A perfected hinge for constraining doors to a respective support structure

Abstract: The hinge according to the invention, for the constraining of doors to respective support structures, is composed of: a box structure (2) associable to a door (3), a lever (5) kinematically connected, with one of its ends, internally to the said box structure (2) and associated with its other end to the support structure (4); it is further equipped with a rod (7) which is internally mobile to the box structure (2) and kinematically connected to an intermediate point of the lever (5) and subjected to the action of elastic means (8) which keep it in one of the stable extreme configurations which it can assume in the case of opening and respective closing of the said door (3); the rod (7) is equipped with a striker edge (9) which will meet, when the rod (7) is in its open-door configuration, a connecting pivot (10) which kinematically connects the lever (5) to the box structure (2).

Description: The invention relates to a hinge for pivotally attaching a door to a respective supporting frame, such as oven doors to the ovens themselves. Such hinge types are usually constituted by a box structure associated to the said door, by a lever pivoted with one of its ends internally to the said box structure and associated with its other end to the support structure, and by a rod arranged internally and longitudinally mobile to the said box structure, hinged at one of its ends at an intermediate point of the said lever and subjected to the action of elastic means anchored to the box structure. The elastic means, whether of the traction type or the compression type, keep the lever in one of at least two stable configurations, one corresponding to the open position of the door and the other corresponding to the closed position of the door. The lever exits from the box structure through a respective longitudinal slot with its end which is destined to be associated to the support structure. Usually, for technical reasons of greater functionability, the lever is arranged in proximity to an end of the box structure and the extreme transversal edges of the slot function as end-run strikers for the lever. In particular, the longitudinal wall of the box structure in which the slot is realised functions as the end-run striker for the lever in the configuration in which the door is closed and the nearby transversal lip, which normally delimits the said slot, functions as striker for the lever in the configuration in which the door is open. Such a hinge is disclosed for example in the FR-A-2 662 204. In this document is proposed a hinge which exhibits two end-run strikers for the lever in order to share the force caused by the door itself. It often happens that the open door is used as a plane on which the plates extracted from the oven are leant, for example, when the operator is checking the readiness of the plate contents. Considering that the oven temperature is usually very high, it is evident that the plate taken out will instinctively be placed near to the extreme edge of the door, so that the operator will feel less the internal temperature of the oven. Distancing the plate from the support structure means, however, increasing the moment which the weight of the plate exerts on the door, and, in the final analysis, on the support structure's supports which are in effect constituted by the said hinges. When the door is in its open position, the hinge is kept in the corresponding configuration only by the transversal lip of the box structure slot, on which the lever exerts a bending stress. At present, the box structure of the hinge is obtained by means of bending or pressing of a metal sheet of a certain thickness. Consequently, the transversal wall is also made of the same metal sheet which like the box structure does not present mechanical resistence to bending to ensure safe supporting of the aforementioned bending force. On the other hand, the present safety norms envisage that, when the door is in its extreme open position and weight is placed upon it, the hinge must be able to support a weight which is normally superior to the maximum bending resistence of the transversal wail thus structured. The simplest solution would seem to be that of casting the box structure, but this would be costly both for the manufacturer and the buyer. The norms further envisage that the hinges, when the door is open, apart from being able to withstand a determined weight, must also give when, for example, a greater weight than that permitted is placed on the door. This is particularly important in all cases where the oven is arranged in columns or stacked structures of a certain height, or when the oven is notably large. In these cases, indeed, if the hinge were too robust, a particularly heavy weight, for example that of a child climbing on the door or standing on it, might cause the overturning of the entire structure. The aim of the present invention is thus to structure a hinge of the afore-mentioned type in such a way that it is able to sustain considerable but limited weights placed on the open door, but which, at the same time, is economical and easily constructable. The invention, as characterised in the claims which follow solves the problem posed with a perfected hinge, in particular for the pivotal attachment of doors to their supporting frame, using a hinge as defined in claim 1. An embodiment of the invention is described in more detail in the description which follows, with the help of the accompanying diagrams that represent a preferred but neither exclusive nor limiting embodiment, and in which: Figures 1 and 2 show, in lateral view and with some parts removed and others sectioned in order better to evidence others, the hinge according to the