Cassette assembly and unit dose medication cart using the cassette assembly

A medication cart features a frame assembly formed from a plurality of vertical support posts and wall panels secured to the posts. Each support post has a plurality of equally-spaced, radially extending flanges running the longitudinal length of the post. The medication cart contains, in addition to an array of drawers and bins, a multi-level cassette assembly. An internal locking mechanism secures the cassette assembly when it is positioned in the medication cart, and an external locking mechanism secures the cassette assembly outside of the medication cart.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates generally to a mobile cart for storing and 
transporting items, and more particularly to a medication cart featuring a 
cassette assembly ideally suited for storing and dispensing medication. 
2. Description of the Prior Art 
Mobile medication carts for storing medical and related patient supplies 
have been used for many years. Medication carts are typically used in 
hospitals or other health care facilities, and are wheeled from room to 
room transporting, for example, medication to be dispensed to patients. 
Two well-known medication carts are manufactured by Drustar.RTM. and 
Artromick Int'l..RTM.. Both medication carts use a cart frame supported on 
casters and are designed to receive an array of drawers, multi-level 
cassettes, shelves, etc. Each level of the cassette contains a plurality 
of pull-out bins, with the bins on different levels sometimes varying in 
size (i.e., width). Both medication carts also provide locking systems for 
securing the medication and other items in the cart. 
In addition, Artromick Int'l..RTM. offers a patented drawer slide module, 
which is the subject of U.S. Pat. No. 5,211,461, for use with their 
medication cart. 
The assignee of the subject application also manufactures and sells 
medication carts. In one type of mobile cart, known as the METROFLEX.RTM. 
cart, two interlocking side/bottom panels are joined together to form the 
lateral sides and bottom of the cart and a back panel is secured to the 
side/bottom panels. A top portion is added to complete a 3-sided enclosed 
cart. The interior sides of the cart are corrugated to support an array of 
differently sized drawers and bins, and shelves or other accessories can 
be provided on the outer sides of the cart. The METROFLEX.RTM. cart is the 
subject of U.S. Pat. Nos. 5,016,948 and No. D 323,915. 
However, further improvements in medication carts are desired. For example, 
there is a need for a medication cart with increased versatility and 
storage capacity as well as offering superior construction and features. 
SUMMARY OF THE INVENTION 
It is a principal object of the invention to provide an improved medication 
cart. 
Accordingly, one object of the present invention is to provide a medication 
cart with superior functional and aesthetic design features. 
In accordance with one aspect of the invention, a cart comprises an 
enclosed structure including a plurality of support posts, at least two 
side walls supported between the support posts, with each side wall have a 
corrugated interior surface, a bottom platform supporting the support 
posts and the side walls and a top platform fitting over the support posts 
and the side walls. In addition, locking means secures the enclosed 
structure, and a cassette assembly is removably supported in the enclosed 
structure. The cassette assembly includes frame means having side panels 
with a corrugated interior and ribbed outer surfaces which engage the 
corrugated interior surface of the side walls. At least one cassette tray 
is supported in the frame means, and at least one bin is received in the 
cassette tray. In addition, internal locking means secures the bins in the 
enclosed structure and external locking means secures the bins within the 
frame means. 
Another object of the invention is to provide a controller for controlling 
operation of the locking means. 
Another object of the invention is to provide a cassette assembly for use 
in the medication cart. 
Yet another object of the invention is to provide a cassette assembly that 
can be secured when disposed in the medication cart and secured when 
removed from the medication cart. 
In accordance with another aspect of the invention, a cassette assembly 
comprises frame means including side panels with corrugated interior 
surfaces and ribbed outer surfaces, at least one cassette tray slidably 
supported in the frame means, and at least one bin received in the 
cassette tray. Internal locking means secures the bin in an enclosed 
structure, and external locking means secures the bin within the frame 
means. 
Still another object of the subject invention is to provide a medication 
cart using a platform system featuring flanged support posts and offset 
side panels. 
In accordance with another aspect of the invention, each support post in 
the medication cart includes an elongated tubular post and a plurality of 
spaced flanges extending radially from the post and running in a 
longitudinal direction along the post. Each flange has a first portion 
extending radially from the post and a second portion extending from a 
terminal end of the first portion. 
These and other objects, aspects, features and advantages of the present 
invention will become apparent from the following detailed description of 
the preferred embodiment taken in conjunction with the accompanying 
drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 illustrates a medication cart 10 in accordance with the present 
invention. Generally, the cart includes a frame assembly 12 supported on 
casters 14. A plurality of drawers 16 of various sizes (i.e., depths) are 
slidably supported in the frame assembly, and hinged side pods 18 are 
supported on the sides of the cart to swing out toward the front as 
discussed in detail below. 
The medication cart features a cassette assembly 20 that includes a 
plurality of pull-out cassette bins provided on different levels. In 
accordance with the subject invention, the medication cart includes a 
security system for preventing unauthorized access to the drawers and the 
cassette bins, and the cassette assembly includes its own security system 
for securing the bins even when the cassette assembly is not in the cart. 
Details of the frame assembly 12 are shown in FIGS. 2 through 8. The frame 
assembly is based on a platform system using a plurality of flanged 
support posts and side panels. 
A support post 30 in accordance with the subject invention is illustrated 
in FIGS. 2, 3 and 4. The support post 30 is generally comprised of an 
interior post 32 and a plurality of radially extending, equally spaced 
flanges 34. The post is designed to be vertically disposed in normal use 
and can be supported at its lower end by a base platform, a foot, a 
caster, etc. In a single-wide platform, which is preferred for the 
medication cart, four support posts are used together to provide corner 
supports for the frame assembly. 
The interior post 32 is preferably tubular in shape, with a circular 
cross-section and interior 36 and exterior 38 concentric wall surfaces as 
best seen in FIGS. 2 and 3. The flanges 34 preferably extend along the 
entire longitudinal length of the interior post. In addition, the flanges 
and interior post are preferably formed by conventional extrusion 
techniques to form an integral structure made of, for example, aluminum. 
However, other comparable means, e.g., pultrusion, roll-formed steel, 
could be used to form the support post in accordance with the subject 
invention. 
The flanges 34, or dovetails, are preferably spaced equi-distant from each 
other around the periphery of the interior post 32 to create a symmetrical 
support post. Thus, four flanges would be spaced at 90.degree. intervals 
around the post. Although using four flanges is preferred because of the 
versatility such an arrangement provides, the number of flanges is 
arbitrary and can vary without departing from the scope of the invention. 
With reference to FIG. 3, each flange has a first portion 40 which extends 
radially from the interior post 32. At the terminal end of each first 
portion is a transversely-disposed second portion 42. The second portions 
are formed with arcuate outer surfaces 44, that together outline a 
circumference that is concentric with the interior 36 and exterior 38 wall 
surfaces of the interior post 32. Referring to FIG. 2, the outer surfaces 
44 of each flange are formed with a series of equally spaced 
circumferential grooves 46. The vertically-spaced grooves are desirably 
provided along the entire longitudinal length of the flanges. In one 
embodiment, the outside diameter of the support post, as defined by the 
arcuate outer surfaces 44, is 1.625" and the inside diameter is 0.875". 
A slot 48 is formed between each pair of adjacent flanges 34. Because of 
the arcuate shapes of the exterior wall surface 38 and the flanges, the 
slots can be described as substantially concave T-shaped, with respect to 
a longitudinal axis of the support post. With reference to FIG. 4, each 
slot is shaped to have concave-shaped opposite end surfaces 50 and 52. The 
exterior wall 38 forms a convex interior surface of the slot. The contour 
of the end surfaces and outer wall form a slot that is simple in design 
but provides maximum flexibility and support. In addition, the curved 
single-wall design of the flanges makes extrusion easier, is readily 
cleanable and allows the support posts to be aesthetically integrated into 
the finished structure as will be discussed in detail below. 
