WASHING AGENTS DISPENSER FOR A DOMESTIC WASHING MACHINE, NAMELY A DISHWASHER

Abstract: A dispenser of washing agents is described, for a household washing machine, in particular a dishwasher, said dispenser (10) comprising a tank (12) for containing a liquid washing agent to which a visual control device (17-18) is associated, of the level of said liquid washing agent, said control device comprising a passage (18), placed between said tank (12) and the external part of the body (11) of the dispenser (10), and an element in a substantially transparent material (17) inserted in said passage (18), a first portion (22) of said transparent element (17) being at least partially visible from the outside of said body (11) and a second portion (17B) of said transparent element (17) being inserted in said tank (12), where at the free end of said second portion (17B) a series of projections (20) is defined, being placed at different levels of height.

Description: WASHING AGENTS DISPENSER FOR A DOMESTIC WASHING MACHINE, NAMELY A DISHWASHER DESCRIPTION The present invention relates to a dispenser of washing agents for a household washing machine, in particular a dishwasher, of the type indicated in the preamble of annexed claim 1. It is known that washing machines are equipped with a dispenser of washing agents, intended as washing detergents and additive in powder and/or liquid; the latter consists typically of softeners, in the case of washers, and of rinse aids in the case of dishwashers. For example, in the case of dishwashers, the dispensers comprise usually a body of plastic material, partially recessed in the counter-door of the machine, i.e. the part of the front loading door of the machine facing the inside of the washing chamber. The cited body defines, in the front, a space for containing a detergent, usually in powder form, which is provided with a small overturning or sliding closing door; the opening of this small door is suitably controlled by a programmer, or timer, of the machine. Within the dispenser body is then equipped with a tank, for containing a second washing agent of the liquid type, typically a rinse aid; usually, the quantity of rinse aid that can loaded in said tank, which is equipped with a special plug, is enough for carrying out several washing cycles. The inside of the dispenser presents a small cup, associated with the above-mentioned tank, for dosing the quantity of rinse aid to be supplied during a washing cycle; the rinse aid dosing system uses in particular the opening and closing movement of the machine door, horizontal when it is open and vertical when it is closed, to load part of the rinse aid from the tank to the dosing cup; when the machine is operating, the programmer controls an actuator that frees a discharge opening being present in correspondence of the dosing cup, so that the dose of rinse aid can flow from the latter to the washing tank of the dishwasher. As said, in general, the capacity of the cited tank is able to contain a quantity of liquid agent which is enough for executing several washing cycles; in this way, the user of the machine has to fill the tank through the relevant plug, only at certain intervals. The dispensers as those previously mentioned are usually equipped with means for informing the user about the need of filling the cited tank with the liquid washing agent. In the most sophisticated solutions, for this reason the dispenser is equipped with a suitable electric or electronic sensor, able to detect the presence of the liquid washing agent in the tank; this sensor is properly connected to the machine control system so that the latter, should the lack of liquid washing agent be detected in the tank, enables optical and/or sound signals, like a lamp or a buzzer. This kind of solution, although being efficient, implies a decisive increase of the total cost of the dispenser, due to the presence of a sensor; also the cost of the machine that uses such a dispenser is higher, considering the need to connect properly the sensor to the control system of the machine and to the relevant signaling means. In less sophisticated solutions, a simple visual control indicator of the liquid washing agent level is associated to the tank. This indicator typically comprises a passage of circular section that extends between the tank of the liquid washing agent and the front surface of the dispenser body; an element of transparent plastic material, for example polycarbonate or methacrylate, is inserted at least partially in this passage, having a shape corresponding to that of the passage, and in particular cylindrical; by means of such a transparent element it is possible to have indications concerning the quantity of the liquid washing agent contained in the relevant tank. A dispenser of the above indicated type is, for example, represented in Fig. 1 of DE-A-195 45 773. It should however be considered that there are also known solutions in which a same dispenser is equipped with an electric/electronic level sensor as well as with a simple visual control indicator, as those mentioned previously. The annexed Fig. 1 represents, with different views, the typical known implementation of a transparent element as mentioned above, indicated as a whole with 1. As it can be noticed, the transparent element 1 presents a mainly cylindrical shape, in which an upper portion 1 A and a lower portion IB can be identified, being delimited from one another by a circular flange 2. The upper portion 1A is completely cylindrical and is destined to be inserted with interference in the relevant passage defined in the dispenser body; it should be noticed, to this purpose, that the body of a dispenser is usually made of two pieces welded together, and that the portion 1A of the transparent element 1 is inserted in the relevant passage of circular section before this welding operation, from the side being opposite to the surface that will constitute the front of the dispenser. Portion 1 A is inserted in the relevant passage until flange 2 rests on the internal surface of the dispenser body; as said, this insertion occurs with interference, and portion 1A of element 1 is equipped with a series of surface knurls 3, whose function is to avoid possible seeping of the liquid washing agent towards the external part of the tank; following the above-mentioned insertion, the front surface 4 of portion 1A flushes with the front surface of the dispenser body. The lower portion IB of the transparent element 1 is destined to be inserted inside the tank containing the liquid washing agent; as it can be noticed, at its lower end a series of projections 5 is defined, each having substantially the shape of a triangular or pentagonal prism, placed side by side and arranged like stairs steps, i.e. lying at different heights. The operation of such an indicator is very simple. When the loading door of the dishwasher is open, i.e. in the horizontal position (which is also the typical loading position of the liquid washing agent in the respective tank), the number of projections 5 that are plunged in the liquid washing agent depend on the quantity of the latter; in other words, the higher the level of the washing agent in the tank, the higher the number of projections 5 plunged in it. In effect, the transparent element 1 is realized in such a way as to transmit visually, from projections 5 to the front surface 4, an indication of the liquid washing agent level, which depends as said on the number of projections 5 that come into contact with the latter; it should be noticed also that, when the liquid washing agent is totally or partially lacking, on the surface 4 will be visible, always due to an optical effect, some horizontal lines, being representative of the longitudinal limits of the projections 5 that are not plunged in the liquid washing agent (see for example the plan view of Fig. 1); in this way, the surface 4 becomes a sort of graduated scale, whose divisions or steps are delimited by the said horizontal lines. In this way, therefore, when the door of the machine is open (a condition that inevitably precedes the start of the washing cycle), the user has the possibility to make sure about the presence or absence of the liquid washing agent and/or its level. To this purpose, consider the transparent element 1, equipped with four projections 5 and suppose that the tank of the liquid washing agent is half full. In this situation, only the two projections being most distant from the surface 4 (i.e. the first two projections 5 starting from the bottom, with reference to Fig. 1) will be plunged in the liquid washing agent. To this, an intermediate level indication corresponds on the front surface 4 of the transparent element 1 ; in particular, the lower half of the front surface 4 will have a first shade of color, due to the optical effect created by the plunging of the projections 5 in the liquid. On the contrary, the upper half of surface 4 will appear with a second shade of color, being clearer and substantially corresponding to the normal shade of color of the material forming the transparent element 1 ; on said second half a horizontal line will also be visible, also due to optical effect, that corresponds to the demarcation line between two projections 5 which are not plunged in the liquid. Although the solution described above is simple and cheap, it presents some drawbacks. A first drawback derives from the fact that, according to the known technique, the "reading" of the information deducible from the signaling indicator is not easy but rather difficult, especially when the liquid level in the relevant tank is low. Another drawback connected to the known technique is that, due to the kind of implementation of portion IB of the transparent element 1, only a limited number of projections 5 can be defined on it; as a result, the user receives just a few indications and/or with a low measurement resolution, concerning the filling of the liquid washing agent tank. In order to explain the above-mentioned drawbacks, reference can be made to the annexed Fig. 1 A, which represents the front surface 4 of the transparent element 1. As it can be noticed, the divisions of the graduated scale consisting of the front surface 4 of element 1 are visible, being represented by the parallel horizontal lines that, due to optical effect, are visible at the points of demarcation between the different projections 5. The dimensions in the vertical direction (with reference to the figure) of each division, and of the respective projection 5, which we will call step P, are equal for all projections 5; on the contrary, the dimensions in the horizontal direction of the different divisions and of the respective projections, which we will define as width, are different, since they depend on the circular-shaped section of portion IB of the element 1; in particular, the two end projections and divisions (i.e. lower and upper) present a smaller width