Abstract:
A building of geodesic dome type based on a variant of the helix formula and exhibiting the engineering characteristic known as tensegrity. All juncture points are precisely located from the jig for construction. A method of top closure enabling easy construction is included.

Description:
This application is a continuation-in-part of U.S. application No. 891,401 filed May 2, 1986, and now abandoned which is in turn a continuation-in part of U.S. application No. 603,341 filled Apr. 16, 1984, and now abandoned. 
    
    
     CROSS REFERENCES 
     Construction of domes utilizing triangular arrangements of struts or plates is an old technique known generally as &#34;geodesic&#34;. The prior art provides many examples of joining such struts or plates. 
     SUMMARY 
     The building is designed according to a precise mathematical formula from which all points of juncture for struts or plates may be readily determined. The formula is a variant of the helix formula and when it is applied in both a clockwise and counter clockwise manner to the surface of a sphere, ellipse, or such like shape, defines a polygonal grid on the surface. The counter-clockwise spirals from base to zenith are eccentric in that they do not proceed from base to zenith in the same number of degrees as the clockwise spirals. As a result of the eccentricity of the spirals an eccentric pattern of polygons emerges whereby connections of apices across the polygons do not yield symmetric triangles. When connections are made across the polygons in both directions: &#34;horizontal&#34; (that is parallel to the ground), and diagonal, the resultant pattern becomes &#34;geodesic&#34; and gains additional strength from the engineering principle of &#34;tensegrity&#34; which results. 
     By interrupting this pattern at specific points and making calculated adjustments, conventional shaped and sized apertures may be provided for doors or windows, or for panels allowing one or more structures to be easily conjoined. 
     The use of the spiral helix formula also enables the use of a simple building system that facilitates precise construction. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of the dome. 
     FIG. 2 serves as a top view of one half of the dome and serves as an end view in a second configuration. 
     FIG. 3 is an abstraction of one polygon. 
     FIG. 4 is an abstraction of a second polygon. 
     FIG. 5 is a conjunction of half polygons. 
     FIG. 6 is a side view of a second configuration of the dome. 
     FIG. 7 is a side view of a second dome. 
     FIG. 8 is a top view of one half of a second dome. 
     FIGS. 9 through 16 show conjunctions of planar layouts of folded plates. 
     FIG. 17 is a folded plate at the zenith shown in planer layout. 
     FIG. 18 serves as a top view of the construction jig and a side view of the construction jig in the second configuration. 
     FIG. 19 serves as a side view of the construction jig, or as a top view of the construction jig in the second configuration. 
     FIG. 20 shows a top view of a top closure with hexagonal top shape. 
     FIG. 21 shows a side view of a top closure with hexagonal top shape. 
     FIG. 22 shows a top view of a parabolic top closure with triangular top shape. 
     FIG. 23 shows a side view of a parabolic top closure with triangular top shape. 
     FIG. 24 shows a top view of a top closure with a minimum number of juncture points at the top. 
     FIG. 25 shows a side view of a top closure with a minimum number of juncture points at the top. 
     FIGS. 26-28 show additional domes. 
    
    
     DESCRIPTION 
     A roughly spherical shape of the dome is shown in FIG. 1. The dome is designed according to a variant of the helix formula in one of its formats: Z=a&#39;θ, where Z is a height above the base of the dome; a&#39; is a parameter and not a constant; θ is the angle formed by a vector from the center of the dome along the base of the dome to the perimeter of the base as it is rotated from its initial position in an ever widening arc. The helix formula in any one of its formats described above may be modified by the use of a series of numbers which increase in size in some regular manner. Each level of closure will be assigned a number from the series to represent the number of juncture points at that level. All juncture points will be knit together in some regular way by the application of a pattern of arrangement of the structural members characterized by a pattern of lines and triangles connecting juncture levels, where the lines alternate with triangles in some regular way. No arrangement of lines and triangles based upon a series was used to effect top closure of the dome of FIG. 1, but rather all helical spirals begun at the base of the dome have been allowed to proceed to the zenith in uninterrupted manner. Two sets of nine struts or plate edges shown in bold lines follow the steeper helix path from base to zenith proceding from left to right. Two sets of nine struts or plate edges shown in bold lines follow the shallower spiral helix path from base to zenith proceding from right to left. All these bold lines intersect to form the polygon with apices A, B, C, D, and with &#34;midpoint&#34; E. This polygon is bisected by the line AEC in the &#34;horizontal&#34; direction. The &#34;midpoint&#34; of the polygon at E and hence the whole polygon is considered to be at the fourth &#34;horizontal&#34; level from the base as indicated by the numeral 4 at the side of the drawing on the left, where the base is designated number 0 and the zenith is designated number 9. 
