EP0554676A1

EP0554676A1 - Improvement in the detergent dispenser of a dishwashing machine

Info

Publication number: EP0554676A1
Application number: EP93100429A
Authority: EP
Inventors: Gianni Sandrin
Original assignee: RO-SA MICROMECCANICA Sas
Current assignee: RO-SA MICROMECCANICA Sas
Priority date: 1992-02-05
Filing date: 1993-01-14
Publication date: 1993-08-11
Also published as: ITPN920003V0; ITPN920003U1; IT229025Y1

Abstract

Dishwashing machine, particularly of the household type, comprising a dispenser of detergent in powder form consisiting of a metering chamber (7), said chamber being capable of being closed and opened at its bottom seat facing the washing tank by means of a pivoting lid (9), in which, in correspondence of the inner surface of said lid, a preferably flexible element (15) is provided, said element (5) being spaced a slight distance from said inner surface.

The lower wall (8) of the metering chamber terminates at its lower end with an oblique profile which is delimited at the top by a relief (18) formed as a stepped portion in a closed-loop configuration along said inner wall. With the lid in its closed position, said flexible element (15) enters the lower portion of the metering chamber with its outer periphery cutting neatly and wipingly into it, until it ultimately rests with its outer edge exactly against the afore cited relief (18).

In view of enhancing the closing movement of the lid, a permanent magnet and a corresponding ferromagnetic element may be provided on the matching surfaces of the lid and the metering chamber (7).

Description

The present invention relates to an improvement in the detergent dispensers used in dishwashing machines, in particular of the household type.
Dishwashing machines are already being used, which are arranged to feed the washing tank with powder or liquid detergents by means of a conventional detergent dispenser connected with said washing tank and divided into various separate and independent compartments, each one of said compartments being provided to contain a respective detergent. In this way, the different compartments of the dispenser are filled with predetermined doses of powder or liquid detergents before starting the washing process, and said doses are then directly or indirectly removed from the compartments by the water as it flows to the washing tank for performing a phase of the washing process.
The dispensing devices presently employed in the case of powder detergents can be of both the single-dose type, wherein the user must before every washing cycle fill a special tray with detergent which then, through a command signal issued by an appropriate control device (programmer), is introduced into the washing tank so as to be dissolved in the washing water, and of the multi-dose type, as this is for instance disclosed in the Italian patent application no. 45758/A/90 filed by the same applicant.
In fact, the afore cited patent application discloses a dishwashing machine which is equipped with a powder detergent reservoir which makes it possible both to operate during several consecutive washing cycles without it being necessary to each time replenish said reservoir with the required amount of detergent, and to deliver single doses of detergent into the washing tank at appropriate moments during each washing cycle, the amount of the doses being capable of being varied in accordance with the preselected washing programme.
All these functions are ensured through the use of an integrated device doubling functionally as a multi-dose detergent reservoir and a powder detergent dispenser, to be installed inside a dishwashing machine.