than the maximum possible width, being indicated with L, which concerns the two central divisions and projections. As seen, therefore, due to the kind of implementation of the prior art, the overall development S of the graduated scale, given by the sum of the single steps P, will never be greater than the dimension of minimum encumbrance or width of the surface 4 (which in this case corresponds to the diameter L of said surface), on which the various steps P have to be represented. As it can be assumed, in order to allow for a satisfactory reading of the divisions of the graduated scale and an efficient interpretation of the associated level information, the step P, i.e. the relevant dimension of the projections 5, must be big enough; as said, this implies a limited measurement resolution. Apparently, in order to try to resolve the above-mentioned drawback, it would be possible to reduce the step P, i.e. the relative dimension of the projections 5, by keeping constant the diameter of the portion IB of element 1 ; in this way, the graduated scale visible on the front surface 4 of the same element 1 will present a greater number of divisions. An increase of the measurement resolution obtained in this way would imply however a definite worsening of the comprehensibility of the information deducible from the signaling indicator: it is in fact manifest that the smaller the step P of the scale divisions, the greater the difficulty of interpretation. On the other hand, the increase in the number of the projections 5, even maintaining an acceptable step P, could be allowed through an increase of the diameter of the transparent element 1. However, according to the prior art, the diameter of the section of the transparent element 1 must always be quite small; this requirement is determined also by the fact that, during manufacturing, the element 1 is in effect "hammered" in the relevant passage, with a considerable mechanical interference between the parts, in order to obtain a safe positioning and above all, ensure the required sealing. On the basis of what has been said above, it is clear that the greater the dimensions of the transparent element 1, the greater the required force that shall be, during production, to implement the positioning and ensure the sealing of the latter in the relevant passage. It should also be considered that the greater the dimensions of transparent element 1 , and hence the force required to realize its insertion with a considerable interference in the relevant seat, the greater the breaking risks of the components during production. In other words, since a considerable force must be exercised on the transparent element in order to insert it in a passage having slightly smaller dimensions (in order to ensure a mechanical seal), the probability of breaking the transparent element or the part of the dispenser body in which the passage is defined shall highly increase. Hence, for the above mentioned reasons, according to the prior art, the transparent element 1 must have a rather small section dimension. This requirement, as already mentioned previously, makes the "reading" of the information deducible from the signaling indicator difficult; the ensuing limited number of projections 5 determines a lack of indications and/or measure resolution. Another drawback of the known technique previously described is that the provision of simple knurls 3 on the external surface of the transparent element 1 , and the fact that the seal against the seeping of the liquid washing agent is obtained mechanically, result not very efficient and reliable, especially in the long run; consider, for example, that the thermal cycles that occur during the different machine washes can cause tensioning in the structure of the dispenser, giving rise to leaks from the signaling indicator; according to the known technique, such a drawback could get worse in the presence of big-sized indicators and/or having non symmetrical or complex shapes, like a stretched or curved geometry. The prior art described previously presents also other drawbacks from the production point of view. During production, in fact, the possible faultiness of the signaling indicator, in terms of lack of sealing, can be detected only during the final testing of the dispenser, i.e. when the latter is completely assembled. This means that, in case of detected defects, the main part of the dispenser will be lost, without any possibility of reusing it, in particular due to the impossibility of separating the two pieces forming the dispenser body (which are typically welded together). Even in the case of a test before assembling the two pieces of the body, neither the transparent element nor the piece of the body in which the relevant passage is defined, can be reused due to the kind of coupling, which as said assumes a high mechanical interference (in particular, both element 1 and the piece of the body will have undergone a certain deformation during the insertion of the first one in the passage defined in the second one, which makes it impossible to reuse the parts). The aim of the present invention is to resolve one or more of the above-mentioned drawbacks, and in particular to indicate a dispenser equipped with an optical control indicator that allows a more precise and reliable visual control in comparison with the known technique, in relation with the presence and/or level of liquid washing agent contained in a tank that is part of the dispenser, and whose realization is more efficient and reliable. Within this frame, a first aim of the invention is to indicate such a dispenser whose visual control indicator can be read more easily and more precisely than the prior art. Another aim of the invention is to indicate such a dispenser whose visual control indicator allows to obtain more precise information, i.e. with a higher measurement resolution than the known technique. Another aim of the invention is to indicate such a dispenser whose visual control indicator is equipped with sealing means that are more reliable than the known technique. Another aim of the invention is to indicate such a dispenser equipped with means that allow to reduce the force required to realize the coupling of a component of the visual signaling indicator in a relevant seat, in particular in order to avoid faultiness and/or breaking risks during the manufacturing. One or more of these aims are achieved, according to the present invention, by a dispenser of washing agents for a household washing machine, in particular a dishwasher, having the features of the annexed claims, which form an integral part of the present description. Further aims, features and advantages of the present invention will become apparent from the following detailed description and the annexed drawings, which are supplied by way of non limiting example, wherein: - Fig. 1 represents, with different views, a known transparent element, previously described, being part of a control indicator of the level of the liquid washing agent for a dispenser of washing agents according to the known technique; - Fig. 1A schematically represents the front surface, visible from the outside of a generic washing agents dispenser, of a transparent element of the type illustrated in Fig. 1; - Fig. 2 schematically represents, with a front view, a washing agents dispenser according to the present invention; - Fig. 3 schematically represents, with a section view according to the A - A axis of Fig. 2, a washing agents dispenser according to the present invention; - Fig. 4 represents, with different views, a transparent element being part of a control indicator of the level of liquid washing agent of a washing agents dispenser according to the present invention; - Fig. 5 schematically represents in an exploded view a portion of the washing agents dispenser of Fig. 2, inclusive of the transparent element of Fig. 4; - Figs. 6 - 9 schematically represents various possible operating conditions of the washing agents dispenser according to the present invention, by means of respective partial front views and sections according to the A - A axis of Fig. 2; - Figs. 10 - 12 represent, by means of section views similar to those of Fig. 3, with relevant magnifications, possible alternative embodiments of the washing agents dispenser according to the present invention; - Fig. 13 represents, with different views, a transparent element being part of a control indicator of the level of liquid washing agent of a washing agents dispenser according to a possible variant of the present invention; - Figs. 14 - 17 schematically represent various possible operating conditions of the transparent element of Fig. 13; - Figs. 18 - 19 represent, with different views, a variant embodiments of a transparent element being part of a washing agents dispenser according to the present invention; - Fig. 20 represents, with views from the top, the element of Figs. 18 - 19, in different operating conditions of the washing agents dispenser according to the present invention; - Figs. 21 - 24 represent, by means of respective perspective views, further possible variant embodiments of a transparent element being part of a control indicator of the level of liquid washing agent of a washing agents dispenser according to the present invention; - Figs. 25 - 26 represent, by means of respective perspective views, further possible variant embodiments of a transparent element being part of a control indicator of the level of liquid washing agent of a washing agents dispenser according to the present invention. In Figs. 2 and 3, 10 indicates as a whole a washing agents dispenser according to the present invention, which presents a box-shaped body 11 that can be housed at least partially in an opening provided in the counter-door of the washing machine door, in particular of a dishwasher; in the case of the mentioned Figs. 2 and 3, the dispenser 10 is represented in the position that it assumes when the door of the washing machine is closed. As in the prior art, the body 11 is realized by welding a front piece and a back piece, for example made of thermoplastic material, indicated in Fig. 3 with 11A and 1 IB, respectively. In the body 11, a space for containing a certain quantity of detergent powder and a tank 12 for containing a liquid washing agent are defined, a dosing cup being associated to the tank 12; the said space and cup, being per se known, are not visible in Figs. 2 and 3. 13 indicates a small overturning door or flap, for closing the cited space, which is hinged in its upper part and in a known way to part 11A of body 11; 14 indicates an opening/closing device of flap 13, whose type and operation are also known. 15 indicates the plug of an opening communicating with the tank 12, used to load the liquid washing agent in the latter. 