Abstract:
A support base for a front-loading sterilizer includes a retractable shelf for staging items to be loaded into the sterilizer, and for drying and cooling items that are removed from the sterilizer. The retractable shelf includes a holding element characterized by periodically-spaced lateral troughs and crests. Items to be dried may be positioned on the crests so that ambient air may flow below the items for drying and condensate may drain into the troughs. The drying element may be fixed to or removable from the holding element. The support base may optionally and integrally include chassis members of the sterilizer.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to a support base and work surface used in conjunction with industrial apparatus. More particularly, the invention relates to a sterilizer support base having a retractable shelf.  
         BACKGROUND OF THE INVENTION  
         [0002]    Steam autoclaving is a well-known and reliable method used widely to sterilize media and lab equipment as well as to decontaminate infectious waste. Autoclaves introduce saturated steam within a pressurized chamber (for example, at pressures of 15 psi or more) in order to generate sufficient temperatures (for example, at or above 275 degrees Fahrenheit) to achieve sterilization. Heat produced by saturated steam at such temperatures is effective in damaging essential cellular structures of biological organisms present in the pressurized chamber, and with sufficient time, in killing such organisms.  
           [0003]    Items placed in autoclave chambers are subjected to pressurized steam. Care is required in removing these items after the autoclaving process has completed. The chamber must be depressurized before opening. Upon removal, water condensate may be present on the sterilized items and require evaporation and/or draining. Also, the sterilized items may be slippery and difficult to handle. Accordingly, it would be desirable to provide an area adjacent to the autoclave and appropriately configured for receiving and drying sterilized items as they are removed from the autoclave chamber.  
           [0004]    Devices for holding items placed within an autoclave are known in the art (for example, see U.S. Pat. No. 4,670,227, issued to Smith on Jun. 2, 1987). Specialized work surfaces have been developed for use with other appliances (for example, see U.S. Pat. No. 4,436,356, issued to Stelling on Mar. 13, 1984). However, to date, there does not appear to be disclosed a specialized work surface positioned adjacent to an autoclave for receiving and drying sterilized items as they are removed from the autoclave chamber.  
         SUMMARY OF THE INVENTION  
         [0005]    A convenient work surface both for staging items to be placed in an autoclave for sterilizing and for retaining items removed from an autoclave for staging, cooling or drying is provided by a novel autoclave support base. The support base is equally well suited for application to other types of sterilizers such as dry-heat and chemical vapor sterilizers.  
           [0006]    The support base comprises a base housing having a top surface for receiving and supporting the autoclave, and left and right support members respectively and downwardly attached in proximity to left and right opposing edges of the top surface, such that the top surface and left and right support members define a cavity in the base housing. A holding shelf is slidably mounted within the cavity in the base housing.  
           [0007]    The holding shelf includes a holding surface depressedly positioned with respect to front, rear, left and right edges of the holding shelf so that surfaces defined between the front, rear, left and right edges of the holding shelf and the holding surface act to confine items placed on the holding surface. The holding surface may be pitched toward one or more perforations in the holding surface to facilitate drainage.  
           [0008]    In an illustrative embodiment of the present invention, a holding element is positioned within the front, rear, left and right edges of the holding shelf and supported by the holding surface for holding the staged or removed items. A drying surface of the holding element has a plurality of periodically and laterally spaced troughs and crests, each crest defining an elevated positioning surface for holding drying items in order to promote a flow of ambient air under the items. The holding element may be fixed to the holding shelf, or may be removable. These crests may include indentations for positioning items on the crests of the holding element.  
