SPRUNG STRUCTURE FOR ARTICLES OF FURNITURE OR THE LIKE

Abstract: The invention relates to a structure (10) for springing parts designed to support the weight of the human body in articles of furniture, automobile seats and similar products, of the type comprising at least one woven fabric/rubber elastic belt (16) tensioned between two opposite sides of the frame (26, 26') of the article of furniture or the like. To make the assembly as simple as possible and reduce the stresses on the article involved, the structure comprises a substantially rigid U-shaped support (12, 14, 14') fitted with means of attachment (24) to the frame (26, 26') of the article of furniture or the like, as well as a means (18) for retaining the elastic belt in tension between the two wings (14, 14<1>) of the U-shaped support.

Description: "SPRUNG STRUCTURE FOR ARTICLES OF FURNITURE OR THE LIKE" Technical Field The present invention relates to a structure for the springing of parts which support the human body in articles of furniture, automobile seats or similar products, such structure being of a type comprising at least one woven fabric/rubber elastic belt tensioned between two opposite sides of the article frame. The invention also relates to the articles of furniture having said structure and to a method for the application of the structure to said articles. Background art The articles of furniture involved in the present invention, e.g. seats, armchairs, divans, beds and others, as to automobile seats, are normally formed of a support and a padding. The support may be of various materials - wood, metal, plastic - and comprise at least one frame to which are attached spring elements to support at least in part the weight of a human body. Traditionally, the spring effect is achieved by usually vertical metal springs, but other systems have been foreseen: horizontal springs, strips of leather or wooden battens arranged transversely to the supporting frame. In more recent times fabric-Woven pre-tensioned elastic belts have been introduced which, being more reliable and durable than the springs, give better anatomic and ergono ic performance. The elastic belts are attached to the frame at the time of assembly of the article of furniture, and are tensioned and hooked to the frame in predetermined positions, often being interlaced. This application creates an increase in labour cost for the manufacturer of the article of furniture involved - in so far as it is necessary to manually stretch a relatively large number of elastic belts, interlacing them where necessary - and creates transverse stresses on the frame. Furthermore, the springing obtained with elastic belts does not have the classic bulging finished appearance of traditionally upholstered products which is easily obtained with vertical metal springs and which is demanded by buyers in as much as it visually seems to confer greater anatomic adaptability to the product. Disclosure of the invention Based on this premise, it is now an object of the present invention to provide a sprung structure of the type and for the applications indicated, which allows to eliminate the operations of tensioning and affixing the elastic belts to the frame of the article being produced, 'at present carried out manually by the manufacturer of the article. Another object of the present invention is to provide a sprung structure of the type and for the applications indicated, using an elastic belt as the main springing element, which is able to reduce the stresses on the frame of the article of furniture or similar product. A further object of the present invention is to provide a sprung structure of the type and for the applications indicated, using an elastic belt as the main springing element, which can give a finish similar to the classic upholstered appearance as obtained with traditional springs. A further object of the present invention is to provide a sprung structure of the type and for the appl ications indicated , allowing to obta in a high guality springing function in the article involved , by using fewer elastic belts than are used at present by elastic-belt springing systems . The objects of the present invention are achieved also by the patented method forthe production of the article of furniture or similar product with the aforementioned sprung structure, as well as by the article itself, comprising such a structure. To achieve the above shown objects, the present invention relates to a structure for the springing of parts designed to support the weight of the human body in articles of furniture, automobile seats and similar products, of a type comprising at least one woven fabric/rubber elastic belt tensioned between two opposite sides of the frame of the article of furniture or similar product, characterized in that it comprises a substantially rigid U-shaped support having means of attachment to the frame of the article of furniture or the like, as well as a means of retention of an elastic belt in tension between the two wings of said U support. Best mode for carry out the invention The invention will now be described in detail with reference to the attached drawings, in which : Fig. 1 diagrammatically shows a side view of an example of sprung structure according to the invention; Fig. 2 shows a simplified perspective view of the frame of an armchair which incorporates two sprung structures according to fig. 1. Fig. 3 shows a sectioned prospective view of the metal support of the structure as shown in figs 1 and 2. Figs. 4 and 5 are cross-section views through the planes IV-IV and V-V respectively in fig. 3. Fig. 6 shows a partial prospective view of the method of hooking the belt to the support in the examined structure. Fig. 7 diagrammatically shows a side wiew of an example of sprung structure provided with a slidable holder for the spring. Fig. 8.a and 8.b show a bottom wiew and a partial cross- section side wiew, along the two semi-planes VI-VI, of the slidable holder for the spring. Fig. 9 shows a top wiew of the slidable holder for the spring. With reference to fig. 1 , the sprung structure according to the present invention is referred to generically as 10, and comprises essentially a U-shaped elongated support having a base 12 and two shorter side wings 14, 14'. In the shown embodiment, the side wings 14 and 14' are inclined outward from the base 12 but they could be shaped differently, however