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RELATED APPLICATIONS 
   The present application claims benefit to provisional U.S. patent application Ser. No. 60/341,407 entitled “Electromechanical Locking Mechanism”, filed Dec. 14, 2001. The entire disclosure of this application No. 60/341,407 is incorporated by reference herein in its entirety for all purposes. 

   BACKGROUND 
   The present invention is intended as an improvement to pop out handle locks used typically in vending machines and utilized to lockingly engage the door to the main chamber of the machine. 
   In a typical application, a pop out handle system, the door contains a lock mechanism, which includes a pop out handle, actuated by an appropriate key which is exposed to the outer portion of the door. The interior portion of the lock mechanism includes a threaded stud, which extends toward the main chamber of the machine and is typically adapted to be screw threaded into a stud receiving fixture, securely mounted to the inside portion of the main chamber. 
   To unlock the pop out handle lock, and operator inserts the proper key into the lock placed inside the pop out handle, which actuates the handle to pop towards the user. The handle is then turned counterclockwise, which unscrews the lock stud from the internal locking fixture. 
   In order to lock the door to the main chamber, the operator reverses the procedure, such that the door is closed and the stud is oriented in linear alignment with the internal locking fixture (which usually contains a threaded nut), then the handle is rotated clockwise, resulting in engaging the stud into the locking fixture. When the thread is fully engaged, the operator depresses the handle into the recess provided by the machine and the depressed position is maintained by the engagement of a locking bolt. 
   The current design requires significant effort and time to be spent by the person who is filling the vending machine (routeman) when the door is being opened and closed. There is no record of who entered the machine and when the machine was entered. The machine is easily compromised by anyone who has duplicated a key, which is an easy task. If it has been determined that a key had been stolen, or duplicated, there is significant effort, time and expense involved in re-keying the lock. 
   SUMMARY OF THE INVENTION 
   The present invention is a motorized lock, mounted to the inside of a vending machine door or the cabinet. It is intended to decrease the amount of time required to lock the machine by providing a motorized draw-in feature which will pull the door tight and lock it. This draw-in feature is completely automatic. Further, the present invention allows for quick entry of the vending machine, which is actuated by the routeman showing an electronic key. The control electronics for the lock are capable of a large number of different keys being used to gain entry to the vending machine, and will remember an “audit trail”. The “audit trail” consists of the key that gained access, the date and the time of access. A significant history can be developed, limited only by the size of the memory chips in the controller. 
   According to the present invention, a gear motor is attached to a slotted link, which pulls a locking hook which hooks a u-bolt, or a headed bolt, which closes the vending machine door. The gear motor is under the control of a microprocessor based circuit which employs three switches for feedback. 
   The operation of the lock is as follows. For purposes of this description, the starting point will be with the locking hook and the door open with the routeman filling the machine. To begin the close cycle, the routeman swings the door such that it is in close proximity to the main chamber of the machine. This action closes a feedback switch, S 3 , which sends a signal to the control circuit which turns the motor on. S 3  is a plunger type switch, located in the main chamber of the machine such that the door plunges the switch when the door closes. The motor is connected to a multifunction cam wheel which, in turn, is connected to a slotted link, which, in turn, is connected to the spring loaded locking hook. The starting of the motor begins to rotate the locking hook. The locking hook “hooks” a u-bolt, or headed bolt, which is attached to the main chamber of the vending machine. The locking hook is shaped such that it draws the u-bolt in as it rotates, bringing the door closer to the main chamber. The locking hook is provided with six teeth which are engaged by a ratchet mechanism as the hook rotates. This continues until the door gasket between the door and the main chamber is compressed, and two additional feedback switches, S 1  and S 2  close. These switches close due to actuation by two cam surfaces on the multi function wheel. In this condition, the machine is completely sealed and locked. The ratchet mechanism is seated behind the last locking hook tooth, which is held solidly in place by a loaded extension spring between the locking hook and the main housing. 
   When the routeman wants to gain access to the inside of the machine, an electronic key is needed. Each electronic key is provided with a unique electronic serial number and a unique password. Each password is unique to each machine, so a plurality of passwords are stored in each key. The routeman places the electronic key on the key reader and it is read by the control circuit. The control circuit then decodes the key number, which is encrypted, and checks it against its internal database. If the key number is in the data base, the control circuit then electronically reads the password assigned to that machine. If the passwords match, the key is deemed valid. The password is then changed for the next access, and the new password is loaded into the key and is remembered in nonvolatile memory in the control circuit. 
