Patent Publication Number: US-2021172466-A1

Title: Lattice for structures

Description:
FIELD 
     The present invention relates to space structures, and more particularly, to lattices maximizing strength-to-mass ratio, facilitating large yet low-mass structures in space. 
     BACKGROUND 
     The current state-of-the-art for the construction of large space structures rely on manufacturing methods that result in the permanent jointing of truss-joint connections. Once the mission is complete, the large structure must be de-orbited or abandoned in a graveyard orbit. A semi-permanent structure could be reconfigured to meet the requirements for a new mission and eliminate the need to launch new material for a new large space structure. 
     SUMMARY 
     Certain embodiments of the present invention may provide solutions to the problems and needs in the art that have not yet been fully identified, appreciated, or solved by current space structure systems. For example, some embodiments pertain to lattices that maximize strength-to-mass ratio, facilitating large yet low-mass structures in space. 
     In an embodiment, a system includes a lattice joint housing and a plurality of structural joints. Each of the plurality of structural joints have a side entry slot for insertion of keyed features on a mating lattice member. Each of the plurality of structural joints are configured to facilitate rotation of the mating lattice member, semi-permanently holding the mating lattice member in place with an electro-permanent magnetic (EPM) retaining device. 
     In another embodiment, a system includes a lattice joint housing and a plurality of structural joints. Each of the plurality of structural joints have a side entry slot for insertion of keyed features on a mating lattice member. Each of the plurality of structural joints are configured to facilitate rotation of the mating lattice member, semi-permanently holding the mating lattice member in place with an EPM retaining device. The system also includes a wiring harness connecting the embedded EPM with one or more electrical contacts. The one or more electrical contacts provide a current path from an external source, such that a current is routed from the one or more electrical contacts to wiring harness and embedded EPM to activate or deactivate embedded EPM. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the advantages of certain embodiments of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. While it should be understood that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
         FIG. 1  is a diagram illustrating a lattice for space structures, according to an embodiment of the present invention. 
         FIG. 2  is a diagram illustrating a top view of a structural joint of lattice, according to an embodiment of the present invention. 
         FIG. 3  is a diagram illustrating a side view of a structural joint of lattice, according to an embodiment of the present invention. 
         FIG. 4  is a diagram illustrating a front view and side view of a structural tube (or structural rod), according to an embodiment of the present invention. 
         FIG. 5  is a diagram illustrating a front view and side view of an insert for the tube of  FIG. 4 , according to an embodiment of the present invention. 
         FIG. 6  is a diagram illustrating a front view of an insert for tube with an embedded anti-rotation EPM, according to an embodiment of the present invention. 
         FIG. 7  is a diagram illustrating a front view of a structural tube (or structural rod) with integrated electrical contacts, according to an embodiment of the present invention. 
         FIG. 8  is a diagram illustrating a top view of a structural joint with an embedded ferromagnetic plate, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Some embodiments pertain to lattices that maximize strength-to-mass ratio, facilitating large yet low-mass structures in space. These lattices give the ability to build larger structures in space (for solar sails, solar farms, etc.) at a drastically reduced cost than available by the current state of the art. The lattices also have the ability to reconfigure the space structure to adapt to changing mission requirements. The lattices include structural joints that are non-permanent in so far that the structural joints can be repurposes for new mission requirements and enable new mission concepts. Because the lattices utilize EPMs that use 40-100 mW per structural joint, the structural joints use approximately 7,000 times less power than current state of the art-welding techniques. 
       FIG. 1  is a diagram illustrating a lattice joint  100 , according to an embodiment of the present invention. In an embodiment, lattice joints  100  include a lattice joint housing  101  and a plurality of structural joints  102 . These structural joints  102  are connection points for other structural members of the lattice. Structural joints  102  have a side entry slot  104  for the insertion of keyed features on the mating lattice members. Keyed features may be defined as a two-piece locking system where each part forms a portion of the lock. The keyed features allow the parts to be connect with little or no force. Once the parts are rotated into the locked position, the parts can withstand high tensile or compressive loads. Structural joint  102  in some embodiments allows the mating lattice member (see  FIG. 4 ) to be rotated and semi-permanently held in place with an EPM retaining device (not shown). Further, structural joints  102  are mechanically coupled to lattice joint housing  101  by mechanical fasteners, adhesive or other physical bonding technique. 
