Abstract:
A sterilizable, stackable medical/dental instrument casette is formed of sterilization heat resistant plastic. A cover of the casette is closable, openable and separable from a tray of the casette. The tray is stackable on the cover, or other identical casette covers. Flexible, movable rails define compartments within the casette, and support and separate instruments in the casette. The cover is securely latchable to the tray.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to medical/dental instrument trays, and more particularly to a dental instrument casette. 
     In the past, dental instruments were sterilized while loose, and selected during operations from an array of instruments, by name. In the more recent past, dental instruments have been sterilized while loose, and organized before operations in trays, to be taken from the trays and used in the sequence in which placed in the trays. Most recently, dental instruments have been organized in trays first, and then sterilized and used. However, the trays most recently in use have been reinforced wire mesh baskets. They have been costly, unstackable, with hinged lips difficult to keep open, subject to rust, discoloration, breakage, and debris entrapment. 
     SUMMARY OF THE INVENTION 
     The object of the inventors in making this invention was to achieve a medical/dental instrument casette with the advantages of past trays, without the disadvantages. Another object was to provide a dental instrument casette which was rugged, versatile, safe to handle, inexpensive, stackable in number and over its own top, and pleasing of appearance. 
     Thus, in a principal aspect, the present invention is a sterilizable, stackable, medical/dental instrument casette. The casette comprises, first, a tray of sterilization heat resistant material having a plurality of sterilization openings, and a cover of sterilization heat resistant material having a plurality of sterilization openings. Hinge means is on the cover and the tray for releasably hingeably joining the cover to the tray. The cover and tray are thereby separable and hingedly movable to and from open and closed positions. Latch means of sterilization heat resistant material is on the cover and tray for releasably latching the cover to the tray in the closed position. Instrument retaining means of sterilization heat resistant material is also on the cover and tray for releasably retaining dental instruments within the closed cover and tray remote from contact, in at least a first fixed arrangement and in both the open and closed positions of the cover and tray. Finally, stacking means of sterilization heat resistant material is on the cover and tray for stacking the tray over the cover while separated therefrom. 
     Thus, the medical/dental instruments and casette may be repeatedly cycled through a process of placement of the instruments in the casette in the fixed arrangement, sterilization of the instruments and closed casette together, use of the sterilized instruments, and return of the instruments to the casette. 
     These and other aspects, objects and advantages of the invention are provided in a detailed description of the preferred embodiment of the invention, which follows a brief description of the drawing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The preferred embodiment of the invention is the casette shown in the accompanying drawing of three sheets and nine figures or FIGS. The figures are as follows: 
     FIG. 1 is a first perspective view of the preferred casette, closed; 
     FIG. 2 is a second perspective view of the preferred casette, open to reveal internal features and representative contents; 
     FIG. 3 is a plan view of the casette cover, from the underside; 
     FIG. 4 is a first section view of the cover, taken along line 4--4 of FIG. 3; 
     FIG. 5 is a second section view of the cover, taken along line 5--5 of FIG. 3; 
     FIG. 6 is a plan view of the casette tray, from above; 
     FIG. 7 is a first section view of the casette tray, taken from along line 7--7 of FIG. 6; 
     FIG. 8 is a second section view of the casette tray, taken along line 8--8 of FIG. 6; and 
     FIG. 9 is a partial, elevation view of the casette tray, showing a latch piece. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, the preferred embodiment of the invention is a sterilizable, stackable, medical/dental instrument casette 10. The casette 10 is useful for repeatedly cycling through a process of use and autoclave sterilization in which instruments such as instrument 12 (FIG. 2) are placed and kept in loose and fixed arrangements in the casette. The instruments are removed from the casette only for use, repair or replacement. The casette is adaptable to a plurality of pre-selected, fixed arrangements of instruments, as will be described. 
