Multi-dose dispenser of liquid additives for household appliances

Abstract

 A washing aid dispenser (2) communicates via a first normally open aperture (4) with a volumetric metering chamber (5) having a normally closed dispensing aperture (6).
Respective shutters (8, 9; 21, 22) are controlled to alternately open and close said apertures (4, 6) in such a manner as to deliver through said second aperture (6) pre-determined amounts of washing aid that are let into the metering chamber (5) through said first aperture (4). The shutters (8, 9; 21, 22) only open the second aperture (6) after they have closed the first aperture (4), and open again the first aperture (4) only after they have closed again the second aperture (6).

Description

[0001] The present invention refers to a multi-dose dispenser of liquid additive products for washing machines, in particular a dispenser of rinsing aid for dishwashing machines.

[0002] The need is largely known to exist in modern household dishwashing machines for a multi-dose kind of dispenser to be provided, which is capable of delivering into the washing vessel appropriately metered amounts of rinsing aid, which is usually in the form of a viscous liquid with a high foaming capacity, during different phases of a same operation cycle of the machine. For example, it is appropriate for a dose of rinsing aid to be dispensed not only during a rinsing phase preceding the final drying of the washload items, but also during the actual washing of the same washload items in view of improving the soil removal effect.

[0003] To such a purpose, the dispenser shall not only have a sufficient holding capacity to dispense an adequately high number of doses, but must also be capable of accurately metering each single dose of liquid additive. Accordingly, the dispenser must include a multi-dose reservoir for storing said adequate amount of liquid additive, as well as means adapted to repeatedly measure and deliver the same additive in the form of volumetrically metered amounts. The solution consisting in the rinsing aid being metered through a time-controlled delivery is in fact quite out of the question, since the density of the rinsing aid itself is strongly variable depending on the different operating temperatures and the different kinds of additive used.

[0004] On the other hand, since the loading door of the dishwashing machine cannot be opened during an operation cycle of the machine, such a volumetric metering cannot be accomplished by having resort to a traditional "decanting" or pouring-off system, i.e. by making use of a simple dispenser of the type that is mounted on the door of the machine and is adapted to decant, i.e. pour into a volumetric metering chamber, each time that the door of the machine is opened and closed again, a corresponding amount of rinsing aid stored in a multi-dose reservoir.

[0005] In an effort to reconcile these contrasting needs, the proposal has been made of providing the rinsing aid dispenser with a multi-dose rinsing-aid reservoir whose bottom is in communication, via a filling aperture, with a volumetric metering chamber situated therebelow, the bottom of which is in turn capable of communicating fluidly with the washing vessel of a washing machine via a dispensing aperture. A moving double-shutter member controlled by an electromagnet is adapted to be switched between a first and a second position, in which it shuts the sole filling aperture and the sole dispensing or delivery aperture, respectively.

[0006] In said first position, the liquid additive stored in the reservoir is allowed to flow by gravity to fill said metering chamber, whereas in said second position the amount of liquid additive contained in the metering chamber is allowed to be dispensed, i.e. delivered into the washing vessel, by gravity.

[0007] This solution, although advantageously simple thanks to the use of a single actuator member, has anyway a drawback in that, when said moving shutting member is being switched over to said first and said second positions, both the filling aperture and the dispensing aperture are temporarily open at the same time, actually, with the result that an uncontrolled amount of liquid is able to flow out from the dispenser through said two apertures arranged in series. This can alter to a substantial extent the actual dose of additive being dispensed each time, especially in the case that the shutting member is such as to switch over in a relatively slow manner.

[0008] It therefore is a main purpose of the present invention to provide a multi-dose dispenser of liquid additives for washing machines, which has a particularly simple and reliable structure and is at the same time capable of ensuring a particularly accurate volumetric metering of said additives without any need for a system of the afore mentioned "decanting" kind to be implemented.

[0009] A further purpose of the present invention is to provide a multi-dose dispenser of liquid additives of the above cited kind, which is capable of operating correctly and in an accurate manner without any electrically energized actuating means being actually required to ensure the operation of said dispenser.

[0010] According to the present invention, these and further aims are reached in a multi-dose dispenser of liquid additives for washing machines incorporating the characteristics as recited and defined in the appended claims.

[0011] Anyway, features and advantages of the present invention may be more readily understood from the description that is given below by way of nonlimiting example with reference to the accompanying drawings, in which:

• Figures 1 to 3 are schematic views of a first embodiment of the additive dispenser according to the present invention, in respective operating positions thereof; and
• Figures 4 to 6 are schematic views of a second embodiment of the additive dispenser according to the present invention, in respective operating positions thereof.

