Digital Material Assembly By Passive Means And Modular Isotropic Lattice Extruder System (MILES)

Patent metadata

Field	Value
Publication number	US-2017145694-A1
Application number	US-201615035009-A
Country	US
Kind code	A1
Filing date	May 5, 2016
Priority date	May 7, 2015
Publication date	May 25, 2017
Grant date	—

Abstract

A set of machines and related systems build structures by the additive assembly of discrete parts. These digital material assemblies constrain the constituent parts to a discrete set of possible positions and orientations. In doing so, the structures exhibit many of the properties inherent in digital communication such as error correction, fault tolerance and allow the assembly of precise structures with comparatively imprecise tools. Assembly of discrete cellular lattices by a Modular Isotropic Lattice Extruder System (MILES) is implemented by pulling strings of lattice elements through a forming die that enforces geometry constraints that lock the elements into a rigid structure that can then be pushed against and extruded out of the die as an assembled, loadbearing structure.

First claim

What is claimed is:

1 . A method of constructing a lattice structure, comprising:
connecting together along respective nodes tiles formed of a single geometric shape such that the connected tiles enclose a volume, wherein the respective nodes comprise a loop interface feature whereby a node of one tile surrounds at least part of the node of one or more adjacent tiles; and repeating the connecting step by adding new tiles to unconnected nodes of the previously connected tiles to define a lattice volume, such that the lattice volume grows in a single direction along the centroidal axis shared by stacking the tiles; wherein tiles have the property that, once connected together, load paths align directly at the loop interface feature between tiles.

2 . The method of claim 1 , wherein the tiles are triangles.

3 . The method of claim 1 , wherein the tiles assemble into tetrahedra.

4 . The method of claim 2 , wherein the tiles assemble into octahedra.

5 . The method of claim 4 , further comprising assembling the octahedra face to face, and placing the octahedra upon the previous cell, such that only three triangular faces are required to effectively form the eight faces of each octahedron cell.

6 . The method of claim 5 , wherein the octahedron cells are statically and kinematically determinate following Maxwell's stability criterion, each constructed frame consists of six joints (nodes) connected by twelve non-collinear struts.

7 . The method of claim 6 , wherein a node is connected by six noncollinear struts, exactly constraining each node.

8 . The method of claim 1 , wherein the lattice volume comprises a truss structure that forms an exactly constrained, triple, co-directional cross-linked helix that distributes axial loads into transverse loads.

9 . The method of claim 1 , further comprising combining lattice volumes with other lattice volumes to form multiples of connected volumes each along the same axial direction.

10 . The method of claim 4 , further comprising placing the octahedral in an edge connected fashion to form complex multiples of volumes while retaining node connectivity and stiffness.

11 . (canceled)

12 . The method of claim 1 , wherein the tiles have the property that, once connected together, the point of load alignment resides outside the physical volume of the lattice volume as a virtual node through which the loads effectively pass.

13 . The method of claim 2 , wherein a loop interface feature transmits primarily axial loads along struts of a triangle.

14 . The method of claim 1 , wherein once tiles are connected, moment couples transmit through a loop interface feature.

15 . The method of claim 1 , wherein the node from the next placed part locks the previously placed parts together, forming a constrained and load bearing cell.

16 . The method of claim 1 , wherein the alignment of nodes, struts, and loop interface features provide a system where tension and compression of the overall lattice assembly load joints into a stable configuration such that secondary fastener components such as pins, clips, or screws are not necessary.

17 . The method of claim 16 , further comprising inserting secondary fastener components at nodes, whereby redundant connections may protect against unexpected load conditions.

18 . The method of claim 1 , further comprising selecting tiles for the properties that the lattice volume is independent of material modulus of elasticity, where elastic coupling or flexural joints are not required, nor is a secondary fastener required to transmit load.

19 . The method of claim 1 , wherein elastic joints are used to interlock the loop interface features.

20 . The method of claim 1 , wherein the tiles have been produced of one or more of the following: sheet-metal, concrete, formed wood, composites, injection molding, casting, 3d printing, additive manufacturing, or subtractive manufacturing.

21 . The method of claim 1 , wherein tiles feed from one or more of the following: locally in a magazine cartridge, a reel of components, or remotely in a hopper system.

22 . The method of claim 1 , wherein the lattice volume has the property that it can be disassembled in reverse.

23 . An apparatus capable of building a structure by the additive assembly of discrete parts, comprising:
one or more tiles that latch together as they step along a lattice; a plurality of feet on each tile acting as a part placement, parts feeder and error correction mechanism, the feet having features that provide kinematic alignment with each other, passively locating and locking each one to adjacent feet; a single prime mover capable of driving the apparatus through the stepping process; and one from the list of a mechanical timing mechanism or an electrically or hydraulically controlled actuator, to drive the assembly and locking of parts.

24 . The apparatus of claim 23 , wherein once inserted into the mechanism, a new part is placed and an already placed part is locked-onto by an internal feed mechanism, fixing the part to the structure.

25 . The apparatus of claim 23 , wherein a previously placed foot that was also attached to a previous part and adjacent feet takes a next step by releasing, moving through a trajectory to get to the next position.

26 . The apparatus of claim 23 , wherein the single prime mover is a rotary or linear motion device, such as a motor.

27 . An apparatus capable of building a structure by the additive assembly of discrete parts, comprising:
an assembly mandrel head for defining a path that a part tracks along as it is placed or removed from a lattice, wherein a part is fixed in place and fully constrained after the placement of following adjoining parts, the assembly mandrel head comprising a feed direction wherein the trajectory necessary to mate part interfaces is iteratively defined by an interface fixturing geometry as well as by a possible trajectory defined by the assembly mandrel head; whereby a distance constraint between parts define the timing for placement and constraint.

28 . The apparatus of claim 27 , wherein the distance constraint is established by a carrier, such as a belt, cable or chain.

29 . The apparatus of claim 27 , wherein the assembly mandrel head comprises a single degree of freedom to pull the mandrel head along the structure, the single degree of freedom being actuated by one of either external systems or the mass and inertia of the motion of an initial seed assembly sequence, and further where gravity provides a constant pulling force that drives parts through the assembly mandrel head.

30 . The apparatus of claim 27 , wherein the discrete parts are stored in one from the list comprising: a magazine, cartridge, reel or hopper system.

31 . An apparatus capable of building a structure by the additive assembly of discrete parts, comprising:
a rigid intermediary component connected by pivots, configured to compose the discrete parts into a chain and which forms a distance constraint for the discrete parts; and a rack and pinion arrangement of rollers to feed the parts into a lattice, while locomoting along the lattice; whereby the parts rigidly pivot on an integrated carrier as they roll along the rollers, and the arrangement of adjacent rollers connect the chains into volume

Assignees

• Massachusetts Inst Technology

Inventors

• Carney Matthew Eli
• Jenett Benjamin
• Gershenfeld Neil

Classifications

• E04C3/02 Primary

  Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; {Braces}(E04C3/38 takes precedence; for structures characterised by movable, separable, or collapsible parts E04B1/343; {braced purlins E04B7/024}) · CPC title

• E04B1/19 Primary

  Three-dimensional [3D] framework structures · CPC title

• B23P19/04

  for assembling or disassembling parts · CPC title

• B23P2700/01

  Aircraft parts · CPC title

• B64C1/068

  Fuselage sections · CPC title