Patent Publication Number: US-2005133512-A1

Title: Packing box for laboratory articles

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a packing box for laboratory articles with a body which has been produced from plastic material with a peripheral jacket and a carrier plate which is provided with insertion openings for the laboratory articles. Laboratory articles of the pertinent type are especially laboratory articles which are arranged in a grid shape, such as pipette tips and reaction vessels.  
      Packing boxes for laboratory articles of the type under consideration, especially therefore for pipette tips, have been known for decades and used millions of times.  
      2. Description of Related Art  
      The packing box for pipette tips underlying the invention (U.S. DES. 271,239) can be produced especially economically and easily when manufactured of a plastic material. The body in the shape of an inverted trough has a slightly conically shaped jacket of plastic material and a carrier plate which is provided with insertion openings for pipette tips, which is likewise injected from plastic, and which on the top is interchangeably inserted into the jacket of plastic material, at the same time stiffening it. A cover of transparent plastic material, likewise with a slightly conically shaped jacket, allows the pipette tips held on the carrier plate of the body by the insertion openings to be recognized from the outside.  
      The inside of this packing box has a bottom which is inserted from underneath, which is pressed into the conical jacket, and is positioned and fixed on a peripheral step from the inside/underneath. This arrangement of the bottom within the body yields high stiffness of the jacket, and with the carrier plate inserted, of the body as a whole due to the box profile which is implemented in this way. Because the bottom is countersunk in the interior of the body, the packing box stands securely and stably on the peripheral edge of the body.  
      The above explained known packing box for pipette tips is generally made of a plastic material which can be autoclaved and is designed and suited for repeated used. For this purpose, the carrier plate, as soon as all the pipette tips which are held in it have been used up, is replaced by a carrier plate of a refill unit. These refill units are also known in the most varied embodiments (published European Patent Application EP 0 339 557 A2 and U.S. Pat. No. 3,937,322).  
      Moreover, it is inherently known in the area of packing boxes of the type under consideration that the cover of this packing box is made not to slip on, but to have a pivoting capacity and to be provided with a pressure closure (published International Patent Application WO 00/29113 A1).  
      It has been found that the initially explained packing box which is known from the prior art and which underlies the invention engenders a comparatively high cost in terms of production engineering. Altogether four plastic injection molded parts which are separate from one another must be produced, specifically the jacket, the carrier plate, the bottom and the cover. When the required tolerances are observed, especially with consideration of the capacity of the packing box which is intended for repeated use to be autoclaved, the production costs are considerable, as before. Last, but not least, the wall thickness of the conically shaped jacket of the body must be so great that it has sufficient bending stiffness with consideration of the stiffening function of the inserted bottom and is not warped especially when being autoclaved. This requires a corresponding wall thickness of the plastic material.  
     SUMMARY OF THE INVENTION  
      The primary object of the present invention is to further simplify and especially configure the above explained, known packing box for laboratory articles in terms of production engineering such that it can also be economically used especially as a disposable packing box.  
      The aforementioned object is achieved in a packing box with the features of the invention by which the carrier plate is produced in one piece with the jacket of the body, especially injected so that, overall, the body is made in the shape of an inverted trough. By means of this measure the body comprised of the jacket and the carrier plate acquires high inherent stiffness from the housing outward since such a box profile which is open on one side is implemented in one piece. Add to this, then, the additional stiffening action of the bottom which completely closes this box profile on the still open side. The result includes smaller wall thicknesses for the jacket in any case, preferably also the bottom and/or the carrier plate.  
      Overall, the packing box of the invention is especially suited as a disposable box. The somewhat higher material use compared to the known re-usable boxes is compensated by savings in outfitting in the production process and in handling by the laboratory worker. The overall business costs of a packing box which is configured in accordance with the invention, in use as a disposable box, can be less than in a reusable system as a result.  
      If the packing box of the invention is intended to be used only as a disposable box, the wall thickness of the plastic materials at all points can be further reduced because autoclaving is not necessary. The warping of the plastic material which occurs at high temperatures in the autoclave need not be feared in this case.  
