Abstract:
A modular drawer system provides a system of interchangeable components that are easy to assemble. The system requires few fasteners because most of the parts are slidably interconnected. Many parts perform dual functions. A removable lock tray and a tracking mechanism to provide easier steering of a rolling cart are provided. A lock bar assembly with few moving parts is easily assembled. In addition, an accessory track provides two types of attachments for accessories, a more flexible, snap-on attachment and a more permanent, bolted attachment.

Description:
This application is a continuation of application Ser. No. 08/743,619, filed Nov. 4, 1996. 

   BACKGROUND OF THE INVENTION 
   This invention pertains to a modular drawer system with components that are slidably connected. More particularly, it pertains to a modular rolling cart. Even more particularly, it pertains to a modular cart that can be used to dispense medication. 
   In settings where it is necessary to dispense medication to a large number of individuals in an efficient manner, such as a nursing home or a hospital, drawer systems containing a plurality of drawers and/or cassettes are often utilized. Typically, these drawer systems are supported on wheels to provide a rolling medication cart. A cassette is defined as a transportable storage device that may slide into a cart much as a drawer does. The purpose of the cassette is to provide a means of exchanging empty medication containers with ones that have been refilled. The cassette may comprise a plurality of drawers, trays or bins for organizing medications. Typically, when a cassette is inserted into the cart, the cassette drawers are locked by the same locking mechanism that locks the other drawers. In addition, the cassette may have a separate locking system so that the cassette drawers can be locked when the cassette is removed from the cart. Cassettes are often received by nursing homes with a selection of medication. When that medication has been used, the entire cassette is removed from the cart and returned to the pharmacy for replacement. A second cassette is inserted in its place. 
   These drawer systems typically contain drawers for the medications as well as patient records and other information necessary to the health care professional administering the medication. In addition, it is preferable that these carts act as mobile work stations, so that they provide a surface for writing and recording information, means for maintaining orderly patient charts, means for dispensing supplies and other consumables, and that they include disposal means for trash and for used sharps, such as needles. 
   Depending on the circumstances of use of such a cart, many different styles may be appropriate. Some applications require a cart with fewer, deeper drawers, while other applications require a cart with numerous, more shallow drawers. In addition, it may be desirable to include some drawers that provide additional locking capability because they may contain narcotics or other controlled substances. Cart size is also a factor. Depending on the space available in the hospital or nursing home hallways, a smaller or larger cart may be desired. 
   From a manufacturer&#39;s perspective, it is desirable to have as much uniformity among product lines as possible. It would be preferable to have common parts that can be used to build a multitude of carts which are customized to meet each individual customer&#39;s requirement by offering different sizes, shapes, and numbers of drawers. Furthermore, it may be desirable to have accessories such as sharps disposal containers, waste containers, additional work or writing surface space, lighting, and a chart storage area. 
   Medication carts are often used in nursing homes. The hallways in nursing homes are often carpeted, therefore, the wheels on a cart must be able to roll freely and steer easily on such carpeted floors, as well as on tiled floors. Furthermore, the cart needs to be able to be steered in a relatively small turning radius by one individual with a minimal amount of effort. The cart must also be stable, it should not easily topple over. 
   As previously noted, some of the medications contained within the cart may be controlled substances and so require an extra level of security. To prevent unauthorized access to any of the materials contained within the cart, it is desirable that the entire cart be able to be locked at any time when the individual responsible for the cart is away from it. Preferably, it includes a mechanism that allows any open drawer to be closed, but not reopened, while the lock is activated. More preferably, it allows for a drawer to be locked in more than one position so that if a drawer is partially closed it cannot be pulled open, but is locked in that partially closed position to minimize access to its contents. This locking mechanism can include a key lock. The lock mechanism may also be electronic so that it can be activated remotely. 
   It is desirable to have a simple, easily fabricated lock bar assembly to lock the drawer system with as few components as possible. Prior art systems, such as those disclosed in U.S. Pat. No. 4,822,116, Relyea et al, issued Apr. 18, 1989, provided a lock bar assembly comprising an extrusion that housed a lock tab, a spring and a pin for each drawer that was to be locked. The entire column, including the extrusion, moved up and down to lock and unlock the drawers. The locking tabs in that configuration moved vertically to engage a notch in the drawer slide and lock the drawer. It is more desirable to have a single, one piece locking tab for each drawer plane per cart side that moves within a stationary extruded column. A drawer plane is defined as a horizontal plane defined by the drawer guides in which one or more drawer slide can be located. If there are two drawer bays on a side, or if the drawer system has drawers on both sides, then there will be the possibility for two, or more, drawer slides to be in one drawer plane. Such a configuration is simpler, less expensive to make and takes less time to assemble into a lock bar assembly. 
   The locking mechanism needs to be durable. A drawer system of this type is often locked and unlocked many times a day. Each time a medication is removed and the operator walks away from the cart, the cart should typically be locked. To administer the next medication, the operator must unlock the cart, take out the medication and then relock the cart. Depending on the application, the lock may need to withstand hundreds of lockings and unlockings every day. It should provide years of reliable service. It is preferable that the locking mechanism be easily replaceable, if that should become necessary. For example, if a key were lost, the locking mechanism could be changed so that the previous key no longer unlocks the cart. A replaceable locking mechanism also provides manufacturing ease and the ability to replace or repair damaged locks readily. It is more preferable that the locking mechanism be a modular, replaceable article. 
   Assembling customized carts can be a time-consuming and expensive process. To make the carts more cost efficient, and therefore more attractive to the customers, it is preferable that a customized cart be able to be assembled with the fewest number of fasteners in the least amount of time. It is more preferable that components lock together or slidably interconnect, rather than using numerous fasteners such as screws or rivets. Furthermore, to minimize assembly time, the number of parts per drawer system, and the overall system cost, it is preferable that individual components be designed to perform more than one function. 
   The drawers in such a cart preferably encourage an operator to pull them open from the middle of the drawer. It encourages proper drawer opening and prevents a drawer from binding or seizing up as it might if it were pulled from the side at an angle. 
   Depending on the needs of a customer, the cart configuration may provide access to drawers on one side or both sides of the cart. Preferably the two sides can be locked and unlocked separately so that one side can be accessed while the other side is securely locked. 
   Preferably the carts can be refurbished quickly and inexpensively. They should be manufactured with easily replaceable parts that will allow for a new appearance without requiring replacement of all or most of the parts, particularly replacement of the more expensive parts. They should also be able to be reconfigured so that a customer who previously desired one drawer configuration can request another at minimal cost and with the minimal amount of down-time. Furthermore, it is desirable that the customers be able to refurbish the carts at their own facility without specialized tooling and without having to ship the cart back to the manufacturer. 
   SUMMARY OF THE INVENTION 
   The modular drawer system of the present invention is designed to meet the requirements outlined above. 
   In one aspect, the present invention provides a modular drawer system comprising a frame, comprising a substantially rectangular base and at least four support columns extending from the base; at least four corner column trim pieces, each being slidably connected to one of said support columns; a top, which is attached to said frame; at least one drawer bay comprising two drawer guide panels which are slidably connected to said frame by said corner column trim pieces; and, at least one drawer supported by said two drawer guide panels. 
   In another aspect the present invention further provides a releasable tracking mechanism for a cart that prevents at least one caster assembly from swiveling while allowing wheels of the caster assembly to continue to roll. In a further aspect the present invention provides a lock bar assembly for locking a plurality of drawers. In yet another aspect, the present invention provides a removable lock tray. Furthermore, another aspect the present invention provides a lockable lid for covering at least a portion of a drawer body. In another aspect, the present invention provides an accessory track that provides at least two different means for attaching accessories to a device. 
   Further aspects of the present invention will become apparent from the description provided below. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a front elevational view of a modular drawer system of the present invention illustrated with two drawer bays, caster assemblies and a shelf. 
       FIG. 2  is a side elevational view of the modular drawer system of  FIG. 1  with two the drawers in their open position. 
       FIG. 3  is an perspective view of the modular drawer system of  FIG. 1  with two drawer bays in their open position. 
       FIG. 4  is a fragmentary view of the modular drawer system of  FIG. 1  showing the shelf at a different height. 
       FIG. 5  is a perspective view of a modular drawer system of the present invention illustrated with a refuse container. 
       FIG. 6  is a front elevational view of the drawer system of  FIG. 5 . 
       FIG. 7  is a fragmentary perspective view of a modular drawer system of the present invention with a refuse container and handles. 
       FIG. 8  is an exploded perspective view of a frame illustrated with caster assemblies and a bumper assembly. 
       FIG. 9  is a perspective view of a frame, illustrated with caster assemblies and a bumper assembly. 
       FIG. 10  is a exploded view of an accessory track. 
       FIG. 11  is a perspective view of a caster assembly. 
       FIG. 12  is a top plan view of the caster assembly of  FIG. 11 . 
       FIG. 13  is a perspective view of the underside of a tracking mechanism of the present invention. 
       FIG. 14  is a fragmentary perspective view of the tracking mechanism of  FIG. 13 , wherein the locking pin and detent are not engaged. 
       FIG. 15  is a fragmentary perspective view of the tracking mechanism of  FIG. 13 , wherein the locking pin and the detent are engaged. 
       FIG. 16  is a exploded view of the foot pedal, connecting means and locking plates of the tracking mechanism. 
       FIG. 16   a  is a fragmentary elevational view, partially in cross section, of the foot pedal, and plunger of the tracking mechanism, and a protuberance on the underside of a bumper assembly. 
       FIG. 17  is an exploded view of a drawer guide panel and lock bar assembly of the present invention. 
       FIG. 18  is an perspective view of the drawer guide panel and the lock bar assembly of  FIG. 17 . 
       FIG. 19  is a fragmentary perspective view, partially in cross section, of a frame and drawer guide panels. 
       FIG. 20  is perspective view of the corner column trim piece attached to the support column. 
       FIG. 21  is a fragmentary perspective view, partially in cross section, of the lock bar assembly and drawer guide panel. 
       FIG. 22  is an exploded perspective view of a lock bar assembly of the present invention, illustrated with locking tabs on one side only. 
       FIG. 23  is an exploded perspective view of a lock bar assembly of the present invention, illustrated with locking tabs on two sides. 
       FIG. 24  is an fragmentary perspective view of the lock tray. 
       FIGS. 25 ,  26 , and  27   a,b,c  are plan views of extruded profiles. 
       FIG. 28  is a front elevational view of an end panel. 
       FIG. 29  is a fragmentary cross section through line  29 — 29  of  FIG. 28 . 
       FIG. 30  is a perspective view of a top. 
       FIGS. 31–35  are exploded perspective, top plan, front elevational, bottom plan and side elevational views, respectively, of a drawer. 
       FIGS. 36 and 37  are exploded perspective and perspective views, respectively, of a punch card drawer. 
       FIG. 38  is a perspective view of a punch card tub. 
       FIGS. 39 and 40  are exploded perspective and perspective views, respectively, of a drawer with a lockable lid. 
       FIGS. 41 and 42  are perspective and top plan views, respectively, of an accessory track. 
       FIGS. 43 and 44  are exploded perspective and perspective views, respectively, of the accessory bar. 
       FIG. 45  is an exploded perspective view of a handle. 
       FIGS. 46 and 47  are perspective and exploded perspective views, respectively, of a cart top organizer. 
       FIGS. 48 ,  49  and  50  are front elevational, side elevational and perspective views, respectively, of a label holder. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   While the present invention is described in the form of a medication cart, it is not so limited. The present invention provides for any drawer system wherein many of the components are slidably connected. More particularly, because the components are configured to be slidably interconnected, the present invention provides for a drawer system wherein the number of fasteners are significantly reduced over the number of fasteners required by drawer systems of the prior art. The slidable connectors also allow the drawer system of the present invention to be assembled quickly. Furthermore, once the frame, described below, has been assembled, the balance of the drawer system of the present invention can be assembled without the use of alignment fixtures or specialized tools. 
   As shown in  FIGS. 1–7 , the drawer system indicated generally at  10  of the present invention is a modular system comprising a frame  12  (shown in  FIGS. 8 and 9 ), a top  16  and drawer guide panels  18  (shown in  FIG. 19 ). The drawer system  10  can be used in any application where it is desirable to have lockable drawers  20 . The drawer system  10  can be used in stationary cabinetry with drawers  20  on one side of the cabinet, or on both sides of the cabinet, in a back-to-back arrangement. The drawer system  10  can also be supported by wheels or caster assemblies  22 . This drawer system  10  can be outfitted with various drawers  20  and other accessories to provide a customized system to meet the requirements of the customer. 
