DOOR HINGE

Abstract

A hinge for dishwasher doors, comprising a first element (2) and a second element (3) which are pivotably connected to each other and tiltable relative to each other, wherein one can be attached to a frame and the other to a door of an electrical appliance in order to make the door movable relative to the frame between a closed and an open position, a lever (5) which connects the first and the second element (2, 3), an elastic element (7) which is connected to the lever (5) and which can generate an elastic reaction force by its own deformation which can at least partially compensate for the weight of the door when opening or closing, and means for regulating the intensity of this elastic reaction force.

Description

The present invention relates to a door hinge.More particularly, the present invention relates to a hinge for dishwasher doors, also intended to support additional lining elements such as panels or the like.By way of non-limiting example, the present invention will be described with reference to a front opening dishwasher.The hinges used for the doors of dishwashers usually consist of two elements kinematically connected to each other and moving in a mutually folding manner, a first of these elements being fixed to the door and a second to the frame of the dishwasher.Between the first and second elements there is normally a lever on which elastic elements act to dynamically influence the opening / closing of the door.The main function of the elastic elements acting on the lever is to counteract the weight of the door and to achieve a substantial balancing of the door, so that it remains stably open at any angle and above all is prevented from falling down by its own weight after opening. In recent years, automatic dishwasher door opening devices have been developed to facilitate the drying of the tableware after the rinsing phase.Also, due to the high temperatures of the wash water used during normal wash cycles, opening the door at a certain time at the end of the wash cycle allows the water vapor to escape and prevents it from condensing on the tableware during cooling.There are many different ways of opening the doors, and most commonly include those with a motorized drive which opens the door slightly a few degrees, usually less than 10° sexagemimal, at the end of the washing cycle to allow the vapour to escape.This solution is certainly effective, but also very expensive, since it requires a special drive and the necessary mechanical connections to the door.Other solutions include a snap-in opening of the door, which is advantageously achieved by the compression of a spring element when the door is closed.In this case, it is not easy to regulate the pressure required to achieve the desired opening of the door, which is usually bound to balanced hinges. Moreover, the movement of the door as a result of the pressure of the snap-action device can also depend on the weight of the cover plate resting on the door, wherein this weight is very different depending on the furniture item in which the dishwasher is installed.These solutions therefore have the drawback that they do not guarantee the desired degree of opening of the door.It is therefore an object of the present invention to provide a door hinge which overcomes the disadvantages of the known technique and which is both simple and cost-effective to produce and convenient to use.A further object of the present invention is to provide a structurally simple door hinge.According to the invention, these and other objects are achieved by a door hinge having the technical features described in the appended claims.The technical features of the invention according to the aforementioned objects are clearly described in the appended claims, and their advantages will become apparent from the following detailed description with reference to the accompanying drawings which show an exemplary and non-limiting embodiment, in whichFIG. 1 is a schematic perspective view of a door hinge according to the present invention in a partially opened position;FIG. 2 is an exploded perspective view of the hinge of FIG. 1 ;FIGS. 3, 4, 5 to 6 show schematic side views of the hinge from FIG. 1 in its four different use arrangements;FIGS. 7, 8, 9 to 10 show the same views as in FIGS. 3, 4, 5 to 6, a part of which has been removed in order to better emphasize other parts;FIGS. 11 and 12 show schematic perspective views from different perspectives of a detail of the hinge described in the preceding figures;FIGS. 13 and 14 show schematic perspective views from different angles of the hinge shown in the preceding FIGS. 1, 2, 3, 4, 5 to 6, respectively;FIG. 15 shows a top view from below of the detail designated in FIGS. 13 and 14.As shown in FIG. 1, an embodiment of a door hinge according to the present invention is designated by reference numeral 1.The hinge 1 is intended to be mounted in pairs on a dishwasher in order to connect its frame (not shown) to a door, so that the latter is tiltable with respect to the frame itself, and in other words, the hinge is intended to make the door movable on a flap with respect to the frame between a closed and an open position and vice versa.As can be seen from the figures attached, the hinge 1 consists of a first element 2 which can be fixed to the aforementioned and not shown door of the dishwasher and a second element 3 which is box-shaped and is fixed to the aforementioned and not shown frame of the dishwasher.The first element 2 is screwed onto the second element 3 by means of a bolt 4 to allow the mutual rotation of the first and second elements 2, 3 themselves about a respective axis of rotation A 1.The axis of rotation A1 defines the axis of rotation of said and not shown door with respect to said and not shown frame.The above-mentioned first and second elements 2, 3 are kinematically connected to each other via a connecting lever 5.At its own first lower end 5a, the connecting lever 5 is supported on the first element 2 by means of a pin 6, so that it can rotate at least partially with respect to the first element 2 itself about a corresponding axis A2.The hinge 1 further comprises a coil spring 7 and a control rod 8 for controlling the spring 7 itself, both supported by the second box member 3.The control rod 8 is connected at the bottom side with a hook 9.The hook 9 is attached to a second end 5 bof the lever 5 that is opposite to the first end 5 a.The control rod 8 controlling the spring 7 is advantageously arranged inside the spring 7 itself and connected to it at the top in a known manner, in order to actuate its compression in a also substantially known manner.In other words, as shown in Fig. 2, the control rod 8a has an upper end 8a longitudinally opposite to that engaged with the lever 5, the upper end 8a being adapted to engage with an upper end turn of the spring 7 to compress the spring 7 itself.The spring 7 and the rod 8 develop according to a direction B of the prevailing development of the second box element 3.The spring 7 defines for the hinge 1 a corresponding elastic element capable of generating, by its own deformation, an elastic reaction force capable of at least partially compensating the weight force of the door during opening or closing.On the connecting lever 5 there is a slot 10, which slot 10 is elongated and has its own inner peripheral opposite edges 10a, 10b suitable for smoothly engaging a guide pin 11 firmly connected to the second element 3 by means of a rivet 12.Specifically, the guide pin 11 is rotatably connected to the second box-shaped member 3 and oscillates about its central axis A 3.According to variants not shown, but falling under the same inventive concept, the guide pin is mounted on the lever and the slot is located on the second element 3.With