     A top view of one half of the same dome is shown in FIG. 2. The same bold lines trace the same spiral helix paths and intersections outlining the same polygon at level four. The spiral nature of the helix paths is more easily seen in this top view where only the main helical paths are shown. The spirals are shown moving in the opposite direction to illustrate that the direction may vary. 
     FIG. 3 abstracts the polygon designated ABCD in FIG. 1. Point E will be on the same circumscribed sphere containing points A, B, C, and D as well. When the connection is made across the polygon from point A to point C passing through point E a &#34;horizontal&#34; slice is achieved since points A, E, and C will be at level 4, at which level the entire polygon is considered to lie. There are twelve similar polygons at level four and at every other level except the zenith, and the base polygon which is sliced in half &#34;horizontally&#34; leaving only the top half. 
     FIG. 4 abstracts the polygon designated FGHI in FIG. 1. Point J is the &#34;midpoint&#34; of the polygon and lies on level 3. The connection FJH is a &#34;horizontal&#34; slice at level 3 with all points being at level 3. FIG. 5 shows the juncture of the polygon shown in FIG. 3 with the upper &#34;half&#34; of the polygon shown in FIG. 4. These two polygonal segments span the distance between level 3 and level 4. Line AD and line GH are identical segments of the two spirals proceding from base to zenith, from right to left, or clockwise as shown in bold lines in FIG. 1. Thus, the segment shown in FIG. 5 also spans the distance between spirals as well as levels. Twelve such segments would completely cover the surface of the dome between level 3 and 4. FIG. 12 corresponds to FIG. 5 except that flanges have been added to facilitate construction. FIG. 12 shows the connection of the two polygonal folded plates being made from point 3 to 4 by abutting the end part of each plate. To complete the juncture each flange would be bent along the line 3 to 4 and folded inward toward the center of the dome along lines DC and FG. 
     FIG. 9 through FIG. 17 show the plates necessary to build one twelfth part of the dome proceding from base to zenith along the shallow path between the two helix paths from right to left, or clockwise, like those shown with bold lines in FIG. 1. FIG. 9 shows four triangles grouped two triangles at a time into two folded plates with construction flanges all around, and abutted together at the juncture of two construction flanges designated 0 to 1 in the &#34;diagonal&#34; direction from left to right. All apices designated 0 are at the base of the dome and all apices designated 1 are at the first level of construction. Each of the two plates shown in FIG. 9 are creased in the center along the diagonal lines 0 to 1 running diagonally from right to left. The result of creasing the plates is to increase their strength and create plates which are dished out, that is concave to the center of the dome. The construction flanges are angled at the ends so that the end edges point toward the center of the dome when they are folded toward the center. When the dome is assembled by joining all the flanges together, the joints formed by the polygons will be tight. All points designated 1 in FIG. 9 will be joined to all points designated 1 in FIG. 10 to complete the first &#34;course&#34; of eight &#34;courses&#34;. Twelve sets of four triangles such as those shown in FIG. 9 when joined together and then joined to the similar flanges in FIG. 10 will complete the first &#34;course&#34;, and so on to the top following the path of the spiral having the longer shallower path. Twelve such completed spirals form the entire dome. Construction would proceed by laying each &#34;course&#34; of twelve groups of four triangles around the dome before starting the second &#34;course&#34; represented by the four triangles of FIG. 10. When the triangles of FIG. 10 are joined to the triangles of FIG. 9 twelve times around the dome the second &#34;course&#34; is layed, and so on to the zenith. By laying &#34;courses&#34; the level of the &#34;courses&#34; may be checked as construction proceeds in much the same manner as laying bricks. In this instance the &#34;bricks&#34; are folded plates but the result &#34;course&#34; by &#34;course&#34; is similar to laying brick, except that the wall/roof is spherical like that of an igloo. 
