Abstract:
A medical cart is provided with a keyless locking system for drawers containing narcotics and for other drawers containing pharmaceuticals. Some personnel may be authorized with codes to open both the narcotics and pharmaceutical drawers while other personnel may have codes that open the pharmaceutical drawers but do not open the narcotics drawers. Preferably, an audit trail is provided to know who had or tried to access the drawers and when the access was attempted and accomplished. To this end there is a memory store and read-out port that allows downloading or read-out of the audit trail. The medical cart has a simplified locking system with fewer and more reliable components comprising cam operated locking bars that operate locking rods that latch with latch portions on the slidable drawers in the cart. The drawers may be automatically locked upon slamming them to a closed position. Preferably, an associated timer causes an automatic relocking operation or a lock switch may be operated to set the locking mechanism to lock the drawer when it is pushed into its closed position. Also, a light source may be provided to illuminate the control panel and drawers. A motion sensor may switch the light off when the cart is put in motion. A light level sensor may sense the ambient light level and switch the light on when the cart enters a darkened room. A mechanical override may be provided to allow access to the contents in the drawers in the event of electronic failure.

Description:
[0001]    This application claims the benefit of Provisional Application No. 60/286,463, filed Apr. 25, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to a medical cart having lockable bins or drawers for holding pharmaceuticals and narcotics.  
         BACKGROUND OF THE INVENTION  
         [0003]    Currently, in hospitals or other medical facilities medical carts mounted on wheels are positioned where needed and have an electronic keypad or other kind of electronic operated device that is operated by medical personnel to unlock the bins or drawers on the cart to allow access to the contents. Often, it is desired to have narcotics on the medical cart and these narcotics are kept in a separate narcotics drawer from the pharmaceuticals that are kept in other drawers. Heretofore, such narcotic drawers were locked mechanically as with a key lock. While there are medical carts in use with an electronic keypad, they unlock the narcotics drawer with the other drawers. There may be instances, where it is desirable that only certain authorized personnel are allowed access to prescription drugs in the pharmaceutical drawers but they are not authorized to access the narcotics in the narcotics drawer. Thus, there is a need for a medical cart that has a separate electronic locking of the narcotics and the pharmaceutical drawers to allow access to the narcotics only by persons specifically authorized to dispense narcotics.  
           [0004]    Heretofore, the medical carts have had relatively complicated locking mechanisms with many parts which often required maintenance to keep them operating correctly. Also, the locking mechanisms were relatively expensive because of their complexity. Thus, there is a need for a new simplified and less expensive locking system.  
           [0005]    In handling medications, there is often a need, particularly for access to and dispensing of narcotics, that there be an audit trail to allow managers to know who has accessed the narcotics and on what date and time. Current medical carts lack any audit trail capability and hence there is a need for providing such on a medical cart.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, there is provided a new and improved medical cart, as contrasted with the prior art, having a separate electronically operated locking device for the narcotics drawer. Thus, the pharmaceutical drawers may be opened by personnel for accessing the drugs therein; but these personnel may not have authority to access the narcotics so the narcotics drawer will remain locked even though the pharmaceutical drawers are unlocked. On the other hand, certain medical personnel may be authorized to dispense both pharmaceuticals and narcotics and may want to open both kinds of drawers and such persons are provided access upon a proper input of a code on a control panel for the narcotics. The preferred invention provides a keyless unlocking of the non-narcotic medication containing drawers and a keyless unlocking of the narcotic containing drawer.  
           [0007]    Particularly, with narcotics or other medications, management may want to have audit trail to know who had access to the narcotics and when. In accordance with another important aspect of the invention, there is provided an entry log stored to identify persons accessing or trying to access the drawers in the cart. More specifically, each person may have an identifying code, e.g., a pin number; and a memory store in the cart is associated with the computer stores the person&#39;s identity code, the date, and time of access to the narcotics for a later read-out. In the preferred embodiment of the invention, the cart has a read-out or downloading port that connects to the memory store and allows read-out of the person, the date and time of access to the narcotics drawer and/or other medication drawers to provide the desired audit trail. The read-out information may be sent to a printer or downloaded into a notebook computer. The pre-programmed code inputted by the person preferably identifies the person such as by a pin number as well as causes an unlocking operation of the drawers when a proper preprogrammed code is inputted. The computer system stores the identify of the proper coded input, the date and the time for each access to medications an/or narcotics and thereby provides an audit printout capability of the date, time and operator codes whenever the cart is unlocked and/or locked.  
