Abstract:
A toy water gun includes a reservoir for storing liquid, a firing chamber, a nozzle extending from the firing chamber, a valve for closing off the nozzle, a firing piston in communication with the firing chamber and biased by a spring to diminish the volume of the firing chamber, a pump receiving liquid from the reservoir and delivering same under pressure to the firing chamber whereupon the firing piston moves against the firing spring, and a trigger connected with the valve so as to open the valve to eject liquid contents of the firing chamber under pressure through the nozzle.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to toy water guns. More particularly although not exclusively, the invention relates to a pressurised toy water gun that provides an instantaneous and continuous water jet. 
         [0002]    Known toy water guns include a hand-activated reciprocating pump mechanism for pumping air into a pressure storage device. It is necessary that the hand pump be activated repeatedly immediately upon commencement of firing. This can delay gameplay and unnecessarily tire the user. 
       OBJECTS OF THE INVENTION 
       [0003]    It is an object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and/or more generally to provide an improved toy water gun. 
       DISCLOSURE OF THE INVENTION 
       [0004]    There is disclosed herein a toy gun comprising:
       a reservoir for storing liquid;   a firing chamber;   a nozzle extending from the firing chamber;   a valve for closing off the nozzle;   a firing piston in communication with the firing chamber;   a firing spring biasing the firing piston in a direction to diminish the volume of the firing chamber;   a pump receiving liquid from the reservoir and delivering same under pressure to the firing chamber whereupon the firing piston moves against the spring;   a trigger connected with the valve so as to open the valve to eject liquid contents of the firing chamber through the nozzle under pressure.       
 
         [0013]    Preferably, the pump comprises a reciprocating priming piston and an inlet connected via a conduit to the reservoir and an outlet connected via a conduit to the firing chamber. 
         [0014]    Preferably, the valve includes a valve stem extending along an axis of the nozzle. 
         [0015]    Preferably, the firing spring is a coil spring having a longitudinal axis that is common with that of the nozzle. 
         [0016]    Preferably, the valve stem passes through the firing piston. 
         [0017]    Preferably, the toy gun further comprises a valve closing spring surrounding the valve stem and biasing the valve into a closed position. 
         [0018]    Preferably, the toy gun further comprises a valve opening spring surrounding the valve stem behind the firing piston. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: 
           [0020]      FIG. 1  is a schematic cross-sectional elevation of the major working components of a toy gun, 
           [0021]      FIG. 2  is a schematic cross-sectional elevation of the firing cylinder of the toy gun in a low pressure state, 
           [0022]      FIG. 3  is a schematic cross-sectional elevation of the firing cylinder in an energised state, 
           [0023]      FIG. 4  is a schematic cross-sectional elevation of the firing cylinder at commencement of trigger activation, 
           [0024]      FIG. 5  is a schematic cross-sectional elevation of the firing cylinder immediately after the trigger has been squeezed, 
           [0025]      FIG. 6  is a schematic cross-sectional elevation of the firing cylinder as the firing piston commences forward movement to eject liquid from the firing chamber through the nozzle, 
           [0026]      FIG. 7  is a schematic cross-sectional elevation of the firing cylinder as liquid is being ejected through the nozzle, 
           [0027]      FIG. 8  is a schematic cross-sectional elevation of the firing cylinder with the firing piston in the same position as shown in  FIG. 7 , but where the priming mechanism is activated continuously during firing to maintain a flow of liquid into the firing chamber and through the nozzle, 
           [0028]      FIG. 9  is a schematic cross-sectional elevation of the major working components of another toy gun having an alternative firing cylinder and firing piston configuration, with the hydraulic diverter omitted from the drawing, 
           [0029]      FIG. 10  is a schematic cross-sectional elevation of yet another toy gun arrangement having a further alternative firing cylinder and firing piston configuration, with the hydraulic diverter omitted from the drawing, and 
           [0030]      FIG. 11  is a schematic cross-sectional elevation showing the internal components of the hydraulic diverter forming part of the toy gun. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    In  FIGS. 1 to 8  of the accompanying drawings the major components of a toy gun  10  are depicted schematically. The toy gun body is omitted from the drawings as the body can take on any desired shape and configuration. 