invention in its extreme configurations of closed door and open door; Figures 3 and 4 show, in lateral view with some parts removed and others sectioned in order better to evidence others, a variant of the hinge of figure 1 illustrated in its extreme configurations of closed door and open door; Figure 4a shows the particular according to view A of figure 4; Figures 5 and 6 show, in lateral view with some parts removed and others sectioned in order better to evidence others, a further variant of the hinge of figure 1 illustrated in its extreme configurations of closed door and open door; Figure 7 shows a plan view of a particular of figure 6 and; Figure 8 shows, in longitudinal section and in enlarged scale, a different embodiment of some particulars of figures 1 to 4. With reference to the figures, the hinge according to the present invention for constaining doors to respective support structures is denoted by 1 and is essentially constituted by a box structure 2, a lever 5, and a rod 7 and elastic means 8. The box structure 2 is constrainable to a door 3 and is completely hollow. The lever 5 is kinematically connected with one of its ends to the inside of the box structure 2 and is constrained by its other end exiting from a respective longitudinal slot 6 in the box structure 2 to a support structure 4 for the door 3. The rod 7 is arranged longitudinally internally to the box structure 2 and is kinematically connected, with one of its ends, to an intermediate point of the lever 5. The elastic means 8 act on the other end of the rod 7, which elastic means 8 can be of the traction type (see figures 1,2 and 5, 6) or of the compression type (see figures 3 and 4). The difference lies only in the fact that the traction-type elastic means 8 are arranged internally to the box structure 2 and are anchored, at one end, to the free end of the rod 7 and, at the other end, to the box structure 2. The compression-type elastic means 8 are instead fitted on the rod 7 externally to the box structure 2 and are squeezed between the said box structure 2 and a striker, for example a couple of diametral tabs 13 made out of the said rod 7 by means of external-direction bending of the said diametral tabs 13. Such hinges are destined to be arranged with their respective hinge axes horizontal and are normally applied along the lower edge of the door 3 which is therefore mobile between a practically horizontal open position and a practically vertical closed position. According to the present invention, the rod 7 exhibits a striker edge 9 destined to come into contact, when the lever 5 is in its open-door configuration, with a kinematic connecting pivot 10 for the lever 5 and the box structure 2. In reality, since the rod 7 is usually made by sheet metal bending and working, it exhibits two striker edges 9 and not one alone as described, but the said striker edges 9, seen laterally, coincide, and in any case act in synchrony in such a way as to be considered as one entity. This characteristic is fundamental for both types of hinge 1, whether of traction type elastic means (see figures 1 and 2) or of compression type elastic means (3 and 4). This striker edge 9 can be realised by widening the said rod 7: since the said rod 7 is arranged longitudinally in the box structure 2 and moves axially inside the said box structure 2 on action of the lever 5, the striker edge 9 call act on the connecting pivot 10 with shearing stress. It follows that, since the rod 7 is often made by sheet-metal pressing, it will sustain without undue problems the shearing stress which it exerts on the connecting pivot 10. The same connecting pivot 10 can be made stronger with respect to preceding ones since it can be made in various ways and in various materials without becoming prohibitively expensive. At the same time, a slot 17 is cut into the rod 7, which slot 17 creates a diaphragm 171 of thickness r. The slot 17, obviously, reduces the shearing stress resistance of the rod 7 and, by imposing a certain value for the thickness r of the diaphragm 171, the maximum value of the weight that can be laid on the door 3 before the hinge 1 gives way can be accurately and easily regulated. Obviously, the hinge 1 gives way in such a way that the door 3 can rotate further than its open position only by a certain value, usually sufficient to remove the danger of a possible tilting-over of the support structure 4. Such a value is defined by the transversal width of the slot 17 itself. In order to distribute better the loads which the lever 5 transmits to the rod 7, an abutment 11 is envisaged in the said rod 7, which abutment 11 is destined to strike, when the lever 5 assumes its configuration in which the door 3 is open, an internal ledge 12 recessed into the box structure 2 (see figures 2, 4 and 6). The abutment 11 and the respective internal ledge 12 are of flared shape so that alone they are not able to support the maximum accepted weight. This means that the abutment 11 and the internal ledge 12 act only synergically with the striker edge 9 and the relative connecting pivot 10. Thus it is evident that the hinge 1 according to the present invention is decidedly more robust that those of the prior art, but does not incur costs which inhibit its production. In figure 4 the compression-type rod 7 conformation is illustrated.: it is made in two successive lengths 71, 72, the first of which 71 is hinged to the lever 5 and exhibits a transversal "U"-shaped section. The successive length 72 has a transversal section which exhibits two flat parallel surfaces destined to be coupled internally to the "U" shaped section of the first length 71. The said first length 71 has, at its coupling end with the second length 72, a cross-member 711 destined to be coupled with a seating 721 