           [0008]    In accordance with an important aspect of the invention, the medical cart is provided with a simplified locking system as contrasted to the locking system used heretofore in medical carts, in that it has fewer operating components and is reliable in operation thereby lessening the need for maintenance and/or repair. In the preferred embodiment, this is achieved by the use of cam operated lock bars that operate locking rods that latch with latches on the slidable drawers. Preferably, the latch bars are operated by cams mounted on a shaft which may be turned to lift the latch bars and unlock the latch bars. The cams may be mounted on a shaft turned by an electric motor which is operated by the controller or computer system, which includes a central processor unit (CPU). This preferred locking mechanism may also be manually operated as by use of a key, in a mechanical only version of the medical cart. The narcotics drawer may be double-locked if desired to provide added security. Also, if the power fails, a mechanical turning of the shaft may be used to open the drawers.  
           [0009]    In accordance with a further aspect of the invention, the drawers and bins are adapted to be slammed shut and automatically relocked. Preferably, the electronic operator or controller has an associated timer or timing device that, upon expiration of a set of predetermined time interval, causes an automatic relocking operation shifting of the locking devices to the locking position locking all of the drawers that are closed. If a drawer is left open, usually inadvertently after the timer has timed out, the drawer need merely be pushed closed with a good force to cause it to be automatically slam locked. In the illustrated embodiment of the invention, the locking devices includes a pair of cooperating locking elements one of which has a camming portion preferably in the shape of a wedge to shift relative to a locking rod to lock the drawer when it is slammed shut. Herein, the power for the electronic devices and motors is from a rechargeable battery carried on the cart.  
           [0010]    A still further locking operation may be provided in that a manually operated switch, such as a “lock” push button may be provided such that operation of the lock push button results in an automatic locking of the closed drawers. That is, after pushing of the lock switch those drawers that are in the closed position will be locked and those drawers still open and then slid to the closed position will also be automatically relocked.  
           [0011]    In accordance with an important aspect of the invention, the medical cart is provided with a light source that illuminates the control panel and the bins to allow identification of and removal of the medicine from a bin in a darkened hospital room. Preferably, the light also illuminates the area around the cart to assist in shifting of the cart&#39;s position and travel. Thus, the patient need not be awakened by turning on the room light in order to use or move the cart. Preferably, the light source is also controlled automatically by sensors such as a motion sensor that detects movement of the cart and automatically switches on the light when the cart is put in motion and the light switch is positioned for automatic control. Another sensor may be a light level sensor that senses the ambient light level and switches the light source on when entering a dark room and switches the light source off when moving into an ambient bright light area.  
           [0012]    In the preferred embodiment of the invention, the medical cart has a keypad and associated computer or controller in the form of electronic operator and also may have a removable cassette that has rows of small bins or drawers therein. The narcotics drawer is separate from the cassette. The preferred locking devices include a driven cam shaft capable of driving a locking bar in opposite directions in order to either lock or unlock the drawers. In the illustrated embodiment of the invention, an electric motor drive is used to turn the cam shaft to operate a latch lifter which shifts a locking rod upwardly from holding and restraining engagement with a wedge-shaped cooperating, latch element to release the bins in the cassettes for being pulled open. In this embodiment, the proper operational sequence of keys on the keypad is made to cause the computer to operate the motor driven cam shaft to shift both locking bars to unlock the narcotics drawer and the medication drawer.  
           [0013]    In the preferred embodiment of the invention, one input code is inputted by persons to access the pharmaceutical drawers only. A second input code, in addition to the first input code, must be inputted to allow access to the narcotic drawer. Herein, the narcotic drawer is locked by two locking bars and the first coded input causes the electronic operator to shift the pharmaceutical, associated lock bar to an unlocking position and then the second input code causes the electronic operator to shift the narcotics, associated lock bar to the unlocking position thereby allowing access to the narcotics drawer.  
