Abstract
Static tendon attachments for motile tensile truss appliances are described which are simultaneously economic and support full undiminished service lifespans. These attachments impose compliant tendon bending over a substantial curvature, wherein the bending of a tendon follows an in-plane changing direction aligned to a tendon paired non-static pulley or sheave attachment. Attachments for trusses which have platforms which move extensively in three dimensions are described which have only a single rotating axis. Attachments for trusses which have platforms which move linearly, or in a plane, are described which have no moving parts other than the tendon itself. Attachments are presented for trussed platforms having 6 Degrees Of Freedom (6DOF), such as those useful for house 3D cement printers. Alternate attachments are presented for trussed platforms constrained to planar motion such as drop plotters, and in linear movement trusses such as semiconductor FOUP hoists, anti-sway cranes, and elevators.
Claims
1. A linear motion tensile truss assembly comprising: a plurality of frame tendon attachments numbering three or more, at locations fixed in geometric relation one to another; a plurality of platform tendon attachments, of same number, at locations fixed in geometric relation one to another, at locations distinct from the frame tendon attachment locations; a plurality of tendons, of same number, each under tension, and each connecting and pairing a frame tendon attachment to a platform tendon attachment, wherein each frame tendon attachment has one and only one tendon connected thereto, and each platform tendon attachment has one and only one tendon connected thereto, forming tendon attachment frame and platform paired elements; a geometric arrangement of the frame tendon attachment plurality, the platform tendon attachment plurality, and the tendon plurality, such that they form a tensile truss; a length control means controllably extending, or holding at static lengths, or reducing the lengths, of at least all but one of the tendon plurality; electronic control circuitry which responds to input from at least one external stimulus, and interacts at least in part, with the length control means to hold the platform in a static position and static orientation relative to the frame, or to cause movement of the platform relative to the frame substantially without change in orientation relative to the frame, along a linear path between a substantially invariant proximal limit location and a substantially invariant distal limit location, substantially invariant being within location and orientation deviations less than those which result in tendon to attachment fleet angles sufficient to reduce tendon or attachment service lifespan; a plane defined by three points for each of the frame and platform tendon attachment paired elements, those three points being the centroid of the tendon cross section at the extent of that tendon contact to the frame tendon attachment pair member most proximal to the paired platform tendon attachment when the platform is at the proximal limit, and the centroid of the tendon cross section at the extent of that tendon's contact to the platform tendon attachments pair member most proximal to the paired frame tendon attachment when the platform is at the proximal limit, and the centroid of the tendon cross section at the extent of that tendon attachment contact to the platform tendon attachments pair member most proximal to the paired frame tendon attachment when the platform is at the distal limit; at least one of the tendon attachments in at least one of the tendon attachments pairs being a static tendon attachment having a shape such that contact between the tendon and the attachment has a curvature over the contact variance, which is less than a curvature which results in tendon service lifespan reduction, contact variance being that portion of the tendon to attachment contact which varies as the platform translates between proximal and distal limits; at least one of the attachments in at least one of the tendon attachment pairs is a static tendon attachment shaped such that the contact variance occurs over a planar arc, having the centroid of the tendon cross section at the tendon to attachment contact extent closest to the midpoint between the frame and platform tendon paired attachments, travel substantially aligned to the planar arc plane as the platform moves between proximal and distal limits, substantial alignment being within deviations less than those which result in tendon to attachment fleet angles sufficient to reduce tendon or attachment service lifespan.
2. The assembly of claim 1 further comprising: one or more tendon attachments shaped such that the contact variance occurs over an arc of greater than 90 degrees, with the tendon connected to each such tendon attachment having a cross sectional aspect ratio of 1.5 or less, with the travel of the centroid of the each such tendon at the contact closest to the midpoint between the frame and platform tendon attachments pair members being along a helix with the axis of said helix orthogonal to the planar arc plane of the tendon paired attachment when the platform moves between proximal and distal limits.
3. The assembly of claim 1 further comprising: at least one fixture body which has a plurality of attachments formed thereupon.