16 indicates a discharge opening, through which the liquid washing agent contained in the relevant dosing cup being internal to body 11 can flow towards the washing chamber of the machine; the cited opening 16 is equipped with a special plunger, known per se, controlled by the machine control system, for realizing the supply of the liquid washing agent at the proper moment of a washing cycle. 17 finally indicates as a whole a transparent element, in plastic material, such as polycarbonate or methacrylate, being part of a control indicator of the level of the liquid washing agent, which is at least partially inserted in a passage defined in part 11 A of body 1 1. As it can be seen in Fig. 3, in correspondence of the cited passage, in part 11 A of body 11 an internal seat is defined, indicated with 18, which presents two sections 18A and 18B with different dimensions; in this way, a notch or relief G is defined between the two sections, whose function shall be cleared later. Transparent element 17 is represented in different views in Fig. 4, by means of views similar to those of Fig. 1. As it can be noticed, in this case the transparent element 17 presents an oblong-shaped section, i.e. having a greater dimension and a smaller dimension; in particular, in the non limiting example supplied here, the greater dimension of such a section is defined by two parallel straight lengths, which are joint at the two ends by two semicircular lengths, which realize the smaller dimension. Also in this case, in the body of the transparent element 17 an upper portion 17A and a lower portion 17B can be identified, which are delimited between them by a circular flange 19. As it can be noticed, the upper portion 17A is formed by two lengths of oblong section, having different dimensions, indicated with 17A' and 17A", between which a notch or relief Gl is defined. The lower portion 17B of the transparent element 17, also having a substantially oblong section, presents at its lower end a series of projections 20, each having substantially the shape of triangular or pentagonal prism, placed side by side and arranged like stairs steps, i.e. lying at different heights. It can be immediately noticed from Fig. 4 that, thanks to the particular oblong shape of the prevailing section of the transparent element 17, the lower portion 17B of the latter can be equipped with a greater number of projections 20, in particular six, in comparison with the case shown in Fig. 1 , even if the dimensions of the plunging section of the projections 20 (i.e. the section being perpendicular to the plunging direction) is at least equal to those of the prior art (the difference between the two cases is the dimension in height of the projections, according to the plunging direction). Fig. 5 shows, through a partial and exploded view, the assembly system of the transparent element 17 on the body of the dispenser according to the present invention. The upper portion 17A of the element 17 is intended to be inserted with a light interference, for the reasons explained later, in the relevant seat 18, from the bottom; as said, the body of the dispenser is made of two pieces 11A and 1 IB welded together, and portion 17A of the transparent element 17 is inserted in the relevant seat 18 before said welding operation, from the opposite side with respect to the surface that will be the front surface of the dispenser. Before this insertion, on the notch Gl resulting between the two lengths 17A' and 17 A" of portion 17A suitable elastic sealing means are mounted, for example an o-ring gasket, indicated in Fig. 5 with 21. At this point, portion 17A is inserted in the relevant seat, until flange 19 rests on the lower end of the seat 18; following such an insertion, the two sections 17A' and 17 A" of portion 17A result in being inserted in the respective portions of the seat 18, with the gasket 21 operating as a seal between the notch Gl defined on the same portion 17A and the notch G defined inside the seat 18 (see Fig. 3); after the above-mentioned insertion, the front surface 22 of the upper portion 17 A results substantially flush with the front surface of part 1 1A of the dispenser body. At this point, part 11 A and part 1 IB of body 1 1 are welded together, in such a way as to define inside them the tank 12 for containing the liquid washing agent, where portion 17B of the transparent element 17 is inserted; following such an assembly, the dispenser according to the present invention is as visible in Fig. 3. The special shape of portion 17B of the transparent element 17, as well as the presence of the sealing means 21 allow to obtain important advantages. First of all, as said, the dimensions of element 17 can be quite greater that the one provided by the prior art; this is allowed by the fact that, according to the invention, a considerable mechanic interference between the element 17 and the relevant seat 18 is not necessary any more. According to the invention, in fact, the seal on element 17 is further assured by the special elastic means 21. Consequently, the force required for the insertion of the element 17 in the seat 18 can be moderate and this allows as a result to realize the same element 17 with dimensions being greater than the known technique. For the same reasons, also the breaking and/or faultiness risks of assembling of the different components, during manufacturing, are extremely reduced; similarly, also in case of defects detected during testing, both element 17 and piece 1 1A of body 1 1 shall be easily uncoupled, in order to allow for their possible re-use, if necessary. It is also clear that, according to the invention, the seal on element 17 is improved through the special elastic sealing means 21, with manifest advantages in terms of efficiency and reliability of the sealing system as to the known technique. The particular shape of the lower portion 17B of the transparent element 17, as well as its greater dimensions, make the reading of the information deducible from the signaling indicator considerably easier; the fact that in the same element 17 a greater number of projections 20 can be defined with respect to the prior art (even if the step defined by these projections 20 is in the order of that of the known appendages 5) results in the fact that the user can receive more information, with a high measurement resolution, concerning the filling of tank 12 of the liquid washing agent. For this reason, in Figs. 6 - 9 are schematically represented different possible operating conditions of the washing agents dispenser according to the present invention, by means of respective partial front views and sections, according to the A - A axis of Fig. 2; it should be noticed that in the case of the said Figs. 6 and 9, the dispenser 10 is represented in the position that it assumes when the door of the washing machine is closed. In the case of Fig. 6, the tank 12 contains the maximum quantity of liquid washing agent possible; as noticed in the upper part of said figure, all projections 20 of the transparent element 17 are therefore plunged in the liquid washing agent, indicated with B. To this corresponds, as noticed in the lower part of the same figure, a maximum indication of level on a graduated scale of the front surface 22 of the transparent element 17; in particular, this front surface 22 will have completely a first shade of color, due to the optical effect created by the plunging of all projections 20 in the liquid. In the case of Fig. 7, the tank 12 is half filled; as noticed in the upper part of this figure, only the three projections 20 being most distant from surface 22 (i.e. the first three projections 20 starting from the bottom, with reference to the figure) are plunged in the liquid washing agent B. To this corresponds, as noticed in the lower part of the same figure, an intermediate indication of level on the front surface 22 of the transparent element 17; in particular, this front surface 22 shall have for approximately half of its development in length the mentioned first shade of color, as determined above, and for approximately half it will appear with a second shade of color, clearer and corresponding to the normal one of the material forming the transparent element 17. It should be noticed that on this second half of the surface 22 will be visible also, due to the optical effect, the demarcation lines between the projections 20 which are not plunged in the liquid washing agent, i.e. the different divisions of the mentioned graduated scale. In the case of Fig. 8, the tank 12 is filled very little; as noticed in the upper part of this figure, only the projection 20 being most distant from the surface 22 (i.e. the first projection 20 starting from the bottom, with reference to the figure) is plunged in the liquid washing agent B. To this corresponds, as noticed in the lower part of the same figure, a minimum indication of level on the front surface 22 of the transparent element 17; this front surface 22 will have, in particular, for approximately one sixth of its development in length the mentioned first shade of color, and for approximately five sixths it will appear with the mentioned second shade of color, and with the relevant lines or divisions of scale. Finally, in the case of Fig. 9, a little more than one third of tank 12 is filled and in the particular case in which, as noticed in the upper part of the figure, the two projections 20 being most distant from the surface 22 are completely plunged in the liquid washing agent B, while the cusp of the third projection 20 is plunged only partially. In this case, and as noticed in the lower part of the same figure, a particular indication of level appears on the front surface 22 of the transparent element 17; in fact: a) two sixths of the development in length of the front surface 22 will have the mentioned first shade of color, b) a small central portion of one sixth of the development in length of the front surface 22 will appear with the mentioned first shade of color, and the remaining side portions will appear with the mentioned second shade of color (this is due to the fact that, as said, the third projection 20 starting from the right is plunged only partially in the liquid B); c) the remaining half of the development in length of the front surface 22 will appear completely with the mentioned second shade of color. Obviously, also in this case the lines or divisions of the graduated scale constituted by the surface 22 will be visible, for all those projections 20 that are not completely plunged in the liquid. It should be noticed that, in case of transparent elements according to the known technique as the one described in Fig. 1, the situation indicated previously is very frequent, since the number of projections 5 is very limited; this means that, according to the prior art, even when the tank containing the liquid washing agent contains, for example, a bit less than one third, the indication supplied by the transparent element will be similar to that as of previous letter b), but it will not be easily identifiable due to the reduced