A device to obtain a supplementary springing effect in supporting frames provided with elastic belts

Abstract: In order to provide a springing effect in correspondence with the edge (10') of a belt frame (10) in chairs, sofas or the like, a device is envisaged consisting of a plurality of arms (16), each fixed to a belt (12) and extending from the latter in inclined position, as well as a common transverse element (18) connecting all the arms. Due to stresses on the latter element, the arms deform the belts which cause a bending moment of elastic return.

Description: This invention relates to a device to obtain a supplementary springing effect in supporting frames provided with elastic belts for application in furniture components, car seats or the like, said spinging being carried-out parallely to at least one of the frame sides and over its plan, with at least a component perpendicular to the frame itself. It is known since long time the system of replacing the traditional metal springs with wowen elastic belts, which are stretched between opposite elements of rigid frames in order to obtain spinging in applications of the aforesaid type. Elastic belts have a lot of advantages versus springs, among which are longer duration and lower deterioration of the parts in contact with them, and actually their use is more and more widespread thus replacing metal springs. Nevertheless, a limitation of the belt frames consists in the fact that there is no springing effect in correspondence with the frame edges and mainly in correspondence with the front edge of the frame. A device which provides a supplementary springing effect in a belt frame is described in EP-A-015 331. This device comprises a plurality of arms extending over the front part of the sitting plane, each arm being mounted to an elastic belt and inclined with respect to the belts. The preamble of independent claim 1 is based on the above document. Another example of a springing assembly for seats and the like is described in US-A-3 057 613. This device comprises a plurality of transverse belts mounted over a frame element by means of a plurality of spaced resilient wire elements, said transverse belts supporting the sitting plane of the seat. A springing action is provided also by the device described in US-A-2 106 066, in which two elastic arms are mounted between the supporting frame and the sitting plane, in order to provide a resilient action on the sitting plane. The object of the present invention is that of providing a device of the previously defined type, which may be applied to any belt frame, even possibly already in place, to obtain supplementary springing, specially over one of the frame sides and in correspondence with a supporting area for the user's legs. For this purpose, the invention envisages a device as mentioned hereinabove and for the aforesaid uses, said device comprising a plurality of arms, each mounted on at least one belt in a slanting position with respect to the belt itself, said belts and arms cooperating to provide an elastic reaction to stresses tending to place the arms parallel to the belt, said arms returning to the initial position when said stresses are over, characterised in that said device further comprises a transverse element, mounted on the free ends of said arms, on which said stresses are meant to be exerted; and in that each arm is mounted to each belt and rests thereon in correspondence of at least two areas, of which one is on the belt side from which the arm extends and the other one is on the opposite side of the belt, spaced from the former one in a direction opposite to that of the arm in order to exert together with the first area a bending action on the belt after stresses have been applied to the arm, such as to elastically drive the arm again to the initial position. Various modifications of the device claimed in claim 1 are defined in claims 2 to 6. The different peculiarities and features of the device according to the invention will now be further described with reference to an embodiment, given by way of example and illustrated in the accompanying drawing, wherein: figure 1 is a perspective view illustrating an example of a device according to the invention, applied to a belt frame; and figures 2 and 3 are sectional views as indicated by II-II in figure 1, showing the preferred operating ways of the components of the device of figure 1. With reference first of all to figure 1, a normal frame 10, for instance a rectangular wooden frame, is provided with a certain number of belts 12, fastened in whatever proper way (schematized by 14) to two opposite sides of the frame 10, under a tension applied before the fastening, exploiting the elastic properties of the belts themselves. These latter can be applied in any number whatsoever, at fixed or variable reciprocal intervals, and can be also crossed by belts at 90 degrees. For simplifying the drawing, however, only three parallel and equally spaced belts have been represented, put under tension and hooked to the side 10' of the frame 10 which is supposed to correspond to the front side of the seat. To obtain the aforesaid springing effect, a device is foreseen whose major components are in the form of arms 16, each of which is fastened to a belt 12 in a way as to extend upwards in a slanting position starting from said belt and reaching, for the foreseen application, a point upward the side 10' of the frame. The uplifted free end of each arm 16 is connected, for instance snapwise, with a common transverse element 18, whose elastic displacements in the direction of the side 10' of the frame 10 therefore involve all the arms 16, compensating the different stresses to which they are submitted. In order to obtain the desired effect of elastic springing, the arms 16 could present intrinsic elasticity, for example being made of harmonic steel or other appropriate material, at least in correspondence with an area close to the belt. However, the preferred embodiment exploits for this purpose the elasticity of the belts, envisaging essentially rigid arms 16, which are coupled to each belt by way of two areas or supporting sections, respectively an upper section 20, placed on the side from which extends the arm 16, and a section 22 which engages the belt 12 underneath, namely on the opposite side to that of the arm 16 and in a spaced position along the belt, in opposite direction to the arm 16 with respect to the section 20, as better visible in figure 2, the sections 20 and 22 being rigidly connected by a small arm 24. In said conditions, if a force F (fig. 3) is exerted on the transverse element 18 and consequently on the arms 16, each of the latter exerts a bending moment on the length of the belt 12 between the sections 20 and 22, which causes the belt 12 to bend as visible in figure 3; the result is a reaction, due to the belt tension, tending to drive the arm 16 again to its rest position of figure 2 and therefore to create the desired springing effect. Furthermore, this tends to increase the belt 12 tension, improving its functional performance. As shown in figure 1, the transverse element 18 can not only be fastened to the arms 16, but also to the frame 10 by way of other terminal arms 26 which can merely have a driving function, being in this case hinged to the frame 10, or can on their turn exert a springing action, being fixed for instance by riveting in 28 to the frame 10 and being provided with at least an elastically deformable bent area 30.

Claims: A device to obtain a supplementary springing effect in supporting frames (10) provided with elastic belts (12) to be used in furniture components, car seats or the like, said springing device acting in correspondence with at least one of the frame sides (10') and above the sitting plane defined by said belts (12), with at least a springing force component (F) perpendicular to the frame (10) itself, said device comprising a plurality of arms (16), each mounted on at least one belt (12) in a slanting position with respect to the belt (12) itself, said belts (12) and arms (16) cooperating to provide an elastic reaction to stresses tending to place the arms (16) parallel to the belt (12), said arms (16) returning to the initial position when said stresses are over, characterised in that said device further comprises a transverse element (18), mounted on the free ends of said arms (16), on which said stresses are meant to be exerted; and in that each arm (16) is mounted to each belt (12) and rests thereon in correspondence of at least two areas, of which one (20) is on the belt side from which the arm (16) extends and the other one (22) is on the opposite side of the belt (12), spaced from the former one in a direction opposite to that of the arm (16) in order to exert together with the first area a bending action on the belt (12) after stresses have been applied to the arm (16), such as to elastically drive the arm (16) again to the initial position. A device according to claim 1, characterized in that said arms (16) are intrinsically flexible in an elastic way. A device according to one of the preceding claims, characterized in that the transverse element (18) is fixable snapwise to the free ends of said arms (16). A device according to one of the preceding claims, characterized in that said transverse element (18) essentially extends over the side (10') of the rigid frame (10) to which the belts (12) bearing the arms (16) are fastened. A device according to claim 4, characterized in that said transverse element (18) bears end arms (26) fixed or fixable to the frame (10) itself. A device according to claim 5, characterized in that said end arms (26) are intrinsically flexible in an elastic way.

Inventors: FONTANA ANACLETO, FONTANA, ANACLETO
Applicants: CINTEL S A S DI FONTANA PAOLA, CINTEL S.A.S. DI FONTANA PAOLA & C.
Application year: 1991
Main classification: A47C7
IPC codes: A47C7