4. The assembly of claim 1 further comprising: at least one static attachment which has a tendon restraining fairlead which guides the paired tendon onto the attachment when the length control means changes the length of at least one of the tendon plurality causing reestablishment of contact between the tendon and attachment after a slack tendon condition.
5. The assembly of claim 1 further comprising: at least one static attachment which has a recessed groove into which the paired tendon at least partially sits, and which guides the path of the contact variance.
6. The assembly of claim 5 further comprising: at least one static attachment which has a tendon restraining fairlead which guides the paired tendon into the recessed groove when the length control means changes the length of at least one of the tendon plurality causing reestablishment of contact between the tendon and attachment after a slack tendon condition.
7. A planar motion tensile truss assembly comprising: a plurality of frame tendon attachments numbering two or more, at locations fixed in geometric relation one to another; a plurality of platform tendon attachments, of same number, at locations fixed in geometric relation one to another, at locations distinct from the frame tendon attachment locations with fixturing to allow low friction planar platform motion when juxtaposed to a restraining body, or fixturing to allow low friction planar platform orientation change when juxtaposed to a restraining body, or fixturing to allow both low friction planar platform motion and low friction planar platform orientation change when juxtaposed to a restraining body; a plurality of tendons, of same number, each under tension, and each connecting and pairing a frame tendon attachment to a platform tendon attachment, wherein each frame tendon attachment has one and only one tendon connected thereto, and each platform tendon attachment has one and only one tendon connected thereto, forming tendon attachment frame and platform paired elements; a planar restraining body juxtaposed to the platform which interacts with the platform to limit platform motion and orientation changes to a those parallel to the planar surface of the restraining body; a geometric arrangement of the frame tendon attachment plurality, the platform tendon attachments plurality, the tendon plurality, and a restraining body, such that they form a planar tensile truss: a length control means controllably extending, or holding at static lengths, or reducing the lengths, of at least all but one of the tendon plurality: electronic control circuitry which responds to input from at least one external stimulus, and interacts at least in part, with the length control means to hold the platform in a static position and static orientation relative to the frame, or to cause movement of the platform relative to the frame, or to cause orientation change of the platform relative to the frame, or to cause both movement and orientation change of the platform relative to the frame; at least one of the tendon attachments in at least one of the tendon attachments pairs is a static tendon attachment having a shape such that contact between the tendon and the attachment has a curvature over the contact variance, which is less than a curvature which results in tendon or attachment service life reduction, contact variance being that portion of the tendon to attachment contact which varies as the platform moves and reorients conformal to the surface of the restraining body; at least one of the tendon attachments in at least one of the tendon attachment pairs is a static tendon attachment shaped such that the contact variance occurs over a planar arc, having the centroid of the tendon cross section at the tendon to attachment contact extent closest to the midpoint between the frame and platform tendon attachment pair members, travel substantially aligned to the planar arc's plane as the platform moves and reorients, substantial alignment being within deviations less than those which result in tendon to attachment fleet angles sufficient to reduce tendon or attachment service lifespan.
8. The assembly of claim 7 further comprising: at least one static attachment which has a tendon restraining fairlead which guides the paired tendon onto the attachment when the length control means changes the length of at least one of the tendon plurality causing reestablishment of contact between the tendon and attachment after a slack tendon condition.
9. The assembly of claim 7 further comprising: at least one fixture body which has a plurality of attachments formed thereupon.
10. The assembly of claim 7 further comprising: at least one static attachment which has a round cross section outline, that at least one static attachment being either cylindrical or tubular.
11. The assembly of claim 7 further comprising: at least one static attachment which has a recessed groove into which the paired tendon at least partially sits, and which guides the path of the contact variance.
12. The assembly of claim 11 further comprising: at least one static attachment which has a tendon restraining fairlead which guides the paired tendon into the recessed groove when the length control means changes the length of at least one of the tendon plurality causing reestablishment of contact between the tendon and attachment after a slack tendon condition.