dimensions. In other words, according to the prior art, even in the presence of an important quantity of liquid washing agent, the visual indication available is difficult to be read, or the measurement resolution is reduced; vice versa, in the case of the present invention, due to the availability of a greater number of projections (which also have greater dimensions), more easily readable indications are available, with the possibility of detecting easily level fractions that concern the same division of a graduated scale. Figs. 10 - 12 describe some possible variant embodiments of the present invention, whose aims are to further reduce or remove the need of mechanical interference between the element 17 and the relevant seat 18. In case of Fig. 10, flexible wings 30 are defined inside part 1 1A of body 11 and sideways with respect to the seat 18; as noticed, these wings 30 present at their free end a hooking tooth 31 whose external surface defines an inclined plane 32. The assembly of the transparent element 17 is in this case realized by pushing the transparent element 17 towards the inside of the seat 18; at a certain point of this insertion movement, the flange 19 enters into contact with the inclined plane 32 of tooth 31, determining an outward bending of wings 30. When, proceeding with the insertion movement, the flange 19 surpasses the tooth 31 and a predefined compression is obtained of the sealing element 21 in its working position, the wings 30 return in a flexible way in the initial position; in this way, teeth 31 are seized on the rear surface of the flange 19, as shown in the enlarged part of Fig. 10: in such a situation, the opposing elastic reaction of the sealing element 21 is countered by the locking condition of the flange 19 with respect to teeth 31. As it can be assumed, with this kind of snap-in coupling, the need of mechanical interference between the element 17 and the internal surfaces of seat 18 can be extremely reduced, or at best eliminated, since the seal is ensured through the element 21. It should be noticed that, if necessary, the above-mentioned components can be uncoupled by simply determining an outward bending of wings 30. In the case of Fig. 11, in the free end of portion 18A of the seat 18 an extension is defined, indicated with 40, which forms a sort of a notch with respect to the section of housing 18. The assembly of the transparent element 17 is realized by pushing the transparent element 17 inside of the seat 18, until the flange 19 reaches the notch defined in correspondence of the extension 40; in this condition, a predefined compression of the sealing element 21 is obtained in the working position. At this point, keeping element 17 in the reached position, the extension 40 is bent, in particular through hot riveting or heading, towards the inside of seat 18 and against flangel9; after ending this operation, the flange 19 is locked between the said notch and the bent part of the extension 40, as shown in the enlarged part of Fig. 11. As it can be assumed, also in this case the need of mechanical interference between the element 17 and the internal surfaces of the seat 18 can be reduced or at best eliminated, since the seal is ensured through the element 21 ; if necessary, the above-mentioned components can be uncoupled by reversing the previous operations, or by determining the breaking of the extension 40. It is clear that, instead of a single extension that surrounds the free internal end of the seat 18, several alternate extensions can be provided. In the case of Fig. 12, at the free end of portion 18B of the seat 18 an extension 50 is defined, that ends with an inclined plane 51 ; hooking openings 52 are formed in this extension 50. In this case, the upper surface of the flange 19 (i.e. the surface intended to face the seat 18) is tilted in the same direction as the plane 51. The assembly of the transparent element 17 is realized by pushing the same inside the seat 18; at a certain point of this insertion movement, the tilted surface of the flange 19 enters into contact with the inclined plane 51 of the extension 50, determining an outward bending of the latter. When, proceeding with the insertion movement, the flange 19 reaches the hooking openings 52 and a predefined compression is obtained of the sealing element 21 in its working position, the extension 50 returns in a flexible way to the initial position, in such a way as to lock flange 19 in the same openings 52, as shown in the enlarged part of Fig. 12; in such a situation, the opposing elastic reaction of the sealing element 21 is countered by the locking condition of the flange 19 with respect to the openings 52. As it can be assumed, also with this kind of snap in coupling, the need of mechanical interference between the element 17 and the internal surfaces of the seat 18 can be reduced or at best eliminated, since the seal is ensured through the element 21. Also in this case, the above-mentioned components can be uncoupled by simply determining an outward bending of the extension(s) 50. Fig. 13 represents with different views a possible alternative embodiment of a transparent element, for the use in the dispenser according to the present invention. Also in this case, in the transparent element 60 an upper portion 60A and a lower portion 60B can be identified, which are delimited between themselves by a circular flange 61. As it can be noticed, the upper portion 60A is formed by two lengths having circular sections having different diameters, indicated with 60A' and 60A", between which a notch or relief Gl ' is defined. The lower portion 60B of the transparent element 60 consists substantially of a protrusion departing toward the bottom from the lower surface of the flange 61 ; the said protrusion 62 is bent and its height grows from one end to the other, i.e. its lower edge (the one opposing flange 61) is helicoidal type; in the case illustrated in the figure, the bending of protrusion 62 follows part of the circumference of the overhanging flange 61 for about 240°. The lower edge, having the helicoidal course, of protrusion 62 is practically defined by a series of projections 63, which have substantially a triangular or pentagonal prism shape, placed side by side and lying at different heights, i.e. like steps, forming a sort of "helicoidal stairs". It can be immediately noticed from Fig. 13 that, thanks to the particular shape of the lower portion 60B, the latter can be equipped with a greater number of projections 63, in particular eight, in comparison with the case shown in Fig. 1 ; it should be noticed that this is allowed even if the steps of projections 63 is equal to the step P of projections 5 according to the prior art, and the maximum diameter of the portion 60A or of the flange 61 is equal to those of the prior art, and indicated in Fig. 1 with 1 A and 2, respectively. The transparent element 60 is realized, as already mentioned previously, in such a way as to transmit visually, from projections 63 to the front surface 64, an indication of the level of the liquid washing agent, which depends on the number of projections 63 that are in contact with the latter; when the liquid washing agent is totally or partially lacking, the surface 64 shows, always due to an optical effect, the divisions of a graduated scale, defined by the edges of the projections 63 that are not plunged in the liquid washing agent. However, in the specific case of the transparent element 60, these divisions will not consist of lines being parallel to each other, as in the case of Fig. 1A, but of sections placed radially, i.e. flaked like slices to form a circular sector, indicated with SC in Figs. 14 - 17, described later. Considering that the diameter of the portion 60A of the transparent element 60 can be reduced, its mounting system can be the same as provided according to the current state of the art, i.e. based on an important mechanical interference between the transparent element 60 and the relevant seat in the dispenser body. Nothing prevents in any case from providing, also for the transparent element 60, an assembly system being similar to the one described previously with reference to Fig. 5, i.e. based on a moderate mechanical interference and on the use of elastic sealing means, for example an o-ring, intended for positioning in correspondence of the notch Gl ' (Fig. 13). For this case, the seat 18 of Fig. 5 will have a shape being congruent with that of the upper portion 60A of the transparent element 60, i.e. it will have two lengths with different diameters (consonant with those of lengths 60A' and 60A" of the portion 60A), to define a positioning notch or relief for the said elastic sealing means; the upper portion 60A of the element 60 can therefore be inserted with a moderate interference in the relevant seat, from the bottom, for the reasons already explained. Apart from the chosen assembly system, the particular shape of the lower portion 60B of the transparent element 60 is advantageous. As said, in fact, even if the dimensions of the element 60 and of the step of the projections 63 equal those provided by the known technique (Fig. 1 - 1A), the proposed variant allows to put at the user's disposal more information, with a high measurement resolution concerning the filling of the tank of the liquid washing agent. For this reason, Fig. 14 - 17 schematically represent various possible operating conditions of the transparent element 60, through respective front views. In the case of Fig. 14, as in Fig. 6, the tank of the dispenser contains the maximum quantity of liquid washing agent as possible; in this situation, all the projections 63 of the transparent element 60 are plunged in the liquid washing agent. To this corresponds, as noticed in Fig. 14, an indication of maximum level on the front surface 64 of the transparent element 60; in particular, the part SC shaped as a circular sector on which the divisions of the graduated scale placed radially would be visible, will have a first shade of color due to the optical effect created by the plunging of projections 63 in the liquid; the remaining part of the front surface 64 will appear with a second shade of color, that is clearer and substantially corresponds to the normal shade of color of the material (for example polycarbonate or methacrylate) forming the transparent element 60. In the case of Fig. 15, as in Fig. 7, the tank of the dispenser is half filled; in this situation, only the four projections 63 being most distant from the surface 64 (i.e. the first four projections 63 starting from the top, with reference to the right view of Fig. 13) are plunged in the liquid washing agent. To this corresponds, as noticed in Fig. 15, an intermediate indication of level on the front surface 64 of the transparent element 60; in particular, the first half (about 120°, which corresponds to four divisions) of the part SC shaped as a circular sector will have the said first shade