Abstract:
The sheath ( 30 ) comprises a tube ( 31 ) and an end piece ( 32 ) that comprises a foot ( 33 ) introduced into an end portion of the tube ( 31 ), and a head ( 34 ) arranged in the extension of the tube ( 31 ). The foot ( 33 ) comprises, on the outer surface ( 40 ) thereof, a plurality of annular ribs ( 41 - 44 ) facing the inner surface ( 45 ) of the tube ( 31 ). The head ( 34 ) comprises a shoulder ( 38 ) facing the section ( 39 ) of the tube ( 31 ), projecting over the root of the foot ( 33 ). The end piece ( 32 ) and the tube ( 31 ) are attached to the periphery of at least one of said annular ribs exclusively by intrinsic welding. The method comprises the step of carrying out a peripheral tightening of the outer surface ( 37 ) of the tube on a level with the ribs ( 41  - 44 ), and the step of applying a sonotrode to the outer surface ( 35 - 36 ) of the head ( 34 ).

Description:
FIELD 
       [0001]    The invention concerns the artificial insemination of livestock with semen contained in a straw. 
       BACKGROUND 
       [0002]      FIG. 1  of the accompanying drawings is a diagrammatic view in longitudinal cross-section of a straw for the preservation of a predetermined dose of liquid-based substance, in particular pure or diluted animal semen. 
         [0003]    The straw  10  shown in  FIG. 1  comprises a tube  11  and a stopper  12 . 
         [0004]    The tube  11  is conventionally made from extruded plastic material, with an inside diameter for example of 1.6 or 2.5 mm and a length of the order of 133 mm 
         [0005]    The stopper  12  is usually of the three-part type originally described in French patent 995 878, corresponding to British patent 669 265, i.e. formed by two plugs  13  and  14  made from a fibrous substance enclosing a powder  15  which, on contact with a liquid, is capable of transforming into an impermeable paste or gel adhering to the wall of the tube so that the stopper is liquid-tight. 
         [0006]    In the initial state, shown in  FIG. 1 , the stopper  12  is arranged close to the end  16  of the tube  11  and it is provided that in the filled state, the dose of liquid substance which must be preserved in the straw  10  is placed between the stopper  12  and the end  17  of the tube  11  that is the furthest from the stopper  12 . 
         [0007]    In order to fill the straw  10 , the end  16  is placed in communication with a vacuum source while the end  17  is placed in communication with a vessel containing the substance to be introduced into the straw. 
         [0008]    The air initially contained between the stopper  12  and the end  17  is sucked through the stopper while the substance moves forward in the tube until it encounters the stopper  12 , by the end  18  thereof that is turned towards the end  17  of the tube  11 , that is to say the end of the stopper  12  that can be seen on the right in  FIG. 1 . 
         [0009]    If necessary, the straw is welded close to one or both of its two ends  16  or  17  and is placed in cold storage. 
         [0010]    In order to empty the straw  10 , if necessary after cutting the welded end portions and thawing, there is inserted into the tube  11  a rod which comes to bear on the end  19  of the stopper  12  (which end is situated on the opposite side to the end  18 ). Using this rod, the stopper  12  is made to slide in the manner of a piston towards the end  17  or the end which corresponds after cutting the welded portion, which causes the expulsion of the dose of substance which had been introduced into the straw. 
         [0011]    When the straw such as  10  is used for the artificial insemination of livestock, in particular bovine, ovine or caprine livestock, or rabbits, a reusable insemination syringe and a single-use sanitary sheath are used. 
         [0012]    The insemination syringe comprises a rigid tubular body, for receiving the straw filled with semen, and comprises the rod for driving the stopper, slidingly mounted in the rigid tubular body. 
         [0013]    Prior to insertion of the straw into the rigid tubular body, the rod is taken out or withdrawn as far as possible from the body at the proximal end, that is to say at the end which is manipulated by the inseminator during the operation, then the straw is inserted into the rigid tubular body at its distal end (the far end from the proximal end), the straw  10  being inserted with the end  16  of the tube  11  (the end closest to the stopper  12 ), first. The straw  10  is pushed into the rigid tubular body of the syringe until the end  16  of the tube  11  encounters a shoulder forming a pushing-in stop. 
