Abstract:
A hinge for wings or doors, in particular for electrical household appliances, comprises a first element ( 2 ) and a second element ( 3 ) pivoted to each other and movable relative to each other in tilting fashion, a connecting lever ( 5 ) between the elements ( 2, 3 ), the lever ( 5 ) pivoting on the first element ( 2 ), the second element ( 3 ) being box-shaped and comprising inside it a spring ( 7 ) connected to the lever ( 5 ) by a drive rod ( 8 ) which can slide at least partly inside the second box-shaped element ( 3 ) itself.

Description:
This application claims priority to Italian Patent Application BO2010A000218 filed Apr. 9, 2010, the entirety of which is incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     This invention relates to a hinge for doors or wings, in particular for connecting the door of an electrical household appliance. 
     More specifically, the invention relates to a hinge for electrical household appliances such as dishwashers, etc., where the appliance doors or wings are designed to support additional covering elements such as panels or the like. 
     This specification describes this invention with reference to a front-opening household appliance such as a dishwasher purely by way of a non-limiting example. 
     Hinges of this type normally consist of two separate parts kinematically linked to each other, either directly or through an interposed lever. 
     More specifically, the first part, which is usually box shaped, is fixed to the appliance structure on one side of its front opening, whilst the second part is fixed to an edge of the appliance door which can thus be tilt opened with respect to the front opening. 
     One or more elastic elements are interposed between the two hinge parts. 
     Basically, the purpose of the elastic elements is to at least partly balance the door, especially to prevent the door from falling when opened. 
     Precisely to avoid risky accelerations of the door, especially during its opening movement when the action of the user is summed to the force weight of the door itself, the prior art teaches the use, in addition to the elastic elements, of friction elements capable of providing a certain resistance to the door movement itself. 
     Hinges are known in the prior art which comprise friction elements which consist of two shoes mounted on respective linkages articulated to each other, and which are designed to slide on two opposite, facing walls of the box-shaped body of the hinge. 
     This solution, although relatively efficient, is not free of disadvantages. 
     A first disadvantage is due to the complexity of the linkages the shoes are mounted on, which in practical terms, translates as a high cost not only for the components themselves but also for their assembly. 
     Another disadvantage, connected with the position of the shoes, is the risk of the shoes themselves becoming sullied by oily grime or lubricant residues which reduce the friction they apply. 
     Another disadvantage inherent in the prior art hinges with friction system is linked to the impossibility of adjusting the friction action. That means doors that differ in weight even very slightly must be provided with different hinges, which in turn involves considerably high production and storage costs to meet the requirements of doors that can vary significantly in weight, for example when the doors are covered by paneling. In other words, if an electrical household appliance leaves the factory with certain hinges, it is quite possible that the hinges will not be able to guarantee correct door balancing and friction action if the user, for aesthetic purposes, chooses to have the appliance door covered with panels, which may vary considerably in weight depending on the material the panels are made of. 
     SUMMARY OF THE INVENTION 
     The aim of this invention is therefore to provide a hinge for wings or doors which is free of the above mentioned disadvantages. 
     Another aim of the invention is to provide a hinge for doors or wings with improved balancing and friction capabilities. 
     A further aim of the invention is to provide a hinge which can be used with a large number of doors of different weights without having to modify the elastic and/or friction elements for each door. 
     This invention accordingly provides a hinge for doors or wings comprising the features described in any of the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The technical features of the invention according to the aforementioned aims may be easily inferred from the contents of the present description. 
       Further, the advantages of the invention are apparent from the detailed description which follows, with reference to the accompanying drawings, which illustrate a preferred, non-limiting example embodiment of it and in which: 
         FIG. 1  is a schematic perspective view of a first preferred embodiment of a hinge according to this invention; 
         FIG. 2  is a schematic perspective view of the hinge of  FIG. 1  with some parts disassembled; 
         FIG. 3  shows the hinge of  FIG. 2  in a view from a different angle; 
         FIG. 4  is a schematic side elevation view, with some parts transparent in order to better illustrate others, of another embodiment of the hinge of the preceding figures; 
         FIGS. 5 and 6  are schematic perspectives views of the hinge of  FIG. 4  in two different operating configurations; 
         FIG. 7  is a schematic, scaled-up side elevation view, with some parts cut away in order to better illustrate others, of a detail of the hinge of  FIGS. 4 to 6 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIG. 1 , the reference numeral  1  denotes in its entirety a first embodiment of the hinge according to this invention. 
     The hinge, paired with another one, is designed to be mounted, for example on an electrical household appliance, not illustrated, to connect the appliance&#39;s frame to the appliance&#39;s wing or door in such a way that the latter is movable relative to the frame between a closed position and an open position. 