           [0014]    In the preferred embodiment of the invention, it is preferred to provide a mechanical override that allows access to the slidable drawers in the event of an electronic failure or for some other reason. The preferred mechanical override comprises a key operated kind of lock override that must be unlocked by a mechanical key. Herein, the key not only does the unlocking but also may be used to shift the locking bars to the unlocking position. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    [0015]FIG. 1 is a perspective view of a medical cart having electronic locking of the narcotic and non-narcotic bins or drawers;  
         [0016]    [0016]FIG. 2 is a rear view showing internally within the medical cart the locking mechanisms driven by twin motors operated by the keypad electronic operator to unlock or lock separately the narcotics and non-narcotic drawers;  
         [0017]    [0017]FIG. 3 is a rear view of a cassette having two rows of non-narcotic bins showing the cooperating locking elements in the form of rods and wedge-shaped blocks;  
         [0018]    [0018]FIG. 4 is a front view of the cassette of FIG. 3;  
         [0019]    [0019]FIG. 5 is a perspective view of another embodiment of the invention having cassettes that extend the width of the medical cart;  
         [0020]    [0020]FIG. 6 is a perspective view of another embodiment of the invention which is shorter in width than the embodiment of FIGS. 1 and 5;  
         [0021]    [0021]FIG. 7 is a perspective view of a medical cart which is similar to that illustrated in FIG. 6, but which is wider than the medical cart shown in FIG. 6;  
         [0022]    [0022]FIG. 8 is a rear view similar to that of FIG. 2 showing the locking mechanism, the CPU module, and a mechanical override;  
         [0023]    [0023]FIG. 9 is a rear view similar to FIG. 3 of a cassette;  
         [0024]    [0024]FIG. 10 is an enlarged view of the control panel including the keypad for the medical cart;  
         [0025]    [0025]FIG. 11 is a rear perspective view of a cam shaft module and an electrical module used in the preferred embodiment of the invention; and  
         [0026]    [0026]FIG. 12 is a block diagram of the apparatus in the medical cart.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]    As shown in the drawings for purposes of illustration, the invention is embodied in a medical cart  10  having a main body or housing  12  which is preferably mounted on wheels or rollers  14  for assisting in moving the cart from one location to another. The cart housing  12  has an upper or top wall  16  on which is mounted an electronic operator  20  comprising an electrical control panel  21  having a keypad  22  having keys for operating an internal locking system. The cart also has a vertical housing side walls  30  attached to a front wall  31  and to a back wall. A sliding tray  26  may be slid into and from the housing and includes an outer handle  28  pushing the tray inward or pulling outward of the housing. The front housing wall  31  has an open front face providing access to drawers and bins.  
         [0028]    In the illustrated medical cart there is a narcotics drawer  32  (FIGS. 1 and 2) that is slidably mounted by slides on side walls  34 . The narcotic drawer has a front panel  36  with a handle  38  and a bottom panel  39 . A rear vertical panel  37  cooperates with a locking device to lock the slidable narcotics drawer in its closed position, as illustrated in FIG. 1, in which the previously opened top of the drawer is covered by the upper part of the cart. The slidable drawer  32  may be pulled outwardly from the cart when in its unlocked position or condition.  
         [0029]    Also, the medical cart contains non-narcotic drawers or bins  40  that are slidable between closed positions and open positions such as shown in FIG. 4. The non-narcotic drawers or bins  40  usually contain prescription drugs, pharmaceuticals or the like and the bins  40  are also kept locked in the closed position until the locking mechanism is operated by the electronic operator  20 . Preferably, the bins  40  are small slidable bins in double rows  44  and  46  in a cassette  48  that has sidewalls  49 , a bottom wall  53  and a top wall  50 . The cassette also has a front wall  51  with the bins  44  and  46  slidable between the open and closed positions in openings in the cassette front wall  51 . Herein, two cassettes  48  are mounted and vertically spaced in the medical cart shown in FIG. 1 to provide four rows of bins with five bins in each row.  
         [0030]    In addition to the above-described drawers, there may be slidable drawers  60 - 65  (FIG. 1) provided on the medical cart that are also lockable or left unlocked, as may be desired.  