13. A motile tensile truss assembly comprising: a plurality of frame tendon attachments numbering three or more, at locations fixed in geometric relation one to another; a platform tendon attachment plurality of same number, at locations fixed in geometric relation one to another, at locations distinct from the frame tendon attachment locations; a plurality of tendons, of same number, each under tension, and each connecting and pairing a frame tendon attachment to a platform tendon attachment, wherein each frame tendon attachment has one and only one tendon connected thereto, and each platform tendon attachment has one and only one tendon connected thereto, forming tendon attachment frame and platform paired elements; a geometric arrangement of the frame tendon attachments, the platform tendon attachments, and the tendon plurality, such that they form a tensile truss: length control means controllably extending, or holding at static lengths, or contracting the lengths, of at least all but one of the tendon plurality; electronic control circuitry which responds to input from at least one external stimulus, and interacts at least in part, with the length control means to hold the platform in a static position and static orientation relative to the frame, or to cause movement of the platform relative to the frame within a three dimensional volume, or to cause orientation change of the platform relative to the frame, or to cause both movement within a three dimensional volume and orientation change of the platform relative to the frame; at least one of the attachments in at least one of the tendon attachment pairs is a static tendon attachment having a rotationally supported shape such that the contact variance occurs over a planar arc on that shape having a curvature over the contact variance, which is less than a curvature which results in tendon service life reduction, with the rotation of the rotationally supported shape having the contact variance curvature aligned to the paired tendon attachment by the force exerted through the tendon, contact variance being that portion of the tendon to attachments contact which varies as the platform moves and reorients within the three dimensional volume.
14. The assembly of claim 13 further comprising: at least one static attachment which has a tendon restraining fairlead which guides the paired tendon onto the attachment when the length control means changes the length of at least one of the tendon plurality causing reestablishment of contact between the tendon and attachment after a slack tendon condition.
15. The assembly of claim 13 further comprising: at least one fixture body which has a plurality of attachments formed thereupon.
16. The assembly of claim 13 further comprising: at least one static attachment which has a recessed groove into which the paired tendon at least partially sits, and which guides the path of the contact variance.
17. The assembly of claim 16 further comprising: at least one static attachment which has a tendon restraining fairlead which guides the paired tendon into the recessed groove when the length control means changes the length of at least one of the tendon plurality causing reestablishment of contact between the tendon and attachment after a slack tendon condition.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0019] FIG. 1 is an exemplary form of an attachment.
[0020] FIGS. 2A, 2B, 2C, 2D, and 2E are cross sections of several attachment embodiments.
[0021] FIGS. 3A and 3B are schematic isometric and perspective representations respectively, of a linear motion triangular polyhedral truss.
[0022] FIGS. 4A and 4B are schematic isometric and perspective representations respectively, of a linear motion triangular prismatic truss.
[0023] FIGS. 5A and 5B are schematic isometric and perspective representations respectively, of a linear motion quadrilateral polyhedral truss.
[0024] FIGS. 6A and 6B are schematic isometric and perspective representations respectively, of a linear motion quadrilateral prismatic truss.
[0025] FIGS. 7A and 7B are isometric and perspective views respectively of attachments with one form of tendon dead end strain relieving termination.
[0026] FIGS. 7C and 7D are isometric and perspective views respectively of attachments with another form of tendon dead end strain relieving termination.
[0027] FIGS. 8A and 8B are perspective views of a tendon terminating, self strain relieving attachment without and with a tendon respectively.
[0028] FIG. 9A is a top-down isometric view of a triangular polyhedral truss.
[0029] FIG. 9B is a top-down isometric view of a portion of the truss depicted in FIG. 9A.
[0030] FIG. 10 is a perspective view of the truss depicted in FIG. 9A.
[0031] FIG. 11 is a perspective view of the truss depicted in FIG. 9A showing the platform at two heights.
[0032] FIG. 12A is an isometric view of a planar motion truss.
[0033] FIG. 12B is a perspective view of the platform in FIG. 12A.
[0034] FIGS. 13A and 13B are isometric views of a planar motion truss with an intermediate tendon necessitating an extend angular attachment.
