The spring hinge is formed of two elements, one is steady and the other is rotating around a pivot that keeps them fast, and at least four springs which push eight steel balls against two plates, having at least four holes slightly smaller than steel balls diameters.

Said hinges have been used over all as door hinge for vehicle (see DE- 8627459) to have some position of fixed openings. That hinge had balls engaged in a cage, these balls went to settle in depression formed in the rotating element of the hinge. This solution presented several inconveniences: - it happens to have rubbing friction between the face of the rotating element opposed to the one of the element having the depressions and one face of the steady element of the hinge; - the construction of the hinge was extremely complex and expensive; - to obtain that all the pieces fit each other, manufacturing precision had to be very high; - all the surfaces which rub each other need to be superficially hardened, raising still yet costs and difficulty of production. At last the hinge could be blocked open only in one position.

The principal purpose of the present invention is to have a spring hinge composed by a steady C-shaped element and by a rotating element wich

has a member that is inserted between the wings of the C-shaped element and by a pivot which crosses the wings of the C-shaped element and the member, in such a way to allow the rotation of the hinge characterized by the fact that to allow opening of the hinge in fixed position the member has an even number of holes, that in every hole it is inserted with accuracy a spring and two steel balls to both ends, that between the wings of the C- shaped element and the member are blocked two bored plates with even number of holes such as the even number present in the member and in axis with them but of a smaller dimension, that the plates are blocked between the wings of the C-shaped element and the member only by means of a face which lays against the internal face of the wing of the steady C-shaped element and of the pivot, that the plates have the same shape of the wings of the C-shaped element, that springs push the steel balls from both parts of the member against the two plates, that the steady position springs when the balls are inserted in the holes of the plates.

Another characteristic is given by the fact that to make easy the way back of the hinge in the initial position a spring is inserted on the same axis of the pivot and is arranged in a cavity obtained in axis with the pivot, in the member of the rotating element, that the spring is blocked with one end in a hole drilled in the member and with the other end in a hole realised in the adjoining plate Other characteristic is given by the fact that to have stronger or smaller forces in the way back it is enough to change the section of the spring which brings back contained in the cavity.

Other characteristic is given by the fact that the cavity obtained in the member of the rotating element holds grease to lubricate the hinge.

Other characteristic is given by the fact that the hinge reaches an opening angle of a maximum of 90" realised by means of the shape of the plate, of the wings of the steady C-shaped element and of the member of the rotating element.

Other characteristic is given by the fact that all the holes wich contain the springs and the steel balls are filled with lubricating grease.

Other characteristic is given by the fact that the hinge hinge reaches an opening angle of a maximum of 1800 realised by means of the shape of the plate, of the wings of the steady C-shaped element and of the member of the rotating element.

Other characteristic is given by the fact the number of the holes allow n/2+1 stop positions, being n an even number.

Other characteristic is given by the fact that plates are realised by means of superficially hardened steel.

Other characteristic is given by the fact that holes of the plates are obtained by means of punching.

Other characteristic is given by the fact that both steady C-shaped element and member rotating element are made of steel.

Other characteristic is given by the fact that both steady C-shaped element and member rotating element are made of wood, in this case holes for springs and balls are covered inside with a steel jacket.

Other characteristic is given by the fact that both steady C-shaped element and member rotating element are made of any material and that if this material is a not too hard material then the holes for the springs and balls are covered inside with a steel jacket.

Another purpose of the present invention is to provide an application of the hinge with the characteristic that the rotating elements of two hinges are connected with an arch in metallic material covered of cupper, that the steady elements of the two hinges are assembled on two rods in their turn assembled to the cross-bar of a bed, that in the superior part, the two rods are inserted in two metallic jacket which interfering with the two holes made in the cross bar of the bed keep the hinges to the height of the mattress that, from the inferior part, rods are blocked to the cross-bar of the bed with two torsion springs.

Other characteristic is given by the fact that arch, in the position all folded, allows to make normally the bed and the arch is not visible. In this position the way bak spring is charged, that when man wants to go to bed it is enough to catch arch, without raising blankets, and to bring it in the desired position (high for adults of medium-big body, middle for children or person of medium-small body).

Other characteristic is given by the fact that the arch will support blankets to the desired height and that in the bed it will be created a thermic room which shall have benefic effects on man which lies internaily.

Other characteristic is given by the fact that arch is covered with a cupper jacket which, being a good heat conductor, will assume fastly the temperature of of the thermic room created in the bed.

Other characteristic and advantages of the invention will appear evident from the following description of some embodiment of the invention given as example from figures 1, 2, 3, 4, 5, 6, 7, 8 e 9.

Fig. 1 represents a cross-section of an embodiment of the invention.

Fig.2 represents a view of the hinge with an opening angle which reaches a maximum of 90"; Fig.3 represents a cross-section of an embodiment of the hinge with way back spring; Fig.4 represents a view of the hinge with an opening angle which reaches a maximum of 1800; Fig.5 represents a cross-section of an embodiment of the hinge with holes covered with a metallic jacket; Fig.6 represents a perspective view of the of the principal elements which form the hinge with an opening angle which reaches a maximum of 90"; Fig.7 represents a perspective view of the of the principal elements which form the hinge with an opening angle which reaches a maximum of 1800; Fig.8 represents a lateral view of an application of the hinge to a bed for theraupetical purposes too; Fig.9 represents a front view of an application of the hinge to a bed for theraupetical purposes too.

