Apparatus for automatically operating the discharge valve of a pressure container
BACKGROUND OF THE INVENTION 
     This invention relates to an apparatus for automatically operating the discharge valve of a pressure container for dispensing liquid or vapour products contained in the pressure container. 
     Various types of apparatus designed to dispense certain products contained in pressure containers are commercially known. All these devices have as a common general characteristic the fact that they have an outer casing usually provided with a discharge hole through which the product is discharged and it is known to operate the nozzle of the container by means of an apparatus provided with a driving mechanism housed within the casing. These mechanisms consist of an electric motor usually fed with electrical current from batteries and means for transmitting the movement of the motor to a drive element for operating the dispensing nozzle of the container. 
     The devices actually in use present multiple disadvantages which, in some way, affect the operation of the devices, to the detriment of consumption, control and/or life of the apparatus itself. Thus, there is a wide range of devices which do not have any control media, whereby the use in the unit of different types of existing pressure containers poses a real problem, due to the different heights of the dispensing nozzles, consequently limiting their use only to certain types of containers. 
     Other known devices use, as a drive member for operating the nozzle a lever or cam, with a predetermined fixed throw which, due to the different heights of the dispensing nozzles, force the motors in the majority of cases to exert great efforts at the time product is dispensed, against the elasticity of the material itself, with a high electrical current consumption and the resulting premature exhaustation of the feed batteries. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided an apparatus for automatically operating the discharge valve of a pressure container for automatically dispensing liquid or vapour products contained in the pressure container. The apparatus includes a drive shaft arranged to be driven by an electric motor controlled by a timing device, such shaft being drivingly connected to a speed reduction unit including a plurality of meshing toothed wheels, the last of the toothed wheels having connected thereto an eccentric which co-operates with a roller provided on one arm of a pivotable elbow lever, such one arm being connected to a spring which urges the lever towards a position where the free end of the other arm of the elbow lever presses on the discharge valve/nozzle of the pressure container. 
     The apparatus of the present invention could be defined, with regard to existing apparatus, as one having an &#34;inverse&#34; operation, since in the known devices the pressure exerted on the dispensing nozzle of the container, whether by means of a cam or a lever, is carried out by the operation of the motor while this is taking place. However, in the device of the invention, the pressure is exerted by the recovery action of a spring on an appropriate lever, so that during the greater part of the operating cycle the basic function of the motor is to move the actuating lever to its starting position, progressively and counter to the action of the spring. 
     The unit has been formed starting from an appropriate motor from which movement is transmitted by means of an appropriate belt, preferably silicone to avoid noises, to a speed reducer set, formed by toothed wheels. The last toothed wheel has, conjunctively and integrally with its axle, an eccentric of suitable characteristics. The unit also has an elbow lever for actuation of the dispensing nozzle by one of its arms, the lever being capable of turning in relation to a mounting bearing, with an appropriate spring fitted to an opposite arm of the lever. Lastly, the eccentric is provided with an appropriate boss or pin for the operation of a current interruptor switch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing in which the single figure is an elevational view of the various elements of the apparatus according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawing, the apparatus has a driving axle 1 which, by means of a belt 2 transmits movement to a speed reduction gear unit formed by toothed wheels 3, 4 and 5. The toothed wheel 5 has an axle provided with an eccentric cam 6 having a boss or pin 7 for the actuation of a switch formed by metallic fingers 8 and 9. 
     Adjacent to the toothed wheel 5 there is an elbow or L-shaped lever 10 which is rotatably mounted by a bearing 11 about which it can rotate. The upper end of the lever 10 is secured to a spring 2 with appropriate characteristics, the lower end of the lever 10 is free, and it is this end whch operates a dispensing nozzle 13 of a container 14 which contains the pressurized product that is to be dispensed. The spring 12 is secured at its opposite end to the frame (not shown) which contains the apparatus and container. 
     The lever 10 is provided with a roller 15, capable of rotating in relation to its mounting point, located in a position facing the eccentric 6. 
     In the interior of the frame will also be included other elements such as an electric motor 16 and a conventional-type timer device 17 which will transmit electrical current pulses to the motor and provided with means for time control that has to elapse between every two consecutive impulses. 
     Having described the various component parts of the apparatus of the invention, the operation thereof now will be described, starting from the rest position shown in the drawing. Thus, in the drawing the spring 12 is illustrated in its stretched position. 
     When the electric 16 receives an electrical impulse from the timer 17, the shaft 1 connected to its rotor is thereby rotated, transmitting this movement to the toothed wheel 3 by means of the belt 2 and from the toothed wheel 3 to the toothed wheel 5, by means of the toothed wheel 4. The eccentric 6 which is connected to the axle of the wheel 5, will change its position, whereby elbow lever 10 at this time will start moving, as the force of the spring 12 will urge it to rotate anti-clockwise about the bearing 11, so that the lower free end of lever 10 will then apply pressure on the nozzle 13, forcing it downwards and thereby releasing the product contained in the container 14. Simultaneously, the boss or pin 7, in changing its position by moving with the eccentric 6, will have released the switching element 9, which then comes into contact with element 8, thereby maintaining the electric current supply to the electric motor 16 to maintain operation thereof. 
     When the eccentric 6 continues to rotate, it will cause the roller 15 to move back slowly and the lever 10 will move along with it, thus overcoming the tension of spring 12, so that when eccentric 6 has made one complete revolution and, therefore, completed one cycle, the apparatus will then be exactly in the same starting position shown in the drawing. The boss or pin 7, will make one full turn with the rotation of the eccentric 6, so that when the cycle has been completed, pin 7 again will come into contact with the switch element 9, moving it away from element 8, and thus cutting off the flow of electric current to the motor 16 and discontinuing the movement until a new impulse is generated by the timer 17. 
     The control of the quantity of the product to be dispensed for each operation will be determined by the internal control of the aerosol itself. 
     On the other hand, the height at which the free end of the elbow lever 10 is positioned permits its use with containers with different heights of their dispensing nozzles 13, within prescribed limits. 
     The apparatus thus formed is exceedingly simple, compact and noise-free during operation, and does not require any subsequent maintenance operation.