The frame assembly 12 in FIG. 5 is built on a single-wide platform 
constructed of four support posts 30. In this embodiment, the support 
posts support two exterior side panels 54 and a back panel 56 (unseen in 
FIG. 6). In addition, interior side panels 58 are disposed side-by-side 
adjacent to the exterior side panels 54. Top and bottom platforms 60 and 
62, respectively, complete the frame assembly. The top platform houses a 
mechanical locking mechanism 64 and an electronic controller 66, both used 
for operating a security system that will be described in detail below. 
The completed structure forms a 3-sided enclosed frame assembly, with the 
front side, or fourth side, open to receive an array of drawers, shelves, 
cassettes, etc., as discussed in detail below. 
Each interior side panel includes a corrugated interior surface 68 with an 
array of corrugations 70 adapted to receive and support drawers, shelves, 
cassette assemblies or other accessories. The horizontal corrugations are 
uniformly spaced in the vertical direction. Small, semicircular openings 
72 can be seen in the lateral front face of the interior side panel 
immediately below the end of each corrugation. The openings extend to the 
underside of each corrugation but cannot be seen in this view. The 
openings allow locking fingers, which will be positioned in each 
corrugations as discussed below, to move in and out of the corrugations as 
part of the security system that will be discussed below. Openings can 
also be provided along the right-hand side of the interior panel 58 for 
the same purpose. 
The top and bottom platforms 60 and 62 are preferably formed of a metal 
frame fitted with a plastic cover. As shown in FIG. 5, the top platform 
has a substantially rectangular shape for fitting over the four support 
posts 30. The bottom platform 62 is preferably designed, at least in a 
single-wide platform, to have a "C"-shape formed to have two extending 
legs 74 defining an open front portion 76. By cutting out the front 
portion of the bottom platform, the overall appearance of the cart is 
enhanced, especially when drawers or other accessories are not disposed in 
the lower part of the cart. 
Both top and bottom platforms can be secured to the support posts by using 
threaded plugs (unshown) that are force-fitted, for example, in opposite 
ends of each support post and threaded fastening means fed through the top 
and bottom platforms and into the plugs. In assembling the enclosed frame 
assembly, each support post is positioned on the base platform fitted with 
its cover, and a threaded bolt or other fastener is inserted through a 
hole in the platform from the underside and into engagement with the 
threaded plug. The side panels are then top loaded into the support posts. 
Threaded fasteners are inserted through the metal frame of the top 
platform and into the plugs at the top ends of the support posts. Finally, 
the top cover is fitted over the top platform. Of course, other comparable 
means for securing the platforms to the support posts could be used. 
In the single-wide platform design as discussed above, the enclosed frame 
assembly preferably has one support post 30 positioned at each of four 
corners. In this design, the support posts are spaced, for example, 19.8" 
from center to center. Of course, the spacing of the posts is arbitrary 
and can be varied to construct different size and shaped structures. A 
"double-wide" design platform includes, in addition to four corner posts, 
a rear center post and, in an enclosed frame assembly, a front center 
post. 
A slightly modified interior side panel 58' is shown in FIG. 6. The 
modified side panel 58' differs from the side panel 58 only in that each 
corrugation 70 is formed in two halves to define a dividing slot 74 that 
runs the vertical length of the side panel. The modified panel can be used 
in a two-sided enclosed structure, i.e., a dual access cart, whereby the 
front and back are open to receive, for example, a cassette assembly or 
drawers. In a dual access cart, a thin, flat panel (unshown) can be 
secured in the dividing slot 74 for dividing the interior of the frame 
assembly in half. 
A recessed opening, or pocket, 76 in the lower part of the interior surface 
68 and pockets 78 in the back of the interior side panel 58' (and 58) are 
provided to house various components of the security system. Offset 
lateral ends, or edges, 80 of the interior panel are received in slots 48 
in the support posts as discussed below to secure the side panel. 
All of the side panels can be made of a polymer material, e.g., 
polyethylene, and are preferably blow molded or formed by other comparable 
means to form a hollow, two-faced structure. The interior side panels 58 
are also compression molded in part as discussed below. 
FIGS. 7A and 8 are top views of the support posts 30 engaging side panels 
in accordance with the present invention. As discussed above, the side 
panels are top-loaded into the slots 48 of the support posts and rest on 
the bottom platform, or base, 62. 
FIG. 7A is a partial top view of the support post 30 in use as a right rear 
support (with reference from the front side of the cart). Clockwise in 
this figure, the support post 30 secures an interior side panel 58, a back 
side panel 56, a blank extrusion 80 and an exterior side panel 54. The 
blank extrusion 80 is essentially a linear trim piece of molded plastic, 
preferably extending the length of the support post, that is inserted into 
an empty slot 48 for aesthetic purposes, i.e., to provide a finished look 
to the enclosed structure. 
As FIG. 7A shows, each side panel is shaped to have a neck portion 82 and a 
head portion 84 forming each lateral end for engagement in the support 
post. The head portion is shaped to compliment the shape of the slots 48. 
In addition, each neck portion is offset from its respective panel. Using 
the exterior side panel 54 in FIG. 7A as an example, and using the 
coordinate system in FIG. 7B as a reference, the side panel has a 
longitudinal axis A running in the heightwise direction (in the Z-axis 
direction), a lateral axis B in the widthwise direction (Y-axis) and an 
orthogonal axis C representing its depth (X-axis). Axis C is orthogonal to 
both axes A and B. Likewise, the head portion 84 has its own longitudinal 
axis E, lateral axis F and orthogonal offset axis G. In accordance with 
the subject invention, the offset axis G of the head portion is transverse 
to the lateral axis B of the panel. In this manner, a contour fit is 
achieved between the panels and the support posts. As will also be 
appreciated, lateral axes M of the flanges 34 extend in directions either 
parallel with or perpendicular to the lateral axes (axis B) of the panels 
they secure. This arrangement allows the support posts to be visually 
integrated into the structure and provide a clean, aesthetically-pleasing 
appearance. 
FIG. 8 illustrates a support post 30 in use as a right front support in an 
enclosed structure. In FIG. 8, the slots 48 in the support post 30 receive 
an exterior side panel 54, an interior side panel 58 and a blank extrusion 
80 in the same manner as described above in FIG. 7A. In the remaining slot 
is secured a drawer-abutting extrusion 86 for abutting, e.g., a drawer 16 
that is slidably received in the enclosed frame assembly. As discussed in 
detail below, the drawer is provided with a surface, e.g., one or more 
ribs, that is slidably supported on the corrugated surface 68 of the 
interior side panel 58. As shown in FIG. 8, the drawer-abutting extrusion 
86, which is preferably a resilient plastic, includes an abutting face 88 
for contacting the fully closed drawer and a locking face 90 for 
contacting a part of the drawer and preventing it from being accidentally 
pulled out. 
A multi-level cassette assembly 20 in accordance with the present invention 
is shown generally in FIG. 9. A frame 102 of the cassette assembly is 
formed by a top component 104, which includes a handle 106, a plurality of 
side panels 108, a bottom component 110 and a back panel (unshown). The 
bottom component can be essentially the same piece as the top component 
but does not include a handle. An isolated view of the top (or bottom) 
component 104 is provided by FIG. 10. 