of color, while the second half of the part SC will have the said second shade of color, on which, due to optical effect, the radial divisions will be visible corresponding to the projections 63 which are not plunged in the liquid washing agent; also the remaining part of the front surface 64 will appear with the same second shade of color. In the case of Fig. 16, as in Fig. 8, the tank of the dispenser is filled very little; in this situation, only the projection 63 being most distant from surface 64 (i.e. the first projection 63 starting from the top, with reference to the right view of Fig. 13) is plunged in the liquid washing agent. To this corresponds, as noticed in Fig. 16, a minimum level indication on the front surface 64 of the transparent element 60; in particular, only one eighth (about 30°, which corresponds to one division) of the part SC shaped as a circular sector will have the said first shade of color, while the remaining seven eighths of the part SC will have the said second shade of color, allowing to view, due to optical effect, the radial divisions indicating the projections 63 not plunged in the liquid washing agent; also the remaining part of the front surface 64 will appear with the same second shade of color. Finally, in the case of Fig. 17, as in Fig. 9, a little more than a half of the dispenser tank is filled and in the particular case in which the four projections 63 being most distant from the surface 64 are completely plunged in the liquid washing agent, while the cusp of the fifth projection 63 is plunged only partially therein. In this condition, as noticed in Fig. 17, a particular indication of level appears on the front surface 64 of the transparent element 60; in fact: a) four eighths (about 120°, which corresponds to four divisions) of the part SC shaped as a circular sector will have the said first shade of color, b) a small central portion of the subsequent one eighth of the part SC will appear with the above-mentioned first shade of color, and the remaining side portions will appear with the above-mentioned second shade of color (this is due to the fact that, as said, the fifth projection 63 is plunged only partially in the liquid); c) the remaining three eighths (about 90°, which correspond to three divisions) of the part SC will have the above-mentioned second shade of color; d) the remaining part of the front surface 64 will appear with the same second shade of color. It can be noticed from the above that in the case of the embodiment of Fig. 13, the display of the graduated scale and of the information that can be deduced from it, is realized on a limited area (SC) of the visible surface 64 of the element 60, under procedures that are excellent from the operating point of view as well as the aspect. From the above description, as well as from the annexed claims, which form an integral part of it, the features of the present invention are clear. In particular, a dispenser of washing agents has been described for a household washing machine, in particular a dishwasher, which comprises a tank for containing a liquid washing agent; a visual control device of the liquid washing agent level is associated to said tank, which comprises a passage, placed between the tank and the external part of the dispenser body, and an element made of transparent material, which is inserted in this passage. A first portion of the transparent element is at least partially visible from the outside of the dispenser body, and the second portion is inserted in the tank; the free end of the second portion defines a plurality of projections placed at different heights, and different steps of a scale indicating the level of the liquid washing agent in the tank can be seen on at least one area of the visible surface of the first portion. Each of the above-mentioned steps corresponds to a projection and can assume at least two different shades of color, according to the fact that the relevant projection is plunged or not in the liquid washing agent, in order to provide for a visual indication of level on the said scale. According to the invention, the overall development of the above-mentioned scale, meant as the sum of the single steps, is greater than its dimension of minimum encumbrance, or width, that can be detected on the said visible surface. From the description and the attached drawings the advantages of the invention are also clear. In particular, in the described dispenser: - the visual control indicator is easier to read and more precise with respect to the known technique; - the visual control indicator allows to obtain more precise information, i.e. having a higher measurement resolution than the known technique; - the visual control indicator can be equipped with sealing means that are more reliable than the known technique; - the force required to realize the coupling of a component of the visual signaling indicator in the relevant seat can be possibly moderate, in order to avoid faultiness and/or breaking risks during manufacturing. It is clear that many changes are possible for the man skilled in the art to the washing agents dispenser for a household washing machine, in particular a dishwasher, described as an example, without departing from the novelty spirit of the inventive idea. For example, in order to increase the sealing characteristics against seepage, the transparent element 17 can be equipped with knurls, in addition to the sealing means 21. It is also clear that the prevailing section of the transparent element 17, or of its parts, can be different than the one described previously, without changing the greater development of the graduated scale with respect to the known technique, i.e. having a greater dimension (or length) and a smaller dimension (width); for example, the section of the transparent element 17 could be oval or rectangular; in this second case, the sealing means 21 could be square-rings instead of o-rings, or be shaped in such a way as to fit the relevant positioning points provided by the transparent element and by the relative seat. Obviously, also the geometry of the projections 20 can be different from the one described previously by way of example, as long as it is proper for the provided objects. Inter alia, the possibility is pointed out of realizing the coupling between the transparent element and the relevant seat through pasting or welding, for example by ultrasound or other similar known fixing systems. Fig. 18 - 20 represent, with different views, a variant embodiment of a transparent element being part of a washing agents dispenser according to the present invention. According to the proposed variant embodiment, said transparent element is shaped as a plug, indicated with 115, realized in such a way as to integrate directly a level signaling indicator of the liquid washing agent in the relative tank. Plug 115, which is for the purpose realized at least partially with transparent material (for example methacrylate or polycarbonate), presents an upper part 1 15 A, realized in a known manner and therefore presenting coupling and tightening means 115B in a relevant opening provided on the dispenser body, communicating with the tank of the liquid washing agent; the part 115A presents also a groove 115C, for receiving a ring gasket, not represented in the figures, to guarantee the required sealing. It should be noticed that, in the example, the said coupling and tightening means 1 15B are of the bayonet joint type, but it is clear that they may be of another type (for example of the threaded type). 115D indicates a seizing element, that rises from the upper part 115A, which is provided for making easier the tightening and removal operations of plug 115 from its seat; as noticed, the seizing element 115D presents substantially an oblong section. According to the proposed variant, from part 115 A of plug 115 a lower portion 115E departs, in order to enter the tank of the liquid washing agent. As noticed, also this lower portion 115E presents a prevailing oblong section, along the smaller sides of which steps are defined, each having substantially a triangular or pentagonal prism shape, or having anyway a reduced section, lying at different heights; as noticed, in the example, there are provided three pairs of steps 120 A lying at the same height, and a central terminal step 120B. As it can be assumed, steps 120 A and 120B accomplish the same function of the projection indicated previously with 20 or 63. From Fig. 18 - 19 it is then possible to notice how the seizing element 115D and the lower portion 115E are mainly aligned together; considering that plug 115 is realized in transparent material, it is possible to understand how it allows to obtain the same advantages of the invention declared previously, concerning the signaling quality of the level of the liquid washing agent. It is in fact clear that, also in the case of the proposed variant, it will be possible to have a level indication on a graduated scale given by the front surface 115D' of the seizing element 115D; also in this case, the front surface 115D' can assume the above-mentioned first and second shades of color, depending upon the number of steps 120A-120B plunged in the liquid washing agent contained in the tank. In fact, for example: - if the tank is full, all the steps 120A-120B are plunged in the liquid washing agent; to this corresponds a maximum indication of level on the front surface 115D'; in particular, this front surface will have the first shade of color, as noticed in part A of Fig. 20; if the tank is full for about 3 A, only the central step 120B and the subsequent two pairs of steps 120A from the bottom will be plunged in the liquid; to this corresponds an intermediate indication of level on the front surface 115D'; in particular, one part equal to about 3 /4 of said front surface 1 15D' will have the first shade of color, while the remaining part of the same surface will have the second shade of color; as noticed in part B of Fig. 20, the area having the first shade of color will be highlighted in an intermediate portion of the surface 115D', while the second shade of color will be visible at the two ends of the surface 115D'; if the tank is about half full, only the central step 120B and the subsequent two pairs of steps 120A from the bottom will be plunged in the liquid; to this corresponds an intermediate indication of level on the front surface 115D'; in particular, approximately half of said front surface 115D' will have the first shade of color, while the remaining part of the same surface will have the second shade of color; as noticed in part C of Fig. 20, the area having the first shade of color will be highlighted in an intermediate portion of the surface 115D', having an extension that is more reduced than the one mentioned for the previous situation (tank 3 A full - part B of Fig. 20); conversely, the second shade of color, visible at the two ends of surface 