Abstract:
A sharp disposal assembly includes a receptacle, lid therefor and an unwinder having three flanges on each side of a slot opening in the lid. A substantially cubical compartment formed by the six flanges receives a needle-hub-safety shield unit in a loose non-binding immobilization which provides firm support to the unit during unwinding and yet precludes any hangup which might necessitate manual separation.

Description:
FIELD OF THE INVENTION 
     This invention relates to medical devices and more particularly relates to blood sampling devices and safe disposal thereof. 
     BACKGROUND OF THE INVENTION 
     Many medical articles used in hospitals and clinics are designed for one-time use. Articles which have sharp points, cutting edges and the like, are collectively known as sharps, and many disclosures of special equipment and procedures have been proposed to minimize the danger of injury such as needle sticks, to personnel involved in the use or disposal of these articles. Safe handling and disposal is particularly important, since a sharp is often used in a procedure, such as blood sampling, and as a result may be contaminated with a potentially infectious agent. 
     Many designs of disposal equipment for sharps have been proposed. Most include a storage container having a lid with locking closure features and several openings through the lid for access to the interior of the container. Often the sharp is affixed to a hub having threads mated to a tube holder, and it is conventional that one of the openings have structure associated therewith, known as the unwinder, for unthreading the sharp from the holder without any manual manipulation by the user. 
     Conventional unwinders operate by inserting a needle-hub member into the large end of a V-shaped opening and advancing the member toward the narrow end of the opening until ribs on the hub engage the wall of the unwinder. At this point, a twisting rotation of the needle holder causes the hub-needle member to drop off into the container. A common problem encountered with this design is hangup of the hub on the wall after removal of the holder, and occurs when the hub has engaged the wall too strongly. Typical sharps containers having an unwinder designed to unthread needle-hub members are disclosed in U.S. Pat. No. 4,375,849 to Hanifl and U.S. Pat. No. 5,415,315 to Ramiriz et al. respectively. An unwinder for double-ended needles is disclosed in U.S. Pat. No. 5,092,462 to Sagstetter et al. 
     While the above disclosures have advanced the art of sharps disposal, prior art unwinders do not perform well for disposal of sharps protected by a modern safety shield which prevents the unwinder from grasping the ribs. Thus, if a needle-hub-shield unit is advanced in a conventional unwinder, the shield must be tightly wedged between the opposite walls of the unwinder, often leading to severe hangup. Further, many reports from field use have described inadvertent premature raising-up of the holder by the technician before complete disengagement of the hub threads from the holder threads, a common occurrence also causing holdup and failure of the sharp to drop into the container. The present invention is directed to an unwinder design directed to overcoming these problems. 
     SUMMARY OF THE INVENTION 
     A sharps disposal assembly includes a receptacle, a lid for the receptacle and an unwinder having features for separating a needle-hub-member, preferably a needle-hub-safety shield unit, from a needle holder. The unwinder includes a slot or V-shaped opening bounded by an edge having flanges integral thereto which, along with a wedge-shaped segment of the lid, form a compartment in the opening which receives the safety shield in a loose non-binding fit. The assembly includes a large port opening for receiving large items such as blood collection sets, syringes and needle holders and the like. Preferred assemblies include closure flaps to cover the openings. 
     Because the unwinder defines a substantially cubical compartment loosely enclosing a conventional needle shield on three sides and the top, wedging cannot take place either during twisting or inadvertent pull-up, and no hangup can occur. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the sharps disposal assembly of the invention with the lid closure flaps open; 
     FIGS. 2 and 3 are transverse and longitudinal cross-sectional views taken along the lines  2 — 2  and  3 — 3  respectively of the assembly of FIG. 1 illustrating details of the unwinder; 
     FIG. 4 is a transverse cross-sectional view of the assembly of the invention taken along the line  2 — 2  thereof and viewed from the underside of the unwinder; 
     FIG. 5 is a side elevational view of an alternative embodiment of the invention; and 
     FIG. 6 is a side elevational view of an alternate embodiment of the invention. 
