EP0486790B1

EP0486790B1 - Dish-washing machine with multidose dispenser of powder detergent

Info

Publication number: EP0486790B1
Application number: EP91116393A
Authority: EP
Inventors: Gianni Sandrin
Original assignee: RO-SA MICROMECCANICA SNC; RO Micromeccanica SNC SA
Current assignee: RO-SA MICROMECCANICA SNC; RO Micromeccanica SNC SA
Priority date: 1990-10-03
Filing date: 1991-09-26
Publication date: 1994-07-27
Anticipated expiration: 2011-09-26
Also published as: DE69103127D1; IT1242800B; ES2061142T3; IT9045758A0; EP0486790A1; DE69103127T2; IT9045758A1

Description

The current trend toward the use of household electrical apparatus and appliances featuring an ever-increasing number of automatisms, recently became so ample as to include the elimination of the preliminary set-up operations and, in particular, the elimination of those operations required to fill the dispenser of the concerned appliance with detergents and other substances every time the machine has to be used, by replacing them with automatically controlled operations actuated by special devices.
At present, the dishwashing machines are prearranged to feed the washing tank with powder or liquid detergents by means of a conventional detergent dispenser connected with said tank and subdivided into various separated and independent compartments each one of them containing the respective detergent.
In this manner, the different compartments of the dispenser are filled with predetermined doses of powder or liquid detergents which are then directly or indirectly removed by the water of the washing tank. The dispensing devices presently employed in case of powder detergents are of the single-dose type so that the user, at every washing cycle, must fill a special tray with detergent which then, through a signal command sent by an appropriate control device (programmer) is introduced into the washing tank to be dissolved in the washing water.
These devices are rather reliable and simple in their use, but they compel the user to perform, at every washing cycle, a new filling operation.
Further, the filling operation requires a great attention since the occurrences in which the amount of detergent is incorrect, and often excessive, are quite frequent, and obviously these erroneous amounts of detergent determine a loss of money as well as a higher pollution of the drained water.
Furthermore, when using a dishwashing machine, it is necessary, as a rule, to open its door completely and fill the dispensers located at the inner side of the door itself so that the user is compelled to bend almost down to the floor with a considerable discomfort and also, especially in the case of aged persons, a great effort.
Washing machines equipped with means suitable to contain large amounts of detergents, particularly liquid detergents, are well-known in the prior art.
These prior art detergent containing means consist essentially in a plurality of high capacity rigid type containers, appropriate to hold liquid substances, connected with the washing tank through their respective conduits, the latter being provided with volumetric pumps.
Although these rigid type containers satisfactory fed with liquid detergent or liquid detergent components the washing tank of the machine, the room they take up is not however available, as a rule, inside the washing machine but must be found outside of it.
In fact, examples of washing machines and dishwashing machines in which the reservoirs of liquid substances are arranged outside the machine, preferably assembled together into an appropriate container placed side by side with the machine, are well-known in the prior art.
The height and depth of said prior art container correspond, as a rule, to those of the machine itself so to comply, at least in part, with the existing dimensional standards.
However, this type of embodiment has two disadvantages: first of all, it takes up an additional room which, as it is well-known, especially in the modern houses is limited, and secondly, it demands the use of detergents in liquid form which, at the present time, are still less effective and more polluting than the detergents in powder form.
Further, each one of the different washing programmes prearranged by the manufacturer of dishwashing machines may normally call for different amounts of detergents; such "to-size" dosage has already been divulged in DE - 3833961 and in DE - 3903636; especially the latter document illustrates a detergent dispenser mounted inside the door of a dishwashing machine, and which is able to contain a plurality of dosages which are singolarly poured into the washing tub according to the washing phase.
However these documents do refer to detergent dispensers designed to operate with liquid detergents only, what is keeping the cited drawbacks pertinent to such a type of substances; therefore no solution is yet available relevant to dispensers of detergent in powder form, able to contain a quantity of powder sufficient for a plurality of washing cycles and to supply a dosed quantity of it for each washing cycle and according to the washing phase.
Therefore, it is desirable and it is an object of the present invention to provide a dishwashing machine equipped with a powder detergent reservoir which makes it possible both to accomplish several consecutive washing cycles without the need of replenishing every time the required amount of detergent and delivery, into the washing tank, in due times during the washing cycle, the single doses of detergent, being the amount of the latter differentiated in accordance with the type of the preselected washing programme.
This object is attained by means of a simple in its design, easy-to-use, reliable and economic integrated device to be installed in a removable manner inside a dishwashing machine, being said integrated device so made as to incorporate the functions of both a multidose reservoir and a dispenser of detergent in powder form, and being said integrated device obtainable with the customary processing techniques.
The invention will be best understood from the following description given by way of non-limiting example when read in connection with the accompanying drawings, in which:

Fig. 1 shows schematically a detergent reservoir-dispenser device according to the invention.
Fig. 2 and 3 show schematically two variations of a detail of said device.
Fig. 4 and 5 show schematically two variations of a second detail of said device.
Fig. 6 shows schematically a handle for engaging and disengaging said device.
Fig. 7 shows schematically two views of a further detail.
Fig. 8 illustrates the method of insertion and extraction of said device at the inner side of the door.
Fig. 9 shows the device in its inserted and engaged position.
Fig. 10 illustrates a typical method for filling the device with detergent in powder form.

The automatic powder detergent dispenser is composed of a shell 1 screwed and gasketed into and against an opening obtained on the inner wall of the door 2 of the dishwashing machine and of a reservoir-dispenser 3 inserted into said shell 1 in such a way as to allow the user to slide it out for an easy replenishment of detergent as it will be explained later on.
Said reservoir-dispenser, removable by the user, is inserted and fixed into said shell 1 by means of a handle which has also the function of locking the reservoir-dispenser in place.
Said reservoir-dispenser, essentially shaped like an "L" as illustrated in Fig. 1, can be inserted into said shell 1 installed on the door inner wall, in such a way and position that its upper part, when the door is closed, cannot be lapped by the water, as illustrated in Fig. 8 and 9.
This embodiment, which has the advantage of limiting the area of direct exposure to the spouts of water, reduces the possibility of water seepages and maintains lower the average temperature inside the detergent dispenser thus allowing a better detergent preservation.
The lower part of the reservoir-dispenser, corresponding to the base of said "L", houses the detergent dispenser and, obviously, said part of the reservoir-dispenser, when the door is closed, is disposed in a downward direction since the detergent is fed by gravity into the washing tank.
The removable reservoir, which consists of a box-like hollow body 4, can be filled with an amount of detergent sufficient for numerous washing cycles.
The lower part of said removable reservoir is connected with a dispenser 5 provided with a feedbox 6 which receives the detergent from the reservoir and conveys then it to a predetermined-volume container or metering chamber 7.
A first separating element 8, placed between the reservoir feedbox 6 and said metering chamber 7, can slide transversally and hence preclude or enable the passage of the detergent in powder form into the metering chamber 7.
The end of said metering chamber 7, positioned toward the washing tank is hermetically closed by means of a hinged movable lid 9 which, when swung closed, lies flat on a seat provided with a well-dimensioned water-tight gasket 10.
The purpose of said gasket 10 is to preclude that spouts of water leak into the side compartments 7a of the chamber 7 thus clogging said compartments and hence impairing their function.
Said compartments 7a, as shown in Fig. 1, collect the detergent occasionally strained out from the separating element 8 and discharge then said detergent into the washing tank when the movable lid 9 swings open.
The coupling between the box-like hollow body 4 and the dispenser 5 can be assured by a spring-lock restrained joint 18 or by an equivalent means, capable to assure however a perfect seal.
Said first separating element 8 consists of a movable very flat perforated lamina 11, preferably a thin chrome-nickel steel diaphragm, superimposed and sliding over the aperture 12 of the metering chamber 7, said aperture 12 and that of said movable lamina being identical and coincident so that for opening the passage between the feedbox 6 and the metering chamber 7 it is required that the movable lamina 11 slides over said aperture 12.
A distinctive feature of the device is the special configuration of the contact zone between the sliding diaphragm and the rims of the apertures of both the feedbox 6 and metering chamber 7.
In fact, the hermetic peripheral closing contact of said movable perforated lamina in correspondence with the rims of the apertures of both the feedbox and metering chamber is assured by a perimetrical knife-edge contact 13 which closes perpendicularly and elastically between the inlet lip of the metering chamber 7 and a lip, elastically fixed at the outlet of the feedbox 6 so as to assure between them an uninterrupted and uniform contact suited to preclude the passage of detergent.
The elastic pressure necessary for granting the required seal and elasticity to said contact parts 13 is, preferably, assured by a plurality of springs 14 acting on said parts.
Fig. 2 and 3 show respectively an enlarged view of said contact zone and a variation to spring 14, consisting of an elastomer element 14, compressible between said movable parts 13 and said feedbox 6.
To drive the movement of the movable lamina 11 and movable lid 9, it would be simple and easy to have recourse to the available techniques usually employed for the actuation of mechanical elements which are well-known to anyone skilled in art.
A preferred embodiment of a driving mechanism is described hereinafter:
Said elements 11 and 12 are actuated, preferably by means of a rotary motion, applied to them through corresponding shafts, cams, pins or other equivalent means 15 on which they are keyed.
Said elements, comprised in said dispenser, are out-timed in their movements so that when the detergent has to be released into the washing tank, said first separating element, normally open, closes before said movable lid opens and, conversely, after said detergent has been released, said movable lid closes before said first separating element opens.
Said means 15, which transmit the motion to the movable perforated lamina 11 and to the movable lid 9, are driven by an actuator 16, mounted outside the shell on the inner side of the door, and they are acting on said means 15 through one or more pin-like elements 17, the latter being part of said actuator 16, as shown in Fig. 1 and 5.
It is evident that the device will operate properly when, with the actuator in a stop motion condition, said element 17 will be set inwardly inside the shell and will engage with said means 15 through appropriate openings obtained on the wall of the shell 1.
The operation of this device is the following:
To fill the reservoir with detergent, the user disengages and slides, in a combined outward-upward direction, out of the housing shell 1 located on the inner wall of the door, and away from the actuator 16, the complete reservoir-dispenser unit.
In this way, the device can be removed and placed onto a table to be filled with detergent in powder form.
To replenish the detergent, it is sufficient to disengage the locking and sealing means 18, disjoin the reservoir from the dispenser 5 and fill then the reservoir with detergent. After this filling operation, the reservoir will be joined again with the dispenser and the device is then re-inserted into its housing shell inside the dishwashing machine.
When detergent has to be supplied to the dishwashing machine, the actuator 16, being powered, makes the pin 17 come out its seat thus actuating the means 15 which slide closed the separating lamina 8 and swing open the lid 9.
The operation sequence takes place as follows:

Sliding closed of diaphragm 8 and hence closing of the passage of detergent in powder form into the metering chamber 7;
Swinging open of lid 9 and hence falling of the detergent into the washing tank;
Swinging closed of lid 9;
Sliding open, in a rest position, of diaphragm 8 and hence refilling of the detergent dose thus allowing the replenishment of detergent in the metering chamber 7.

During the above described operation sequence, the washing pump is kept in a stop motion condition in order to avoid that spouts of water can enter inside the device. The detergent is supplied to the washing tank every time an appropriate electrical actuator is energized by the programmer of the dishwashing machine.
Said actuator is acting on the movable lamina as well as on the movable lid in accordance with the above described operation sequence, i. e. first, the detergent already in the metering chamber falls into the washing tank, then, the movable lid swings closed and, finally, the movable lamina slides open so to allow the replenishment of the required amount of detergent into the metering chamber.
An useful improvement of this device is obtained if, as shown in the drawings, said movable lid 9 is arranged remarkably slanting with respect to the longitudinal axis of the metering chamber 7. In fact, with this arrangement it is possible to swing open the movable lid by means of a minimum rotation of the shaft 15 on which the movable lid is keyed thus simplifying the driving mechanism.
As a matter of fact, if said lid 9 were arranged perpendicularly with respect to the longitudinal axis of the metering chamber 7, in order to swing open said movable lid it would be necessary to make it rotate a complete right angle, which is a more complex operation than that performable by the use of the above described improvement.
It is evident that it is possible to adjust the amount of detergent to be supplied into the washing tank at every washing cycle, simply performing said operation so many times as required by means of proper control commands sent to the actuator by the programmer.
A further improvement of this device is obtained by providing the dispenser with a special engaging and locking handle 22.
Said handle is rotatably mounted on that part of the dispenser facing the washing tank, the rotary motion of said handle being controlled by a counteracting spring, not shown in the drawings, said counteracting spring, when in its rest position, making said handle rest against and into an undercut provided on the dispenser housing shell, as shown in Fig. 8 and 9.
Also, said handle can advantageously lock in place the dispenser, once the latter is inserted into its housing shell 1, by adopting the following arrangement:
A pin-like or plate-like shaped tongue 25 is fixed on the inner wall of the door in correspondence with a protruding element 23 of the base 24 of said handle.
A recess 26, coincident with said tongue 25, is provided in said protruding element 23 so that, when the handle is being rotated outwardly forcing the counteracting spring action, said recess 26 disengages from said tongue 25 and when the handle is released, said recess engages with said tongue 25.
The operation of this handle will appear clear from the following description:
To set in place the device, the user first insert the dispenser completely into the housing shell 1 utilizing said handle 22. The handle, being now released, due to the action of the counteracting spring is moved to rest against the dispenser housing shell surface while the tongue 25 is being inserted into the recess 26 thus locking in place the dispenser.
Conversely, to slide the dispenser out its housing shell, the user will proceed by following the reverse operation sequence which is not here described for the sake of brevity.
However, to obtain a perfect operation of the device it is necessary to adopt a further improvement. In fact, due to both the progressive emptying of the reservoir 4 and the effect of the rapid cooling of the dispenser wall facing the washing tank during the pre-washing cycles as well as to the cold water circulation, a vacuum may occur inside the reservoir 4 which could impair the regular and accurate filling of the metering chamber 7.
To counter an inconvenience of this type, a further improvement of the device should be adopted.
This improvement will consist in a compensating valve installed at the top 27 of the reservoir, for instance as shown in the drawings.
The use of a conventional valve consisting of a movable stem applied and passing through said reservoir top and beating against the corresponding upper wall of the housing shell 1, said valve closing and opening suitable holes made on said top in the nearest proximity of said stem, creates however the inconvenience that when the reservoir has to be filled with detergent, said reservoir, as a rule, is placed to rest onto a table so that said reservoir actuates the opening of said valve with the consequence that the valve gets immediately clogged with detergent so losing its efficiency and damaging the table surface as well.
To avoid said inconveniences, it is suggested to provide the reservoir with a special, free from moving parts flat valve, consisting of a plug 31, made of a material permeable to the air but not to the detergent, as for instance a sintered material, covering and closing permanently the inner side of the reservoir vent hole 30 so that the reservoir outer surface surrounding said vent hole 30 remains flat.
The corresponding zone of the surface of the shell 1 is slightly hollowed outwardly and in this shallow recessing it is obtained a second hole 32, coaxial with the first one and provided with an extending outwardly regular cylindrical crown 35 inside which a finned pin 33, provided with a plurality of longitudinal channels 34 arranged between a fin and the other, is axially inserted.
The upper end of said pin 33 is provided with a horizontally disposed closing valve 37 which can cover the rim of crown 35 and hence close said channels 34. Inside the shell, the lower end of said pin is provided with a stop element 36 against which the reservoir is pressing during the insertion of the dispenser.
The geometry and dimensions of the valve assembly are such that when the reservoir is inserted inside its housing shell, the former, by beating with its upper wall against the pin 37, pushes the latter up thus lifting the valve and hence freeing the channels 34.
In short, when the device is inserted into its housing shell, an air passage is automatically opened between the exterior and the interior of the reservoir via said channels 34, shallow recessing on the shell, vent hole 30 and plug 31, the latter allowing the inflow of air without being however clogged due to its characteristics.
When the reservoir is being filled with detergent, the plug 31, due to the characteristics of the material with which it is made from, cannot be clogged and further, the surface of the reservoir resting onto the table during the detergent replenishment is regular and flat.
To avoid that humidity and heat coming from the washing tank could possibly enter inside the reservoir 4 by passing through the interface 39 existing between said reservoir and the inner wall of the housing shell 1 and then through the vent hole 30, it is advisable to seal said passage by means of an appropriate, resilient lip type gasket 38, tapered toward the shell, as shown on the drawing by dotted line 40, and enclosing the stop element 36, so that when the dispenser is inserted into the shell, the bottom wall 37 of the former, by pushing against the stop element 36, causes the contact and hence the closing of said gasket 38 against the said shallow recessing thus inhibiting the passage between the interface 39 and the inside of the reservoir.