115D', will have a greater extension compared to the situation previously mentioned with reference to part B of Fig. 20; - if about a quarter of the tank is full, or if it is at its minimum level, only the central step 120B will be plunged in the liquid; to this corresponds a minimum indication of level on the front surface 115D'; in particular, about one quarter of this front surface 115D' will have the first shade of color, while the remaining part will have the second shade of color; also in this case, as noticed in part D of Fig. 20, the area having the first shade of color will be highlighted in an intermediate portion of the surface 115D', but will have quite a lower extension than the one mentioned for the previous situations (parts B and C of Fig. 20); conversely, the second shade of color, being visible at the two ends of the surface 1 15D', will have quite a greater extension if compared to the previous situations. It can be deduced from the above how in the case of the proposed variant the user is informed about the reduction of the liquid washing agent level by the gradual "reduction in size", towards the center of the front surface 1 15D', of the area having the first shade of color and the corresponding gradual "extension in size", at the ends of the front surface 115D', of the area having the second shade of color. Moreover, it should be noticed that the signal system of the plug 115 according to the proposed variant can also be different from the one described by way of example; from this point of view, for example, the lower portion of the plug 115 can be configured as the lower portion 17B of the transparent element 17 of Figs. 4 - 5, or as the lower portion 60B of the transparent element 60 of Fig. 13. According to another variant, not represented here, the plug equipped with the level signaling indicator can be realized in separate parts, instead of a single piece; for example, the plug could comprise a first opaque portion, having the required coupling and tightening means 115B and the groove 115C, and equipped with a central through-opening, within which a transparent element configured substantially as the element 17 of Fig. 5 is inserted in a sealed way or "hammered" with mechanical interference; in said variant, the length 17A' of the upper portion 17A of the transparent element 17 could realize, besides the level signaling graduated scale, also the seizing means required to facilitate the removal and tightening operations of the plug in the relevant housing. Fig. 21 - 24 represent further possible variant embodiments of a transparent element being part of a control indicator of the level of the liquid washing agent of a washing agents dispenser according to the present invention. Please note that these figures use the same reference numbers of the previous figures, for indicating technically equivalent elements. The transparent elements of the variant embodiments of Figs. 21 and 22, indicated with 117A and 117B respectively, derive substantially from the transparent element 17 of Figs. 4 - 5; however, as it can be noticed, in the case of the proposed variants, the front surface of the transparent elements 117 A and 117B is not continuous (like surface 22 of element 17 of Fig. 4 and 5), but appropriately shaped in order to supply more precise level indications. In particular, in the case of Fig. 21, the upper surface of the transparent element 117A presents reliefs RC having a cylindrical section, while in the case of Fig. 22 on the upper surface of the transparent element 117 A grooves SN are defined, that divide the same surface into several zones 122. As it can be noticed from these figures, the reliefs RC and the zones 122 are aligned with respective projections 20 defined in the lower portion of the transparent elements 117A and 117B; conversely, the free spaces existing between reliefs RC and grooves SN defined between the zones 122 are substantially aligned with the demarcation lines among the said projections 20. In accordance with the embodiments of Fig. 21 and 22, the upper end of the seat intended for receiving the transparent element 1 17A or 117B (i.e. the end being defined in correspondence of the front surface of the dispenser) does not present a single opening, as in the case of the seat 18 of Fig. 5, but a plurality of openings, whose number and shape correspond to the reliefs RC or to the zones 122, and fit for receiving said reliefs or zones. In this case, therefore, the graduated scale indicating the level of the liquid washing agent will consist of a series of steps, realized by the front surfaces of reliefs RC or areas 122 which are visible outside the dispenser body, which are clearly separated from one another since they are marked off by the same material forming the dispenser body. In another variant not represented here, reliefs RC or zones 122 could be separated from each other by means of an opaque piece being different from the dispenser body, for example hammered or co-molded; for this case, the upper end of the seat that will receive the transparent element 117A or 117B, presents a single opening, as in the case of seat 18 of Fig. 5. The transparent elements of the variant embodiments of Fig. 23 and 24, indicated with 117C and 117D respectively, derive substantially from the transparent element 1 17A of Fig. 21 and from the transparent element 1 17B of Fig. 22, respectively. What changes, in this case, is the shape of the projections 20, which are not configured anymore as steps or projections placed side by side and defined along an edge of the lower portion of the transparent element. In the case of Fig. 23, the projections 20 are distinct and consist of cylindrical parts having a section consonant with that of the reliefs RC, which departs downwards, under the intermediate flange 19 of the transparent element 117C. The same is valid for the case of Fig. 24, where the distinct projections 20 consist of parts having a quadrangular section, whose dimensions are consonant with those of the zones 122, departing downwards, under the intermediate flange 19 of the transparent element 1 17D. As it can be noticed, in both cases, the distinct projections 20 present a sharp end, or anyway having a reduced section. On the other hand, it is manifest how the seat that have to receive the transparent elements 117C and 117D as of Fig. 22 and 23 is similar to the one previously described for elements 117A and 1 17B; it is also manifest that the operating principle, for signaling the level of the liquid washing agent, is similar. It can be deduced from the above how, also in the case of the variants of Figs. 21 - 24, the length of the scale indicating the level of the liquid washing agent, meant as the sum of the single steps forming it, is greater in comparison with its width. Figs. 25 - 26 represent further possible variants of a transparent element being part of a control indicator of the level of liquid washing agent of a washing agents dispenser according to the present invention; also these figures use the same reference numbers of the previous figures to indicate technically equivalent elements. The transparent elements as of the variants of Figs. 25 and 26, indicated with 1 17E and 1 17F respectively, derive substantially from the transparent element 17A of Figs. 4 - 5; however, as it can be noticed, in the case of the proposed variants, on the front surface 22 of the transparent element 117E raised numbers NR are defined, while on the front surface 22 of the transparent element 117D raised letters LR are defined. As it can be noticed from these figures, the numbers RN or the letters LR are aligned with respective projections 20 defined in the lower portion 17B of the transparent elements 117E and 117F; conversely, the free spaces existing between these numbers or letters are substantially aligned with the demarcation lines among the said projections 20. Also in this case, the upper end of the seat that will receive the transparent element 1 17E or 117F (i.e. the end present in correspondence with the front surface of the dispenser) does not present a single opening, as in the case of housing 18 of Fig. 5, but a plurality of openings whose number and shapes correspond to the numbers NR or letters LR, and fit for receiving the latter ones. In this case, therefore, the graduated scale indicating the level of the liquid washing agent will consist of a series of steps, realized by the front surfaces of the number RC or the letters LR being visible outside the dispenser body, which are clearly separated from one another since they are marked off by the same material forming the dispenser body. In the example of Fig. 25, the cited graduated scale consists of the series of numbers "6", "5", "4", "3", "2" and "1", where in particular the number indicates the level of the liquid washing agent (in the example, "6" corresponds to a full tank, and "1" corresponds to the minimum level); in the case of Fig. 26, the said graduated scale consists of a series of characters, for example forming a word (in the example, the word is "LEVEL"). Obviously, the assembly process of the transparent elements 117E and 117F according to the offered variant embodiments is substantially the one already described before; similarly, the operation of the dispenser, for signaling the level of the liquid washing agent, is exactly the same as described previously. Obviously, in alternative embodiments, on the front surface 22 of the transparent element can be define, instead of numbers or letters, symbols or different kind of figures, or a combination of alphanumeric characters. As it can be assumed, also the variant of Figs. 25 - 26 is particularly advantageous, both for what concerns the possibility of managing several aesthetic variants of the dispenser and for what concerns the quality of the level signaling; in this case, in fact, besides the signaling which consists of the different shades of color that the different letters or numbers or symbols have according to the quantity of washing agent being available, the user also receives a more direct information. Finally, it must be pointed out that, regardless of the shape of the reliefs RC, zones 122, letters or numbers or symbols NR - LR, the required sealing is always ensured by means of at least one part of the upper portion of the transparent elements, for example having an oval section and fit to be inserted in the respective seat, operating in sealing by means of a gasket and/or through a mechanical interference, as already previously mentioned. If the ends of the projections destined to be plunged in the liquid washing agent are conical or truncate cone shaped, their taper will be preferably of 90° (i.e., for example, in case of conical shape, this will derive from the revolution of a right-angled triangle whose angle related to the cone vertex is 45°); in case of prismatic ends, or similar, two opposing end faces will be inclined at 90° from one another.