     Alternatively, construction could proceed using struts. In this method the &#34;horizontal&#34; struts would be mitered so each mitered joint pointed to the center of the dome at the appropriate height on a plane above the center. At each &#34;course&#34; the &#34;horizontal&#34; struts linked together form a rough circle. Eight such &#34;circles&#34; would provide the jigs for construction at each &#34;course&#34;. One such jig is shown as viewed from above in FIG. 18 at level 4 of the dome. FIG. 19 is a side view of the same jig. The jigs will be positioned by a scaffold. Each mitered joint of the roughly circular &#34;courses&#34; becomes the point of juncture for diagonal spiral helix struts. Unlike the &#34;horizontal&#34; struts the diagonal struts may be continuous and not mitered but proceed unbroken from base to zenith. Juncture may be accomplished by weaving the crossing diagonal struts alternatively one on the inside of the other as they proceed over nine juncture points from the base to point 8. Only the zenith might use a hub or king post juncture. The struts at the jig may be secured by wrapping and gluing. Juncture at the top need not require disrupting the strut. It is possible for the strut to follow a spiral continuously over the top and down to the opposite side describing an S shaped path uninterruptedly. Greater strength would result if the material is not cut and joined at the top but is overlaid one strut upon another until wrapped and glued. When continuous struts are used in construction a &#34;tendon&#34; of very flexible material would be used to wrap and secure the struts to the jig. This tendon material would follow a spiral path like that described for the folds in the folded plates from the base to the zenith in a direction exactly opposite to the steeper spiral strut. While the strut material will be slightly flexible, the &#34;tendon&#34; material will be very flexible. The jig may be left in and incorporated in the structure or replaced by a &#34;tendon&#34;. 
     The dome shown in FIG. 1 in side view may be built in a second configuration from the same helix formula. In this second configuration the &#34;zenith&#34; is placed at the base rather than the top. The new &#34;zenith&#34; at the base becomes the point of emanation for many of the spirals and is better referred to as &#34;the point of emanation&#34; rather than &#34;zenith&#34; since &#34;zenith&#34; commonly refers to top. Such a point of emanation is matched by another pont of emanation direction across the base for a total of only two. A second configuration of the first dome is shown as an end view in FIG. 2 where point 9 is now at the base as a point of emanation of the spirals. A side view of the second configuration of the dome is shown in FIG. 6 where the two points of emanation are 0 and 18. In this configuration what were &#34;horizontal&#34; jigs now become &#34;vertical&#34; and are represented in end view in FIG. 6 by vertical lines rising from points 1 through 12. As before the eccentric spirals would cross these jigs at specific points determined by the helix formula and may be woven and joined as described for the first dome. The jig shown in FIG. 18 may be taken as a &#34;vertical&#34; jig at points 5 and 13 at the base of FIG. 6 rather than a &#34;horizontal&#34; jig at level 4 of FIG. 1. The base of the jig when considered &#34;vertically&#34; would run across FIG. 18 from point 4 to point 10 and the top of the jig would be at point 7. These points on the jig are shown by numbers 4, 5, 6, and 7 above points 5 and 13 on the base of FIG. 6. FIG. 19 will serve to show the same &#34;vertical&#34; jig from the top with point 4 at the base, point 7 at the top, and point 10 at the base across from point 4. 
     In this second configuration some &#34;steeper&#34; spirals will emanate from a point on the base and traverse the surface &#34;over the top&#34; to terminate at the base on the other side. Such a &#34;steeper&#34; spiral is shown beginning at point 1 and proceeding upward and to the right to the top of the jig at point 7. From that point it would proceed on the other side to terminate at a point opposite point 9 on the &#34;backside&#34; of the dome. The dashed lines of FIG. 6 show a continuation of the &#34;roofline&#34; of the dome apart from the major eccentric spirals shown. 