     With reference to  FIGS. 1 to 3 , the hinge  1  comprises a first element  2  adapted for fixing to the aforesaid, not illustrated door of the electrical household appliance, and a second element  3 , of a box-shaped type, adapted for fixing to the aforesaid, not illustrated frame of the electrical household appliance. 
     The first element  2  is pivoted to the second element  3  by a pin  4  to allow reciprocal rotation of the elements  2 ,  3  about a respective axis of rotation A 1 . 
     The axis of rotation A 1  defines the axis of rotation of the aforesaid door, not illustrated, relative to the aforesaid frame, also not illustrated. 
     The first and second elements  2  and  3  are kinematically connected to each other by a connecting lever  5 . 
     At a first end of it  5   a , the connecting lever  5  is pivoted to the first element  2  by a pin  6  in such a way as to rotate at least partly relative to the first element  2  itself about a respective axis A 2 . 
     As illustrated in the drawings, the second, box-shaped element  3  extends longitudinally along a respective axis B which is also the principal direction of extension of the second element  3 . 
     The hinge  1  also comprises a helical spring  7  and a drive rod  8  of the spring  7 , both supported by the second, box-shaped element  3 . 
     The drive rod  8  is hooked at the bottom of it to the lever  5  at a second end of it  5   b , opposite the first end  5   a.    
     The drive rod  8  of the spring  7  is advantageously positioned inside the spring  7  itself and is connected to the top thereof, for example by a stop element F in such a way as to compress it, as described in more detail below. 
     In other words, the drive rod  8  has an upper end that is longitudinally opposite the end that is hooked to the lever  5 , the upper end being designed to engage an upper end coil of the spring  7  in such a way as to compress the spring  7 . 
     The spring  7  and the rod  8  extend principally along the aforesaid axis of extension B of the second element  3 . 
     The spring  7  constitutes respective elastic means for the hinge  1 . 
     The second, box-shaped element  3  has a set of perimeter walls, including an upper wall  3   a  and two side walls  3   b ,  3   c , respectively front and rear. 
     On the upper perimeter wall  3   a , is formed a hole  9  for the passage of the drive rod  8 . 
     At the hole  9 , and coaxial with it, there is a hollow cylinder  10  for housing a tapered friction element  11 . 
     The friction element  11 , better visible in  FIG. 2  where it is illustrated outside the cylinder  10  that normally houses it during operation of the hinge  1 , comprises a tapered bottom portion  11   a , a central collar  11   b  and a cylindrical upper portion  11   c.    
     The tapered bottom portion  11   a  is divided into two lateral fingernail-shaped protrusions  12 ,  13  adapted to superficially engage, and apply a frictional action on, the two opposite faces  8   a ,  8   b  of the rod  8 . 
     The collar  11   b  is adapted, at the bottom of it, to come into abutment with the cylinder  10  and, at the top of it, to constitute a stop for the lower end coil of the spring  7 . 
     The upper portion  11   c  is also divided into two parts  14 ,  15 , each designed to face a respective face  8   a ,  8   b  of the drive rod  8 . 
     With reference in particular to  FIGS. 1 and 2 , the hinge  1  comprises a roller  16 , operatively interposed between the lever  5  and the second, box-shaped element  3 , supported by the lever  5  itself, and adapted to rollably engage with a front side wall  3   b  of the second, box-shaped element  3 . 
     The roller  16  has a respective axis of rotation A 3 , integral with the lever  5 . 
     Advantageously, but not necessarily, the roller  16  is composed of two circular portions joined by a central hub. 
     During rotation, the central hub is held within a semicircular cavity  5   a  formed on the lever  5 . 
     The embodiment of the hinge  1  illustrated in  FIGS. 4 to 7  is labeled  1 ′ and basically differs from the hinge described above with reference to  FIGS. 1 to 3 , solely in that the second, box-shaped element  3  has a projection  30  at the top of the upper wall  3   a.    
     The projection  30 , also box-shaped, houses inside it an adjustable friction element  31 . 
     The adjustable friction element  31  comprises a first and a second plug  32 ,  33  made of a material with a high friction coefficient, located in such a way that each engages a respective face  8   a ,  8   b  of the drive rod  8 . 
     The second plug  33  is advantageously fixed. 
     The element  31  also comprises a plate  34  fixed at longitudinal ends of it to the projection  30 , and an adjustment screw  35  designed to be screwably engaged in a respective threaded hole formed on the plate  34 . 
     In other embodiments, which are not illustrated, the plate  34  may be substituted with threading for engaging the screw  35  formed in the structure of the projection  30  itself. 
     The adjustment screw  35  constitutes for the hinge  1 ′, means for modifying the position of the first plug  32  relative to the drive rod  8 . 
     In use, screwing in the screw  35  pushes the first plug  32  against the face  8   a  of the rod  8 , thereby increasing the frictional force which opposes the sliding of the two parts relative to each other. That in turn increases the frictional action opposing the opening/closing movement of the hinge  1 ′. Unscrewing the screw  35 , on the other hand, reduces the frictional force and, hence, reduces the frictional action opposing the opening/closing movement of the hinge  1 ′. 
