Hinge for doors

A hinge for doors, in particular for electrical appliances, comprises a box-shaped body (3), a lever (4) pivoting at the box-shaped body (3) at a respective axis (A) of rotation so that the body (3) and the lever (4) can move relative to each other by tilting, the box-shaped body (3), a spring (12) housed in the box-shaped body (3) and designed to operate in conjunction with a first portion (4a) of the lever (4) to adjust the motion of the lever (4) and the box-shaped body (3) relative to each other.

BACKGROUND OF THE INVENTION

The present invention relates to a hinge for doors.

The use of a hinge made in accordance with this invention is particularly advantageous for connecting the door of an electrical appliance which opens at the top to the respective supporting frame, in particular in the case of a washing machine to which express reference is made below, without thereby limiting the scope of the invention.

In top loading washing machines the hinges normally consist of two separate elements, usually at least one having a box-shaped structure, the two elements being kinematically connected to each other.

More precisely, one element is usually fixed to the washing machine supporting frame, at one side of the opening used for loading and unloading, whilst the other element is fixed to one edge of the door, which in this way is rendered movable so that it can tilt relative to the opening.

One of the two elements usually consists of an arm of a rocker lever, pivoting at the other element.

Means for adjusting door opening usually act on the second arm of said lever. Said means may comprise elastic elements and friction elements able to facilitate and/or oppose the door opening-closing movement.

Basically, the function of said means is both to provide an elastic force able to help the user with the effort of lifting the door, and to balance the door, applying a braking action to it, so that dangerous high speeds are not reached during opening or closing.

In current top loading washing machines, there is a need to apply a braking action, that is to say, to balance, the door for most of its opening/closing angle but, as the door is closed, the presence of an electromechanical switch requires significant force to operate it. Until now the two requirements were not satisfied simultaneously: there are hinges which are very balanced, which therefore oblige the user to apply a high level of prolonged force to open/close the door and to activate/deactivate the switch, or hinges which, providing a slight balancing action cause the closing door to acquire a level of motion high enough to activate the switch, therefore with all of the risks linked to a door which gains speed when closing and which can even strike the user. Such a circumstance is a disadvantage of prior art hinges.

SUMMARY OF THE INVENTION

The present invention has for an aim to provide a hinge for wings or doors which is free of the disadvantage described above and which at the same time has a simple structure and practical and effective operation.

The technical features of the present invention, in accordance with the above aim, are clear from the content of the claims herein, in particular claim1and, preferably, from any of the claims directly or indirectly dependent on claim1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the accompanying drawings the numeral1denotes as a whole a hinge for wings or doors.

The hinge1is particularly suitable for mounting on an electrical appliance and, in particular, on a top loading washing machine, not illustrated.

In the known way, not illustrated, the top loading washing machine comprises a casing, or frame, to the sides of which a door—also not illustrated—is connected by two hinges1which allow it to rotate by tilting about a horizontal axis.

Each of the two hinges1comprises a bracket2intended to support a respective side of the door, a box-shaped body3, intended to be supported and completely enclosed by a respective side of the above-mentioned casing which is not illustrated, and a connecting lever4, which kinematically connects the bracket2and the box-shaped body3to each other.

The box-shaped body3has two lateral sides5, parallel with each other, which rotatably support the connecting lever4.

The lever4comprises a first portion4a, forming a respective cam6, which is described in detail below, and a second portion4b.

The first portion4aof the lever4forms a rotation pin by means of which the lever4pivots at two seats7made respectively on each of the sides5of the box-shaped body3so that the lever4and the box-shaped body3can move relative to each other tilting about the central axis A of the pin4a.

Once the door has been connected to the casing of the electrical appliance by the two hinges1, the axes A of the hinges form the axis about which the door can rotate by tilting relative to the casing.

The mechanical connection between the lever4and the door is made using the bracket2, illustrated with a dashed line inFIGS. 1 to 8and with a continuous line inFIG. 9.

The bracket2is L-shaped and has a first tab2a, fixed to the second portion4bof the lever4, and a second tab2b, extending at a right angle from the first tab2a, the second tab2bhaving a plurality of through-holes8so that it can be fixed using screws—not illustrated—to a respective side of the door, also not illustrated.

Suitably shaped cavities made in the pin4bon both sides form respective housings for the end of the first tab2aof the bracket2.