           [0009]    In another illustrative embodiment of the present invention, the support base includes at least one securing panel upwardly attached at an edge of the top surface for fastening to the autoclave. The at least one securing panel may include apertures for permitting access to the autoclave chamber and controls, and for fastening autoclave door hinge and catch hardware in a manner that effectively secures the securing panel to the autoclave. Preferably, the at least one securing panel comprises a chassis of the autoclave for holding components of the autoclave together in an assembly.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    A more complete understanding of the invention may be obtained by reading the following description of specific illustrative embodiments of the invention in conjunction with the appended drawing in which:  
         [0011]    [0011]FIG. 1 provides a perspective view of an inventive autoclave support base, with the holding shelf extended and as seen from a right front side;  
         [0012]    [0012]FIG. 2 provides a perspective view of the support base of FIG. 1 as seen from a right rear side, and illustrating a first embodiment of a holding element positioned in the holding shelf;  
         [0013]    [0013]FIG. 3 provides a perspective view of the support base of FIG. 1 as seen from the right front side, further depicting placement of an autoclave on the top surface of the support base;  
         [0014]    [0014]FIG. 4 provides a front view of the support base of FIG. 1 further depicting placement of an autoclave on the top surface;  
         [0015]    [0015]FIG. 5 illustrates an element of the present invention including a spring catch mechanism for retaining the holding shelf of the support base in a retracted position;  
         [0016]    FIGS.  6 ( a ),  6 ( b ) present an alternative shelf and holding element; and  
         [0017]    [0017]FIG. 7 shows an alternative embodiment of the support base having an integral autoclave chassis defined by one or more base housing securing panels. 
     
    
       [0018]    In the various figures, like reference numerals wherever possible designate like or similar elements of the invention.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    The following detailed description includes a description of the best mode or modes of the invention presently contemplated. Such description is not intended to be understood in a limiting sense, but to be an example of the invention presented solely for illustration thereof, and by reference to which in connection with the following description and the accompanying drawing one skilled in the art may be advised of the advantages and construction of the invention. For example, while the description is made with reference to autoclave sterilizers, application to other types of sterilizers, such as dry-heat and chemical vapor sterilizers, is fully contemplated within the scope of the invention.  
         [0020]    A right front perspective view of an inventive autoclave support base  100  is shown in FIG. 1. Support base  100  includes a base housing  110  and a holding shelf  130 , the holding shelf  130  being slidably mounted in a cavity defined by a top surface  111 , a left support member  112  and a right support member  113  of the base housing  110 . Holding shelf  130  further includes a gripping surface  138   a , which flows downwardly from a front edge  138  of holding shelf  130 . Gripping surface  138   a  provides a convenient handle for extending and retracting holding shelf  130 .  
         [0021]    Base housing  110  and holding shelf  130  may each be formed in a conventional manner from a single piece of sheet steel. Alternatively, base housing  110  and holding shelf  130  may each be formed as conventional plastic moldings.  
         [0022]    Although left and right support members  112 ,  113  are shown in FIG. 1 as extending continuously along left and right edges of top surface  11 , one skilled in the art will readily recognize that support members may be configured in a variety of alternative ways to support top surface  111 . For example, support members  112 ,  113  may be alternatively configured as legs positioned at left and right or front and back edges of top surface  111 . The legs may be positioned inwardly from rather than directly at the left and right or front and back edges.  
         [0023]    [0023]FIG. 2 shows a right rear perspective view of the support base  100  of FIG. 1. As illustrated in FIG. 2, base housing  110  further includes a rear support member  114  which is attached to a rear edge  124  of the base housing  110 . Rear support member  114  is similar in shape and size to legs  112   a ,  113   a  earlier described. When placed upon a supporting surface (not shown), rear support member  114  provides additional rigidity to the top surface  111  of base housing  110 . Optionally, rear support member  114  may further include a base flange  115 , which together with support member flanges  116  provides an increased contact area between the base housing  110  and the supporting surface. Optionally, base flange  115  and support member flanges  116  may each contain one or more apertures  125  for fixedly attaching base housing  110  to the supporting surface using conventional fasteners.  
         [0024]    Holding shelf  130  of FIG. 2 includes a holding surface  132  (partially obscured) which is depressedly positioned with respect to holding shelf edges  138 . Surfaces  131  defined between edges  138  and holding surface  132  are approximately perpendicular to holding surface  132  and serve to confine items placed on holding surface  132  in proximity to one or more edges  138 .  
         [0025]    As shown in FIG. 2, holding shelf  130  may also optionally include a holding element  139 , which is positioned near edges  138  and supported by holding surface  132 . Holding element  139  may be fixedly fastened to holding surface  132  by any of a variety of fastening techniques, or alternatively, may be integrally formed as part of holding shelf  130 .  
         [0026]    In FIG. 2, holding element  139  has a drying surface  150  which is further defined by a plurality of lateral troughs  133  and lateral crests  134 . Items that have been sterilized in the autoclave, for example, may be positioned to rest across lateral crests  134  in order to promote air flow through lateral troughs  133  for improved drying and cooling of the sterilized items. Alternatively, lateral troughs  133  may be used to organize and hold some of the drying items (for example, such as dental picks and other slender instruments). Condensate that forms on the drying items may effectively drain into lateral troughs  133  to facilitate drying.  
