NEWLY DESIGNED FLAT SPRING

Abstract

NEWLY DESIGNED FLAT SPRING The invention relates to a flat spring (1) comprising a central part (2) disposed between two end parts (3a, 3b); wherein the central part (2) has a corrugated shape extending over a plane, and said central part (2) has a flat, planar upper surface (20a) and a flat, planar lower surface. Figure to be published with the abbreviation: Figure 1

Description

Title of the invention: NEWLY DESIGNED FLAT SPRING

[0001] The present invention relates to a flat spring.

[0002] Various types of springs with different shapes and functions are known on the market.

[0003] Three-dimensional springs are known, such as helical springs, wave springs, leaf springs, clip springs, band springs, cup springs, and profile springs. Since these are three-dimensional springs, it is clear that these types of springs present problems in terms of volume, transport, handling, and warehouse storage. Furthermore, because they are three-dimensional, these types of springs have a rather complex design when it is necessary to modify the variables of mechanical strength, elasticity, and elongation of the spring.

[0004] Flat springs with a flat configuration are also known. Flat springs are obtained from a metal rod with a circular cross-section that is bent in a substantially sinusoidal wave pattern. This type of flat spring is commonly used in seat upholstery.

[0005] Although flat springs are suitable for solving problems related to volume and design complexity compared to three-dimensional springs, they have the disadvantage of exerting a weak elastic force relative to their volume.

[0006] Springs are also distinguished according to their function. Indeed, we know of compression springs, tension springs, and torsion springs. However, these three types of springs are different from one another or, in any case, have different attachments depending on their mode of operation.

[0007] In all cases, all prior art springs have construction drawbacks which arise from the design and construction of the spring end parts or the methods of attaching the spring end parts.

[0008] The objective of the present invention is to eliminate the disadvantages of the prior art by providing a flat spring that is compact and easy to store, transport and handle.

[0009] Another objective is to provide a flat spring that is versatile and capable of working in compression, tension or torsion without having to modify its structure.

[0010] Another objective is to provide a flat spring which is not limited to the type of end parts and which is suitable for all types of attachments to its end parts.

[0011] Another objective is to provide such a flat spring which can be easily designed, by modifying its variables in terms of mechanical strength, elasticity and elongation.

[0012] Another objective is to provide a flat spring that is efficient, reliable and simple to manufacture and install.

[0013] To achieve these objectives, the present invention relates to a flat spring comprising a central part disposed between two end parts, in which the central part has a corrugated shape extending over a plane, and said central part has a flat, flat upper surface and a flat, flat lower surface.

[0014] Advantageously, said central part of the spring comprises a plurality of undulations.

[0015] Advantageously, each undulation has a U-shape and comprises two straight sections connected to each other by a curved section.

[0016] Advantageously, each straight section of a corrugation has a rectangular cross-section and each curved section of a corrugation has a radial rectangular cross-section.

[0017] Advantageously, said curved section of each undulation has a semi-circular shape.

[0018] Advantageously, said undulations are identical to each other.

[0019] Advantageously, each straight section of a corrugation has a width, and between between the two straight sections of a wave there is a distance equal to the width of the straight section.

[0020] Advantageously, each straight section of a corrugation has a width, the central part comprising the straight sections and the curved sections has a constant thickness, and the ratio between the width of a straight section and the thickness of the central part is within the range of 4 to 8.

[0021] Advantageously, each end part comprises a plate having the same thickness as the central part.

[0022] Advantageously, said plate on each end part has a hole.

[0023] Other features of the invention will be better understood upon reading the detailed description below, which refers to a purely illustrative and therefore non-limiting embodiment, as shown in the accompanying drawings in which:

[0024] [Fig-1] is a plan view of a flat spring according to the invention;

[0025] [Fig.2] is an enlarged detail of [Fig.1], illustrating a single undulation of the spring dish according to the invention;

[0026] [Fig.3] is a cross-sectional view taken along section plane III-III of [Fig.2];

[0027] [Fig.4A] is a view as in [Fig.1], illustrating the flat spring according to the invention in voltage operating mode.

[0028] [Fig.4B] is a view as in [Fig.1], illustrating the flat spring according to the invention in compression operating mode.

[0029] [Fig.4C] is a view as in [Fig.1], illustrating the flat spring according to the invention in torsional operating mode.

[0030] With the aid of the Figures, a flat spring according to the invention, which is generally indicated with the reference number 1, is described.

[0031] With reference to [Fig.1], the flat spring 1 comprises a central part 2 disposed between two end parts 3a, 3b.

[0032] The central part 2 has a wavy shape which extends over a plane. The central part 2 has a flat upper surface 20a and a flat lower surface 20b ([Fig.3]).

[0033] The central part 2 comprises a plurality of undulations 20 which are identical to each other.

[0034] With reference to Figures 2 and 3, each undulation 20 has a U shape and comprises two straight sections 21 connected to each other by a curved section 22 in the shape of a semicircle.

[0035] Each straight section 21 has a rectangular cross-section. Similarly, each curved section 22 has a radial rectangular cross-section.

[0036] Each straight section 21 of the undulation 20 has a width W and a length L. It should be noted that the width W of the straight section 21 extends in a longitudinal direction of the spring, while the length L of the straight section 21 extends in a transverse direction of the spring.

[0037] The ratio between the length L and the width W of the straight section 21 is within the range of 4 to 8.

[0038] The width R of the curved section 22 measured in the radial direction is constant and equal to the width W of the straight section 21.

