Patent Grant
10494806
Not applicable.
No federal government funds were used in researching or developing this invention.
Not applicable.
Not applicable.
The invention relates to a flexible space frame, the components thereof and a method of construction.
The present invention is a light, strong and flexible space frame and a versatile method for construction of such a frame.
Modular framing systems applied to aerospace vehicles and structures, as well as to terrestrial construction and robotics, are known. For example, U.S. Pat. No. 1,410,876 to Bell teaches kite-shaped tetrahedral structures to be interlocked for an aerial vehicle or structure. More recently, U.S. Pat. No. 5,097,645 to Sanderson.
Space frames are useful in that they provide a construction method that is atypical of rectilinear frame construction of many typical buildings and structures. Space frames provide a light weight easy to construct structure which is aesthetically pleasing and multifunctional. They are often used for roof top frames, pergolas, and venues which want to portray a cosmopolitan or space age ambiance.
Currently known space frame models require the use of specially designed struts made of metallic alloys which are rigid and thus do not allow for a freedom of movement within the assembled frame in reaction to airflow or other stresses. These frame components are often also comprised of expensive metals and pose difficulties in distribution that lead to logistical challenges and increased expense.
As is well known in the fields of civil and industrial engineering, the overuse of rigid materials makes the resulting products, whether buildings, vehicles or machines, susceptible to fractures and failure when environmental stress is applied, whether from wind, water, torsion, acceleration or otherwise. The degree and location of flexibility within a structure is determined by the architect and/or engineer. In modular construction, the best practice is to provide the designer with choices as to which points within the larger design may be either flexible or rigid, allowing for a structure that can best respond to anticipated types environmental stress. For example, a given structure can remain rigid when force is applied from one direction, but flexible when force is applied from a different, or even opposite, direction.
Currently known space frame technology lacks a combination of rigid and flexible components whereby a force applied to a rigid component can be transferred to flexible components to be distributed evenly throughout the structure. The invention as taught herein addresses this lack of flexibility.
In a preferred embodiment, a cross-shaped member for constructing a space frame, such member comprising a cross-piece with four equidistant arms, each extending outward towards a distal end, each end comprising an integrated connector piece designed to interlock with other connector pieces, each such connector piece comprising a distal connecting pin with a ledge and an angled edge for locking, a distal connecting hole, a short side alignment pin, a short side alignment hole, a tall side alignment pin, a tall side alignment hole a channel and a semicircular protrusion, wherein each pair of connector pieces interlock using the side alignment pins and side alignment holes to form a connector piece assembly with two distal connecting pins and two distal connecting holes.
In another preferred embodiment, the cross-shaped member as described herein, wherein the cross-shaped member is constructed of a durable yet flexible material from the group comprising shape memory metal alloys, shape memory polymers or shape memory copolymers.
In another preferred embodiment, the cross-shaped member as described herein, comprising a cross piece and four arms made from the group consisting of shape memory alloys, shape memory polymers or shape memory copolymers, and four connector pieces made of a non-shape memory metal alloy or polymer.
In another preferred embodiment, the cross-shaped member as described herein, wherein the cross-shaped member is made of injection-molded plastic.
In another preferred embodiment, the cross-shaped member as described herein, wherein the cross-shaped member is manufactured by three-dimensional printing.
In another preferred embodiment, the cross-shaped member as described herein, wherein the connector pieces interlock using only applied pressure to snap together.
In another preferred embodiment, a space frame comprising a plurality of frame units wherein each such unit is connected by a snap fit connection between the units' respective connector piece assemblies, such units taken from the group consisting of: (i) a spherical unit comprised of six cross-shaped members as described herein, wherein each connector piece is interlocked with another connector piece to form twelve total connector piece assemblies and six convex surfaces, wherein each pair of connector pieces interlocks using the distal connecting pins and distal connecting holes to form a connector piece assembly with two tall side pins, two short side pins, two tall side holes and two short side holes; and (ii) a reverse unit wherein each cross-shaped member is inverted, yielding six concave surfaces, wherein each pair of connector pieces interlocks by inserting the side alignment pins into the corresponding side alignment holes to form twelve connector piece assemblies, each connector piece assembly locked with two overlocking blocks and comprising two distal connecting pins and two distal connecting holes.
In another preferred embodiment, the space frame as described herein, comprising a plurality of tetrahedral units, with a spherical unit arranged inside of each tetrahedral unit.