This integrated device includes a shell inserted into an opening and screwed and gasketed to the inner wall of the door of the dishwashing machine, and a reservoir-dispenser arrangement capable of being removably inserted into said shell in such a way as to allow the user to slide it out for an easy and convenient replenishment of detergent.
The lower portion of the arrangement accomodates the dispenser and is naturally extending in a downward direction when the door of the dishwashing machine is closed, since the detergent is fed by gravity into the washing tank.
The slide-out reservoir portion of the reservoir-dispenser arrangement consists of a box-like hollow body accomodating the detergent in powder form, is arranged to be connected on its lower side with the detergent dispenser portion of the arrangement, and can be filled with an amount of detergent sufficient for numerous washing cycles.
Said dispenser device includes a hopper-like feedbox which receives the detergent from the reservoir and conveys it to a predetermined-volume container forming a metering chamber. A first separating element, which can slide transversely and, therefore, preclude or enable the passage of the detergent in powder form into said metering chamber, is placed between the feedbox of the reservoir and said metering chamber.
The metering chamber is hermetically sealed, in correspondence of its base facing the washing tank , by means of a movably hinged lid which, when swung closed, not only seals that chamber, but also lies flat on a seat provided with a well-dimensioned water-tight sealing gasket.
The purpose of this gasket is to prevent water from leaking into the compartments at the sides of the metering chamber and thus clogging said compartments and impairing their function.
The use of such a device is simple and reliable, but it can nevertheless occur that, notwithstanding the provision of the afore mentioned water-tight sealing gasket in correspondence of the lower edges of the seat defining the metering chamber, when the movably hinged lid is opened a film of humidity may in fact form on the inside surfaces of the chamber and along the lower edges thereof, on which said movably hinged lid rests flat.
It may therefore occur that, upon prolonged use, ie. successive openings of the movably hinged lid, the powdered detergent contained therein may come into contact with said lower edges of the seat of the chamber, thereby forming dense clots of moistened detergent powder.
Because this effect tends to increase spontaneously and progressively, a halo of moist detergent may thus form at the lower end of the metering chamber. In this case the following problems arise. On the one hand, the movably hinged lid no longer covers and seals the metering chamber sufficiently, so that there is an undesirable outflow of detergent into the washing tank before the time intended, resulting in a loss of efficiency of the washing process. On the other hand, this halo of mostened detergent clot tends to prevent the lid from moving toward the seat of the chamber, thus obstructing its complete closing and the correct functioning of the control mechanism.
Therefore, it is desirable, and it is in fact an object of the present invention, to provide a detergent dispenser which is free of the afore cited drawbacks, is simple, economic and reliable in its use and construction, and makes use of manufacturing techniques normally employed in the sector.
This object is attained by means of an improved lid, which is provided, on its internal surface, with such an element as to prevent clots of moistened detergent powder from possibly forming along the lower edge of the seat of the metering chamber, as well as a magnetic element for assisting said lid when closing.
The invention will be best under stood from the following description of a non-limiting example made in connection with the accompanying drawings, in which:

