Abstract:
An operating pushbutton for dispensing pumps for fluid substances contained in containers on which the pumps are mounted. The pushbutton has an end portion which can translate on a portion thereof applicable to the pump stem, such that when a pressure is exerted on said end portion it undergoes a free translation before causing the other pushbutton portion to move, hence preventing accidental dispensing of the fluid substance.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a safety pushbutton for operating fluid substance dispensing pumps.  
         [0003]     2. Discussion of Related Art  
         [0004]     To controlledly dispense fluid substances (in particular liquid or creamy substances), it is known to use valves or pumps mounted on the mouth of containers in which the substances are contained, either under or not under pressure. Such pumps or valves have a hollow stem projecting out of the respective container and a pushbutton or cap which is mounted on the free end of the stem and has a nozzle or hole through which the fluid substance can be dispensed to the outside of the container following axial translation of the pushbutton. When the pump is in its rest condition there is no flow of fluid substance from the nozzle of the pushbutton. When pressure is exerted (usually with a finger of one hand) on the free end of the pushbutton, this moves axially together with the stem on which it is mounted, hence operating the pump or valve and dispensing the fluid substance. Even small movements of the pushbutton away from its rest position cause the substance to emerge from the container in which it is held, this in many cases representing an important drawback. For example, if the substance is a perfume or a deodorant, it is often held in a small container which can be carried in the user&#39;s handbag: the user (in this case generally a woman) may inadvertently exert a small pressure on the free end of the container when inserting a hand into the handbag, with the result that the pushbutton moves slightly away from its rest position, to cause undesired dispensing of the substance. A similar undesired dispensing of the fluid substance can occur if, after being filled, the containers are positioned one on another (for example packaged in boxes in which the containers may be positioned on several levels) to facilitate their transport and storage: a temporary axial force may be transmitted to the free end of the pushbuttons of those containers lying at lower levels (for example as the result of impacts received by the boxes used to transport them), resulting in a small movement or oscillation which can cause undesired dispensing of fluid substance.  
         [0005]     To reduce this drawback, pumps have been produced in which the stem can be moved away from its rest position through a limited distance without the fluid substance emerging. Pumps of this known type have a complicated and costly structure: one of these is described for example in U.S. Pat. No. 3,583,605.  
       SUMMARY OF THE INVENTION  
       [0006]     The main object of the present invention is to provide a safety pushbutton which can be mounted on the free end of the stem of any pump or valve of known type and prevents dispensing of fluid substance when the free end of the pushbutton undergoes, away from its rest position, a movement (generally of a small extent) which is less than an amount determined during the design and manufacture of the pushbutton.  
         [0007]     A further object is to provide a pushbutton of the aforesaid type which is of low production cost and has a simple structure of reliable operation.  
         [0008]     These and other objects are attained by a safety pushbutton applicable to the stem of a pump or valve for dispensing fluid substances, characterised by comprising two separate portions, namely a free end portion and, respectively, a main portion in which there are provided a seat for the free end of said stem and a nozzle for the exit of fluid substance originating from said seat, to which the nozzle is connected by a conduit provided in the main portion of the pushbutton, said end portion being movable relative to the main portion of the pushbutton, on which it is retained by retention elements which hold together these two pushbutton portions, between which there is interposed an elastically deformable element which urges the free end portion away from the main portion of the pushbutton towards and against said retention elements. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The structure and characteristics of the safety pushbutton will be more apparent from the ensuing description of one embodiment thereof given by way of non-limiting example with reference to the accompanying drawing, in which  
         [0010]      FIGS. 1, 2  and  3  are partly sectional side elevations of a safety pushbutton in three successive positions between its rest position and its dispensing position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]     The figures show schematically a pump  1  (of any known type) mounted on the mouth of a container  2  by means of a ring cap  3 ,  4 . From the upper end  4  (with respect to the drawing) of the ring cap  3 ,  4  there projects the stem  5  of the pump  1 ; the container  2  contains (in known manner, not shown for simplicity) a fluid (liquid or creamy) substance which is fed into the pump  1  by a dip tube, not shown in the drawings as it is of usual type well known to the art.  
         [0012]     When the pump is operated, the fluid substance originating from the pump  1  is expelled to the outside through a dispensing nozzle of a pushbutton  6  mounted on the free end of the stem  5  and operable by a finger of one hand pressing on the free end (the upper end with respect to the figures) of the pushbutton. The present invention relates to the structure and operation of the pushbutton  6 ,  7  which, as will be apparent from the ensuing description, can be defined as a “safety pushbutton”. This pushbutton comprises two separate portions, namely a main portion  6  and a free end portion  7 .  
         [0013]     The main portion  6  is shown in front view and has substantially the form of a pushbutton of any known type, it comprising a nozzle  8  (for expelling the fluid substance from the container  2  to the outside environment) which, by means of a conduit, not shown but also of a type known in the art, is connected to a seat (also not shown in the drawing) in which the free end of the stem  5  of the pump  1  is sealedly inserted.  
         [0014]     The free end portion  7  of the safety pushbutton is shown in axial section in the figures and has substantially the form of a disc  9  from which there projects a tubular skirt  10  (or a plurality of separate appendices) having at its free end a series of inwardly projecting teeth  11  (or a continuous rib). The rib or teeth  11  interfere with a continuous rib  12  projecting outwards from the upper end of the pushbutton main portion  6  such that the disc  9  can rock about the portion  6  but cannot separate therefrom, this being prevented by the teeth or rib  11  which interfere with the projecting rib  12  (the desired result of allowing the two pushbutton portions to rock about each other but preventing their involuntary separation could evidently be achieved in other equivalent ways, for example by making teeth or a rib projecting from one of the two portions engage in a respective groove or recess provided in the opposing surface of the other pushbutton portion).  
         [0015]     As can be seen from the figures, there project from the lower surface of the disc  9  a plurality of inclined flexible appendices  13 , the free ends of which rest on the upper surface of the pushbutton main portion  6 , to maintain the disc  9  (and hence the end portion  7  of the pushbutton) raised from the upper surface of the pushbutton main portion  6  when the pump and the pushbutton are in their rest condition ( FIG. 1 ).  
         [0016]     When a pressure is exerted on the upper surface of the disc  9  with one finger, the flexible appendices  13  firstly flex and the disc  9  approaches the upper surface of the pushbutton main portion, without this operating the pump  1 : for this to happen, the elastic resistance of the appendices  13  to flexure must be less than the force required to operate the pump (which generally contains a spring tending to maintain it urged into its closed rest position).  
         [0017]     After a small initial free movement, the disc  9  (or a non-flexible element forming part of the end portion  7  of the pushbutton) comes into contact with the pushbutton portion  6 , as shown in  FIG. 2 . Starting from this position and continuing to press on the disc  9 , this continues to move downwards (with respect to the figures), but now causing the pushbutton portion  6  to move and hence the pump to operate, so dispensing the fluid substance through the nozzle  8 .  
         [0018]     The elastically deformable elements which tend to maintain the two pushbutton portions spaced apart can be different from the appendices  13  shown in the drawings: for example, they can consist of a metal spring or a different element. The pushbutton can be advantageously produced very easily and economically by moulding all its components from plastic material.  
         [0019]     From the description, it will be apparent that forces can be transmitted to the top of the free end portion of the pushbutton which cause it to undergo movements within values determined during production, without resulting in operation of the pump on which the pushbutton is applied.