bored into the corresponding end of the second length 72 and to form with the said second length 72 a rapid on-off coupling. At its free end exiting from the box structure 2 through a corresponding shaped hole, the second length 72 has two transversal tabs 13 jutting out of the said hole and destined to hold the elastic means 8, which elastic means 8 is usually constituted by a helix spring. As for the assembly of the rod 7, the second length 72 is inserted into the spring 8 and then into the corresponding hole in the box structure 2, thus pressing the said spring 8 into the first length 71 in such a way that the seating 721 engages with the cross-member 711. The second length 72 exhibits, in proximity to the transversal tabs 13, a plurality of holes 722 into which, after having compressed the spring 8, pivots (not illustrated) can be introduced at will to define the loading of the said spring 8 (obviously only the pivot relative to the determined load value of the spring 8 will be inserted). Looking at figures 1 to 4, it can be noted that the lever 5 is pivoted directly to the box structure 2 by means of the connecting pivot 10, and that the rod 7 is directly hinged to the said lever 5. The striker edge 9 will thus strike the connecting pivot 10 of the lever 5 with the box structure 2 (of figures 1 to 4). The embodiment of figure 8 envisages that the rod 7 is associated to a tracer wheel 18 in contact with the profile of the lever 5. The runner 18 is constituted, in the illustrated embodiment, by an idler wheel 181 borne by a forked body 182 arranged internally to the rod 7, longitudinally to the said rod 7 and freely passing through a transversal tab 183 bent towards the inside of the rod 7 itself. A spring 184 acts on the forked body 182 which spring 184 keeps the idler wheel 181 in contact with the profile of the lever 5. The said profile of the lever 5 exhibits a seating or recess 19 whose edges are differently conformed so that, when the door 3 is opened, a force is exerted on the hinge which is able to favour the opening of the door, and when the door 3 is closed, the hinge is subjected to another force which hinders the door's 3 closing. In effect the tracer wheel 18 acts as a damper for the door during the closing phase and, with the collaboration of the recess 19, defines an intermediate position which is relatively stable for the door 3. The damping function of the tracer wheel 18 is envisaged since when the door 3 is closed, the elastic means 8 of the hinge 1 is gradually unloaded, but the moment generated by the weight of the door 3 is reduced more rapidly so that on the said door 3 a gradually growing force which force tends to cause the door 3 to strike violently against the support structure 4. In figures 5 to 7, the lever 5 and the box structure 2 are reciprocally kinematically connected by means of a pair of link rods 14 and 15 articulated to them and with them constituting an articulated quadrilateral 16. The connecting pivot 10 is a hinging pivot of one of the said link rods 14 and 15 and the rod 7 is hinged, through a pivot 7f, to an intermediate point of the link rod 14 hinged to the connecting pivot 10. In this case, the striker edge 9 of the rod 7 will strike the connecting pivot 10 of the link rod 14 to which the rod 7 is hinged. The pivot 7f is mobile inside a slot 14a bored into the link rod 14 which link rod 14 is hinged at 14f to the lever 5. The groove 14a has two functions: the first is to allow the movements of the articulated quadrilateral 16 and the rod 7; the second is to increase the force with which the lever 5 is pulled towards the door 3 or, more clearly, the force with which the door 3 is pushed towards the support structure 4. Looking at figure 5, it can be noted that the groove 14a develops from an area near to the conjunction line y of the axes of the pivots 10 and 14f, along a direction which is more or less straight and towards the pivot 14f and the support structure 4. In this way, the pivot 7f is brought in proximity to the conjunction line y when the door 3 is open and it moves along the groove 14a, nearing the pivot 14f by the action of the elastic means 8 when the door 3 is closed. In this configuration the pivot 7f is distant from the vertical line passing through the pivot 10 axis by a quantity b: since the elastic means 8 act on the pivot 7f, the said elastic means 8 exert on the link rod 14 a moment whose arm coincides with b. The connecting pivot 10 is, however, mobile, so that the said moment is unloaded on to the pivot 14f and causes a rotation of the link rod 14 with the nearing of the connecting pivot 10, and with it the box structure 2 and the door 3 to the support structure 4. The size of the groove 14a, and especially its maximum distance from the convergence y determines the value of the moment arm with causes a nearing of the door 3 to the support structure 4. In both cases the striker edge 9 of the rod 7 will meet the hinging or articulation pivot 10 of the kinematic organ to which the rod 7 is hinged. One advantage of the present hinge is that although it is stronger that those of the prior art, it has no need of size or structural variations which would modify its dimensions with respect to the said prior art hinges, so that a substitution of this hinge for another can be performed without the need to adapt the door or support structure for the new hinge. Further, the strength of the present hinge is a point in its favour as regards the safety aspect. The conformation of the groove 14a permits of advantageously increasing the closing force of the door 3 without increasing the load of the elastic means 8, that is, without overloading them. The use of the tracer wheel 18 and of the respective recess 19 makes the door 3 closing movement gentler.