within the limits imposed by the considerations to be presented below. Said base and side wings preferably form a single compact body. e.g. in the form of a rolled metal profile or in any case in a rigid or substantially rigid material. Always with reference to fig. l, the free ends of the wings 14, 14' are connected by a length of a woven fabric/rubber elastic belt, fitted under suitable tension and bound by its extremities to the ends of said wings 14, 14' in correspondence with its length extension and, preferably, by hooks or similar attachments 18, 18*. The latter may be fitted previously by techniques already known, to the extremities of the length of elastic belt with a platelet, and can be inserted into a suitably- shaped aperture in the ends of wings 14, 14', as will be described below. It should be noted that this hooking operation is carried out on a small-sized component which is substantially two-dimensional and standardized, and can be consequently easily mechanized, thus achieving considerable saving with respect to the substantially manual application of the belts by the manufacturers of articles of furniture or similar products. The belt is made up by interweaving suitably covered rubber filaments with substantially anelastic filaments in the warp and the weft, according to a well known technique. It has been found that it is appropriate to provide for lengths of fabric/rubber belt that are 80 millimetres wide and have a maximum elongation of 14%, which are mounted with a pre-tension which gives an elongation of 2 - 3%. A compression spring 20 is preferably fitted between the belt 16 and the base 12 of the rigid support, said spring being fixed on the base 12 with its lower end, while its upper end bears against the elastic belt 16, deforming it slightly in a direction away from the base 12, thus giving, inter alia, the bulging effect demanded by the sector. Preferably, the spring 20 is a conical spring, and its greater diameter bears against the belt 16. The spring may be positioned at the mid-point of the structure, but it is better if it is towards one end of the structure, to give the said bulging effect in the required position and to give a better anatomical shape. Obviously, a plurality of springs may be fitted to the structure, but such has not normally been found to be desirable in as far as no substantial further advantages are gained over the (more economical) use of one spring. The structure is completed by means of attachment of the same to the frame of the article of furniture or similar product, which means are formed by an extension 22, 22' of the upper wings 14, 14' forming an integral part of the same, having holes bored to take screws, nails or similar fasteners. Two screws 24, 24' for fixing the rigid sprung structure to two opposite beams of the frame of the seat (indicated generically by 26, 26)' are shown in fig. 1. Other forms of attachment are also possible, as it is obvious to any expert in the art. According to the present invention, the sprung structure as above described is incorporated into an article of furniture by fixing its ends 22, 22' to two opposite beams of the frame of the seat, armchair, divan or similar product, so that the elastic belts 16 are in line with the frame or in any case correctly positioned to carry out their springing function. To achieve the objects of the present invention, two or more of the structures as above described are fixed parallel to each other on the same frame, depending on the size of the same frame. It has generally been found that, in the case of a seat, the best results have been found by attaching the structures to the back and forward cross- members of the frame, and that, due to the combined effect of the elastic belt and the metal spring, two structures alone are usually sufficient for the seat of an armchair or similar product, giving a perfectly anatomical support with considerable savings on material and labour compared to the known art. The springing structure according to the present invention is simple to produce and, above all, its production can be mechanized. Furthermore, it is easy to fit, as it will appear obvious to an expert in the art, unlike the systems of the present state of the art. It is a good combination of comfort and mechanical endurance and, thus, of durability; it drastically reduces the stress on the frame of the furniture component which supports it, thereby enabling a different, lighter frame to be used, since it no longer has to withstand the traction forces of the belts but only and exclusively the weight of the user. Fig. 2 shows an exemplary application of the sprung structure now described to the seat of an armchair. In this figure the frame of the armchair is generically indicated by reference 30; it comprises a back 32 with wings 34, 34', two arms 36,36', legs 38, 38'.... The frame of the seat comprises a front cross-member 40, a rear cross-member 40' and two lateral members 42, 42'. As indicated in the figure, in this particular embodiment there are two sprung structures 10a, 10b as described above attached to the frame cross-members 40, 40'by their ends. The sprung structure of the present invention is of wide application and can be used not only in armchairs as described above, but also in divans, in all kinds of padded seats, in vehicle seats, and in beds - as spring to support the mattress. The sprung structure can be used in various parts of the seat e.g. in the backrest, when it is necessary or desirable. Figs. 3 to 6 show a particularly advantageous embodiment of the support 12, 14, 14' which supports the belt and the spring 20. As it can be seen from the figure, the support is made from a rolled metal profile e.g. in 12/10 mm P 01 sheet steel rolled to a W-profile to increase its moment of inertia and therefore its resistance. The two lateral walls 44 and 46 of the W-profile are forced toward the central fold 48, as shown in fig. 4 to retain the lowest coil 50 of the spring 20. Furthermore, at the junction of the base 12 and wings 14, 14' of the support, where the U profile bends, the two lateral walls 44 and 46 of the W-profile are inwardly bent as shown in figs. 3 and 5 to contribute in a substantial manner in obtaining a high strength of the support to the stresses of the belt tending to pull the two wings 14, 14' towards the centre, varying the angle which these wings 14, 14' form with the base