Abstract:
A deployable structure comprising a plurality of pairs of hingeably connected members, a first hinge element; and a second hinge element; wherein the two members of each pair of hingeably connected members are connected to the first and the second hinge elements respectively; and wherein the first hinge element is capable of being stabilized for facilitating stabilization of the deployable structure into a deployed state.

Description:
FIELD OF INVENTION 
       [0001]    The present invention relates broadly to deployable structures and an assembly comprising a plurality of deployable structures. 
       BACKGROUND 
       [0002]    Deployable structures, for example, space frames, beam structures, etc., are required in a wide variety of applications. These structures are usually transported in a folded state to a chosen site for deployment. After use, they may be folded back and stored for redeployment. 
         [0003]    In general, conventional deployable structures suffer from poor structural configurations in a fully deployed state. Many conventional foldable structures deploy into non-optimal shapes as the requirement for the structure to be foldable imposes geometric constraints that are sometimes contrary to structural requirements. Further, the deployable structures may be bulky in a folded state, and are mechanically complex in design. 
         [0004]    Typical self-stabilizing or “clicking” or “self-locking” deployable structures do not provide structurally optimal forms in the fully deployed state. Some of them require enormous forces and coordination for deployment and undergo significant bending during deployment. Other forms of structural systems require a large number of individual components and complicated assembly operations to form the structure, making deployment or folding the structures time consuming and costly. 
       SUMMARY 
       [0005]    In accordance with a first aspect of the present invention there is provided a deployable structure comprising: 
         [0006]    a plurality of pairs of hingeably connected members, 
         [0007]    a first hinge element; and 
         [0008]    a second hinge element; 
         [0000]    wherein the two members of each pair of hingeably connected members are connected to the first and the second hinge elements respectively; and 
         [0009]    wherein the first hinge element is capable of being stabilized for facilitating stabilization of the deployable structure into a deployed state. 
         [0010]    The deployable structure may further comprise: 
         [0011]    a central member wherein the first and second hinge elements are connected to different ends of the central member; and 
         [0012]    wherein one portion of the first hinge element is detachably connected to the central member such that the first hinge element is stabilized when connected to the central member. 
         [0013]    The deployable structure may further comprise a fastening element to fasten the first hinge element to the central member. 
         [0014]    The deployable structure may comprise three or more pairs of hingeably connected members. 
         [0015]    One of the two members in each pair of hingeably connected members may be connected to the other member of said pair by at least one third hinge element. 
         [0016]    The deployable structure may further comprise cables or flexible elements connecting the third hinge elements. 
         [0017]    One of the two members in each pair of hingeably connected members may connected to the other member of said pair via one or more secondary members. 
         [0018]    The secondary members may be substantially parallel to an imaginary line joining the first and second hinge elements, when the deployable structure is in the deployed state. 
         [0019]    The hinge elements may allow a single degree-of-freedom of movement. 
         [0020]    The members may comprise one or more of a group comprising struts, rods, tubes, telescopic elements, self stabilizing elements and cables. 
         [0021]    The deployable structure may further comprise one or more energy stored devices for facilitating deployment and/or folding of the deployable structure. 
         [0022]    In accordance with a second aspect of the present invention there is provided an assembly comprising a plurality of deployable structures, each deployable structure comprising: 
         [0023]    a plurality of pairs of hingeably connected members, 
         [0024]    a first hinge element; and 
         [0025]    a second hinge element; 
         [0000]    wherein the two members of each pair of hingeably connected members are connected to the first and the second hinge element respectively; and 
         [0026]    wherein the first hinge element is capable of being stabilized for facilitating stabilizing the deployable structure in a deployed state. 
         [0027]    Each deployable structure may further comprise: 
         [0028]    a central member wherein the first and second hinge elements are connected to different ends of the central member; and 
         [0029]    wherein one portion of the first hinge element is detachably connected to the central member such that the first hinge element is stabilized when connected to the central member. 
         [0030]    The assembly may further comprise at least one cable or connecting the plurality of deployable structures. 
         [0031]    The at least one cable or may connect hinge elements of the plurality of deployable structures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]    Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which: 
           [0033]      FIG. 1  is a schematic representation of a deployable structure according to an embodiment of the present invention; 
           [0034]      FIG. 2  is a schematic representation of the deployable structure of  FIG. 1  when partially folded; 
           [0035]      FIG. 3   a  is a schematic representation of a plurality of connected deployable structures according to another embodiment of the present invention; 
           [0036]      FIG. 3   b  is a schematic representation of a plurality of connected deployable structures according to another embodiment of the present invention; 
           [0037]      FIG. 4   a  is a schematic representation of a plurality of connected deployable structures according to another embodiment of the present invention; 
           [0038]      FIG. 4   b  is a schematic representation of a plurality of connected deployable structures according to another embodiment of the present invention; 
           [0039]      FIG. 4   c  is a schematic representation of a plurality of connected deployable structures according to another embodiment of the present invention; 
           [0040]      FIG. 5  is a schematic representation of the deployable structure  FIG. 1 , showing an upper plane, a middle plane and a lower plane; 
           [0041]      FIG. 6  is a schematic representation of a structural unit according to another embodiment of the present invention; 
           [0042]      FIG. 7  is a schematic representation of a structural unit according to yet another embodiment of the present invention; 
           [0043]      FIG. 8  is a schematic representation of a structural unit according to another embodiment of the present invention; 
           [0044]      FIG. 9  is a schematic representation of a structural unit according to yet another embodiment of the present invention; 
           [0045]      FIG. 10  is a schematic representation of a structural unit according to another embodiment of the present invention 
       
    
    
     DETAILED DESCRIPTION  
       [0046]    Generally, the described embodiments relate to a structural system of foldable, deployable or collapsible structures made up of interconnected units that are extensible and collapsible into various structural shapes, for example, space frames, panels, columns, domes, vaults. 