      As already explained above, laboratory equipment of the type for which the packing box of the invention is intended and suited, includes, first of all, not only laboratory devices which are arranged in a grid and quite especially pipette tips, but also reaction vessels of glass, plastic, or other materials.  
      There are now various possibilities for advantageously embodying and developing the teaching of the invention and developments of the invention are described in detail below with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows in a perspective view of an especially preferred embodiment of a packing box in accordance with the invention which, in this case, is for use with pipette tips,  
       FIG. 2  shows the packing box from  FIG. 1  provided with a row of pipette tips and with the cover open,  
       FIG. 3  is a top plan view the packing box from  FIG. 2  with the cover closed,  
       FIG. 4  is a sectional view taken along line IV-IV in  FIG. 3 ,  
       FIG. 5  shows the packing box from  FIG. 2  in a perspective view obliquely from underneath, and  
       FIG. 6  is a sectional view of the area of a film hinge with which the cover is coupled to the body of the packing box as shown in  FIG. 5 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  in conjunction with  FIGS. 2 and 4  show the basic configuration of the packing box in accordance with the invention. First of all, there is a body  1  which has been produced from plastic material with a peripheral jacket  2 , which is preferably slightly conically shaped, and a carrier plate  5  which is provided with insertion openings  3  for the pipette tips  4  which are shown in  FIG. 2 .  FIGS. 1, 4  and  5 , in combination, also show a bottom  6  which is made of plastic material, while the figures all show a cover  7  which made of plastic material.  
      In the prior art which forms the starting point, the cover  7  is made as a separate plastic part which can be slipped on. In principle, this can also be the case for the packing box of the invention.  
      In this embodiment, the carrier plate  5  is produced in one piece with the jacket  2 , especially injection molded in one piece. In this way, as shown in  FIG. 1 , a body  1  with the shape of an inverted trough is formed which has high inherent stiffness from the start. This is not achieved via high wall thickness of the plastic material, but integrated via the geometrical structure of the body  1 , the jacket  2  and the carrier plate  5 .  
      Furthermore, in the embodiment which is shown in  FIG. 1 , and preferred in this respect, the bottom  6  is produced in one piece with the body  1  and is connected to the jacket  2  of the body  1  on a lengthwise edge  8  or a transverse edge  9  of the jacket  2  via a film hinge  10 . In this embodiment, the connection of the bottom  6  to the jacket  2  of the body  1  is on a lengthwise edge  8 .  
      The production cost of the packing box of the invention can be reduced even more in the above explained manner.  
      In the illustrated preferred embodiment, it furthermore applies that the film hinge  10  can be comprised of several, especially three, individual hinges  10   a, b, c  which are located distributed over the length of the lengthwise edge  8  of the jacket  2 .  
      The bottom  6  can be fixed in the jacket  2  simply by pressing in and clamping. However, it is even more feasible, as shown, that on the other lengthwise and transverse edges  8 ,  9 , roughly at the height of the film hinge  10 , catch recesses  11  are formed for catch projections  12  which are provided laterally on the bottom  6 . In this embodiment, especially in  FIG. 1 , on the transverse edges  9  and on the lengthwise edge  8  which is opposite the lengthwise edge  8  which is provided with the film hinge  10 , a respective catch recess  11  is provided for each of corresponding catch projections  12  on the bottom  6  the catch projections.  
      Therefore, the bottom  6  is folded in after the body  1  with the bottom  6  falls out of the injection tool and is then locked in place by means of catch projections  12  in the catch recesses  11 .  
      The preferred embodiment which is shown in the drawings, furthermore, is shown having a peripheral, preferably laterally projecting, base  13  made on the jacket  2  and which forms the lengthwise and transverse edges  8 ,  9 . The base  13  has an additional stiffening function and is also used as an edge for stably setting down the packing box.  
      In this embodiment, it is also provided that the lengthwise edge  8  of the jacket  2 , on which the film hinge  10  is formed, is shortened by a certain amount as compared to the other lengthwise and transverse edges  8 ,  9 . In this embodiment, this shortening is accomplished by the base  13  being shortened to this extent, or optionally also, its being completely absent. In this embodiment, the base  13  is reduced here to a narrow edge strip on which the individual hinges  10   a,    10   b,    10   c  of the film hinge  10  are made.  
      Basically, it would be possible to form the bottom  6  with an area that is equal with that bounded by the lengthwise and transverse edges  8 ,  9  of the jacket  2 . The illustrated embodiment described above is, however, more advantageous with the bottom  6  which is implemented there and which is countersunk in the jacket  2  because, in this way, there is an additional stiffening function for the body  1  by means of the bottom  6 . This has already been explained above.  
      The shortened lengthwise edge  8  and the base  13  offers the feasible possibility of arranging the bottom  6  countersunk in the remaining jacket  2  in the finished state of the packing box. This can be easily recognized, for example, from  FIG. 4  in the sectional representation shown there.  
      It was pointed out at the beginning of this description that it is of great interest to the teaching of this invention that material use be reduced as much as possible in the packing box of the invention in order to be able to use the packing box as a disposable box. The stiffness of the body  1  is of special importance in this respect. In the illustrated preferred embodiment, the stiffness is further increased in that the jacket  2  of the body  1  is provided with preferably corrugated ribs  14  which run from the carrier plate  5  to the edge  8 ,  9 .  FIG. 3  shows the corrugated shape of the ribs  14  which continue in the cover  7  as well. In this embodiment, it applies that the base  13  does not continue the ribs  14 , but is made and arranged to project on the edge side and to run smoothly around the periphery. This yields a smooth and straight termination on the lower edge  8 ,  9  of the jacket  2 .  
      The stiffening of the jacket  2  which is achieved by the ribs  14  increases its buckling resistance; this is especially important, for example, when the packing box is being used with the pipette tips  4  inserted by means of a multi-channel pipette, for example, an eight-channel pipette. The forces which occur in this case are rather considerable, but in spite of the low wall thickness of the jacket  2  they are easily accommodated by this jacket  2  due to the ribs  14  and the overall torsional stiffness of the arrangement. Wall thicknesses in the millimeter range, down to the lower boundary which is dictated by the filling behavior of the injection molding tool, can be accomplished, not only for the jacket  2 , but to the corresponding degree also for the carrier plate  5 .  
      It has been repeatedly pointed out above that the packing box for pipette tips which is addressed here is made of plastic material, especially is produced in an injection molding process. It has been shown that the use of polypropylene (PP) as the plastic material is especially economical and advantageous. This is associated with low production costs, the chemical resistance being broad. Polypropylene is chemically inert and can be effectively sterilized by irradiation with gamma rays.  
      With consideration of the flow behavior of the respective thermoplastic, wall thicknesses of roughly  1 . 0  mm can be achieved, optionally down to roughly 0.7 mm, which are on the order of the lower boundary which is dictated by flow technology.  
      For a long time, with respect to a packing box for pipette tips in accordance with the invention, essentially something has been done for a special configuration of the body  1  and the bottom  6 . The illustrated embodiment which is preferred in this respect however shows, furthermore, that here the cover  7  is not made as a separate component which can be slipped on, but a part of the hinge  17  for the cover  7  is molded to the carrier plate-side lengthwise edge  15  or transverse edge  16 , preferably on the lengthwise edge  15 , of the jacket  2 , and the cover  7  is pivotally coupled by means of the corresponding opposing part of the hinge  17 . Basically, the hinge  17 , which is three spaced hinges in this embodiment, can in fact be made in two parts. Then the cover  7  would be injected in a separate injection tool and subsequently combined with the body  1 .  
      The illustrated preferred embodiment, however, shows that the cover  7  is made in one piece with the body  1  from plastic material and that the hinge  17  is made in one piece as a film hinge. As already explained, here the hinge  17 , especially made as a film hinge, is comprised of several, especially three, individual hinges  17   a,    17   b,    17   c,  which are arranged distributed over the length of the upper lengthwise edge  15 .  
