Device for hinging a door, in particular a dishwasher door, to a fixed structure

Abstract: A device for hinging to a fixed structure (2) a door (3) of an appliance, in particular a dishwasher, in which the door (3) is mounted so it can swivel around a fixed horizontal axis (5), and is subjected to the action of an elastic element (6) returning the door (3) to the closed position, comprising: a leverage (7) operating between the door (3) and the elastic element (6), and provided with a kinematic chain (7a) having rods (10, 9, 8) reciprocally articulated and arranged in succession; the first (10) and the last rod (8) of the kinematic chain (7a) being connected respectively to the door (3) and to the elastic element (6) and being able to rotate around fixed axes (5, 11) of the structure (2); the first rod (10) of the kinematic chain (7a) being provided with articulated joints (10a, 10b) placed at a reciprocal distance smaller than the distance between corresponding joints (8a, 8b) at the end of the last rod (8); said last rod (8) hinging with the elastic element (6) on a pivot (13a) located at a distance from the main axis (11) of the last rod (8) not exceeding the distance between the joints (10a, 10b) of the first rod (10).

Description: The present invention relates to an appliance, in particular a dishwasher, comprising a fixed structure, a door and a device for hinging the door to the fixed structure. In the field of appliances, a widespread use is made of doors mounted on a vertical wall of the appliance and swivelling around a fixed horizontal axis between the extreme positions of shutting off the interior compartment of the appliance and of allowing free access to said compartment. Doors of the aforesaid type are subjected to the action of an elastic element set in such a way as to constantly return the door towards the position where it shuts off the compartment. Since the weight of the door takes on varying arms with respect to the fixed axis of rotation as the door is opened and closed, the elastic elements and, more in general, the hinging devices comprising them, require particular structures to determine returning actions varying with laws correlated to the laws governing the variation of the actions induced by the weight force. It is also known from document EP 0551234, an appliance comprising a casing with an access door articulated on an horizontal axis and a device for counterbalancing the weight of the door in at least one partly opened position. Said device comprises a spring fixed at its first end to the casing, and a leverage operationally active between the spring and the door. The leverage comprises a kinematic chain and a connection rod. The kinematic chain has three rods reciprocally articulated and arranged in succession. The first and the third doors are mounted on the casing in such a way as to swivel around fixes axes. In addition the first rod is embedded into the door while the third is connected to the elastic element by the connecting rod. The leverage is arranged in such a way that the return action of the device decreases when the opening angle of the door increases. Document EP 0692590 shows a device that is felt to be the closest prior art to the present invention. Said device has substantially the same structure of that of doc. EP 0551234 but exerts a return action that increases when the opening angle of the door increases. The device of this document has also a system for adjusting the intensity of the return action by modifying the pre-load of the spring. In the particular case of the embedded dishwasher, the doors' own weight is far greater than that of similar doors fitted to other appliances such as kitchen ovens. This added weight derives from the fact that, in addition to supporting the devices providing watertightness, the panel also supports the dishwasher's command, control and adjustment circuitry and, most importantly, it supports the panels which integrate the dishwasher aesthetically with the furniture it is embedded in. The weight, which is much greater than that of appliances with similar opening actions, implies structuring and dimensioning the hinging devices in a way that is wholly specific to the dishwasher sector. Within the context of this general set of problems, a specific problem is represented by the wide variability of the weights of the panels fastened to the door. Since the weights of the panels vary within a set of values ranging indicatively from 3 to 10 da N, known hinging devices are quite differentiated both in terms of the physical structure of their component parts, and in terms of their capability to be used properly with heavier or lighter panels. This state of affairs entails a series of drawbacks represented by the need to manufacture and manage quite a large number of different types of hinging devices, with obvious negative economic consequences, The purpose of the present invention therefore is to eliminate the aforementioned drawbacks by means of an appliance with a hinging device of the kind indicated in the preamble to claim 1, and such as to be usable indifferently on the doors of all types of dishwashers and regardless of the weight of the equipment contained within the door and/or of the weight of the panels supported externally. According to the invention, this purpose is reached by means of an appliance as described in the appended claims. The fundamental advantage of the invention is represented by the fact that it allows the availability of a single standard solution which, thanks to its universal application nature, simplifies manufacturing processes and provides for strong economic benefits. The technical characteristics of the invention, according to the aforesaid purposes, can clearly be noted from the content of the claims reported below and its advantages will be further clarified in the detailed description which follows, made with reference to the enclosed drawings, which represent an embodiment provided purely by way of non limiting example, in which: Figure 1 is a raised view of an appliance according to the invention, depicted in a position corresponding to the closed position of the door of an appliance; Figure 2 is a raised view of the appliance as per the previous