   The motor is then turned on, which rotates the multifunction wheel. One of cams on the wheel engage a ratchet release lever, which pushes the ratchet off of the last tooth of the locking hook, causing the locking hook to pop open, as the loaded locking hook extension spring brings the locking hook open. This causes the vending machine door to open slightly. The wheel continues to rotate until feedback switch S 1  opens. In this position, the locking hook is completely free to rotate allowing the routeman to open the vending machine door fully. S 3  opens when the door opens and the motor again begins to rotate the multifunction wheel. The cam surface that was engaging the ratchet release lever travels past the lever, which releases the ratchet. Another cam surface on the multifunction wheel then pushes the ratchet down to engage the first tooth of the locking hook. The wheel continues to rotate until feedback switch S 2  opens. At this time, the ratchet is engaged into the locking hook, such that if the door was closed, the u-bolt, or headed bolt, would hit the locking hook. The link that connects the multifunction wheel to the locking hook is provided with a slot on the wheel end. This slot allows the locking hook to advance before the motor turns on. If the u-bolt, or headed bolt, hits the locking hook it will cause it to rotate slightly, advancing the ratchet to the second tooth. At that time, the follower attached to the wheel travels down the slot in the link. The harder the door was closed, the further the locking hook would rotate, advancing the ratchet further. This feature is very important, since it allows latching of the door without electricity. When the motor turns on (due to S 3  being plunged), the follower, attached to the multifunction wheel, first travels to the end of the slot on the link. The follower then pulls the link, which rotates the locking hook about the locking hook fulcrum to close and seal the door. If power was lost during a vending machine fill operation and the routeman slammed the door shut, the controller would, upon power up, see that S 3  was closed and S 1  and S 2  were both open. This condition would be a vending machine with the door closed and the multifunction wheel in a position where the locking hook was not fully drawn closed. As such, the controller would automatically turn on the motor to advance the wheel until S 1  and S 2  were closed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an upper right perspective of the present invention. 
       FIG. 2  is the left-side view of the lock of FIG.  1 . 
       FIG. 3  is similar to  FIG. 2  except the left mounting plate has been removed. The locking hook is completely open and the ratchet is engaged. 
       FIG. 4  is similar to  FIG. 3  except the u-bolt is pushing the locking hook closed, moving the ratchet. 
       FIG. 5  is similar to  FIG. 3  except the locking hook is fully closed and the ratchet is engaged into the last tooth of the locking hook. 
       FIG. 6  is similar to  FIG. 5  except the ratchet release lever is pushing the ratchet off of the last tooth. 
       FIG. 7  is a functional block diagram of the control system. 
       FIG. 8  is a timing diagram, illustrating the various operating modes of the system. 
       FIG. 9  is a perspective view of a compartment that is a vending machine in which the locking hook is connected to the frame and the compartment member is connected to the door. 
       FIG. 10  is a perspective view of a compartment that is a vending machine in which the locking hook is connected to the door and the compartment member is connected to the frame. 
   

   DETAILED DESCRIPTION 
   Turning first to  FIG. 1 , reference numeral  1  designates the gear motor, which includes a motor  3  and a gear box  2 . The gear motor is coupled, through a linkage mechanism, to drive locking hook  4 , which engages and pulls in u-bolt  35 . 
   This u-bolt  35  could be substituted for a headed bolt and the locking hook  4  could be substituted for a claw shaped device which would grab the headed bolt around the head and pull it in. 
   Turning now to  FIG. 2 , the left side view of the lock is illustrated. The output shaft  2   a  of the gearbox  1  is coupled to multifunction wheel  25  with key  34 . The multifunction wheel  25  rotates, moving motor pull point  8  in a counterclockwise fashion (in this view). As the motor pull point moves, it pulls link  5  by cam follower  8 A sliding up slot  6  which is integral to link  5 . When the end of slot  6  is reached, link  5  begins to move in an upwardly fashion, rotating locking hook  4  about locking hook fulcrum  10 . The locking hook  4  is pulled at locking hook pull point  7  which travels in slot  9 . As the locking hook  4  rotates, it pulls u-bolt (or headed bolt)  35  towards the lock assembly. 
   The gear motor  1  is attached to mounting plate  11  by motor mount screws  13 A,B,C,D. Mounting plate  11  has a corresponding mounting plate (not shown) on the inside of locking hook  4 . The two mounting plates  11  are further held together by assembly screws  12 A,B,D,E. 
