Flexible layer support structure and retractable device

Abstract

The present invention discloses a flexible layer support structure and a rewinding device. The flexible layer support structure includes a first thin plate and a second thin plate that face each other and are arranged side by side, and a folding spring group that is clamped between the first thin plate and the second thin plate and is arranged side by side. The curved surface elastic pieces in the folding spring group are smoothly lapped and connected with the thin plates to form a hollow thin-walled elastic structure that can be superposed and bent, can be automatically straightened, and has a flat surface. The rewinding device includes a reel, a pressure roller, and a flexible layer support structure mounted on the reel. The flexible layer support structure is wound on the reel to realize the winding and unfolding of the entire flexible layer support structure. The flexible layer support structure of the present invention can be used as a support framework for flexible devices such as flexible screens, flexible solar cells, and thin film antennas, and has the advantages of light weight, high storage ratio, large unfolding area, simple rewinding, large load-bearing capacity, and not easy to damage.

Description

Technical Field

[0001] The present invention relates to a flexible layer support structure and a retractable device, which can be used for stable support after various flexible planes are unfolded. Background Art

[0002] A flexible screen can be curled and unfolded on a reel with a small enough radius without creases or plastic deformation, and it must be soft and thin enough. The existing flexible screen technology is already very advanced. The screen can be as thin as 0.01 mm, and the minimum curling radius can reach 1 mm. It is very soft and can flutter in the wind. However, such a thin and light screen needs to be equipped with a support skeleton with a certain stiffness that can be unfolded and retracted to maintain a stable shape for easy touch operation and viewing. Currently, the support skeletons of flexible screens mainly use devices such as rail-type telescopic slide bars, folding rods, and hinges as skeletons. However, there are many components, the structure is complex, the unfolding amplitude of the screen is limited, and the occupied space and self-weight are relatively large. Moreover, the skeleton and the screen are generally arranged separately and cannot protect and support the screen closely over the entire surface. The reel screen display device that unfolds like a scroll is still in the conceptual design stage and urgently needs an advanced support skeleton structure that can protect the entire surface, automatically flatten after stretching, be lightweight and have high stiffness, and can be retracted smoothly.

[0003] The Chinese patent application with the application number 201310752951.X discloses a retractable thin-walled support structure for supporting a retractable flexible screen after unfolding. The solution of this patent application combines a first elastic convex thin-walled member and a second elastic convex thin-walled member to form a thin-walled structure with a relatively large bending moment of inertia and torsional moment of inertia. The elastic resilience of the first elastic convex thin-walled member and the second elastic convex thin-walled member themselves bears a relatively large bending moment and axial pressure to maintain the stability of the retractable flexible screen loaded thereon after unfolding, and at the same time, it can be retracted after the first elastic convex thin-walled member and the second elastic convex thin-walled member are elastically overlapped.

[0004] The thin-walled support structure of the above solution can realize the unfolding and retraction of the flexible plane, but there are the following problems: (1) Both outer surfaces of the thin-walled structure are arc surfaces protruding outwards, which is not conducive to reliable fixation with the carried flexible plane;

[0005] (2) In the state of flexible planar expansion, both outer surfaces of the thin-walled structure formed by the first elastic convex thin-walled member and the second elastic convex thin-walled member under their own elastic actions are arc-shaped surfaces protruding outward. Since the middle parts of the first elastic convex thin-walled member and the second elastic convex thin-walled member bulge outward, the combined parts on the two lateral sides of the thin-walled structure move towards each other. In this state, the lateral dimension of the thin-walled structure is smaller than the lateral dimension after the first elastic convex thin-walled member and the second elastic convex thin-walled member are flattened; in the state of winding the flexible screen together with the thin-walled structure, the first elastic convex thin-walled member and the second elastic convex thin-walled member are overlapped and flattened, and the combined parts on the two lateral sides of the thin-walled structure move outward. The lateral dimension of the thin-walled structure expands in the lateral direction to be equal to the lateral dimension after the first elastic convex thin-walled member and the second elastic convex thin-walled member are flattened. It can be seen that the lateral dimension of this thin-walled support structure will change in the states of expansion and winding. When multiple groups of thin-walled support structures are carried on the same flexible plane, the winding and unwinding operations will cause pulling at the combined positions of different thin-walled support structures and the flexible plane, affecting the fixation of the flexible plane on the thin-walled support structure.

[0006] (3) The interlayer shear force of the superposed and bent structures of the first elastic convex thin-walled member and the second elastic convex thin-walled member can only be transferred transversely within the plane of the two thin-walled members and is offset from each other at their joint parts. Since the thin-walled members in the structure are relatively thin, after the structure is bent, the closer to the joint part, the greater the shear stress, and the distribution is uneven, the local deformation is inconsistent, and the longitudinal deformation accumulates. Therefore, in this state where the shear force transmission path is relatively long, it is easy to yield or have excessive deformation and out-of-plane instability, and it is very difficult to make the superposed structure fit the scroll and curl. Especially when the width of the structure is large and the curling radius is small, the interlayer shear force of the structure will be greater, and it is more likely to have out-of-plane deformation or instability. The elastic members of each layer cannot be closely superposed. Even when bent and wound within the elastic range, they cannot be evenly fitted and wound on the scroll, easily causing uneven deformation of the flexible device and resulting in damage. Summary of the Invention

[0007] The technical problem solved by the present invention is: aiming at the above problems existing in the above-mentioned rollable thin-walled support structure, to provide a flexible layer support structure and a rewinding device with stable and reliable structures.

[0008] The present invention is implemented by adopting the following technical solutions:

[0009] The flexible layer support structure comprises at least two stacked thin plates and at least two folding springs sandwiched in parallel between the thin plates; the folding springs are arranged in parallel along a first direction of the thin plates, and each of the folding springs is a long corrugated compression spring formed by a series of an even number of curved elastic sheets extending in a second direction of the thin plates, and the folding springs have an elastic tendency to stretch the thin plates on both sides, and after the folding springs are compressed, all the curved elastic sheets are stacked with the thin plates into a layered structure; the outer edges of the curved elastic sheets at the two outer ends of the folding springs are smoothly overlapped with the adjacent thin plates, and a hollow thin-walled layer structure with bending stiffness is formed between the folding springs and the thin plates; when the thin plates are subjected to a sufficiently large stacking pressure in the deformation direction of the folding springs, all the thin plates and the folding springs of the flexible layer support structure are stacked into a bendable or curled stacked flexible layer structure, and after the stacking pressure is removed, the folding springs quickly and elastically stretch the thin plates to return to their original state.

[0010] In the above-mentioned flexible layer support structure, further, the thin plate includes a first thin plate and a second thin plate; all folding springs are distributed in the projection area where the first thin plate and the second thin plate are overlapped; the connection positions between the curved elastic sheets and the first thin plate and the second thin plate are fixed joints, and the connection positions between the curved elastic sheets in the projection area of ​​the first thin plate and the second thin plate are free joints, and the free joints translate along the first direction of the thin plate during the folding and stretching of the folding springs, the free joints of adjacent folding springs are arranged facing or in opposite directions, and gaps are provided between the free joints arranged facing each other for the free joints to translate.