         [0047]    A schematic representation of a deployable structure  100  in an example embodiment is shown in  FIG. 1 . In this embodiment, the deployable structure  100  comprises a central element  130 , four upper elements  140 , four lower elements  150 , and a network of cables or flexible elements  170 . In this embodiment, the upper and lower elements  140 ,  150  are struts. However, it should be appreciated that the upper and lower elements may be in the form of rods, tubes, cables, etc, or a combination of different elements. The four lower elements  150  are attached to a lower hinge  104 , and the four upper elements  140  are attached to an upper hinge  108 . Each of the upper elements  140  is hingeably connected to a corresponding lower element  150  by a middle hinge  112 , forming a pair. Each middle hinge  112  is connected to adjacent middle hinges  112  by the network of cables  170 . The upper and lower elements  140 ,  150  may be made of metallic or composite materials. 
         [0048]    The hinges  104 ,  108 ,  112  allow the upper and lower elements  140 ,  150  to rotate in a single degree-of-freedom, acting as pin-joints, and enable deployment and folding of the deployable structure  100 . 
         [0049]    When the deployable structure  100  is in a deployed state, one end of a central element  130  is detachably connected to the upper elements  140  via the upper hinge  108 , and the other end of the central element  130  is connected to the lower elements  150  via the lower hinge  104 . This allows the deployable structure  100  to be folded or deployed by attaching or detaching the end of the central element  130  from the upper hinge  108 . It should be appreciated that the central element  130  may be detachably connected to either the lower hinge  104  or the upper hinge  108  at one end or both ends. Alternatively, the central element  130  may comprise two sections (not shown) detachably joined with each end of the central element  130  attached to the upper hinge  108  and the lower hinge  104 , respectively. The upper hinge  108  may have means for disengaging and engaging the detachable end of the central element  130 , for example, a fastening mechanism (not shown) may be used to lock the detachable end of the central element  130  to the upper hinge  108  when the deployable structure  100  is fully deployed. 
         [0050]    When the deployable structure  100  is in an upright, deployed state as shown in  FIG. 1 , the central element  130  is substantially perpendicular to the ground  190 . 
         [0051]    The deployable structure  100  in  FIG. 1  is in the form of a square module. However, it should be appreciated that numerous other configurations, for example, triangular, hexagonal, pentagonal or other polygonal shapes may be formed with substantially the same arrangement, which has the central element  130  connecting the lower and upper hinges  104 ,  108 . 
         [0052]    The basic unit shown in  FIG. 1  can also be implemented without the central member by restraining the geometry of the upper elements ( 140 ) and lower elements  150  by means of a lockable hinges  108 ,  112 ,  104 , which restrain the movement of the elements  140 ,  150  when the deployable structure  100  is in the fully deployed state. 
         [0053]    In another example embodiment, upper hinges  1080  may be disposed between lower hinges  1040  and a network of cables or flexible members  1700  joining the middle hinges  1120 , as shown in  FIG. 10 . 
         [0054]      FIG. 2  is a schematic representation of the deployable structure  100  in a partially folded state. The deployable structure  100  is folded from the fully deployed state by detaching the central element  130  from the upper hinge  108 . This may be done by various means, for example, by releasing the fastening mechanism (not shown) on the upper hinge  108 . Where the central element  130  is in the form of a telescopic element, the length of the central element  130  may be reduced during detachment of the central element  130  from the upper hinge  108 . When the detachable end of the central element  130  is disconnected from the upper hinge  108 , the elements  140 ,  150  are folded towards the central member. 
         [0055]    By exploiting the flexibility of the cables or flexible members  170  to improve the foldability of the deployable structure  100 , improved compaction of the structure  100  can be achieved, when the structure  100  is folded. Further, the use of the cables or flexible members  170  make the deployable structure  100  significantly lighter and stiffer, compared to conventional designs. The mechanical complexity of the structure is also minimised. The cables  170  also carry tensional loads efficiently and help to stabilise the geometry of the deployable structure  100 . Furthermore, a wide variety of structural shapes may be created by varying the length of the cables  170 . The cables  170  may be metallic or composite materials cables, fiber-based cables, etc. 
         [0056]    A plurality of deployable structures may be connected and deployed to form structural systems. For example, a plurality of the deployable structures  300  may be connected in-line to form a beam  301 , as shown in  FIG. 3   a . A cable or  390  may be used to join the lower hinge  304  of each deployable structure  300  to form the beam  301 . The middle hinges e.g.  307  may be of an integral type between adjacent individual structures  300 , i.e. one middle hinge e.g.  307  may be “shared” between adjacent individual structures  300 . 