Claims: CLAIMS 1. Dispenser of washing agents for a household washing machine, in particular a dishwasher; said dispenser (10) comprising a tank (12) for containing a liquid washing agent to which a visual control device (17-18;60) is associated, of the level of said liquid washing agent, said control device comprising a passage (18), placed between said tank (12) and the external part of the body (11) of the dispenser (10), and an element in a substantially transparent material (17;60) being inserted in said passage (18), where - a first portion (17A;60A) of said transparent element (17;60) is at least partially visible from the outside of said body (1 1) and a second portion (17B;60B) of said transparent element (17;60) results in being inserted in said tank (12), - at the free end of said second portion (17B;60B) a plurality of projections (20;63) is defined, being arranged at different levels of height, and on at least a zone of the visible surface (22;64) of said first portion (17A) the steps can be recognized, of a scale indicating the level of said liquid washing agent in said tank(12), each of said steps corresponds to one of said projections (20;63) and can assume at least two different shades of color, depending on the fact that the relative projection (20;63) is dipped or not in the liquid washing agent, in order to provide a relevant visual indication of level on said scale, characterized in that the overall development of said scale, being meat as the sum of the single steps, is greater than the dimension of minimum encumbrance, or width, of said scale that can be detected on said visible surface (22;64). 2. Dispenser, according to claim 1, characterized in that at least one section (17B;60B) of said transparent element (17;60) presents an oblong section or a greater dimension and a smaller dimension. 3. Dispenser, according to claim 2, characterized in that, at least in correspondence of the point of said second portion (17B;60B) from which the longest of said projections (20;63) departs, the overall section of said transparent element (17;60) is oblong or presenting a greater dimension and a smaller dimension, in particular in order to provide for a greater number of said projections (20;63) with respect to that being possible for a circular section, in order to have information on the level of the said liquid that are more precise and/or having a higher measurement resolution. 4. Dispenser, according to claim 2 or 3, characterized in that, in correspondence of said first portion (17A) the section of said transparent element (17) is oblong or presenting a greater dimension and a smaller dimension, in particular in order to allow for an easier and more precise comprehensibility of the information supplied by said device (17-18) for the visual control of the level of said liquid. 5. Dispenser, according to at least one of the previous claims, characterized in that the section of at least a zone of said transparent element (17) presents two parallel straight length segment, being joint at the two ends by two semicircular segment. 6. Dispenser, according to claim 1, characterized in that said projections (63) are placed side by side according to a non-rectilinear direction and/or said second portion (60B) presents a non-rectilinear section. 7. Dispenser, according to claim 1, characterized in that the overall development of the zone of said second portion (60B) from which these projections depart is at least partially round. 8. Dispenser, according to claim 1, characterized in that said projections (63) are placed side by side in an at least partially helicoidal way. 9. Dispenser, according to at least one of the previous claims, characterized in that said second portion (60B) has substantially the shape of an overhang (62) with a growing height and at least partially bent, on whose inclined edge said projections (63) are defined. 10. Dispenser, according to at least one of the previous claims, characterized in that at least some of said steps are delimited by lines being substantially horizontal and parallel, highlighted due to optical effect on said visible surface (22). 1 1. Dispenser, according to at least one of the claims from 1 to 9, characterized in that the steps of said scale are highlighted due to optical effect in the shape of radial sectors placed side by side, like slices, on a zone (SC) of said visible surface (64), said area (SC) being substantially shaped as a circular sector. 12. Dispenser, according to one or more of the previous claims, characterized in that sealing means (21) of the elastic type are provided, operating between said passage (18) and said transparent element (17;60), where said passage (18) and said transparent element (17;60) are equipped with respective positioning means (G,G1;G1 ') of said sealing means (21) in the working position. 13. Dispenser, according to the previous claim, characterized in that said sealing means (21) are designed for adapting to the shape of said positioning means (G,G1 ;G1 '), and comprise in particular a ring gasket (21). 14. Dispenser, according to claim 1 , characterized in that said passage (18) presents at least two sections (18A, 18B) having different dimensions. 15. Dispenser, according to claims 12 and 14, characterized in that said positioning means of said passage (18) comprise a notch or relief (G) defined between said two sections (18A.18B). 16. Dispenser, according to claim 1, characterized in that a flange (19;61) is defined between said first portion (17A;60A) and said second portion (17B;60B) of said transparent element (17;60). 17. Dispenser, according to claim 1, characterized in that said first portion (17A;60A) is formed by at least of two lengths (17A',17A";60A',60A") having different sections. 18. Dispenser, according to claims 12 and 17, characterized in that said positioning means of said transparent element (17;60) comprise a notch or relief (G1 ;G1 ') defined between said two lengths (17A',17A";60A',60A"). 19. Dispenser, according to one or more of the previous claims, characterized in that said projections (20;63) have substantially a triangular or pentagonal prism shape. 20. Dispenser, according to one or more of the previous claims, characterized in that the number of said projections (20) is greater than four. 21. Dispenser, according to claim 1, characterized in that said transparent element (17;60) is coupled to the said passage (18) through a moderate mechanical interference between the parts. 22. Dispenser, according to claim 1, characterized in that snapping or flexible coupling means (30;50) are provided for maintaining the correct working position of said transparent element (17) within said passage (18). 23. Device, according to claim 22, characterized in that said couplers (30;50) comprise at least one flexible wing (30), being equipped with at least one hooking tooth (31). 24. Device, according to the previous claim, characterized in that said hooking tooth (31) presents at least an inclined plane, operable for being brought into contact with one part (19) of said transparent element (17), during the assembly of the latter in said passage (18), in order to produce a bending of said wing (30). 25. Device, according to claim 23, characterized in that said tooth (31) is capable of hooking on said part (19) of said transparent element (17), in a condition of compression of said sealing means (21). 26. Device, according to claim 22, characterized in that said hooking means (30;50) comprise at least a flexible portion (50) associated to said passage (18) in which at least one hooking opening (52) is defined, said flexible portion (50) presenting in particular an inclined plane (51) at the free end. 27. Device, according to the previous claim, characterized in that said transparent element (17) comprises a raised part (19) having at least one inclined surface. 28. Device, according to claims 26 and 27, characterized in that said inclined surface of said raised part (19) can be brought into contact with said inclined plane (51) of said flexible portion (50), during the assembly of said transparent element (17) within said passage (18), for producing a bending of said flexible portion (50). 29. Device, according to claims 26 and 27, characterized in that said hooking openings (52) are capable of retaining said raised part (19) of said transparent element (17), in a condition of compression of said sealing means (21). 30. Device, according to claim 1, characterized in that, in order to maintain the correct working position of said transparent element (17) within said passage (18), a mechanical deformation of at least an end area (40) of said passage (18) is provided. 31. Device, according to the previous claim, characterized in that said area (40) is deformed towards the inside of said passage (18), against at least one part (19) of said transparent element (17), in order to lock the latter mechanically, in a condition of compression of said sealing means (21). 32. Device, according to the previous claim, characterized in that said deformation is executed through hot-riveting or hot-heading of said area (40). 33. Dispenser, according to at least one of the previous claims, characterized in that said transparent element (17;60) is realized with a plastic material, like polycarbonate or methacrylate. 34. Dispenser, according to at least one of the previous claims, characterized in that the prevailing section of said transparent element (17) has substantially an oval or rectangular shape. 35. Dispenser, according to at least one of the previous claims, characterized in that said sealing means (21) comprise an o-ring or a square-ring. 36. Dispenser, according to at least one of the previous claims, characterized in that the coupling between said passage(18) and said transparent element (17;60) is realized through pasting or welding, in particular through ultrasound or similar fixing technique. 