[0011] In the above-mentioned flexible layer support structure, further, the sum of the width of all the curved elastic sheets in the same layer after flattening and the width of the gap in the joint is not greater than the width of the thin plate connected thereto, and the width of the gap is not less than the sum of the maximum strokes of the free joints on both sides thereof. Moreover, as long as the sum of the width of all the curved elastic sheets in the same layer after flattening and the width of the gap in the joint is equal to the width of the thin plate connected thereto, even if there is inconsistency in the width of the first thin plate and the second thin plate, or there is inconsistency in the initial thickness of the folding spring, so that the two thin plates have a small angle and are not completely parallel, or there is inconsistency in the width of the two curved elastic sheets in the folding spring after flattening, and the two curved elastic sheets are not symmetrical along the overlapping surface in the natural state, etc., the flexible layer support structure can still achieve overlapping and flattening. However, try to arrange the thin plates, folding springs and curved elastic sheets in the structure symmetrically, and symmetrical arrangement can be considered as a preferred option.

[0012] In the above-mentioned flexible layer support structure, further, the cross section of the curved spring sheet in the first direction is a smooth curve, and the two side ends smoothly transition to a tangent connection at the fixed joint or the free joint to form a folded spring with at least one V-shaped opening.

[0013] In the above flexible layer support structure, further, side-sealing folding springs are fixedly coupled to two side edges of the first thin plate and the second thin plate along the second direction, and the side-sealing folding springs on the same side of the first thin plate and the second thin plate extend outward and are fixedly coupled to seal the two side seams between the first thin plate and the second thin plate.

[0014] In the above flexible layer support structure, further, the thin plate, the folding spring and the side-sealing folding spring are made of one or more of a metal material, a polymer material, a fiber-reinforced polymer, a wire skeleton, and a porous thin plate.

[0015] In the above flexible layer support structure, further, the fixed coupling methods of the fixed coupling part and the free coupling part include bonding, welding, fusion welding, press fitting or riveting.

[0016] In the above flexible layer support structure, further, the curvature of any point after the cross section of the curved surface elastic sheet and the thin plate are bent or curled satisfies the following relational expression:

[0017]

[0018] where: t is the thickness of the curved surface elastic sheet or the thin plate;

[0019] E is the elastic modulus of the curved surface elastic sheet or the thin plate;

[0020] ρ is the radius of curvature of the neutral layer of a single curved surface elastic sheet or thin plate;

[0021] σ e is the elastic limit value of the curved surface elastic sheet or the thin plate.

[0022] In the above flexible layer support structure, further, more than two sets of folding spring groups connected in series are clamped between the first thin plate and the second thin plate, and an intermediate layer is added between the folding springs.

[0023] In a preferred embodiment of the flexible layer support structure of the present invention, at least two sets of the thin plates are assembled along the first direction, and stepped structures that fit into each other are provided on the assembled side edges of the thin plates.

[0024] In the above flexible layer support structure, further, the thickness of the thin plate and the curved surface elastic sheet is 0.001 to 2 mm, preferably 0.01 to 0.5 mm.

[0025] In the above flexible layer support structure, further, concave-convex structures that engage with each other in the superposed state of the flexible layer support structure are provided on the surfaces of the curved surface elastic sheet of the folding spring, the first thin plate and the second thin plate.

[0026] In the above flexible layer support structure, further, the concave-convex structure includes a concave-convex stripe structure arranged along the first direction or the second direction, or a concave-convex embossed structure with a surface distribution, or a plurality of shear keys and key grooves / holes.

[0027] The present invention also discloses a rewinding device, which includes a reel, a pressure roller, and a flexible layer wound on the reel. The flexible layer adopts the flexible layer support structure of the present invention as described above; a gap with a width smaller than the expanded thickness of the flexible layer is provided between the pressure roller and the reel or between the pressure rollers. The flexible layer passes through the gap and is wound on the reel. During the winding process of the flexible layer, after being squeezed by the pressure roller and the reel, the folding springs and thin plates of the flexible layer support structure are superposed into a layered structure and wound on the reel; during the unwinding process of the flexible layer support structure, for the part of the structure that leaves the pressure roller and the reel, the folding springs expand the thin plates and restore to a rigid, flat, hollow thin-walled layer structure.

[0028] The flexible layer support structure of the present invention encloses an elastic structure with a large bending moment of inertia and torsional moment of inertia and capable of being superposed and bent between the curved elastic sheets of the folding springs and the thin plates. When a sufficient large superposition pressure is applied to the surface of the thin plate of the structure, each curved elastic sheet flattens into a superposed thin sheet structure that can be bent or curled along the superposition surface. When the superposition pressure on the structure is removed, the structure quickly restores to the original hollow thin-walled elastic structure under the action of the self-elasticity of the curved elastic sheets. The support concave layer formed by the curved elastic sheets after the folding springs are restored provides sufficient support stiffness and protection for the flexible layer support structure. The elastic deformation of the folding springs all occurs within the space between the thin plates and will not cause deformation and displacement of the surface of the thin plates of the flexible layer support structure.

[0029] One end of the flexible layer support structure of the present invention in one direction is connected to the reel. The first thin plate and the second thin plate of the flexible layer support structure are superposed and wound by pressing with the pressure roller. When in use, the flexible layer support structure is unwound and unfolded from the reel. The part that leaves the reel automatically restores to the natural state of a flat hollow thin-walled structure with a greater stiffness through the elastic recovery of the folding springs. It has a very large storage ratio. At the same time, the unfolded flexible layer support structure can withstand a sufficient large bending moment in the normal directions of the two thin plate surfaces. The flexible layer support structure in the natural state has higher bending resistance and support stiffness. In addition, between the curved elastic sheets and the thin plates and between the curved elastic sheets, the mechanical bite and friction are increased through the mutually engaged concave-convex structures in the superposed state, resisting the interlayer shear force during the bending or curling process of the flexible layer support structure, avoiding relative slippage between the layers during the winding process, and improving the curling or bending performance of the flexible layer support structure in the superposed state.

[0030] Taking the flexible layer support structure of thin plates and folding springs as the basic unit, on the basis of ensuring local stiffness and not changing the rollable performance, multiple basic units are spliced horizontally to form a porous rollable support structure panel with a larger area, which is convenient for carrying flexible devices such as flexible screens, flexible solar cells, and satellite antennas, and realizes the extended paving of large-area flexible screens. When the flexible device needs to be used, the flexible layer support structure panel and the flexible device are pulled out from the reel or taken out from the reel together. The elastic restoring force of the flexible layer support structure panel itself drives the flexible device to automatically flatten, providing sufficient support stiffness and overall protection for the flexible device. When the flexible device is no longer in use, the flexible device and the flexible layer support structure are rolled back onto the reel together. Therefore, the flexible device using this structure occupies less space and is convenient for storage.