Claims

A dishwashing machine, particularly a domestic dishwashing machine, comprising a washing tank, a door (2) to load and close said washing tank, an housing shell (1) obtained on the inner wall of said door, and a reservoir-dispenser assembly (3) containing detergent in powder form, said reservoir-dispenser (3) consisting of a detergent reservoir (4) and a dispenser (5), the latter, detachable from the former, being capable of releasing a single dose of detergent at a time and containing an amount of detergent sufficient for a plurality of washing cycles, said reservoir-dispenser assembly (3) being removably inserted into said housing shell (1) fixed behind the inner wall of said door (2), and being positioned in such a way, that when said door (2) is closed, said reservoir-dispenser assembly (3) is disposed with the reservoir (4) facing upward so that the detergent releasing mouth of the dispenser (5) is facing downward, the dose of detergent required during said washing cycles, being drawn from said reservoir (4) through said dispenser (5), characterized in that the bottom of said reservoir (4) communicates with a metering chamber (7) of said dispenser (5) through a feedbox (6) and a movable separating element (8) introducible between said feedbox and said metering chamber.
A dishwashing machine according to claim 1, characterized in that said metering chamber (7) leads directly to said washing tank through a movable lid (9) located on the bottom of said metering chamber, said movable lid being normally closed.
A dishwashing machine according to claim 2, characterized in that said movable lid (9) when in its normally closed position and with the door closed, is remarkably slanting with respect to the longitudinal axis of the metering chamber (7).
A dishwashing machine according to claims 1, 2 or 3, characterized in that said first separating element (8), when the detergent has to be released from the metering chamber (7) to the washing tank, closes before said movable lid (9) opens and conversely, after the detergent is released, said movable lid (9) closes before said first separating element opens.
A dishwashing machine according to claim 4, characterized in that said first separating element (8) and said movable lid (9) rotate on their respective shafts or pins (15), said shafts or pins being driven by one or more actuating elements (16, 17) located inside said door.
A dishwashing machine according to any one of claims from 1 to 5, characterized in that said first separating element (8) consists of a movable, preferably very thin perforated lamina (11), superimposed and capable of sliding across the aperture (12) of the metering chamber (7) and located at the bottom of the feedbox so as to close the latter, said aperture and that of said movable lamina being identical so that for opening the first separating element it is required that said movable perforated lamina (11) slides across said aperture (12).
A dishwashing machine according to claim 6, characterized in that the hermetic peripheral closing contact of said movable perforated lamina is assured by a movable wall (13) closing elastically against the nonperforated surface of said movable lamina (11).
A dishwashing machine according to any one of the preceding claims, characterized in that said movable lid (9), closing said metering chamber, closes hermetically by means of appropriate gaskets (10) also the downward directed side compartments (7a) and encloses said movable perforated lamina (11) and said movable wall (13).
A dishwashing machine according to any one of the preceding claims, characterized in that the reservoir-dispenser assembly (3) is provided with a handle (22) which can be opened by swinging it toward the washing tank and can be closed by letting it swing automatically back to its closed position, said handle being provided with a recess (26) suitable to get engaged, when said handle has to be closed, with a tongue (25) fixed on the inner wall of the door and to get disengaged from said tongue when said handle has to be opened.
A dishwashing machine according to any one of the preceding claims, characterized in that the upper part of the reservoir (4) includes an air inflow valve, said valve being automatically opened when the reservoir-dispenser assembly (3) is inserted into the housing shell (1).
A dishwashing machine according to claim 10, characterized in that said valve consists, inside the reservoir (4), of a vent hole (30) obtained on the upper wall of said reservoir and of a plug (31) which covers and closes from the inside said vent hole (30), said plug being made of a material permeable to the air and not to the detergent, as for instance a sintered material, and of an outward shallow recessing obtained on the housing shell (1) in front of said vent hole (30), said shallow recessing being provided with a second hole (32) substantially coaxial with the first one and provided with an extending outwardly regular cylindrical crown (35) inside which a finned pin (33), provided with a plurality of longitudinal channels (34) arranged between a fin (33a) and the other, is axially inserted, the upper end of said pin (33) being provided with a horizontally disposed closing valve (37) which can cover the rim of the crown (35) and hence close said channels (34), and the valve end inside the housing shell being provided with a stop element (36) against which the reservoir is pressing during the insertion of the dispenser.
A dishwashing machine according to claim 11, characterized in that a gasket (38) is interposed between the external perimeter of said vent hole (30) and the inner part of said shallow recessing of the housing shell (1), said gasket being capable of closing the passage from the interface (39) of the housing shell (1) to the vent hole (30) and hence to the inside of the reservoir (4).