Multi-spiral rigid foldable tubular structure

Abstract

The invention provides a multi-spiral rigid foldable tubular structure which comprises a plurality of truncated cone units which are connected in the axial direction, and the lengths of adjacent side edges of the truncated cone units in the axial direction are unequal, so that the tubular structure formed by connecting the truncated cone units in the axial direction is spiral. The truncated cone units are provided with adjacent side edges with the same length in the circumferential direction so that the tubular structures of the truncated cone units can be folded in the circumferential direction. The head end of the tubular structure can be closed according to needs, the foldable characteristic of the tubular structure is not affected, the tubular structure can be connected through the side edges in the circumferential direction, the foldable tubular structure with the multiple channels is formed, the foldable tubular structure can be applied to the fields of aerospace, robots, building structures and the like, and the problem that in the foldable tubular structure with the bent axis, the foldable tubular structure cannot be folded easily is solved. The problems that the bent section folding tubular structure is complex in shape and limited in application field exist.

Description

Technical Field

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

[0002] The foldable tubular structure has a folding function. It can be folded flat for storage and transportation, or unfolded to a working state to form a tubular channel space. It has broad application prospects in the fields of aerospace, robotics, and building structures. The foldable tubular structure proposed in the prior art can achieve the foldable property, 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. There are also foldable tubular structures with curved axes, but the local curved section of the structure is a complex serrated shape, so the application is limited.

[0003] Therefore, for a foldable tubular structure, there is a need for its ends to be closed as needed without affecting its foldability. In addition, in a foldable tubular structure with a curved axis, there is also a need to reduce the complexity of the shape of the foldable tubular structure in the curved section to expand the applicable field.

[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, by allowing 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. The structure 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 direction and the circumferential direction, 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, 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 sides, and the planar quadrilateral sides are connected by rotation between the edges in the axial direction to form the side wall 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 sides between the edges in the axial direction 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 one truncated cone unit at the large end in the circumferential direction is equal to the edge length of the quadrilateral side surface in another truncated cone unit at the small end in the circumferential direction.

[0010] In one embodiment of the present invention, the extended lines of 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 flat 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, which increases the diversity and adaptability of the tubular structure.

[0013] In one embodiment of the present invention, it further comprises a plurality of circumferentially connected frustum units, wherein the edges connected between the frustum units are located in the same plane, and the plurality of circumferentially connected frustum units form a tubular structure of 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 plane 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 as required; when folded, the volume is small for easy storage and transportation; when unfolded, the structure 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, and has the advantages of simple motion control and high reliability. The structure has important significance and broad application prospects in many fields such as aerospace, robotics, and construction engineering.

[0017] It is to be understood that both 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 drawings herein are incorporated into the specification and constitute a part of the specification, showing 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 for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. 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 a multiple spiral 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 of 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 of Figure 1 The schematic diagram of the first structure with four equal vertices is shown;

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

[0025] Figure 7 It is composed of 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 extending in the axial and circumferential directions during the construction process shown;

[0027] Fig. 9 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 specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied by other different specific embodiments, and the details in this specification can also be modified or changed in various ways 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 embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are to describe specific specific embodiments, rather than 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 in 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, so they have no substantial technical significance. Any structural modification, change in proportional relationship, or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as position and quantitative relationship cited 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 multiple spiral rigid foldable tubular structure, comprising 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 the tubular structure formed by connecting a 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 remains continuous in the circumferential direction and has foldability. The truncated cone units 100 include four planar quadrilateral side surfaces 101, and the planar quadrilateral side surfaces 101 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, the spiral tubular structure is formed by the planar quadrilateral side surfaces 101 being connected by rotation between the edges in the circumferential direction.

[0031] Furthermore, the multiple spiral rigid foldable tubular structure also includes a plurality of circumferentially connected truncated cone units 100, the edges connected between the truncated cone units 100 are located in the same plane, and the truncated cone units 100 connected in the circumferential direction form a tubular structure of a plurality of channels. The tubular structure formed by the truncated cone units 100 is symmetrical about the same plane formed by the connected edges. The plane quadrilateral side surface 101 in the truncated cone unit 100 is a general quadrilateral.

[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 to achieve a compact folded form.

[0033] More specifically, the top and bottom surfaces of the truncated cone unit 100 are planes of different sizes, and the side surfaces are four planar quadrilaterals. The edges of the planar quadrilateral side surfaces 101 in the truncated cone unit 100 are connected to the planar quadrilateral side surfaces 101 in the adjacent truncated cone unit 100 by rotation. For example, bolts, hinges or other flexible mechanical connection methods can be used between each truncated cone unit 100 or each planar quadrilateral side surface 101. Such a design can ensure the rotational freedom between the units, so that the entire tubular structure has a spiral geometric shape in the axial direction. The difference in size and edge length of each truncated cone unit 100 ensures the continuity and spiral characteristics of the structure, and at the same time enables the tubular structure to form a foldable function in the axial direction through rotational connection. Similarly, the four sides of each truncated cone unit 100 can be folded around the connected edges, so that the tubular structure has strong flexibility. The design of the planar quadrilateral side surface 101 not only provides sufficient stability, but also enables the structure to be folded into a compact form when needed to save space. There may also be a plurality of spiral units of different sizes, so that the entire tubular structure can have a multi-level spiral shape when folded or unfolded, thereby providing higher adjustability and applicability.

