  182  interconnect housing  131  and plate  124  is guided in any suitable manner. Plate  124  is provided with a pair of rods  180  that are received in cam slots  169  formed in arm portions  164  of latch elements  160 . This structure eliminates compression springs  84  in the first embodiment. 
     As is shown in  FIGS. 18 and 20 , springs  182  bias arming member  123  into the first position. In this position, rods  180  slide in camming slots  169  to force latch elements  160  into the release state. Absent a magnetic force, catch piece  90  may move into the received state as shown in FIG.  18  and out of the received state as shown in FIG.  20 . However, when a magnetic current is supplied by wires  185  to electromagnet  125 , the magnetic force is sufficient to overcome the force of springs  182 . Thus, as is shown in  FIG. 19 , electromagnet  125  adheres to catch piece  90  with a magnetic force. Thus, as catch piece  90  is attempted to be removed from the received state, rods  180  slide in camming slots  169  positively advancing latch elements  160  into the capture state. In such state, hook portions  166  of latching elements  160  engage lips  96  of catch piece  90 . 
     A third embodiment of the present invention is shown in FIG.  21 . Here, it may be seen that the electromagnet  225  is formed as part of the catch piece  290 . Head portion  294  provides a pair of lips  296 , and it could be understood that catch piece  290  can be formed of a core material for the electromagnetic coils that form electromagnet  225 . In any event, latching assembly  220  includes an arming member  223  that is slideably mounted on posts  228  and biased by springs  282  as shown in FIG.  21 . Latching elements  260  are pivotally mounted at opposite ends of plate  224  on axles  261  and, when contacted by catch piece  290  are held in the release position (shown in  FIG. 21 ) by means of suitable cam surfaces. Coil springs (not shown but similar to those described below in  FIGS. 22 and 23 ) extend around axles  262  to bias latching members  260  into the capture position. However, due to the action of springs  282 , arming member  223  forces cam members  260  into the release position, as described above. When current is applied to electromagnet  225  a magnetic force is added coupling plate  224  and catch piece  290 . Thus, the movement of door  12  away from casing  14  causes plate  224  to overcome the force of springs  282  so that catch latch elements  260  will pivot into the capture position as should now be understood by the ordinarily skilled person having read this disclosure. 
     Finally, turning to  FIGS. 22 and 23 , a fourth embodiment of the present invention is shown. Here, latch assembly  320  is in the form of a plate  24  that is mounted to a first structure  314  by means of a bolt  322  that has a base block  340  received in a cavity  342  formed therein. A spring  382  biases plate  320  into the first position adjacent structure  314 . Catch  390  is mounted to a second structure  312  and comes into abutment with plate  324  when in a received position in latch assembly  320 . Plate  324  has associated therewith an electromagnet  325 , and a pair of latch elements  360  are rotatably journaled on axles  361  and are biased into the capture state by means of coil springs  384 . 
     As is shown in  FIG. 23 , when current is supplied to electromagnet  325 , catch piece  390  is magnetically attracted to plate  324 . Movement of catch piece  390  away from structural piece  314  moves plate  324  away from piece  314  against the force of compression spring  382 . When this occurs, springs  384  act to rotate latch elements  360  into the capture state shown in FIG.  23 . Upon the release of the electromagnetic force, however, the first force provided by spring  382  is sufficient to overcome the force of springs  384  so as to draw plate  324  toward structure  314 . When this occurs, camming surfaces  369  on the perimeter of latch elements  360  act against the surface  315  to rotate latch elements  360  into the release state shown in FIG.  22 . Here, again, the electromagnet could be part of catch piece  390 , and the mount for latch element  360  be a plate attracted to the magnetic as in the embodiment of FIG.  21 . 
     From the foregoing, it should be understood that the present invention includes a method for electromechanically locking first and second structures together so that, when in a second state, they are permitted to move apart from one another and when in a first state are prevented from moving apart from one another. This method includes all of the steps inherent in the structures described above, taken in any suitable operative order. Broadly, however, the general method of the present invention includes the step of mounting a latching means including at least one mechanical latch element on the first structure with this latch element movable between a capture state and a release state. The method includes a step of biasing the latching element into the release state with a first force. The method includes the mounting of a catch means on the second structure. The method for electromechanically locking includes the docking of the catch means and the latch means together in a received state. The method includes the step of electromechanically coupling the latch means and the catch means with an electromagnetic device that is switchable between an “on” condition and an “off” condition. This step is accomplished such that, when the electromagnetic device is in the “on” condition, the electromagnetic device magnetically co-engages the latching means and the catch means with sufficient magnetic force to overcome the first force whereby movement of the catch means away from the received state results in the latching means moving into the capture state. Alternatively, when the electromagnetic device is in the “off” condition, the latching means and the catch means may be disengaged with the latch element remaining in the release state. 
     Accordingly, the present invention has been described with some degree of particularity directed to the exemplary embodiments of the present invention. Modifications or changes may be made to the exemplary embodiments of the present invention without departing from the inventive concepts contained herein.