         [0032]    The gun  10  includes a water reservoir  11  having a screw cap  12  upon its filling opening. The screw cap  12  has an air vent  13 . Extending from a drain point of the reservoir  11  is a conduit  29 . This attaches to the inlet  25  of a hydraulic diverter  24 . A bypass  47  from the inlet  25  to the hydraulic diverter  24  includes a relief valve  26  as depicted. The internal structure of the hydraulic diverter  24  it depicted in  FIG. 11 . 
         [0033]    Extending from the body of the hydraulic diverter  24  and attached thereto at attaching flange  46  is an elongate priming cylinder within and from which a reciprocating priming piston  22  extends. A priming piston  22  is mounted at the proximal end of a priming rod  23 . The distal end of the priming rod is provided with a handle  21 . 
         [0034]    The hydraulic diverter  24  includes an outlet  30  to which another conduit  31  is attached. The other end of the conduit  31  is affixed to an inlet  38  of a firing cylinder  34 . 
         [0035]    The firing cylinder  34  has located within it a reciprocating firing piston  33  having a sealing o-ring  37  extending thereabout and in sealing engagement with the inner cylindrical wall of the firing cylinder  34 . 
         [0036]    Forward of the firing piston  33  is a firing chamber  42  into which the inlet  38  delivers liquid from the hydraulic diverter  24 . 
         [0037]    A valve  19  seals against a valve seat defined by the back edge of the nozzle  20 . The valve  19  is fixed upon a valve stem  35  that extends along the axis of the nozzle  20 , through the firing piston  33  at which there is provided a sliding seal  43  and preferably through an opening in an end cap  39  at back end of the firing cylinder  34 . 
         [0038]    The end cap  39  is threaded or otherwise secured to the firing cylinder  34  and retains a firing compression coil spring  16  against the back of the firing piston  33 . The valve stem  35  extends through the centre of the firing spring  16  along its axis. Immediately behind the valve  19  is a short light valve closing spring  18  that serves to press the valve  19  against the valve seat when the firing piston  33  is in the forward position as depicted in  FIG. 2 . This complements the forward force applied by the hydraulic pressure of any liquid within the firing chamber  42  in maintaining the valve  19  closed. 
         [0039]    A firing piston buffer  40  is provided in the firing chamber  42  to limit the extent of forward movement of the firing piston  33 . Also surrounding the valve stem  35  is a long valve opening spring  32 . This bears in compression against a stopper  41  that is fixed upon the valve stem  35 . 
         [0040]    Mounted at a convenient location upon the toy gun body is a firing trigger  27 . The tail end of the link  14  passes through an aperture in a connecting tag  48  of the firing trigger  27 . There is a small pulling lug  15  fixed at the tail end of the link  14  against which the back face of the connecting tag  48  bears to draw the link  14  back when the trigger  27  is squeezed in use. This sliding arrangement allows the pulling lug  15  to separate from the connecting tag  48  so that the valve stem can bounce backward (faster/further than the trigger) after the trigger is squeezed. A trigger spring  28  biases the trigger  27  forward and serves to return the trigger to its rest position after it is released. 
         [0041]    In use and prior to pulling the trigger, the pump handle  21  is activated just once or twice so that the hydraulic diverter  24  forces liquid from the reservoir into the firing chamber  42  so that the firing piston  33  moves backwards from the position depicted in  FIG. 2  against the force of the firing spring  34  to the position depicted in  FIG. 3 . During the low-pressure phase, the valve  19  is sealed in part by closing spring  18  against the valve seal at the back of the nozzle  20 . The closing spring  18  helps to seal the valve, but once piston  33  moves backward, the closing spring has no effect because it moves away from the front of the piston and any sealing force is provided solely by hydraulic pressure. 