particular reference to Figs. 11 and 12, at a lower end of the slit 10, a groove 13 defining a bend in the development of the peripheral edge 10a itself is obtained at the peripheral edge 10a.In other words, the peripheral edge 10a of the slit 10 has a change in the convexity in the vicinity of the aforementioned groove 13.In other words, the aforementioned groove 13 presents a recess in the peripheral edge 10a which, as will be described in more detail below, serves to define, at least under certain circumstances, a stable equilibrium position for the guide pin 11 as it moves relative to the slot 10.As shown in detail in Figures 13, 14 to 15, the guide pin 11 comprises a central body 11a and a head 11b which rests on and extends radially with respect to the central body 11a, as will be explained in more detail below.The head 11 bhas an approximately polygonal shape with straight circumferential sides connected to each other by rounded edges.The concept just described means that the head 11 bextends on a plane perpendicular to the central axis A 3 of the pin 11 outside the cylinder in which the central body 11 ais inscribed.The central body 11a has two flat surfaces SP which are parallel to each other and to the central axis A3 of the pivot pin 11.As shown in Figs. 14 and 15, the aforesaid flat surfaces SP of the central body 11a are also symmetrically arranged on opposite bands of the central axis A3 of the pin 11, each of the flat surfaces SP being adapted to slide along a corresponding peripheral edge 10a, 10b of the slot 10.With further reference to Figures 14 and 15, the central body 11a of the pin 11 has two cylindrical surfaces SC connecting the two aforementioned parallel flat surfaces SP.For the purposes of this discussion, the term "cylindrical surfaces" refers to two portions of the outer surface of a cylinder, these portions being arranged diametrically opposite each other and identified from a cylinder section having two planes parallel to each other and to the axis of the cylinder and arranged on opposite sides of the axis of the cylinder itself, which coincides with the axis A3 of the pin 11, and being placed at a distance from this axis which is smaller than the radius of the cylinder.As shown in FIGS. 11 and 12, the hinge 1 has a pin 14 protruding from the connecting lever 5 in the vicinity of the aforementioned groove 13.As will be described in more detail below, the pin 14 is designed to engage the above-mentioned head 11 bof the guide bolt 11 in order to cause at least partial rotation of the bolt 11 itself about its central axis A 3.Advantageously, the connecting lever 5 is made of pressed sheet metal and the pin 14 is produced by punching, i.e. by punching with a small punch.The hinges 1 illustrated and described here are intended to be mounted in pairs on a device, for example a dishwasher, with a movable flap at the side ends of this door.FIGS. 3 and 7 show the hinge 1 in the closed position, which corresponds to a closed position of the door (not shown) of the dishwasher.In use, as also shown in the enlarged scale circle of Figure 7, the opening movement of the dishwasher door and thus of the first element 2 of the hinge 1 connected thereto, starting from the closed configuration of Figure 7, engages the lever 5 in contact with the central body 11a of the guide pin 11 and causes a partial rotation thereof about its own central axis A3 (counterclockwise with respect to Figures 1, 2, 3, 4, 5, 6, 7, 8, 9 to 10) until it is brought into the configuration shown in Figures 4 and 8 in correspondence with an opening angle of about 8° sexageimal of the door.As clearly seen in Figure 8, the body 11a is arranged in the middle of the pin 11 so that part of its own cylindrical surface SC substantially abuts the groove 13 of the slot 10. In other words, a part of the cylindrical connecting surface SC of the pin 11 is arranged adjacent to the aforementioned groove 13 of the slot 10, the groove 13 being opposite with respect to this cylindrical surface SC.Advantageously, the radii of curvature of the groove 13 and of the cylindrical connecting surface SC are very similar or even substantially the same.The engagement of the guide pin 11 or a cylindrical surface SC thereof in the groove 13 of the slot 10 causes a kind of jamming in the opening movement of the hinge, and in order to overcome this jamming an additional force is required, for example by a user. In other words, in conjunction with the spring action, a stable equilibrium position for the hinge 1 is determined, which can only be left by applying a specific force.Substantially, this property of the hinge 1 is used to create a half-open condition of the dishwasher door to allow the steam to escape at the end of the rinsing and drying phase. Advantageously, the dishwasher door (not shown) is released from a closing member, for example by an electrical control, and is pressed open, even if only by the action of a prestressed elastic element.The presence of the groove 13, in conjunction with the guide pin 11 shaped according to the invention, and an effective adjustment of the opening force, have the effect that the hinge stops at a certain opening angle, for example by the value 8° sexageimal, as shown in Figures 3 and 7, in order to let the steam present inside the dishwasher escape accurately.Starting from this state of stable half-opening, in order to continue with a larger opening of the door, the intervention of the user is required, overcoming with a reduced force the equilibrium state determined by the accommodation of the pin 11 in the groove 13.Figures 5 and 6 show the successive phases of opening of the hinge 1 and of the door (not shown).The above described equilibrium condition, which corresponds approximately to the value 8° sexegrally to the opening, should be aimed at during the opening phase of the door, as otherwise it might lead to certain inconveniences representing an undesirable obstacle during the closing phase.To solve this problem, the pin 14 has been developed, which, by engaging with the head 11b of the guide pin 11 during the closing phase, when the above-described equilibrium position is exceeded, determines a rotation (clockwise with respect to the accompanying figures) of the pin 11 itself, so as to allow it to overcome the equilibrium position determined by the groove 13 without jamming.In other words, as clearly shown in the relatively enlarged circles in Figures 8 and 7, during the closing phase, starting from the position shown in Figure 8 in which the central body 11a of the pin 11 is substantially housed in the groove 13, the engagement of the head 11b of the pin 11 with the pin 14 (engagement shown in Figures 4 and 3 in which the head 11b is visible) causes the central body 11a connected to it to perform a partial rotation (counterclockwise with respect to the figures shown), thus causing a kind of rolling of one of its cylindrical surfaces SC on the lower edge of the groove 14 itself.This type of rolling, clearly shown in the enlarged circle in Figure 7, prevents the pin 11 from jamming in the groove 14, which is aimed for for the above reasons during the opening phase of the flap and which, if it remained in the closing phase, would create an undesirable discontinuity in the closing movement of the flap.The door hinge 1 according to the invention achieves the intended purposes and achieves important advantages.A first advantage is that with the door hinge 1 according to the invention a stable half-open state of the dishwasher door can be achieved in an advantageous manner without complicated and expensive solutions having to be introduced.A further advantage lies in the possibility of easily overcoming such a stable position when closing the door in order to achieve a substantially smooth movement.