In another preferred embodiment, the space frame as described herein, comprising a plurality of octahedral units, with a spherical unit arranged inside of each octahedral unit.
In another embodiment, a method of manufacturing the space frame as described herein, comprising the steps of: (1) making the cross-shaped members as scribed herein by fashioning each cross piece and four arms from the group consisting of shape memory alloys, shape memory polymers or shape memory copolymers, and four connector pieces made of a non-shape memory metal alloy or polymer; (2) creating frame units taken from the group consisting of: (i) a spherical unit comprised of six cross-shaped members, wherein each connector piece is interlocked with another connector piece to form twelve total connector piece assemblies and six convex surfaces, wherein each pair of connector pieces interlocks using the distal connecting pins and distal connecting holes to form a connector piece assembly with two tall side pins, two short side pins, two tall side holes and two short side holes (ii) a reverse unit wherein each cross-shaped member is inverted, yielding six concave surfaces, wherein each pair of connector pieces interlocks by inserting the side alignment pins into the corresponding side alignment holes to form twelve connector piece assemblies, each connector piece assembly with two distal connecting pins and two distal connecting holes, and finally interlocking the connector pieces with the snap-fit overlay of two overlocking blocks, and (3) connecting each such unit to one or more other units by a snap fit connection between the units' respective connector piece assemblies.
In another preferred embodiment, a node for constructing a space frame, such node comprising two or more helical cross-shaped members, each such member with four arms, wherein each such member comprises one or more grooves allowing two or more such members to be reversibly interlocked at an interface joint and each arm comprises a c-channel cut along the axis, each arm thus accommodating a rod for connecting the node to other nodes.
In another preferred embodiment, the node as described herein, comprising three cross-shaped members with twelve total arms and thereby twelve points of attachment to other nodes.
In another preferred embodiment, the node as described herein, whereby each cross-shaped member is made from the group consisting of shape memory alloys, shape memory polymers or shape memory copolymers.
In another preferred embodiment, the node as described herein, whereby each cross-shaped member is permanently attached using melting, adhesives or similar bonding.
The invention comprises a modular space frame with multiple rigid components tied together using a flexible frame, wherein the flexible structure maintains its strength along the same lines of strength as the rigid structures. A force applied along a vector through the rigid frame will be transferred into the flexible frame and distributed evenly across the flexible frame.
Levels of flexibility and rigidity within the frame can be varied, either by choice of materials or the thickness thereof. Not only can the flexible frame provided act as a hinge or joint, but it can also act as a cushion or shock absorber between two or more rigid components.
This method of flexible space-frame construction allows for the use of a single modular part to construct an entire frame, one embodiment of which is pictured in
Each cross-shaped member snaps in place to other like members by fitting the two connector piece assembly components together. As used in describing the invention, “pins” shall be understood to be protrusions, usually cylindrical, integrated into the larger structure of a cross-shaped member for the purpose of attaching to other such members. The connecting pins of one member align to the holes of the other. The two are then squeezed together and either (1) align the larger components for attachment by a secondary mechanism, such as part 70 pictured in
Six such cross-shaped members can be aligned, bent and connected into a plurality of designs, each comprising a “unit”. Examples of such unit designs are a rough spherical unit 50 with six convex surfaces, a reverse unit 51 with six concave surfaces, an open-topped spherical unit 52.
In the spherical unit example, two spheres can be aligned at any of twelve connector piece assemblies 39, located at intervals around the sphere. These alignment points allow the two spheres to be attached together. By again aligning the pins and the holes, the two units can be brought together. The two spheres can be secured in place by attaching overlocking construction blocks 70 at the point of intersection (see,
This method of space frame construction employs a rigid method of space frame construction in conjunction with and attaches to the flexible frame as described herein above. The disclosed method employs the use of one part repeated many times to produce a structure which is strong, lightweight and rigid. Another cross-shaped member that is different from that used above is used for the manufacture of a 12-pointed (6 channel) star shaped node. In this case, three cross-shaped members, all of the same shape and size, are joined to form one 12-pointed star shaped node. This star shaped node is then used in conjunction with wooden, plastic, metal and/or carbon fiber rods to form up a rigid space frame by the use of snap-fit mechanisms which are integrated into the design. This rigid frame can optionally be constructed without the use of glue, weld joints, non-integrated pins, screws or other permanent fasteners. Each cross-shaped member is made up of two c-channels. The c-channels are designed to allow flexible or semi-flexible rods to be snapped into or inserted from the end into the channel. Typical materials of the flexible or semi-flexible rods would be made up of wood, plastic, metal, fiberglass or carbon fiber, or other, similar materials exhibiting a varied degree of rigidity and durability while also allowing for flexibility. Materials for the flexible or semi-flexible rods will be chosen and/or mixed to account for the degree of flexibility desired and the level of stress expected on a given construction. The purpose of the node, for example as pictured in
Applicant's disclosed manufacturing method prevents the need for a complicated mold and manufacturing processes which can add costs to the end product. Since the final product results in a 12-sided shape, an injection-molding or similar process would require a 12-sided mold and a specialized and complex manufacturing process. Thus, a cost-effective manufacturing process as described herein will have great market utility.