         [0027]    In order to more effectively remove condensate from the holding element  139 , lateral troughs  133  may be pitched such that condensate drains to holding surface  132 . Holding surface  132  may also be pitched so that this condensate may be led to a perforation in holding surface  132  for draining.  
         [0028]    [0028]FIG. 3 illustrates an embodiment of the present invention in which top surface  111  of the support base  100  supports an autoclave  200 . Autoclave  200  is, by way of example, a front-loading unit having a sterilizing chamber  220  and a sealing door  210 . Holding shelf  130  of the support base  100  is conveniently positioned for loading items in and unloading items out of sterilizing chamber  220 .  
         [0029]    [0029]FIG. 4 provides a front view of the embodiment of FIG. 3. FIG. 4 illustrates conventional pull-out slides (sometimes referred to as drawer slides) that include a left track  117  fastened to left support member  112  and a right track  118  fastened to right support member  113 . Glide wheel assemblies  119  and  120  are respectively retained by the tracks  117  and  118 , which are fixedly attached to side surfaces  136  of holding shelf  130 . Glide wheel assemblies  119  and  120  move within tracks  117  and  118  in order for holding shelf  130  to move from a retracted position mostly within the base housing  110  to an extended position mostly outside base housing  110 . The extended position of holding shelf  130  is illustrated in FIGS.  1 - 3 . As illustrated in FIG. 1, for example, retention stops  123  may be fitted at front ends of tracks  117  and  118  in order to prevent holding shelf  130  from being over-extended from base housing  110 . Retention stops  123  (not shown) may also be optionally fitted at the rear ends of tracks  117  and  118  in order to more effectively position holding shelf  130  in the retracted position. Such track and glide assemblies are well-known in the art, and are readily available (for example, as part number C2132-20DOP from Accuride International Inc. of Sante Fe Springs, Calif.).  
         [0030]    [0030]FIG. 4 also illustrates how autoclave  200  may be secured to base housing  110 . Autoclave  200  includes a plurality of feet  230 , each of which contains a threaded insert  231 . Top surface  111  of base housing  110  included a number of apertures  121  whose centerlines are positioned to align with centerlines of the threaded inserts  231  when autoclave  200  is appropriately positioned on top surface  111 . Once positioned on top surface  111 , autoclave  200  may be secured by inserting bolts  240  through the apertures  121  to mate with threaded inserts  231 , and then appropriately tightening the bolts  240  until autoclave  200  is secured to top surface  111 . Autoclave  200  may be secured to base housing  110  by a variety of other equivalent means. For example, tabs may be punched in top surface  111  to mate with slots in a front pair of autoclave feet  230 , so that only a rear pair of autoclave feet  230  are fastened by inserting bolts  240  through a matching pair of rear apertures  121 . Alternatively, lateral movement of autoclave  200  may be limited by providing indented or embossed regions in top surface  111  for restraining feet  230  of autoclave  200 .  
         [0031]    As earlier noted, base flange  115  and support member flanges  116  may each contain one or more apertures  125  for fixedly attaching base housing  110  to a supporting surface using conventional fasteners. Alternatively, and as illustrated in FIG. 4, base flange  115  and support member flanges  116  may be fitted with friction pads  151  to reduce lateral movement between flanges  115 ,  116  and the supporting surface. Friction pads  151  may be adhesively or mechanically fastened to flanges  115 ,  116 , and may be fabricated from a variety of suitable materials including rubber and cork. As an additional alternative, flanges  115 ,  116  may optionally be fitted with vertically-adjustable feet incorporating pads  151 . Such adjustable feet are well-known in the art, and provide an advantage in stabilizing the autoclave unit on an uneven work surface.  
         [0032]    [0032]FIG. 5 presents an enlarged cross-sectional view taken near the front edge of support base  100  illustrated in FIG. 4. As shown in FIG. 5, a spring catch  140  is inserted through aperture  137  to be retained in side surface  136  of holding shelf  130  by retaining washers  142 . Retaining washers  142  are affixed to spring catch  140  by any of a variety of conventional means.  
