Device for a dishwasher

Abstract: This invention relates to a device for a dishwasher comprising a tub in which the dish is inserted. The tub is placed on a torsion stiff shell structure (10, 22) a part of the shell being the bottom of the tub.

Description: This invention relates to a device for a dishwasher and in particular to the design of the chassis of such a machine. Dishwashers are usually manufactured by mounting a tub comprising a bottom, three walls and roof part form sheet metal plates on a base which is manufactured by joining several beams and/or metal plates by bending-, welding- or screwing-operations to form a support on which the outer shell, if any, and surrounding equipment is fastened. The method is troublesome and timeconsuming and has the drawback that it is very difficult to achieve a construction which has sufficient stiffness depending i.e. on plays in the large number of joints combining the different parts. Thus the handling during transportation between producer and customer often means that distortions and yeldings appear between the details of the machine. It is also previously known, see DE 2 420 302 to design the dishwasher so that the upper part of the tub, which is produced from a metal plate, is placed on a base of foamed plastic, a labyrinth seal being placed between said parts. According to this arrangement pumps and the necessary surrounding equipment are integrated with the base. The advantaqe of this arrangement is said to be that mounting is facilitated. The patent publication does not however describe a method for increasing the rigidity of the machine. In order to facilitate the mounting of dishwashers it is also previously known, see EP 243 632, to produce an upwardly open base box this box being made of plastic and having means integrated with the box to keep the surrounding equipment in the box, the box moreover serving as a collecting container for water which uncontrolled flows out from the dishwasher. The tub is placed above the box and is pivotly supported on a shaft. However this design does not provide a solution to the stiffness problem mentioned above. The purpose of this invention is to achieve a design creating an increased stiffness of the complete dishwasher and also to facilitate the mounting of the tub on the base which means that water, if any, leaking out between the two parts is directed back to the tub. This is achieved by means of a device having the technical features defined in the characterising part of claim 1. Various modifications of the device are defined in the dependent claims. An embodiment of the invention will now be described with reference to the accompanying drawing where Fig. 1 is an exploded view of the device according to the present invention whereas Fig. 2 in an enlarged scale is a detailed section of the lower part of the side wall of the tub when the parts have been mounted to each other. As appears from the Figures the dishwasher comprises a base part 10 and an upper part 11 of a tub enclosing baskets, not shown, on which the dish is stored and one or several rotating wash arms, not shown. The upper part 11 has two side walls 12, a rear wall 13 and a roof part 14. The lower part of each side wall 12 has a projecting flange 15 with holes 16 for fastening the upper part to the base part. The upper part 11 preferably consists of stainless steel or plastic and has an outwardly directed lange 17 surrounding the opening of the tub. The opening of the tub is as usual provided with a door, not shown, the door being supported on dowels 18 arranged at each side of the base part 10. The base part 10 is the main element of a stiff shell structure with an upper mainly horizontal, rectangular plate 19 which is the bottom of the tub. This plate continues into vertical side wall parts 20 and to a front and rear wall part 21 joined to the vertical side wall parts. The plate 19 and the wall parts 20 and 21 together form a single unit preferably of plastic and having the shape of a downwardly open box, the opening of the box being covered by a lower horizontal plate 22 having holes 23 by means of which the plate with the aid of screws, not shown, or other means is fixed to the base part 10. These joints have to be free from any play thereby forming a very stiff shell structure in which the necessary surrounding equipment, not shown, such as circulation pump, drain pump and so on is placed. The upper plate 19 slopes towards a hopper-like part 24 which is covered by a sieve, not shown, and continues into a sump 25 in which the water is collected before it leaves to the circulation or drain pump. The plate has at the side edges and at the rear edge a vertical, flange 26 which is produced in one piece with the plate 19. At the front edge there is a smaller flange 27 which via a curved part 28 continues into the plate 19. Further at each side edge of the plate 19 there is a seat 29 with fastening holes 30 in which the upper part 11 can be joined to the base part 10 by means of screws 31. The seat is provided with a ridge 32 the distance between the ridge and the flange 26 being such that the upper part 11 with the flange 15 fits therebetween. The seat 29 at the interior side of the tub continues into a path 33 on which wheels belonging to a basket are supported. The upper plate 19 will surrounding flanges 26 and 27 thus forms a tray in which the upper part 11 of the tub is placed which means that water, if any, leaking out between the two parts is directed back to the tub. It should be mentioned that it is of course possible to design the shell structure or the upper part of the tub and the shell structure as one single unit in case a suitable production technology can be chosen. It is also possible to provide openings in the shell structure as long as the sizes and positions of the openings do not have any serious influence on the stiffness of the structure.

Claims: Device for a dishwasher comprising a tub in which the dish is inserted, characterized in that the upper part of the tub is shaped as a box which is open at the front and at the bottom and is placed on torsion stiff shell structure (10, 22) a part of the shell being the bottom of the tub. Device according to claim 1, characterized in that the shell structure is boxshaped and comprises an upper and a lower mainly horizontal plate (19 and 22, respectively) the upper plate (19) being the bottom of the tub, said plates being joined to each other via mainly vertical wall parts (20, 21). Device according to claim 2, characterized in that the upper plate (19) and the wall parts (20, 21) constitute one single detail preferably of plastic. Device according to claim 3, characterized in that the lower plate (22) is secured to said detail by means of screw joints. Device according to any of claims 2-4, characterized in that the edge of the upper plate (19) is provided with an, upwardly directed flange (26, 27). Device according to claim 5, characterized in that the upper plate (19) is mainly rectuangular, the flange (26) at three of the edges of the rectangle being higher than at the fourth edge. Device according to any of claims 5-6, characterized in that the upper part of the tub comprises vertical walls (12, 13) which are fastened at said shell structure inside said flange (26, 27). Device according to any of the preceding claims, characterized in that the upper plate (19) is provided with a sump (25) the plate at least partly sloping towards the sump. Device according to any of the preceding claims, characterized in that the shell structure (10, 22) encloses equipment belonging to the dishwasher. Device according to claim 1, characterized in that the upper part of the tub and the shell structure are one single piece.

Inventors: WRANGBERTH JAN STELLAN, WRANGBERTH, JAN STELLAN
Applicants: ELECTROLUX AB, AKTIEBOLAGET ELECTROLUX
Application year: 1991
Main classification: A47L15
IPC codes: A47L15