Abstract:
An infusion pump has a housing ( 10 ) accommodating a pump finger mechanism ( 12 ). The pump finger mechanism ( 12 ) acts on a pump hose ( 13 ) fastened at holders ( 16, 21 ) of the housing. The pump hose ( 13 ) is supported by a door ( 24 ). In order to facilitate proper and positionally correct placement of the pump hose, one of the holders ( 16 ) includes an oblique pin. The associated transition piece ( 15 ) of the pump hose ( 13 ) has a hole ( 18 ) with the same inclination angle as the oblique pin. The other transition piece ( 20 ) is of a different structure so that the transition pieces cannot be mixed up. A longitudinal color strip ( 29 ) on the pump hose is provided to visually indicate any twisting of the hose.

Description:
RELATED APPLICATIONS  
         [0001]    This application claims priority from German Patent Application No. 202 09 663.7, filed on Jun. 21, 2002, incorporated herein by reference for all legitimate purposes and relied upon for priority.  
         FIELD OF INVENTION  
         [0002]    The invention refers to an infusion pump comprising an pump hose with respective transition pieces at the opposite ends, a housing accommodating a pump finger mechanism and having two holders for attaching the two transition pieces, and a door provided at the housing which forms a counter bearing for supporting the pump hose.  
         DESCRIPTION OF RELATED ART  
         [0003]    From teachings in DE 8406203 U1, co-owned with the present application, an infusion pump is known comprising a housing for accommodating an exchangeable pump hose. A housing is provided with a pump finger mechanism continually squeezing the hose from top to bottom, thereby causing a volumetric conveying of the liquid contained in the pump hose. The pump hose is made of a relatively soft flexible material, especially silicone, its two ends being equipped with transition pieces to which a supply hose and a discharge hose of flexible plastics material respectively, are connected. The housing in provided with holders into which the transition pieces are hooked. In this manner, it is possible to attach the pump hose to the housing in a defined manner. Both holders and the associated transition pieces are designed such that the upper transition piece only fits into the upper holder and the lower transition piece only fits into the lower holder. However, the length of the pump hose allows a twisting of the pump hose, where, for example, the lower holder is twisted by  360 ° with respect to the upper holder. This bears the risk of a greater deviation from the set output volume or, in the worst case, a free flow. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0004]    In the figures:  
         [0005]    [0005]FIG. 1—is a perspective view of a part of the infusion pump with a housing and a pump hose exchangeably fastened thereto,  
         [0006]    [0006]FIG. 2—is a schematic vertical section through the upper holder and the transition piece fastened thereto,  
         [0007]    [0007]FIG. 3—is a front view of the pump hose fastened to the housing, and  
         [0008]    [0008]FIG. 4—is a perspective view of the upper transition piece prior to being fastened to the hose part of the pump hose. 
     
    
     DETAILED DESCRIPTION  
       [0009]    The following is a detailed description of an embodiment of the invention with reference to the drawings.  1000101  The infusion pump illustrated in FIG. 1 comprises a housing  10  generally designed similar to the housing of the infusion pump of DE 8406203 U1. In a front wall  11  of the housing  10 , an opening  11   a  is provided behind which a pump finger mechanism  12  of a finger pump (not illustrated) is arranged. The finger pump comprises numerous sequentially arranged fingers which are pressed one after the other from top to bottom against the pump hose and compress the same, so that the liquid contained therein is transported peristaltically from top to bottom. The pump finger mechanism  12  is covered by an elastic cover.  
         [0010]    A pump hose  13  is installed in front of the opening  11   a . The pump hose  13  comprises a length  14  of soft elastic hose, preferably made of silicone. For example, the length may be about 90 mm, the inner diameter 4 mm, and the outer diameter  6  mm. Fastened at the upper end of the length  14  of hose is an upper transition piece  15 . This transition piece  15  is hung into an upper holder  16  of the housing  10 . This holder  16  has two pins  17  arranged side by side and on the same level, projecting obliquely upward from the front wall  11  of the housing, as illustrated in FIG. 2. The transition piece  15  has two channel-shaped holes  18  extending obliquely upward, the axis thereof extending at the same angle as that of the pins  17 . The transition piece  15  is connected with a supply hose  19  of flexible plastic material.  
         [0011]    The transition piece has a front side  15   a  and a rear side  15   b . The rear side  15   b  faces the front wall  11  of the housing. If the transition piece were mounted such that its front side  15   a  faced the front wall  11  of the housing, the transition piece would not flatly abut on the front wall  11  of the housing, but would project obliquely therefrom.  
         [0012]    Accordingly, at least one of the holders cooperates with the associated transition piece by at least a combination of an oblique pin and an oblique hole to be slipped thereon, the pin and the hole being inclined the same with respect to the longitudinal axis of the installed pump hose.  
         [0013]    With the pump hose installed properly, the oblique pin fits into the hole that has the same inclination so that the transition piece flatly abuts on the housing. When the transition piece is improperly applied to the housing, the transition piece is orientated obliquely with respect to the housing so that a bulge is caused in the hose, thereby impeding or preventing the door from being closed. Thus, an orderly operation of the pump is made impossible when the hose is placed improperly (rear up front). A construction according to certain aspects of the invention, serves to reduce improper placement of the pump hose.  