         [0033]    When holding shelf  130  is retracted within base housing  110 , force applied by spring  141  causes spring catch  140  to extend such that a distal end  144  of spring catch  140  is secured behind retaining tab  122  in left support member  112 . In this position, holding shelf  130  is secured to remain in a retracted position within base housing  110 . When it is desired to extract holding shelf  130 , disengaging arm  143  may be manipulated to compress spring  141 , moving spring catch  140  to a position where distal end  144  is no longer captive behind retaining tab  122 . In this catch position, holding shelf  130  may be easily extracted from base housing  130 .  
         [0034]    It should be noted that retaining tab  122  may be, for example, punched from left support member  112  such that a front edge  126  of retaining tab  122  is coplanar with an inner surface of left support member  112 , where front edge  126  is positioned outward from retaining edge  127 . In this configuration, a cam surface  128  defined by edges  126 ,  127  acts to compress spring  141  and move catching spring  140  toward side surface  136  when force is applied to return holding shelf  130  to its retracted position. By such means, distal end  144  may be automatically moved behind retaining tab  122  without manually operating disengaging arm  143 .  
         [0035]    Various other mechanisms may be employed for retaining holding shelf  130  within base housing  110 . For example, detents (not shown) may be incorporated in a lower portion of track  117 , such that glide wheels from glide wheel assemblies  119  may be moved vertically against gravity force and horizontally rearward to rest behind and be retained by the detents. Retained glide wheels may then be released by moving the wheels vertically against gravity force and horizontally forward from the detents. Such gravity catches are well-known in the art, and are available, for example, in drawer slide part number D2132-20D from Accuride International Inc. Alternatively, conventional magnetic catches may be employed to secure holding shelf  130  in a retracted position within base housing  110 . Catches may also be positioned to retain holding shelf  130  at one or more intermediate positions of extension from base housing  130 .  
         [0036]    FIGS.  6 ( a ),  6 ( b ) illustrate an alternative holding element  139   a  and holding shelf  130   a  for support base  100 . Holding element  139   a  of FIG. 6( a ) is positioned in holding shelf  130   a , which extends from base housing  110 . Lateral crests  134  of holding element  139   a  are dimpled to include regularly-spaced indentations  134   a . Indentations  134   a  provide a means for positioning items on crests  134  for drying. This means will be particularly useful, for example, in positioning thin, axially-oriented items such as dental instruments on the lateral crests.  
         [0037]    As further illustrated in FIG. 6( a ), holding shelf  130   a  includes cavity  138   b  near a right side of front edge  138 . Cavity  138   b  maybe used to hold small items not easily positioned on crests  134  for drying. Alternatively, cavity  138   b  may be used as an additional grip for extending and retracting holding shelf  130   a.    
         [0038]    Referring to FIGS.  2 ,  6 ( a ) and  6 ( b ), holding elements  139 ,  139   a  may be fashioned from a variety of materials, including sheet steel and molded plastic, and may be either removably or fixedly mounted within holding shelves  130 ,  130   a , respectively. Holding elements  139 ,  139   a  may also optionally be integrally formed with holding shelves  130 ,  130   a.    
         [0039]    [0039]FIG. 6( b ) presents a top view of the holding element  139   a  positioned in holding shelf  130   a  of base housing  110 . Perforations  135  are located along a bottom portion of channels  145 ,  146 , respectively located at left and right edges  147   a ,  147   b  of holding element  139   a . Channels  145 ,  146  are positioned to receive condensate drainage from holding element  139   a , which may be facilitated, for example, by pitching lateral troughs from centerline  147  downward towards channels  145 ,  146 . Perforations  135  provide a means for draining condensate received by channels  145 ,  146 .  
         [0040]    Alternatively, in lieu of perforations  135 , channel  145  may be pitched downwards toward perforation  135 ( a ), which is positioned in channel extension  145   a  near a front edge of holding shelf  130   a . This alternative configuration provides the advantage of positioning condensate drainage from holding shelf  130   a  near the front edge of the shelf where it can be more easily and confinedly dispersed. In this configuration, for example, channel  146  may be omitted, and lateral troughs  133  may be pitched downward from right edge  147   b  of holding element  139   a  toward channel  145 .  
