The present invention generally relates to deployable triangularly-shaped truss systems, and more particularly discloses triangular truss systems having joints that allow for uniform and synchronous retraction and extension of triangularly shaped truss beams.
There have been many attempts to design a practical, compact, folding or flexible truss system which can transition easily between retracted and extended states when the truss system is situated in varying operating environments. Prior art truss systems were designed to exhibit specific characteristics including low size/volume ratio; high kinematic stability; simplicity and reliability; high compactability; or high structural efficiency in terms of weight, complexity, auxiliary mechanism requirements, manufacturing costs, speed of operation or operating costs. Typically, truss systems disclosed in the prior art lack an optimal combination of features. Further, some prior art trusses have undesirable characteristics including undue complexity; inability to move in a coordinated and synchronous manner; requirements for a dedicated deployer; lack of compactability, reconfigurability, and multi-functional uses; and high costs. Relatively few designs have appeared in the marketplace that have been able to incorporate desirable design features, avoid undesirable features, and reduce the complexity of the chordal and section members of the truss system. Fewer still are capable of multiple uses and of deployment in multiple gravitational or operational environments.
For example, U.S. Pat. No. 3,783,573 to Vaughn (“Vaughn”) discloses many of the desired characteristics listed above but also includes some of the undesirable characteristics. Vaughn discloses frame sets and frame bays in a parallelogram configuration that includes extra chords and members that make the design overly complex, increasing the number of components that could fail to extend or retract. Further, Vaughn discloses that collapsing the structure requires the disconnection of the structural bays from each other and the collapse of each bay separately. Thus, Vaughn's system fails to act in a continuous and synchronous manner.
One advance in the art is represented in U.S. Pat. No. 7,028,442, to Merrifield, (the “442 patent”), the teachings of which are incorporated herein by reference. The '442 patent discloses a deployable square or rectangular configured truss with many desirable characteristics. The '442 patent does not disclose, however, the triangular configuration of the present invention, which possesses distinct characteristics and advantages.
There is a continuing need for improved deployable triangular truss systems that achieve synchronous coordinated motion of all members while extending or retracting, are stable, and do not require dedicated auxiliary mechanisms and structures to function, so that the overall deployable system remains compactable and low in weight, and has both reduced complexity and cost.
Accordingly, the present invention is directed to deployable triangular truss beam systems with orthogonally-hinged folding diagonal members that substantially eliminate one or more of the limitations and disadvantages of the related art.
An object of the present invention is to provide an apparatus and method in which triangular, and double triangular trusses can be expanded from a compact form.
Another object of the present invention is to provide three-dimensional triangular trusses having few complex parts, wherein the trusses can be deployed and retracted in a stable, synchronous manner in a variety of combinations to form load bearing beams, masts, platforms, frameworks or other structures while reducing the number of folding chords and chordal members that are required.
Still another object of the present invention is to provide a means for the formation of either linear or curved triangular trusses, wherein the trusses have rectangular or planar faces useful for optional deployment of panels to serve a specified function.
Yet another object of the present invention is to create a triangular truss configuration which can be erected or deployed readily into curved beams or perimeter trusses, wherein the perimeter trusses can be post-tensioned for preloading and high stiffness without preloading of the individual joints for trusses of linear or curved segments.
It is still another object of the invention to permit triangular truss beams to be mounted side-by-side with a common chord to form a double triangular truss configuration.
When employed in a single embodiment, these objects create a stable triangular truss that achieves a synchronous, coordinated motion of its members while extending and retracting. The triangular truss in such an embodiment also preferably does not require dedicated auxiliary mechanisms to function, and is therefore lower in weight, compactable, and low in both complexity and cost.
These and other objects are preferably accomplished by providing a deployable triangular truss beam with proximal and distal ends, comprising a plurality of framesets, each frameset having a first diagonal side member, a second diagonal side member, and a transverse member, each of said diagonal side members and said transverse member having a first and a second end, said first diagonal side member being hingedly connected at its first end adjacent to the first end of said second diagonal side member at a primary joint and the second end of said first diagonal side member being hingedly connected to the first end of said transverse member at a first secondary joint, the second end of said transverse member being hingedly connected to the second end of said second diagonal side member, at a second secondary joint, a plurality of framebay subassemblies, each framebay subassembly comprising a first and second frameset, one of said framesets being connected to another of said framesets by a diagonal member connecting the second end of said second diagonal member at its connection to the second end of said transverse member to the primary joint of a first frameset, and said one of said framesets also being connected to another of said framesets by a diagonal member connecting the second end of said first diagonal member at its connection to the first end of said transverse member to the last mentioned primary joint thereby forming a framebay subassembly. A plurality of framebays, each framebay comprising a framebay subassembly, is provided having a first primary chord connected to the primary joints of the framesets comprising the framebay subassembly, a first secondary chord connected to the second ends of said first diagonal side members of the first and second framesets comprising the framebay subassemblies at their points of connection to the first ends of said transverse members, and a second secondary chord connected to the second ends of said second diagonal side members of the first and second framesets comprising the framebay subassemblies at their points of connection to the second ends of said transverse members. All of the joints are separable into two interconnected mating parts and have hinge means thereon for folding said chords and said diagonal members from a first deployed position to a second retracted position.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of at least one embodiment of the invention.