The multi-level cassette assembly supports a cassette tray 112 on each 
level, and each cassette tray contains a plurality of pull-out cassette 
bins 22. A lock 114, which is part of an external locking mechanism, is 
secured in a front face of the top assembly. While the cassette assembly 
in this figure provides three levels, the number of levels (which 
corresponds to the number of cassette trays) can of course vary without 
departing from the scope of the invention. The components comprising the 
cassette assembly are preferably made of a polymer plastic, e.g., ABS, and 
can be formed by conventional molding techniques. 
The side panels 108 are shown in detail in FIGS. 11 and 12, with FIG. 11 
illustrating a right side panel for use on the right-hand side of the 
cassette assembly and FIG. 12 showing a left side panel for use on the 
left-hand side of the cassette assembly. A single right and left side 
panel are used for each level of the cassette assembly. Each side panel is 
preferably an integrally formed piece of molded plastic. 
With reference first to FIG. 11, the side panel includes a lateral face 116 
formed with two elongated ribs 118. The ribs are shaped to complement the 
corrugated surface of the interior side panels 58 as discussed above. At 
the front of each rib 118 is an open slot 119 for receiving a component of 
the security system which will be discussed below. The top and bottom 
edges of the side panel are provided with a plurality of male/female 
connectors 120/122 for snap-fitting the side panel to other side panels or 
top or bottom components when assembling the cassette assembly. The male 
connectors 120 are best seen in FIG. 12. 
At the rear end of the side panel is formed a U-shaped panel interface 124 
for receiving the flat back panel of the cassette assembly. A front edge 
126 of the side panel is formed to have both an elongated slot 128 and a 
through-hole 130 running through it. The slot receives part of the 
external locking mechanism that will be described below. A hollow rod 
(unshown) made of, for example, aluminum is inserted through the hole and 
stabilizes the assembled cassette frame. 
FIG. 12 best illustrates the corrugated interior surface of the side panel. 
Corrugations 132 form a slot 134 therebetween for receiving the cassette 
tray 112. Elongated recesses 136 formed in the corrugations interface with 
the cassette tray in a manner described below. 
To assemble the frame, the side panels are snap-fitted together using the 
male and female connectors to provide as many levels as desired. The 
formed left and right sides can then be snap-fitted to the bottom 
component and a back panel can be fit into the panel interfaces in the 
side panels and into a portion of the bottom component. Hollow rods can 
then be loaded into the elongated holes 130 in both right and left side 
panels, and the external locking mechanism is positioned in the elongated 
slot in the right side panels. The top component can now be placed on the 
side walls. Screws or other fasteners are then inserted through holes 131 
in the top and bottom components and into threaded ends of the hollow rods 
to complete the assembly. 
The cassette tray 112 that is received in each level of the cassette 
assembly is shown in FIGS. 13 and 14. With reference to FIG. 13, the 
cassette tray is formed to have a flat bottom surface 138 surrounded on 
three sides by a vertical edge 140. At the front of the tray is a front 
face 142 which provides a small lip 144 at the front edge of the bottom 
surface 138. The edges on the left and right sides of the tray extend into 
horizontal ledges 146 for resting on the corrugation 132 in the side 
panels 108 of the frame. A channel 148 with a notched portion 150 is 
formed at the front part of the ledges. The notched portion is part of an 
internal locking assembly and will be engaged by a locking finger to 
secure the tray in the cassette assembly frame. 
FIG. 14 shows an underside of the cassette tray and illustrates a flexible 
latch 152 that forms part of the external locking assembly. The latch is 
cantilevered from the front face and includes, at its free end, an 
abutting face 154 and a sloping, or angled, face 156. The sloping face 
allows the latch to flex upwardly when receiving a horizontal force. A 
small block 158 located beneath the notched portion 150 will interface 
with the recess 136 in the corrugation 132 and indicate a normal stop 
position of the cassette tray as it is withdrawn from the frame. 
The cassette tray 112 supports a plurality of bins 22 as shown in FIG. 9. 
The size (i.e., width) of the bins can be varied to best fit the 
end-user's needs. For example, FIG. 9 shows a cassette assembly with 6 
bins supported on the top level, 4 bins supported on the middle level and 
3 bins supported on the lower level. An individual bin 22 is illustrated 
in FIG. 15. 
A bin label cover 160 for retaining a label on the bin 22 is shown in FIG. 
16. The label cover, which is preferably formed of clear or otherwise 
transparent plastic, includes front notches 162 and arcuate rear grooves 
164. The notches and grooves interact with small protrusions (unseen) 
inside the bin, and allow the label cover to pivot about the protrusions 
in the front notches. Identifying labels can thus be easily placed (and 
changed) between the label cover and a front face 166 of the bin. 
FIGS. 17(A)-17(C) show additional components of the external locking 
assembly. This locking assembly is designed to lock the cassette trays 112 
when the cassette assembly is removed, i.e., external, from the medical 
cart, hence the name "external locking mechanism." An internal locking 
mechanism in the frame assembly secures the cassette trays when the 
cassette assembly is inserted in the medication cart. 
With reference to FIG. 17(A), a bolt lock 168, which is mounted in the top 
assembly 104 as shown in FIG. 9, actuates a saw-tooth locking bar 170 to 
operate the external locking assembly. The bolt lock, which is 
conventional per se, includes a locking barrel 172 and an extended T-bolt 
174 that moves in and out of the barrel when a key is inserted into the 
lock barrel and turned 180.degree.. Bolt locks manufactured by the HURD 
LOCK Co. (H75N and H75C series), in Greeneville, Tenn., have been 
successfully used in the external locking assembly. Comparable assemblies 
besides the bolt lock could be used to actuate the locking bar without 
departing from the scope of the invention. A pin 176 extends from the 
T-bolt and engages an angled slot 178 in the flag-shaped top portion 180 
of the locking bar 170. A vertical slot 182 in the top portion interfaces 
with the top assembly 104 to vertically guide the locking bar. 
A partial front view of the locking bar 17 is shown in FIG. 17(B). The 
locking bar is preferably formed from metal, e.g., steel, and is shaped to 
include an elongated bar 171 and at least one locking tooth 184. A relief 
173 is shown at the lower end for metal forming purposes (i.e., to help 
bend the metal). Another relief for the same purpose is provided toward 
the upper end of the elongated bar 171. The elongated bar is formed, e.g., 
bent, to have an L-shaped cross-section as evident in FIG. 17(C). A first 
leg 173 of the bar fits in elongated slot 128 in the side panels. Only one 
locking bar is normally provided in each cassette assembly and usually 
disposed in the right side panels. A plurality of the teeth 184 are evenly 
spaced along the length of the locking bar. One tooth is preferably 
provided for each side panel and moves, with actuation of the locking bar, 
in and out of a locking position. In the locking position the tooth 184 is 
substantially even with the lower corrugation 132 (i.e., the bottom of the 
slot 134). 
FIG. 17(A) shows the locking bar in the up, or locked, position, whereby 
the tooth 184 will engage the latch 152 on the underside of the cassette 
tray. In this position, engagement between the tooth and the abutting face 
154 of the latch will prevent the cassette tray from being withdrawn. 
If the cassette tray is already withdrawn when the external locking 
assembly is actuated, the shape and flexibility of the latch permit the 
tray to be inserted into the cassette assembly frame and subsequently 
locked. When inserting the tray, the flexible latch will bias upwardly 
when the sloping face 156 slides over the tooth, thus allowing the drawer 
to be inserted and locked. 
