Abstract:
A description is given of a sprayer of liquids ( 10 ) with trigger-operated pump comprising a body ( 11 ) which can be attached to the mouth of a container and a nozzle ( 16 ) of delivery of the liquid, in the body ( 11 ) being formed a pumping chamber ( 22 ) in communication with the interior of the container and with the delivery nozzle ( 16 ), via a one-way valve of suction and of delivery ( 30 ), in the outlet duct ( 29 ) for the liquid a system of precompression being placed comprising a piston ( 41 ) pushed with constant force by a spring ( 42 ) in occlusion of said outlet duct ( 29 ) such as to increase the pressure of the liquid in said outlet duct ( 29 ) during the pumping, and therefore the speed or the acceleration of the liquid in output from the nozzle ( 16 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The object of the present invention is a sprayer for liquids, in particular a pump sprayer actuated manually by means of a trigger lever, provided with a system of precompression suitable for expelling the liquid with a greater speed or acceleration. 
         [0002]    A sprayer generally comprises a main body provided with a base with a threaded ring nut or with bayonet coupling to be attached to the mouth of a container of liquid, a delivery nozzle wherefrom the liquid is sprayed, a trigger lever which can be actuated by hand by the user and a pump which can be actuated by the trigger lever to aspirate the liquid from the container by means of a dipper tube and spray it via the delivery nozzle. 
         [0003]    The pump provides a piston acting in a chamber formed in the body of the sprayer. The body of the sprayer comprises moreover an inlet duct which places in communication the interior of the container of the fluid with the chamber of the pump and an outlet duct which places in communication the chamber of the pump with the nozzle of the sprayer. A valve for fluid suction and delivery is provided inside or immediately upstream of the chamber of the pump, suitable for allowing in a selective and one-way manner the suction of the fluid from the container to the chamber of the pump and the delivery of fluid from the chamber of the pump towards the delivery nozzle. 
         [0004]    In order to accelerate the exiting of the liquid from the sprayer, or to guarantee a regular jet of the liquid, normally nebulised, aside from the speed of actuation of the trigger lever, systems of precompression have been proposed, which co-operate with the piston actuated by the lever in order to increase the pressure of delivery of the liquid. 
         [0005]    These known systems of precompression normally require numerous additional components in order to obtain the desired effect, with consequent increase in the cost of production. They are also somewhat complex and not easy to produce. 
         [0006]    One example is represented by the lever sprayer device described in WO 96/18572 which, when the pump is actuated, releases the air from a chamber of the sprayer inside a container whereto the sprayer is connected. This device comprises a piston assembly defined by a pump-piston sliding inside a pump-chamber and by a release piston integrated in the pump-piston and slidingly positioned inside a release chamber, a pressure regulator sliding inside a channel and suitable for allowing the passage under pressure of the liquid directed towards the sprayer nozzle, with said pressure regulator comprising a valve sliding on a pin provided with peripheral grooves and formed in said channel for the passage of the liquid and a contrast spring positioned around said pin. 
         [0007]    When the pump-piston is actuated manually by acting on the manual lever, it takes the liquid to be sprayed from the receptacle and pushes it against the valve thus causing a force of pressure on the same which slides in relation to the pin and, overcoming the action of contrast of the spring, allows the passage of the fluid via the grooves of the pin in the direction of the spray nozzle. The liquid impacts against the side wall of the valve and causes the raising thereof, acting against a membrane projecting perimetrically from the same. 
         [0008]    This known solution, however, has some important disadvantages linked to the fact that it is presented as a complex and costly device as regards manufacture and, moreover, requires the prior evacuation of the air contained in the pumping chamber not sufficient for allowing the raising of the valve and, only when said chamber is filled with the liquid aspirated from the container, the raising of the valve takes place and therefore the system of precompression starts to function. 
         [0009]    The object of the invention is that of providing a sprayer for liquids with system of precompression which is simple and economical to manufacture and highly reliable. 
         [0010]    Another object of the invention is that of providing such a system of precompression which can easily be adapted, with few actions, to existing sprayers. 
         [0011]    In particular the system of precompression that forms the object of the invention constitutes an improvement of the sprayer for liquids that is the object of the European patent EP 1585602, which is incorporated herein by reference in its entirety. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The sprayer for liquids with system of precompression which is the object of the invention has the features of the independent claims. 
         [0013]    Advantageous embodiments of the invention are further recited in the dependent claims. 