     As illustrated in  FIG. 5 , the adjustment screw  35  is accessible from the outside of the second, box shaped element  3  so it can be easily screwed and unscrewed even after installation on the respective electrical household appliance. In other words, the screw  35 , once the hinge  1 ′ has been installed on an electrical household appliance, remains accessible to allow the frictional action to be adjusted even when the electrical household appliance itself is fully assembled, for example after it has been used for a certain period or after a covering panel has been fitted to the door of the finished appliance. 
     With reference to both the embodiments  1  and  1 ′ of the hinge according to the invention, the aforesaid tapered friction element  11  and adjustable friction element  31  constitute, for the hinges  1 ,  1 ′, friction means adapted to operate on the rod  8  to slow its sliding relative to the second, box-shaped element  3 . 
     Again with reference to both the embodiments  1  and  1 ′ of the hinge according to the invention, the roller  16  constitutes, for the hinges  1 ,  1 ′, guide means for guiding the movement of the drive rod  8  along the direction of its axis of longitudinal extension. 
     More in detail,  FIGS. 4 to 6  show in sequence different operating configurations of the hinge  1 ′, namely, a closed configuration in  FIG. 4 , a half open configuration in  FIG. 5  and a substantially open position in  FIG. 6 . 
     During the passage from the closed configuration of  FIG. 4  to the open configuration of  FIG. 6 , the spring  7  is compressed and loaded as a result of the pulling action applied by the rod  8  which is in turn pulled by the lever  5 . In effect, the lever  5  applies a pulling action as a result of the rotation of the first element  2  relative to the second, box-shaped element  3  about the axis A 1 . The lever  5 , in pulling the rod  8 , slides inside and relative to the second, box-shaped element  3 . 
     During its movement relative to the second, box-shaped element  3 , the upper end  5   b  of the lever  5  remains substantially equidistant from the wall  3   b  of the second element  3 ; that guarantees that during its sliding relative to the second, box-shaped element  3 , the drive rod  8  remains parallel to itself and is translated along the direction B. 
     The fact that the rod  8  is translated along the direction B, that is to say, without making an angle with that direction, means that the frictional action applied to it by the friction means is constant and regular. 
     In other words, thanks to the presence of the roller  16 , the rod  8  remains with its faces  8   a ,  8   b  parallel to the friction surfaces of the friction means, thereby guaranteeing a regular frictional action without jamming. Jamming might also occur if the rod  8  moved at an angle in such a way as, for example, to strike one of the fingernail-shaped protrusions  12 ,  13  on the element  11 . 
     With reference to what has already been stated above in connection with the adjustable friction element  31 , attention is again drawn to the fact that the two plugs  32 ,  33  operate on respective faces  8   a ,  8   b  of the drive rod  8  of spring  7 , the plug  33  being fixed, while the plug  32  is adjustable and able to be translated longitudinally, that is to say, towards/away from the rod  8  using the adjustment screw  35 . 
     Basically, the screw  35 , by being screwed or unscrewed, modifies the position of the plug  32 . The latter thus modifies the contact force it exerts on the drive rod  8 , thereby modifying the amount of frictional action it applies to the rod  8 . 
     Experimental tests have shown that even the smallest variations in turning the screw  35 , and hence in positioning the plug  32 , cause appreciable changes to the frictional action on the drive rod  8  of the spring  7 . 
     The advantage is that the frictional action on the hinge can be easily and effectively modified, even according to the weight of the door the hinge is mounted on, by a simple adjustment using a screw which is located on the edge of the side wall of the electrical household appliance and which is therefore easy to access. 
     As pointed out above, another essential aspect of this invention is the presence of the roller  16  which is supported by the lever  5  and which advantageously allows the drive rod  8  to be held in a straight line, keeping it on the same axis so as not to upset the setting of the frictional action to be applied. Thus, since both sides of the rod  8  are operated on by the friction means, it is very important to keep the rod on the same axis as it moves. 
     If it were to move out of axis, its frictional action would easily be altered: in effect, the friction applied to one face of the rod  8  would increase and that on the other face would decrease. 
     In this regard, the roller  16  rolls on the side wall  3   b  of the box-shaped element  3  so as to keep the linkage point on the drive rod  8  at a constant distance from side wall  3   b  itself. Otherwise, when opened, the hinge would cause the drive rod  8  to move closer to the wall  3   b  because the force applied by the lever  5  would also have a component perpendicular to the side wall  3   b  of the second, box-shaped element  3 . The roller  16  advantageously allows this component of the force to be compensated by causing the pulling action of the lever  5  on the drive rod  8  to remain parallel to the axis of the rod  8 . 
     The invention described above is susceptible of industrial application and may be modified and adapted in several ways without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements.