Plastic autoclave tray and lid combination

A plastic autoclave enclosure for retaining and storing medical instruments and apparata which must be autoclaved includes a molded tray, a molded lid and a pair of oppositely disposed slide latches which are used to secure the molded lid to the molded tray. The molded tray has an outwardly extending flange and disposed therein a pair of spaced-apart keyhole slots. The slide latches are attached to opposite ends of the molded lid and include a protruding pin portion from each latch which has an enlarged head and this enlarged head is received by the corresponding keyhole slot. The base of the molded tray is configured with two spaced-apart ribs and the molded lid has a pair of spaced-apart ribs which define the top surface into three generally rectangular areas. The spacing and length dimension of the tray ribs is such that the base of the tray may be stacked onto the top of the lid thereby allowing a plurality of autoclave enclosures to be stacked one on top of the other.

BACKGROUND OF THE INVENTION 
The present invention relates in general to plastic autoclave tray 
enclosures in particular to a plastic autoclave tray and lid combination 
for medical and dental instruments, appliances, and implant prostheses. 
Some of the aspects of importance in the design of autoclave enclosures 
include handling, opening and storage convenience, weight, compactness, 
durability and versatility in accepting a variety of holders and retainers 
for the instruments and appliances. The present invention addresses some 
of these aspects in a novel manner providing improvements to what 
heretofore have been available. 
Although a majority of autoclave trays and enclosures are fabricated out of 
metal for durability, strength and versatility reasons, there are modern 
plastics whose heat resistance enables them to be used for autoclave trays 
and enclosures. Plastics have certain physical features that are 
advantageous when compared to metal and weight advantages over metal and 
provide the ability to easily provide unique styles and shapes for the 
enclosure which might not be readily producible in metal. 
Autoclave trays, cassette and enclosure designs which might be of interest 
in order to appreciate some of the aspects of the conventional design 
wisdom are disclosed in the following patents. 
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Patent No. Patantee Issue Date 
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5,098,676 Brooks, Jr. March 24, 1992 
5,002,319 Chandler March 26, 1991 
1,973,947 Enderle Sept. 18, 1934 
3,433,269 Sackett, Sr. March 18, 1969 
4,826,348 Brightman May 2, 1989 
3,179,287 Rickmeier, Jr. April 20, 1965 
3,091,488 Vander Sande et al. 
May 28, 1963 
805 909 Kulbel-Germany June 4, 1951 
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Brooks discloses a plastic sterilization and storage container which 
includes a lower tray portion and an upper lid portion. Disposed within 
the tray portion is a finger mat for supporting surgical instruments. The 
tray and lid are molded out of plastic and each includes an outwardly 
extending flange portion with the lid flange fitting over and around the 
tray flange. A metal clamp then pivots from the plastic lid over and 
around the overlapping flanges as a means to clamp the lid onto the tray. 
Chandler discloses a sheet metal latch apparatus which may be used to 
attach a cover or lid portion to a base container. 
Enderle discloses a lid and container combination in which a pivoting 
U-shaped latch is used to clamp together the outwardly extending flanges 
of both members. 
Sackett discloses a rapid access closure system in which a base container 
is covered by a lid each of which have an outwardly extending flange 
portion. The two flanges are secured together by a pin arrangement. 
Brightman discloses a coupling set for interlocking objects which includes 
first and second coupling elements each having an integral stud by which 
it is anchored to one of two objects to be interlocked. 
Rickmeier discloses a container and lid in combination each of which 
includes an outwardly extending flange portion. The lid is provided with a 
series of slot openings and the base container has a matching series of 
protruding extensions. A pivotal or swivel latch mechanism is attached to 
the lid and provides an interlocking arrangement when the lid is secured 
to the base container. 
Vander Sande discloses a rotary latch mechanism for use in securing 
together a base container and lid member. In this particular arrangement 
there are no outwardly extending flanges and the rotary latch relies 
principally on a spring clip and pin arrangement for securing the hinged 
lid in a closed position on the base container. 
The German patent discloses a hinged lid and tray combination including a 
front wall, two-part latch mechanism. The lid includes an extended pin and 
the base or tray portion includes a spring clip slot with inwardly 
protruding projections. The latching mechanism relies on the lid pin 
pushing through the tray projections and coming to rest at a point of 
clearance beneath the projections. The projections are spring-biased such 
that when suitable force is exerted on the lid the pin can be pulled back 
through the protruding portions in order to open the container. 
The plastic autoclave tray and lid combination of the present invention 
departs from the designs and features of these earlier references by 
providing a molded plastic, stackable design with a quiet, smooth and 
convenient latch design. 
SUMMARY OF THE INVENTION 
A plastic autoclave enclosure according to a typical embodiment of the 
present invention includes a molded tray having an outwardly extending 
flange portion and a latch receiving keyhole opening, a molded lid having 
an outwardly extending flange portion which is larger and shaped similarly 
to the flange portion of the molded tray so as to fit over and around the 
flange portion of the molded tray, and a slide latch mechanism attached to 
the molded lid and designed for securing the lid to the flange portion of 
the molded tray by means of the latch-receiving opening. 
One object of the present invention is to provide an improved plastic 
autoclave enclosure. 
Related objects and advantages of the present invention will be apparent 
from the following description.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
For the purposes of promoting an understanding of the principles of the 
invention, reference will now be made to the embodiment illustrated in the 
drawings and specific language will be used to describe the same. It will 
nevertheless be understood that no limitation of the scope of the 
invention is thereby intended, such alterations and further modifications 
in the illustrated device, and such further applications of the principles 
of the invention as illustrated therein being contemplated as would 
normally occur to one skilled in the art to which the invention relates. 
Referring to FIGS. 1, 2, 3, 4 and 5 the plastic autoclave enclosure 20 
including tray 21 and lid 22 according to the Present invention is 
illustrated. The tray 21 is a molded, vacuum formed, integral and unitary 
member having a generally rectangular sidewall 23, base 24 and surrounding 
an outwardly extending rectangular flange 25 (see FIG ,6). Disposed on and 
as part of flange 25 are four raised protuberances 21a, one centered in 
each corner of flange 25. While flange 25 has a generally rectangular 
shape in its top plan orientation, the flange has an inverted U-shaped 
lateral cross section. The top surface 26 of flange 25 is wider at 
enclosure ends 27 and 28 than at or along the enclosure sides 29 and 30. 
This extra width along the enclosure ends provides a sufficient surface 
area for the placement of keyhole slots 31 and 32 each of which have an 
enlarged portion at one end and a more narrow slot extending therefrom. It 
is also to be noted that keyhole slots 31 and 32 have the same orientation 
such that the narrower slot portion extends from the enlarged opening in 
the same direction To lock the tray to the lid the slide latches are 
pulled toward the user, if the user is positioned on enclosure side 29. To 
release the lid, the slide latches are pushed toward side 30, in the 
direction of the enlarged opening in each keyhole slot. 
Protuberances 21a have a vacuum formed height of approximately 0.065 inches 
and when the lid 22 is closed onto the tray, these protuberances create a 
lid to tray separation. In order for the slide latches to operate to 
secure the lid to the tray, the lid must flex. This flexure induces more 
pressure on the latching members thereby reducing the necessity for 
holding tight tolerances in the latching components and the thickness of 
the lid and tray. The separation crevices which are left between the tray 
and lid provide additional passageways for sterilant during the 
autoclaving process. 
Vacuum formed into the base 24 of tray 21 are a pair of substantially 
parallel stiffening and support ribs 33 which additionally serve as feet 
for the enclosure. Ribs 33 raise base 24 off of whatever the supporting 
surface may be used and allows drainage of any moisture or condensation 
which is collected within enclosure 20. All of the inner and outer corners 
and corner edges of tray 21 and lid 22 are smooth and rounded except for 
the underside surfaces 36 (tray 21) and 37 (lid 22). The tray and lid are 
vacuum formed with a pressure flange which is then removed leaving 
surfaces 36 and 37. While surfaces 36 and 37 are smooth, there is not 
sufficient thickness in order to provide a large radiused or rounded 
surface. These surfaces are basically flat though any sharp edges are 
removed by deburring after the pressure flange is removed. The smooth and 
rounded corners and edges are readily fabricated as part of enclosure 20 
due to the fact that the tray and lid are vacuum formed out of a high 
temperature plastic. These smooth and rounded inner and outer corners and 
edges provide an enclosure which is easy and comfortable to handle and to 
use. The smooth surfaces and rounded edges will not puncture or tear any 
paper barrier wrapping. A plurality of steam holes 38 are drilled into the 
tray 21 and lid 22. Suitable materials for the tray 21 and lid 22 include 
"ULTEM-1000" offered by General Electric and "RADEL 5000" offered by 
Amoco. 
Lid 22 is arranged with an inset, raised frame portion 40 and integrally 
connected therewith a pair of substantially parallel ribs 41 and 42. These 
two ribs divide the top surface into three generally rectangular areas 
40a, 40b and 40c. The underside of frame portion 40 and ribs 41 and 42 
define an open channel network with all channel areas open and 
interconnected. This raised frame portion design in combination with the 
two ribs provides added strength and rigidity to lid 22. The lid is able 
to maintain its substantially flat configuration without warpage or 
distortion. This in turn assures that the outer lip 43 of lid 22 will fit 
closely down over and around the outer lip 44 of tray 21. 