         [0014]    The straw  10  is then in place in the rigid tubular body of the syringe. The end  17  of the tube  11  as well as a certain length of the tube  11  starting from that end remain outside the rigid tubular body, that is to say that a certain part of the straw  10  projects beyond the distal end of the rigid tubular body of the syringe. 
         [0015]    The sanitary sheath comprises a tube of which the inside diameter is such that the rigid tubular body of the syringe may be inserted therein. At one end (the proximal end) the tube of the sanitary sheath is open and at the other end (distal end) the sanitary sheath conventionally comprises a turned back edge forming a hem on the inside. Inside the sheath  3  a sliding sleeve member is disposed. 
         [0016]    The rigid tubular body of the syringe, in which the straw was placed in advance, is inserted into the sheath by its open end with the straw first, the straw inserts into the sliding sleeve member and drives it. The insertion into the sheath ends when the sliding sleeve member and the straw come to bear against the hem-forming turned back edge situated at the distal end of the sheath (which is the far end to the open end of the sheath tube). 
         [0017]    The sheath is then fastened to the rigid tubular body of the syringe, in general in the neighborhood of the proximal end of the sheath (open end of the tube) for example with a suitable ring. 
         [0018]    The tube  11  of the straw  10  is thus immobilized relative to the assembly formed by the tubular body of the syringe and by the sanitary sheath fastened to that body, since the end  16  of the tube  11  bears against the shoulder of the tubular body of the syringe and the end  17  bears against the hem-forming edge of the sanitary sheath. 
         [0019]    The assembly formed by the sanitary sheath and the syringe is then inserted into the animal and when that assembly is in place, the rod is used to make the stopper  12  of the straw  10  slide in order to eject the semen out from the tube  11  and out from the sheath tube by the aperture surrounded by the hem-forming edge. 
         [0020]    The role of the sliding sleeve member is to provide liquid-tightness for the liquids between the straw tube and the sheath tube in order for the semen to be properly ejected out from the sheath (and not lost between the straw tube and the sheath tube). 
         [0021]    French patent application 2 832 919, to which corresponds the United States patent US 2005/0107659 describes such a syringe and such a straw. 
         [0022]    Sanitary sheaths are also known in which the sliding sleeve member and the hem-forming turned back edge are replaced by a tip attached to the tube by an insertion fit or by bonding 
         [0023]    This tip comprises a tail inserted into an end portion of the tube and a head disposed in line with the tube. 
         [0024]    For the insertion fit between the tail and the end portion of the tube, the tail comprises annular ribs on its outside surface, facing the inside surface of the tube; the head comprising a shoulder facing the rim of the tube and jutting relative to the base of the tail. 
         [0025]    The tip comprises a duct opening into the tube at the proximal end of the tail (the far end of the tail from the head) and out of the sheath at the outside surface of the head. 
         [0026]    This internal duct of the tip comprises a portion oriented in the axial direction, narrowing from the proximal end of the tail, configured in order for the portion of the tube  11  of the straw  10  situated in the neighborhood of the end  17  (furthest end from the stopper  12 ) can enter the narrowing portion of the duct and advance to a stop position in which the portion of the tube  11  situated in the neighborhood of the end  17  is clamped around by the wall of that portion of the duct. 
         [0027]    This clamping round provides at the same time the stop for the pushing-in of the straw into the sheath and the liquid-tightness between the straw and the sheath. 
       SUMMARY 
       [0028]    The invention aims to provide a sanitary sheath of this type which is particularly reliable to use while being simple, convenient and economical to produce. 
         [0029]    To that end the invention provides a sanitary sheath for a syringe for insemination by straw, comprising a tube and a tip attached to the tube, which tip comprises a tail inserted into an end portion of the tube and a head disposed in line with the tube, said tip comprising a duct opening into the tube at the proximal end of the tail and out from the sheath at the outside surface of the head, which duct comprises an axially oriented portion narrowing from the proximal end of the tail, said tail comprising on its outside surface a plurality of annular ribs facing the inside surface of the tube, said head comprising a shoulder facing the rim of the tube and jutting relative to the base of the tail; characterized in that the tip and the tube are exclusively fastened by intrinsic welding at the periphery of one or more said annular ribs. 