     A rectangular tray 14 of the casette has a bottom 16 (FIG. 6) and four tray sidewalls 18, 20, 22, 24 defining a tray interior 26 and a tray exterior 28. The bottom and tray sidewalls are formed of sterilization heat resistant plastic, and are perforated substantially completely with a plurality of sterilization openings 30 from the tray exterior 28 (FIG. 2) to the tray interior 26. 
     A rectangular cover 32 has a top 34 (FIG. 3) and four cover sidewalls 36, 38, 40, 42. The top and cover sidewalls define a cover interior 44 and a cover exterior 46. The top and cover sidewalls are formed of sterilization heat resistant plastic. They are perforated substantially completely with a plurality of the sterilization openings 30 from the cover exterior 46 (FIG. 2) to the cover interior 44. 
     Hinges 48 (FIG. 2) on the first tray sidewall 18 and the first cover sidewall 36 releasably, hingeably join the first cover sidewall 36 to the first tray sidewall 18 and thereby the cover 32 to the tray 14. The cover 32 and tray 14 are thereby hingedly movable relative to each other about the hinges 48 to and from open and closed positions. The cover 32 and tray 14 are also separable from each other when the top of the cover and the bottom of the tray are substantially perpendicular, or just past true perpendicularity. 
     The hinges include hinge pins 49 (FIGS. 2,6) on the tray 10, and arcuate hinge flanges 50 (FIGS. 2,3) on the cover 32. The hinge flanges 50 engage and rotate about the hinge pins 49 to and from the closed position and open position. With the cover moved from the closed position just past perpendicularity with the tray, a chamfered or angled first cover sidewall ledge 52 (FIGS. 2,3) along the sidewall 36 rests against a chamfered first tray sidewall ledge 54 (FIG. 6) along the tray sidewall 18. The flanges 50 hold the cover 32 on the tray 14 in this position, unless the cover is lifted upward in a direction generally parallel to the plane of the first tray ledge 54. When the cover is so lifted, the hinge pins 49 disengage from the hinge flanges 50, releasing the cover 32 from the tray 14. The cover 32 is returned to the tray by opposite movement. The hinges 48 thus constitute a form of hinge means on the cover and the tray for releasably hingeably joining the cover to the tray, the cover and tray thereby being separable and being hingedly movable to and from open and closed positions. 
     As best shown in FIG. 2, the hinge pins 49 and flanges 50 are recessed inward of the common plane defined by the sidewalls 36, 18 when co-planar, in the closed position of the tray and cover. With the recess toward the tray and cover interiors, the common sidewall plane provides a back surface for the stable, upright placement of the casette 10. 
     The hinges are formed of sterilization heat resistant plastic. 
     Latches 56 (FIG. 1) are on the second tray sidewall 20 opposite the first tray sidewall 18 and on the second cover sidewall 38 opposite the first cover sidewall 36. The latches 56 releasably latch the second cover sidewall to the second tray sidewall and thereby the cover to the tray in the closed position. The latches are formed of sterilization heat resistant plastic. 
     The latches 56 include cross-sectionally triangular latch pieces 58 (FIGS. 2,8,9) slidably mounted in slots 60 (FIG. 6) in a second, chamfered, tray ledge 62. The latch pieces 58 include latch keys 64 which operatively cooperate with further slots 66 in a second, chamfered, cover ledge 68. The latch pieces 58 are slidable to and from latching and unlatching positions. In the latching positions, the latch keys 64 extend through the slots 66, and behind portions of the ledge 68 adjacent the slots 66. In the unlatching positions, the latch keys align with the slots 66 and do not extend behind portions of the ledge 68. Thus, the latches 56 constitute one form of a latch means on the cover and tray for releasably latching the cover to the tray in the closed positon. 
     The latch pieces 58 are recessed inward of the common plane defined by the sidewalls 38, 20 when co-planar, in the closed position of the tray and cover. The common sidewall plane provides a front surface for stable, upright placement of the casette 10. 
     The sidewalls 22, 40 and 24,42 further provide planar side surfaces for stable, upright placement of the casette. 