         [0014]    In an exemplary embodiment, the at least one oblique pin is formed at the holder and the at least one oblique bole is formed in the transition piece. Further, in a preferred embodiment of the invention, two parallel pins are provided at the holder and two parallel holes are provided in the transition piece. Yet, it is also possible to provide the pin at the transition piece and the hole in the holder.  
         [0015]    The hole is not a mere opening in a flat plate, but a cylindrical channel extending obliquely to the central plane of the transition piece.  
         [0016]    The lower end of the pump hose  13  is equipped with a lower transition piece  20  hooked into a holder  21  of the housing. The transition piece  20  has two hook-shaped locking clamps  22  embracing the holder  21 . The holder  21  is a transverse bar formed to the front wall  11 . The bar has an opening for the passage of the discharge hose  23  connected to the transition piece  20 . The transition pieces  15 ,  20 , together with the length  14  of hose, form the pump hose  13 . Together with a supply hose  19  and a discharge hose  23 , the pump hose  13  forms a hose set which is a disposable article replaced after use.  
         [0017]    A door  24  is provided at the housing  10  as a counter-bearing for the pump hose  13 , the door being adapted to be swiveled about a vertical axis  25  and being locked at a closing member  26 . The door  24  is arranged opposite the pump finger mechanism  12  and has an abutment surface  27  where the length  14  of hose is compressed by the pump finger mechanism  12 . Above the abutment surface  27 , the door  24  has recesses  28  for receiving the ends of the pins  17  of the holder  16 .  
         [0018]    Thus, according to an exemplary embodiment of the invention, both holders are of different construction, each of the two transition pieces being adapted to the construction of the associated holder. In this manner, top and bottom of the pump hose cannot be interchanged, since the lower transition piece does not mate with the upper holder and the upper transition piece does not mate with the lower holder.  
         [0019]    [0019]FIG. 3 illustrates a front view of the properly installed pump hose  13 . At the front side of the length  14  of hose that is visible to the user when the door  24  is open, a longitudinal color strip  29  is provided. The color strip may consist of food colors applied as by rolling on to hose during extrusion prior to the hardening of the hose material. The color strip  29  would make visible a twisting of the lower transition piece  20  by 360° in the event that the length  14  of hose were helically twisted.  
         [0020]    In an exemplary embodiment, the pump hose is provided with a longitudinal color strip. In this manner, torsional twisting of the pump hose can easily be recognized visually.  
         [0021]    In FIG. 4, the transition piece  15  is illustrated in its open state prior to its being mounted to the length  14  of hose. The transition piece  15  has a tubular pin  30  onto which the length  14  of hose can be slipped. A transverse hinge portion  31  extends at an end of the tubular pin  30 , which projects towards opposite ends from the upper opening  32  of the tubular pin  30 . The supply hose  19  is inserted into the upper opening  32  and glued. The hinge portion  31  is bent in U-shape and flanges  33  and  34  project from its legs, respectively. The flanges  33 ,  34  each include a tunnel  35  and form two half shells  36 ,  37  whose flanges  33 ,  34  can be pressed against each other and whose tunnels  35  then combine to a cylindrical channel coaxially enclosing the tubular pin  30 . The tubular pin  30  forms an inner support for the end of the length  14  of hose clamped and fixed by the half shells  36 ,  37 .  
         [0022]    The invention addresses a problem of improving the attachment of transition pieces to a pump hose. Where the soft elastic pump hose, often made of silicone, cannot be glued or welded to other components, a mechanical connection between these parts has been found to be required. Presently, the end of the pump hose is slipped onto a tubular pin of the transition piece. Subsequently, a tensioning ring is placed around the slipped-on end of the pump hose to fix the same on the tubular pin in a sealing manner.  
         [0023]    The two transition pieces  15  and  20  consist of hard plastic material such as ABS. They are fixed in the final position by ultra sound or heating stamps wherein they press the length of hose onto the hard tubular pin. The entire transition piece  15  illustrated in FIG. 4 is an integral plastics part that may be produced as an injection molded part. The hinge portion  31  radially abuts the upper end of the tubular pin  30  from opposite sides and passes into the same.  
         [0024]    Thus, what has been disclosed in one embodiment is an infusion pump with a pump hose such that both in case of an axial twist of the transition pieces with respect to each other and in case of an erroneous placement of the pump element (rear up front), the error is immediately visible and an operation of the pump becomes impossible, respectively.  
         [0025]    In one embodiment of the invention, a pump hose is provided with transition pieces at both ends, which has a high tensile strength and a substantially improved compression strength and is simple to manufacture.  
       Variations And Equivalents  
       [0026]    Spatial references such as “bottom”, “top”, “front”, “back”, “lower”, “upper”, “under”, and “central” are for purposes of illustration only, relative to the figures shown and are not limited to the specific orientation of the structure or movement directions as described.  
         [0027]    Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many other modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.