         [0030]    Whereas in the sanitary sheaths already known the attachment between the tube and the tip is made by mere insertion fitting of the tip or else by bonding, in the sanitary sheath according to the invention, the tip and the tube are attached by intrinsic welding, that is to say with the material of the tube and the material of the tip, without addition of external material. 
         [0031]    This is particularly secure, since the sheath according to the invention avoids the chemical hazards liable to be caused by adhesives, and in particular by the solvents which they contain, and also the hazards liable to occur of pulling off of the tip, in particular inside the animal during the insemination, with the sheaths of which the tip is merely fitted by insertion in the tube. 
         [0032]    In addition, on account of the fact that the tip is welded to the tube exclusively by one or more of the annular ribs of the tail, that is to say that the welds are made exclusively inside the tube, none of these welds can create an edge liable to injure the animal. 
         [0033]    It is to be noted in particular that in the sheath according to the invention, the rim of the tube and the shoulder of the head, which face each other, are not welded. 
         [0034]    Were a weld to be present in that zone, there would be the risk of having flash outside the tube. 
         [0035]    It is furthermore to be noted that the sanitary sheath according to the invention is capable of being produced simply, conveniently and economically. 
         [0036]    According to preferred features: 
         [0037]    the tip and the tube are welded at the location of several said annular ribs, with a different depth of weld for at least two said annular ribs; 
         [0038]    the depth of weld is greater the further the annular rib is from the proximal end of the tail of the tip; and/or 
         [0039]    each said annular rib comprises, on the side turned towards the distal end, a straight surface which projects from a trough surface; and from the side turned towards the proximal end, a surface inclined inwardly and towards the proximal end. 
         [0040]    According to a second aspect, the invention is also directed to a method for manufacturing a sanitary sheath as set out above, comprising: 
         [0041]    the step of providing a tube and a tip comprising a tail and a head, said tip comprising a duct opening at the proximal end of the tail and at the outside surface of the head, which duct comprises an axially oriented portion narrowing from the proximal end of the tail, said tail comprising on its outside surface a plurality of annular ribs, said head comprising a shoulder jutting relative to the base of the tail. 
         [0042]    the step of inserting the tail into an end portion of the tube until the head is disposed in line with the tube, the annular ribs then facing the inside surface of the tube, the rim of the tube facing said shoulder; 
         [0043]    the step of performing peripheral clamping on the outside surface of the tube opposite said ribs; and 
         [0044]    the step of applying a sonotrode for ultrasonic welding to the outside surface of the head. 
         [0045]    According to preferred features, the outside diameter of said annular ribs varies from one rib to the other, increasing from the proximal end of the tail. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0046]    The disclosure of the invention will now be continued by the description of an embodiment, given below by way of illustrative and non-limiting example, with reference to the accompanying drawings, in which: 
           [0047]      FIG. 1  is a diagrammatic view in longitudinal cross-section of a straw according to the prior art; 
           [0048]      FIG. 2  is a cross-section view of the distal end of a sheath according to the invention; and 
           [0049]      FIGS. 3 and 4  are side views of the head of that sheath, taken respectively from the top and from the front of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0050]    The sanitary sheath  30  illustrated in  FIG. 2  is provided to cooperate as explained above with an artificial insemination syringe in which is disposed a straw such as the straw  10  illustrated in  FIG. 1 . 
         [0051]    The sanitary sheath  30  comprises a tube  31  and a tip  32 . 
         [0052]    The tip  32  comprises a tail  33  inserted into an end portion of the tube  31  and a head  34  disposed in line with the tube  31 . 
         [0053]    Remote from the tail  33 , the head  34  has a rounded convex end surface  35  forming the distal end surface of the sanitary sheath  30 . 