         [0014]    Substantially, in the outlet duct of the chamber of the pump, a second piston is provided, normally held in occlusion of this duct by a precompression spring, the elastic force whereof is overcome by the pressure of the fluid following actuation of the pump, with consequent displacement of the second piston and exiting of the fluid. 
         [0015]    In this phase the precompression spring acting on the second piston exerts an additional pressure on the fluid, which is delivered at a greater speed. 
         [0016]    Advantageously the aforesaid second piston and the precompression spring are placed in a widening of a vertical section of said duct of outlet from the chamber of the pump, which then continues with a horizontal section as far as the nozzle. 
         [0017]    The second piston blocks, in non-operational condition, the passage of the fluid from said vertical section to said horizontal section of the outlet duct. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Further features of the invention will be made clearer by the following detailed description, referred to one of its embodiments purely by way of a non-limiting example illustrated in the accompanying drawings, in which: 
           [0019]      FIG. 1  is a median sectioned view of a sprayer with system of precompression according to the invention; 
           [0020]      FIGS. 2 and 3  are similar views to that of  FIG. 1 , with the sprayer respectively in phase of suction and of delivery of the liquid; 
           [0021]      FIGS. 4 and 5  are views like those of  FIG. 2  of two alternative embodiments; and 
           [0022]      FIG. 6  shows an enlarged detail of the precompression spring mounted according to the embodiment as per  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    In the accompanying drawings a structure of sprayer is shown as described in the aforementioned European patent EP 1585602, whereto reference can be made for further details on the functioning of the sprayer, which will only be described in brief here. 
         [0024]    The sprayer according to the invention, denoted as a whole by reference numeral  10 , comprises a body  11  closed by a closure cap  12 . 
         [0025]    At the base of the body  11  of the sprayer an attachment ring nut  15  is rotatably mounted which has internal threading suitable for engaging with the external threading of the mouth of a container (not shown), suitable for containing a liquid, such as for example liquids for cleaning the home. Naturally the attachment of the sprayer on the container may also take place in a different way, for example by means of a bayonet coupling. 
         [0026]    The body  11  of the sprayer has a substantially L shape and ends in a delivery nozzle  16  with an opening from which the liquid is delivered. 
         [0027]    The delivery nozzle  16  is made up of a hole formed in a spray ring nut  16 ′ which can be rotated in a manner in itself known between a position of blocking and a position of activation of the spraying. 
         [0028]    For the actuation of the sprayer a trigger lever  17  is provided, hinged at one of its ends  18  to the body  11  and in one of its intermediate positions  19  to the stem  20  of a first piston or plunger  21 , sliding in a chamber  22  of a pump body  23 . In the rear wall of the chamber  22  a hole of inlet of the liquid  24  is formed, in communication with the interior of the container via a dipper tube  25 , and an outlet hole  26  in communication with the spray nozzle  16 , via a substantially L-shaped outlet duct  29 , comprising a vertical section  27  and a horizontal section  28 . 
         [0029]    The aforesaid inlet and outlet holes for the liquid  24  and  26  are occluded respectively by a dome piece  31  and by a truncated cone body  32  of a one-way suction and delivery valve  30 . 
         [0030]    In the internal side wall of the chamber  22 , on the side turned in the direction of the container wherefrom the dipper tube  25  takes the liquid, a hole or opening  43  is formed, suitable for allowing the reintegration of the air inside the container whereto the sprayer is connected, at each actuation of the pump. 
         [0031]    The functioning of the one-way valve  30 , described in greater detail in the aforementioned patent EP 1585602, is fairly intuitive. 
         [0032]    By pressing the trigger lever  17 , the liquid in the chamber  22  of the pump exerts a pressure against the valve  30 , deforming the truncated cone shank  32  and then exiting through the outlet hole  26  to go towards the nozzle  16 . 
         [0033]    When the trigger lever  17  is released and returns into the rest position through the action of elastic means not described, the plunger  21  creates a vacuum in the chamber  22  freeing the inlet hole  24 , as shown in  FIG. 2 , making the liquid aspirated from the container flow into the chamber  22 . 
         [0034]    What has been described hitherto is considered prior art from the aforementioned patent EP 1585602. 
         [0035]    According to the invention, the sprayer that is the object of the aforementioned European patent, as described hitherto, is equipped with a system of precompression of the liquid placed in the abovementioned outlet duct  29 . 
