A multi-helical rigid foldable tubular structure

Abstract

The present invention provides a multi-spiral rigid foldable tubular structure comprising a plurality of truncated cone units connected in the axial direction, wherein the adjacent edges of the truncated cone units in the axial direction are of unequal length, so that the tubular structure formed by connecting the plurality of truncated cone units in the axial direction is spiral-shaped, and the truncated cone units have adjacent edges of equal length in the circumferential direction, so that the tubular structure of the truncated cone units is foldable in the circumferential direction. The present invention enables the head end of the tubular structure to be closed as needed without affecting its foldable properties, and the tubular structure can be connected in the circumferential direction via side edges to form a foldable tubular structure with multiple channels. The present invention can be applied to fields such as aerospace, robotics, and architectural structures, thereby resolving the problem that, in foldable tubular structures with curved axes, the curved sections of the foldable tubular structure have complex shapes and limited application areas.

Description

Technical Field

[0001] The present invention relates to the technical field of folding structures, and in particular to a multi-spiral rigid foldable tubular structure. Background Art

[0002] Foldable tubular structures have a folding function. They can be folded flat for storage and transportation, or unfolded to a working state to form a tubular channel space. They have broad application prospects in aerospace, robotics, and architectural structures. Foldable tubular structures proposed in the prior art can achieve foldability, but most of them are cylindrical structures, that is, the central axis of the entire structure is a straight line, and the ends of the foldable tubular structure are basically not closed. Foldable tubular structures with curved axes have also been proposed, but the curved sections of these structures have a relatively complex serrated shape, which limits their application.

[0003] Therefore, there is a need for a foldable tubular structure whose ends can be closed as needed without affecting its foldability. In addition, there is a need to reduce the complexity of the shape of the foldable tubular structure in the curved section in order to expand its application areas.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention and does not constitute any limitation to the present invention. Summary of the Invention

[0005] In view of the shortcomings of the prior art mentioned above, the present invention provides a multi-spiral rigid foldable tubular structure, which allows the head end of the tubular structure to be closed as needed without affecting its foldable properties, and the tubular structure can be connected through the side in the circumferential direction to form a foldable tubular structure with multiple channels. It can be applied to aerospace, robotics, building structures and other fields to solve the problem that in the foldable tubular structure with a curved axis, the shape of the curved section of the foldable tubular structure is complex and the application field is limited.

[0006] The present invention provides a multiple spiral rigid foldable tubular structure, comprising a plurality of truncated cone units connected in the axial and circumferential directions, wherein the adjacent side edges of the truncated cone units in the axial direction have different lengths, so that the tubular structure formed by connecting the plurality of truncated cone units in the axial direction is spiral-shaped, and the truncated cone units have adjacent side edges of equal length in the circumferential direction, so that the tubular structure of the truncated cone units is continuous in the circumferential direction and has foldability.

[0007] In one embodiment of the present invention, the truncated cone unit includes four planar quadrilateral side surfaces, and the planar quadrilateral side surfaces are connected by rotation between axial edges to form the sidewalls of the foldable tubular structure.

[0008] In one embodiment of the present invention, adjacent truncated cone units in the axial direction are connected by rotating the planar quadrilateral side surfaces between the axial edges to form a spiral tubular structure.

[0009] In one embodiment of the present invention, the edge length of the planar quadrilateral side surface in the truncated cone unit at the large end in the circumferential direction is greater than the edge length of the small end, and between axially adjacent truncated cone units, the edge length of the quadrilateral side surface in the large end in the circumferential direction of one truncated cone unit is equal to the edge length of the quadrilateral side surface in the small end in the circumferential direction of another truncated cone unit.

[0010] In one embodiment of the present invention, the axial edges of the plane quadrilateral side surfaces of the truncated cone unit intersect at one point at the small mouth end, so that the truncated cone unit forms a spherical four-rotation pair mechanism, ensuring the closedness and single degree of freedom of the structure.

[0011] In one embodiment of the present invention, the small opening of the plane quadrilateral side surface of the truncated cone unit at the axial end is closed or open.

[0012] In one embodiment of the present invention, the closed-end planar quadrilateral side of the truncated cone unit includes a four-corner equal vertex structure, a diagonally complementary vertex structure, and a Miura-ori vertex structure, thereby increasing the diversity and adaptability of the tubular structure.

[0013] In one embodiment of the present invention, it further comprises a plurality of circumferentially connected truncated cone units, wherein the edges connected between the truncated cone units are located in the same plane, and the plurality of circumferentially connected truncated cone units form a tubular structure with a plurality of channels.

