Patent Publication Number: US-11647887-B2

Title: Gasket for dishwasher, dishwasher including such gasket and associated assembly method

Description:
FIELD OF THE INVENTION 
     The present invention relates to the manufacturing of seals used in dishwashers. In particular, the present invention relates to a seal which may be associated with the door of a dishwasher to prevent washing water and/or steam losses during normal washing operations. 
     The invention also relates to a dishwasher comprising such seal and to a method for assembling the seal on the dishwasher. 
     BACKGROUND ART 
     In the context of the manufacturing of dishwashers, the use of water and/or steam sealing seals ensuring a correct dishwasher operation is widely known. Dishwashers of the known type conventionally comprise a reception tub with a front opening inside which the cookware to be washed is positioned. 
     A door, conventionally hinged below and rotatable about a usually horizontal axis, opens/closes the front opening of the tub. 
     A perimeter seal is advantageously applied on the front edges of the opening, usually at the upper edge and at the two side edges, with the function of preventing washing water and/or steam from escaping from the dishwasher with the door closed during normal washing operations. 
     The solutions relating to seals of the known type comprise an extruded rubber profile, for example in EPDM, cut to size and inserted manually by pressure inside a seat made at the side edges of the front opening. 
     The insertion seat conventionally consists of a channel with a U-shaped open section which peripherally develops on the three sides of interest of the opening. The channel is conventionally obtained by welding a folded stainless steel profile on the outer sides of the dishwasher tub so that one side of the U-channel consists of the wall of the tub on which the folded profile is welded and the other two sides of the U-channel consist of the folded profile itself. 
     The seal assembly operations involve the preparation of the folded profile, the welding of the folded profile on the outer sides of the tub to create the U-shaped peripheral channel, preferably by means of a robot, and the manual insertion of the seal into the peripheral channel. 
     To facilitate the operations of inserting the seal into the channel by the operator, it is often necessary to employ various types of lubricants, for example, using talc or a solution of water and glycerin. 
     A first drawback in said assembly operations is due to the use of said lubricating products which introduce dirt on the assembly line. 
     During the life of the dishwasher, replacing the seal may also be required, in case of damage or loss of performance thereof. 
     The replacement of the seal involves a step of removing the old seal with the extraction thereof from the channel and the manual introduction of the new seal inside the channel. The insertion of the seal into the channel by the operator requires, again, the use of lubricants as mentioned above. 
     It is therefore the object of the present invention to overcome, at least partially, the drawbacks of the background art. 
     In particular, it is an object of the present invention to propose a seal for dishwashers which allows reducing assembly times and/or costs with respect to dishwashers of the known type. 
     It is another object of the present invention to propose a seal for dishwashers which allows simplifying assembly operations with respect to dishwashers of the known type. 
     It is another object of the present invention to allow the correct mounting of the seal by means of automatic assembly, preferably with robots, thus eliminating the human factor. 
     It is a further object of the present invention to propose a seal for dishwashers which allows avoiding the use of lubricants in assembly operations with respect to dishwashers of the known type. 
     Not least, it is an object to provide a seal which is reliable and easy to manufacture at competitive costs. 
     SUMMARY 
     The present invention is based on the general consideration of manufacturing a seal provided with a metal part. 
     In a first aspect thereof, the present invention therefore relates to a seal for dishwashers adapted to be interposed between a peripheral edge of an opening of a tub for cookware and a door for closing said opening, wherein the seal comprises: 
     a metal part adapted to be connected (fastened) to said peripheral edge of said opening; 
     a first part made of polymeric material integrally connected to said metal part and a second part made of polymeric material associated with said first part and adapted to be engaged resting and/or in thrust by said door when said door is arranged in the position for closing said opening. 
     In a preferred embodiment, the metal part comprises a first portion for the connection to the first part made of polymeric material and a second portion adapted for the connection (fastening) to the peripheral edge of the opening of the tub. 
     According to a preferred embodiment, the first portion of the metal part and the first part made of polymeric material are integrally connected by means of a co-extrusion process. 
