Compact furniture hinge

Abstract: A furniture hinge (10, 110) has a wing (11, 111) and a cup (12, 112) interconnected with each other by a lower link rod (14, 114) and an upper link rod (15, 115). A torsion spring (25, 125) is wound round a pin (21, 121) inside the wing and parallel to the pivots of the link rods so as to have a thrust arm (22, 122) which acts upon a protrusion (20, 120) of the lower link rod facing towards the pin of the spring to push the hinge towards the closed position during a last section of the movement. The pivoting of the lower link rod (14, 114) to the wing is substantially between the pin (21, 121) of the spring and the pivoting of the upper link rod (15, 115) to the wing. The torsion spring advantageously has a reaction arm (123) which rests on the lower link rod (114).

Description: This invention refers to a furniture hinge having an innovative solution in the spring-operated closing mechanism. In particular, the innovative disposition of the mechanism makes it possible to obtain "gently" closing compact hinges. For many years widespread use has been made of articulated furniture hinges provided with a spring-operated mechanism which enables the door to close automatically. Among these are some particularly interesting hinges from the commercial point of view which close "gently", that is to say which snap shut only at the last few degrees of closure, while remaining free for the remaining span of the movement. Various configurations of positioning and action of the spring-operated mechanism are known in the known technique. For example, use is very often made of a torsion spring wound round the pivot pin of the upper link rod of the hinge to act upon a cam protrusion on the lower link rod (see DE-A-2,851,774 and DE-U-89 09 532). EP-A-O 395 804, disclosing the features of the preamble of claim 1, suggests the use of a spring wound around a supplementary pin in the wing far from the pivots of the arms, to provide an intermediate hole to receive fastening means of the wing. In this structure of hinge, an arm has a reduced thickness and is provided with a projecting end acting on a thrust arm of the spring wound on the supplementary pin. This structure involves a number of disadvantages. The thin arm reduces the resistance of the hinge definitely, particularly against torsion efforts and is incompatible with small sized hinges. The rest of the single thrust arm of the spring against the projecting end of the thin arm is critical and uncertain, in view of the form tolerances of this kind of products and must be strictly guided, involving an asymmetrical shape of the wing. The need of realizing guides for the thin arm and the thrust arm of the spring requires a complex shape of the wing that cannot be formed with deep drawn sheets of metal, as usual. To obtain the required effort, the spring must have a section so large to involve an overall dimension not compatible with small sized hinges. These configurations, however, call for a relatively large space inside the wing. In particular, they call for a relatively large space between the pivot of the lower cam and the ceiling of the wing, each space having to accommodate the spring and the cam protrusion and permit their movement. This restricts the design of the hinge enormously, since the pivoting of the link rod has to be positioned well below the pivoting of the other arm, around which the spring is wound. This results in considerable limitation to the kinematic performance of the hinge. This inconvenience is all the more critical the smaller the hinge is. With the known solutions it is therefore virtually impossible to obtain "gently-closing" hinges of limited dimensions. For hinges of very limited dimensions it is consequently necessary to do without the "gentle" closure. The only expedient has been to place a leaf spring outside the wing, resulting in considerable problems in assembling the hinge as well as aesthetical problems. The general scope of this invention is to obviate the aforementioned problems, by providing a hinge with a spring-operated closing mechanism which, while retaining its features of "gentle" closure, makes it possible to produce a hinge of very limited dimensions, advantageously also providing extensive freedom in the positioning of the spring-operated mechanism and outstanding kinematic efficiency. This scope is achieved according to the invention by providing a furniture hinge as defined in claim 1. The innovative principles of this invention and its advantages with respect to the known technique will be more clearly evident from the following description of a possible exemplificative and non restrictive embodiment applying such principles, with reference to the accompanying drawings, in which: figure 1 shows a partially cutaway schematic side view along the line I-I of figure 2, of a hinge in the open position; figure 2 shows a schematic bottom view of the hinge of figure 1 in the closed position; figure 3 shows a partially cutaway schematic side view along the line III-III of figure 4, of a second hinge in the open position; figure 4 shows a schematic bottom view of the hinge of figure 3 in the closed position; figures 5 and 6 show partially cutaway schematic side views of a first and a second step of the assembly of the hinge of figure 3. With reference to the figures, figure 1 shows a hinge according to the invention, generically indicated by reference 10. The hinge 10 comprises a wing 11 and a cup 12 connected to each other by means of an articulation 13 composed of an arm or lower link rod 14 and an arm or upper link rod 15, pivoted respectively to the wing in 16 and 