Figure 1, depicted in a position corresponding to the totally opened condition of the appliance door; Figure 3 is a top plan view of the appliance depicted in Figure 2; Figures 4 and 5 are respectively raised view of a variation to the embodiment of the appliance according to the invention, depicted in the conditions corresponding to the fully opened and fully closed positions of the door. With reference to the accompanying drawings, 1 is the label indicating in its entirety an appliance, in particular a dishwasher, comprising a fixed structure 2, a door 3 and a device for hinging the door to the fixed structure 2. Fixed structure 2 is represented in the Figures by a metal plate which is made integral with the casing of the dishwasher. Door 3 is mounted on a vertical wall, not represented, of the casing, it can swivel around a fixed horizontal axis 5, borne by the structure 2 in correspondence with the lower horizontal side of the door 3, and it is interconnected with an elastic element 6 structured in such a way as to contrast the opening motion of the door 3 from the vertical position in Figure 1 to the horizontal position in Figure 2. The elastic element 6 preferably comprises a helical compression spring, mounted on the fixed structure 2 in such a way as to yield along an essentially vertical line 14. Between the door 3 and the elastic element 6 a leverage 7 is operationally placed, whose purpose is to correlate proportionately, and as a function of the opening angle (alpha) of the door 3, the intensity of the return action of the spring with the moment of rotation of the door 3 generated by the latter's own weight. The leverage 7 comprises more in particular a kinematic chain 7a with reciprocally articulated rods 10, 9, 8, arranged in succession. Rods 10, 8 at the ends of the kinematic chain 7a are interconnected with the fixed structure 2 by means of hinges which allow the angular oscillation of rods 10, 8 around fixed axes 5, 11. The first rod 10 is integral with the door 3 in whose structure it is directly integrated. The last rod 8 instead is connected to a rod 21 guiding and compressing the spring 6, by means of a connecting rod 20 interposed and fitted with ends articulated on pivots 13a and 13b. An observation of Figures 1 and 2 shows in particular that the kinematic chain 7a preferably presents a proportioning in the length of the respective rods 10, 9, 8 and a distance between the fixed axes 5, 11 suited to define an articulated quadrilateral. In this case, the end rods 10, 8 function as rocking levers connected to each other by an intermediate connecting rod 9 and oscillating on the fixed structure 2. Furthermore, observing in particular Figure 1, it can be seen that the first rod 10 of the kinematic chain 7a presents articulated joints 10a, 10b for connection with intermediate connecting the rod 9 and with the fixed structure 2, which joints are located at a reciprocal distance smaller than the distance between the corresponding articulated joints 8a, 8b connecting the last rod 8 to the intermediate connecting rod 9 and to the fixed structure 2. Moreover, in regard to the location of the pivot 13a with respect to the last rod 8, from Figures 1 and 2 it can be noted that the pivot 13a itself is located at a distance from the fixed axis 11 of the last rod 8 which does not exceed the distance between the articulated joints 10a and 10b of the first rod 10. The pivot 13a furthermore is preferably displaced laterally with respect to the straight line 15 ideally connecting the end joints 8a and 8b of the last rod 8. This lateral displacement is performed preferably by the same part of the door 3 in such a way as to cause, during the use of the device 1, the door 3 to close without striking the structure 2 of the dishwasher casing. Referring to Figures 1 and 2, it can also be noted that in a preferable embodiment the articulated quadrilateral presents, when the door 3 is in the closed condition, an angle B measuring substantially 80° between the first rod 10 and a straight line 50 passing through the fixed axes 5 and 11; an angle G measuring substantially 80° between the last rod 8 and the straight line 50; an angle D measuring substantially 80° between the last rod 8 and the intermediate rod 9; an angle T measuring substantially 120° between the intermediate connecting rod 9 and the first rod 10; an angle F measuring substantially 70° between the line 50 passing through the fixed axes 5 and 11 and the straight line 51 passing through the articulation axis 11 of the last rod 8 and the pivot 13a articulating the elastic element 6. The articulated quadrilateral assumes for said angles, when the door 3 is in the open configuration, values measuring substantially 170° for angle B, 10° for angle G, 160° for angle D, 20° for angle T and 0° for angle F. An alternative embodiment of device 1, illustrated in Figures 4 and 5, also entails the provision of means 16, 17 for adjusting the displacement of the pivot 13 with respect to the straight line 15 passing through the joints 8a, 8b. These means, more in particular, comprise a slot 16 which is developed along a circumference arc which is obtained on the last rod 8 and which houses the pivot 13a that connects, with the last rod 8, the connecting rod 20 of the elastic element 6. An adjusting screw 17 is operationally placed between the slot 16 and the pivot 13a to vary the position of the pivot 13a with respect to the slot 16 and thus with respect to the aforesaid straight line 15. Hinging device 1 designed according to the invention, in use, reveals a global elastic reaction which is quite insensitive to external load variations even when induced by strong variations in the weight of the door 3. As a consequence, the device is suited to be applied practically to all known models of embedded dishwashers, whatever the type of lining panel adopted. Moreover, the device 1 can also be manufactured in a single body thus allowing for quick and easy mounting on the casing of the appliance it is destined for. The invention thus conceived can be subjected to numerous modifications and variations, all falling within the scope of the inventive concept. Moreover, all components may be replaced with technically equivalent parts.