     Preferably, the first portion of the metal part is embedded in the first part made of polymeric material. 
     In a preferred embodiment, the second portion of the metal part is connectable to the peripheral edge of the opening by means of a clinching process. 
     Preferably, the first part made of polymeric material and/or the second part made of polymeric material are made of EPDM and/or silicone material. 
     In a preferred embodiment, the polymeric material of the first part and the polymeric material of the second part are different polymeric materials. According to a preferred embodiment, the polymeric material of the first part has a greater hardness with respect to the polymeric material of the second part. Preferably, the first part made of polymeric material and the second part made of polymeric material form an integral single body. 
     In a preferred embodiment, the seal comprises a transition zone between the first part made of polymeric material and the second part made of polymeric material, said transition zone being adapted to be divided to remove the second part made of polymeric material from the first part made of polymeric material. 
     According to a preferred embodiment, the first part made of polymeric material comprises a hollow and closed inner zone. 
     Preferably, the hollow and closed inner zone is configured so that the dividing operation at the transition zone affects the hollow inner zone transforming said hollow inner zone into an open seat adapted to receive a projecting part of the second part made of polymeric material. 
     Preferably, the second part made of polymeric material is removably associated with the first part made of polymeric material. 
     In a preferred embodiment, the seal comprises connection means for the connection of the second part made of polymeric material to the first part made of polymeric material. 
     According to a preferred embodiment, the connection means comprise a seat of the first part made of polymeric material and a projecting part of the second part made of polymeric material adapted to be inserted, preferably by mechanical interference, in said seat. 
     In a preferred embodiment, the first portion of the metal part comprises a laminar portion and the second portion of the metal part comprises a laminar portion, said laminar portions being arranged in an L-shape. 
     According to another preferred embodiment, the first portion of the metal part comprises a laminar portion and the second portion of the metal part comprises a laminar portion, said laminar portions being aligned. 
     According to another preferred embodiment, the first portion of the metal part comprises two laminar portions arranged in an L-shape. 
     In a preferred embodiment, the metal part comprises a pre-cut zone adapted to make said metal part locally flexible. 
     In a second aspect thereof, the present invention relates to a dishwasher comprising a seal adapted to be interposed between a peripheral edge of an opening of a tub for cookware and a door for closing said opening, in which the seal is manufactured according to what has been described above. 
     In a third aspect thereof, the present invention relates to a method for manufacturing a seal according to what has been described above and the assembly thereof to a peripheral edge of an opening of a tub for cookware of a dishwasher, in which the method comprises the steps of: 
     integrally joining said first part made of polymeric material with said metal part to manufacture said seal comprising said metal part, said first part made of polymeric material and said second part made of polymeric material; 
     joining (fastening) said metal part of said seal to said peripheral edge. 
     In a preferred embodiment of the method, the step of integrally joining the first part made of polymeric material to the metal part is obtained by means of a co-extrusion process. 
     Preferably, the step of joining (fastening) the metal part of the seal to the peripheral edge is obtained by means of a clinching process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To better understand the features and advantages of the invention, non-limiting examples of practical embodiments thereof are described below with reference to the attached drawings in which corresponding or equivalent features and/or component parts of the present invention are identified by the same reference numerals. In particular, in the Figures: 
         FIG.  1    shows an axonometric view of a dishwasher and a seal according to a preferred embodiment of the present invention; 
         FIG.  2    shows an axonometric view of a section of the seal of  FIG.  1   ; 
         FIG.  3    shows an exploded view of the seal of  FIG.  2   ; 
         FIG.  4    shows a sectional view of the seal in the assembled position in the dishwasher with the door closed of  FIG.  1   ; 
         FIG.  5    shows a first embodiment variant of the seal of  FIG.  4   ; 
         FIGS.  6  to  9    show a second embodiment variant of the seal of  FIG.  4    and different configurations during the use thereof; 
         FIGS.  10  to  13    show a third embodiment variant of the seal of  FIG.  4    and different configurations during the use thereof; 
         FIGS.  14  to  17    show a fourth embodiment variant of the seal of  FIG.  4    and different configurations during the use thereof; 
         FIG.  18    shows a plan view of an embodiment variant of an element of the seal of  FIG.  10   . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the present invention is described below with reference to the preferred embodiments thereof depicted in the drawings, the present invention is not limited to the embodiments described below and depicted in the drawings. On the contrary, the embodiments described and depicted clarify some aspects of the present invention, the general scope of which is defined by the claims. 