[0031] In summary, the technical solution proposed by the present invention effectively solves the problems existing in the existing flexible screen support framework, such as having more components, complex structure, limited screen unfolding amplitude, large occupied space and self-weight. The present invention can realize the co-rolling and unfolding of the support structure and the flexible device, and is a support framework structure that can provide overall protection, automatically flatten after unfolding, be lightweight and highly rigid, and can be rolled up and down freely, and has good application prospects in flexible devices such as reel screens, flexible solar cells, and satellite antennas.

[0032] The following further illustrates the present invention in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0033] Figure 1 It is a schematic exploded view of the flexible layer support structure in Embodiment 1.

[0034] Figure 2a 、 2b They are respectively three-dimensional views of the flexible layer support structure in the natural state and the superposed state of the thin plate in Embodiment 1.

[0035] Figure 3 It is a mechanism diagram of the mutual conversion between the natural state and the superposed state of the flexible layer support structure in Embodiment 1.

[0036] Figure 4a 、 4b They are respectively cross-sectional views of the flexible layer support structure in the natural state and the superposed state in Embodiment 1.

[0037] Figure 5 It is a schematic diagram of the device in the rolled-up or unfolded state of the flexible layer support structure in Embodiment 1.

[0038] Figure 6a 、 6b They are respectively schematic diagrams of the out-of-plane bending type and in-plane bending type flexible layer support structures in Embodiment 1.

[0039] Figure 7a , 7b They are respectively cross-sectional views of a flexible layer support structure in Example 2 in the natural state and the superposed state.

[0040] Figure 8a , 8b They are respectively cross-sectional views of another flexible layer support structure in Example 2 in the natural state and the superposed state.

[0041] Figure 9a , 9b They are respectively cross-sectional views of the flexible layer support structure panel in Example 3 in the natural state and the superposed state.

[0042] Figure 10 It is a schematic diagram of the device of the flexible layer support structure panel in Example 3 in the winding or unwinding state.

[0043] Figure 11a , 11b They are respectively cross-sectional views of the flexible layer support structure panel in Example 4 in the natural state and the superposed state.

[0044] Figure 12a , 12b They are respectively axonometric views of the flexible layer support structure in Example 5 in the natural state and the superposed state.

[0045] Figure 13a , 13b They are respectively A-A longitudinal sectional views of the flexible layer support structure in Example 5 in the natural state and the superposed state.

[0046] Figure 14a , 14b They are respectively B-B longitudinal sectional views of the flexible layer support structure in Example 5 in the natural state and the superposed state.

[0047] Figure 15a , 15b They are respectively C-C longitudinal sectional views of the flexible layer support structure in Example 5 in the natural state and the superposed state.

[0048] Figure 16a , 16b They are respectively axonometric views of the flexible layer support structure in Example 6 in the natural state and the superposed state.

[0049] Figure 17a , 17b They are respectively A-A longitudinal sectional views of the flexible layer support structure in Example 6 in the natural state and the superposed state.

[0050] Figure 18a , 18bThey are respectively the B-B longitudinal sectional views of the flexible layer support structure in Example 6 in the natural state and the superposed state.

[0051] Figure 19a 、 19b They are respectively the C-C longitudinal sectional views of the flexible layer support structure in Example 6 in the natural state and the superposed state.

[0052] Figure 20a 、 20b They are respectively the cross-sectional views of the flexible layer support structure in Example 7 in the natural state and the superposed state.

[0053] Figure 21 It is the cross-sectional view of the flexible layer support structure in Example 8 in the natural state.

[0054] Figure 22 It is the overall effect diagram of multiple flexible layer support structures in Example 8 spliced horizontally.

[0055] Reference numerals in the figures: 1 - first thin plate, 2 - second thin plate, 3 - intermediate layer, 5 - first folding spring, 6 - second folding spring, 7 - gap, 9 - strip-shaped flexible layer support structure, 10 - panel flexible layer support structure;

[0056] 11 - first curved elastic sheet, 12 - second curved elastic sheet, 13 - third curved elastic sheet, 14 - fourth curved elastic sheet, 15 - fifth curved elastic sheet, 16 - sixth curved elastic sheet, 17 - seventh curved elastic sheet, 18 - eighth curved elastic sheet, 19 - side-sealing folding spring;

[0057] 21 - first joint part, 22 - second joint part, 23 - third joint part, 24 - fourth joint part, 25 - fifth joint part, 26 - sixth joint part;

[0058] 31 - convex tooth, 32 - tooth groove, 33 - shear key, 34 - key groove, 35 - key hole;

[0059] 41 - reel, 42 - pressure roller;

[0060] 51 - first lapping step, 52 - second lapping step, 53 - third lapping step, 54 - fourth lapping step; Detailed implementation manners

[0061] Example 1

[0062] See Figure 1 and Figure 2a, A flexible layer support structure in the illustration is a basic solution of the present invention. The strip-shaped flexible layer support structure 9 in this embodiment is a long strip-shaped foldable hollow thin-walled structure, including two thin plates of equal size, arranged parallel and facing each other, and two identical V-shaped folding springs clamped between them. Both the thin plates and the folding springs are elastic thin-walled components. The shape of the thin plate is a long rectangle, and the folding spring is a long strip-shaped foldable sheet compression spring. The direction of spring compression deformation is the vertical direction of the thin plate, and the deformation amount is the distance between the inner surfaces of the two thin plates. The two folding springs are symmetrically arranged in the transverse direction of the structure and both openings face outwards. There is a certain distance between them and they are not directly connected to each other, but are connected by two thin plates. Both of them can be folded inwards without interfering with each other.

[0063] To more accurately describe the strip-shaped flexible layer support structure 9 of this embodiment, a three-dimensional space coordinate system is established in the figure based on the longitudinal, transverse, and thickness directions of the strip-shaped flexible layer support structure 9. Among them, the x-axis is set as the transverse direction (the first direction) of the strip-shaped flexible layer support structure 9, the y-axis is set as the longitudinal direction (the second direction) of the strip-shaped flexible layer support structure 9, and the z-axis is set as the height direction (the third direction) of the strip-shaped flexible layer support structure 9.

[0064] Specifically, as Figure 2a and Figure 2b shown, the two thin plates in the flexible layer support structure of this embodiment are respectively set as the first thin plate 1 and the second thin plate 2, and the two folding springs are respectively set as the first folding spring 5 and the second folding spring 6. The first folding spring 5 and the second folding spring 6 are arranged side by side in the transverse direction of the strip-shaped flexible layer support structure 9. Both the first folding spring 5 and the second folding spring 6 are sheet compression spring structures that continuously extend along the longitudinal direction of the strip-shaped flexible layer support structure 9. The wing edges of the first folding spring 5 are respectively flush with and tangent to the left inner surface edges of the two thin plates. Similarly, the wing edges of the second folding spring 6 are respectively flush with and tangent to the right inner surface edges of the two thin plates. These four thin-walled components are sequentially connected to form a flexible layer hollow thin-walled elastic structure with parallel upper and lower surfaces and foldable sides.

[0065] As Figure 2a shown, when the strip-shaped flexible layer support structure 9 is not subjected to external forces, the structure is in a natural state without deformation; when the structure is compressed by external forces to fold the folding springs to achieve the superposition between the first thin plate 1 and the second thin plate 2, that is, the structure is compressed to the superposed state, as Figure 2b shown; when the external forces on the structure are removed, the folding springs elastically support the two thin plates apart, and the structure elastically returns to its original shape, that is, the natural state. The structure can be converted between the natural state and the superposed state as Figure 3As shown, it can be seen that in the natural state or the superposed state, the projections of the first folding spring 5 and the second folding spring 6 on the first thin plate 1 or the second thin plate 2 do not exceed the outer contours of the two thin plate surfaces, and there is no overlapping area in the projections of the two folding springs on the thin plate surface. That is, both folding springs are in the projection areas of the first thin plate 1 and the second thin plate 2 whether in the compressed state or the elastic expansion state, without causing changes in the appearance dimensions of the strip-shaped flexible layer support structure 9, ensuring comprehensive support for the entire flexible device.

[0066] The cross-section of the strip-shaped flexible layer support structure 9 in the natural state is as Figure 4a shown. The specific structure of the two folding springs between the first thin plate 1 and the second thin plate 2 is as follows:

[0067] The first folding spring 5 includes a first curved elastic sheet 11 and a third curved elastic sheet 13 with the same thickness. Both the first curved elastic sheet 11 and the third curved elastic sheet 13 are strip-shaped elastic sheets with the same longitudinal length as the strip-shaped flexible layer support structure 9. The center line of the cross-section of the first curved elastic sheet 11 is a smooth reverse S shape, and the center line of the cross-section of the third curved elastic sheet 13 is a smooth S shape. The two curved elastic sheets are symmetrically arranged with the xy plane (the central superposed plane) as the symmetry plane. One side edge in the transverse direction of the two is fixedly overlapped with the central superposed plane as the cutting plane to form a fifth joint 25, forming a V-shaped folding spring with the opening facing left; the other side edge in the transverse direction of the two (the free side edge of the V-shaped folding spring) is aligned and tangentially overlapped with the left side edges of the first thin plate 1 and the second thin plate 2, respectively forming a first joint 21 and a third joint 23. The joint surfaces of the two joints are respectively with the lower surface of the first thin plate 1 and the upper surface of the second thin plate 2 as the cutting planes.

[0068] Similarly, the second folding spring 6 includes a first curved elastic sheet 12 and a fourth curved elastic sheet 14 with the same thickness. The center line of the cross-section of the second curved elastic sheet 12 is a smooth S shape, and the center line of the cross-section of the fourth curved elastic sheet 14 is a smooth reverse S shape. The two curved elastic sheets are symmetrically arranged with the central superposed plane as the symmetry plane. One side edge in the transverse direction of the two is fixedly overlapped with the central superposed plane as the cutting plane to form a sixth joint 26, forming a V-shaped folding spring with the opening facing right; the other side edge in the transverse direction of the two is aligned and tangentially overlapped with the right side edges of the first thin plate 1 and the second thin plate 2, respectively forming a second joint 22 and a fourth joint 24. The joint surfaces of the two joints are respectively with the lower surface of the first thin plate 1 and the upper surface of the second thin plate 2 as the cutting planes.

[0069] The center line of the cross-section of the curved surface elastic sheet is formed by tangentially connecting a convex circular curve and a concave circular curve. The entire cross-section center line is a smooth curve in the shape of an S or reverse S without sharp corners, and the combined ends on both sides are set to be tangential transitions. In addition to using a circular curve with a constant radius of curvature, the smooth curve can also select smooth curves such as a parabola or a transition curve with a changing radius of curvature, and a straight line segment tangent to it can be inserted in between. However, the entire center line must be a smooth curve without sharp corners to avoid plastic deformation after the curved surface elastic sheet is flattened.

[0070] During the lamination process of the strip-shaped flexible layer support structure 9 in this embodiment, the first joint 21 and the second joint 22 connected to both sides of the thin plate, and the third joint 23 and the fourth joint 24 are fixed to the thin plate, and the distance between them remains unchanged, which are fixed joints. The fifth joint 25 and the sixth joint 26 in the folding spring move closer to each other in the transverse direction of the structure, and the width of the gap 7 between them gradually becomes smaller, while there is no relative displacement in the height direction of the structure. After removing the lamination force, the two return to the original gap 7. Since the fifth joint 25 and the sixth joint 26 can move relative to each other in the transverse direction of the structure during the lamination process of the folding spring, they are also called free joints.

[0071] The cross-section of the strip-shaped flexible layer support structure 9 in the laminated state is as Figure 4b shown. The actual width of each curved surface elastic sheet in the transverse direction after being flattened does not exceed half of the width of the thin plate connected to it, or the sum of the widths of two curved surface elastic sheets connected to the same thin plate after being flattened is not greater than the width of the thin plate, that is, the width of the gap 7 is not less than the sum of the maximum strokes of the fifth joint 25 and the sixth joint 26 on both sides of it; or the sum of the widths of all the curved surface elastic sheets in the same layer after being flattened + the width of all the joint gaps = the width of the thin plate corresponding to the connection, and the structure can be laminated. When the width of the gap 7 is equal to the sum of the strokes of the two free joints, after the structure is laminated, the two free joints just abut against each other, as shown in Figure 4b shown. However, the width of the gap 7 can be appropriately greater than the sum of the strokes of the two free joints. In this way, after the folding spring is compressed in place, there will still be a certain space between the fifth joint 25 and the sixth joint 26, which can be used to accommodate dust and impurities between the thin plates, avoiding damage to the thin plates caused by the direct imprint of dust and impurities.

[0072] In the specific application of this embodiment, the curvature of any point on the cross-section of the curved surface elastic sheet and the bent or curled thin plate satisfies the following relational expression:

[0073]

[0074] where: t is the thickness of the curved surface elastic sheet or the thin plate;

[0075] E is the elastic modulus of the curved surface elastic sheet or the thin plate;

[0076] ρ is the radius of curvature of the neutral layer of a single curved elastic sheet or thin plate;

[0077] σ e is the elastic limit value of the curved elastic sheet or thin plate.

[0078] Based on the above curvature expression, the initial curvature of the thin-walled part or the deformed curve is optimized, so as to reduce the probability of plastic deformation of the thin-walled part. The joints between all the curved elastic sheets and the thin plates, and the joints between the curved elastic sheets and the curved elastic sheets are all set to be smoothly tangent joints, so as to avoid excessive stress at the joints during the structural lamination bending or curling process, resulting in inconsistent local deformation or tearing damage.

[0079] In the strip-shaped flexible layer support structure 9 of this embodiment, thin-walled parts such as curved elastic sheets or thin plates are made of high-elasticity metals, high-elasticity polymers, fiber-reinforced polymers or wire-frame-reinforced polymer materials. The metal materials can be alloy high-elasticity and high-strength materials such as stainless steel, shape memory alloy, and titanium alloy; the metal wires are woven into the frame of the curved elastic sheet or porous thin plate; high-elasticity and low-plasticity polymers such as PEEK, TPE, PU, PET, and rubber, and fiber-reinforced polymers such as glass fiber, carbon fiber, and metal fiber-reinforced high-elasticity polymers.