[0034] Furthermore, the double connection of the truncated cone units 100 in the axial and circumferential directions forms a more complex and multi-channel tubular structure. The edges of each truncated cone unit 100 are located in the same plane, which ensures the stability of the connection and avoids unnecessary distortion or deformation. In particular, the symmetry about the same plane formed by the connected edges can enhance the stability of the tubular structure. The symmetrical design allows the load to be evenly distributed when the structure is subjected to force, thereby avoiding local stress concentration, increasing its ability to resist compression and bending, and facilitating folding and storage.

[0035] In this way, through the structural design of the truncated cone unit 100 and the plane quadrilateral side 101 thereof and the revolute pair formed, a spiral rigid foldable tubular structure can be realized, which not only has strong spiral stability, but also can be folded when needed to save space. By combining the circumferentially connected truncated cone units 100, a tubular structure with multiple channels, high stability and foldability can be realized, and has corresponding symmetry and strength when unfolded, which is suitable for more engineering and application fields. For example, it is used for foldable structural components, such as deployable spacecraft shells, heat exchanger pipes, fuel pipes, etc. In applications such as robot arms and retractable structures, this tubular structure can be used as a flexible connection component with good adaptability, and also provides solutions in temporary facilities that need to be compactly stored and quickly unfolded.

[0036] See also Figures 1 to 4 In one embodiment, the edge length of the planar quadrilateral side surface 101 at the large end in the circumferential direction of the truncated cone unit 100 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 at the large end in the circumferential direction of one truncated cone unit 100 is equal to the edge length of the quadrilateral side surface at 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 unfolded 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 sides 101 .

[0038] In a rigid folding tubular structure with one end closed, precise control of the folding and unfolding process of the tubular structure can achieve accurate grasping and handling of objects, which is suitable for applications such as mechanical claws that require delicate operations. In a rigid folding tubular structure with both ends open, by providing better flexibility, it can be more easily adapted to the needs of different lengths and shapes, which is suitable for applications such as mechanical 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 middle 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 The structure shown in the figure is mirrored about the plane A1A3F3F1, and 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 a quadrilateral intersection line, such as A2B2, B2C2 and its two sides symmetrical about the A1A3F3F1 plane (not shown in the figure); in the direction approximately orthogonal to the axis, that is, in the circumferential direction, two adjacent truncated cone units 100 are connected by intersection lines whose sides are located in the same plane, such as A1A2, C1C2, F1F2 and other sides.

[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 it is precisely because of the special features of these vertices that the tubular structure can be folded, realizing the transition from single-layer to multiple-layer structure. 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 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 to 9 In one embodiment, the extended lines of the axial edges of the plane quadrilateral side surface 101 of 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. The small mouth end of the plane quadrilateral side surface 101 of the truncated cone 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 extension lines of the axial edges of the plane quadrilateral side 101 intersect at one point at the small end, that is, there are exactly four such intersection lines converging at each vertex, 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, Figure 8 1 is a schematic plan view of 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 plane quadrilateral basic units 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-layer 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. 1 , 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 in the figure, the upper tubular structure of the 2×2 building unit is designed by designing 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 Fig. 9 , which is Figure 8 As shown in the left figure, the front and rear frustum units 100 intersect, and the cone portion of the rear section is removed (i.e. Figure 7 The O′ABCD cone in the figure, where D and B coincide with each other), is a single spiral rigid folded tubular structure extending in the axial direction. Its vertex types include Figure 5 and Figure 6 The vertex shown is a single-bend tube structure with a bending axis, and its side surface is a general quadrilateral.

[0047] In summary, the present invention provides a multiple spiral rigid foldable tubular structure, the tip of which can be designed to be closed or not according to needs, and is small in size when folded for easy storage and transportation, and has single and multiple pipe spaces when unfolded. The plane quadrilateral side of the truncated cone unit in the entire tubular structure has a single rigid degree of freedom, which has the advantages of 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 familiar with 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 a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A multi-helical rigid foldable tubular structure, characterized in that: The invention comprises a plurality of truncated cone units (100) connected in the axial direction and the circumferential direction, 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.

2. The tubular structure according to claim 1, characterized in that The truncated cone unit (100) comprises four planar quadrilateral side surfaces (101), and the planar quadrilateral side surfaces (101) are connected by rotation between the edges in the axial direction to form the side walls of the foldable tubular structure.

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

4. The tubular structure according to claim 3, 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).

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

6. The tubular structure according to claim 5, 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.

7. The tubular structure according to claim 6, characterized in that The planar 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.

8. The tubular structure according to claim 2, characterized in that It also 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.

9. The tubular structure according to claim 8, characterized in that The tubular structure formed by the truncated cone units (100) is symmetrical about the same plane formed by the connected edges.

10. The tubular structure according to any one of claims 1 to 9, characterized in that: The plane quadrilateral side surface (101) in the frustum unit (100) is a general quadrilateral.

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