Referring to FIG. 6A the edge offset (D) between the tray (surface 36) and 
lid (surface 37) is illustrated. In accordance with the present invention 
the lower edge 37 of the lid flange is trimmed to a dimensional height so 
as to be shorter than the tray lower edge 36. This construction enables 
any pick-up, lifting or handling forces to be transmitted to the tray 
flange and in effect not to the lid flange. The result is a lower or 
decreased likelihood that the tray contents will be dumped if the latches 
are inadvertently left open. 
The raised frame portion 40 is notched at ends 45 and 46 with molded relief 
areas 47 and 48, respectively. Riveted in position within areas 47 and 48 
are a pair of slide latches 49 (see FIG. 7). Each slide latch includes a 
metal frame 50, a convex spring clip 51, a convex slide 52 and shouldered 
collar 53 and cooperating screw 53a. The assembly of the shouldered collar 
and the screw creates pin-type member with an enlarged head. Frame 50 is 
riveted at opposite ends to the top surface of lid 22 and spring clip 51 
is riveted at one end to the underside surface lid 22 permitting necessary 
flexing of the spring. The rectangular slot 54 disposed in frame 50 is 
aligned with the oblong slot 55 in lid 22 and with the oblong slot 56 in 
clip 51. Slide 52 has a protruding extension on its underside which 
extends through slot 54 and slot 55. Shouldered collar 53 abuts up against 
extension 57 in order to establish a fixed clearance spacing for the head 
of screw 53a. This insures that the spring clip will not be flattened by 
over tightening or advancing of screw 53a. The enlarged head 58 of screw 
53a is disposed on the back side of spring clip 51 and the reduced 
diameter portion of collar 53 rides within the oblong slot 56. Frame 50 
includes side wings 50a and 50b which assist in guiding slide 52 and in 
turn in guiding extension 57 through slots 54 and 55. The entirety of the 
slide latch assembly in an exploded view form is illustrated in FIG. 7. 
By means of clamping pressure applied against the lid 22 onto tray 21 the 
convex shape of each clip 51 will flatten in a spring-biased manner 
allowing the enlarged head 58 of each pin 53a and the enlarged diameter 
portion of collar 53 to fit into the enlarged end opening of each 
corresponding keyhole slot 31 and 32. Then by pushing or pulling the 
slides 52 (note in the same direction), the enlarged heads 58 and enlarged 
diameter portions will be received and retained by the narrower portions 
of each keyhole slot. The spring-biased nature of clip 51 which is still 
flattened from its normal convex shape, provides a continuous spring force 
which securely holds the tray and lid combination together in a closed 
condition without allowing any movement, vibration or looseness to these 
two main members. This enables the tray and lid combination of enclosure 
20 to be secure and quiet. Even the action of the slide latch 49 is smooth 
and quiet and easily manipulated. By the user holding the tray and lid 
tightly together the clips 51 will be flattened and the convex slide can 
move almost effortlessly through the corresponding keyhole slots from the 
enlarged end which initially receives each of the heads 58 and enlarged 
diameter portions of the collars 53 into the narrower slot portion which 
securely holds the heads into position. Once each slide is pulled into its 
locking position the clamping force on the tray and lid which has been 
manually exerted can now be removed. This closing process is then reversed 
in order to open the enclosure. However, even if the tray and lid are not 
manually clamped together when manipulating the slot latches, they will 
still perform and function in the fashion described. There will simply be 
more force required because the pushing or pulling slide action will be 
required to flatten out each clip 51 as opposed to manually flattening 
those clips prior to moving the pins by holding the lid and tray together. 
However, even if the tray and lid are not manually clamped together the 
slide latch action will still be quiet and secure. The opposite ends of 
frame 50 are marked with the initials "OP" for open and "LK" for locked. 
Referring to FIG. 6 another feature of the present invention is 
illustrated. It is to be noted that ribs 33 are spaced-apart slightly 
wider than the spacing of ribs 41 and 42, though the clearance is still 
close. These two pairs of ribs are also substantially parallel to each 
other. Further, the length of ribs 33 is just slightly less than the 
length of areas 40a and 40c. These dimensional and positional 
relationships permit the tray to be stacked on top of the lid. While this 
stacked arrangement is not locked nor rigidly secured, the tray is clearly 
retained in the lid such that normal forces which may be exerted on one of 
the two stacked enclosures will not allow one enclosure to separate from 
the other enclosure. The base of the tray stacks down onto and within the 
top of the lid and creates a securely stacked combination. Forces that try 
to push or pull the tray in a horizontal plane will result in the ribs 33 
abutting up against either ribs 41 and 42 and/or the inside wall surface 
of frame portion 40. As a consequence of this design, a number of 
enclosures 20 can be stacked one on top of the other thereby providing a 
more convenient and efficient design over autoclave enclosures that are 
not stackable. 
While the invention has been illustrated and described in detail in the 
drawings and foregoing description, the same is to be considered as 
illustrative and not restrictive in character, it being understood that 
only the preferred embodiment has been shown and described and that all 
changes and modifications that come within the spirit of the invention are 
desired to be protected.