     The present invention has proved to be particularly advantageous with reference to the manufacturing of a seal for a dishwasher of the standard type, i.e. a dishwasher with front opening and door hinged at the bottom, built-in or stand alone, as better shown below. 
     It should however be noted that the present invention is not limited to the manufacturing of a seal for a dishwasher of this type. On the contrary, the present invention finds convenient application in dishwashers with any type of opening configuration and corresponding door. 
       FIG.  1    shows a dishwasher  1  comprising a seal  20  according to a preferred embodiment of the present invention and, with reference to  FIGS.  1  to  4   , the seal  20  according to the preferred embodiment of the present invention is shown and described. 
     The dishwasher  1  preferably comprises an outer support structure  4 , preferably of a parallelepiped shape, and a tub  6  with a front opening  10  for receiving the cookware to be washed. 
     A door  12  is hinged to the support structure  4  for closing the front opening  10 . The door  12  is preferably hinged below, the door  12  being, in particular, rotatable about a substantially horizontal axis. 
     According to an aspect of the present invention, a perimeter seal  20  is applied to corresponding portions  14   a ,  14   b ,  14   c  of the inner surfaces of the tub  6 , in particular, of the inner surfaces of the side and opposite walls and of the upper wall of the tub  6 . Each of the portions  14   a ,  14   b  and  14   c  therefore face towards the inside of the tub  6 , wherein the portions  14   a  and  14   c  mutually face each other (one opposite the other), and wherein the portions  14   a  and  14   c  are mutually connected by the portion  14   b , the portions  14   a ,  14   b  and  14   c  being further positioned near the outer edge of the tub  6 , and therefore of the front opening  10 . In the preferred embodiment shown and described herein, the perimeter seal  20  shows, in general, a three-sided shape, substantially an inverted U shape, to be applied to the corresponding three peripheral portions  14   a ,  14   b ,  14   c . It is evident that in embodiment variants, the shape and the number of peripheral edges or portions and the corresponding shape of the seal may be different from what is shown herein. 
     According to an aspect of the present invention, the seal  20  comprises a metal part  30  adapted to be connected (fastened) to the corresponding peripheral portion  14   a ,  14   b ,  14   c  of the tub  6  near the opening  10 , a first part  40  made of polymeric material and a second part  50  made of polymeric material. The second part  50  made of polymeric material is adapted to be engaged in thrust or at least resting on the door  12  when the door is arranged in the position for closing the opening  10 , as it may be observed in  FIG.  4   . 
     The first part  40  made of polymeric material is integrally connected to the metal part  30 . 
     Furthermore, preferably, the first part  40  made of polymeric material and the second part  50  made of polymeric material form an integral single body. The metal part  30  comprises a first portion  32  for the connection to the first part  40  made of polymeric material and a second portion  34  adapted for the connection (fastening) to the corresponding portion  14   a ,  14   b ,  14   c.    
     In a preferred embodiment, the first portion  32  of the metal part  30  and the first part  40  made of polymeric material are integrally connected by means of a co-extrusion process. 
     The first portion  32  of the metal part  30  is preferably embedded in the first part  40  made of polymeric material. 
     More preferably, the entire seal  20 , i.e., the metal part  30 , the first part  40  and the second part  50  made of polymeric material are manufactured by means of a co-extrusion process. 
     The first part  40  is advantageously provided with sealing flaps  42  adapted to be arranged in abutment against the peripheral edge or surface portion  14   a ,  14   b ,  14   c  to improve the adhesion of the seal  20  to the peripheral edge or portion  14   a ,  14   b ,  14   c.    
     The second part  50  is advantageously provided with a sealing portion  52  designed to ensure the hydraulic seal against the escape of liquid/steam from the tub  6  during operation. 