Claims

Hinge for doors of dishwashers, comprising: - a first element (2) and a second element (3) which engage and can be moved back and forth by a flap, the first and second elements (2, 3) being able to be fixed one to a frame and the other to a door of a dishwasher in order to make the door movable with respect to the frame between a closed and an open position, - a lever (5) connecting the first and second elements (2, 3), the lever (5) being provided with a slot (10), - an elastic element (7) connected to the lever (5) and able to generate, by its own deformation, an elastic reaction force capable of at least partially compensating the weight force of the door during its opening or closing, a guide pin (11) of the lever (5) carried by one of the first (2) and second (3) elements, the guide pin (11) slidably engaging the slot (10), characterized in that the guide pin (11) oscillates about a corresponding central axis (A3) and comprises a central body (11a) having at least one planar surface (SP) parallel to the axis (A3), the planar surface (SP) being slidable along an edge (10a, 10b) of the slot (10), and in that the slot (10) has a groove (13) for stably receiving the central body (11a) of the guide pin (11), which groove is configured to define an equilibrium position of the door between its closed and its open positions.Hinge according to claim 1, characterised in that the central body (11a) of the guide pin (11) has two flat surfaces (SP) parallel to the central axis (A3), symmetrically arranged on opposite bands of the central axis (A3), each of the flat surfaces (SP) being suitable to slide along a corresponding edge (10a, 10b) of the slot (10).Hinge according to claim 2, characterised in that the central pin body (11a) comprises two cylindrical surfaces (SC) connecting the two parallel planar surfaces (SP).Hinge according to claim 3, characterised in that the groove (13) has, at least in one portion, a radius of curvature which substantially corresponds to the radius of curvature of the cylindrical surfaces (SC).Hinge according to any one of the preceding claims, characterized in that the guide pin (11) has a head (11b) projecting radially from the central body (11a).Hinge according to claim 5, characterised in that the radially protruding head (11b) has an at least approximately polygonal shape.Hinge according to claim 6, characterized in that it comprises a pin (14) protruding from the connecting lever (5), said pin (14) being configured to engage with the head (11b) of the guide pin (11) to cause an at least partial rotation of the guide pin (11) about its central axis (A3).Hinge according to claim 7, wherein the connecting lever (5) is made of pressed sheet metal, characterised in that the pin (14) is produced by punching.Dishwasher with a door for opening a flap, characterised in that it comprises a pair of hinges (1) according to one of the preceding claims.

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