Abstract:
A pressure gauge device for a toy water gun having a pressure chamber, includes a housing, a light source mounted to the housing, a coloured transparency mounted movably to the housing, a pneumatic actuator communicating with the chamber and moving the transparency, and a display receiving light from the light source that has passed through the transparency.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to pressure gauges. More particularly, although not exclusively, the invention relates to a pressure gauge for a toy water gun. 
     Some “high-powered” toy water guns have a pressurised water chamber. A single held-down depression of a trigger will result in a continuous stream of water being ejected from the gun&#39;s nozzle until such time as water in the chamber is depleted or air pressure in the chamber egualises with the ambient atmospheric pressure. Air pressure is increased in the chamber by a manually reciprocal pump action device. 
     Is it known to provide a convenient pressure gauge on such toy water guns to display the air pressure within the chamber. The known device comprises a pivotally mounted needle upon a dial or face. The shaft from which the needle extends has a pinion gear in mesh with a moving rack in turn associated with a spring-loaded plunger connected pneumatically with the chamber. 
     Such a pressure gauge, although useful during daylight hours is of little use at night time when children might be playing “war games” in the dark. 
     OBJECTS OF THE INVENTION 
     It is an object of the present invention to overcome or substantially ameliorate the above disadvantage and/or more generally to provide an alternative pressure gauge, useful in toy water guns or other applications including toys. 
     DISCLOSURE OF THE INVENTION 
     There is disclosed herein a pressure gauge device for a toy having a pressure chamber, the device comprising: 
     a housing, 
     a light source mounted to the housing, 
     a coloured transparency mounted movably to the housing, 
     a pneumatic actuator communicating with the chamber and moving the transparency, and 
     a display receiving light from the light source that has passed through the transparency. 
     Preferably the transparency is a multi-coloured disk. 
     Preferably the disk is mounted upon a shaft. 
     Preferably the shaft has a pinion gear mounted thereon and the pneumatic actuator has a spring-biased plunger having a rack moving therewith and in mesh with the pinion gear. 
     Preferably the display comprises a number of light-transmissive tubes extending from alongside the transparency. 
     Preferably the housing includes a back part to which the light source and disk are mounted, an intermediate part adjacent to the transparency, and a front part including the display. 
     Preferably the pneumatic actuator is mounted to the back part externally of the device. 
     DEFINITION 
     As used herein, the term “transparency” is intended to mean something that transmits light and affects the light in some way. It is not necessarily transparent, as it is most likely translucent at least in part. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred form of the present invention will now be described by way of example with reference to the accompanying drawings, wherein: 
     FIG. 1 is a schematic partially cross-sectioned side elevational view of a toy water gun, 
     FIG. 2 is a schematic perspective illustration of a pressure gauge, 
     FIG. 3 is a schematic cross-sectional illustration of the pressure gauge of FIG. 2 taken at III—III in FIG. 2, 
     FIG. 4 is a schematic perspective illustration of a pneumatic actuator, 
     FIG. 5 is a schematic cross-sectional illustration of the pneumatic actuator of FIG. 4 taken at V—V in FIG. 4, 
     FIG. 6 is a schematic parts-exploded perspective illustration of the pressure gauge of FIG. 2, 
     FIG. 7 is a schematic rear perspective partially parts-exploded perspective illustration of the pressure gauge of FIG. 2, and 
     FIG. 8 is a schematic rear perspective illustration of the pressure gauge of FIG.  7 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 of the accompanying drawings there is schematically depicted a toy water gun  10 . Water gun  10  includes a chamber  11  that receives water via a cap  12 . The chamber  11  can be pressurised upon reciprocal movement of a pumping piston  13  in a known manner. A trigger  14  can be depressed and held down to result in ejection of squirted water via nozzle  15 . Trigger  14  opens a valve to allow pressure within chamber  11  to force water through the nozzle  15  in a known manner. 
     A pressure-indicating gauge  16  is mounted to the side of the toy gun  10  forward of the trigger  14 . Components of the pressure gauge are illustrated in the remaining drawing figures. 
     The pressure gauge  16  includes a housing made up of a back part  17 , an intermediate part  18  and a front part  19 , all of which are typically fabricated from moulded plastics material. 
     The back part houses a light globe  20  receiving current from a battery (not shown) via a pair of electrical conductors  21  and a switch (also not shown). The battery would be housed somewhere within the toy gun  10  and the switch would he somewhere on the toy gun exterior or on the pressure gauge itself. 
     The back part  17  includes an integral bushing  22  through which a shaft  23  extends. A pinion gear  24  is fixed to an externally projecting end portion of the shaft  23 , whereas a transparency disk  25  is mounted to the other end portion of the shaft behind the intermediate housing portion  18 . A wall  26  of the intermediate portion includes a blind hole  27  to support an end of the shaft  23 . The intermediate portion  26  also includes a number of apertures  28  as shown in FIG.  6 . 
     The front part  19  includes a display area  28  also having a number of apertures  29  therein. Situated within or behind the front part  19  are a number of light tubes  30 , either formed individually as shown or as an integral moulding. Each tube is made of substantially clear moulded plastics material, or might be translucent or otherwise light-transmissive. Narrow back ends  31  of the light tubes  30  are received within the apertures  28  of the intermediate part  18  whereas wider front portions  32  pass into, adjacent, or completely through apertures  29  in the front part  19 . The transparency disk  25  is divided into a number of segments  33 ,  34  and  35 . These might typically be tinted red, green and yellow in a clockwise sense The disk  23  is fixed to the shaft  27  as is the pinion gear  24   
     The housing parts  17 ,  18  and  19  a typically glued together or otherwise substantially sealed. 
     As shown in FIG. 8, the back part of the housing  17  has a pair of mounting brackets  36  onto which a pneumatic actuator  37  is mounted. This mounting can be by way of screws (not shown) that extent outwardly through holes  42 . The pneumatic actuator  37  is a known component and includes a rack  38  attached to an internal plunger  39 . The plunger  39  is biased by compression spring  40 . A pneumatic line  43  (FIG. 1) extends from a socket  41  on the front of the actuator to the chamber  11 . The pneumatic line can be clamped about the O-ring seal  44 . 
     When the chamber  11  is pressurised by reciprocal actuation of the pumping piston  13 , pressure increases in the chamber  11  and therefore also in the pneumatic line  43  and pushes the actuator plunger  39  backwards against the force of spring  40 . As a result, the rack  38  moves backwards and causes rotation of the pinion gear  24  and the transparency disk  25 . If the light globe  20  is switched on, light passing through the light tubes  30  will change colour upon rotation of the disk  25  so that the colour displayed at the front of the various light tubes in the display area  28  will change from aperture-to-aperture  28 . As pressure within the chamber  11  diminishes upon depletion of water therefrom, this will be apparent to the user by the colours displayed in the display area  28 . 
     It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as the beyond the scope of the present invention. For example, instead of providing a rotatable disk  25 , a straight transparency strip could be attached directly to a plunger  39 , instead of providing a rack and pinion arrangement.