     The polymeric material of the first part  40  and/or the polymeric material of the second part  50  is preferably EPDM. Alternatively, TPE thermoplastic rubbers, of the TPE-S, TPE-V, TPE-U type, or silicon may also be used. 
     In an embodiment variant, the second part  50  preferably comprises closed cell foam rubber. 
     In a preferred embodiment, the polymeric material of the first part  40  is selected so as to have a greater hardness with respect to the polymeric material of the second part  50 . 
     In preferred embodiment variants, however, the first part  40  and the second part  50  may have the same hardness. 
     A greater hardness for the first part  40  ensures a greater structural seal of the first part  40  itself while a lower hardness for the second part  50  ensures a better hydraulic seal of the second part  50  itself. A better hydraulic seal is also ensured in the case of using a closed cell foam rubber for the second part  50 . 
     To improve the sealing, elasticity and weight features of the second part  50 , the same is made in a tubular shape. Alternatively, the second part  50  may have an open configuration, substantially defining a lip shape. 
     Preferably, the polymeric material of the first part  40  has a hardness from 70 to 95 Shore A, more preferably a hardness from 80 to 90 Shore A. 
     Preferably, the polymeric material of the second part  50  has a hardness from 30 to 70 Shore A, more preferably a hardness from 40 to 60 Shore A. 
     Preferably, in the case of using closed cell foam rubber for the second part  50 , the density of the second part  50  is preferably from 0.35 gr/cm 3  to 0.95 gr/cm 3 . 
     The metal part  30  is preferably made of steel, preferably of a material adapted to be used in a clinching process. The metal part  30  is generally and preferably made of the same metal material used for the manufacturing of the tub  6 . In the preferred embodiment shown, the first portion  32  of the metal part  30  comprises two laminar portions arranged in an L-shape and the second portion  34  of the metal part  30  comprises a laminar portion. 
     As a whole, the metal part  30  shows a substantially S-shape, as better visible in  FIG.  3    and  FIG.  4   , wherein, with particular reference to  FIG.  4   , it is possible to appreciate that, by virtue of the substantially S-shape, the laminar portion  34  is adapted to be fastened to the peripheral edge  14   a ,  14   b ,  14   c , the first laminar portion of the portion  32  extends from the laminar portion  34  along a direction substantially perpendicular to the extension direction of the portion  34 , the second laminar portion of the portion  32  extends along a direction substantially perpendicular to the first laminar portion of the portion  32  and substantially parallel to the extension direction of the portion  34 . 
     In embodiment variants, however, the metal part may have different shapes, as shown and described below with reference to  FIGS.  10  to  18   , wherein, according to the present invention, in the case of an S-shaped metal part, the angle between the first laminar portion of the portion  32  and the portion  34 , and the angle between the second laminar portion and the first laminar portion of the portion  32  may vary. 
     The seal according to the invention allows simplifying the dishwasher manufacturing operations. 
     First of all, the seal  20  is made by integrally joining the first part made of polymeric material  40  and the second part  50 , associated therewith, to the metal part  30  to manufacture the seal  20 . 
     Such joining is preferably but not exclusively obtained by means of a co-extrusion process. 
     The seal  20  thus manufactured is then connected to the peripheral edges or portions  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 . 
     The connection is made by fastening the metal part  30  to the peripheral edges  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 , in particular by fastening or, in general, by connecting the second portion  34  of the metal part  30  to the peripheral edges  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 . 
     Such fastening or joining is preferably obtained by means of a clinching process. In embodiment variants different joining processes may be used, for example a spot welding process. 
     Advantageously, the operations for manufacturing and assembling the seal to the dishwasher are simplified with respect to the systems of the known type. The result is a reduction in the corresponding assembly times and/or costs with respect to the dishwashers of the known type. 
     Furthermore, advantageously, said steps may be carried out allowing the repeatability of the positioning during the assembly. Furthermore, advantageously, said steps do not involve the use of any lubricating substance in use in the background art to facilitate the insertion of the seal in the prepared seat. 