Claims: Appliance, in particular a dishwasher, comprising a fixed structure (2), a door (3) and a device for hinging the door to the fixed structure (2) the door (3) being mounted so as to swivel around a fixed horizontal axis (5) and being subjected to the action of an elastic element (6) returning it to the closed position, said device comprising a leverage (7) which is operationally placed between the door (3) and the elastic element (6), and is provided with a kinematic chain (7a), a connecting rod (20) and a guiding rod (21), the kinematic chain (7a) having rods (10, 9, 8) reciprocally articulated and arranged in succession, the first (10) rod (10) of the kinematic chain (7a) being connected respectively to the door (3) the last rod (8) of the kinematic claim (7a) being connetted by the connecting rod (20) to the guiding rod (21), said guiding rod guiding and compressing the elastic element (6), said first and least rod (10,11) being mounted on the fixed structure (2) in such a way as to swivel around fixed axes (5, 11), the first rod (10) of the kinematic chain (7a) being provided with articulated joints (10a, 10b), said last rod (8) hinging with the connecting rod (20) on a pivot (13a) characterized in that said pivot located at a distance from the fixed axis (11) of the last rod (8) not exceeding the distance between the articulated joints (10a, 10b) of the first rod (10), and in that the articulated points (10a, 10b) of the first rod (10) are located at a reciprocal distance which is smaller than the distance between the corresponding articulated joints at the end of the last rod (8). Appliance, according to claim 1, characterised in that said elastic element (6) yields along an essentially vertical line of action (14) Appliance, according to claim 2, characterised in that the elastic element (6) is actuated by a compression spring. Appliance, according to claim 1. characterised in that the kinematic chain (7a) is fastened to the fixed axes (5, 11) of the structure (2) and comprises rods (10, 9, 8) of lengths suited to define an articulated quadrilateral mechanism with two rocking levers (10, 8) which oscillate with respect to the structure (2), are connected by an intermediate connecting rod (9) and are fixed to the door (3) and to the elastic element (6). Appliance, according to claim 1, characterised in that the pivot (13a) providing reciprocal connection between the elastic element (6) and the last rod (8) is displaced laterally with respect to a straight line (15) passing through the end articulated joints (8a, 8b) of the last rod (8). Appliance, according to claim 4, characterised in that said pivot (13a) is displaced with respect to the straight line (15) to the same side as the door (3). Appliance, according to claim 1, characterised in that it includes means to adjust the displacement of the pivot (13a) with respect to the straight line (15) passing through the end articulated joints (8a, 8b) of the last rod (8). Appliance, according to claim 4, characterised in that said adjustment means comprise a slot (16) obtained in the last rod (8) in which is engaged the pivot (13a) connecting the elastic element (6), and an adjusting screw (17) operationally placed between the slot (16) and the pivot (13a) to vary the position of the pivot (13a) with respect to said straight line (15). Appliance, according to any of the previous claims, characterised in that it is constructed in a single body. Appliance according to claim 4, characterised in that the articulated quadrilateral presents, when the door (3) is in the closed position, an angle (B) measuring substantially 80° between the first rod (10) and a straight line (50) passing through the fixed axes (5, 11), an angle (G) measuring substantially 80° between the last rod (8) and said straight line (50); an angle D measuring substantially 80° between the last rod (8) and the intermediate connecting rod (9); an angle (T) measuring substantially 120° between the intermediate rod (9) and the first rod (10); an angle (F) measuring substantially 70° between said straight line (50) passing through the fixed axes (5, 11) and a straight line (51) passing through the axis of articulation (11) of the last rod (8) and the pivot (13a) of articulation of the elastic element (6); said articulated quadrilateral assuming for said angles, when the door (3) is in the open condition, values measuring substantially 170° for angle (B), 10° for angle (G), 160° for angle (D), 20° for angle (T) and 0° for angle (F).

Inventors: VANINI ANGELO, ZANETTI AUGUSTO, VANINI, ANGELO, ZANETTI, AUGUSTO
Applicants: NUOVA STAR S P A, NUOVA STAR S.P.A.
Application year: 1997
Main classification: A47L15
IPC codes: A47L15