To unlock the cassette assembly, the bolt nut is actuated to move the 
T-bolt and thus the pin 176 in the direction of arrow x. This sliding 
movement forces the locking bar downward through a camming action between 
the pin and the angled slot 178. In the down position, the cassette tray 
is free to slide in and out of the cassette assembly frame. 
The external locking assembly has been disclosed in terms of locking the 
cassette trays. As will be appreciated, however, locking the cassette 
trays effectively locks the bins and prevents access to the contents 
therein. By virtue of the vertical lip 144 on the cassette tray 112 and 
the close fit between the structure immediately above the bins, i.e., 
either the front face of another cassette tray or the top assembly, the 
individual bins cannot be withdrawn unless the cassette tray is slid out a 
sufficient amount, e.g., one inch, such that the bin can be lifted over 
the vertical lip and then slidably withdrawn. Thus, by preventing the 
cassette tray from being withdrawn, the bins can be securely locked. 
Details of a drawer assembly for use in the medication cart are shown in 
FIGS. 18 through 26. In accordance with the subject invention, the drawer 
assembly features an open architecture type of construction which uses one 
standard type of drawer frame for drawers of different sizes, i.e., 
depths. 
A standard drawer frame 200 is shown in FIG. 18 to include two side panels 
202 fastened between a handle drawer front 204 and a rear panel 206. The 
handle drawer front 204 is shown in isolation in FIGS. 19(A) and 19(B). 
The front handle section, which is preferably molded plastic, is actually 
formed from two pieces for ease of production: a recessed front face 208 
and a handle 210. The recessed front face 208 shown in FIG. 19(A) includes 
opposite arms 212 that are secured, such as by threaded fasteners, to the 
side panels 202 of the frame. Each arm 212 includes a notched channel 214 
for receiving a locking finger as discussed in detail below. The notched 
channel 214 permits the drawer assembly to be securely locked in the 
enclosed structure. The plastic handle 210, as shown in FIG. 19B, is 
snap-fitted to the front face to complete the front handle section. 
The side panels and rear panel are formed of, for example, aluminum, and 
secured to each other by common fasteners 216, such as screws. Each side 
panel includes a formed channel 218 on its exterior surface for slidably 
receiving a drawer glide 220. The drawer glide, by virtue of its 
elongated, rectangularly-shaped outer side, slides between the 
corrugations 70 in the interior side panels 58 to support the drawer 
assembly in the enclosed frame assembly. 
As best seen in FIG. 20, which depicts a cross-section of the drawer glide 
220 and the side panel, the drawer glide has a T-shaped cross-section 
which complements the shape of the channel 218. The drawer glide is also 
provided with a cut-out notch 222 in its back surface. The notch extends 
from a rear end of the drawer glide to an intermediate, e.g., halfway, 
point of the drawer glide. The notch allows the drawer glide 220 to slide 
over the head of the screw 216 up to the intermediate point where the 
notch terminates. By allowing the drawer glide to slide relative to the 
side panel 202, the drawer frame can be pulled further out of the enclosed 
frame assembly to allow better access to the contents in the drawer. The 
intermediate end of the notch limits the relative movement between the 
drawer glide and the side panel to prevent the drawer glide from sliding 
out of the drawer frame. 
A drawer clip 224 as shown in FIGS. 21 and 22 is provided in each drawer 
glide 220 to prevent the drawer assembly from accidentally being pulled 
completely out of the medication cart. With reference to these figures, 
the integral drawer clip 224 is molded from a non-rigid plastic, such as 
nylon, to have a short leg 226 and a long leg 228. The long leg is formed 
with a stop 230, that includes a ramped portion 232 and an abutting face 
234, and a finger tab 236. The long and short legs meet to form an angle 
of approximately 100.degree., as best seen in FIG. 22, with the short leg 
fitting into an opening, such as slot 238, in the drawer glide. 
As shown in FIGS. 23 and 24, when the drawer clip is positioned in the 
drawer glide 220, it is almost flush therewith, except for the stop 230, 
which extends outwardly a short distance, e.g., 1/8." When pulling out the 
drawer assembly, the drawer glides slide along the corrugated side panel 
until the abutting face 234 of the stop 230 abuts the locking face 90 of 
the drawer-abutting extrusion 86 (see FIG. 8), at which point the drawer 
cannot be slid out further until the finger tabs 236 on each drawer clip 
are depressed into a recess 240 in the drawer glide. Depressing the finger 
tabs withdraws the stop and allows the drawer clips to pass by the 
drawer-abutting extrusions. Reinserting the drawer assembly is unimpeded 
because contact between the ramped portion 232 of the drawer clip 224 and 
the drawer-abutting extrusion biases the drawer clip inwardly, making it 
possible to slide in the drawer. 
FIGS. 23 and 24 further illustrate the open architecture type of drawer 
assembly. A single-depth drawer 16(A) in FIG. 23 shows a drawer insert 
242, which is essentially a 4-sided bin, supported on the drawer frame 
200. An isolated view of the bin 242 is provided in FIG. 25. The drawer 
insert includes a lip 244 for resting on the side and rear panels of the 
drawer frame, and can also include slots 246 for receiving optional bin 
dividers 248. Additional lateral dividers 250 can be positioned on the bin 
dividers 248 to further divide the drawer insert. One type of lateral 
divider is shown in FIG. 26 and is discussed below. 
In accordance with the invention, the drawer insert 242 can be of any 
desired depth. However, when the drawer insert is deeper than the handle 
drawer front 204 of single-depth drawer 16(A), the standard drawer frame 
200 is supplemented with one or more blank drawer fronts 252. For example, 
FIG. 24 shows a double-depth drawer 16(B), so-called because two-front 
sections a handle drawer front 204 and a blank drawer front 252, are 
secured together to form the front of the drawer assembly. 
For simplicity, drawer inserts 243 can be provided in standard depths of, 
for example, 3", 6" and 9". Each drawer front is sized to cover a 3" depth 
of the drawer insert. Therefore, a handle drawer front would be used with 
a 3" deep drawer insert, a handle drawer front and a blank drawer front 
would be used with a 6" deep drawer insert, and so on. For drawer 
assemblies of 6" and 9", a gusset 254 can be secured between the blank 
drawer front(s) 252 and the side panels 64 on each side of the drawer 
frame for additional rigidity. 
The lateral divider 250 shown in FIG. 26 includes a U-shaped cap 256 for 
fitting over a longitudinal divider 248 and scored sections 258 that can 
be snapped off where appropriate to adjust the length of the lateral 
divider. 
The side pods 18 are preferably secured to the medication cart by a hinge, 
such as a conventional piano hinge, so they can swing open toward the 
front of the cart. In FIG. 1, the side pods 18 are closed and positioned 
to rest against the sides of the cart. FIG. 27 shows the hinged side pods 
18 in the open position, with bins 260 in the side pods flanking the front 
side of the cart. 
FIG. 28 is a top view of the front right corner of the medication cart and 
illustrates a hinge 262 secured to the exterior side panel 54. The hinge 
mounts a back panel of the side pod 18 to the exterior side panel 54 and 
allows the side pod to pivot about hinge pin 264 to swing toward the front 
of the cart. Also shown in FIG. 28 is the interior side panel 58, 
drawer-abutting extrusion 86, blank extrusion 80 and, of course, the 
flanged support post 30. 