   Turning now to  FIG. 3 , the left side view is again illustrated, this time with mounting plate  11  removed. This figure illustrates the inner workings of the feedback switches and the multifunction wheel. The multifunction wheel  25  is composed of feedback switch cam surfaces  23  and  24 . Cam surfaces  23 A,B are integral to cam surface  23 , and cam surfaces  24 A,B are integral to cam surface  24 . As the wheel  25  rotates, it brings ascending cam surfaces  23 A and  24 A into contact with feedback switches  21  and  22  respectively. When this contact is made, the switches are electrically closed. As the wheel  25  continues to rotate, the risen sections of cam surfaces  23  and  24  keep feedback switches  21  and  22  closed until descending cam surfaces  23 B and  24 B release and therefore electrically open the feedback switches. The feedback switches  21  and  22  are provided with rollers to minimize wear. 
   As link  5  pulls on locking hook  4 , causing it to rotate, spring  14  begins to stretch and charge (increasing its potential energy). Locking hook spring  14  is mounted on one end to mounting plate  11  with screw  16 , and on the other end to locking hook  4  with screw  15 . This spring is used with the release operation described in FIG.  6 . 
   Turning now to  FIG. 4  the ratchet action is illustrated. As locking hook  4  rotates, it is engaged by ratchet assembly  37  at teeth  28 , 29 , 30 , 31 , 32 , 33 . These teeth are provided with a ratchet side  28 A,  29 A,  30 A,  31 A,  32 A and  33 A respectively and a locking side  28 B,  29 B,  30 B,  31 B,  32 B, and  33 B respectively. Ratchet assembly  37  is provided with a ratchet side  37 A and a lock side  37 B. The ratchet assembly  37 , rotates within ratchet guide  27 . Ratchet guide  27  is made up of two ratchet edges  27 A and  27 C and two lock edges  27 B and  27 D. Ratchet guide  27  is integral to both sides of mounting plate  11 . 
   Illustrated in  FIG. 4  is tooth  28  ratcheting the ratchet  37 . The ratchet side of tooth  28 ,  28 A, is contacting ratchet assembly  37  its the ratchet surface  37 A. This causes ratchet  37  to rotate freely within the ratchet guide  27  inside openings created by edges  27 A and  27 C. Ratchet  37  is biased in the clockwise direction within ratchet guide  27  by ratchet spring  18 . Ratchet spring  18  is mounted to mount plate  11  by screw assembly  17  and to the ratchet at screw assembly  19 . When the ratchet surface  37 A reaches the end of  28 A it is pulled by ratchet spring  18  to the side of tooth  28 &#39;s locking side  28 B. This occurs due to the end of surface  28 A and charged ratchet spring  18 , pulling ratchet edge  37 A into contact with tooth  29 &#39;s ratchet edge  29 A. This repeats until ratchet edge  37 B is seated behind tooth  33 B, as illustrated in FIG.  5 . 
   Turning to  FIG. 5  the fully locked state, described above, is illustrated. Once the locking hook&#39;s tooth surface  33 B is engaged by ratchet surface  37 B, it is not possible to open the locking hook, due primarily to the multifunction wheel  25  having surface  36  in contact with ratchet  37  (aside from the tooth engagement). This engagement also makes the assembly act like a deadbolt, that is, it is not able to open until the opening formed by cam profiles  36 A and  36 B in the multifunction wheel is in line with the ratchet. 
   Turning now to  FIG. 6 , the opening state is illustrated. As multifunction wheel  25  continues to rotate, an opening in cam surface  36  beginning with descending edge  36 A and ending with ascending edge  36 B allows the ratchet assembly&#39;s surface  37 B to be pushed off of the last tooth surface  33 B. 
   The multifunction wheel  25  is additionally provided with release lever cam surface  26  which incorporates ascending surface  26 A. As wheel  25  rotates, it brings ascending ratchet release cam surface  26 A into contact with ratchet release lever  20  at surface  20 A. When ratchet release cam surface  26 A hits ratchet release lever  20  it causes it to rotate clockwise about screw and bushing assembly  38 . As the release lever  20  rotates, integral surface  20 B pushes on ratchet assembly  37  at ratchet spring holder  19  causing it to move in the upward direction. It is now able to move in this direction because cam surface  36  is now past the descending surface  36 A which allows the ratchet assembly to move up. The ratchet assembly  37  moves up until the end of its ratchet surface  37 B is clear of the last locking tooth  33 B on the locking hook  4 . Now, the locking hook is released and it is able to rotate freely about locking hook fulcrum  10 , and charged spring  18  pulls it in the counterclockwise direction until the latch hook is fully open. 
     FIG. 7  illustrates the block diagram of the electrical system. The power supply  43  can be any conventional supply, for this embodiment it is a 120VAC/24VDC 2 amp supply. The supply  43  powers the microprocessor based control circuit  40 . The control circuit  40  reads the feedback switches  21 , 22 , 41  and the user credential input system  42 . The credential system can be any type of electronic access control credential including RF, IR, Magstripe cards, Smart cards, etc. but for this embodiment it is a Dallas semiconductor I-Button. These keys are provided with internal memory, capable of remembering each vending machine&#39;s encrypted password as well as an encrypted key number. As described earlier, the machine&#39;s password changes each time the key is used. 