   Looking at  FIGS. 8 and 9 , the frame  12  of the present invention comprises a substantially rectangular base  24  with an upper and lower surface and a length and a width. The frame  12  further comprises support columns  26  that extend from the upper surface of the four corners of the base  24 . When more than one drawer bay  28  is desired, the frame  12  may further comprise at least two additional support columns  30  that are be disposed along the length of the upper surface of the base  24 . The additional support columns  30  must be situated so that one additional support column  30  is on one side of the base  24  and the other additional support column  30  is on the other side of the base  24 , and the two additional support columns  30  form a plane that is perpendicular to the length of the base  24 . The frame  12  may also include at least two transverse support rods  32  connecting the support columns  26 , which are disposed along a length of the frame  12 , to one another at the upper ends of the support columns  26 . The frame  12  does not require transverse support rods  32  when sufficient stability is provided by the top  16 , which is then attached to the support columns  26 . A suitable top  16  will be described in further detail below. 
   The frame  12  can be manufactured of any material of sufficient strength and rigidity to support the drawer system  10  and provide the necessary stiffness. Preferably, the material is long-lasting, corrosion resistant and lightweight. The frame  12  can be made of any structural material known in the art including structural polymers, particularly, for example, graphite or glass pre-impregnated polymers, wood, or metal, or any combination thereof. Preferably, the base  24  and transverse support rods  32  are made of tubular steel. More preferably, they are made of roll formed 1008 steel. Preferably, the support columns  26  and  30  are made from extruded aluminum. More preferably, they are made from extruded 6063-T6 aluminum. The overall size of the frame  12  is dictated by the desired size of the drawer system  10 . 
   The frame  12 , including the base  24 , the support columns  26  and the transverse support rods  32 , can be manufactured as one piece, e.g. molded as a single item, or it can comprise individual parts attached to one another by welding, bolts, bonding or any other attaching means. The frame  12  components can be produced by any methods, including, but not limited to, molding, casting, extruding and machining. It is not necessary for all components to be made in the same way. More preferably, the frame  12  comprises a base  24  made of components that are welded together. The support columns  26  are preferably bolted to the base  24  and to the transverse support rods  32 . 
   If a rolling drawer system  10  is preferred, then at least four caster assemblies  22  are attached to the underside of the frame  12 . Such caster assemblies  22  are preferably attached at the four corners of the frame  12  to maximize stability and ease of rolling. See  FIGS. 11 and 12 . The caster assembly  22  comprises a caster  34  and at least one wheel  36 . The caster  34  provides rotation to the caster assembly  22  about a vertical axis, as indicated by directional arrow  42 , and a means of attachment of the assembly to the frame  12 , such as a mounting stud  35 . The wheel(s)  36  provide rotation about a horizontal axis, as indicated by directional arrow  44 . To minimize the number of components necessary to build a drawer system  10 , it is preferable that the means of attaching the caster assembly  22  to the frame  12  also act as a means of attaching a bumper assembly  72  to the drawer system  10 . Preferably, the mounting stud  35  of the caster  34  is inserted through a perforation  78  in the bumper  74 , thereby holding the bumper  74  in place, as shown in  FIG. 8 . 
   The caster assemblies  22  can be any type of caster assemblies  22  known in the art. The caster assemblies  22  need to roll easily, support the weight of the drawer system  10  and its contents, and provide stability. While each caster assembly  22  can comprise one caster  34  and one wheel  36 , it is preferable that each caster assembly  22  comprise one caster  34  and two wheels  36 . In a caster assembly  22  with two wheels  36 , the wheels  36  are preferably disposed on either side of the caster  34 . Preferably, each wheel  36  is approximately 5″ in diameter. The caster  34  and wheel(s)  36  of each caster assembly  22  can be made of metal, thermoplastic, thermoset plastic, elastomeric materials, or combinations thereof. Preferably, the caster  34  and wheel(s)  36  are injection molded thermoplastic. More preferably, the wheel  36  includes an elastomeric band  38  that covers its perimeter. 
   Preferably at least one caster assembly  22  has a releasable tracking mechanism  40  that can be activated for all affected caster assemblies  22  from one point on the drawer system  10 . If the drawer system  10  includes a fifth caster assembly  22  that is located approximately in the center of the base  24 , it is preferable that the releasable tracking mechanism  40  act upon that fifth caster assembly  22 . More preferably, two caster assemblies  22 , located in a plane which is perpendicular to the direction of travel, have a releasable tracking mechanism  40 . When it is engaged, the tracking mechanism prevents the caster assemblies  22  from rotating around a vertical axis indicated by directional arrow  42  and aligns the wheels  36  parallel to the direction of travel of the cart. Because the caster  34  can no longer rotate about a vertical axis as indicated by directional arrow  42  but the wheels  36  can still rotate about a horizontal axis indicated by directional arrow  44 , this provides for easier steering of the drawer system  10 . 
   The tracking mechanism  40 , shown in  FIGS. 13–16 , can be activated by any mechanical or electromechanical means, including but not limited to a foot pedal  46 , a triggering device on the handle or elsewhere on the drawer system  10 , or by remote electronic means. Such a releasable tracking mechanism  40  preferably comprises a foot pedal  46  which activates it. The tracking mechanism  40  further comprises a locking plate  48  which causes a locking pin  50  to become engaged by a detent  52 . There is no limitation as to the location of the locking pin  50  and the detent  52 . The locking pin  50  can be located on the locking plate  48 , in which case the detent  52  is then located on the caster  34 . The locking pin  50  can also be located on the caster  34  and the detent  52  is located on the locking plate  48 . While there is no limitation on the configuration of the locking pin  50  and the detent  52 , it is preferable that the detent  52  include a means for allowing the caster assembly  22  to lock into place when the caster  34  is out of alignment at the time the tracking mechanism is engaged. Such means can include an angled guide ramp  54  which allows the caster assembly  22  to swivel into position until the locking pin  50  is captured by the detent  52  but does not allow the locking pin  50  to disengage from the detent  52  until the tracking mechanism is released. 
   The tracking mechanism can be released by means of the foot pedal  46 , as shown in  FIG. 14 . Preferably, the foot pedal  46  is located approximately in the center of the width of the frame  12 . Preferably, the foot pedal  46  includes a spring-loaded plunger  58  that moves from one side to the other side of a protuberance  56  located on the underside of either the frame  12  or the bumper assembly  72  when the foot pedal  46  is depressed. Preferably, the protuberance  56  is located on the underside of the bumper assembly  72 . When the plunger  58  is on one side of the protuberance  56 , the locking plates  48  are rotated such that the locking pin  50  is engaged by the detent  52 . Conversely, when plunger  58  is on the other side of the protuberance  56 , the locking plates  48  are rotated such that the locking pin  50  is disengaged from the detent  52 . Preferably, the foot pad is attached to the locking plates  48  by connecting means  60  which rotates when the foot plate is activated, causing the rotation of the locking plate  48  into position to capture the locking pin  50 , as shown in  FIG. 15 . 
   The locking plate  48 , locking pin  50  and the foot pedal  46  can be made of any material that can withstand wear, the force applied by the operator, and the force of the locking pin  50  as it slides into position. Such materials can include plastics, metals or combinations thereof. Preferably the foot pedal  46 , locking plate  48  and locking pin  50  are manufactured of thermoplastic. More preferably, the locking plate  48  and foot pedal  46  are made of glass reinforced Nylon. More preferably, the locking pin  50  and plunger  58  are made of materials that exhibit toughness, good lubricity and good wear characteristics. Most preferably, the locking pin  50  and plunger  58  are made of acetal. The tracking mechanism components can be made by any means known in the art, preferably they are injection molded or compression molded. The connecting means  60  between the foot pedal  46  and the locking plate  48  can be made of any material. Preferably the connecting means  60  is made from a material that can provide stiffness in a compact design. The connecting means  60  are more preferably made of metal. Even more preferably, it is made of steel. Most preferably, the steel is plated for corrosion protection. 
   At least one of the caster assemblies  22  may further comprise a wheel lock  70  that prevents the wheel  36  from rotating about the horizontal axis indicated by directional arrow  44  and thereby prevents the cart from rolling. Such wheel locks  70  are well known in the art. There is no limitation on the type of wheel lock  70  that can be used in the present invention. 
   The four support columns  26  extending from the base  24  at its four corners include means for holding an extruded covering, side and back panels and accessory tracks, all of which will be described in greater detail below. 
   As  FIG. 8  shows, when the drawer system  10  is supported by caster assemblies  22 , a bumper assembly  72  is preferably attached to the perimeter of the base  24 . This bumper assembly  72  prevents damage to the drawer system  10 , walls, woodwork, doorways, etc. It also provides a more pleasing appearance as the bumper assembly  72  can be colored to customer specifications. Such a bumper assembly  72  is preferably made of an impact absorbing material such as plastic, rubber, an elastomeric material, or some combination thereof. More preferably, the bumper assembly  72  comprises a rigid compression molded bumper  74  with an elastomeric bumper pad  76  attached to its perimeter. The bumper pad  76  can be attached by a snap lock feature, bonding, or by molding onto the bumper  74 . More preferably, the bumper pad  76  is molded onto the bumper  74 . 
   The bumper assembly  72  can be attached to the frame  12  by any means known in the art, including a snap lock feature, fasteners or bonding. Preferably, it is locked in place by the insertion of the caster assemblies  22  as described above. 
   Looking at  FIGS. 17–19 , and  21 , at least two drawer guide panels  18  are inserted into the frame  12 . These drawer guide panels  18  are preferably located at both ends of the frame  12 . The drawer guide panels  18  comprise a panel  80  having numerous guide rails  82 . A drawer slide  124  of a drawer  20  is supported by the guide rails  82  of the drawer guide panels  18 . The drawer guide panels  18  preferably extend substantially across the width of the base  24  and extend substantially the height of the frame  12 . 
   To minimize the number of different pieces that need to be manufactured, while maximizing the flexibility to manufacture a cart to a customer specification, the drawer guide panels  18  are preferably made of at least two components  84 , as FIG.  17  shows. In the most preferable configuration, a single drawer guide panel  18  is made of two individual components  84 . Preferably, each component  84  is either a five guide rail configuration or a four guide rail configuration. This allows the manufacturer to produce a drawer guide panel  18  that has 8, 9 or 10 pairs of guide rails  82  depending on whether a drawer guide panel  18  is made of two guide rail components  84  each with four pairs of guide rails  82 , two guide rail components  84  each with five pairs of guide rails  82 , or component  84  with four pairs of guide rails  82  and one guide rail component  84  with five pairs of guide rails  82 . 
   The drawer guide panels  18  can be made of any material that will withstand the wear caused by the constant sliding back and forth of the drawers  20 , and will support the weight of the drawers  20 . Such materials can include thermoplastics, thermoset plastics and metals. Preferably the drawer guide components  84  are injection molded, compression molded or thermoformed thermoplastic. If a drawer guide panel  18  comprises two or more components  84 , the components  84  can be held together by screws, bolts, rivets, bonding or a snap lock feature. Preferably, the drawer guide panel  18  comprises two components  84  that are fastened together with screws. 
   The drawer system  10 , shown in  FIG. 18 , may further comprise at least one lock bar assembly  86 . This lock bar assembly  86  prevents the unauthorized opening of the drawers  20  in the drawer system  10  when it is activated. The lock bar assembly  86  must be located such that it can lock and unlock the plurality of drawers  20  positioned on one side of the drawer system  10 . Should there be more than one drawer bay  28  on a side, a single lock bar assembly  86  can lock the drawers  20  in both drawer bays  28 . Should the drawer system  10  be a two sided system with drawers  20  on both sides of the system, then two lock bar assemblies  86  would be required, one for each side of the drawer system  10 . 
   Preferably, the lock bar assembly  86  is incorporated into the drawer system  10  in such a way as to minimize any tolerance stackup problems. More preferably, the drawer lock bar assembly  86  is attached to the drawer guide panel  18 . This ensures that the lock bar assembly  86  will line up properly with the drawer slides  124 , thereby minimizing any tolerance stackup problems. 
