Abstract:
A dispensing pump for a fluid product, including a pump body ( 10 ) in which at least one piston ( 20, 30 ) slides, wherein a pump chamber ( 40 ) is defined between an input valve ( 50 ) and an output valve ( 60 ), and said pump body ( 10 ) extends towards the inside of a tank ( 2 ) through a plunger tube ( 70 ) said input valve ( 50 ) being sealably connected to said plunger tube ( 70 ), the pump comprising a return spring ( 5 ) which brings said pump back towards its rest position, characterized in that said spring is positioned out of any contact with the fluid product.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of pending U.S. provisional patent application Serial No. 60/291,027, filed May 16, 2001, and priority under 35 U.S.C. §119(a)-(d) of French patent application No. FR-01.04594, filed Apr. 4, 2001. 
     
    
     
       TECHNICAL FIELD  
         [0002]    The present invention relates to a dispensing pump for a fluid product and to a dispensing device for a fluid product incorporating such a pump.  
         BACKGROUND OF THE INVENTION  
         [0003]    As is known, a pump generally includes a pump body which defines a pump chamber usually positioned between an input valve and an output valve. In order to dispense the product contained in the pump chamber, the user actuates an actuating rod connected to a piston which slides in the pump body which generally causes the displacement of a second piston, called the low piston and which slides in a portion of the pump body with a reduced diameter until the output valve opens which causes the product contained in the pump chamber to be expelled under pressure. When the user lets go and the actuating rod moves back up to its rest position, under the action of a return spring, some product is sucked into the inside of the pump chamber through said input valve.  
           [0004]    The object of the present invention is to overcome certain drawbacks which arise with the type of pump.  
           [0005]    Thus, a drawback arises due to the relatively large dead space which exists upstream from the input valve of the pump chamber, in the flow direction of the product. Indeed, the plunger tube generally opens into the bottom of the pump body, so that this entire portion of the pump body which is located below the low piston and the input valve, is filled with product. This has the effect of inducing a non-negligible back pressure which makes the complete emptying of the tank difficult.  
           [0006]    One of the objects of the present invention is to reduce the dead spaces and the back pressure of the pump.  
           [0007]    The object of the present invention is also to improve priming of this type of pump, the latter generally requiring three or four actuation jolts of the pump before obtaining a completely filled pump chamber.  
           [0008]    The object of the present invention is also to reduce the number of priming jolts required for priming the pump.  
           [0009]    On the other hand, the return spring of the pump is generally mounted between the bottom of the pump bottom and the seat of the input valve which is floatably mounted inside said pump body. The spring is therefore in contact with the product, this may cause a certain number of problems when said spring is metal, as is often the case. The documents U.S. Pat. No. 4,511,069, FR-1 486 392 and DE-28 38 613 disclose such devices.  
           [0010]    Another object of the present invention is to suppress any contact between the return spring of the pump and the product to be dispensed.  
         BRIEF SUMMARY OF THE INVENTION  
         [0011]    Accordingly, the object of the present invention is a A dispensing pump for a fluid product, including a pump body in which at least one piston slides, wherein a pump chamber is defined between an input valve and an output valve, and said pump body extends towards the inside of a tank through a plunger tube said input valve being sealably connected to said plunger tube ( 70 ), the pump comprising a return spring which brings said pump back towards its rest position, characterized in that said spring is positioned out of any contact with the fluid product.  
           [0012]    Advantageously, the pump body includes an upper aperture in which an actuating rod is assembled, and a lower aperture in which the plunger tube is assembled, wherein said pump body or said plunger tube includes, at said lower aperture of the pump body, a tubular portion axially extending towards the inside of the pump body, wherein said input valve is sealably connected to said tubular portion.  
           [0013]    Advantageously, the input valve includes an input valve seat movable within said pump body and an input valve component, such as a ball, which selectively seals and opens said input valve, wherein said input valve seat includes, upstream from said input valve component in the flow direction of the product, an axial tube, one end of which sealably cooperates with said tubular portion of the pump body or plunger tube.  
           [0014]    Advantageously, the return spring of the pump is positioned in the pump body between the seat of the input valve and the pump body or a component securely fixed to the pump body, such as a portion of the plunger tube.  
           [0015]    Advantageously, said axial tube of the input valve seat sealably slides inside or outside of said tubular portion.  
           [0016]    Advantageously, the input valve seat includes, upstream from the valve component, a radial through-hole for allowing the air contained in the pump chamber to be discharged towards the tank before the first actuation of the pump.  
           [0017]    Advantageously, the output valve includes an output valve seat and an output valve component, wherein said output valve component includes an expended head cooperating with said output valve seat, wherein said output valve component is attracted to its closed position through the pressure of the product contained in the pump chamber, and is mechanically moved towards its open position at the end of the actuation stroke of the actuating rod.  
           [0018]    The object of the present invention is also a dispensing device for a fluid product including a tank for the fluid product and a pump made as described above. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    Other features and advantages of the present invention will appear more clearly in the following detailed description of a particular embodiment of the latter, which will be made with reference to the appended drawings, given as non-limiting examples, and wherein:  
         [0020]    [0020]FIG. 1 is a schematic transverse sectional view of an advantageous embodiment of the present invention, in the rest position, before the first actuation of the pump;  
         [0021]    [0021]FIG. 2 is a similar view to that of FIG. 1, during the priming of said pump; and  
         [0022]    [0022]FIG. 3 is a similar view to that of FIGS. 1 and 2, in the actuating position of said pump. 
     