         [0031]    The illustrated locking mechanism preferably comprises a motor drive  70  and at least one locking bar  72  that is operated by a rear directional motor drive to shift the cooperable members  74  and  76  relative to each other and from a locking position to an unlocking position with respect to each other. The actual locking mechanism may take different forms but herein it comprises a wedge-shaped block  78  fastened to each a back panel  80  of each slidable bins  40  and a common horizontal locking rod  75  cooperable with the wedge-shaped blocks. Herein, the first locking member  74  has a locking portion in the form of an open groove or slot  82  which receives a locking cylindrical rod portion  84  of the locking rod  75  that is sized to fit in the groove  82 . The grooves  82  open upwardly in the wedge-shaped blocks and a common horizontal rod  75  fits in the grooves  82  of each of the blocks  78  in the row; and thus serves to extend across all of the wedge-shaped blocks to simultaneously lock all of the bins in a row. There is a horizontal rod  75  for each of the rows of the bins.  
         [0032]    The illustrated second cooperable locking member  76  comprises the rod  75  and integral side arms  86  (FIG. 2) at opposite ends of the horizontal rod with each side arm extending forwardly along and inside of the side walls  23  of the cart housing. The side arms  86  extend to outwardly bent ends  86   a  that are pivoted or rotated within holes in the opposite, vertical side walls  23 .  
         [0033]    The rear wall of the cassette comprises an encircling outer strip  89  (FIG. 2) having four joined strip portions  89   a ,  89   b ,  89   c  and  89   d . Mounted at the rear of the cassette adjacent the encircling outer strip  89  are four vertical bin stops  90  that are spaced from one another and extend vertically between the cassette top wall  50  and a central wall  52  extending horizontally and parallel to the tope cassette wall  50 . Four similar bin stops extend vertically between the central wall  52  and bottom wall  53  of the cassette. The bin stops stop the rearward travel of the bins and when the bins are pushed against the bin stops the grooves  82  in the blocks  74  are aligned with one another and with the rod  75  to receive it to lock the bins  40  in their closed and locked position.  
         [0034]    The locking devices also include one or more vertical lock bars  72  and  73  that are guided for vertical sliding movement in the medical cart. Vertically spaced lifters or lifter pins  72   a  and  72   b  (FIG. 2) project normal to the bars to extend horizontally to have ends located beneath the horizontal locking rods such that as the lock bars may be lifted upwardly. The lifters  72   a  and  72   b  engage and lift the locking rods  75  upwardly from the grooves  82  on the bins as the pivotal locking member  76  has its ends  86   a  turn in holes in the housing side walls  23 .  
         [0035]    The electronic operator  20  includes a computer or controller  99  (FIG. 12) connected to and operable by the keypad  22  to energize and control the direction of the rotation of a pair of twin electric motors  100  and  102  (FIG. 2) that drive the locking bars up to unlock and down to allow locking. The narcotics drawer  32  is locked by a dual lock device  104  comprising a pair of horizontal lock members  105 ,  106  removable vertically in vertical slots  107 . The inner ends of the lock member  105 ,  106  may be hooked to the rear wall  37  of the narcotics drawer to hold it in the closed and locked position. The outer rear ends of the lock member  105  and  106  each have a slot  108  with a horizontal bar  109  inserted in the slots  107  in the lock members  105  and  106 .  
         [0036]    In order to open the narcotics drawers  32  the electronic keypad  22  is operated by punching a sequence of keys  24  on the keypad. The keypad just be operated by a proper sequence to cause the computer to operate both motors  100  and  102  simultaneously to operate the dual locking device  104  to move both the lock members up to the unlocking position to allow the narcotics drawer to be pulled outwardly to an open position allowing access to the narcotics in the drawer. The computer is programmable by the hospital or others to recognize a code or codes to provide access to a medication drawer and a code such as a pin code to identify the person. The computer is also programmed to recognize the code or codes to allow access to the narcotics drawer. The computer is also programmed to log the date, time, and operator codes each time the keypad is operated. On the other hand, when operating the keypad  22  with a certain sequence to open the non-narcotic bins  44 ,  46  for removal of prescription drugs or the like, only one motor  102  is operated to raise the vertical lock bar  72  to pivot the horizontal locking rod  75  upwardly from the grooves  82  in the wedge-shaped locking members  74  in each row of bins  40 . But lifting one of the locking bars is insufficient to unlock the narcotics drawer. Thus, all of the bins in a row are simultaneously unlocked and can be pulled outwardly to dispense the contents in the respective bins.  