37. Dispenser, according to at least one of the previous claims, characterized in that said body (11) is realized by welding a front piece (11A) and a rear piece (1 IB). 38. Dispenser, according to at least one of the previous claims, characterized in that said body (11) has an opening that contains a second washing agent, equipped with a relative door (13). 39. Dispenser of at least a washing agent, for a household washing machine, in particular a dishwasher; said dispenser (10) comprising a tank (12) for containing a liquid washing agent, to which a visual control device (17-18;60) is associated of the level of said liquid, said control device comprising a passage (18), placed between said tank (12) and the external part of the body (11) of the dispenser (10), and an element in a substantially transparent material (17;60) being inserted in said passage (18), a first portion (22;64) of said transparent element (17;60) being at least partially visible from the outside of said body (11) and the second portion (17B;60B) of said transparent element (17;60) being inserted in the said tank (12), where at the free end of said second portion (17B;60B) a series of projections (20;63) is defined, being placed at different levels of height, characterized in that at least one length of said transparent element (17;60) presents a section having an oblong shape or a greater dimension and a smaller dimension. 40. Dispenser of at least one washing agent, for a household washing machine, in particular a dishwasher; said dispenser (10) comprising a tank (12) for containing a liquid to which a visual control device (17-18 ;60) is associated of the level of said liquid, said control device comprising a passage (18), placed between said tank (12) and the external part of the body (11) of the dispenser (10), and an element in a substantially transparent material (17;60) inserted in said passage (18), a first portion (22;64) of said transparent element (17;60) being at least partially visible from the outside of said body (11) and a second portion (17B;60B) of said transparent element (17;60) being inserted in said tank (12), where at the free end of said second portion (17B;60B) a series of projections (20;63) is defined, being placed at different levels of height, characterized in that elastic sealing means (21) are provided, working between said passage (18) and said transparent element (17;60), where said passage (18) and said transparent element (17;60) are equipped of respective means (G,G1 ;G1 ') for positioning said sealing means (21) in the working position. 41. Dispenser of at least one washing agent, for a household washing machine, in particular a dishwasher; said dispenser (10) comprising a tank (12) for containing a liquid to which is associated a visual control device (17-18;60) of the level of said liquid, said control device comprising a passage (18), placed between said tank (12) and the external part of the body (11) of the dispenser (10), and an element in a substantially transparent material (17;60) inserted in said passage (18), a first portion (22;64) of said transparent element (17;60) being at least partially visible from the outside of said body (11) and a second portion (17B;60B) of said transparent element (17;60) being inserted in said tank (12), where at the free end of said second portion (17B;60B) a series of projections (20;63) is defined, being placed at different levels of height, characterized in that said projections (63) are placed side by side according to a non-rectilinear direction, where in particular the overall development of the zone of said second portion (60B) from which said projections (63) depart is at least partially bent and/or said projections (63) are placed side by side in an at least partially helicoidal way. 42. Dispenser of washing agents for a household washing machine, in particular a dishwasher; said dispenser (10) comprising a tank (12) for containing a liquid washing agent to which a visual control device (17-18;60) is associated of the level of said liquid washing agent, said control device comprising a passage (18), placed between said tank (12) and the external part of the body (11) of the dispenser (10), and an element in a substantially transparent material (17;60) inserted within said passage (18), - where a first portion (17A;60A) of said transparent element (17;60) is at least partially visible from the outside of said body (11) and a second portion (17B;60B) of said transparent element (17;60) is inserted in said tank (12), - at the free end of said second portion (17B;60B) a plurality of projections (20;63) is defines, being placed at different levels of height, and on at least one area of the visible surface (22;64) of said first portion (17A) the various steps of a scale can be recognized, for indicating the level of said liquid washing agent in said tank(12), - each of said steps corresponds to one of said projections (20;63) and can assume at least two different shades of color, depending upon the fact that the corresponding projection (20;63) is dipped or not in said liquid washing agent, in order to provide for a visual indication of level on said scale, characterized in that said pitches of said scale are highlighted by optical effect in the shape of radial sectors placed side by side, like slices, on at least one area (SC) of said visible surface (64), said area (SC) having in particular a shape which is at least partly bent. 43. Dispenser, according to claim 1, characterized in that said transparent element is integrated in, or is part of, a cap (1 15) of said tank (12). 44. Dispenser, according to the previous claim, characterized in that said transparent element is realized as a single piece with said cap (115). 45. Dispenser, according to claim 43, characterized in that said transparent element is inserted and/or integral with said cap (115). 46. Dispenser, according to at least one of the previous claims, characterized in that said cap (115) present an upper seizing means (115D), which is substantially aligned with said projections (120A,120B). 47. Dispenser, according to the previous claim, characterized in that said seizing means (115D) is formed at least partially by said transparent element. 48. Dispenser, according to claim 1, characterized in that said visible surface of said first portion presents reliefs (RC). 49. Dispenser, according to claim 1, characterized in that said visible surface of said first portion presents interruptions (SN), which divide said visible surface into several separate areas (122). 50. Dispenser, according to claim 48 or 49, characterized in that said reliefs (RC) or said separate areas (122) are substantially aligned with respective projections (20). 51. Dispenser, according to at least one of claims from 48 to 50, characterized in that the upper end of said passage (18) presents a plurality of openings, whose number and shape correspond to said reliefs (RC) or to said separate area (122), said scale being realized by the surfaces of said reliefs (RC) or said separate areas (122) being visible outside said body (1 1), the steps of said scale being clearly separated from each other by opaque material and/or forming said body (11). 52. Dispenser, according to at least one of the previous claims, characterized in that said projections (20) are formed by distinct parts of said second portion, said parts having in particular a circular or polygonal section. 53. Dispenser, according to claim 1, characterized in that said visible surface of said first portion is at least partially shaped to define numbers and/or symbols and/or figures and/or alphabetic or alphanumeric characters. 54. Dispenser, according to the previous claim, characterized in that said numbers and/or symbols and/or figures and/or alphabetic or alphanumeric characters are substantially aligned with respective projections (20). 55. Dispenser, according to claim 53 or 54, characterized in that the upper end of said passage (18) is shaped accordingly to said numbers and/or symbols and/or figures and/or alphabetic or alphanumeric characters. 56. Dispenser, according to at least one of the claims from 53 to 55, characterized in that said scale is realized by the surfaces of said numbers and/or symbols and/or figures and/or alphabetic or alphanumeric characters being visible on the outside of said body (11), the steps of said scale being clearly separated from one another by opaque material and/or forming said body (11). 57. Dispenser, according to at least one of the previous claims, characterized in that at least some of said projections (120A) are arranged in pairs, the two projections (120A) of each pair laying at the same height, the various pairs laying at different heights. 58. Dispenser, according to at least one of the previous claims, characterized in that the reduction of the liquid washing agent level is highlighted by the gradual reduction in size, towards the center of said visible surface (115D'), of an area having a first shade of color and the corresponding gradual extension of an area of said visible surface (115D') having a second shade of color. 59. Dispenser, according to at least one of the previous claims, characterized in that, in case of conical or truncated cone shape, the ends of said projections present a taper of 90°, or present two opposing faces being inclined at 90°.

Inventors: NEBBIA FABIO, PERUCCA GIOVANNI, NEBBIA, FABIO, PERUCCA, GIOVANNI
Applicants: ELTEK SPA, NEBBIA FABIO, PERUCCA GIOVANNI, ELTEK S.P.A., NEBBIA, FABIO, PERUCCA, GIOVANNI
Application year: 2000
Main classification: A47L15
IPC codes: A47L15, G01F23