or the horizontal plane. This angle (fig. 1) must be a compromise between the need to gain the maximum resistance to the stress imposed by the belts on the support wings 14, 14' and the need to leave sufficient room for downward movement of the platelet 52 (fig. 6) which connects the belt 16 to the hook 54 which is inserted into the hole 56 of the extension 22 of wings 14 and 14' , which also has at least another hole 58 to mount it to the frame of the armchair or the like. Said angle must be less than 90° but greater than 45° for the reasons stated above, the preference being for 55- 60°. With reference to Fig.7 the sprung structure 10 can be complemented with a slidable holder 101, positioned on the base 12 of the U-shaped support. The slidable holder 101 has the function of holding a coil of the spring 20, while the other extremity of the spring is positioned under the elastic belt 16. By variyng the position of the holder, and consequently of the spring 20, over the base 12 along the directions of the double arrow A, the elastic belt 16 assumes other configurations, (in the example of Fig. 7, when the spring is in the position 20', the elastic belt is in the position 16') . In this way the shape and also, if desired, the tension of the elastic belt and of the furniture can be varied according to necessity. It is also possible to use two or more holders, in different positions on the U-shaped support, each one holding a spiral spring, to make the elastic belt assume the desired configuration. As can be seen in Fig. 8. a and 8.b, the -slidable holder 101 for the spring 20 is composed of a small plate 102 which holds two nips 103, each one of them being provided with an hole 105. On the bottom of the plate 102 there is a guide 104 which allows the holder 101 to be slidably positioned on the U-shaped support 12. Fig. 9 shows a top wiew of the holder 101 in which are visible the nips 103 with their holes 105 over the plate 102. The holes 105 hold in position the coil of the spring 20.

Claims: CLAIMS 1. A structure for the springing of parts designed to support the weight of the human body in articles of furniture, automobile seats and similar products, of the type comprising at least one woven fabric/rubber elastic belt tensioned between two opposite sides of the frame of the article of furniture or the like, characterized in that it comprises a substantially rigid U-shaped support having means of attachment to the frame of the article of furniture or the like, as well as a means for retaining an elastic belt in tension between the two wings of said U support. 2. A structure according to claim 1, characterized in that it comprises at least one spiral spring, positioned in compression between the base of said U-shaped support and the elastic belt. 3. A structure according to claim 2, characterized in that the spring or springs are mounted each on a slidable holder allowing the regulation of the position of said spring(s) along the base of said U-shaped support. 4. A structure according to claim 3, characterized in that said slidable holder comprises a plate provided with a guide for being engaged on said U-shaped support base and means for coupling said spring to said plate. 5. A structure according to claim 4, characterized in that said means for coupling said spring to said plate comprise at least one nib with a hole for holding one end of said spiral spring. 6. A structure according to claim 2, characterized in that said spring is conical and its major diameter end bears against the elastic belt. 7. A structure according to claim 2 or 6, characterized in that the spring is positioned offset from the mid-length centre of the rigid support. 8. A structure according to claim 1, characterized in that the elastic belt is connected to the free end of the wings of the rigid support by means of hooks and belt-hook connector platelets. 9. A structure according to claim 1, characterized in that said support attachment means comprise one piece extensions on the ends of the wings of said U support, said extensions having holes for the passage of screws, nails or similar fasteners. 10. A structure according to claim 1, characterized in that said elastic belt has a maximum elastic extension of about 14% and is fitted to the support with a pre-tension sufficient to extend the belt by 2 - 3%. 11. A structure according to claims 1 to 10, characterized in that said elastic belt has a width of about 80 millimetres. 12. A structure according to any of the preceding claims, characterized in that said U-shaped support comprises a W- section rolled steel profile. 13. A structure according to claim 12, characterized in that the side-walls of said W-section metal profile are inwardly bent at the junction of the base with the wings of said U-shaped support. 14. A structure according to claim 12, characterized in that the side-walls of said W-section metal profile are inwardly bent at the location(s) in which the conical spring(s) are mounted to retain the lowest spiral of the spring(s) . 15. A structure according to claim 12, characterized in that the angle formed by the wings of said U-shaped support with the extension of the base of the same, is between 45° and 90°. 16. A structure according to claim 15, characterized in that the angle formed by the wings of said U-shaped support with the extension of the base of the same is of the order of 55° - 60° 17. A method for the assembly of a structure according to at least one of the preceding claims onto an article of furniture, automobile seat or similar product, characterized by the step of attaching said structure at the ends of the wings of the U-shaped support to two opposite cross-members of the frame of said article of furniture or the like, the elastic belts facing outward to support a cushion or the like. 18. An article of furniture, such as a seat, armchair, divan, bed, chair or similar product, characterized in that it comprises at least one sprung structure according to the claims 1 to 16. 19. An article according to claim 18, characterized in that it comprises two or more sprung structures parallel to each other in a plane of support of at least a part of the human body.

Inventors: FONTANA ANACLETO, FONTANA, ANACLETO
Applicants: CINTEL S A S DI FONTANA PAOLA, FONTANA ANACLETO, CINTEL S.A.S. DI FONTANA PAOLA & C., FONTANA, ANACLETO
Application year: 1995
Main classification: A47C7
IPC codes: A47C7