[0012] With reference to Figures 1 to 3 above, the additive dispenser can be contained within a housing 1 which accommodates at least a reservoir 2 adapted to be filled, via an appropriate upper aperture 3, with a substantial multi-dose amount of liquid additive, such as for instance a rinsing aid for dishwashing machines.

[0013] The bottom of the reservoir 2 is capable of fluidly communicating, via a filling aperture 4, with a volumetric metering chamber 5 situated therebelow, which in turn comprises, in the bottom thereof, an aperture 6 for dispensing such an additive. The latter can then be delivered into the washing vessel of the dishwashing machine via an aperture 7 provided in the bottom of the housing 1.

[0014] The filling aperture 4 and the dispensing aperture 6 are associated to respective shutter valves 8 and 9, respectively, which are distinct and capable of being actuated in a differentiated manner, as this shall be described in a more detailed manner further on.

[0015] The valve 8 is connected to a return spring 10 of the cap or similar type, or the like, which normally keeps it at a distance from the aperture 4, which is therefore open in the resting position thereof shown in Figure 1.

[0016] The valve 9 is in turn associated to a thrust spring 11, or the like, which normally keeps it in a position in which it closes the aperture 6.

[0017] The valves 8, 9 are substantially juxtaposed, i.e. provided in a substantial side-by-side arrangement, and are associated to an actuator 12, which may be of an electromagnetic kind or - preferably - of a thermally actuated kind.

[0018] The actuator 12 comprises a moving member 13 adapted to act on the valves 8, 9 via a lever 15 that is provided with respective pushing means 14, 16. In the resting position illustrated in Figure 1, a return spring 17 keeps said pushing means 14, 16 of the lever 15 in a condition in which they are substantially disengaged from the valves 8, 9.

[0019] As a result, in the resting position illustrated in Figure 1, the liquid stored in the reservoir 1 is able to flow by gravity into the metering chamber 5, thereby filling up the inner volume thereof.

[0020] When the actuator 12 is then operated, the moving member 13 thereof moves to act on the lever 15, by overcoming the force of the return spring 17, to bring the pushing means 14, 16 towards the respective valves 4, 6 until the dispenser, as ensured by an appropriate sizing of the component parts thereof, is brought into the transient condition illustrated in Figure 2. In this condition, the pushing means 14 brings the valve 8 into closing the aperture 4, by overcoming the force of the return spring 10, whereas the valve 9 keeps being closed. In this manner, the occurrence of a transient condition in which both apertures 4 and 6 are opened at the same time, under a resulting uncontrolled leakage of liquid from the reservoir 2 via the chamber 5, is effectively avoided.

[0021] It is just in the subsequent portion of the displacement travel of the lever 15 (Figure 3) that the pushing means 15 comes to engage the valve 9 to open the aperture 6, by overcoming the force of the respective return spring 11. At this point, the volumetrically metered amount of liquid that had previously filled up the chamber 5 flows out of said chamber by gravity via the dispensing aperture 6.

[0022] In order to facilitate such a dispensing, said metering chamber 5 may be provided with a vent pipe 18.

[0023] When the actuator 12 is deactivated, in a per se known manner, the return spring 17 causes the valve 9 to move back into the position in which it closes the dispensing aperture 6 (Figure 2) and the return spring 10 then causes the valve 8 to move back into its resting position in which it disengages from the aperture 4 (Figure 1). It is just and solely at this point that the liquid stored in the reservoir 2 is able to flow and fill by gravity the metering chamber 5, thereby preventing it from flowing out through the aperture 6 as the valves 8, 9 are changing over.

[0024] In conclusion, such a differentiated actuation of the valves 8, 9 in the above described manner is effective in avoiding any undesired delivery of additive during the changing-over transients to open/close the apertures 4 and 6. This is particularly important in the preferred case in which the actuator 12 is of the thermally operated kind, which has on the one hand the advantage of not requiring any power-supply connection, but, on the other hand, is only capable of ensuring relatively slow changing-over operations.

[0025] It shall be appreciated that the above described liquid-additive dispenser may be the subject of a number of modifications without departing from the scope of the present invention.

[0026] For instance, according to the embodiment illustrated in Figures 4 to 6, the volumetric metering chamber 5 may be provided in correspondence of a piston 19 that is capable of sliding tightly with respect to a cylinder 20 arranged below the reservoir 2. In particular, the metering chamber 5 is delimited within the cylinder 20 by two head-walls 21, 22 of the piston, each one of which preferably cooperates with the side surface of the cylinder 20 through respective sealing rings 23, 24 or the like.