[0080] The fixed connection methods at the joints between the curved elastic sheet and the thin plate, and between the curved elastic sheet and the curved elastic sheet include bonding, welding, fusing, crimping or riveting. For bonding with adhesives, it is best to use adhesives with high strength and a modulus similar to that of the thin-walled parts to ensure the bonding quality; for metal materials, welding or riveting methods can be used; for materials such as high-elasticity polymers and fiber-reinforced polymers, bonding with adhesives or high-temperature fusion can be used. In this embodiment, high-temperature fusion connection is adopted, and all joints connect the curved elastic sheets with each other and the curved elastic sheet with the thin plate integrally.

[0081] See Figure 5 , this embodiment also discloses a rewinding device using the above strip-shaped flexible layer support structure 9, including a reel 41, a pressure roller 42, and the strip-shaped flexible layer support structure 9 wound on the reel 41. The flexible layer component using the strip-shaped flexible layer support structure 9 realizes the winding and unwinding of the entire structure by winding on the reel 41.

[0082] During the winding process, the flexible layer component of the strip-like flexible layer support structure 9 passes through the gap between the pressure roller 42 and the reel 41 and is wound on the reel 41. The gap formed between the circumferential surface of the pressure roller 42 and the wound circumferential surface of the reel 41 corresponds to the thickness of the strip-like flexible layer support structure 9 in the overlapped state, which is smaller than the thickness of the strip-like flexible layer support structure 9 in the natural state. The structural part of the flexible layer component close to the reel 41 is squeezed by the pressure roller 42, and the folding spring is compressed, and the two thin plates gradually approach each other. The closer the structural part is to the reel 41 and the pressure roller 42, the smaller the height. Finally, under the squeezing of the reel 41 and the pressure roller 42, the thin plate and the folding spring of the structural part are pressed into a overlapping state. At this time, the cross-sectional bending inertia moment of the structural part around the x-axis is the smallest, and it becomes very soft, so that it can be curled on the reel 41 with the designed minimum radius, and the thinner the thin-walled part, the easier it is to curl.

[0083] The reel 41 is the winding shaft of the flexible layer, and the pressure roller 42 pre-presses the flexible layer before it is wound onto the reel 41. The pressure roller 42 and the reel 41 can form a gap for pre-pressing the flexible layer, or two sets of pressure rollers 42 arranged in pairs can be used to form a pre-pressed gap alone.

[0084] During the unwinding process, the strip-shaped flexible layer support structure 9 leaves the structural part of the reel 41 and the pressure roller 42, and the elastic force of the folding spring opens the upper and lower thin plates, and the structure automatically straightens and recovers to a natural state with a certain rigidity, that is, a hollow thin-walled structure with flat upper and lower surfaces. At this time, the structural part restored to the natural state can withstand the bending moment around the transverse x-axis and the axial pressure along the longitudinal y-axis. Even if the structure exceeds the ultimate bearing capacity of the structure under the action of external loads, the folding spring compresses and overlaps to make the strip-shaped flexible layer support structure 9 suddenly unstable as a whole and overlaps and bends, so as to release the influence of external loads and avoid structural damage.

[0085] In order to enable the curled or bent strip-shaped flexible layer support structure 9 to elastically recover to its original uncurled natural shape, that is, the structure to deform within the elastic range, the radius of the reel 41 should be greater than or equal to the minimum design radius of the structure. The curling radius should ensure that each part of the curled structure is in an elastic deformation state, otherwise the structure will undergo plastic deformation or damage and will not be able to recover to its original shape.

[0086] When the retractable device of this embodiment is in use, after the band-shaped flexible layer support structure 9 in the curled and folded state is stretched out from the reel 41 or taken out from the turntable and unfolded, the elastic restoring force of the folding spring in the structure part leaving the reel 41 automatically straightens and flattens into a flat surface structure with large bending and torsional inertia moments, which can withstand large bending moments and axial pressures without becoming unstable or damaged. When the structure is used up, it is rolled back onto the reel 41, so the retractable device occupies less space and is easy to store.

[0087] The longitudinal direction of the strip-shaped flexible layer support structure 9 in this embodiment is a straight shape with equal height, and this structure is applicable to flexible structures such as flat screens. Similarly, by adjusting the shapes of the folding springs and the thin plates, an arc-shaped bent in the plane or an arc-shaped bent outside the plane can be constructed to carry and meet the requirements of different flexible devices. Figure 6a It indicates that the bending direction of the strip-shaped flexible layer support structure 9 is bent in the xz plane, and this structure is suitable for flexible devices such as curved screens; Figure 6b It indicates that the bending direction of the strip-shaped flexible layer support structure 9 is bent in the xy plane, and this structure is suitable for flexible devices such as fan-shaped screens.

[0088] Embodiment 2

[0089] Refer to Figure 7a 、 7b As shown in [references], a strip-shaped flexible layer support structure 9 in the figure is another specific implementation of the present invention. This embodiment is based on Embodiment 1. The difference is that the first folding spring 5 and the second folding spring 6 in this embodiment are respectively formed by connecting two V-shaped folding springs in series to form a spring group. That is, each folding spring group is composed of 4 curved elastic sheets connected in series along the height direction of the flexible layer, and its compression deformation direction is also the height direction of the structure. For the series connection, the deformation of the spring group is the sum of the deformation amounts of all single springs, and the load is the same as that of a single spring; for the parallel connection, the deformation of the spring group is the same as that of a single spring, and the load is the sum of the loads of all single springs.

[0090] Further described, in this embodiment, the four outer side edges of the first curved surface elastic sheet 11, the second curved surface elastic sheet 12, the third curved surface elastic sheet 13, and the fourth curved surface elastic sheet 14 in the first folding spring 5 are respectively fixedly combined with the four side edges of the first thin plate 1 and the second thin plate 2 to form a fixed combination part. A fifth curved surface elastic sheet 15 and a seventh curved surface elastic sheet 17 are added between the first curved surface elastic sheet 11 and the third curved surface elastic sheet 13 of the first folding spring 5; a sixth curved surface elastic sheet 16 and an eighth curved surface elastic sheet 18 are added between the second curved surface elastic sheet 12 and the fourth curved surface elastic sheet 14 of the second folding spring 6. One side edge of the fifth curved surface elastic sheet 15 and one side edge of the seventh curved surface elastic sheet 17 are respectively fixedly combined with the other side edge of the first curved surface elastic sheet 11 and the other side edge of the third curved surface elastic sheet 13 to form two free combination parts, and the other side edges of the fifth curved surface elastic sheet 15 and the seventh curved surface elastic sheet 17 are combined with each other to form a free combination part; one side edge of the sixth curved surface elastic sheet 16 and one side edge of the eighth curved surface elastic sheet 18 are respectively fixedly combined with the other side edge of the second curved surface elastic sheet 12 and the other side edge of the fourth curved surface elastic sheet 14 to form two free combination parts, and the other side edges of the sixth curved surface elastic sheet 16 and the eighth curved surface elastic sheet 18 are combined with each other to form a free combination part. In the folding spring arrangement of this solution, along the height direction of the strip-shaped flexible layer support structure 9, by increasing the number of V-shaped folding springs or curved surface elastic sheets, the structural cross-section height is increased without changing the spring load, and the bending stiffness of the structure is increased.