         [0037]    In the preferred embodiment of the invention, a timing device or timer  98  (FIG. 12) is associated with the electronic operator&#39;s computer  99  and upon elapsed of a predetermined period of time, the electric motors  100  and  102  are caused to be energized by the computer to lower the lock bars  72  or  73  and their lifters  72   a  and  72   b  to allow the horizontal rods  75  to drop into the grooves  82  in the wedge-shaped blocks  78  on the ends of the non-narcotic bins  44  and  46 .  
         [0038]    If bins are left open and the predetermined period of time has elapsed and the locking rods  75  have positioned to lock the closed bins and other bins are still in the open position, such as two lower bins  46   a  and  46   b  (FIGS. 3 and 4), these unlocked bins  46   a  and  46   b  may be slammed to the closed position against bin stops  90  with their grooves  82  aligned to receive the horizontal rod  75 . As the wedge-shaped blocks  74  move rearwardly to engage the horizontal rod  75 , inclined cam surfaces  110  on the blocks slide under the rod and pivot it upwardly about the pivot ends  86   a  allowing the block and drawer go continue to slide rearwardly until the grooves  82  in the blocks are aligned with the rod allowing it to drop down into the grooves  82 . Thus the drawers may be slammed shut and locked.  
         [0039]    In FIG. 7, there is illustrated a narrow width medical cart  10   a  having an upper narcotics drawer  32   a  and two cassettes having bins  48   a . The drawer  32   a  and cassettes extend the width of the cart housing  12   a . An electronic operator  20   a  in the forms of a keypad  22   a  operates the locking system which may be the same as that described heretofore and hence need not be repeated.  
         [0040]    In FIG. 6, the cart lob has an upper narcotics drawer  32   b  and a pair of non-cassette, pharmaceutical bins or drawers  48   b . An electronic operator  20   b  having a keypad  22   b  and a controller or computer controls the locking system that may be the same as described above to allow unlocking of the narcotics drawer separately from the unlocking of the pharmaceutical drawers. In FIG. 7, the medical cart 10c is similar to the cart lob of FIG. 6; but it is wider in width.  
         [0041]    It is preferred that the user of the medical cart have a simple manner of relocking the drawers after having opened one or more of the drawers and removed pharmaceuticals and/or narcotics from the opened drawers. To this end, there is provided a lock operator  103  preferably in the form of a “lock” operator such as a “lock” push button  104  that operates a switch connected to the CPU to cause the locking operation by operating the electric drive for the locking devices. The above-described timed out locking operation is a fail safe in the event that if the user does not push the push button  104  after accessing a slidable drawer, and closes the drawer, the drawer will later be automatically locked when the timer times out upon expiration of the time period, the CPU causes operation of the motor to shift the lock bars and lock rods to the lock position. Herein, the control panel  21 , in accordance with the invention, comprises the key pad  22  having numbered push buttons  102  that must be pushed with the proper pre-programmed code to send the proper signals to the computer  99  to cause it to unlock the slidable drawers. The control panel  21  also includes a lock operator preferably in the form of a push button  104  that upon operation sends a signal to the CPU that causes the computer  99  to initiate the locking operation by activating the electric motor that shifts the lock bars to their locked position. Those slidable drawers in their closed position are locked immediately and those in the open position will be locked when they are slid to the closed position.  
         [0042]    Herein, the electrical power source may include a battery  109  (FIG. 12) and there is provided a low battery light  108  on the control panel to indicate when the battery power is low.  