Claims: A hinge for pivotally attaching a door to a respective supporting frame, which hinge (1) is of the type constituted by: a box structure (2) fixedly mountable on a door (3), a lever (5), a first end of which is located within, and is pivotally connected to the said box structure (2), the second end of said lever (5) exiting from said box structure (2) through a respective slot (6) for fixed connection to said supporting frame (4), and a rod (7) longitudinally arranged internally of, and longitudinally slidable within said box structure (2) and pivotally connected at one end to an intermediate point of said lever (5) said rod (7) being subjected to the action of respective elastic means, (8) for maintaining said rod (7) in one of at least two extreme stable configurations in which said door (3) is respectively either open or closed, said rod (7) comprising at least one striker edge (9) destined to meet, when said rod (7) is in the configuration in which the door (3) is open, a connecting pivot (10) pivotally linking said lever (5), with said box structure (2), characterised by the fact that said rod (7) exhibits, in proximity to the striker edge (9), a weakening slot (17) realising a diaphragm (171) of a thickness (r) so related to the maximum weight allowable on said door (3) that the placing of a weight above that of said maximum weight on the door (3) will cause the said diaphragm (171) to yield. A hinge as in claim 1, characterised by the fact that the said rod (7) exhibits an abutment (11) destined to strike, during its longitudinal movement relative to the said box structure (2) and when the said lever (5) reaches its open-door configuration, against a respective internal ledge (12) realised internally to the said box structure (2). A hinge as in claim 1, wherein the said rod (7) is directly hinged to an intermediate point of the said lever (5), characterised by the fact that the said striker edge (9) of the said rod (7) will strike the connecting pivot (10) of the said lever (5) with the said box structure (2). A hinge as in claim 1, wherein the said lever (5) and the said box structure (2) are pivotally interconnected by means of a first link rod (14) and a second link rod (15) with which they define an articulated quadrilateral (16) and in which the said rod (7) is hinged to the said first link rod (14), characterised by the fact that the striker edge (9) of the said rod (7) will meet the connecting pivot (10) of the said first link rod (14) to which first link rod (14) the said rod (7) is hinged. A hinge as in claim 4, wherein the said rod (7) is hinged by means of a respective pivot (7f) to the said first link rod (14), the said first link rod (14) being pivoted to the said lever (5) by means of a pivot (14f) of its own and to the said box structure (2) by means of the said connecting pivot (10), charactersied by the fact that the said pivot (7f) is slidably housed in a respective slot (14a) bored into the said first link rod (14) and is able to permit the said pivot (7f) to reach, by the action of the said elastic means (B) during the closing phase of the said door (3), a relative position which is distant from the conjunction line (y) of the said hinging pivots (10 and 14f) axes of the said first link rod (14) and in such a way as to generate an increase in the compression force of the said door (3) towards the support structure (4). A hinge as in claim 3, characterised by the fact that the said rod (7) supports a tracer wheel (18) to be so in contact with the profile of the said lever (5) that said tracer wheel (18) may be received in a seating or recess (19) portion of said profile ; the said tracer wheel (18) and the respective said recess (19) defining together a practically stable intermediate position for the said door (3) and being also aimed at exerting a damping effect on the said door (3) when in movement during its closing phase.

Inventors: ZANETTI AUGUSTO, ZANETTI, AUGUSTO
Applicants: NUOVA STAR SRL, NUOVA STAR S.R.L.
Application year: 1992
Main classification: E05F1
IPC codes: F24C15, E05D11, A47L15, E05D3