   When the microprocessor based control circuit  40  reads an I-button through the user credential input system  42  it first decrypts the serial number of the key. The control circuit then checks the non-volatile memory to see if that key has access to the lock. If that key is in memory, it then reads and decrypts the password from the key. If the password matches the password stored in non volatile memory, corresponding to the key number, then the key is deemed valid. 
   A new password is generated, encrypted and stored in the key and in nonvolatile memory in the control board. 
   At this point, the optional solenoid driven latch  44  is opened. This latch is used in a different area of the door as the present invention to provide a more secure lock. The solenoid plunger is a simple bolt mounted inside a solenoid that engages a hole in the main chamber of the vending machine. The gear motor  3  is then energized to open the lock. Complete electrical details on a lock open and close cycle are described below under FIG.  8 . Finally, the vending machine access is stored in nonvolatile memory. The entire history of accesses can be accessed through the user information output system  45 . This output system could employ another Dallas semiconductor I-button, a laptop computer, a palm pilot etc. This system has the ability to read the prior accesses along with the date and time. 
   Turning now to the timing diagram in FIG.  8 . This diagram illustrates the states of the feedback switches  21 , 22 , 41  and the locking hook  4  with respect to the state of the system electronics and the vending machine. 
   Again, for purposes of this illustration, the starting point will be with the latch and the door open, with the routeman filling the machine, time event  50 . In this state, motor  3  is off, feedback switches  1 , 2 , and  3  ( 21 , 22 , 41 ) are open and the locking hook  4  has the ratchet  37  on tooth  1  ( 28 ). In this state the microprocessor is waiting for the vending machine door to be closed, which will close switch  3  ( 41 ). This event occurs at time  51  at event  56 . When the switch closes, the control circuit turns on the motor  3 , to advance the multifunction wheel  25  which moves link  5 , which rotates locking hook  4  as fully described above. The motor continues to run until the locking hook advances past teeth  2 , 3 , 4 , 5 , and  6  ( 28 , 29 , 30 , 31 , 32 , 33 ) (events  57 A,B,C,D,E) and switches  1  ( 21 ) and  2  ( 22 ) close, events  58 A,  58 B, time  52 . In this state, the vending machine door is fully closed, the door is sealed shut, and the microprocessor is waiting for a user credential to be shown and validated, which occurs at time  53 . After the microprocessor validates the credential, the control circuit  40  again turns on the motor  3 . Very soon after the motor is turned on, the ratchet  37  is pulled off the locking hook  4  and the locking hook  4  is released at event  59 . The motor  3  remains energized until switch  1  ( 21 ) opens, event  60 , time  54 . In this state, the microprocessor is waiting for the vending machine door to be pulled open. The locking hook  4  is completely free, as the ratchet  37  is pulled completely out of the way of all of the hook&#39;s teeth ( 28 , 29 , 30 , 31 , 21 , 33 ). When the door is pulled open, switch  3  ( 41 ) is opened, event  61 , time  55 . At this time, the control circuit  40  turns on the motor  3  which causes surface  36 B to push the ratchet back down onto tooth  1  ( 28 ), event  62 . The motor  3  stays on until switch  2  ( 22 ) opens, event  63 , time  49 . This sequence then repeats itself. 
     FIGS. 9 and 10  show an exemplary embodiment of the electromechanical locking mechanism. In  FIG. 9 , the compartment  75  is a vending machine into which the electromechanical locking mechanism may be incorporated. The compartment  75  includes a frame  76  and a door  77  that is hingedly attached to the frame  76 . The locking hook  4  is attached to the frame  76  and pivots in relation thereto. The compartment member  35  is attached to the door  77 .  FIG. 10  is an alternative arrangement of the electromechanical locking mechanism in which the locking hook  4  is pivotally connected to the door  77  and the compartment member  35  is connected to the frame  76 .

Summary:
A locking mechanism is provided. The locking mechanism includes a mounting plate that carries a locking hook. The locking hook is pivotal with respect to the mounting plate and may be pivoted from an unlocked position to a locked position. A motor is in communication with a locking hook, and is capable of causing the locking hook to be pivoted to the locked position. The locking mechanism may be opened by use of an electronic key, and may contain electronics capable of recording the date and time a particular key was used to open the locking mechanism. Also, the locking mechanism may be capable of being locked without the use of the motor when the motor is disabled due to power disruption or other circumstances.