As best seen in FIGS. 29 and 30, the individual side pod is formed from two 
side panels 266 secured to a back panel 268. A utility shelf 270 is 
positioned between the two side panels. The side and back panels are 
preferably blow molded and secured to each other by conventional 
fasteners. The back panel is formed to have a plurality of vertical slots 
272 in its interior surface. The slots can be provided with tabs 273 for 
securing, for example, an unshown horizontal rail for supporting medical 
instruments, tools, and other accessories. As an additional feature, a 
vertical support (unshown), or bracket, can be key-fitted in a tab for 
supporting a partial-length horizontal shelf. 
With reference to FIG. 29 and the isolated view of a side panel 266 in FIG. 
31, the interior surface of the side panels 266 are formed to have a 
vertical array of molded, or configured, sections 274. Each molded section 
includes a horizontal slot 276 for supporting, as an example, a horizontal 
shelf 278, which is molded, or more particularly extruded, as shown in 
FIG. 32. The plastic shelf 278 is reversible and can be provided with a 
lip 280 along its front edge. In this manner, one side of the shelf 
provides a smooth, flat surface and the other side of the shelf uses the 
lip as an edge to help retain items supported on the shelf. Each molded 
section also includes a rear arcuate slot 282 and a front notch 284 for 
receiving a bin 260 of the type shown in FIG. 33. 
The bin 260 includes a handle 286 and two sets of pins 288 and 290 
extending from the lower lateral sides of the bin. For reference purposes, 
the first set of pins 288 is disposed directly below the handle and the 
second set of pins 290 is disposed opposite to the first set. To insert 
the bin in a frontward position, i.e., with the handle on the outside, the 
bin is tilted to place the first set of pins 288 in the notches 284 and 
the second set of pins 290 is guided into the arcuate slots 282. The bin 
can then be rotated into the cabinet to rest in an upright position. In 
this position, the bin can be tilted outwardly by holding the handle and 
rotating the bin about the first set of pins 288. The bin can also be 
mounted in a rearward position, i.e., with the handle on the inside of the 
cabinet, to provide a deep shelf. To achieve this position, the second set 
of pins 290 are first inserted into the notches 284 and the bin is tilted 
inward, with the first set of pins sliding in the arcuate slots 282. 
The side panels 266 also include a groove 292 running along the front inner 
edge for receiving a door 294, such as a tambour door, as shown in FIG. 
34. The tambour door, per se, is conventional and, as known, can be formed 
from a plurality of parallel sections joined together such as to exhibit 
flexibility in one direction and rigidity in a perpendicular direction. 
FIG. 34 shows the door secured to a locking shelf 296 positioned in an 
uppermost horizontal slot 276 in the side pod. The locking shelf can be 
formed by modifying the shelf 278 shown in FIG. 32 to provide a slightly 
enlarged front edge for housing a simple manual locking mechanism 298 such 
as a key lock and a rotatable locking finger (unshown) for securing the 
tambour door. The locking shelf can be easily located in any horizontal 
slot in the side panels for altering the portion of the cabinet which can 
be secured to best fit the user's needs. For example, FIG. 35 shows the 
locking shelf 296 disposed at approximately the mid-portion of the side 
pod. 
Another feature of the swing-out side pods is the provision of a swing-out 
work surface 300 that provides additional work space when the side pods 
are in the open position. As shown in FIG. 27, the work surface is 
substantially a flat shelf, preferably a quarter-circle in shape to 
maximize the work surface area, and is secured to a top portion of the 
back panel of each side pod. When the side pods are closed, the work 
surface slides under the top platform 60 of the cart and out of sight. 
Since both side pods are preferably equipped with swing-out work surfaces, 
these work surfaces are secured at slightly different vertical heights on 
their respective side pods so they will avoid each other when sliding 
under the top platform. 
While the side pod is ideally suited to be swingably mounted to a 
medication cart as discussed above, it can also be mounted to the sides of 
the cart so as not to swing and, as additional non-limiting examples, 
mounted to a wall, a work station, or a stationary cabinet. The side pod 
could also be provided on its own wheeled cart or caddy. 
An internal locking assembly, or security system, with both manual and 
electric controls can be provided in the frame assembly to lock and secure 
the drawers and cassette assembly. In one application, the medication cart 
is used to store and transport items such as drugs or other medicine, 
surgical tools, etc. in the drawers and cassette assembly that should be 
secured to prevent unauthorized use or consumption. Generally speaking, 
the security system features an elongated locking bar disposed in one of 
the interior side panels 58. The locking bar is moved up and down along 
its vertical axis to actuate locking fingers, housed in the corrugations, 
to engage and lock the individual drawers and the cassette assembly. 
The security system is housed, for the most part, in the interior side 
panel 58. With reference back to FIG. 6, a recessed pocket 76 on the 
interior side panel 58 receives and secures therein an electric motor, an 
electronic control card and a backup battery (all unshown in this figure). 
The locking bar is positioned in an extended locking finger clearance 
pocket 78 formed in the rear side of the interior side panel. Two of these 
clearance pockets can be provided in the side panel, as shown in FIG. 6, 
to provide the option of mounting the locking bar in either side of the 
panel. However, only one locking bar is normally mounted in the side 
panel. 
A front and rear view of the locking bar 302 is shown in FIGS. 36 and 37, 
respectively. The elongated locking bar is preferably formed from metal, 
such as 0.075" steel (14 gauge), and includes two holes 304 at the top for 
interfacing with the mechanical locking mechanism as described below. As 
best seen in FIG. 37, a plurality of locking fingers 306 are secured along 
the length of the locking bar. The locking fingers are evenly spaced and 
will be housed in corrugations 70 of the interior side panel 58 when the 
locking bar is properly positioned. 
FIG. 38 illustrates a set of three "right-hand"locking fingers 306 to be 
secured on the locking bar 302. The right hand locking fingers will be 
housed in an interior side panel secured on the right side of the enclosed 
structure. FIG. 39 illustrates "left-hand" locking fingers for use on the 
left side of the enclosed structure. The fingers are preferably grouped in 
sets of three, or sometimes four, for ease of attachment to the locking 
bar. Each set of fingers is preferably an integrally formed structure made 
of a resilient plastic, such as nylon, to impart flexibility to the 
individual fingers. Each finger includes a lateral arm 308 and an angular 
tip 310. An extension 312 joins each arm to a common base 314. In a 
three-finger set, as shown in FIG. 38, the base 314 includes one scored 
section 316 for separating the fingers as necessary. The base 314 includes 
a plurality of holes 318 for receiving rivets or other fasteners for 
attaching the locking fingers to the locking bar. In addition, a rib 320, 
which is best seen in the left-hand fingers shown in FIG. 39, can also be 
provided as a stabilizer. The angular tip 310 includes an angled face 322 
and an abutting face 324, with a front face 326 joining the angled and 
abutting faces. 
FIG. 40 is a rear view of the interior side panel 58, showing the locking 
bar 302 positioned in the locking finger clearance pocket 78 in the left 
side (from the rear view) of the panel. As will be appreciated by those 
skilled in the art, the side panel in FIG. 40 can be formed by a 
combination of blow molding and compression molding. The middle portion of 
the panel is hollow as a result of the blow molding. However, a subsequent 
processing step, such as machining or compression molding, forms the 
locking finger clearance pockets 78 on the right and left sides of the 
panel. Part of the corrugations 70 can be seen in the locking finger 
clearance pockets. As seen from this view, each corrugation has an opening 
72 in its underside, with the opening extending in a semicircular shape to 
a lateral face of the side panel immediately below the corrugation. When 
the locking bar is positioned in the clearance pocket, as shown in the 
left side of the side panel in FIG. 40, a locking finger 306 is positioned 
in each corrugation. A partial front view of the corrugated side panel 58 
with two locking fingers 306 positioned in corrugations is shown in FIG. 