[0014] In one embodiment of the present invention, the tubular structure formed by the truncated cone units is symmetrical about the same plane formed by the connected edges, which enhances the symmetry and aesthetics of the tubular structure and improves the stability of the overall structure.

[0015] In one embodiment of the present invention, the planar quadrilateral side surfaces in the frustum unit are general quadrilaterals.

[0016] The beneficial effects of the present invention are as follows: the tip of the tubular structure can be designed to be closed or not according to needs; when folded, the volume is small for easy storage and transportation; when unfolded, it has single and multiple pipe spaces, so that the plane quadrilateral side of the truncated cone unit in the entire tubular structure has a single rigid degree of freedom, with the advantages of simple motion control and high reliability, etc., which is of great significance and broad application prospects in many fields such as aerospace, robotics, and construction engineering.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and it is clear that a person skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0019] Figure 1 Schematic diagrams of two types of structures of the multi-helical rigid foldable tubular structure of the present invention in an unfolded state, wherein the tip of the left figure is sealed, while the tip of the right figure is not sealed;

[0020] Figure 2 is an axial schematic diagram of the multi-helical rigid foldable tubular structure of the present invention;

[0021] Figure 3 yes Figure 1 The schematic diagram of the structure of the multiple spiral rigid foldable tubular structure shown is in a fully folded state;

[0022] Figure 4 It is composed Figure 1 Schematic diagram of the local structure of 2×2 truncated cones of the multiple spiral rigid foldable tubular structure shown;

[0023] Figure 5 It is composed Figure 1 The schematic diagram of the first type of structure with four equal vertices is shown;

[0024] Figure 6 It is composed Figure 1 Schematic diagram of the second diagonally complementary vertex structure shown;

[0025] Figure 7 It is composed Figure 1 Schematic diagram of the third Miura-ori vertex structure shown;

[0026] Figure 8 yes Figure 1 A schematic plan view of the truncated cone unit during the construction process shown extending in the axial and circumferential directions;

[0027] Figure 9 FIG. 1 is a schematic diagram of a single tubular structure in one embodiment of the present invention. DETAILED DESCRIPTION

[0028] The following describes the embodiments of the present invention by means of specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and examples can be combined with each other unless they conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, not to limit the scope of protection of the present invention.

[0029] See also Figures 1 to 9 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose that can be achieved by the present invention. At the same time, the terms such as position and quantitative relationship quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0030] See also Figures 1 to 4 The present invention provides a multi-spiral rigid foldable tubular structure, comprising a plurality of truncated cone units 100 connected in the axial and circumferential directions, wherein the adjacent edges of the truncated cone units 100 in the axial direction are of different lengths, so that the tubular structure formed by connecting the plurality of truncated cone units 100 in the axial direction is spiral-shaped, and the truncated cone units 100 have adjacent edges of equal length in the circumferential direction, so that the tubular structure of the truncated cone units 100 remains continuous in the circumferential direction and has foldability. The truncated cone units 100 include four planar quadrilateral sides 101, which are connected by rotation between the edges in the axial direction to form the side walls of the foldable tubular structure. Between the truncated cone units 100 adjacent in the axial direction, a spiral tubular structure is formed by the planar quadrilateral sides 101 being connected by rotation between the edges in the circumferential direction.

[0031] Furthermore, the multi-helical rigid foldable tubular structure includes a plurality of circumferentially connected frustum units 100. The connecting edges of the frustum units 100 lie in the same plane, and the circumferentially connected frustum units 100 form a tubular structure with multiple channels. The tubular structure formed by the frustum units 100 is symmetrical about the same plane formed by the connecting edges. The planar quadrilateral side faces 101 of the frustum units 100 are generally quadrilaterals.

[0032] Specifically, in an embodiment of the present invention, the multiple spiral rigid folding tubular structure is composed of a series of planar quadrilateral sides 101, and the edges of these planar quadrilateral sides 101 are interconnected by specific intersection lines to form a rotation center axis similar to a revolute pair. This connection method ensures that adjacent planar quadrilateral sides 101 have only one degree of freedom of movement when folding and unfolding. Furthermore, this structural design enables the overall tubular structure to be unfolded and folded in both the axial direction and its approximately orthogonal direction, i.e., the circumferential direction, and when fully unfolded, the basic combination in the tubular structure, i.e., the truncated cone unit 100, will reach its maximum unfolded state. On the contrary, when fully folded, the planar quadrilateral sides 101 in each truncated cone unit 100 will form surface contact with the adjacent planar quadrilateral sides 101, thereby achieving a compact folded form.