The disclosed method offers simplicity such that unskilled workers will be able to install and assemble the frame quickly and easily. There are few if any tools required for assembly when the units are relatively small in size. As such, units up to a certain size can be assembled without tools, welding or adhesives, and disassembly is similarly simple with few or no tools needed.
Shape memory metal alloys (SMAs) and shape memory polymers (SMPs) are known that would provide the desired flexibility to components of the space frame invention, preferably the cross pieces and/or arms of the cross-shaped members. SMAs such as nickel-titanium, nickel-aluminum, copper-aluminum-nickel, beta titanium alloys such as Ti—Nb, Ti—Mo or Ti—V, beta brass alloys such as Cu—Zn—Al, are currently in use in the industries of medical devices, robotics, industrial design and, increasingly, construction. Flexible space frame components made of SMAs could exhibit either one-way or two-way memory effects. In the latter case, the components could be stored and transported at one temperature with a shape providing for ease of storage and movement, with such components then displaying a different, second shape when deployed at a second temperature, such as the extreme cold of outer space.
Several known polymer and copolymer types exhibit shape memory properties and may be useful for producing cross-shaped members. Probably the best known and best researched SMP is polyurethane polymer, but also known are crosslinked polyethylene homopolymer, styrene-butadiene thermoplastic copolymer, polyisoprene, the class of copolymers including stearyl acrylate and acrylic acid or methyl acrylate, as well as norbornene or dimethaneoctahydronapthalene homopolymers or copolymers, and styrene copolymer.
SMPs and SMAs have been the subject of commercial development in the last 20 years. SMPs derive their name from their inherent ability to return to their original “memorized” shape after undergoing a shape deformation. In the present invention, the use of an SMA or SMP to manufacture the belt-like configurations of cross-shaped members will allow those members to bend, twist or otherwise deform within their unit structures to absorb an application of force that might otherwise damage or destroy the larger frame, but then return to their original configurations to maintain the frame integrity after any such shock occurs.
Construction of Applicant's frame components may occur by use of injection molding, three-dimensional printing, or similar techniques used commercially for metals and plastics.
The final structure can have an infinite arrangement and therefore allow for the final structure to have a plurality of shapes.
One embodiment is a structure is based on a face centered cubic lattice of spheres and a tetrahedral-octahedral honeycomb of straight lattices and an arrangement with the diameter of each node being equal, it forms a space filling arrangement of spheres interconnected with a lattice of tetrahedral-octahedral honeycombs, which can be manufactured with the use of three-dimensional printing techniques. (See, e.g.,
The ease of tool-free assembly means that frame structures may be constructed on-site without the need for large-scale prefabrication, even in difficult environments. This will allow the frames to remain in modular form during transportation, where they can be usefully stacked and stowed. Similarly, the units of the frame may be disassembled by unsnapping, requiring few or no tools. Thus, the ease of maintenance of a frame-on site will be enhanced, as single units may be removed and replaced and entire frames reconfigured with minimal difficulty.
The ease of construction and reconfiguration of a frame structure provides capability to change the frame shape or to change units of one material or type with units of another as needed.
In order to prevent the units of the larger frame from pulling apart, shape memory materials will sometimes be inappropriate for manufacture of the connector pieces. In another embodiment, the connector pieces will be made of a known hard alloy, ceramic, polymer or copolymer, and connected to each arm end via a known process of integration such as via adhesive, welding or similar stress-resistant method of attachment.