41. In this figure, the locking fingers are extending through the openings 
72 in the underside of the corrugations, and thus in their locked 
position. 
With reference to FIG. 40, the lower end of the locking bar is operably 
engaged to an electric motor 328. The electric motor and an unshown 
battery operate to actuate the locking bar 302 up and down along its 
longitudinal axis. A rotatable shaft 330 extends from the motor and has 
mounted thereon a cam 332 for engaging the locking bar. A shown in FIG. 
42, the cam can have a propeller-like shape so that each quarter turn of 
the shaft will raise or lower the locking bar. 
The electronic motor and the battery are controlled by an electronic 
locking mechanism that will be described below in detail. When the motor 
is operated to actuate the locking bar, the locking fingers likewise move 
up or down to extend the tip 310 either in or out of its respective 
corrugation. When the locking bar is in the "down", or home, position, the 
locking finger tips 310 extend through the openings 72 and engages the 
notched channel 214 (see FIGS. 23 and 24) in the drawer frame. In this 
locked position, the notched channel is engaged by the abutting face 324 
of the locking finger and the drawer cannot be withdrawn. With respect to 
the cassette assembly, the locking fingers in the locked position project 
through the slots 119 in the ribs 118 and engage the notched portion 150 
of the cassette tray. 
When the locking bar is raised and thus in the up, or unlocked, position, 
the locking finger tips 310 are retracted within the corrugations and the 
drawers slide freely in and out of the medication cart. Likewise, the 
cassette trays are free to slide in and out of the cassette assembly, and 
the cassette assembly itself can also be withdrawn from the medication 
cart. 
In accordance with the subject invention, even if a drawer or a cassette 
tray is not fully inserted in the enclosed frame assembly, e.g., a 
cassette tray is open, when the locking bar is in the locked position, the 
drawer or cassette tray can subsequently be closed and will automatically 
lock. This feature is made possible by the shape and flexibility of the 
locking fingers. For example, when a withdrawn cassette tray is closed 
after the locking bar is locked, the channel 148 of the drawer frame will 
abut the angled face 322 of the locking fingers. The angled face permits 
the sliding cassette tray to impart an upward force to the locking finger, 
which in response will flex upwardly and allow the cassette tray to 
continue sliding until the notched portion 150 receives the finger tip 
310. At this point, the locking finger will return to its unbiased state 
and lock the cassette tray. 
While the locking bar 302 can be actuated by the electric motor, it can 
also be actuated by operation of a mechanical locking mechanism. With 
reference to FIG. 43, the independent mechanical locking mechanism 333 
includes a key-operated lock 334 and a pin 336 extending from the lock. An 
S-shaped link 338 is secured to the interior side panel 58 by a retainer 
clip 340. One end of the link extends through the hole 304 in the top end 
of the locking bar and the other (second) end of the link is in contact 
with the pin 336. To raise the locking bar and lift the locking fingers, 
thus unlocking the medication cart, a key is inserted into the lock and 
turned to rotate the pin in the clockwise direction. This clockwise 
movement lowers the second end of the link 338 and therefor raises the 
first end of the link to lift the locking bar. 
The electronic locking mechanism is operated by an electronic control 
system. In FIG. 44, reference numeral 1900 schematically represents the 
cart or other enclosed structure, reference numeral 1700 represents the 
electronic control system for controlling the security system, reference 
numeral 1702 represents the central processing unit (CPU), reference 
numeral 1704 represents a display, reference numeral 1706 represents 
memory, reference numeral 1708 represents a clock and calendar, reference 
numeral 1710 represents a power supply, reference numeral 1712 represents 
a lock motor, reference numeral 1714 represents an input and output port 
(I/O port), reference numeral 1716 represents a motion sensor, reference 
numeral 1718 represents a battery warning light, and reference numeral 
1720 represents a keypad. Each of the items identified above are shown in 
block outline because they are well known, per se, and a specific type of 
construction is not critical to carrying out the invention or to a 
disclosure of the best mode for carrying out the invention. 
In more detail, CPU 1702 preferably comprises a microprocessor or the like, 
and is connected to display 1704, memory 1706, clock/calendar 1708, power 
supply 1710, lock motor 1712, I/O port 1714, motion sensor 1716, and 
keypad 1720. Display 1704 comprises a 16 character alphanumeric LCD 
display or the like and includes a battery warning light, and is also 
shown in FIG. 53. Memory 1706 comprises non-volatile memory, RAM, ROM, and 
the like. Power supply 1710 preferably comprises a rechargeable nicad 
battery, featuring unattended fast charging with automatic kick-down to 
standby charging. Power supply 1710 also allows for connection for wall 
powered use independent from battery presence or charge level. The power 
supply comprises circuity (not shown) to survive accidental connection to 
other than a supplied wall transformer, e.g., A.C. or D.C. of less than 30 
volts. Furthermore, the power supply 1710 also comprises a backup lithium 
cell, preferably with a life expectancy of over five years. The lock motor 
1712 is protected from peak turn on current by an active current limiting 
circuit (not shown). I/O port 1714 comprises a standard port for 
interconnection with a personal computer. Motion sensor 1716 is optional 
and could comprise, for example, a circuit using a limit switch that 
detects if the lock bar has reached an expected position. Keypad 1720 
(FIGS. 44 and 53) preferably comprises a membrane touchpad with ENTER key 
2910, CLEAR key 2912, 0 through 9 keys generally shown as 2950, and other 
operation keys including a LOCK key 2922, PIN key 2914, TIME key 2916, 
AUDIT key 2918, and ADD/DEL key 2920. The battery warning light on the 
display 1704 is illuminated by CPU 1702 if the battery power is below a 
predetermined level. 
A control program for the electronic control is stored in memory 1706, and 
preferably in non-volatile memory. The control program serves to perform 
locking, unlocking, and various supervisory functions in response to user 
input from keypad 1720. FIG. 45 depicts a flowchart representing the main 
operation of the control program. When left unattended, the system enters 
into a sleeping, or stand-by, mode to conserve power. User input, as in 
step 2002 in FIG. 45, awakens the system, which then performs functions in 
accordance with the keys pressed. 
If the user presses the 0-9 keys on keypad 1720, the control program 
branches in step 2004 (FIG. 45) to an unlock and auto-relock routine 1100. 
Turning to FIG. 47, in step 1102, the program inputs the ID and PIN from 
keypad 1720. 
Step 1102 is shown in more detail in FIG. 46. FIG. 46 depicts a routine for 
inputting and validating the ID/PIN. Step 1002 sets a count variable to 
zero. The program inputs the ID and PIN in step 1004. The ID comprises a 
two digit number (00-99), and the PIN comprises a four digit number 
(0000-9999). Together, the ID and PIN comprise a user code. Of course, 
these choices are exemplary and could be changed to allow any specified 
number of digits for each of the ID and PIN. In any case, if the ID and 
PIN are found to be valid in step 1006, then the routine returns. If the 
ID and PIN are not found to be valid in step 1006, then control branches 
to step 1008, where the count variable is increased. If the count variable 
is found to be greater than three in step 1010, then access is denied in 
step 1012. In step 1012, the security system will remain locked for a 
supervisory-selectable number of minutes (LOCKOUT TIME). However, if the 
count variable is found to be less than or equal to three in step 1010, 
then the routine returns to step 1004 to allow the user to enter the ID 
and PIN again. 