         [0043]    Preferably, there is also provided an audit port  110  whereby the computer  99  may be accessed to determine who, when, and how often the proper preprogrammed codes were used, particularly to gain access to the narcotics drawer. A suitable read out device is connected to the audit port  110  to interrogate the computer. Particularly with narcotics or other medications, management may want to have audit trails to know who had access to the narcotics and when. In accordance with another important aspect of the invention, each person may have an identifying code and the memory store  114  (FIG. 12) may store the personalized identity code, the date, and time of the person&#39;s access to the narcotics bin for later read-out. In the preferred embodiment of the invention, there is a readout, audit port  110  on the control panel  21  that connects to the memory store  114  and the computer and allows readout of the person, the date and time of access to the narcotics drawer and/or other medication drawers to provide the desired audit trail. The pre-programmed code inputted by the person preferably identifies the person as well as causes an unlocking operation of the drawers when a proper pre-programmed code is inputted. The computer causes entry into the memory data for storing the identity of the bin accessor, the date and the time for each access to medications an/or narcotics.  
         [0044]    In accordance with an important aspect of the invention, the medical cart is provided with a light source  120  that illuminates the control panel  21  and medication and narcotic bins to allow identification and removal of the medicine in a darkened hospital room. Thus, the patient need not be awakened by turning on the room light. Preferably, the light source is also controlled automatically by sensor  122  such as a motion sensor  122   a  that detects movement of the cart and automatically switches on the light when the cart is put in motion and when the light switch  124  is positioned for automatic control. Another sensor may be a light level sensor  122   b  such as a photo cell device that senses the ambient light level and switches the light source on when entering a dark room and switches the light source off when moving into an ambient bright light area. The light level sensor may be an optical cell that is located on the control panel  21 , as best seen in FIG. 10.  
         [0045]    As best seen in FIG. 10, there is a task light switch  124  that is movable among an upper “on” switch position in which the light  120  is lit and a lower “off” position where the light is “off.” A third intermediate central position is labeled “auto”; and when the switch  124  is in the “auto” position, the light is under control of the sensors  122   a  or  122   b.    
         [0046]    The control panel  21  also has a low battery light  126  that is lit when the battery is low. The battery is carried on the cart and the housing has an access port for allowing connection of the battery to a battery charger when the light  126  is lit.  
         [0047]    A beeper push button  128  may be pushed to cause a beep to be signaled each time a push button is operated to operate a switch associated therewith. The beeper provides an audio signal to the user that the push button has been pushed sufficiently to operate an associated switch so that the code will be entered properly. Lack of a beep means that a numerical push button switch was not operated sufficiently to enter that numeral into the CPU. A “beep on” light is lit when the beeper push button has been operated to activate the beeper. If the beeper push button is not pushed, the beeper light  129  remains unlit and there is no sound when a numeral push button is pushed.  
         [0048]    In the preferred use of the control panel  21 , the operator is provided with the operator&#39;s identity code, e.g., numerals 5 and 6 and with a code for entry into a medical drawer, e.g.,  829 . The operator can gain access to the medication drawers by first depressing a medication push button  132  on the control panel and then pressing the pre-programmed code 5, 6, 8, 2, 9 push buttons in that order. This inputted code is also recorded in the memory store and is recognized by the CPU operated motorized locking system to unlatch the medication drawers only. To gain access to the narcotics drawer, the operator not only presses the above-described codes above for turning the cam shaft through  135 ° but also depress a “NARC” button  133  followed by another preprogrammed narcotic code, e.g., 2, 6, 9, 1. Operation of the push buttons “2”, “6”, “9” and “1”, in that sequence causes the CPU to recognize a proper code for narcotics dispensing and to cause the motor to turn the cam shaft another  135 ° for a total of  270 ° that lifts both latch lifters thereby unlocking the narcotics drawer. Thus, it will be seen that operator has operated the “med” push button, numerals 5, 6, 8, 2 and 9 push buttons, the “narc” push button, numerals 2, 6, 9, 1 push buttons to unlatch the narcotics drawer in this example. Manifestly the codes may be different for different people or the same code with each person having a pin number that identifies the person unlocking the drawers and the manner of coding may differ substantially from that described herein, which is only one of the many kinds of coding operations that could be used and all within the purview of this invention.  