    
     DETAILED DESCRIPTION  
       [0023]    Generally speaking, the present invention relates to a pump including a pump body  10  in which at least one piston  20 ,  30  slides, and in which a pump chamber  40  is defined between an input valve  50  and an output valve  60 . An object of the invention is to directly and sealably connect said input valve  50  to the plunger tube  70  which is the extension of the pump body  10  inside a tank  2  (which is illustrated only very schematically in dotted-lines in FIG. 3). This sealed connection between the input valve  50  and the plunger tube limits the dead space of the product contained upstream from said input valve  50 , which has the result of limiting back pressure, of facilitating priming of the pump, and of allowing the return spring  5  of the pump to be positioned away from any contact with the product to be dispensed.  
         [0024]    The invention will now be more specifically described with reference to the particular embodiment illustrated in the drawings.  
         [0025]    According to this advantageous embodiment, the pump includes a pump body  10  including an upper portion of a larger diameter  11  and a lower portion of a smaller diameter  12 . The upper portion  11  includes an upper aperture in which an actuating rod  1  is assembled, connected to a first piston  20 , called the high piston, which slides in said portion with a larger diameter  11  of the pump body. The lower portion  12  of the pump body includes a lower aperture in which a plunger tube  70  is assembled, and in which a second piston  30 , called the low piston equally slides. A pump chamber  40  is defined between an input valve  50  and an output valve  60 . The output valve  60  is formed at the level of the actuating rod  1 , which defines the seat of the output valve  61 , with which cooperates an output valve component  69 . Advantageously, this valve component  69  is made as a rod provided with a radially expanded head  68 , so that said output valve component  69  is pressed against the valve seat through the pressure of the product contained in the pump chamber  40  until said output valve component  69  is mechanically displaced away from said valve seat  61 , at the end of the actuation stroke of the actuating rod  1 . For this purpose, the valve component  69  includes a shoulder  67 , which at the moment of the expulsion, cooperates with a part of the pump suitable for moving the latter with respect to its valve seat  61 .  
         [0026]    In the present patent application, the general operation of this pump will not be described in more detail, as this has already been done within the framework of a French patent application filed on Oct. 23, 2000 by the same applicant (file number 00 13569).  
         [0027]    The input valve is formed by a valve seat  51  and an input valve component  59 , generally embodied as a ball. This ball may advantageously be made in glass or in plastic. The valve seat is floatably mounted inside the pump body and it cooperates with the low piston  30  so that it moves together with the latter when the pump is actuated. The valve seat  51  is stressed by the return spring of pump  5  which accordingly rests on said valve seat  51  on the one hand and on the other hand on the bottom of the pump body  10  or on a component  70  securely fixed to said bottom of the pump body.  
         [0028]    According to one aspect of the invention, said input valve seat  51  is directly and sealably connected to the plunger tube  70 . In the example illustrated in the figures, said input valve seat  51  includes, upstream from the input valve component  59  in the flow direction of the product, an axial tube  55  of a reduced size which extends towards the bottom of the pump body  10 . Correspondingly, the pump body  10 , or as illustrated in the figures, a component  70  fixed in the bottom of said pump body  10 , includes a tubular portion axially extending towards the inside of the pump body. The lower end  56  of the axial tube  55  of the input valve seat  51  sealably cooperates with said tubular portion  80 . In the examples illustrated in the figures, this tubular portion  80  is part of the plunger tube  70 , but forming this tubular projection  80  directly in the bottom of the pump body  10  may perfectly be contemplated. Also, the lower end  56  of tube  55  sealably slides inside the tubular portion  80 , but having this lower end of the tube  55  slide on the external wall of said tubular portion  80  may be contemplated.  
         [0029]    The fact that tube  55  connected to the input valve  50  sealably cooperates with the plunger tube  70 , results in that the return spring  5  may be positioned away from any contact with the product. This may notably be the case, if the tubular portion  80  is sealably assembled in the lower aperture of the pump body  10 . This promotes the stability of the product when the spring is made in metal and, generally prevents all the problems encountered with metal springs. Thus, with a glass or plastic ball  59 , the fluid product to be dispensed is no longer in contact with any metal component.  
         [0030]    On the other hand, the internal dimensions of tube  55  and of the tubular portion  80  are significantly less than those for the pump body  10 , the dead space of the pump is highly limited, as well as its back pressure. Actuation of the pump is therefore more reliable and the complete emptying of the tank is facilitated.  
         [0031]    Because of the cooperative seal between the axial tube  55  of the input valve seat  51  and the tubular portion  80  of the plunger tube  70 , a radial through-hole  53  is preferably provided upstream from the ball  59  of the input valve  50 . Indeed, when the pump is primed, as illustrated in FIG. 2, air is compressed and does not escape through the output valve  60  of the pump which remains closed, but escapes towards the lower portion  12  of the pump body  10  by passing inside the low piston  30 . As the input valve seat  51  sealably cooperates with the plunger tube  70  and said plunger tube  70  may be sealably mounted in the bottom of the pump body  10 , provision of this radial air hole  53  is advantageous for allowing the air to escape through said plunger tube  70  towards the inside of the tank, during the priming of the pump. The priming is facilitated because of the smaller dead spaces formed by this direct connection between the plunger tube  70  and the input valve  50 , so that the pump may operate after only one or two actuations of the latter.  
         [0032]    The present invention was described with reference to a particular embodiment of the latter, but it is understood that various modifications may be made by one skilled in the art, without departing from the scope of the present invention as defined in the appended claims.