Assuming that the user has entered a valid ID/PIN, the FIG. 46 routine for 
inputting and validating the ID/PIN returns to the FIG. 47 unlock and 
auto-relock routine, as discussed above. The unlock and auto-relock 
routine in FIG. 47 continues processing with step 1104. In step 1104, the 
CPU 1702 controls the lock motor 1712 to unlock the cart. In step 1106, 
the control program begins a timing operation. To inform the user of the 
remaining time, the CPU 1702 controls the display 1704 to display a status 
message. The status message preferably includes an alternating display of 
"XX MIN TO RELOCK" and "BATTERY E(****)F", wherein XX represents the 
number of minutes until auto-relock, and the latter display represents the 
amount of charge remaining on the battery (hereinafter referred to as the 
"battery charge message"). Step 1100 checks to see if the time is up, 
i.e., if the time has reached an AUTO-RELOCK TIME. This time can be 
changed by a user's supervisor for security purposes. If time is not up in 
step 1110, then in step 1112, it is checked whether the LOCK key has been 
pressed. If not, then the program returns to display status step 1108. 
Once time is up in step 1110, or if the lock key has been pressed in step 
1112, then CPU 1702 controls lock motor 1712 in step 1114 to lock the 
cart. When the cart has been locked, CPU 1702 controls display 1704 to 
display a lock status display, preferably for about 15 seconds, after 
which the display is shut off. The lock status display preferably 
comprises an alternating "LOCKED" message and the above-described battery 
charge message. 
If the optional motion sensor 1716 is included in the electronic control 
system, then the control program being executed by CPU 1702 uses the 
motion sensor 1716 to determine if the locking operation was successful. 
Specifically, in step 1114, after the CPU 1702 has controlled lock motor 
1712 to lock the cart, the CPU receives signals from motion sensor 1716 
representative of a state of the limit switch. If the limit switch (not 
shown) remains open for 12 seconds, for example, the motor is turned off, 
and then step 1116 displays an "UNLOCK ERROR" rather than the 
above-discussed lock status display. Such unlock errors are stored in 
memory 1706, preferably in non-volatile memory. The motion sensor operates 
in the same manner to determine if an unlocking operation was successful, 
i.e., if the limit switch does not change states after 12 seconds, the 
motor is turned off and an error signal is displayed and stored in memory 
1706. 
While the cart is unlocked, and the unlock and auto-relock routine in FIG. 
47 is operating, the other functions of the main operation of the control 
program (FIG. 45) are available on an interrupt basis. Specifically, while 
the unlock and auto-relock routine in FIG. 47 is passing through the steps 
1108, 1110, and 1112, if the user presses any of the function keys (e.g., 
ADD/DEL, TIME, etc.), that respective routine (e.g., ADD/DEL, TIME, etc.) 
will be performed. Thereafter, the flow returns to the unlock and 
auto-relock routine and the timer (step 1106) is reset to begin counting 
down again from the maximum, predetermined auto-relock time. 
To unlock the cart, the user must enter a PIN, as described above; however, 
the user may wish to change his or her PIN for security purposes. Also, 
the supervisor may wish to change a user's PIN. FIG. 48 shows a "change 
PIN" routine 1300. This routine would be selected, as shown in FIG. 45, if 
the PIN key is pressed (step 2008). Returning to FIG. 48, in step 1302, 
the user (or supervisor) enters the user code (ID/PIN). Step 1302 follows 
the procedure of FIG. 46, as described above. Assuming that a valid ID/PIN 
has been entered, in step 1304 the prompt "NEW PIN" is displayed on 
display 1704, and the user may input a new PIN via keypad 1720. The new 
PIN is displayed in step 1306, by an alternating display between "NEW PIN: 
####" and "ENTER OR CLEAR." User input is accepted in step 1308 (during 
which time the alternating display continues). In step 1310, if the ENTER 
key has been pressed, then the new PIN is stored in step 1314. If in step 
1310, the ENTER key has not been pressed, then it is determined in step 
1312 if the CLEAR key has been pressed. If so, the routine returns to step 
1304 to input a new PIN (although not shown, if the user presses the CLEAR 
key twice, the routine ends). If the user has not pressed CLEAR (step 
1312), then the user has pressed neither CLEAR nor ENTER, therefore the 
routine returns to step 1308. 
Returning to FIG. 45, if the PIN key has not been selected in step 2008, 
then step 2010 determines if the TIME key has been selected. If so, then 
the change date/time/unlock time routine of step 1400 is selected. FIG. 49 
depicts this routine in detail. First, a valid ID/PIN is input in step 
1402. The current date is displayed in step 1404, e.g., by an alternating 
display of "DATE-##/##/##" and "ENTER OR CLEAR", which display continues 
during user input in step 1406. If ENTER has been pressed (step 1408), 
then the date is presumed to be correct, and the routine continues with 
step 1412. If ENTER has not been pressed (step 1408), then the CLEAR key 
is checked in step 1410. If the CLEAR key has not been pressed, the 
routine returns to step 1406. If the CLEAR key has been pressed, then flow 
passes to step 1414, wherein the user may enter the date. 
Step 1414 is shown in more detail in FIG. 50. In step 2402, the month is 
displayed, e.g., by an alternating display of "MONTH: ##(01-12)" and 
"ENTER OR CLEAR", which display continues during user input step 2404. If 
neither ENTER nor CLEAR (steps 2406 and 2408) have been pressed, then flow 
returns to step 2404. If CLEAR has been pressed (steps 2406, 2408), then 
the month is input in step 2412, and flow returns to step 2404. If ENTER 
has been pressed (step 2406), then flow continues with step 2410. 
In step 2410, the day is displayed, e.g., by an alternating display of 
"DAY: ##(01-31)" and "ENTER OR CLEAR", which display continues during user 
input step 2414. If neither ENTER nor CLEAR (steps 2416 and 2418) have 
been pressed, then flow returns to step 2414. If CLEAR has been pressed 
(steps 2416, 2418), then the day is input in step 2422, and flow returns 
to step 2414. If ENTER has been pressed (step 2416), then flow continues 
with step 2420. 
In step 2420, the year is displayed, e.g., by an alternating display of 
"YEAR: ##(00-99)" and "ENTER OR CLEAR", which display continues during 
user input step 2424. If neither ENTER nor CLEAR (steps 2426 and 2428) 
have been pressed, then flow returns to step 2424. If CLEAR has been 
pressed (steps 2426, 2428), then the year is input in step 2432, and flow 
returns to step 2424. If ENTER has been pressed (step 2426), then the flow 
ends. 
After routine 1414 (FIG. 50) ends, flow returns to step 1412 in FIG. 49. In 
step 1412, an alternating display of "TIME: ##:##" and "ENTER OR CLEAR" 
begins, and continues during user input step 1416. If neither ENTER nor 
CLEAR are pressed (steps 1418, 1420), flow returns to step 1416. If CLEAR 
is pressed (steps 1418, 1420), then the time is input in step 1424. If 
ENTER is pressed (step 1418), or the time has been input in step 1424, 
then flow continues with step 1422. Although not depicted herein, input 
time step 1424 is similar in function to input date step 1414, with the 
difference being that HOURS (00-24) and MINUTES (00-59) are input. 
In step 1422, an alternating display of "RELOCK: ##MIN" and "ENTER OR 
CLEAR" begins, and continues during user input step 1426. If neither ENTER 
nor CLEAR are pressed (steps 1428, 1430), flow returns to step 1426. If 
CLEAR is pressed (steps 1428, 1430), then the AUTO-RELOCK TIME is input in 
step 1434. If ENTER is pressed (step 1428), or the auto-relock time has 
been input in step 1434, then flow continues with step 1432. Although not 
depicted herein, input auto-relock time step 1434 is similar in function 
to input date step 1414, with the difference being that AUTO-RELOCK TIME 
(01-99 minutes) is input. As described above, once the cart has been 
unlocked for an amount of time equal to the AUTO-RELOCK TIME (see FIG. 47, 
step 1100), then the cart is automatically locked. 