17 and respectively to the cup in 18 and 19. According to the known technique, the wing is designed to he secured to a furniture unit by means of known fastening means, for example adjustable, not shown, while the cup is designed to be secured in a complementary recess provided in a door. According to the innovative principles of this invention, wound around a further pin 21 transversal to the wing is a double torsion spring 25, for example, made of wire. The pin of the spring 25 is disposed in the wing so that the pin 16 of the lower link rod comes to rest between the pin of the spring and the pin 17 of the upper link rod. The lower link rod 14 has one end wound round the pivot 16 which comprises a lateral cam protrusion 20 directed into the space between the pin of the lower link rod and the pin of the spring and therefore substantially in the opposite direction to the pin 17 of the upper link rod. As can be clearly seen in figure 2, the protrusion 20 can be obtained by cutting and unfolding a central area of the same end of the link rod 14, made of folded sheet metal. The spring 25 has one thrust end 22 which rests on the cam protrusion 20 and a second end reacting on the wing. In particular, the second end of the spring is made in the form of parallel arms 23, each resting inside the ceiling of the wing. As can be seen in figure 1 from the comparison between the continuous line drawing (showing the open hinge) and the broken line drawing (showing the closed hinge) the closing movement of the hinge causes the spring to stretch. During the movement the cam protrusion remains beneath a line ideally traced between the centres of the pins 16 and 21. As will be obvious to the expert in the field, by suitably dimensioning and positioning the spring and cam protrusion to adjust the thrust arm on the protrusion according to the angle of rotation of the link rod, the closing action can be made to take place mainly at a desired angle near to the complete closing, so as to provide a "gentle" closing action. The action of the spring, directed upwards, is highly effective also due to the fact that proceeding towards the closure increases the arm applying pressure on the lower link rod, while it decreases the free arm of the spring, that is to say, the cam rests on the spring in a position increasingly nearer to its turns. From figure 1 it is obvious how a hinge according to the invention can be kept of limited dimensions, the reduction in height of the wing being in substance practically limited only by the external diameter of the coils of the spring. Due to the advantageous efficiency offered by the closing mechanism made according to the invention it is possible to use springs with a relatively limited thrust and, therefore, with a smaller wire thickness. Moreover, the pivoting point of the spring is outside the kinematic mechanism of the hinge and consequently the design of the hinge does not have to take the dimensions of the spring into account. Figures 3 and 4 show (indicating the elements similar to those of figure 1 by the same numbers preceded by one hundred) an advantageous variation to the hinge described up to this point. In this variation, the spring 125 is bent into an "alpha" shape so that the reaction end also rests on the end of the lower link rod 114. The reaction end rests in an area of the end of the link rod above the line of conjunction between the pin of the spring and the pivot of the link rod 114. In particular, as can be clearly seen in figure 4, the spring has reaction arms 123 which rest, in the vicinity of the lateral ends of the pivot 116, on a substantially cylindrical wound portion 124 of the end of the lower link rod 114. In figure 3 it can be seen that when the hinge 110 moves open, the lower link rod compresses the spring by means of the protrusion or tab 120, pulling the opposing ends 122, 123 of the spring apart from each other. Upon reclosure of the hinge, an efficient thrust action is obtained, as previously described for the embodiment of figure 1. In addition to the advantages described for the embodiment of figure 1, the fact that the spring 125 has resting points on the link rod and not on the wing permits considerable freedom in the positioning of the unit composed of spring 125 and link rod 114 inside the wing. In particular, the assembly composed of the pin 121 of the spring and the protrusion 120 can be ideally rotated around the pivoting axis 116 of the link rod, maintaining the functioning of the closing mechanism unchanged. This enables the designer of the hinge to more effectively exploit the space inside the wing and avoid restrictions. In this way, it is extremely simple to design particular hinges, such as for example those of the type with curved or swan-necked wings, even of limited dimensions. At this point it will be clear that the intended scopes have been achieved by providing a hinge with an efficient spring-operated closing mechanism which does not suffer from excessive dimensional restrictions. Hinges according to the innovative principles of this invention have further advantages compared to the known technique also as regards their manufacture. In fact, it is not necessary for example to preload the spring in order to be able to position it in the wing, as was necessary on the contrary in the known hinges. Figures 5 and 6 show an assembling sequence for assembling the spring and the lower link rod in the wing for the hinge of figure 3. As can be seen in figure 5, the spring is fitted and pivoted in the wing without any preloading whatsoever. After this the lower link rod is fitted in the wing with a simple rectilinear movement (in the direction indicated in figure 5), so as to be able to pivot it to the wing in a position with the protrusion 120 close to the end of the arm 122 of the spring, as shown in figure 6. Once the link rod and spring are pivoted, it is sufficient to rotate the link rod in the direction shown by the arrow in figure 6 to load the spring and shift the link rod into position to pivot it to the cup together with the upper link rod. The various assembling phases are consequently extremely simple and do not call for special complicated tools, as are required for the known hinges. If, when the spring is unloaded the arm 122 of the spring comes to rest with its free end over the line of conjunction between pins 16 and 21, it is sufficient for the arm to be of such length that the curve of the movement of the free end during the loading does not intersect the pin 116. In other words, the arm must be shorter in length than the free space between the pin of the spring and the pivot of the link rod. The assembling procedure for the hinge of figure 1 is obviously similar. At this point it will be clear that the intended scopes have been achieved by providing hinges with limited dimensions and a highly efficient closing mechanism. The foregoing description of embodiments applying the innovative principles of this invention is obviously given by way of example in order to illustrate such innovative principles and should not therefore be understood as a limitation to the sphere of the invention claimed herein. For example, thanks also to the innovative solution claimed herein, the exact shape of the hinge, the positioning of the parts and their relative size may differ from what has been shown in the figures. The spring and the link rod can also be made so that the cam protrusions are two in number, close to the two ends of the pin 16 and the spring rests on them by means of the two parallel arms 23 or 123, while the loop-shaped end 22, 122 constitutes the reaction end and rests either against the wing or on a cylindrical surface achieved by rolling the link rod around the pin 16 in a central position to the two protrusions.

Claims: A compact furniture hinge (10, 110) having a wing (11, 111) and a cup (12, 112) interconnected with each other by a lower link rod (14, 114) and an upper link rod (15, 115), each rod (15, 115) being pivoted on a pin (18, 19, 16, 17) at one end to the cup and at the other end to the wing, so that the wing and cup are reciprocally articulated so as to be movable between a closed hinge position and an open hinge position, a torsion spring (25, 125) having a thrust arm (22, 122) which acts on a cam protrusion (20, 120) on a portion of the end of the lower link rod (14, 114) which is pivoted to the wing to push the hinge towards the closed position during the last section of its movement from the open to the closed position, the spring (25, 125) being wound intermediate its ends round a pin (21, 121) inside the wing and parallel to the pivot axes of the link rods, said portion facing towards the pin (21, 121) of the spring, the pivot pin (16, 116) connecting the lower link rod (14, 114) to the wing being provided in the longitudinal direction of the wing substantially between the pin (21, 121) of the spring and the pivot pin connecting the upper link rod (15, 115) to the wing, characterized by the fact that the spring is of the double torsion type with a thrust arm formed by a central loop (22, 122) and a pair of substantially parallel reaction arms (23, 123), and the pin (21, 121) of the spring (25, 125) is located between the pivot pin (16, 116) of the lower link rod (14, 114) and the portion of the wing containing the openings for the adjusting and fixing screws. Hinge as claimed in claim 1, characterized by the fact that the torsion spring has a reaction arm (23) which rests on an internal portion of the wing. Hinge as claimed in claim 1, characterized by the fact that the torsion spring has a reaction arm (123) which rests on the lower link rod (114). Hinge as claimed in claim 3, characterized by the fact that the resting area of the reaction arm (123) is in correspondence with the end of the lower link rod pivoted to the wing. Hinge as claimed in claim 1, characterized by the fact that each arm (123) of the pair of reaction arms rests on the end of the lower link rod (114) pivoted to the wing close to the sides of the pivots. Hinge as claimed in claim 1, characterized by the fact that the cam protrusion (20, 120) runs along the thrust arm (22, 122) of the spring remaining below an ideal line of conjunction between pin (21, 121) of the spring and pivot (16, 116) of the lower link rod (14, 114) to the wing. Hinge as claimed in claim 3, characterized by the fact that the reaction arm (123) of the spring rests on the end (116) of the lower link rod (114) pivoted to the wing, in a position above an ideal line of conjunction between the pin (121) of the spring and the pivot (116) of the lower link rod (114). Hinge as claimed in claim 1, characterized by the fact that the cam protrusion (20, 120) is made in the form of an extended central portion of the pivoted end of the lower link rod (14, 114) which is made from bent sheet metal. Hinge as claimed in claim 1, characterized by the fact that the length of the thrust arm (22, 122) of the spring is shorter than the free space between the pin (21, 121) of the spring and pivoting (16, 116) of the lower link rod (14, 114) to the wing.

Inventors: FERRARI FRANCO, MIGLI CARLO, FERRARI, FRANCO, MIGLI, CARLO
Applicants: FERRARI FRANCO, FERRARI, FRANCO
Application year: 1996
Main classification: E05D11
IPC codes: E05D11, E05F1