      The prior art extensively discloses hinge structures; see, for example, the published International Patent Application WO 00/29113 A1 mentioned in the Background portion. The corresponding hinge structures for a multipart packing box can also be taken therefrom.  
      The execution of the hinges of the type under discussion for plastic parts as film hinges follows, for example, from U.S. Pat. No. 5,145,646, the disclosure of which in this regard is hereby incorporated by reference. Here, there is a hinge  17  of plastic parts which is made as a film hinge and which in, an especially preferred manner, has a pivot limit, especially to an opening angle of roughly 1000, that is obtained via a special dual-leg construction.  
      Furthermore, in the teaching of this invention, it is also advantageous that the hinge  17 , especially the film hinge, of the cover  7  is made self-opening. (see, German Patent DE 196 45 892 C2). That is, as a result of the internal material forces, a film hinge of thermoplastic inherently has a restoration function which can lead to self-opening of the cover  7 . This is entirely independent of the pivot limit.  
      The above explained configuration of the hinge  17 , especially in its configuration as a film hinge with a one-piece execution of the cover  7  with the body  1 , results in that the edge of the cover  7  is pressed with one hand and then the cover snaps back independently, and is held in the desired open position by the restoration function of the hinge  17  which is made as a film hinge; the open position makes the pipette tips  4  in the carrier plate  5  easily accessible. The pivot limit which was addressed above obviates the necessity of a manipulation which requires two-hand operation when the cover  7  is closed again. The described angular position of the cover  7  also allows one hand operation here.  
      In the above explained construction, it is especially advantageous if there is a catch connection  18  between the cover  7  and the body  1  on the lengthwise edge  8  or on the transverse edge  9  which is opposite the hinge  17 .  
      It is advantageous for the catch connection  18  to be made as a lock and centering with the corresponding possibility of opening with one hand, as is disclosed, for example, in published International Patent Application WO 00/29113 A1 or as is known otherwise from practice. In the drawings,  FIG. 2  shows centering projections  18 ′ on the two transverse edges of the cover  7  which correspond to the centering openings  18 ″ on the transverse edges  16  of the body  1 . This construction leads to further optimization of the interaction of the cover  7  and the body  1  in the sense of optimum torsional stiffness of the overall arrangement.  
      Still further, the illustrated preferred embodiment shows, as is especially apparent in  FIGS. 2 and 4 , that the body  1  has a peripheral sealing step  19  for the edge of the cover  7  on the carrier plate-side lengthwise and transverse edges  15 ,  16 . Thus, an especially effective, tight closure results which again increases the torsional stiffness of the packing box overall with the cover  7  closed. The correspondingly configured catch connection  18  with the centering projections leads to the sealing step  19  of the edge of the cover  7  always being reached reliably and free from sticking.  
      Especially when the bottom  6  in the jacket  2  of the body  1 , as shown, is made countersunk and when the jacket  2  has sufficient conicity, the cover  7  in the edge-side dimensions is already, by itself, so much smaller that the packing box can be stacked on another packing box with the base  13  extending over the cover  7  on the edge side. In this way, lateral fixing of a packing box on another packing box is ensured. It is possible to stack several packing boxes on top of one another for storage and transport, and for example, to fix them with a vertically encompassing sleeve or a corresponding adhesive strip or tensioning belt.  
      The illustrated, preferred embodiment, in the above explained connection, shows another inherently interesting measure in that the bottom  6  and the cover  7  are provided with form-fitted structures  20  on their surface which are made and arranged corresponding to one another. These additional form-fitting structures  20 , in this embodiment, are made as beads which run crosswise, and yield additional fixing for purposes of the stacking capacity of the packing boxes.  
      Overall the proposed packing box, especially for pipette tips, as a disposable box, should more than compensate for the material use which is slightly higher than in re-usable boxes by savings in outfitting in the production process and in handling in the laboratory.