If either nitinol or piezoelectric crystals are introduced along one direction of the final structure then the structure can bend with a change in temperature or electrical current. This feature can provide a multitude of applications ranging from lifts, and joints to large mechanical muscles. It is preferred to use piezoelectric crystals within the matrix as a means to introduce mechanical control of the matrix. Piezoelectric crystals are known and used in industry because of their unique capability to change shape, deform, warp, shrink or expand when an electric current is applied. This property of the crystals is not only useful for the purpose of changing shape, in addition the crystals apparently exhibit intense force comparable for their size and weight. So a small crystal can lift several times its own weight without permanent degradation of its structure. On the downside, these crystals have limited movement and shape deformation characteristics which limit their usefulness as mechanical muscles in. However, they have found their way into many other technologies. Presently, they are used in printers, copiers, telecommunications, pneumatics and a variety of other technologies. The present invention introduces a new application for these crystals which will allow their use in mechanical muscles.
The invention can produce a large flexible frame with the use of “sites” throughout its structure. A site is created at any point where flexibility can be observed and where a piezoelectric crystal can be attached between two points. Piezoelectric crystals can optionally be introduced per the designer's requirements. When introduced into the structure, the piezoelectric crystals are attached and secured to the structure. Wires connect the crystals to a power source and a control center wherein electricity can be introduced to the crystals at those locations to where movement is needed. The powered piezoelectric crystal will then pull or push on the frame to initiate a bending, twisting, shrinking or expansion of the entire frame. The resulting structure will have the ability to lift or move a significant amount of mass without the need for complicated and heavy hydraulics, pneumatics, gears, shifters, relays, motors and shafts. Furthermore, the sensitive crystal is protected by the flexible cushioning nature of the frame, so a crystal will not be at significant risk of damage from over applied force.
The resulting frame will now have the properties of being lightweight, flexible, maneuverable, easily constructed, and finally the ability to act as a mechanical muscle. Additionally, because we can introduce rigidity into any part of the frame as we desire the frame can also have the property of being a simulated bone. So, the resultant structure will have system of mechanical muscles along with rigid skeletal system and the ability to attach the two systems together, allowing the complete structure to perform similarly to that of an integrated musculoskeletal system with all the properties thereof.
Electrical power sources for piezoelectric crystals may be taken from known commercial technology, notably alkaline batteries, lithium ion or other known chemical batteries, solar panels or any other known power source that can be sized and mounted appropriately on the frame.
A space frame for use in a space-station could be used as means of storage while at the same time providing protection from the elements of space. For instance, a flexible frame which has the natural shape of a sphere could provide a means of holding an array of spherical tanks, providing compartmentalization similar to that used in large oceangoing vessels. If this array is used to hold water, fuel, and food then the extra mass added to the frame would help protect the space station from the impact of a small meteor or perhaps radiation. If damage did occur it would be localized to a small region which could easily be repaired. Losses would be minor as the lost cargo would be limited to the vessels which were hit while the remaining vessels remain intact. A similar incident to a larger tank would result in a complete loss of the contents of the entire vessel.
The invention as described herein contrasts from known frame technology in that is exhibits a high degree of flexibility along axial lines. For example, the disclosed units will deform to absorb the stress of a force applied axially along one of the connector rods or radially across the frame, before reverting to its original configuration due to its shape memory components. Further, the method of construction differs from known technology in that the cross-shaped members bend like a spring and are attached together at the tips, whereas known designs require slots cut into the base, fasteners like pins, bolts or screws, or similar means of attachment. As such, this frame allows the units of any configuration to be joined directly to each other without the need for connection rods, pins or other separate connecting components. The inherent flexibility of the larger frame will also compensate for any minor misalignments or defects in the components themselves.
Applicant's frame flexibility also allows for the frame to bend while being assembled, further adding to ease of construction. Because this frame utilizes one repeat unit that can be made rapidly, with known techniques, and units can be stowed efficiently and assembled on site, the frame is less costly to manufacture, distribute, assemble and maintain. Additional pieces would require more molds, additional packaging and increase end costs.
The references recited herein are incorporated herein in their entirety, particularly as they relate to teaching the level of ordinary skill in this art and for any disclosure necessary for the commoner understanding of the subject matter of the claimed invention. It will be clear to a person of ordinary skill in the art that the above embodiments may be altered or that insubstantial changes may be made without departing from the scope of the invention. Accordingly, the scope of the invention is determined by the scope of the following claims and their equitable equivalents.
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| Number | Date | Country | |
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| 20190292768 A1 | Sep 2019 | US |