[0033] More specifically, the top and bottom surfaces of the truncated cone unit 100 are flat surfaces of different sizes, and the side surfaces are four planar quadrilaterals. The edges of the planar quadrilateral side surfaces 101 in a truncated cone unit 100 are connected to the planar quadrilateral side surfaces 101 in adjacent truncated cone units 100 through rotation. For example, bolts, hinges, or other flexible mechanical connections can be used between each truncated cone unit 100 or each planar quadrilateral side surface 101. This design ensures rotational freedom between units, thereby giving the entire tubular structure a spiral geometry in the axial direction. The differences in size and edge lengths of each truncated cone unit 100 ensure the structural continuity and spiral characteristics, while also allowing the tubular structure to be foldable in the axial direction through the rotational connection. Similarly, the four side surfaces of each truncated cone unit 100 can be folded around the connecting edges, giving the tubular structure a high degree of flexibility. The design of the planar quadrilateral side surfaces 101 not only provides sufficient stability but also allows the structure to be folded into a compact form when needed, saving space. There may also be multiple spiral units of different sizes, so that the entire tubular structure can have a multi-level spiral form when folded or unfolded, providing higher adjustability and applicability.

[0034] Furthermore, the dual connection of the truncated cone units 100, both axially and circumferentially, creates a more complex, multi-channel tubular structure. The edges of each truncated cone unit 100 lie in the same plane, ensuring the stability of the joint and preventing unnecessary twisting or deformation. In particular, the symmetry about the plane formed by the connected edges enhances the stability of the tubular structure. This symmetrical design ensures that when the structure is subjected to stress, the load is evenly distributed, thereby avoiding localized stress concentration, increasing its resistance to compression and bending, and facilitating folding and storage.

[0035] Thus, through the structural design of the truncated cone unit 100 and its mid-plane quadrilateral side 101 and the revolute pair formed therein, a spiral rigid foldable tubular structure can be realized. This structure not only has strong spiral stability but can also be folded when needed to save space. By combining the circumferentially connected truncated cone units 100, a multi-channel, highly stable, and foldable tubular structure can be realized. This structure also has corresponding symmetry and strength when unfolded, making it suitable for a wider range of engineering and application fields. For example, it can be used in foldable structural components such as deployable spacecraft shells, heat exchanger pipes, fuel pipes, etc. In applications such as robotic arms and retractable structures, this tubular structure can be used as a flexible connecting component with good adaptability. It also provides a solution for temporary facilities that require compact storage and rapid deployment.

[0036] See also Figures 1 to 4 In one embodiment, the edge length of the planar quadrilateral side surface 101 in the truncated cone unit 100 at the large end in the circumferential direction is greater than the edge length at the small end, and between axially adjacent truncated cone units 100, the edge length of the quadrilateral side surface in the large end in the circumferential direction of one truncated cone unit 100 is equal to the edge length of the quadrilateral side surface in the small end in the circumferential direction of another truncated cone unit 100.

[0037] Specifically, in the embodiment of the present invention, two types of multiple spiral rigid foldable tubular structures in an expanded state are constructed based on the truncated cone unit 100. Figure 1 As shown on the left, it is a multi-helical rigid foldable tubular structure with one end closed. Figure 1 The right side of the middle figure shows a multi-helical rigid foldable tubular structure with both ends open. Figure 1 In the left figure, the area marked by the red solid frame line is the frustum unit 100 , and each frustum unit 100 has four planar quadrilateral side surfaces 101 .

[0038] In a rigid, foldable tubular structure with one end closed, precise control of the folding and unfolding of the tubular structure enables accurate grasping and handling of objects, making it suitable for applications such as robotic grippers that require delicate manipulation. In a rigid, foldable tubular structure with both ends open, greater flexibility allows for easier adaptation to varying lengths and shapes, making it suitable for applications such as robotic arms that require variable lengths.

[0039] See also Figure 2 , which is a schematic diagram of the axial side of a multiple spiral rigid foldable tubular structure, showing the front and rear axial side views of the multiple spiral rigid foldable tubular structure. Figure 2 The left side shows a front view of a multi-helical rigid foldable tubular structure. Figure 2 The center right side shows the rear view of the multi-helical rigid foldable tubular structure. Figure 2 The multi-layered spiral form of the present invention when folded or unfolded is intuitively displayed, and the appearance and structure of the present invention can be better understood.