[0091] Further, in this embodiment, considering that the curved surface elastic sheets located in the middle of the two groups of folding springs are not directly connected to the thin plates, the free combination parts between the fifth curved surface elastic sheet 15 and the seventh curved surface elastic sheet 17 and the free combination parts between the sixth curved surface elastic sheet 16 and the eighth curved surface elastic sheet 18 are prone to instability and displacement to both sides during the folding and compression process. An intermediate layer 3 parallel to the first thin plate and the second thin plate is added between the two juxtaposed folding spring groups, as Figure 8a , 8b shown. The free combination parts between the fifth curved surface elastic sheet 15 and the seventh curved surface elastic sheet 17 and the free combination parts between the sixth curved surface elastic sheet 16 and the eighth curved surface elastic sheet 18 are respectively fixedly combined with the two side edges of the intermediate layer 3, and these two free combination parts are transformed into fixed combination parts that are relatively fixed in the lateral direction of the intermediate layer and the thin plates. Therefore, adding an intermediate layer between the folding spring groups is equivalent to forming a multi-layer thin plate - folding spring group structure, increasing the structural support stability of the multi-layer folding spring groups.

[0092] In this embodiment, the number of curved surface elastic sheets is increased in the deformation direction of the folding spring. Without changing the load conditions of the folding spring, the deformation amount of the folding spring and the height of the structure are increased, and the bending resistance performance and stiffness of the structure are increased.

[0093] Embodiment III

[0094] Refer to Figure 9a and 9b , in which a panel flexible layer support structure 10 in the figure is another specific implementation of the present invention. Based on the strip-shaped flexible layer support structure 9 in Embodiment I, more folding springs arranged side by side are clamped between wider thin plate groups in the transverse direction of the structure to form a laterally wider panel flexible layer support 10. The longitudinal dimension of its structure can be adapted by adjusting the longitudinal length of the curved elastic sheet, and it can be used to form the flexible layer support of the panel.

[0095] Refer to Figure 10 , this embodiment also discloses a winding device for the panel flexible layer support structure 10, including a reel 41, a pressure roller 42 and a panel flexible layer. The panel flexible layer adopts the panel flexible layer support structure 10 of this embodiment, including stacked first thin plates 1 and second thin plates 2 and a number of folding springs arranged in pairs and oppositely clamped between the first thin plates 1 and the second thin plates 2 in the transverse direction of the structure. The axial length of the reel 41 matches the width of the panel flexible layer support structure 10, and the panel flexible layer support structure 10 is wound on the reel 41 to realize the winding and unfolding of the entire support structure. The connection manner of each folding spring to the thin plate and the arrangement manner of the pressure roller 42 and the reel 41 can refer to Embodiment I and Embodiment II.

[0096] Embodiment IV

[0097] Refer to Figure 11a and 11b , in which a panel flexible layer support structure 10 in the figure is another specific implementation of the present invention. Based on the panel flexible layer support structure 10 in Embodiment III, side-sealing folding springs 19 are respectively fixedly combined on two side edges of the first thin plate 1 and the second thin plate 2 of the panel flexible layer support structure 10 along the second direction. The side-sealing folding springs 19 on the same side of the first thin plate 1 and the second thin plate 2 extend outward and are fixedly combined, so that when the panel flexible layer support structure 10 is in the expanded state of the first thin plate 1 and the second thin plate 2, the side seams formed between the curved elastic sheets combined on the side edges of the first thin plate 1 and the second thin plate 2 are sealed.

[0098] During the use of the panel flexible layer support structure 10 in the third embodiment, it is easy for debris to be trapped in the gap formed by the two pairs of curved elastic sheets on the outside. If it is not cleaned in time before rolling up, it will affect the bending performance of the structure. In this embodiment, a pair of side sealing folding springs 19 are added on both sides of the panel flexible layer support structure 10 to prevent debris from being trapped in the exposed gap of the panel flexible layer support structure 10. The structure of the side sealing folding spring 19 is the same as the folding spring structure between the first thin plate and the second thin plate, and is symmetrically arranged with the outermost folding spring between the adjacent first thin plate 1 and the second thin plate 2. While sealing the edge of the panel flexible layer support structure 10, it can also form an auxiliary support function for the side edges of the first thin plate 1 and the second thin plate 2. The side sealing folding spring 19 is completely extended out of the area outside the first thin plate 1 and the second thin plate 2, and is not flush with the surface of the thin plate when the first thin plate 1 and the second thin plate 2 are stretched out. Therefore, the area of ​​the side sealing folding spring 19 can be ignored as the surface layer of the panel flexible layer support structure 10.

[0099] The side seam folding spring 19 can also be arranged in the strip-shaped flexible layer supporting structure 9 of Embodiment 1 and Embodiment 2.

[0100] Embodiment 5

[0101] See also Figure 12a , 12b , a strip-shaped flexible layer support structure 9 shown in the figure is a further preferred solution of the first embodiment. In the first embodiment, the surfaces of the thin plate and the curved elastic sheet are both smooth surfaces. When the flexible layer support structure in the stacked state is bent or curled, the interlayer shear force is transmitted laterally in the plane of each curved elastic sheet. The transmission path is transmitted laterally from the center of the curved elastic sheet to the joint of the curved elastic sheet, and then transmitted laterally to the joint between the curved elastic sheet and the curved elastic sheet on the center stacked surface. Since the thin plate in the structure is relatively thin, the out-of-plane stability is very poor. After the structure is bent, the closer the curved elastic sheet and the joint are to the axis in the cross section of the structure, the greater the shear force, and the uneven distribution leads to inconsistent local deformation and accumulation of deformation along the longitudinal direction. Therefore, in the case of a long force transmission path, out-of-plane instability or excessive deformation and yielding are likely to occur, and it is difficult to make the stacked structure fit the scroll and curl, which greatly affects the bending performance of the structure. Especially when the width of the strip-shaped flexible layer support structure 9 is large and the curling radius is small, the interlayer shear force of the thin-walled parts will be greater, and out-of-plane deformation or instability will be more likely to occur. The curved elastic sheets of each layer cannot be tightly overlapped, and even if they are bent within the elastic range, they cannot be evenly fitted and rolled up on the reel 41, which can easily cause uneven deformation of the flexible equipment and lead to damage.

[0102] Based on the strip-shaped flexible layer support structure 9 in the above embodiment, on the curved surface elastic sheet, the first thin plate and the second thin plate of the folding spring, there are concave and convex structures that engage with each other in the superposed state of the strip-shaped flexible layer support structure 9. After the first thin plate and the second thin plate are superposed, the mechanical biting force and frictional force between layers are increased through the engaging concave and convex structures, canceling the interlayer staggered shear force when the entire structure is wound onto the reel.

