This invention relates to a liquid detergent and additive metering and distributing device for a washing machine, particularly for a laundry washing machine for domestic use.

Already known are laundry washing machines provided with a liquid detergent and additive distributor, comprising a reservoir for containing said liquids disposed in the lower portion of the machine and associated with at least one metering chamber located therebelow and connected thereto through automatic valve means adapted to permit or to interrupt the gravity flow of said liquids from the reservoir to the metering chamber. The latter is subdivided into two hermetically separated compartments by means of a flexible diaphragm. One compartment is connected to the tub of the washing machine, whilst the other is connected to the tub and to the water supply circuit, respectively so as to be intermittently filled and emptied for displacing metered quantities of the liquids towards the tub. The operation of this known metering and distributing device is thus accomplished by means of hydraulically actuated control means. Although the described device operates satisfactorily, it presents structural complications in that it requires a three-way valve and an additional conduit for the water supply as well as a hermetically closed separation by a diaphragm for providing the two separate compartments within the metering chamber. Said three-way valve and/or said diaphragm are liable to cause malfuncions due to wear during long-time use.

On the other hand, this embodiment does not allow for suitable utilization of the free jet section customarily required for safety reasons.

It is an object of the present invention to provide a liquid detergent and additive metering distributor for a washing machine which avoids the possible inconveniences of the hydraulically operated system by making use of a free jet section provided in the machine for obtaining the metering of said liquids and the introduction thereof into the tub by pneumatic actuation.

In view of this object, the invention provides a distributor device comprising a reservoir disposed in the lower portion of the machine and associated to at least one metering chamber located therebelow, the connection between said reservoir and said chamber being adapted to be closed by automatic vlave means, said chamber being connected to the tub of the washing machine.

According to the invention, a device of this type is characterized in that said metering chamber is connected to an air chamber provided with automatic valve means and associated to a free jet section connected to the water supply circuit.

The characteristics of the invention will become evident from the following description of an exemplary and nonlimiting embodiment with reference to the accompanying drawing.

The drawing shows in diagrammatic form a conventional laundry washing machine comprising a washing tub 1, connected to which is the outlet of a detergent powder distributor 2 supplied with water from the water mains 3 through a solenoid valve 4, a free jet section 5, and a conduit 6.

Disposed in the lower portion of the machine is at least one reservoir 7 for containing liquid detergents and additives, said reservoir 7 containing a metering chamber 8.

The latter is connected to reservoir 7 through an automatic valve and is additionally connected to distributor 2 through a conduit 10.

Metering chamber 8 is further connected to an air chamber 13 associated with free jet section 5 through a further conduit 11 and an automatic valve 12. Air chamber 13 is also provided with an automatic venting valve 14.

The operation of the described device appears simple and evident. When the machine is at rest, or during operating phases which do not require the introduction of liquid detergents or additives into the tub, valve 9 is open, and metering chamber 8 is filled with a metered quantity of the liquid from reservoir 7. In this situation, air chamber 13 is not under pressure, and valves 12 and 14 are open. If it is required to introduce the metered liquid into the tub, the program unit (not shovm) of the machine causes the water supply valve to be opened, so that the water from the water mains fills air chamber 13 via free jet section 5.

The pressure generated thereby within air chamber 13 causes venting valve 14 to close instantly, so that the air contained in chamber 13 is displaced towards metering chamber 8 through valve 12 and conduit 11.

The pressurized air causes valve 9 to close and the liquid contained in metering chamber 8 to be displaced towards washin.g tub 1 through conduit 10 and distributor 2.

After the water has completely filled air chamber 13, valve 12 is closed by the hydraulic pressure to prevent the water from entering conduit 11 and flowing into metering chamber 8.

Subsequently the water supplied from water mains 3 and passing through free jet section 5 is introduced into washing tub 1 through conduit 6 and distributor 2 for completeing the required charge for the following washing or rinsing phase.

As soon as the water supply from the water mains stops, chamber 13 is emptied, whereupon valves 12 and 14 open.

This results in a partial vacuum within metering chamber 8, causing valve 9 to open so as to admit a further metered quantity of the liquid detergent or additive into chamber 8.

According to the invention, the metering of the liquid and the introduction thereof into the tub are thus accomplished by substantially pneumatic actuation, reducing to a minimum the number of components which are moreover of extreme simplicity and reliability.

The device according to the invention permits the eventual problem of regulating the metered quantities of liquids to be solved in a simple manner. To this effect, the immersion depth of conduit 10 into chamber 8 may be varied by employing a sliding sleeve 15 at the inflow end of conduit 10.

Sleeve 15 is vertically displaceable by means for instance of a pull rod 16 actuated by a lever or control knob 17 mounted at the front of the machine.

The device according to the invention thus accomplishes the stated objects and provides the additional advantage that the liquids employed may be metered with high accuracy independent of their density and viscosity.