[0040] For more details, please see the attached Figure 4 , which is a schematic diagram of the structure of adjacent 2×2 truncated cone units 100 of a multiple spiral rigid foldable tubular structure, showing the connection method of adjacent truncated cone units 100 in two directions of a single-layer annular truncated cone unit 100. The structure of the truncated cone unit 100 is symmetrical about the A1A3F3F1 plane, and the three axial edges A1A2A3, C1C2C3, and F1F2F3 are all located in this plane. Figure 4 By mirroring the structure shown in the figure about the plane A1A3F3F1, a multiple rigid folded tubular structure formed by 2×2 truncated cone units 100 can be obtained. In the axial direction, the connection line between two adjacent truncated cone units 100 is the intersection line of the quadrilateral, such as A2B2, B2C2 and two sides symmetrical about the plane A1A3F3F1 (not shown in the figure). In the circumferential direction, which is approximately orthogonal to the axis, two adjacent truncated cone units 100 are connected by the intersection line whose side edges are located in the same plane, such as sides A1A2, C1C2, F1F2, etc.

[0041] See also Figures 5 and 6 In one embodiment, the closed-end planar quadrilateral side surface 101 of the truncated cone unit 100 includes a four-corner equal vertex structure, a diagonally complementary vertex structure, and a Miura-ori vertex structure.

[0042] Specifically, in the embodiment of the present invention, Figure 5 、 Figure 6 and Figure 7 As shown in Figure 1, there are three types of four-fold vertex structures that make up the multiple rigid folded tubular structure, which are distributed throughout the structure. Figure 4 For example, B1, B2, B3 and E1, E2, E3 and other vertices in the axis direction are Figure 6 The diagonal complementary vertex structure shown. In the circumferential direction, A1, A2, A3, C1, C2, C3, F1, F2, F3 and other vertices in the axial direction are Figure 7 The Miura-ori vertex structure shown. In the single spiral rigid foldable tubular structure, A1, A2, A3, C1, C2, C3, F1, F2, F3 and other vertices in the axial direction are Figure 5 The four-corner equal vertex structure shown in the figure. And precisely because of the special features of these vertices, the tubular structure can be folded, realizing the transition from single to multiple structures. Figure 5 、 Figure 6 and Figure 7The vertices shown can be designed as part of a spherical 4R mechanism. Specifically, the three vertex structures S10, S20, and S30 form a rotation center axis through the first connecting line, which is similar to the first rotation pair in the mechanism. Similarly, the vertices S11, S21, and S31 form a second rotation center axis through the second connecting line, the vertices S12, S22, and S32 form a third rotation center axis through the third connecting line, and the vertices S13, S23, and S33 form a fourth rotation center axis through the fourth connecting line, and their α, β, π-α, and (π-β) are the plane angles of the corresponding vertex structures. In this way, in the tubular structure of this design, the panels of each planar quadrilateral side 101 act as connecting rods, and together constitute a spherical four-rotation pair mechanism.

[0043] See also Figures 8 and 9 In one embodiment, the axial edges of the planar quadrilateral side surface 101 of the frustum unit 100 intersect at a point at the small end, forming a spherical four-rotation joint mechanism. The small end of the planar quadrilateral side surface 101 of the frustum unit 100 at the axial end is closed or open.

[0044] Specifically, in the truncated cone unit 100 of the embodiment of the present invention, the axial edges of the plane quadrilateral side 101 thereof intersect at one point at the extension line of the small mouth end, that is, there are exactly four such intersection lines converging at each vertex thereof, forming a spherical four-rotation pair (4R) mechanism, so that the mechanism of the cross-sectional unit has only one rigid degree of freedom. Through the geometric relationship that the extension lines of the edges of the plane quadrilateral side 101 in the truncated cone unit 100 intersect at one point, a mechanism structure that can rotate freely in three-dimensional space is formed. It provides the possibility of realizing complex spatial rotation and is widely used in fields that require multi-degree-of-freedom rotation, such as robotics, aerospace, and precision machinery.