         [0036]    More particularly a widening and an extension upwards of the vertical section  27  of this duct are provided, such as to determine an advantageously cylindrical seat  40  open above, where it is closed by said closure cap  12  ( FIGS. 1-3 ). Positioned sealingly sliding inside the seat  40 , with a limited stroke, is a piston or plunger  41 , which will also be referred to as second piston in order to distinguish it from the piston  21  of the pump. 
         [0037]    Said advantageously cylindrical seat has a vertical passage  44 , positioned externally to the piston  41  and such as to place in communication the horizontal section  28  and the vertical section  27 , with said channel closed by means of the piston  41  (see the detail of  FIG. 6 ). 
         [0038]    Against the piston  41  acts an elastic element, in particular a spring  42 , which abuts against the aforementioned closure cap  12 , in order to push constantly downwards the piston  41 , in occlusion of the vertical section  27  of the outlet duct  29 . 
         [0039]    The piston  41  and the spring  42  can be made as separate parts but advantageously are formed in a single part through injection moulding of elastomeric or plastic materials, configuring the part  42  in such a way that it has the necessary elastic properties. 
         [0040]    When the pressure of the fluid which acts on the base of the piston  41  via the vertical section  27  of the outlet duct  29  overcomes the elastic force of the spring  42 , the piston  41  rises slightly, allowing the passage of the fluid in the horizontal section  28  via the vertical passage  44  as far as the delivery nozzle  16  which will be in the open position, as schematised in  FIG. 3 . 
         [0041]    According to an alternative embodiment, illustrated in  FIG. 4 , the seat  40  for housing of the piston or plunger  41  is closed above by means of a plug  45  stabilised in said seat by means of a threaded connection or of an undercut or in another known and suitable way. 
         [0042]    According to a further alternative embodiment, illustrated in  FIG. 5  and in the detail of  FIG. 6 , the assembly defined by the piston or plunger  41  and by the spring  42  is stabilised in the seat  40  by means of an annular edge  46  developed along the internal circumference of the housing seat  40  and at its upper end opposite to the vertical section  27 ; the upper part of the spring  42 , as schematised in  FIGS. 5 and 6 , goes to abut with the lower portion of said annular edge. 
         [0043]    The functioning of the sprayer with precompression system will now be described, taking account of what has already been said previously about the functioning of the sprayer in itself. 
         [0044]    On the first actuation of the trigger lever  17 , with the nozzle  16  in open position, the plunger  21  pumps the air contained in the chamber  22  towards the vertical section  27  of the outlet duct  29 . After some actuations the pressure in the duct  27 , by acting on the base of the piston  41 , causes the rising thereof in its seat  40  in contrast to the action of the precompression spring  42 , thus opening the vertical passage  44  and placing in communication the duct  27  with the horizontal section  28  of the outlet duct  29  via which the air flows in order to exit from the nozzle  16 . By continuing to actuate the trigger lever  17 , liquid is primed from the container through the dipper tube  25  and pumped towards the outlet duct  29 . The liquid which cannot be compressed will cause the raising of the piston  41 , as mentioned previously, and at the same time the spring  42  will exert constantly a force in the opposite direction, creating an additional pressure on the liquid in the horizontal channel  28 , which will have a greater speed or acceleration in output from the nozzle  16 . 
         [0045]    It should be noted that the constant force exerted by the precompression spring  42  on the piston  41  also allows a rapid closure of the channel  28  supplied by the piston  41  which continues to push the liquid outwards. 
         [0046]    The practical effect obtained with the system of precompression according to the invention is that in any way the trigger lever  17  is actuated, as a hypothesis also slowly and/or partially, in any case a nebulisation of the liquid is obtained at the outlet of the nozzle  16 , as schematically shown in  FIG. 3 , thanks to the pressure exerted thereon by the precompression spring  42 , which would not occur in a sprayer not provided with system of precompression. 
         [0047]    In  FIGS. 2 and 3  the arrows indicate the passage of the fluid according to the position of the trigger lever  17 . 
         [0048]    In the embodiment illustrated, the outlet channel  29  has an L configuration, with the two sections  27  and  28  orthogonal one in relation to the other and the horizontal section  28  parallel to the chamber of the pump  22 . 
         [0049]    It is however clear that the two sections  27 ,  28  of the outlet duct  29  can be differently angled one in relation to the other, just as the chamber of the pump  22  could be tilted with respect to said sections  27 ,  28 . 
         [0050]    Naturally the invention is not limited to the particular embodiment previously described and illustrated in the accompanying drawings, but instead numerous detail changes can be made thereto, within the reach of the person skilled in the art, without thereby departing from the scope of the same invention as defined in the annexed claims.