[0103] In this embodiment, each part of the strip-shaped flexible layer support structure 9 is longitudinally cut along the yz plane parallel to the flexible layer, and the cutting positions are as Figure 12a , 12b shown. Due to the symmetry of the cross-section of the structure, only one side of the first folding spring is intercepted in this embodiment, and the structure of the second folding spring is symmetric to that of the first folding spring. A-A section is obtained by vertically cutting through the first joint 21 and the third joint 23, B-B section is obtained by vertically cutting on the structure between the first joint 21 and the fifth joint 25, and C-C section is obtained by vertically cutting through the fifth joint 25.

[0104] As Figure 13a and Figure 13b shown, in the longitudinal sectional view of part A of the first joint 21 and the third joint 23, on the contact surfaces where two groups of curved surface elastic sheets are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 extending to both end joints are alternately arranged along the longitudinal direction of the y-axis of the strip-shaped flexible layer support structure 9, and the convex teeth 31 and the tooth grooves 32 are staggeredly distributed on the surface of the curved surface elastic sheet respectively. After the first joint 21 and the third joint 23 are superposed in the strip-shaped flexible layer support structure 9, the convex teeth 31 and the tooth grooves 32 thereon engage with each other.

[0105] As Figure 14a and Figure 14b shown, similarly, in the longitudinal sectional view of part B, on the contact surfaces where the first thin plate 1 and the first curved surface elastic sheet 11 are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the strip-shaped flexible layer support structure 9; on the contact surfaces where the first curved surface elastic sheet 11 and the third curved surface elastic sheet 13 are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the strip-shaped flexible layer support structure 9; on the contact surfaces where the third curved surface elastic sheet 13 and the second thin plate 2 are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the strip-shaped flexible layer support structure 9. The convex teeth 31 and the tooth grooves 32 on the relative contact surfaces are staggeredly distributed respectively. In the superposed state, the opposite convex teeth 31 and tooth grooves 32 on each contact surface of the thin-walled parts in the strip-shaped flexible layer support structure 9 engage with each other;

[0106] As Figure 15a and Figure 15bAs shown, in the longitudinal sectional view of part C, on the contact surfaces where the first thin plate 1 and the fifth joint 25 are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure; on the contact surfaces where the second thin plate 2 and the fifth joint 25 are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure. The convex teeth 31 and tooth grooves 32 on the relative contact surfaces are respectively misaligned. In the superposed state, the opposite convex teeth 31 and tooth grooves 32 on the contact surfaces of each thin-walled part in the strip-shaped flexible layer support structure 9 are engaged with each other. Between each layer of thin-walled parts, the shear force between layers is resisted by the engagement of the convex teeth and tooth grooves on the contact surfaces. Since the shear force is directly transmitted perpendicular to the plate surface, the force transmission path is very short, the interlayer shear force is quickly offset, and both the shear stress and the non-uniform deformation will become smaller. Even for thin-walled parts with extremely small thickness and extremely large width, they can be bent and curled freely during superposition, and it is not easy to occur out-of-plane instability and abnormal curling.

[0107] Embodiment Six

[0108] See Figure 16a 、 16b , a strip-shaped flexible layer support structure 9 shown in the figure is another preferred implementation of the concave-convex structure in Embodiment Five. In this embodiment, continuous convex teeth 31 and tooth grooves 32 are also arranged along the longitudinal direction of the structure on the surfaces where two groups of curved elastic sheets are superposed relative to each other. Different from Embodiment Five, the layout of the convex teeth and tooth grooves on the surface of the curved elastic sheet or thin plate in this embodiment is not closely distributed, but there is a certain spacing, belonging to incomplete tooth patterns.

[0109] As Figure 17a and Figure 17b shown, in the longitudinal sectional view of part A of the relative first joint 21 and third joint 23, on the relative contact surfaces of the first joint 21 and third joint 23, continuous convex teeth 31 and tooth grooves 32 are distributed along the longitudinal direction of the structure. The convex teeth 31 and tooth grooves 32 are alternately distributed on the same surface, and the convex teeth 31 and tooth grooves 32 on the relative surfaces are engaged with each other in the superposed state. After the first joint 21 and third joint 23 are superposed with the flexible layer support structure, the convex teeth 31 and tooth grooves 32 thereon are engaged with each other.

[0110] As Figure 18a and Figure 18bAs shown, in the longitudinal sectional view of part B, on the surfaces of the first thin plate 1 and the first curved elastic sheet 11 that are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure; on the surfaces of the first curved elastic sheet 11 and the third curved elastic sheet 13 that are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure; on the surfaces of the third curved elastic sheet 13 and the second thin plate 2 that are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure. The convex teeth 31 and the tooth grooves 32 are alternately distributed on the same surface and there is a certain distance between them, and the convex teeth 31 and the tooth grooves 32 on the relative surfaces are engaged with each other in the superposed state.

[0111] As Figure 19a and Figure 19b shown, in the longitudinal sectional view of part C, on the surfaces of the first thin plate 1 and the fifth joint part 25 that are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure; on the surfaces of the second thin plate 2 and the fifth joint part 25 that are superposed relative to each other, continuous convex teeth 31 and tooth grooves 32 are alternately distributed along the longitudinal direction of the structure. The convex teeth 31 and the tooth grooves 32 are alternately distributed on the same surface, and the convex teeth 31 and the tooth grooves 32 on the relative surfaces are engaged with each other in the superposed state.

[0112] Embodiment Seven

[0113] Refer to Figure 20a and 20b , a strip-shaped flexible layer support structure 9 in the figure is another implementation scheme of the concave-convex structure in Embodiment Five. In this embodiment, the concave-convex structure arranged between the layers is shear keys 33 and corresponding key grooves 34 and key holes 35 for fitting.

[0114] Specifically, in this embodiment, protruding shear keys 33 are respectively arranged at the positions of the third joint part 23, the fourth joint part 24, the fifth joint part 25 and the sixth joint part 26. The shear key 33 of the third joint part 23 protrudes towards the opposite surface of the first joint part 21, and a key groove 34 that is fitted with the shear key 33 in the superposed state is arranged on the surface of the first joint part 21 opposite to the third joint part 23; the shear key 33 of the fourth joint part 24 protrudes towards the opposite surface of the second joint part 22, and a key groove 34 that is fitted with the shear key 33 in the superposed state is arranged on the surface of the second joint part 22 opposite to the fourth joint part 24; the fifth joint part 25 and the sixth joint part 26 are both provided with shear keys 33 protruding towards the first thin plate 1 and the second thin plate 2 respectively, and key holes 35 that are fitted with the shear keys 33 on the fifth joint part 25 and the sixth joint part 26 respectively in the superposed state are arranged on the first thin plate 1 and the second thin plate 2. The positions of the shear keys 33, the key grooves 34 and the key holes 35 on the corresponding layers are equally spaced along the longitudinal y-axis direction of the flexible layer support structure.

[0115] The keyway 34 is a blind hole structure, and the keyhole 35 is a through hole structure. These two structures can be selected and designed according to the thickness of the layer where they are set.

[0116] In the embodiment, the cross-sectional shape of the convex tooth structure or the shear key structure can be trapezoidal, round-ended, rectangular, chamfered rectangular, triangular, special-shaped, etc. The corresponding tooth grooves, keyways or keyholes are selected according to the corresponding cross-sectional requirements. The directions of the convex teeth and the tooth grooves are parallel to each other, and can be linear in the same direction, or can be curved or zigzag.