[0045] More specifically, if Figure 8 FIG. 1 is a plan view schematically illustrating the design process of a multiple spiral rigid foldable tubular structure, including how the truncated cone unit 100 extends along the axial direction and the circumferential direction, and how these extensions affect the shape and size of the overall structure. Figure 8 It is composed of four triangles at the front and four quadrilaterals connected to it. Triangles can be divided into two categories. The three internal angles of the first type of triangle are α O , α A and α B , the three interior angles of the second type triangle are α O ,π-β B and π-α A , where α O is the plane angle at the tip, and the plane angles satisfy the relationship α B =π-αO -α A and β B =π-α A +α O In the axial direction, the four triangles at the front end and the four plane quadrilateral basic units connected to them can be divided into two categories, among which the four internal angles of the first type of quadrilateral are α A , α A , β B and α B , the four interior angles of the second type plane quadrilateral are π-α B ,π-β B ,π-α A and π-α A . Figure 8 The left side shows the process of extending a single rigid folded tubular structure along the axis. Each ring unit is a truncated cone based on the Bricard octahedron. The previous ring unit intersects with the next ring unit, and the cone part of the next ring unit is removed (i.e. Figure 7 By analogy, a single spiral-shaped foldable curved tube structure with a curved axis can be obtained, and the front end can be closed. Figure 8 The right side shows the extension process of a single rigid folded tubular structure in the circumferential direction. Figure 6 Based on the Miura-ori vertex type shown in FIG, a single spiral rigid foldable tubular structure is combined to obtain a multiple curved tubular structure with a curved axis, that is, a multiple spiral rigid foldable tubular structure. Figure 4 As shown, the upper tubular structure of the 2×2 building unit is designed to have the vertices at C1, C2, and C3 as Figure 7 The Miura-ori vertex shown, i.e., the extension in the circumferential direction, realizes the combination of the adjacent double tubular structures and the bent tubular structure, resulting in a 2×2 building unit upper tubular structure.

[0046] See also Figure 9 , which is Figure 8 The left figure shows that the front and rear frustum units 100 intersect, and the cone part of the rear section is removed (i.e. Figure 7 The O′ABCD cone in the figure, where D and B coincide, is extended in the axial direction to form a single spiral rigid folded tubular structure. Its vertex types include Figure 5 and Figure 6 The vertex shown is a single elbow structure with a bending axis, and its side surface is a general quadrilateral.

[0047] In summary, the present invention provides a multi-helical, rigid, and foldable tubular structure. The tip of the tubular structure can be designed to be closed or closed as needed. When folded, it is compact, making it convenient for storage and transportation. When unfolded, it provides both single and multiple tube spaces. The planar quadrilateral sides of the truncated cone units within the tubular structure have a single rigid degree of freedom, offering advantages such as simple motion control and high reliability.

[0048] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A multi-helical rigid foldable tubular structure, characterized in that: The invention relates to a plurality of truncated cone units (100) connected in the axial and circumferential directions, wherein the adjacent side edges of the truncated cone units (100) in the axial direction are of different lengths, so that a tubular structure formed by connecting the plurality of truncated cone units (100) in the axial direction is spiral-shaped, and the truncated cone units (100) have adjacent side edges of equal length in the circumferential direction, so that the tubular structure of the truncated cone units (100) is continuous in the circumferential direction and has foldability; The truncated cone unit (100) comprises four planar quadrilateral side surfaces (101), wherein the planar quadrilateral side surfaces (101) are connected by rotation between axial edges to form side walls of a foldable tubular structure; The tubular structure further comprises a plurality of circumferentially connected truncated cone units (100), wherein the edges connected between the truncated cone units (100) are located in the same plane, and the plurality of circumferentially connected truncated cone units (100) form a tubular structure with a plurality of channels.

2. The tubular structure according to claim 1, characterized in that The axially adjacent truncated cone units (100) are connected by rotating the planar quadrilateral side surfaces (101) between the edges in the circumferential direction to form a spiral tubular structure.

3. The tubular structure according to claim 2, characterized in that The edge length of the planar quadrilateral side surface (101) in the truncated cone unit (100) at the large end in the circumferential direction is greater than the edge length at the small end, and between the axially adjacent truncated cone units (100), the edge length of the quadrilateral side surface in the large end in the circumferential direction of one truncated cone unit (100) is equal to the edge length of the quadrilateral side surface in the small end in the circumferential direction of another truncated cone unit (100).

4. The tubular structure according to claim 3, characterized in that The extended lines of the axial edges of the plane quadrilateral side surface (101) in the truncated cone unit (100) intersect at one point at the small mouth end, so that the truncated cone unit (100) forms a spherical four-rotation pair mechanism.

5. The tubular structure according to claim 4, characterized in that The small mouth end of the plane quadrilateral side (101) in the truncated cone unit (100) at the axial end is closed or open.

6. The tubular structure according to claim 5, characterized in that The plane quadrilateral side surface (101) with a closed small end in the truncated cone unit (100) includes a four-corner equal vertex structure, a diagonally complementary vertex structure, and a Miura-ori vertex structure.

7. The tubular structure according to claim 6, characterized in that The tubular structure formed by the truncated cone units (100) is symmetrical about the same plane formed by the connected edges.

8. The tubular structure according to any one of claims 1 to 7, characterized in that The plane quadrilateral side surface (101) in the truncated cone unit (100) is a general quadrilateral.

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