         [0054]    The part  36  of the outside surface of the head  34  situated between the surface  35  and the tube  31  is here of circular section, of the same diameter as the outside surface  37  of the tube  31 . Thus, the surfaces  36  and  37  are flush with each other. 
         [0055]    The head  34  has a shoulder  38  facing the rim  39  of the tube  31  and jutting relative to the base of the tail  33 . 
         [0056]    The tail  33  comprises on its outside surface  40  annular ribs of which there are four here, referenced  41  to  44  in the order of proximity to the head  34 , with the rib  41  the closest to the head  34  and the rib  44  the furthest away. 
         [0057]    The attachment between the tube  31  and the tip  32  is achieved exclusively by intrinsic welding between the periphery of each of the ribs  41  to  44  and the inside surface  45  of the tube  31 . 
         [0058]    As explained below, these welds are made by ultrasound. 
         [0059]    In the tip  32  there is formed a duct opening into the tube  31  at the proximal end of the tail  33  (the far end from the head  34 ) and outside the sheath at the outside surface of the head  34 , here by two apertures  51  ( FIGS. 3 and 4 ) situated at the junction between the portions  35  and  36  of the outside surface of the head  34 . 
         [0060]    The duct comprises a transversely oriented portion  52  going from one to the other of the apertures  51  and an axially oriented portion  53 , disposed between the proximal end of the tail  33  and the portion  52 . 
         [0061]    The portion  53  of the duct narrows from the proximal end of the tail  33 . 
         [0062]    The portion  53  is configured such that the portion of the tube  11  of the straw  10  situated in the neighborhood of the end  17  (furthest end from the stopper  12 ) can be inserted into the portion  53  and advance to a stop position in which the portion of the tube  11  situated in the neighborhood of the end  17  is clamped around by the wall which delimits the portion  53 . 
         [0063]    This clamping round provides at the same time the stop for the pushing-in of the straw into the sheath and the liquid-tightness between the straw and the sheath. 
         [0064]    The outside surface  40  of the tail  33  will now be described in more detail with the aid of  FIGS. 3 and 4 . 
         [0065]    Each of the ribs  41  to  44  comprises: 
         [0066]    on the side turned towards the distal end (which side can be seen to the right in  FIGS. 2 to 4 ) a straight surface  60 , that is to say a surface oriented according a transverse plane, which projects from a trough surface  61 ; and 
         [0067]    on the side turned towards the proximal end (which side can be seen to the left in  FIGS. 2 to 4 ), a surface  62  inclined inwardly and towards the proximal end. 
         [0068]    Here, the trough surfaces  61  have the same diameter and the inclined surfaces  62  have the same inclination. 
         [0069]    The inclined surface  62  of the ribs  41 ,  42  and  43  is joined to its base (the part of smallest diameter situated on the opposite side to the straight surface  60 ) at the trough surface  61  from which projects the straight surface  60  of the next rib. 
         [0070]    The inclined surface  62  of the rib  44  joins to its base at a guide surface  63  of which the diameter is slightly greater than the diameter of the trough surfaces  61 . 
         [0071]    The base surface of the shoulder  38  of the head  34  joins to a wedging surface  64  of which the diameter is slightly greater than the diameter of the guide surface  63 . 
         [0072]    Between the wedging surface  64  and the nearest trough surface  61 , is located a transition surface  65  which is inclined inwardly and towards the distal end. 
         [0073]    The outside diameter of the ribs  41  to  44 , which here corresponds to the greatest diameter of the straight surfaces  60  and of the inclined surfaces  62 , varies from one rib to the other, increasing from the proximal end of the tail  33 . 
         [0074]    Thus, the outside diameter of the annular rib  44 , which is the closest to the proximal end, is smaller than the outside diameter of the rib  43 , which is itself smaller than the outside diameter of the rib  42 , which is itself smaller than the outside diameter of the rib  41 . 
         [0075]    The straight surface  60  and the inclined surface  62  of the rib  41  meet. 
         [0076]    For each of the ribs  42 ,  43  and  44 , there is, between the straight surface  60  and the inclined surface  62 , a cylindrical surface  66  having the outside diameter of the corresponding rib. 