[0039] Between the two straight sections 21 of a corrugation 20, there is a distance D equal to the width W of the straight section 21.

[0040] With reference to [Fig.2], each undulation 20 has a length Lo given by the length L of the straight section 21 plus the length Lr of two curved sections 22. The length Lr of each curved section 22 is equal to 1.5 times the width W of each curved section 22, i.e. Lo = L + 3W.

[0041] Each undulation 20 has an amplitude A equal to three times the width W of each straight section 21, i.e. A = 3W.

[0042] It should be noted that the length Lo of the wave 20 extends in the cross-sectional direction of the spring, while the amplitude A of the wave 20 extends in the longitudinal direction of the spring.

[0043] The central part 2 comprising the straight sections 21 and the curved sections 22 has a constant thickness S.

[0044] The ratio between the width W of a straight section 21 and the thickness S of the central part 2 is within the range of 4 to 8.

[0045] If we return to [Fig.1], the central part 2 has the form of a periodic undulation with a period T equal to four times the width W of the cross section 21, i.e. T = 4W.

[0046] The central part 2 may include a number of undulations 20 in the range from 4 to 14.

[0047] Each end part 3a, 3b comprises a plate 30 with a central hole 31. The plate 30 has a substantially rectangular or trapezoidal shape with an oblique side 32 which is connected to a curved section 22 of the central part 2. In this way, a slot 34a, 34b is generated between the plate 30 of the end part and the curved section 22 at one end of the central part 2.

[0048] With reference to [Fig.1], the slot 34a in the end part 3a on the left side is formed between the plate 30 and a maximum curved section 22 of the corrugation 20. Conversely, the slot 34b in the end part 3a on the right side is formed between the plate 30 and a minimum curved section 22 of the corrugation 20.

[0049] The plates 30 of the end parts 3a, 3b have a thickness equal to the thickness S of the central part 2.

[0050] It should be noted that the plate-type shape of the end parts 3a, 3b allows the end parts 3a, 3b to be easily connected to any type of fastener.

[0051] Spring 1 can be made by cutting a harmonic steel plate for springs.

[0052] Alternatively, the spring 1 can be made of die-cast harmonic spring steel.

[0053] The plate-type structure of spring 1 allows the springs to be stored one on top of the other, with a minimum volume given by the sum of the thicknesses S of the springs.

[0054] Thanks to the rectangular section of the central part 2, the new geometry of the spring 1 makes the spring particularly strong and elastic at the same time.

[0055] With the same dimensions as a traditional flat spring, the flat spring 1 according to the invention has a significantly higher elastic force.

[0056] Therefore, if a flat spring 1 having the same elastic force as a traditional flat spring is to be manufactured, the flat spring 1 according to the invention will certainly have significantly smaller dimensions.

[0057] Numerous variables influence the resistance, elasticity and elongation of spring 1, including:

[0058] - the thickness S of the material;

[0059] - the geometry of the central part 2 (spring length, spring width, number of undulations, amplitude of undulation A, radius of curvature of the curved section 22, etc.);

[0060] - the type of material; and

[0061] - the resistance of the raw material used.

[0062] In the spring according to the invention, the aforementioned variables can be modulated and adjusted in various ways.

[0063] Such a flat spring 1 can be used interchangeably in a tension, compression or torsion operating mode, without it being necessary to modify the structure of the spring.

[0064] Fig. 4A illustrates the use of the flat spring 1 in a tension operating mode in the direction of the arrows Fl.

[0065] Fig. 4B illustrates the use of the flat spring 1 in a compression operating mode in the direction of arrows F2.

[0066] Fig. 4C illustrates the use of the flat spring 1 in a torsional operating mode in the direction of arrows F3.

Claims

Demands

1. Flat spring (1) comprising a central part (2) disposed between two end parts (3a, 3b); characterized in that the central part (2) has a wavy shape extending over a plane, and said central part (2) has a flat, flat upper surface (20a) and a flat, flat lower surface (20b).

2. Flat spring (1) according to claim 1, characterized in that said central part (2) of the spring comprises a plurality of undulations (20).

3. Flat spring (1) according to claim 2, characterized in that each undulation (20) has a U-shape and comprises two straight sections (21) connected to each other by a curved section (22).

4. Flat spring (1) according to claim 3, characterized in that each straight section (21) of a corrugation (20) has a rectangular cross-section and each curved section (22) of a corrugation (20) has a radial rectangular cross-section.

5. Flat spring (1) according to claim 3 or 4, characterized in that said curved section (22) of each undulation (20) has a semi-circular shape.

6. Flat spring (1) according to any one of claims 2 to 5, characterized in that said undulations (20) are identical to each other.

7. Flat spring (1) according to any one of claims 3 to 6, characterized in that each straight section (21) of a corrugation (20) has a width (W), and between the two straight sections (21) of a corrugation (20) there is a distance (D) equal to the width (W) of the straight section (21).

8. Flat spring (1) according to any one of claims 3 to 6, characterized in that each straight section (21) of a wave (20) has a width (W), the central part (2) comprising the straight sections (21) and the curved sections (22) has a constant thickness (S), and the ratio between the width (W) of a straight section (21) and the thickness (S) of the central part (2) is in the range of 4 to 8.

9. Flat spring (1) according to any one of the preceding claims 1 to 8, characterized in that each end part 7 (3a, 3b) includes a plate (30) having the same thickness (S) as the central part (2).

10. Flat spring (1) according to claim 9, characterized in that said plate (30) of each end part (3a, 3b) has a hole (31).

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