[0117] In practical applications, the concave-convex structure provided between layers in the flexible layer support structure can also adopt a concave-convex embossed structure distributed on the layer surface. By superimposing the concave-convex embossed structures distributed in different directions, the bite force and friction force between layers are increased, thereby offsetting the interlayer shear force generated by curling the flexible layer support structure.

[0118] Embodiment Eight

[0119] This embodiment provides an extended implementation scheme for assembling a strip-shaped flexible layer support structure 9 into a panel flexible layer. This embodiment uses the strip-shaped flexible layer support structure 9 in Embodiment One as the basic unit. Horizontally in the structure, several such basic units are connected in parallel to form a wider panel flexible layer support structure 10.

[0120] See Figure 21 , on the basis of the structure of Embodiment One, at least two groups of thin plates are assembled along the transverse x-axis direction. At the positions of the first joint 21 and the second joint 23 on the side of the strip-shaped flexible layer support structure 9, the curved spring pieces at these positions are widened outwards to form the first overlapping step 51 and the third overlapping step 53. At the positions of the second joint 22 and the fourth joint 24 on the other side, the thin plates at these positions are widened outwards to form the first overlapping step 52 and the third overlapping step 54. When two or more strip-shaped flexible layer support structures 9 are spliced horizontally, these overlapping steps are mutually engaged, increasing the overlapping area at the joint and enhancing the firmness of the horizontal connection of the structure. Through Figure 21 Taking the strip-shaped flexible layer support structure 9 in Figure 22 as the unit, the overlapping platforms corresponding to each other of multiple strip-shaped flexible layer support structures 9 are overlapped and connected by means of bonding or welding with an adhesive to form the overall structure as shown in the panel flexible layer support structure 10 in

[0121] It should be noted that when an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0122] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0123] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0124] The above are only several specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantive modification made to the present invention using this concept shall fall within the scope of infringement of the protection scope of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments in any form based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. Flexible layer support structure, characterized in that: It comprises at least two stacked thin plates and at least two folding springs sandwiched between the thin plates in parallel; The folding springs are arranged in parallel along the first direction of the thin plate, and each of the folding springs is a long wave-shaped compression spring formed by connecting an even number of curved elastic sheets extending along the second direction of the thin plate in series. The folding springs have an elastic tendency to open the thin plates on both sides, and when the folding springs are compressed, all the curved elastic sheets and the thin plate are superimposed to form a layered structure; The outer edges of the curved elastic sheets at the two outer ends of the folding spring are smoothly overlapped with the adjacent thin plates, and a hollow thin-walled layer structure with bending rigidity is formed between the folding spring and the thin plate; when the thin plate is subjected to a sufficiently large overlapping pressure in the deformation direction of the folding spring, all the thin plates and the folding springs of the flexible layer supporting structure are overlapped into a bendable or curled overlapping flexible layer structure, and after the overlapping pressure is removed, the folding spring quickly and elastically stretches the thin plate to restore it to its original state.

2. The flexible layer support structure according to claim 1, wherein the thin plate comprises a first thin plate and a second thin plate; all folding springs are distributed in the projection area where the first thin plate and the second thin plate overlap; The connection positions between the curved elastic sheets and the first thin plate and the second thin plate are fixed connection parts respectively, and the connection positions between the curved elastic sheets within the projection area of ​​the first thin plate and the second thin plate are free connection parts. The free connection parts translate along the first direction of the thin plates during the folding and stretching process of the folding springs. The free connection parts of adjacent folding springs are arranged facing each other or in opposite directions, and gaps are provided between the free connection parts arranged facing each other for the free connection parts to translate.

3. According to the flexible layer support structure of claim 2, the sum of the width of all curved elastic sheets on the same layer after flattening and the width of the gap between the joints is not greater than the width of the thin plate connected thereto, and the width of the gap is not less than the sum of the maximum translation strokes of the free joints on both sides thereof.

4. According to the flexible layer support structure of claim 1 or 2, the cross-section of the curved spring sheet in the first direction is a smooth curve, and the two side ends smoothly transition to a tangential connection at the fixed joint or the free joint to form a folded spring with at least one V-shaped opening.

5. According to the flexible layer support structure of claim 2, the two side edges of the first thin plate and the second thin plate along the second direction are respectively fixedly combined with side sealing folding springs, and the side sealing folding springs on the same side of the first thin plate and the second thin plate extend outward and are fixedly combined to seal the two side seams between the first thin plate and the second thin plate.

6. The flexible layer support structure according to claim 1, wherein the thin plate, folding spring and side sealing folding spring are made of one or more of metal materials, polymer materials, fiber reinforced polymers, metal wire skeletons, and porous thin plates. 7 . The flexible layer support structure according to claim 2 , wherein the fixed connection part and the free connection part are fixedly connected in a manner comprising bonding, welding, melting, pressing or riveting.

8. The flexible layer support structure according to claim 4, wherein the curvature of the cross section of the curved elastic sheet and any point after the thin plate is bent or curled satisfies the following relationship: Wherein: t is the thickness of the curved elastic sheet or thin plate; E is the elastic modulus of the curved elastic sheet or thin plate; ρ is the radius of curvature of the neutral layer of a single curved elastic sheet or thin plate; σ e is the elastic limit value of the curved elastic sheet or thin plate.

9. The flexible layer support structure according to claim 2, wherein more than two sets of folding spring groups connected in series are clamped between the first thin plate and the second thin plate, and an intermediate layer is added between the folding springs.

10. The flexible layer support structure according to claim 1, wherein at least two sets of the thin plates are assembled along the first direction, and the assembled sides of the thin plates are provided with step structures that fit together.

11. The flexible layer support structure according to claim 1, wherein the thickness of the thin plate and the curved elastic sheet is 0.001-2 mm, preferably 0.01-0.5 mm.

12. The flexible layer support structure according to claim 2, wherein the curved elastic sheet of the folding spring, the first thin plate and the second thin plate are provided with concave and convex structures that engage with each other in the superposed state of the flexible layer support structure.

13. The flexible layer support structure according to claim 12, wherein the concave and convex structures include concave and convex stripe structures arranged along the first direction or the second direction, or surface-distributed concave and convex embossing structures, or a plurality of shear keys and key grooves / holes.

14. Retractable device, characterized in that: Comprising a reel, a pressure roller and a flexible layer wound on the reel, the flexible layer adopts the flexible layer support structure according to any one of claims 1-13; A gap with a width smaller than the expanded thickness of the flexible layer is provided between the pressure roller and the reel or between the pressure rollers, and the flexible layer passes through the gap and is wound on the reel. During the winding process of the flexible layer, after being squeezed by the pressure roller and the reel, the folding springs and thin plates of the flexible layer support structure are superposed into a layered structure and then wound on the reel; During the unwinding process of the flexible layer of the flexible layer support structure, for the part of the structure that leaves the pressure roller and the reel, the folding springs expand the thin plates and restore to a rigid, flat, hollow thin-wall layer structure.

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