[0035] FIG. 14 is a perspective view of a castor mounted attachment usable in a 3D motion truss.
[0036] FIG. 15 is an isometric view of the attachment in FIG. 14.
[0037] FIG. 16 is a perspective view of a wire mesh cage type tendon guide added to the attachment of FIG. 14.
[0038] FIG. 17 is a perspective view of a pair of attachments formed on a single body.
DETAILED DESCRIPTION OF THE FIGURES
[0039] FIG. 1 shows an exemplary embodiment of an attachment 10 which has a cross section 11 of a standard wire rope pulley. This cross section has a radius slightly larger than the equiaxed cross section of the tendon extending, said radiused portion extending less than half of the tendon diameter. The radiused section gives way to a straight angled portion, which serves to guide the tendon into the radiused recess. Three bolts 12 are shown indicating that the attachment is a static tendon reeving element.
[0040] FIG. 2 shows cross sections of several embodiments of the present invention. FIGS. 2A and 2B depict standard pulley cross sections, supporting multi strand wire rope 22. The angle 24 is 60 degrees and angle 25 is 45 degrees. The angle 24 supports fleet angles of up to 4 degrees, whereas angle 25 supports fleet angles of only up to 1.5 degrees before service life foreshortening occurs. For this reason, FIG. 2A is the most preferred cross section for tendons with round or approximately round cross sections.
[0041] Section indeterminate extent 26 depicts that the extent of the attachment can vary, having a relatively thin distance as in attachment 10, or extending completely to fill the area subtended by the tendon curvature, as depicted in FIG. 8. FIG. 2C has the equiaxed multifilament wire rope tendon 22 in a recess, without angled guides. FIGS. 2D and 2E show attachments which have non-recessed curvature surfaces against which the tendon bears. In the case where extent 26 is the full radius of the curvature, FIGS. 2D and 2E would be right circular cylinders. In the case where the extend 26 is relatively modest, FIGS. 2D and 2E would be flat rimmed wheels. FIG. 2E is the most preferred cross section for a non-equiaxed tendon 23 conforming to the tape, band, or belt type tendon description.
[0042] FIG. 3A is a top down isometric schematic representation of a trigonal polyhedral linear motion truss. Trigonal because the frame and the platform are triangles. Polyhedral because the three frame 32 bars, the three platform 33 bars, and the 6 tendons 34 to 39, form an octahedron. The anti-alignment of the frame and platform bars gives rise to a 6 pointed star when viewed orthogonal to the direction of platform motion. The tendons 34 to 39 each span between a static attachment of the present invention 10, and a symbolic active tendon span ending unit 30. These active units 30 are able to retract or extend tendon to decrease or extend respectively the distance between the frame and platform. In real world trusses they are often motorized multi wrap sheaves. They can alternately be pulleys with the tendon being reeved there-over to distal take-up pay-out means. The tendons are each dead end at a symbolically represented strain relieving termination 31.
[0043] FIG. 4A is a top down isometric schematic representation of a trigonal prismatic linear motion truss. Trigonal because the frame and the platform are triangles. Prismatic because the three frame 32 bars, the three platform 33 bars, and the 6 tendons 40 to 45, form the shape of a prism.
[0044] The tendons extending from the two ends of any frame bar 32 or any platform bar 33 are nearly co-planar, being offset by only enough to avoid the two tendons rubbing against each other. Active units 30, attachments 10, and strain relieving dead end terminations 31, provide the same functions as in FIGS. 3A and 3B.
[0045] FIG. 5A is a top down isometric schematic representation of a quadrilateral polyhedral linear motion truss. Quadrilateral because the frame and the platform are quadrilaterals. Polyhedral because the four frame 32 bars, the four platform 33 bars, and the 8 tendons 50 to 57, form an shape with more sides than the prismatic form. The anti-alignment of the frame and platform bars gives rise to a 8 pointed star when viewed orthogonal to the direction of platform motion. Active units 30, attachments 10, and strain relieving dead end terminations 31, provide the same functions as in FIGS. 3A and 3B.