   As shown in  FIGS. 22 and 23 , the lock bar assembly  86  can include any means for locking the drawers  20  known in the art, including the locking means disclosed in U.S. Pat. No. 4,822,116, Relyea et al., issued Apr. 18, 1989, and incorporated herein by reference. Preferably, the lock bar assembly  86  comprises a lock column  88  and at least one lock bar  90 . The lock column  88  provides a means for attaching and locating the lock bar(s)  90  within the drawer system  10 . The lock bar assembly  86  can comprise either one lock bar  90  from which extends at least one lock stem  92  or it can comprise a plurality of lock bars  90 , each with at least one lock stem  92 . Preferably, the lock bar assembly  86  comprises a plurality of lock bars  90 . 
   Preferably, the lock column  88  and the lock bar(s)  90  extend substantially the height of the drawer guide panel  18 . More preferably, the lock column  88  includes a channel into which one lock bar  90  or a plurality of lock bars  90  slide. Most preferably, the lock column  88  is an extrusion with a substantially U-shaped profile. As  FIG. 18  shows, the lock column  88  can be attached to the drawer system  10 , preferably to the drawer guide panels  18 , by any means known in the art, including bonding, snap lock features, fasteners. It could also be molded or machined into the drawer guide panels  18  as an integral part of the drawer guide panel  18 . Preferably, the lock column  88  is connected to the drawer guide panels  18  with screws. 
   Each lock bar  90 , shown in  FIGS. 22 and 23 , has at least one means for locking a drawer  20  that allow the drawer  20  to be closed if it is open when the lock bar assembly  86  is activated. Preferably, this locking means comprises at least one locking stem  92  that can flex in only one direction in a horizontal plane, thereby allowing an open drawer  20  to be closed when the lock bar assembly  86  is engaged but not allowing a closed and locked drawer  20  to open while the lock bar assembly  86  is activated. More preferably, the lock stem  92  further comprises a locking tab  94  that blocks the motion of a corresponding capture mechanism  134  on a drawer slide  124  thereby preventing opening of the drawer  20 , and the geometry of the locking tab  94  and locking stem  92  is such that the stem  92  flexes only in one direction. When the drawer system  10  comprises two drawer bays  28 , the lock bar  90  must have two locking stems  92  for each drawer guide height. See  FIG. 23 . One locking stem  92  and tab is provided for each drawer  20  in each of the two bays  28 . One lock bar  90  can comprise two locking stems  92 . 
   Preferably, the locking tabs  94  extend through one of a plurality of holes  96  in the drawer guide panels  18 , allowing the locking tab  94  to contact the drawer slide  124 . See  FIG. 18 . The plurality of holes  96  are preferably arranged in a substantially vertical line. This vertical line of holes  96  can be located anywhere across the width of the drawer guide panels  18 . Preferably, it is located either close to one of the two edges of the drawer guide panels  18  or substantially in the center of the drawer guide panel  18 . More preferably, there are two lines of holes  96  in a drawer guide panel  18 , one line close to each edge of the drawer guide panel  18 . 
   At the top of the lock column  88  is a locking platform  98 , shown in  FIG. 17 . The platform includes the lock cam  100  ( FIG. 7 ), which is preferably wedge shaped. When the locking mechanism is activated, the lock cam  100  moves laterally thereby causing the lock column  88  to move downward, allowing the lock stems  92  to slide into position and causing the lock tabs  94  to block the motion of the drawer slide  124 . The lock cam  100  is connected to the lock  102  ( FIG. 24 ). Preferably, the connecting means are flexible so that the lock tray  104 , which will be described further below, can be removed from the drawer system  10  while still connected to the drawer system  10 . More preferably, the connecting means comprises a cable assembly. 
   As  FIG. 24  shows, the lock  102  is preferably contained in a lock tray  104  which can be accessed when the system is unlocked for easy replacement of any piece of the lock  102 . It is preferable that the lock  102  be a plunger-type lock comprising a lock button  103  and a lock shaft  105 : when the lock button  103  is pushed in, it causes a lock shaft  105  to move laterally, this lateral motion is translated through a cable assembly  101  to the lock cam  100 , causing the lock cam  100  to move the lock column  88  which slides downward to move the locking stems  92 , with their locking tabs  94 , into the locked position. The plunger mechanism provides a more reliable and more durable option than a cam lock, however any lock  102  known in the art can be utilized in the present invention. 
   The lock  102  is released by use of any means, including a mechanical key or an electronic release mechanism. Electronic mechanisms are well known in the art and include remote electronic devices and vibration detecting systems that determine when a cart is not in use and automatically lock the cart after a specified time period. Key releases  106  are also well known in the art. Any key release  106  known in the art can be used in the present invention. 
   The lock bar  90  and the locking stems  92  must be made of materials that exhibit good wear properties and are able to withstand being flexed. Preferably, they are made from injection molded thermoplastic. Any thermoplastic known in the art can be used; however, preferably the lock bar  90 , locking stem  92 , and locking tabs  94  are made of amorphous nylon. The lock bar  90 , locking stems  92  and locking tabs  94  are preferably molded as one piece. The lock bar  90  can comprise individual segments stacked together or one continuous piece. The locking platform  98  is preferably injected molded thermoplastic, more preferably it is Nylon. The lock cam  100  is preferably made of a different material than that of the locking platform  98 , so that the lock cam  100  and the locking platform  98  do not fuse together over time. Preferably the lock cam  100  comprises acetal. 
   As illustrated in  FIGS. 22 and 23 , the lock cam  100  and the lock  102  are preferably connected by a flexible connecting means  101  that must be able to translate the motion of the lock  102  to the lock cam  100  and provide for the flexible connection of the lock tray  104  to the drawer system  10 . Preferably, the connecting means comprises a cable assembly  101  that comprises a cable and a conduit through which the cable passes. The conduit serves to guide and constrain the motion of the cable. The cable can be made of any material that has sufficient stiffness to be able to push the lock cam  100 . Preferably, it is made of twisted wire. The conduit is preferably a multilayer conduit. More preferably, it is a three layer conduit comprising an inner liner that exhibits sufficient lubricity to allow the cable to slide through it without binding, a middle layer to provide stiffness to constrain the motion of the cable and an outer jacket that provides additional stiffness. Most preferably, the liner is made from acetal, the middle layer is braided wire tube and the jacket is extruded polypropylene. The pieces of the lock  102  can be produced by machining, injection molding, compression molding, or any other methods known in the art. 