         [0042]    Once the firing piston  33  has moved to its backmost position, any further reciprocation of handle  21  will result in opening of relief valve  26  and the return of over-pumped liquid to the conduit  29 . Such bypassing discontinues only when pumping ceases or the trigger  27  is squeezed. 
         [0043]    As shown in  FIG. 4 , nothing is emitted from the nozzle  20  until the trigger  27  is squeezed to draw the link  14  and valve stem  35  away from nozzle  20  as shown in  FIGS. 5 and 6 . 
         [0044]    Irrespective of whether the firing chamber is full of liquid or otherwise, the pulling force on the valve stem by the trigger will open the valve  19  immediately. The pulling force to release/open the valve must exceed the combined hydraulic force on the back of the valve minus the spring force applied by valve opening spring  32 . Once this threshold is exceeded, the valve  19  will rapidly bounce away from the nozzle  20  by action of the valve opening spring  32 . Energy stored in the firing spring  16  then pushes the piston  33  rapidly forward so that liquid is emitted past valve  19  through the nozzle  20 . If the player does not pump the handle  21 , the jet of water from nozzle  20  ceases when the firing piston  33  has reached the buffer  40  and the valve  19  has returned to its rest/closed position. The pump handle  21  can be repeatedly and continuously reciprocated to draw liquid from the reservoir  11  and deliver it to the firing chamber for dispatch through the nozzle  20  under pump action of the priming piston. 
         [0045]    It will be understood that the hydraulic diverter  24  has two strokes—namely a pumping stroke and a suction stroke. During the pumping stroke, liquid flows into the firing chamber  42 . During the suction stroke, no liquid flows into the firing chamber and as such the firing piston  33  will move forward. By correctly calibrating the nozzle dimensions to the pump throughput, a continuous flow of liquid from the nozzle  20  can be achieved upon reciprocation of handle  21 . 
         [0046]    Referring to  FIG. 11 , the pumping action will further be described with reference to the internal structure of the hydraulic diverter  24 . As mentioned earlier, the priming cylinder is attached to the hydraulic diverter at attachment flange  46 . Immediately behind the attachment flange  46  is an outlet valve  45 . When the priming piston  22  moves toward the hydraulic diverter  24  (the pumping stroke), the outlet valve  45  opens to allow the passage of water through outlet  30 . There is an inlet valve  44  closing a passage between the inlet  25  and the attachment flange  46 . As the priming piston moves toward the hydraulic diverter  24 , the inlet valve  44  is forced closed so that all the liquid between the inlet valve  44  and priming piston  22  passes through the outlet valve  45 . When the priming piston  22  is drawn away from the hydraulic diverter  24  (the suction stroke), the outlet valve  45  closes and at the inlet valve  44  opens to allow liquid to be drawn in from reservoir  11 . 
         [0047]    When the user ceases reciprocation of the handle  21 , the firing piston  33  will returned to the position depicted in  FIG. 3  and any further pumping will simply result in a back flow of water through the relief valve  26  as described earlier. 
         [0048]    The embodiments depicted in  FIGS. 9 and 10  function in the same manner as described above. These embodiments  90  and  100  illustrate examples in which the valve stem  35  need not extend through the firing piston  33 . In  FIG. 9 , the firing cylinder  34 ′ depends from the firing chamber  42 , whereas in  FIG. 10 , the firing cylinder  34 ″ is positioned above the firing chamber  42 . In neither embodiment does the valve stem  35  extended through the firing piston  33 . As such, a seal (like  43  in the preceding embodiment) can be omitted. 
         [0049]    It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, rather than providing a linearly reciprocating piston rod and priming piston  22 , the hydraulic diverter  24  could be activated by a pivotally reciprocating handle attached to internal rotary pump parts.