[0046] FIG. 6A is a top down isometric schematic representation of a trigonal prismatic linear motion truss. Quadrilateral because the frame and the platform are quadrilaterals. Prismatic because the tendons extending from the two ends of any frame bar 32 or any platform bar 33 are nearly co-planar, being offset by only enough to avoid the two tendons rubbing against each other. These planes are the crystallographic prismatic planes of structure. Active units 30, attachments 10, and strain relieving dead end terminations 31, provide the same functions as in FIGS. 3A and 3B.
[0047] Linear motion of the trussed platforms in FIGS. 3 to 6, relative to their frames occurs when the extension or retraction of the tendons occur in a coordinated manner which causes the rotation and orientation of the platform relative to the frame to remain invariant. One aspect of this is that the isometric views 3A, 4A, 5A, and 6A are identical no matter the extent of their platform to frame distances. Those skilled in 3 dimensional geometry will see this as key in understanding why an attachment with curvature in a single plane is functional for linear motion trusses.
[0048] FIGS. 7A and 7B are an isometric side view and a perspective view respectively of an alternate attachment embodiment 76 with a strain relieving termination 74 able to adjust the length of tendon 22 using the threaded rod and nut assembly 75. The tendon is indicated as continuing up toward the active unit at 70. This attachment embodiment of the present invention has the mandated large radius curvature from location 78 to location 77. Location 78 is the contact separation between the attachment and the tendon when the platform is at the closest design separation between frame and platform. Location 78 corresponds to the least vertical inclination of the tendon. Location 77 is the attachment to tendon contact separation when the platform is at the furthest design separation between frame and platform. Location 77 corresponds to the most vertical inclination of the tendon. For sheave type active units 30 (not shown) this tendon-on-top embodiment is not preferred because a greater portion of the tendon rubs against the angled sidewall in the portion of platform motion where the frame and platform are further apart, corresponding to the attachment higher fleet angle portion of the motion range.
[0049] FIGS. 7C and 7D are an isometric side view and a perspective view respectively of the attachment embodiment 10 mounted proximally to an alternate form of strain relieving tendon termination appliance 79. The appliance 79 supports a fairlead 71 which guides the location of the tendon, but allows the tendon to move along the tendon length. The appliance 79 further supports a dead end clamp 72 which imposes enough axial deformation to resist tendon motion. Appliance 79 supports multiple wraps 73 of the tendon to dissipate the tension in the tendon over the body of the appliance, resulting in only small forces needing to be resisted by clamp 72. As can be seen in FIG. 7D, those applications having tendon 22 comprised of relatively stiff material, such as wire rope, can ensure correct engagement of tendon 22 into attachment 10, by placing strain relieving tendon termination 79 close to attachment 10, and use of fairlead 71 to ensure well aligned tendon 22 egress to attachment 10. Such embodiments can thus foster unaided, automatic recovery from slack tendon 22 conditions.
[0050] FIG. 8A is a perspective view of a cylindrical embodiment of the present invention which has an integral strain relieving tendon termination, shown without a tendon. FIG. 8B is the same embodiment with tendon 22 in place, said tendon shown here in the least vertical attitude. Location 80 is point at which the last contact between the attachment and the tendon if the tendon were to be completely vertical. The span between 80 and groove exit location 84 is straight, and would support the tendon along the entire 80 to 84 distance, if the tendon were to be vertical. The groove extends 90 degrees around the cylinder, from location 80 to location 81, at single depth which provides the invention mandated gentle curvature over the full range of tendon to attachment contact. The groove continues along the far (not shown) side of the cylinder with a gradual increase in radius through location 82 and continuing to location 83, at which the groove is as shallow as is recommended for a single layer sheave. The groove continues around the attachment to provide a guide for multiple strain relieving wraps 73 of the tendon around the attachment. The groove exits the attachment shortly after directing the cable through clamp 72.