In step 1432, an alternating display of "LOCKOUT: ##MIN" and "ENTER OR 
CLEAR" begins, and continues during user input step 1436. If neither ENTER 
nor CLEAR are pressed (steps 1438, 1440), flow returns to step 1436. If 
CLEAR is pressed (steps 1438, 1440), then the LOCKOUT TIME is input in 
step 1444. If ENTER is pressed (step 1438), or the lockout time has been 
input in step 1444, then flow of the routine ends. Although not depicted 
herein, input lockout time step 1444 is similar in function to input date 
step 1414, with the difference being that LOCKOUT TIME (01-99 minutes) is 
input. As described above, if invalid ID/PINs are thrice entered, then the 
system enters an access denied/lockout state (FIG. 46, step 1012), and 
stays in that state for a period of time equal to the LOCKOUT TIME. 
Returning now to FIG. 45, if the TIME key has not been pressed (step 2010), 
then the selection of the AUDIT key is checked in step 2012. Each time a 
user unlocks the cart, an access record is stored in non-volatile memory 
in memory 1706. The last 500 access records, for example, are retained in 
revolving fashion (i.e., the oldest records are deleted to make way for 
newer records). Each cart also has stored within it a unique cart 
identifier. Unlock errors are also stored in memory 1706. All of this 
information may be downloaded to a computer using the audit function (FIG. 
45, step 1500). The procedure is shown in more detail in FIG. 51. In step 
1502, the ID/PIN is input in the manner of FIG. 46. An alternating display 
of "CONNECT COMPUTER" and "ENTER OR CLEAR" begins in step 1504, and 
continues during input step 1506. After user input from keypad 1720 during 
step 1506, step 1508 checks to see if ENTER was selected. Presumably, the 
user will have connected the computer to I/O port 1714 before pressing 
ENTER. If the user instead presses CLEAR (steps 1508, 1510), then the 
routine branches to step 1514, where the battery charge message is 
displayed; thereafter, the routine ends. If neither ENTER (step 1508) nor 
CLEAR (step 1510) are pressed, then flow returns to step 1506. If enter 
has been pressed (step 1508), then flow advances to step 1512, wherein the 
information is downloaded. During step 1512, "DOWNLOADING INFO" is 
displayed, and then "DOWNLOADING DONE" when the process is completed. When 
the transaction is complete, the battery charge message is displayed, for 
about 15 seconds, in step 1514. In addition to access information, other 
information such as a list of user names, IDs, and PINs may be downloaded 
to the computer. 
In addition to the AUDIT function, a supervisor may also wish to add or 
delete users. If the AUDIT key is not pressed (FIG. 45, step 2012), flow 
advances to step 2014, wherein it is determined if the ADD/DEL key has 
been selected. If not, then flow returns to step 2002. If "YES," then the 
supervisor add/delete routine, step 1800, is performed. FIG. 52 depicts 
this routine in more detail. In step 1802, the ID/PIN is input and 
validated as in FIG. 46. In step 1804, the alternating prompt "ENTER ID OF 
USER" and "ENTER OR CLEAR" is displayed, while user input is accepted. The 
CPU 1702 looks up the PIN corresponding to the input ID from memory 1706 
in step 1808. If no PIN has been assigned to the input ID (step 1810), 
then an alternating display of "ID: ##, PIN: NONE" and "CLEAR TO CHG PIN" 
appears (step 1812). If, on the other hand, a PIN has been assigned to the 
input ID (step 1810), then an alternating display of "ID: ##, PIN: ####" 
and "CLEAR TO CHG PIN" appears (step 1814). After either step 1812 or 
1814, the flow branches to step 1816. User input is accepted in step 1816. 
If CLEAR is not pressed (step 1818), but the user has begun to enter 
another ID (step 1842), then flow returns to step 1808. By means of this 
procedure, the supervisor can "scroll through" user IDs and PINs by 
pressing numbers without hitting enter. If neither CLEAR nor an ID is 
entered (step 1842), then flow ends, and a battery charge message is 
displayed (not shown in FIG. 61). 
On the other hand, if the user has pressed CLEAR, then either the add user 
routine or delete user routine is chosen. Consider first the delete user 
routine. Assume, for sake of discussion, that the screen depicts an ID/PIN 
combination, e.g., "ID: 05, PIN: 1234". Where there is such an assigned 
PIN (step 1820), the display will now be changed to "NONE" (step 1832). If 
the user inputs ENTER in step 1834, then flow branches as in step 1836 to 
step 1838 to delete that user. If the user does not input ENTER in step 
1834 (but instead presses CLEAR or another key), then the routine ends 
(step 1836 branches to end) and a battery charge message is displayed. 
Consider next the add user routine. In this case, assume, for sake of 
discussion that the screen depicts an ID/PIN combination, e.g., "ID: 56, 
PIN: NONE". Because no PIN is assigned (step 1820), now step 1822 will 
remove the "NONE" display, and the user may input a new PIN in step 1824. 
If the user next inputs ENTER in step 1826, then step 1828 branches the 
flow to step 1830 to add the new ID/PIN. Thereafter, the routine ends and 
displays a battery charge message. If the user does not input ENTER in 
step 1826, then step 1828 branches the flow to end the routine, and a 
battery charge message is displayed. 
Note that the foregoing supervisor add/delete PINs routine, when a user is 
added, entails entry of user IDs and initial PINs; of course, users can 
change their own PINs as described above in the change PIN routine. If the 
supervisor needs a list of the user names, IDs, and PINs, the same may be 
obtained from the computer audit program. 
While the aforementioned computer audit program allows downloading of 
information from the security system 1700 to a computer, the system also 
allows programming and control of the electronic control system from an 
external computer. As in the downloading, I/O port 1714 is used as an 
interface. The date, time, supervisor PIN, user PINs, lockout time, 
auto-relock time, and any other controllable parameters may be programmed 
in an external computer, and then uploaded to the electronic control 
system through I/O port 1714. 
In any mode of operation of the control program (including, for example, 
unlock and auto-relock routine 1100, change PIN routine 1300, change 
date/time/unlock time routine 1400, audit for access record routine 1500, 
supervisor add/delete PINs routine 1800, and input and validate ID/PIN 
routine 1000), if the control program is awaiting user input, and a 
predetermined amount of time elapses without any input, then the control 
program exits the mode of operation or routine in question and returns to 
the main operation (step 2000 in FIG. 45). This improves security, for 
example, by automatically exiting from the supervisor add/delete PINs 
routine, if the electronic control system is left unattended in the middle 
of that routine. 
Thus, what has been described is a medication cart that includes a cassette 
assembly and uses flanged support posts as part of its frame assembly. The 
cassette assembly includes its own external locking assembly for securing 
its contents when disposed outside of the medication cart. The cassette 
assembly is also constructed to be used with an internal locking assembly 
of the medication cart. 
Although specific embodiments of the present invention have been described 
above in detail, it will be understood that this description is merely for 
purposes of illustration. Various modifications of and equivalent 
structures corresponding to the disclosed aspects of the preferred 
embodiment in addition to those described above may be made by those 
skilled in the art without departing from the spirit of the present 
invention which is defined in the following claims, the scope of which is 
to be accorded the broadest interpretation so as to encompass such 
modifications and equivalent structures.