Referring to fig.l the hinge is composed of a steady element I connected to another rotating element 2. The element 1 has a C-shape where wings 4 and 5 have rounded ends 3 (see fig.2). Both wings 4 and 5 present a hole for casing a rod 6 which is forced on them. In the example represented in fig.l the rod 6 is constituted of a stem 6a with conical head in which is obtained an hexagonal cavity and a threaded hole 7 and of a screw with conical head 6b with hexagonal cavity to block the rod 6 by means of screwing in conical seats of wings 4 and 5 of element 1. In place of the screw with conical head can be used a bolt with hexagonal head, or the rod can be forced in the wings 4 and 5 so realising a permanent plugging.

Between wings 4 and 5 it is inserted member 8 of element 2. The member presents a series of holes 9 in even number which allows spring opening positions in a number equal to n/2+1 where n is the number of the holes. In every hole 9 a spring 10 and two steel bails find place, the balls (for example balls for ball-bearings) are superficially hardened and they may slide with precision in the hole 9.

Two plates 12, positioned from a part and the other of the member 8, are kept in place from wings 4 and 5 of the C-shaped element. The plates 12 are of parallelepiped form with a rounded angle 3 to allow rotation of the hinge. The plates 12 are blocked in the steady element 1 of the hige by means of the side 12a which lies on the internal face la of the C of the steady element 1 (Fig.6 and 7). The plates present a series of holes 13 in number equal to the one that we find on the member 8 of the element 2

and on the same axis of these. The holes 13 have a diameter inferior to the one of the steel balls.

The springs 10 push the steel balls 11 against the plates 12. When element 2 of the hinge rotate about the rod 5, steel balls 11, pushed by springs 10, roll on plates 12 against which are pressed. When steel balls 11 find holes 13 of plates 12 they spring inside in a position of temporary stop. Applying a force greater than the force by which springs 10 push steel balls in the holes 13 the hinge moves to spring in another position of temporary stop. Using springs of different section it can be changed the force to spring in the position of temporary stop.

Fig.2, representing a view of the hinge, allows to observe that without rounded ends 13 of wings 4 and 5 and rounded end 14 of member 8 it is not possible to get rotation of elements of the hinge, it would be realised, instead, a stopped connection between the two elements 1 and 2, and that in the embodiment of fig.2 it is possible only a rotation angle of a maximum of 90".

Fig.3 represents the cross-section of an hinge in which it is inserted a spring to make easy the way back. In the member 8 of the element 2 on the same axis of the hole that receives the rod 6 it is realised a casing 15 for a spring 18 which ends are blocked in holes 16 and 17 realised respectively in member 8 and in plate 12. Casing 15 is used also to contain grease to lubricate hinge. Also the holes 13 hold grease for the lubrication of the steel balls. When rotating element of the hinge 2 move round rod 6 the spring 18 is charged, greater is rotation angle and stronger will be the

elastic force of which is charged the spring 18 which will act in the way to bring back the hinge to the initial position, making easy the way back of the hinge.

Fig.4 representing a view of the hinge, allows to observe that without rounded ends 13 of wings 4 and 5 and rounded end 14 of member 8 it is not possible to get rotation of elements of the hinge, it would be realised, instead, a stopped connection between the two elements 1 and 2, and that in the embodiment of fig.4 it is possible only a rotation angle of a maximum of 1800.

Fig.5 represents a cross-section of a hinge in which the holes that receive springs and steel balls, are inserted metallic jacket, this in the cases the material with which is made the hinge is not sufficiently hard.

Fig.8 and 9 show an application of the hinge. An arch 20 is mounted on the rotating elements 2 of two hinges, steady elements 1 of the hinges are fixed to the cross-bar 23 to the foot of a bed 22. The arch 20 in the position (a) all folded, allows to make the bed normally and the arch 20 is not visible, because hidden under the blankets. In this position the way back spring 18 is charged. At night when man wants to go to sleep it is enough to catch arch 20, without raising blankets, and to bring it in the desired position (high for adults of medium-big body, middle for children or person of medium-small body). Catching arch 20 with all the blankets it is possible to make the bed instantly, besides action is faciiitated by the way back spring 18.

The arch 20 will hold blankets to the desired height. In the bed It will be created a thermic room which will have benefic effects on man which will lie inside Besides because blankets don't weigh on man who sleeps, the present invention is particularly indicated for whom has back pain discs hernia and disease of the back-bone in general. Experiences in course have demonstrated that with the present invention man can sleep better than with the weight of blankets on legs and with a sense of greater rest.

The arch 20 mounted on the hinges is fixed to the croos-bar 23 of the bed 22 with poles 26 covered with jackets 25 that are larger than holes 28 realised on the cross-bar 23 and keep in place arch 20 to the desired height. The poles 26 are blocked on the cross-bar of the bed by means of springs 26.

The arch 20 is covered with a jacket 24 of cupper which being a good heat conductor assumes fastly the temperature of the thermic room which will be created inside the bed.

The invention, it is expressely understood, is not limitated to the representation given by the drawings but it can receive improvements and modifications by the man skilled in the art without going out from the meaning of the patent.

The present invention allows numerous advantages and to overcome difficulties that could not be won with systems actyually on the market.