    
    
     DETAILED DESCRIPTION 
     While this invention is satisfied by embodiments in many different forms, there will herein be described in detail embodiments of the invention with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and is not intended to limit the invention to the embodiments illustrated and described. The scope of the invention will be measured by the appended claims and their equivalents. 
     The following description is directed to the preferred embodiment of the invention wherein the assembly is used to unwind threaded components, one of which is protected by a conventional needle shield, with the understanding that the new unwinder design may be used to disengage threads on any medical article to be discarded. 
     Adverting now to the drawings, wherein like elements are given the same reference number followed by a lower case letter in the various illustrations thereof, FIG. 1 illustrates a sharps disposal assembly  10  including a receptacle  12  and a lid  14 . Lid  14  has a large port opening  16 , a slot opening  18  tapered to form a “V” and a circular opening  20 . Port opening  16  may be of any suitable geometrical configuration, but for purpose of illustration is shown in the preferred rectangular shape. Tapered slot opening  18  extends from large end  22  to narrow end  24  wherein large end  22  is of sufficient size to accept a needle shield, and thus may preferably be about 10-15 mm across. Alternatively, the port and slot openings may be combined into single continuous opening. Circular opening  20  in lid  14  has insert  26  therein expressly dimensioned to engage a SAFETY-GARD™ tube holder, as sold by Becton, Dickinson and Company. Opening  20  and insert  26  are conventional features of prior art sharps disposal receptacles and are fully described in the aforementioned U.S. Pat. No. 5,092,462. 
     Flaps  27  are affixed to lid  14  by integral tabs  28  and have integral closure tabs  30  dimensioned for insertion into slots  32  of a plate portion  34  of lid  14  to cover the openings. 
     FIGS. 2 and 3 illustrate slot opening  18   a  to be bounded by an edge or wall  40 . Edge  40  abuts a post flange  42  which depends perpendicularly downward from edge  40 . A wedge flange  44  (shown in phantom) is an integral segment of a plate portion  34   a  of lid  14   a.  A substantially square wall flange  48  extends under wedge flange  44  and meets post flange  42  at a right angle. As best seen in FIG. 3, the underside of wedge flange  44   b,  post flange  42   b  and wall flange  48   b  define a recess  50 , which, together with a corresponding recess formed by the post, wall and wedge flanges on the other side of the slot opening, form a substantially cubical compartment for receiving a needle shield, as described below. Also shown in phantom in FIG. 2 is an optional support rib  52  extending from the back side of wall flange  48  to the underside of plate  34   b  to add rigidity to flange  48 . 
     In FIG. 4, the relationship of post flange  42   c,  wedge flange  44   c  and wall flange  48   c  to give recess  50   c  is shown as viewed toward the underside of lid  14   c.  FIG. 4 also shows support ribs  52   c  to be integral with plate  34   c.    
     In another embodiment of the invention, illustrated in FIG. 5, plate  34   d  may be sloped at an angle theta from the plane of lid  14   d.  Angle theta may be about 5-20°, preferably 10-15°, so that narrow unwinder end  24   d  is higher than large end  22   d.  This configuration causes a needle-hub unit, after unwinding, to slide down the slope and thereby aids in overcoming hangup. 
     In still another embodiment of the invention, illustrated in FIG. 6, the port and slot openings are combined into a single continuous opening  36 . 
     The new unwinder design of the invention greatly improves reliability and user safety in disposal of needles protected by needle shields. In use, the technician, grasping the needle holder, inserts the used needle shield unit into the large end of the slot opening with the top of the shield collar aligned slightly below the lid plate. The shield may then be advanced with any of its four faces, front, back, left or right, leading into the compartment formed by the three flanges until the technician feels contact of the shield with the post flange. At this point, the shield is properly positioned in the compartment by a loose fit, without touching any of the flanges, i.e., the compartment is dimensioned so that spaces are present along all sides of the shield. This design thus provides six areas of support from the flanges during twisting for effortless unwinding and assured drop into the receptacle because substantially all problems of hangup are overcome. 
     The assembly of the invention may be made of any suitable plastic, such as polyethylene, polypropylene and polyvinyl chloride. The lid with the unwinder elements is preferably made by conventional injection molding with integral construction wherein all of the parts are continuous with no seams therebetween.