[0051] FIG. 9A is an isometric top-down view of a linear motion trigonal polyhedral truss, with sheaves 91 and attachments 10 scaled to have a 25:1 ratio of tendon diameter to curvature around the sheaves and attachments. Nema style motors 92 are shown at an appropriate scale, with the sheaves 91 and motors 92 supported by frame 93. Platform 94 supports attachments 10 and strain relieving tendon terminations 79 of the type depicted in FIGS. 7C and 7D. FIG. 9B is a higher magnification isometric top-don view of one of the sets of tendons 22 paired sheave attachments, that pair labeled as 91B, 92B, 22B, 1013 and 79B. The sheave is shown as having unspooled tendon 22 through one complete revolution, having lowered the platform 94 from the platform to frame closest separation. In this design, that closest separation corresponds to a tendon which is 70 degrees from vertical. At that closest separation, the sheave location 90 is where the tendon has last contact to the sheave, 20 degrees below the sheave top. With the curvature of the attachment 10 aligned with the closest approach sheave contact, and with a sheave diameter 25 times as large as the tendon diameter, the fleet angle on the attachment 10 is an acceptable 1.5 degrees, as shown.
[0052] FIG. 10 is a perspective view of the FIG. 9A truss, at the one sheave rotation unspooled height. Location 101 is the location on attachment 10 where the tendon 22 and attachment 10 make contact closest to the sheave 91 when the platform 94 is at closest separation to the frame.
[0053] FIG. 11 is a perspective view of the FIG. 9A truss from the same vantage point as FIG. 10, with the platform at closest separation to the frame, and with the FIG. 10 platform location shown in dashed line outlines. Location 111 is the location on attachment 1013 where the tendon 22B and attachment 1013 make contact closest to the sheave 91B. The triangle formed by locations 90, 101, 111 define the Plane Of Optimal Reeving (POOR). The most preferred orientation of attachment 1013 is to have the tendon 22B contact attachment 1013 along a curvature within the POOR.
[0054] FIG. 12A is an isometric view of a two dimensionally restrained planar motion truss viewed perpendicular to restraining planar surface 120, over which platform 121 is held in contact or close proximity by gravity, and over which it moves. The surface 120 may be vertical. The surface 120 may alternately be inclined to the vertical in a direction which causes the platform 121 to press against the surface 121. When inclined, the surface must be no more horizontal than as to allow gravity to pull the platform 121 away from the active units 30. Weight 122 is positioned below the attachments 10 to indicate the center of mass on platform 121 is below the contact between tendons 22 and attachments 10. Platform 121 is suspended on attachments 10 from active tendon span ending units 30 with tendons 22 dead ending on strain relieving tendon termination appliances 79. Each active unit 30 has the tendon 22 contact location for closest platform separation the same distance from the planar surface 120 as the tendon 22 contact to the attachment 10.
[0055] FIG. 12B is a perspective view of the platform 121 and the suspending attachments 10 and strain relieving tendon termination appliances 79.
[0056] The appliance depicted in FIGS. 12A and 12B is an exemplary example of why the definition of a tensile truss requires the inclusion of application induced forces in the definition. The appliance depicted has the platform position restrained by being suspended from two and only two tendons, and is further restrained to motions juxtaposed to a planar surface. As such, the assembly conforms to the disclosure truss definition for only those applications wherein any tool carried by the platform induces no torque. The assembly would be a truss for such applications as a pen plotter, an additive application such as a spray painter, or a subtractive application such as a sand blaster.
[0057] FIGS. 13A and 13B are isometric views of a two dimensionally restrained planar motion truss viewed perpendicular to restraining planar surface 120, over which platform 121 is held in contact or close proximity by gravity, and over which it moves. Active elements 30 and attachments 10 must be at the same distance removed from the planar surface. FIG. 13A shows the platform 121 laterally left of the location wherein cable 22A would be vertical. This places the location where contact between attachment 130 and cable 22A separates as on the lower half of attachment 130.
[0058] FIG. 13A shows the platform 121 laterally right of the location wherein cable 22A would be vertical. This places the location where contact between attachment 130 and cable 22A separates as on the upper half of attachment 130. FIGS. 13A and 13B highlight the need for some configurations of two dimensionally restrained planar motion truss to have attachments according to the present invention, which have curvatures extending significantly further than the ? of a circle adequate for linear trusses.