Figure 1 is a schematic diagram of the powder detergent metering chamber, with related sealing lid, in accordance with the present invention.
Figure 2 is an enlarged view of the cross-section of the sealing lid shown in Figure 1.
Figures 3, 4 and 5 are enlarged views of various details of the metering chamber shown in Fig. 1.

Referring now to the above listed Figures, following items can be noticed: the metering chamber 7, the lower wall 8 delimiting said metering chamber, the sealing lid 9, and the centre of rotation 19 of said lid.
In correspondence of the internal surface of the lid 9, a thin, preferably flexible element 15, such as for instance a thin metal lamina, is arranged, whereas this lamina is spaced a slight distance from said internal surface by means of a plurality of support pillars 16 and the tips of bracing elements 17.
The outer periphery of said element 15 has a shape which is essentially complementary to, but smaller than that of the lid 9 by such a measure as will be explained in detail later on.
Referring now to the Figures 3, 4 and 5, it can be noticed that the lower inner wall of the metering chamber has an oblique-angle profile 8 facing downwards, said profile being closed by a relief 18 provided as a stepped portion against said inner surface, arranged on a substantially transverse plane with respect to said inner surface in a closed-loop configuration.
The afore mentioned elements are such in their dimensions and shape that, when the lid 9 is pivoted about its centre of rotation 19 in its normal closed position, said element 15 enters the lower portion of the metering chamber with its outer periphery cutting neatly and wipingly into it, until it ultimately rests with its outer edge exactly against the afore cited stepped portion 18 provided on the inner edge of the wall 8 of said chamber 7.
Thus, when the lid is in its closed position, the metering chamber 7 is hermetically sealed by a double closure. As a matter of fact, a first closure is ensured by the lid 9, which in a preferred way is of elastomeric material, resting against the lower edge of the wall 8 defining said metering chamber, whereas a second closure is provided by said element 15 resting hermetically against the afore cited stepped portion 18.
It has actually been found that, with the above illustrated configuration, the double closure achieved in such a way between the lower portion of the metering chamber 7 and the lid, including said element 15, is effective in preventing clots of moist detergent powder from forming and building up on said lower edge of the chamber. As a matter of fact, the special sharp profile of said flexible element 15, in conjunction with the relief 18 provided with a matching profile along the lower inner edge of the metering chamber 7, is effective in ensuring that said clots of moist detergent are actually wiped off and removed each time that the lid is closed, since the progressive "insertion" of said element 15 prevents said clots from being held back and gradually building up therebetween.
Practically this means that the above described arrangement is effective in ensuring automatic cleaning of the matching surfaces each time that the lid is closed.
A further improvement of the arrangement according to this invention can be provided based on the fact that the higher is the pressure with which said surfaces are wedging in, the greater is the force with which the clots of moist detergent possibly adhering therebetween are removed.
To this purpose, it is therefore advantageous that the closing force of said surfaces against each other be increased, in particular during the final phase of the closing movement, since a greater closing force would quite obviously be of no practical effect during the initial approaching phase.
Therefore, in view of increasing said closing force during said final phase of the closing movement, a useful improvement resides in providing two or more permanent magnets 19 to be installed in correspondence of the matching point of said surfaces, preferably adjacent the lower edge of the metering chamber 7, as shown in Figure 1, as well as in providing corresponding ferromagnetic elements 20 on the inward side of the lid 9.
A greater force will of course be needed also to separate said two surfaces when the lid is expected to open under the control of the appropriate arrangement. However, this can be achieved through a number of solutions that certainly fall within the abilities of anyone skilled in the art.
For instance, the movement of the lid could be controlled by a mechanical system provided with cams having such a profile as to ensure that the initial phase of the separation movement occurs slowly, but at a torque which is high enough to bring about said separation effectively, whereas the subsequent movement is considerably faster since a much lower resistance is now offered by the magnet(s).
Il will be appreciated that the above described and illustrated embodiments are merely intended as non-limiting examples of the present invention, and that they may be the subject of any modifications considered to be appropriate, without departing from the scopes of the invention.

Claims

Dishwashing machine, in particular of the household type, comprising a washing tank, a loading door to close said washing tank, a dispenser of detergent in powder form consisting of a feedbox that receives the detergent from a reservoir and delivers it into a metering chamber (7), said chamber being arranged to being opened and closed at its lower end facing the washing tank by means of a movably hinged lid (9) pivoting about a corresponding centre of rotation (19), characterized in that:
- in correspondence of the inward facing surface of the lid (9) a preferably flexible element (15) is provided, which is spaced a slight distance from said inward facing surface by means of a plurality of support pillars (16) and the tips of bracing elements (17);

- said element (15) has an outer periphery which is substantially complementary to, but smaller than that of said lid (9);

- the lower wall (8) of the metering chamber terminates at its lower end with an oblique profile, said oblique profile being delimited at the top by a relief (18) formed as a stepped portion in a closed-loop configuration along said internal wall, arranged on a substantially oblique plane with respect thereto;

- the above cited elements (7, 8, 9, 15, 16, 17, 19) have such dimensions and shape that when the lid (9) is caused to pivot about its centre of rotation (19) to move in its closed position, said flexible element (15) enters the lower portion of the metering chamber with its outer periphery cutting neatly and wipingly into it, until it ultimately rests with its outer edge exactly against said relief (18) provided along the internal edge of the lower wall (8) of said metering chamber (7).
Dishwashing machine as claimed in claim 1, characterized in that a plurality of permanent magnets (19) is provided externally to and adjacent the lower edge (8) of the metering chamber (7), along with corresponding ferromagnetic elements (20) provided on the inner face of said lid (9) and arranged in front of said magnetic elements (19) when the lid (9) is in its closed position.
Dishwashing machine as claimed in any of the preceding claims, characterized in that said element (15) is a thin metal lamina.