     Instrument compartment rails such as rails 70,72 (FIG. 2) are removably fastened to the cover sidewalls within the cover interior and the tray sidewalls within the tray interior, at corresponding locations. The compartment rails thereby define such instrument compartments as may be preferred within the closed casette. The compartment rails are also formed of sterilization heat resistant plastic. 
     Instrument locating and retaining rails such as rails 74, 76, 78 (FIG. 2) are removably fastened to the cover sidewalls within the cover interior and the tray sidewalls within the tray interior, and within such instrument compartments as desired. The locating and retaining rails include thereon spaced instrument holders such as nesting recess 80 adapted to snugly, releasably locate and hold instruments in spaced relation to each other away from the tray exterior, away from the cover exterior, and within the instrument compartments. The locating and retaining rails 74, 76 are further formed of sterilization heat resistant plastic. 
     All the rails are laterally flexible, to be bowed for insertion in the casette 10. Each rail, such as rail 78, has ends with tabs, such as tab 82, of reduced cross section. Each tab is adapted to fit within tabs slots such as slot 84. The tab slots are spaced about all the tray and cover sidewalls, for placement of the rails transversely as shown, or for placement of longer rails longitudinally of the casette. The rails and tab slots thus constitute one form of an instrument retaining means on the cover and tray for reasonably retaining dental instruments within the closed cover and tray remote from contact, in at least a first fixed arrangement in both the open and closed positions of the cover and tray. The rail 78, unlike the other rails, includes a soft, flexible, heat resistant surround silicone over an internal bar. The surround is feathered, or partially, transversely, split in a closely spaced pattern of a plurality of slits, to resiliently press the instruments against the rails 74, 76. 
     Stacking feet such as foot 86 (FIG. 8) protrude from the tray bottom 16. Stacking feet receptors such as receptor 88 (FIG. 3) are recessed in the cover top 34 corresponding to the stacking feet. The feet and receptors cooperate such that the tray 14 is placeable upon and fixedly supportable atop the cover 32. As desired, the tray of one casette may be stacked atop the cover of another casette, or atop its own cover. A plurality of the casettes may be stacked, or a cover of a single casette simply placed under the casette tray to be out of the way, and save counter space. The feet and receptors thus constitute one form of a stacking means on the cover and tray for stacking the tray over the cover while separated therefrom. 
     As most preferred, the casette 10, except the silicone of the rail 78, is fully formed of polysulfone. Also as most preferred, the tray 14 and cover 32 are each molded in a single molding step, resulting in complete units of the tray and cover. A single cavity mold with interchangeable inserts for the hinge components is used for both the tray and cover. The latch pieces 58 are forced through the slots 60 when the tray ledge 68 is flexible, during molding of the tray 14. Ribs such as a rib 90 (FIG. 2) crisscross the tray bottom 16 and cover top 34 alongside and between the slots 30 to strengthen the cover 32 and tray 14. All internal and external corners of the casette 10 are rounded, for pleasing appearance and safety of usage. No closed-bottom recess, closed-bottom slot or other closed-bottom opening exists in the casette 10. As an example, a recess 92 (FIG. 8) is formed under the ledge 68. The recess 92 is open, not closed, along the bottom 16 of the tray 14. Contaminant entrapment is thereby avoided. Also, with the recess 92, breakage of a latch piece 58 does not result in entrapment of any broken remnants of the piece 58. The casette 10 can be stacked with other casettes in horizontal or vertical stacks, in any desired orientation of the casetttes. The casettes may be loaded with instruments and repeatedly sterilized and used, with the instruments thereby always efficiently arranged. Sterilization may be accomplished by means of autoclave, dry heat, and other suitable sterilization means. 
     The preferred embodiment is now described. If desired, features of the preferred embodiment may be varied. As an example, the hinge components may be closely toleranced such that the cover, if pivoted in relation to the tray past perpendicularity, will cam off the tray, without needing to be lifted off. To particularly point out and distinctly claim the subject matter regarded as invention, the following claims conclude this specification.