[0059] The appliance depicted in FIGS. 13A and 13B has the platform position restrained by being suspended from three tendons, and is further restrained to motions juxtaposed to a planar surface. As such, the assembly can conforms to the disclosed truss definition for applications when any tool carried by the platform induces torques smaller than those as can be elastically resisted by the tendon plurality. The assembly could be a truss for a rotary carving tool application such as a dental handpiece, a dremel, a woodcarving router, or metalworking spindle in order of increasing torque. Appliances as have more than three supporting tendons, and are restrained to motions juxtaposed to a planar surface could similarly be trusses as defined.
[0060] FIG. 14 is a perspective view of an attachment embodiment for a truss in which the platform moves in three dimensions, and can support platforms with up to 6 Degrees Of Freedom (6DOF). This embodiment is similar to a castor wheel, with the wheel replaced by a curved surface over which a tendon can be bent in response to platform (not shown) height changes. An attachment with this 3D motion conformity can also be required for trusses whose motion is two dimensionally restrained, but the active elements 30 are not at the same distance from the restraining surface, measured perpendicular to said surface, as the attachments. One such 2D non-co-planar application is depicted in European Patent EP2578367A1. The adapter plate 140 would be affixed to either the platform or the frame. Rotating flange 141 is attached to the adapter plate 140 by attachment fixture 142. Rotating flange 141 carries attachment 143 and a tendon terminating strain relieving fixture shown here as a wire rope thimble 147 held by shoulder bolt 147 with attendant ferrule 146.
[0061] 3D motion conformal attachments can also have the rotary motion embodied along the lines of a hinge as opposed to a castor. Such hinged embodiments (not shown) would have rotary support both above and below the curved surface over which a tendon can be bent.
[0062] Preferred embodiments for both the castor and hinge type 3D motion conformal attachments have tendon 22 pass through the center of rotation point 145, with the location 144 of the tendon 22 to attachment 143 separation sufficiently away from the center of rotation as to overcome the static coefficient of friction for rotating flange 141. The most preferred embodiments for tendons with relatively round cross sections are those as have the classic wire rope pulley cross section 11.
[0063] FIGS. 12A, 12B, 13A, and 13B depict a planar surface as the restraining body against which the motion of the platform 121 is juxtaposed. The restraining body could alternately be a smoothly varying surface such as the unidirectionally curved wall of a liquid containing tank, or a bidirectionally curved hull of a ship. Such non-planar surfaces generally would require a 3D motion conformal embodiment exemplified in FIG. 14.
[0064] FIG. 15 is an isometric side view of the castor type embodiment of FIG. 14. The rotary bearing 150 is visible in this view.
[0065] FIG. 16 shows the embodiment of FIGS. 14 and 15 with an attached wire mesh tendon alignment fixture 160, which acts as a fairlead. This serves to guide the tendon 22 onto an appropriate portion of the attachment as tension is restored to the truss after a slack tendon condition. Tendon guiding fairlead fixtures may be needed for any of the linear motion, planar motion, or 3D motion trusses if the use cases experience slack tendon conditions. Attachment fairleads can be useful design elements as they can aid in initial truss reeving.
[0066] FIG. 17 shows an embodiment with two attachments formed on a single fixture body.
[0067] This arrangement could be employed on a planar motion tensile truss as tendons 22 and 1722 are parallel one to another. The attachment shown on the right side of the body is the same embodiment as shown in FIG. 8, with like numbers between 70 and 84 inclusive designating the same features as in FIG. 8. The left attachment has cable 1722 extending off the image at 1770. Left attachment 1772 has the same function as clamp 72. Left attachment 1773 has the same function as strain relieving wrap 73. Left attachment 1780 has the same function as contact variance extreme 80. Left attachment 1784 has the same function as groove termination 84.
[0068] Although illustrative embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments. It will be understood that the particular method and means embodying the invention are shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the scope of the invention.