   As  FIGS. 1 ,  3  and  5  show, if the lock  102  is contained in a lock tray  104 , the lock tray  104  is inserted into the drawer system  10  like the other drawers  20 , which will be further described below. It is preferable that the lock tray  104  be easily accessible to authorized personnel. The lock tray  104  should be able to be opened only when the drawers  20  in the cart are unlocked. The opening mechanism  108 , depicted in  FIG. 24 , for the lock tray  104  is preferably contained on the under side of the lock tray  104  and is accessible by opening the drawer  20  immediately below the lock tray  104 . Most preferably, it includes a release which must be pulled down, thereby clearing a retaining detent and allowing the lock tray  104  to slide out. 
   The drawer system  10  can include a retractable means  109  of providing information to the cart operators. This retractable means  109  can contain information about the features of the cart, the operation of the cart and any other information that the customer or the manufacturer wishes to include. Most preferably, the retractable means  109  includes a spiral bound notebook with pages that are laminated to provide durability. Such a means  109  includes a sliding tray that can be retracted into the drawer system  10  when not in use. Preferably this retractable means  109  is contained in the lock tray  104 . If it is housed in the lock tray  104 , it preferably includes a sliding tray which can be pulled out separately from the lock tray  104  whether the cart is locked or not. 
   As  FIG. 19  shows, if more than one column of drawers  20  are disposed along the length of a drawer system  10 , there will need to be two drawer guide panels  18  for each column of drawers  20 , so that each column of drawers  20  is supported by two drawer guide panels  18  that face each other. If two columns of drawer guide panels  18  are used on one side of a drawer system  10 , the lock bar assembly  86  is preferably located between the two columns of drawers  20  so that the locking stems  92  and their associated locking tabs  94  can extend into both columns of drawers  20 . This allows one lock bar assembly  86  to lock and unlock both drawer bays  28  on one side of the drawer system  10 . 
   In a configuration wherein drawers  20  are disposed on both sides of a drawer system  10 , the drawer guide panels  18  containing the lock bars  90  and locking stems  92  for the two sides of the cart are preferably disposed back to back so that they occupy an area between the two columns of drawers  20 . Drawer guide panels  18  hold drawers  20  on both sides of the drawer system  10 . Therefore, the drawer guide panels  18  preferably have holes  96  through which locking tabs  94  can extend on both ends of the drawer guide panels  18 . 
   The drawer guide panels  18  can be held between the sides of the frame  12  by any means known in the art. Preferably they are held in place at the ends of the drawer system  10  by four sliding corner column trim pieces  110 , one at each corner, as shown in  FIGS. 19 ,  20  and  25 . If more than one drawer bay  28  is desired in the drawer system  10 , additional drawer guide panels  18  necessary to provide the additional drawer bays  28  are held in place by sliding connectors  112 . Preferably, such connectors  112  are pieces with a substantially C-shaped profile, shown in  FIG. 26  that slidably connect the drawer guide panel  18  to the additional support columns  30  disposed along the length of the base  24 . This substantially C-shaped profile can have guide channels along its length to allow the connecting of other pieces, such as a side panel, to the drawer system  10 . This eliminates the need for any additional fasteners. Once the drawer guide panels  18  are in place in the frame  12 , a corner column trim piece  110  is slid down the length of each corner support corner column trim piece  110 . Lips on each corner column trim piece  110  hold a corresponding edge on the drawer guide panel  18  and on the support column  26 , thereby connecting the corner column trim piece  110  and the drawer guide panel  18  to each other and to the corner support column  26 . These corner column trim pieces  110  and connectors  112  can be metal or thermoplastic. Preferably, they are extruded, although they can also be machined. More preferably, they are made from extruded thermoplastic, most preferably they are extruded polyvinyl chloride. 
   To provide torsional stability to the drawer system  10 , an end panel  114 , depicted in  FIG. 28 , is preferably slid between the support columns  26  at the two ends of the drawer system  10 . See  FIG. 19 . The support column  26  should have a guide channel along its length to allow insertion of the end panel  114  without the need for any fasteners. Only practical considerations limit the material used to manufacture the end panel  114 . It should be lightweight, durable and relatively inexpensive. Preferably this end panel  114  comprises a sheet of thermoplastic. More preferably it comprises acrylonitrile butadiene styrene copolymer (ABS). The end panel  114  can be injection molded, thermoformed or extruded. It can also be made from extruded sheet machined to size. As shown in  FIG. 29 , locating means may be formed in the end panels  114  to ensure that the end panel  114  is properly positioned in the drawer system  10  and to provide a means of locking the end panel  114  in place in the drawer system  10 . Such locating means can comprise a groove  116  that runs substantially the length of the end panel  114  and that slides into the receiving channel in the support column  26 . Such locating means can be molded, extruded or machined into the end panel  114 . 
   When only one side of the drawer system  10  has drawers  20 , a sheet of material can be slid between guide channels to provide a back panel to a one-sided drawer system  10 . This back panel can be manufactured of any material used to manufacture the end panel  114 . Likewise, if only one drawer bay  28  is required on one side of a drawer system  10 , any other drawer bays  28  can be covered by a side panel like that used for the end panels  114 . A back panel or a side panel can be slidably connected to the drawer system  10  in the same manner as the end panels  114  are connected. Additional holding means, such as a specially profiled extrusions  118   a ,  118   b ,  118   c , such as those shown in  FIGS. 27   a ,  27   b  and  27   c , for slidably connecting a back panel or a side panel to the frame  12  may be attached to the support columns  26  or corner trim pieces  110 . Preferably, a specially profiled extrusion  118   a ,  118   b , or  118   c  is attached to the corner trim piece  110 . More preferably, it is attached with two sided tape. The back and side panel can be made from any of the materials used to manufacture the end panel  114 . 
   A top  16 , shown in  FIG. 30 , is placed on top of the frame  12 . See  FIG. 3 . The top  16  provides stability to the drawer system  10  because it connects the two sides of the frame  12 . If the frame  12  includes transverse support rods  32 , the top  16  serves to connect the transverse support rod  32  on one side of the frame  12  to the transverse support rod  32  of the other side. Transverse support rods  32  can also be molded into or attached to the top  16 . The top  16  can also replace the transverse support rods  32 . If the top  16  replaces the transverse support rods  32 , there are preferably stiffening means, such as ribs, molded or machined into the top  16  to provide the necessary stiffness and stability to the drawer system  10 . 