The presence of the two opposite housings guarantees use of the hinge1as a right-hand or a left-hand hinge.

In addition to the sides5, the box-shaped body3comprises a wall9connecting the sides5bridge-style, whilst it is open at the bottom, opposite the wall9.

Between the sides5, the box-shaped body3contains elastic means10designed to operate in conjunction with the first portion4aof the lever4to adjust the motion of the lever4relative to the box-shaped body3. The profile of the first portion4aforms the above-mentioned cam6.

The elastic means10comprise a rod11, a helical spring12wound coaxially around the rod11and a wheel13for contact with the cam6, rotatably supported by a fork14positioned at a first longitudinal end11aof the rod11.

The contact wheel13forms a follower designed to engage along the profile of the cam6.

At its second longitudinal end11b, opposite the first end11a, the rod11has an extended slot15, slidably connected to a first pin16fixed on the sides5of the box-shaped body3.

The helical spring12is pre-compressed and is inserted between the fork14and the first pin16.

The wheel13, supported by the fork14, is connected to the latter by a second pin17which has respective opposite end portions extending beyond the fork14and which slidably engage on respective guides18made on the sides5of the box-shaped body3.

The guides18, in which the end portions of the second pin17slide, define the path for the wheel13after rotation of the connecting lever4and the action which the latter exerts on the wheel13.

FIG. 1illustrates the hinge1in a first angular limit position in which the door connected to it is open, whilstFIG. 8illustrates the same hinge1in a second angular limit position in which the door is closed.

The reference for the angular movement of the door, and therefore of the bracket2, is the position adopted by the latter in the second, closed limit position. In other words, said position is assigned a zero value for the angle α, whilst, in the first, door open position, illustrated inFIG. 1, the same angle α is, for example, around 93°.

In practice, after rotation of the door, that is to say, of the brackets2about the respective axes A, the elastic thrust force exerted by the spring12acts on the lever4with a lever arm B which varies according to the angular position of the bracket2and therefore of the lever4.

In particular, the action of the spring12is variable and in agreement with that of the operator during the door opening step, whilst it is variable and opposing during the closing step, said closing step being exemplified by the succession of configurations illustrated inFIGS. 1 to 8. The variability of the action of the spring12is defined by the geometry of the lever4, that is to say, by the distance of the pins4band17, and by the geometry of the elastic means10.

Thus,FIGS. 1 to 8show a plurality of positions of the bracket2, and of the lever4which is integral with it, respectively corresponding to the door maximum opening position, six intermediate opening positions and, inFIG. 8, the door closed position.

The presence of the cam6means that the contact point with the wheel-type follower13, which is also the point for application of the spring12elastic reaction force F, and therefore the force F arm B, varies according to the angle α of rotation of the lever4about its axis A.

In particular, the cam6profile is shaped in such a way that, when the door is nearly closed, that is to say, close to the zero value of the angle α as illustrated inFIG. 8, the force F arm B is suddenly reduced so as to equally rapidly reduce the moment of the elastic reaction force F acting on the lever4, relative to the axis A.

Thanks to the above-mentioned shape of the cam6and to the effect derived, i.e.: the reduction of the force F moment, the following advantage is achieved: on one hand it is possible to balance the door opening/closing movement for most of its angular stroke and, on the other hand, it is possible, during closing, to have a force exerted by the door itself—that is to say, its weight force—which helps the door to close and facilitates activation of an electromechanical safety switch, if present.

In other words, the sudden reduction of the force F arm, and therefore of the torque acting on the lever4relative to its pivoting axis A, causes a simultaneous reduction of the balancing action exerted by the hinge1on the door and, consequently, for angles α close to the value zero, that is to say, close to the door closed position, the weight force of the door can usefully co-operate in the activation of the electromechanical switch located on the electrical appliance.

For example, with reference to the preferred embodiment illustrated, the table below shows the values of the force F arm B corresponding to the various angles α of opening for the door, and therefore the bracket2, as illustrated inFIGS. 1to8.

Said example should be considered indicative of the reduction of the length of the arm B from 12.1 mm to 6.3 mm between the value 10° and the value 0° of the angle α, a reduction quantifiable in percentage terms as greater than 40%.

Advantageously, according to embodiments of the present invention not illustrated, said percentage reduction is achieved within an arc not greater than 5 sexagesimal degrees and, preferably, of around 2-3 sexagesimal degrees.