[0027] In the embodiment illustrated in Figures 4 to 6, the filling aperture 4 and the dispensing aperture 6 are provided in correspondence of the side surface of the cylinder 20 and the axial distance from each other is equal to or greater than the axial distance of the two head-walls 21 and 22 of the piston from each other. The piston itself is normally kept in its raised resting position shown in Figure 4, in which the metering chamber 5 is in communication with the multi-dose reservoir 2 via the aperture 4 and, therefore, is able to fill up with liquid additive, thanks also to the provision of the vent tube 18.

[0028] The piston 19 is capable of being operated by the actuator 12 via a connection 25 provided with a return spring 17. When the actuator 12 is operated, the moving member 13 thereof acts on said connection 25 so as to cause the piston 19 to slide towards a lower end-of-stroke, until the dispenser is brought into the transient condition illustrated in Figure 5. In this condition, the walls 21 and 22 of the piston are comprised between the apertures 4 and 6, which are therefore unable to communicate with the metering chamber 5, with respect to which they are in fact closed. Also in the case of the embodiment of the invention, therefore, the occurrence of a transient condition in which both apertures 4 and 6 are opened at the same time, under a resulting uncontrolled leakage of liquid from the reservoir 2 via the chamber 5, is effectively avoided.

[0029] It is just in the subsequent portion of the displacement stroke of the piston 19 (Figure 6) that the aperture 6 is axially passed beyond and cleared by the wall 22, thereby establishing a communication with the metering chamber 5. At this point, the volumetrically metered amount of liquid that had previously filled up the chamber 5 flows out of said chamber by gravity via the dispensing aperture 6 itself.

[0030] When the actuator 12 is deactivated, the piston 19 slides back into its resting position shown in Figure 4 by passing through the transient position shown in Figure 5.

[0031] Therefore, the apertures 4 and 6 are in the first place both in their closed condition (Figure 5) and the aperture 4 is then cleared axially by the wall 21 of the piston 19 passing therebeyond, so that it is now able to communicate with the metering chamber 5. It is just and solely at this point that the liquid stored in the reservoir 2 is able to flow by gravity to fill up the metering chamber 5, thereby preventing it from flowing out through the aperture 6 as the walls 21 and 22 of the piston 19 are moving during a change-over stroke thereof. In this case, it can be appreciated that said piston walls are substantially equivalent to the valve members 8, 9 that have been described previously with reference to Figures 1 to 3.

[0032] Also in the case of the embodiment illustrated in Figures 4 to 6, therefore, in which the walls 21 and 22 of the piston are operated at the same time in the afore described manner, this proves effective in avoiding any undesired delivery of additive during the changing-over transients to open/close the apertures 4 and 6.

[0033] It will of course be readily appreciated that some of the features of the two afore described embodiments of the present invention may be appropriately combined in a variety of manners, according to the needs.

Claims

1. Multi-dose dispenser of liquid additive for washing machines, comprising at least a multi-dose reservoir for storing said liquid additive adapted to communicate via a first normally open filling aperture with a volumetric metering chamber which in turn comprises at least a normally closed dispensing aperture, shutter means being controlled by actuator means to alternately open and close said apertures in such a manner as to deliver through said second aperture pre-determined amounts of additive that are let into the metering chamber through said first aperture, characterized in that said shutter means (8, 9; 21, 22) are adapted to only open the second aperture (6) after they have closed the first aperture (4), and to open again the first aperture (4) only after they have closed again the second aperture (6).

2. Liquid-additive dispenser according to claim 1, characterized in that said actuator means comprise a thermally actuated member (12) adapted to change over said shutter means (8, 9; 21, 22) between respective positions for closing and opening said apertures (4, 6).

3. Liquid-additive dispenser according to claim 1, characterized in that said shutter means comprise a distinct valve member (8, 9) for each one of said apertures (4, 6), said valve members being adapted to be operated in a differentiated manner by said actuator means (12) via transmission means (14-16).

4. Liquid-additive dispenser according to claim 3, characterized in that said transmission means comprise a lever (15) connected to said actuator means (12) and said valve members (8, 9), the latter being provided in a substantially side-by-side arrangement.

5. Liquid-additive dispenser according to claim 1, characterized in that said volumetric metering chamber (5) is provided in correspondence of a piston (19) adapted to slide tightly, as controlled by said actuator means (12), with respect to a cylinder (20) arranged below said reservoir (2), the metering chamber (5) being delimited, within the cylinder (20), by two walls (21, 22) of the same piston.

6. Liquid-additive dispenser according to claim 5, characterized in that said apertures (4, 6) are provided in correspondence of the side surface of the cylinder (20) and the axial distance from each other is equal to or greater than the axial distance of said walls (21, 22) of the piston (19) from each other.

Drawing