         [0041]    [0041]FIG. 7 presents a perspective view of a second base housing embodiment  110   a . In base housing  110   a , securing panels  160 ,  161  extend upwardly from top and rear edges  11   a ,  111   b  of top surface  111 , respectively. Securing panels  160 ,  161  effectively define an internal chassis for autoclave  200 . In other words, the internal and external components of autoclave  200  may be assembled to securing panels  160 ,  161  so that base housing  110   a  becomes an integral part of autoclave  200 .  
         [0042]    A illustrated in FIG. 7, front securing panel  160  includes autoclave chamber access aperture  162   a  to permit access to the autoclave chamber  220  of FIG. 2. In addition, hinge mount apertures  162   a  and latch mount apertures  162   b  respectively provide mounting points for hinge and latch hardware associated with autoclave  200 . Access apertures  163   a ,  163   b  provide access for controls on the front panel of autoclave unit  200 . Access aperture  163   c  may be provided on rear securing panel  161  for a similar purpose.  
         [0043]    Gusset plates  164  are optionally attached at right and left edges  160   c ,  160   d  of front securing panel  160  and at right and left edges  111   c ,  111   d  of top surface  111  to make securing panel  160  more rigid. Gusset plates  164  may also be optionally attached at right and left edges  161   c ,  161   d  of rear securing panel  161  and right and left edges  111   c ,  111   d  of top surface  111 . Although base housing  110   a  of FIG. 7 is illustrated with front securing panel  160  and rear securing panel  161 , embodiments including only one of the front and rear panels  160 ,  161 , as well as embodiments including one or more side panels attached at side edges  111   c ,  111   d , are fully contemplated and within the scope of the present invention.  
         [0044]    It should also be noted that, securing panels  160 ,  161  may be alternatively configured as an external chassis for confining autoclave  200  to top surface  111  of FIG. 7. In this alternative configuration, securing panels  160 ,  161  may be fastened to components affixed to the exterior of autoclave  200  (for example, fastening external hinge and latch hardware respectively through apertures  162   a ,  162   b  of securing panel  160 .) In addition, gusset plates  164  and securing panels  160 ,  161  may be positioned in close proximity to exterior surfaces of autoclave  200  in order to restrict lateral movement of autoclave  200  on top surface  111 . Other means (for example, as described in conjunction with FIG. 4) may be additionally employed to retain autoclave  200  against top surface  111 .  
         [0045]    [0045]FIG. 7 also illustrates an alternate embodiment for support members  112 ,  113  of FIG. 1. In FIG. 7, support members  112   a ,  112   b  and support members  113   a ,  113   b  each form an L-shaped member  112 ,  113  for supporting top surface  111 . Members  112   b ,  113   b  are respectively attached at edges  111   d ,  111   c  and to bottom surface  111   e  so that members  112   a ,  113   a  are vertically positioned with respect to top surface  111 , and inwardly positioned with respect to edges  111   d ,  111   c . Members  112   a ,  113   a  are also parallel to edges  111   c ,  11   d , and to each other.  
         [0046]    Apertures  165  in members  112   a ,  113   a  may be used to fasten tracks  117 ,  118  (not shown) on interior surfaces of members  112   a ,  113   a . Alternatively, tracks  117 ,  118  may be fastened to members  112   a ,  113   a  by a variety of other means including spot welding and gluing. Apertures  166  may be used for securing members  112 ,  113  to bottom surface  111   e . Again, alternative fastening means such as spot welding and gluing may be used. Although members  112 ,  113  may simply be fastened to edges  111   d ,  111   c , for example, as a folded construction from a single piece of sheet metal, it may be advantageous to provide additional fastening between members  112   b ,  113   b  and bottom surface  111   e  for added strength. If such additional fastening means are employed, apertures  166  may be alternatively used, for example, to mount adjustable feet for positioning base housing  110   a  on an uneven work surface. As depicted, base housing  110   a  may be fashioned from one or more pieces of folded sheet steel using conventional assembly methods. For strength and corrosion resistance, stainless steel is a preferred material for base housings  110 ,  110   a , although molded plastics and other materials may be employed as well.  
         [0047]    While the present invention has been described at some length and with some particularity with respect to the several described embodiments, it is not intended that it should be limited to any such particulars or embodiments or any particular embodiment, but it is to be construed with references to the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and, therefore, to effectively encompass the intended scope of the invention.