   The top  16  also provides a work surface. The top  16  can be attached to the transverse support rods  32 , or if it contains or replaces the transverse support rods  32 , to the support columns  26  by any means known in the art. Such attaching means can include fasteners, bonding, or a snap lock feature. Preferably, the top  16  is bolted to the transverse support rods  32 . The top  16  can be manufactured of any material known in the art that is sufficiently rigid and will withstand exposure to chemicals and medicines. It must be easily cleaned, aesthetically pleasing and durable. Preferably, it is made of a high pressure laminate covering a wood product, similar to that used for counter tops and other case goods, such as cabinetry. 
   It is also preferred that the top  16  have a top bumper  120  around its outer perimeter. This material can be the same as or similar to the bumper  74  material used around the base  24  of the frame  12 . It can be color coordinated so as to match the bumper  74  at the base  24  of the frame  12 . It can be thermoplastic, rubber or other elastomeric material, foamed or unfoamed. Most preferably it comprises polyurethane. 
   As previously described, drawers  20  can be inserted along one or two sides of the drawer system  10 . There is no limitation (other than practical considerations) on the configuration or size of the drawer  20  that can be utilized in the present invention. Drawers  20  typically comprise a drawer body  122  and two drawer slides  124 , one on each side of the drawer body  122 , as shown in  FIGS. 31–35 . Drawers  20  like those described in U.S. Pat. No. 4,822,116, Relyea et al, issued Apr. 18, 1989, incorporated herein by reference, can be used in the present invention. If drawers  20  are to be disposed along both sides of the drawer system  10 , it is preferable that the drawers  20  be of a depth of approximately one-half of the width of the drawer system  10 . 
   For a single sided drawer system  10 , drawers  20  that extend substantially the full width of the drawer system  10  are preferred. Such a drawer  20  preferably is attached to a telescoping drawer slide  126  that will allow the drawer  20  to be completely opened without falling out of the guide rail  82 . See  FIGS. 36 and 37 . Telescoping drawer slides  126  are well known in the art. There is no limitation on the configuration of telescoping drawer slide  126  that can be used in the present invention. The telescoping drawer slide  126  is preferably attached to the drawer guide panel  18  by fastening means, such as rivets or screws. The drawer guide panel  18  preferably includes at least one boss or molded-in insert  128  for receiving such fasteners, shown in  FIG. 18 . 
   Cassettes, as defined above, are well known in the art. One or more cassettes may be inserted into the drawer guides  126  of the drawer system  10 . There is no limitation on the type of cassette that can be inserted into the drawer system  10  except that it must include a suitable drawer slide  124  that will fit into the drawer guide panel  18 . Preferably, the cassette will include means of locking the cassette that are activated by the lock bar assembly  86  of the drawer system  10  when the cassette is inserted into the drawer system  10 . More preferably, the cassette will further comprise a locking system that can be engaged when the cassette is not held in the drawer system  10 . 
   As shown in  FIGS. 36 and 37 , a drawer frame  130  that does not include a bottom panel can also be used in the present invention. Such drawer frame  130  includes only side walls from which a removable tub  132  can be suspended. Such drawer frames  130  are known in the art as punch card drawers. A punch card is defined as a plastic or paperboard frame, typically 6″×9″, with blister packs covered with a foil seal for holding prescription medications. The drawer frames  130  allow tubs  132 , usually filled with patient medications held in punch cards, to be easily inserted and removed from a drawer system  10  without the need for removing individual punch cards from the tub  132 . See  FIG. 38 . 
   The drawers  20  can be made of any material that is lightweight, strong enough to withstand the required loads and will withstand exposure to chemicals and medicines. They can be made of metals, thermoplastics, or combinations thereof. It is preferable that the drawer body  122  be made of thermoplastic. It can be manufactured by any means known in the art including thermoforming, compression molding, injection molding, fabricating and combinations thereof. More preferably, the drawer body  122  is injection molded thermoplastic. It is most preferable that the drawer body  122  be manufactured of ABS. Preferably, the drawer slide  124  comprises an aluminum extrusion that is insert molded with a material that provides good wear characteristics as it slides on the drawer guide  82 , preferably polypropylene. 
   Drawer bodies can be of varying heights and widths. The heights and widths should be selected so that drawers  20  can be utilized in various combinations. For example, the drawer system  10  can have numerous very shallow drawers  20 , or one or two very deep drawers  20 , or a combination of shallow and deep drawers  20 . It is important that the overall stack-up of the drawer height for a given drawer system  10  configuration fit within the standard heights selected for the drawer systems  10 . Drawer bodies can also be narrow or wide. 
   As shown in  FIGS. 31–35 , along each side of a drawer  20  and extending substantially the entire width of the drawer system  10  are the drawer slides  124 . The drawer slides  124  extend beyond the depth of the drawer  20  to allow the drawer  20  to be slid to a completely open position without falling out of the drawer system  10 . The drawer slides  124  are supported between the guide rails  82  of the drawer guide panels  18 . It is important that the drawer slides  124  be disposed along the drawer  20  such that they are staggered with one drawer slide  124  being substantially one guide rail width higher than the other drawer slide  124 . This allows for drawers  20  to be disposed along both sides of the drawer system  10 . The staggered drawer slides  124  are further described in U.S. Pat. No. 4,822,116, Relyea et al, issued Apr. 18, 1989, incorporated herein by reference. 
   On the outer edge of each drawer slide  124  are capture mechanisms  134  for interfering with the locking tab  94 , shown in  FIG. 35 . Preferably there are at least two and more preferably there are at least three such capture mechanisms  134 , which allow the drawer  20  to be locked in any of three positions and to prevent a partially open drawer  20  from being opened further. Staggering the drawer slides  124  also allows any combination of drawers  20  to be stacked back to back with any other combination of drawers  20  on the other side of the drawer system  10 , as more fully described in U.S. Pat. No. 4,822,116, Relyea et al, issued Apr. 18, 1989, incorporated herein by reference. 