     With reference to  FIG.  5   , a first embodiment variant of a seal  120  according to the invention is described. 
     Features and/or component parts corresponding or equivalent to those of the previous embodiment are identified by the same reference numerals. 
     The seal  120  differs from the seal  20 , described with reference to  FIGS.  1  to  4   , in that the second part  150  made of polymeric material is removably associated with the first part  140  made of polymeric material. 
     Connection means  160  allow the connection of the second part  150  made of polymeric material to the first part  140  made of polymeric material. 
     The connection means  160  preferably comprise a seat  162  made in the first part  140  made of polymeric material and a projecting part  164  of the second part  150  made of polymeric material adapted to be inserted by mechanical interference in such seat  162 . 
     The projecting part  164  is preferably provided with elastic flaps  164   a  adapted to facilitate the insertion and seal of the second part  150  made of polymeric material and the first part  140  made of polymeric material. 
     With regard to the features of the first and second parts  140 ,  150 , such as, for example, the type of material and/or the hardness thereof, what has been described above with reference to the first embodiment is valid. 
     Also the seal  120  according to such embodiment allows simplifying the dishwasher manufacturing operations. 
     In a first embodiment method, the assembly consisting of the first part made of polymeric material  140  and the metal part  30  is made, preferably by means of a co-extrusion process. 
     The assembly thus made is then connected (fastened or applied) to the peripheral edges  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 . 
     The connection is made by joining the metal part  30  to the peripheral edges  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 , preferably by clinching as described above. 
     The second part  150  made of polymeric material is therefore connected by mechanical interference to the first part  140  made of polymeric material. In an embodiment variant, the second part  150  made of polymeric material is first connected by mechanical interference to the first part  140  made of polymeric material of the assembly and therefore the complete seal  120  is connected to the peripheral edges  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 . 
     A further advantageous aspect of such embodiment, in addition to those already mentioned with reference to the first embodiment, derive from the detachability features of the second part  150  made of polymeric material which allows the removal thereof with respect to the first part  140  made of polymeric material, to be, for example, easily replaced with a new spare second part. 
     This allows reducing the times and/or the maintenance costs due to damage or loss of performance of the seal  120  over time. 
     With reference to  FIGS.  6  to  9   , a second embodiment variant of a seal  220  according to the invention is described. 
     Features and/or component parts corresponding or equivalent to those of the previous embodiments are identified by the same reference numerals. The seal  220  differs from the seal  20 , described with reference to  FIGS.  1  to  4   , in that the first part  240  made of polymeric material comprises a hollow inner zone  250 . 
     Furthermore, a transition zone  260  is identified between the first part  240  made of polymeric material and the second part  50  made of polymeric material. 
     The transition zone  260 , preferably made by reducing the thickness of the material, defines a zone adapted to be divided to remove the second part  50  made of polymeric material from the first part  240  made of polymeric material, as shown in  FIG.  7   . 
     The division is preferably carried out by cutting, for example, with a cutter. Advantageously, following the dividing operation, the hollow inner zone  250  of the first part  240  made of polymeric material, originally closed or blind, becomes an open seat  162 , of the type previously shown in  FIG.  5   . 
     Such open seat  162  is advantageously shaped to receive a projecting part  164  of a second part  150  made of polymeric material adapted to be inserted by mechanical interference, for example against opposing protrusions or ridges  166  formed in such seat  162 , as shown in  FIGS.  8  and  9   . In a first advantageous aspect, such embodiment involves the manufacturing and the assembly of the seal  220  in substantially the same manner described above with reference to the first embodiment, allowing obtaining all the mentioned advantages. 
     Furthermore, in a further advantageous aspect thereof, the seal  220  allows reducing the times and/or the maintenance costs due to damage or loss of performance over time of the seal  220 , in particular of the second part  50  made of polymeric material. 
     In fact, in the case of a maintenance intervention on the seal  220 , it will be sufficient to remove the second part  50  made of polymeric material from the first part  240  ( FIG.  7   ), preferably by cutting it at the transition zone  260 , to be easily replaced with a new second part  150  ( FIGS.  8  and  9   ). 