         [0057]    In another example embodiment, a plurality of the deployable structures  350  may be connected in-line to form a beam  302 , as shown in  FIG. 3   b.  A cable  391  may be used to connect the upper hinges  306 , in addition to the cable  391  joining the lower hinges  305 . 
         [0058]    Alternatively, a plurality of deployable structures  400  may be connected and deployed in an array to form space frames and vaults, as shown in  FIG. 4   a . Similarly, connecting cables  490  may be used to join the lower hinges  404  of each of the deployable structures  400 . Further, a combination of beam and space frame structures can also be synthesized using variations of the deployable structure  400 . For example, a barrel vault configuration can be created by changing the lengths of the connecting cables  491  joining the lower elements  406 , as shown in  FIG. 4   b.    
         [0059]      FIG. 4   c  illustrates another example embodiment with additional connecting cables  493  connecting the upper elements  407 . It should be appreciated that the connecting cables  490 ,  493 , may be in other forms, for example, elements.  FIGS. 4   b  and  4   c  show only one row of connected deployable structures. However, it should be appreciated that the length of the connecting cables  490  joining the array of deployable structures  400  (shown in  FIG. 4   a ) may be changed to achieve similar configurations shown in  FIGS. 4   b  and  4   c.  Other shapes, for example, a dome, can also be created by using a combination of hexagonal, pentagonal, triangular and other structural shapes. 
         [0060]    Referring to  FIG. 5 , the deployable structure  500  may be divided into three planes—a first plane (lower plane)  510  comprising the lower hinge  504 , a second plane (upper plane)  520  comprising the upper hinge  508  and a third plane (middle plane)  530 , between the lower plane  510  and the upper plane  520 , comprising by the middle hinges  512 . In this example embodiment, a network of cables (not shown), a membrane or sheet, etc may be attached to the upper and/or middle and/or lower planes  510 ,  520 ,  530  respectively to form various types of structural systems. It should be appreciated that a plurality of planes may be provided between the lower and upper planes  510 ,  520 . 
         [0061]    Alternative embodiments of the deployable structure are shown in  FIGS. 6 to 10 . 
         [0062]    Vertical rods  620 , shown in  FIG. 6 , may be attached to the middle hinges  612  of the deployable structure  600  to facilitate attachment of sheets of fabric material or to increase the depth of the structural unit, or for bracing and other purposes. 
         [0063]    Other types of connecting attachments may be added to the hinges to enable the attachment to other structural units or sheets or fabric material.  FIG. 7  shows a schematic representation of the deployable structure  700  according to another example embodiment. The deployable structure  700  has two layers of middle hinges comprising upper middle hinges  712  and lower middle hinges  714 . A vertical member  765  connects each of the upper middle hinges  712  to a corresponding lower middle hinge  714 , defining a parallelepiped. 
         [0064]    Alternatively, other forms of deployable structural units (e.g.  895 ) may be disposed between an upper middle plane  862  and a lower middle plane  864  of the deployable structure  800 , as shown in  FIG. 8 , to increase the depth of the deployable structure  800 , improve structural efficiency and to facilitate deployment of the structure  800 . In this example, the additional structural units  895  comprise a pair of rods  896 ,  897  pivoted to each other substantially in the centre. 
         [0065]    In another example embodiment, the deployable structure  900  may comprise cables  970  connecting the middle hinges  912  diagonally, as shown in  FIG. 9 . The deployable structure  900  may also have additional cables connecting the middle hinges  912  (compare the cables  170  in  FIG. 1 ). 
         [0066]    It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention, as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive. 
         [0067]    For example, the central element may have energy stored devices such as springs, that help in the deployment process. Various telescopic and cable-realized mechanisms may be used to assist the coordinated deployment of the structure. Springs may be incorporated into the hinges for the same purpose. The cables may also be spring loaded or may have elastic attachments to prevent entanglement during deployment of the structure. 
         [0068]    The elements may be telescopic or telescopic and lockable to provide flexibility in configuring the structure. 
         [0069]    Further, the deployable structures may be combined with structural kinematic chains to facilitate deployment. 
         [0070]    The cables and/or the elements may be pre-tensioned to enhance the structural behavior of the unit. 
         [0071]    Fabric, sheet and other forms of covering material may be attached to the rods or cables by introducing additional connectors or by designing their shape to facilitate direct attachment. 
         [0072]    By using cables that fold and attachable members (e.g. struts) that do not constrain the design, the example embodiments described above allow the fully deployed state of the structure to be structurally optimal. 
         [0073]    The structures in the example embodiments achieve quick installation with the minimal assembly operations. The structure is substantially free of stress during deployment and in the folded configuration. 
         [0074]    Possible industrial applications of the deployable structures include a wide range of temporary and permanent structures such as exhibition, emergency, entertainment, military, and space structures that require rapid deployment. It also can be used for shelters, roofs, bridges, pylons, radars, vaults and structures of various configurations.