In the drawings:
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
Chords A, B and C can be comprised of component members, referred to as primary chordal members 101 (Chord A) and secondary chordal members 102 (Chords B & C). Primary chordal members 101 and secondary chordal members 102 may be compression structures or tension structures depending on the structural needs and compacting requirements of the truss system. Compression chord members may be rigid members that are affixed to the truss after extension or deployment or hinged to fold during truss retraction. Tension chord members can be flexible, hinged, pressure formed or use cables. For the purposes of clarity, it is assumed herein that Chords A, B and C use folding members. However, it should be apparent to one skilled in the art that alternative member arrangements can be substituted therefor without departing from the spirit or the scope of the invention.
Thus, triangularly shaped truss beam 100 is shown in
In
As shown in
Transverse members 106 (
In an alternative embodiment, as seen in
Secondary joints 125B and 125C may also optionally have preloaded features to enable higher stiffness with zero free play. During extension, the triangularly shaped bays preferably remain aligned to each other by the action of the joints, as described below. In this embodiment, the hinge axes of secondary joints 125B and 125C are orthogonal with respect to primary chordal members 101 and secondary chordal members 102 when comparing truss beam 100 in its retracted and deployed states. The use of compression chordal members permits bidirectional beam moment loading.
As seen in
Secondary joints 125B and 125C can connect to other components via lugs or equivalent connectors (e.g., an end frame or mount structure). The connectors preferably provide a hinge pin connection for the longitudinal chordal members such that, when truss beam 100 is in an extended position, the joint hinge pins in each chord are coplanar and lie on the chordal axis as discussed in Merrifield U.S. Pat. No. 7,028,442. Thus, 2 framesets form a frameset subassembly and the addition of Chords A, B & C to a plurality of frameset subassemblies form a framebay such as shown in
In its basic form the invention can be used as a beam, mast, or the framework for a wide variety of applications in low and zero gravity environments and at-normal gravity. As a beam, it may be cantilevered or may be supported or mounted at each end of the beam. As a mast, it is may be base-mounted with support from guy cables or equivalent. The truss system may also be used as the framework for larger structures that may be affixed to the truss beam.
The truss system can use power actuated folding chordal members to cause the continuous, synchronous motion of the truss system during extension and retraction. Hinged chordal members may also lock passively during extension of the truss system. The locking may be accomplished by a spring lock or equivalent manner. A minimum amount of force may be required to cause the unlocking and initial rotation of the joints prior to retraction of the full assembly. For a fully automated or semi-automated operation, there may be a need for actuators whose selection will be dependent on the specific requirements of a given truss beam application.
In some embodiments, if gravity loading is not present or if the truss frames are supported by rollers or equivalent, a method of deployment may include the application of an axial force at the end frame. The axial force will be used to extend or retract the truss system. At full extension of the truss system, the chordal members, if hinged, are spring locked. When a truss system is fully extended in the deployed position, for the system to retract, any hinged or locked chordal members need to be unlocked and given an initial force.
When extending and retracting the truss system on level or inclined surfaces, low friction caster wheels attached to the primary hinge joints may be used to support the truss frame. If there is no support surface to support the truss system, various cable and winch mechanisms may be utilized to aid in deployment and retraction of the truss system.
Truss systems may also be designed to cover a span, wherein multiple truss systems are configured having at least two separate trusses located at opposite ends of the span. Each truss deploys and extends from their side across the span. Once the chordal members lock, the ends of each truss maybe aligned and a locking mechanism located at the ends of each truss will fasten together the two trusses across the span.
As seen in
Primary joint 120 is shown in
Fitting half 605 is hinged to an identical fitting half having diagonal connector ends 601, 602 extending outwardly at an angle as shown. Chordal end fitting 603 is pivotally connected at pivot pin 611 (
As seen in
Secondary joint 125B is shown in
Secondary joint 125C is shown in
Folding hinge 111 is shown in
The triangular truss beam 100 of
The triangular truss beam described herein may be uniquely derived from the patented basic square/U-shaped truss beam in U.S. Pat. No. 7,028,442 ('442 patent), the teachings of which are incorporated herein by reference.
Thus, as seen in
A retracted triangular truss bay is shown in
Thus, the invention herein expands the utility of the basic invention in the '442 patent by enabling simplified formation of either linear or curved structures, where the structures have a wide face useful for optional deployment of flat panels to serve a specified function.
A truss geometry is created which can be readily used to efficiently form planar area platforms by lateral mating of linear trusses.
The number of folding chords required is minimal. A perimeter truss as seen in
Truss configurations are created which can be erected/deployed readily into curved beams or perimeters. As closed perimeters, they can be post-tensioned for joint preloading without preloading of individual joints as for trusses of linear or open curved segments.
Referring to
The joint 120, shown in
The joints 125B replace the primary joints in the truss in the patent '442 . They have two hinged fittings, which can be derived geometrically by splitting the hinged fittings of joints 120 down their centerlines. These joints are defined as including the end fittings of the chordal struts and transverse members. The latter incorporate spherical bearings to allow 2-axis freedom about the main hinge pin of the hinged fittings when the truss folds. These hinged fittings each connect to a side diagonal, through a rotational joint to permit the necessary orthogonal joint action as in the '442 patent. The diagonals fold parallel to each other as shown in
The joints 125C are shown in
For the dual truss embodiment of
As shown in
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
This application claims the benefit of and priority to U.S. Provisional Application Ser. No. 60/711,670, filed Aug. 29, 2005, the contents of which are incorporated by reference herein in its entirety.
Number | Date | Country | |
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60711670 | Aug 2005 | US |