         [0077]    A description will now be given of how the tube  31  and the tip  32  are attached to each other. 
         [0078]    First the tail  33  of the tip  32  is fitted by insertion in an end portion of the tube  31  until the rim  39  comes opposite the shoulder  38 . 
         [0079]    The diameter of the inside surface  45  of the tube  31  is capable of varying to a relatively great extent, for example by 0.1 mm, due to its manufacture by extrusion. 
         [0080]    The ribs  41  and  44  have been configured accordingly: 
         [0081]    when the diameter of the inside surface  45  is at the maximum of the range of variation, the inside surface  45  comes at least into contact with the rib  41 ; and 
         [0082]    when the diameter of the inside surface  45  is at the minimum of the range of variation, the inside surface  45  comes into contact with each of the ribs  41  to  44 . 
         [0083]    The fact that the outside diameter of the ribs  41  to  44  increases from the proximal end facilitates the insertion of the tail  33  into the tube  31 . 
         [0084]    The surface  63  gives first guidance along the inside surface  45  before the latter encounters the rib  44 . 
         [0085]    When the tip  32  is inserted into the terminal portion of the tube  31 , the surface  64  stabilizes the inside surface  45  in the neighborhood of the shoulder  38 . 
         [0086]    Once the tail  33  of the tip  32  has been inserted into the terminal portion of the tube  31 , peripheral clamping on the outside surface  37  of the tube  31  is carried out opposite the ribs  41  to  44  and a sonotrode for ultrasonic welding is applied to the outside surface of the head  34 . 
         [0087]    Because the only location at which there is clamping between the surface of the tip  32  and the surface of the tube  31  is opposite the ribs  41  to  44 , and because of the fact that those ribs form an edge, it is at the zone of contact between the ribs  41  to  44  (periphery of those ribs) and the tube  31  that their materials will heat up, soften and mix, which, after cooling, will form an intrinsic weld, that is to say involving only the material of the tube  31  and the material of the tip  32 . 
         [0088]    Of course, the material of the tube  31  and the material of the tip  32  are selected so they can be welded ultrasonically and more generally intrinsically, that is to say that those materials are mixable when they are have been softened. 
         [0089]    Here, the material of the tube  31  and the material of the tip are transparent. They are respectively PVC (poly vinyl chloride) and PMMA (poly methyl methacrylate). 
         [0090]    In principle, the ribs  41  to  44  are configured such that each of them is welded to the tube  31 . 
         [0091]    Given the difference in diameters of the ribs  41  to  44 , the depth of weld increases from the proximal end, that is to say that the depth of weld between the rib  44  and the tube  31  is smaller than the depth of weld between the rib  43  and the tube  31  which is itself smaller than the depth of weld between the rib  42  and the tube  31  which is itself smaller than the depth of weld between the rib  41  and the tube  31 , as can be seen in  FIG. 2 . 
         [0092]    When the diameter of the inside surface  45  is very great, the weld will be made at least with the rib of greatest diameter, that is to say the rib  41 . 
         [0093]    It should be noted that the welds between the tip  32  and the tube  31  are made exclusively at the location of the ribs  41  to  44 . 
         [0094]    In particular, there is no weld between the shoulder  38  of the tip  32  and the rim  39  of the tube  31 . 
         [0095]    This makes it possible to avoid weld flash projecting from the outside surface of the tube  31  or from the head  34 ; and the risks of injuries to the animal, which could be caused by such a weld flash, are thus avoided. 
         [0096]    On the contrary, in a general manner, as the welds are exclusively internal to the sheath  30  those risks are eliminated. 
         [0097]    In a variant not illustrated, the number of annular ribs of the outside surface of the tail and the tip is different from four, for example two or five. 
         [0098]    In another variant not illustrated, the duct internal to the tip such as  32  is differently conformed, for example being oriented uniquely in the axial direction, while opening by the center of the surface such as  35 . 
         [0099]    Numerous other variants are possible according to circumstances, and in this connection it is to be noted that the invention is not limited to the examples described and shown.