       FIG. 2  is a diagram illustrating a top view of a structural joint  102  of lattice  100 , according to an embodiment of the present invention. 
     In an embodiment, structural joint  102  is composed of several features. For example, structural joints  102  have a side entry slot  104  for the insertion of the keyed features on the mating lattice members. Structural joints  102  incorporated a keyed type retaining feature  202  that allows a mating member of the lattice to be rotated after being inserted in entry slot  104 . The mating member of the lattice may be defined as any structural element or device that has the keyed feature required to mate with structural joint  102 . Retaining feature  202  holds the mating member axially in place and reacts the axial loads to lattice joint housing  101 . Structural joint  102  contains clearance holes  204  for mechanical fasteners that mechanically couple the structural joint  102  to the lattice joint housing  101 . 
       FIG. 3  is a diagram illustrating a side view of a structural joint  102  of lattice  100 , according to an embodiment of the present invention. 
     In an embodiment, structural joint  102  is composed of a base plate  302  and lock plate  306 . Base plate  302  and lock plate  306  are coupled in a manner that joins plates  302  and  306  in a manner that prevents disassembly commonly referred to as an inseparable assembly. Alignment features on base plate  302  and lock plate  306  align slot  104  features. 
       FIG. 4  is a diagram illustrating a front view and side view of a structural tube (or structural rod)  400 , according to an embodiment of the present invention. In an embodiment, structural tube  400  is composed of two inserts  404  and one tube  402 . Inserts  404  are bonded to tube  402  with adhesive or another bonding agent. 
       FIG. 5  is a diagram illustrating a front view and side view of an insert  404  for tube  402  of  FIG. 4 , according to an embodiment of the present invention. In an embodiment, insert  404  has key feature  502 , which mates with retaining feature  202  of  FIG. 2  to axially lock structural tube  400  to structural joint  102 . 
       FIG. 6  is a diagram illustrating a front view of an insert  404  for tube  402  with an embedded anti-rotation EPM  602 , according to an embodiment of the present invention. In an embodiment, insert  404  has an embedded EPM  602  that clamps to ferromagnetic plate  802  (see  FIG. 8 ). A wiring harness  604  connected to embedded EPM  602  provides a current path for activating and deactivating embedded EPM  602 . Wiring harness  602  is routed through the base of insert  404  into tube  402 , in some embodiments. 
       FIG. 7  is a diagram illustrating a front view of a structural tube (or structural rod)  400  with integrated electrical contacts  702 , according to an embodiment of the present invention. In an embodiment, electrical contacts  702  are connected to the wiring harness  604  of  FIG. 6 . Electrical contacts  702  in some embodiments provide a current path from an external source (not shown) through electrical contacts  702 . The current may be routed from electrical contacts  702  to wiring harness  604  and embedded EPM  602  to activate or deactivate embedded EPM  602 . 
       FIG. 8  is a diagram illustrating a top view of a structural joint  102  with an embedded ferromagnetic plate  802 , according to an embodiment of the present invention. 
     In an embodiment, structural joint  102  has an embedded ferromagnetic plate  802  that provides a magnetic flux path for embedded EPM  602  of  FIG. 6 . The flux path creates a clamping force between magnetic plate  802  and embedded EPM  602  to prevent the rotation of structural tube  400  while embedded EPM  602  is activated. When embedded EPM  602  is deactivated no clamping force is generated and structural tube  400  is free to rotate. 
     Some embodiments generally pertain to a system that includes a lattice joint housing and a plurality of structural joints. Each of the plurality of structural joints have a side entry slot for insertion of keyed features on a mating lattice member. Each of the plurality of structural joints are configured to facilitate rotation of the mating lattice member, semi-permanently holding the mating lattice member in place with an EPM retaining device. The system also includes a wiring harness connecting the embedded EPM with one or more electrical contacts. The one or more electrical contacts provide a current path from an external source, such that a current is routed from the one or more electrical contacts to wiring harness and embedded EPM to activate or deactivate embedded EPM. 
     It will be readily understood that the components of various embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments, as represented in the attached figures, is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. 
     The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, reference throughout this specification to “certain embodiments,” “some embodiments,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in certain embodiments,” “in some embodiment,” “in other embodiments,” or similar language throughout this specification do not necessarily all refer to the same group of embodiments and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
     It should be noted that reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
     Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
     One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations which are different than those which are disclosed. Therefore, although the invention has been described based upon these preferred embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.