         [0049]    In the embodiment of the invention shown in FIG. 8, the locking mechanism  150  comprises electric drive in the form of an electric motor  151  connected to an end of a horizontally extending cam shaft  152  having a series of cams  153  thereon for moving the locking bars  72  and  73  that in turn operates locking rods  75  to unlatch the bins or drawers  40 . The electric drive could be other forms than an electric motor such as electrically operated solenoids or the like. More specifically, the electric motor  151  turns the cam shaft  152  to turn through a predetermined amount, e.g.,  135 ° causes the cams to push upwardly rearwardly extending cam follower projections  155  on the lock bars  72  and  73  thereby raising upwardly the lock bars to their unlocking position at which forward latch lifting projections or pins  72   a ,  73   a  located underneath the lock rods  75  push the lock rods  75  upwardly to rotate about pivot ends  86   a  in sidewalls  40  of the cassettes  48 . As the locking rods pivot upwardly, their latching rod portions  84  raise from latching engagement in the slots  82  in the wedge-shaped latch members or blocks  78  projecting rearwardly from the slidable bins  40 . So long as the lock bars  72  and  73  remain raised and the locking rods  75  are pivoted upwardly to the unlatching position, the medication bins  40  may be slid to the open position to provide access to the medications in the respective bins  40 .  
         [0050]    Upon depression of the lock bar push button  104 , the CPU causes the motor drive  70  to reverse rotation of the cam shaft  152  through the same increment, e.g.,  135 ° whereby the spirally-shaped cams turn and the cam follower projections  155  on the lock bars  72  and  73  are lowered to their stop position shown in FIG. 8 where the rearward end of the cam follower projection  155  abuts a vertical shoulder  158  at the end of the spirally-shaped cam. The lock bars may be biased downwardly, as by springs (not shown), and the locking rods  75  may also be spring biased to turn down about their pivot ends  86   a  to assure the travel downwardly with the lifter pins  72   a  and  73   a  against which they rest and thereby lower their latch rod portions  84  into aligned slots  82  on the latch members  78  for those bins in the closed positions. In the lock closed position, the bin&#39;s latch block has its slot  82  aligned to and receives therein a rod portion  84  of the locking rod  75 . If someone tries to pull on the outer handle of a locked bin  40 , the latch member  84  of the bin is held by its engaged rod portion against sliding forwardly.  
         [0051]    As explained above, the wedge-shaped surface on the latch member  84  allows a bin to be shoved to its closed lock position, at any time, that the locking rod  75  is lowered into the locking position.  
         [0052]    The illustrated locking system is formed with easily replaceable modules or units for replacement if a unit should fail. For example, the CPU, motor and battery (not shown) are mounted in a module  174  that is mounted in the housing by horizontal mounting brackets  175  in the form of horizontally extending flanges  175  that are secured by mechanical fasteners at hole locations  175   a  in the flanges. Likewise, the cam shaft and cams  153  are in a module having vertical end walls  176  and a front wall  177  that is secured by fasteners to the housing. This electrical module can be easily replaced if there is a problem with the cams or cam shaft. Also, the lock bars  72  and  73  can be easily replaced. The cam shaft, lock bars, and pivoted locking rods result in an inexpensive and simple locking system that is also a relatively low maintenance item.  
         [0053]    In some instances if there is a power failure, it may be desired to have a mechanical access to the medications including narcotics in the bins because the keypad or, the CPU are not working or for whatever reason. Herein, there is a mechanical override system  180  that includes a key operated lock  181  have a key slot  181   a  to receive a key. The key lock is connected at its inner end to a cam shaft  183  parallel to the motor driven cam shaft  152 . This override cam shaft has spirally-shaped cams  184  thereon similar to the cams  153  on the motorized cam shaft. The cam shaft  183  has spirally-shaped cams  184  thereon similar to the cams  153  on the motorized cam shaft  152 . The cams  183  have spirally-shaped, outer cam surfaces bearing on the underside of rearwardly extending, cam follower projections  185  on the locking bars  72  and  73 . The override cam follower projections  185  are located above the cam follower projections  155  that are lifted by the motor driven cams  153 . The turning of the override shaft  183  through  135 ° causes the same lifting of the locking bars  72 ,  73  as done by a  135 ° rotation of the motor driven cam shaft  152  to unlatch the bins for removal. A rotation of the override cam shaft  183  through  270 ° by the key lock unlocks the narcotics bin. Thus, it will be seen that a mechanical system may be provided to operate the locking mechanism. If a less expensive, all mechanical system is desired, then the CPU, battery and electric motor need not be provided and the motor driven, cam shaft  152  and its cams  153  may also be eliminated.