   As illustrated by  FIGS. 39 and 40 , one or more drawers  20  of the drawer system  10  can be outfitted with a lockable lid  136 . The lockable lid  136  can cover all of the drawer body  122  or a portion thereof. Such a lockable lid  136  is preferably made of a material that is able to provide a substantial deterrent to unauthorized access of the contents under the lockable lid  136 . More preferably, it is made of metal. Most preferably, it is made from individual strips  138  of metal that are held in a lid frame  140 . These individual strips  138  can be used for different sized drawers  20  to allow for standardized manufacturing. Preferably, the metal strips  138  are 6063-T6 aluminum extrusions and the lid frame  140  includes ABS side plates. 
   While the lockable lid  136  can be attached directly to the drawer body  122 , it is preferably and removably attached to the drawer body  122  by means of a drawer divider plate  142 . The drawer divider plate  142  preferably has attachment means, such as holes for receiving fasteners, for the lockable lid  136 . The drawer divider plate  142  is itself attached to the drawer body  122  by attachment means, such as screws or rivets. Attaching the lockable lid  136  to the drawer divider plate  142  allows the lid to be moved to another drawer  20  if preferred merely by unfastening the drawer divider plate  142  from the drawer body  122 . 
   The drawer divider plates  142 , with or without a lockable lid  136  attached, also provide means for subdividing a drawer body  122  into compartments. They provide slots into which individual dividers can be arranged to create compartments within the drawer body  122 . 
   The lockable lid  136  includes its own lock that is separate from the lock bar assembly  86 . The drawer  20  in which the lockable lid  136  is included will still be locked by the lock bar assembly  86  when the drawer system  10  is locked. This lockable lid  136  provides additional security for particularly sensitive items, such as controlled substances. Any commercially available lock can be used, preferably a cam lock cylinder is utilized. 
   A drawer  20  with a lockable lid  136  preferably includes a means for preventing the removal of the drawer  20  from the drawer system  10  when the system is unlocked. Such means are well known in the art and can include a spring loaded tab attached to the drawer slide  124 . 
   An accessory track  144 , see  FIGS. 41 and 42 , may be disposed along the length of the support columns  26  and is located so as to be accessible after the end panels  114  have been inserted, as shown in  FIGS. 8 and 10 . This accessory track  144  allows for the easy addition and removal of accessories to one or both ends of the drawer system  10 . Preferably the accessory track  144  comprises a plurality of plastic inserts  146  that include a bolt hole  148  in the center and tabs  150  for capturing accessory bars  152  thereby providing at least two different types of attachment mechanisms. More preferably the accessory track  144  also includes more than one captured nut so that some accessories can be screwed into the accessory track  144  for more secure installation. It is most preferable that the accessory track  144  be colored so that it is more easily visible. 
   Accessories can be attached to the accessory track  144  by accessory bars  152 . See  FIGS. 3 ,  5  and  7 . Preferably the accessory bar  152  comprises a spring loaded locking mechanism  154  that can be compressed to allow insertion of the locking mechanism  154  between the locking tabs  150  on the track  144  and then released so as to hold the locking mechanism  154  in place, shown in  FIGS. 43 and 44 . Such a locking mechanism is preferably made of injection molded plastic, however, it can also be made of metal. Accessories such as a refuse container  156  or a sharps container, are attached to the accessory bar  152  by any means known in the art. Preferably, such means comprises a telescoping holder  158  that allows the accessory to be extended away from the drawer system  10 . Any sharps container well known in the art can be used including, but not limited to, those manufactured by Becton Dickinson and Company, Franklin Lakes, N.J. 
   A handle  159 , shown in  FIGS. 7 and 45 , for ease of steering and pushing the drawer system  10  can be bolted to the nuts contained in the accessory track  144 . Such a handle  159  can be any configuration known in the art and is preferably attached by at least two bolts that screw into the nuts in the accessory track  144 . Similarly, an additional shelf  160  for extension beyond the end of the drawer system  10  can be bolted to the accessory track  144 . Such a shelf  160  can be made of any of the materials that can be used for the top  16 . Preferably the tray is bolted with brackets to the nuts in the accessory track  144 . More preferably nuts are provided at more than one height, and most preferably at four different heights, so that the shelf  160  and/or handle  159  can be located at more than one height, depending on customer preference. See  FIGS. 1–4 . 
   As shown in  FIGS. 46 and 47 , the drawer system  10  can further comprise a cart top organizer  162  that rests on the top  16  and can be used to store frequently used supplies. Such a cart top organizer  162  is preferably compartmentalized. It can be manufactured of any materials. Preferably, it is injection molded or thermoformed thermoplastic. Such a container preferably includes at least one recess  164  for holding items that extend above the cart top organizer  162 , such as a stem  166  on which an eye level medication platform  168  can be located. Such a stem  166  has a slidably connected medication platform  168 . This platform  168  can be located at the eye level of the individual dispensing the medication so that as liquid medication is poured into a dispensing cup, one can easily and accurately view the volume markings on the dispensing cup. Other recesses  164  can hold a work light, preferably such a work light has a movable arm to allow the light to be moved to where it is needed. 
   The drawer pulls  170  on each of the drawers  20  are preferably configured so that an operator is encouraged to pull the drawer  20  open from approximately the center of the drawer  20 . See  FIGS. 31 and 34 . More preferably, the drawer pulls  170  provide an opening  172  for the insertion of an operator&#39;s finger that is larger and more protruded approximately in the center thereby encouraging the drawer  20  to be pulled from the center. 
   Labels can be removably attached to the face of the drawers  20 , as shown in  FIGS. 48–50 . A label holder  174  encapsulates the label such that any liquids that are dripped on the cart will not get between the label holder and the label. Preferably the label holder  174  comprises a clear plastic sheet that has been bent into a configuration such that it follows the contour of the drawer  20  face, clips over the back of each drawer  20  face, and prevents liquids from dripping into the label and holds the label in place. More preferably, the label holders  174  are made of acrylic or polycarbonate. 
   Drawer systems  10  of the present invention can be any length and width and height. The length is dictated by the configuration of drawers  20 . There can be one or more columns of drawers  20 , limited only by the overall cart size that a customer is willing to accept. As noted previously, the combinations of drawer configurations are numerous and can be customized to meet each customer&#39;s requirements. The drawer system  10  can be stationary or it can be a rolling cart. Accessories can be attached on neither end, one end or both ends of the drawer system  10 . The drawers  20  can be disposed along one or both sides of a drawer system  10 .