     With reference to  FIGS.  10  to  13   , a third embodiment variant of a seal  320  according to the invention is described. 
     Features and/or component parts corresponding or equivalent to those of the previous embodiments are identified by the same reference numerals. The seal  320  differs from the seal  220  described with reference to  FIGS.  6  to  9    in the different shape of the metal part  330 . 
     The metal part  330  comprises a first portion  332  consisting of a laminar portion and a second portion  334  consisting of a laminar portion, said laminar portions  332 ,  334  being contiguously aligned, or substantially aligned, wherein, as shown, the first portion  332  may extend from the second portion  334  along an extension direction different from the extension direction of the second portion  334 , and therefore so as to define two angles, an outer one (at the top in  FIGS.  12  and  13   ) greater than 180°, and an inner one (at the bottom in  FIGS.  12  and  13   ) lesser than 180°. 
     Thereby, the fastening of the portion  334  to the portion or edge  14   a ,  14   b ,  14   c , results in the positioning of the portion  332  at a set distance (variable according to the aforesaid angles) from the portion or edge  14   a ,  14   b ,  14   c , the fastening, therefore, being not hindered by the sealing flaps  42  which may therefore be positioned resting against the portion or edge  14   a ,  14   b ,  14   c.    
     The metal part  330  has a substantially flat bar shape. 
     The remaining features, as well as the maintenance steps, are shown in  FIGS.  11  to  13   , which substantially correspond to what has been described above with reference to the second embodiment shown in  FIGS.  7  to  9   . 
     With reference to  FIGS.  14  to  17   , a fourth embodiment variant of a seal  420  according to the invention is described. 
     Features and/or component parts corresponding or equivalent to those of the previous embodiments are identified by the same reference numerals. The seal  420  differs from the seal  220  described with reference to  FIGS.  6  to  9    in the different shape of the metal part  430 . 
     The metal part  430  comprises a first portion  432  consisting of a laminar portion and a second portion  434  consisting of a laminar portion, said laminar portions  432 ,  434  being arranged in an L-shape, or substantially perpendicular to each other, the angle defined by the portions  432  and  434  being capable of varying according to needs and/or circumstances, the inner angle, in particular, being capable of varying from 90° to 150°. 
     It is noted that the seal according to the invention, in the various embodiments, may be made in a single piece ready for assembly, such as, for example, shown in  FIG.  1    in which the seal is formed by an inverted U-shaped single piece. In embodiment variants, sections of different shapes and/or different lengths may be provided, for example, three sections which are assembled at the respective peripheral edges  14   a ,  14   b ,  14   c  of the opening  10  of the tub  6 . 
     In the manufacturing of the seal in which a curvature thereof is provided, for example, two 90° bends for the abovementioned inverted U-shape, the metal part may be suitably configured to favor the curvature/deformation thereof. 
     In a preferred embodiment, for example, the metal part may be pre-cut completely or only locally at the curvature zone, so as to make the metal part more flexible and allow the curvature of the seal. 
     A possible embodiment which uses such technique is shown in  FIG.  18   . The metal part  330 ′ shown in  FIG.  18    constitutes an embodiment variant of the metal part  330 , or flat bar, shown in the seal  320  of  FIGS.  10  to  13   . 
     The metal part  330 ′ differs from the metal part  330  described above in that it comprises a localized pre-cut zone  350 . 
     The pre-cut zone  350  makes the metal part  330 ′ locally flexible and allows the curvature thereof and the curvature of the seal in which it is used. 
     It has therefore been demonstrated by means of the present description that the seal according to the present invention allows achieving the set objects. In particular, the seal according to the present invention is preferably assembled by an automated system to allow the correct position in assembly, preferably by means of a robot, this further allowing reducing assembly times and/or costs with respect to dishwashers of the known type. 
     Although the present invention has been previously clarified by means of the detailed description of some embodiments depicted in the drawings, the present invention is not limited to the embodiments described above and depicted in the drawings; on the contrary, further variants of the embodiments described are within the scope of the present invention, scope defined by the claims.