     FIG. 7 shows a second dome with &#34;courses&#34; a constant number of degrees from one another, as reckoned from the center of the dome, rather than a constant distance from one another as shown in FIG. 1 and FIG. 6. Two bold lines show the steeper and shallower paths. The spirals are eccentric in a similar way to the first dome shown in FIG. 1 and proceed from base to zenith through a different number of degrees. This second dome displays another characteristic: the spirals do not traverse as many &#34;courses&#34;. The number of &#34;courses&#34; may be variable as the second dome serves to illustrate. The second dome displays another characteristic: a closure at the top containing a progressively smaller number of &#34;horizontal&#34; members beginning with &#34;course&#34; six The means for the top closure is abstracted and shown in greater detail in FIG. 20 as a top view and FIG. 21 as a side view, where the basic top hub shape is the hexagon at &#34;course&#34; 7. There are 24 sides to the polygon at &#34;course&#34; 5, 12 sides to the polygon at &#34;course&#34;6, and 6 sides to the polygon at &#34;course&#34; 7. The series used for deriving this result is: 6, 12, 24, . . . , α, where each member is double the previous member, but looking at the matter from the standpoint of approaching the hub the series is used in reverse. Looking at the matter from the hub downward along the surface of the dome, each side of the hub emits a triangle which comes to a point at a point of the polygon below at &#34;course&#34; 6, and each point of the hub emits a line which comes to a point of the polygon below at &#34;course&#34; 6. Then in the next iteration the same process is repeated: each side of the polygon at &#34;course&#34; 6 emits a triangle which comes to a point at a point of the polygon at the base of the top closure at &#34;course&#34; 5 and each point of the polygon at &#34;course&#34; 6 emits a line which proceeds to a point on the polygon below at &#34;course&#34; 5 which is the base of the top closure. The bold lines of FIG. 20 and FIG. 21 trace the path of the helical spiral as it proceeds from a point of the hub top shape designated 7 to a conclusion at point 5 below at &#34;course&#34; 5. A portion of a potential closure proceding further to &#34;course&#34; 3 is shown in the upper part of FIG. 20. This additional portion traces the path of the top closure to &#34;course&#34; 3 and shows the invariant pattern of triangles and lines alternating indefinitely to infinity. The top closure of FIG. 20 and FIG. 21 is a simplification of the one shown in FIG. 7 and FIG. 8 where the angle of rotation of the top closure is the same as that of the shorter strut path and the &#34;courses&#34; of the top closure continue the rotation of the lower &#34;courses&#34; so that &#34;course&#34; 6 rotates with respect to &#34;course&#34; 5 in conformity with the angle of rotation of the shorter strut path and &#34;course&#34; 7 rotates with respect to &#34;course&#34; 6 as well in conformity with the angle of rotation of the shorter strut path. 
     FIG. 22 in top view and FIG. 23 in side view show a different pattern of top closure based on a parabolic curvilinear surface. The helical path derived from the formula: φ=a&#39;θ is shown with bold lines traveling from a triangular top hub shape to the base. In this top closure the Fibonacci series: 3, 6, 9, 15, 24, . . . , α, is used to determine the number of juncture points at each &#34;course&#34; of juncture and each &#34;course&#34; of juncture is set apart from the other &#34;courses&#34; according to the Fibonacci series: 10°, 20°, 30°, 50°, 80°, . . . , α. All these differences are introduced to show the versatility of the procedure in order to demonstrate that it is a general technique and not a particular technique. At all &#34;courses&#34; of this Fibonacci series top closure there will emerge as many triangles from the sides as there are sides to a polygon, but there will be a difference with that emerges from the points: some points will emit lines, but some points will emit triangles. In FIG. 22 this begins to occur at &#34;course&#34; 6 and all subsequent &#34;courses&#34;. The pattern of lines and triangles emerging from all points of all polygons at all &#34;courses&#34; is governed by the Fibonacci series: 3, 3, 6, 9, 15, 24, . . . α, with lines commencing one iteration earlier than triangles. Also, lines always emerge from the points on the polygons where triangles have come to a point after coming down from the &#34;course&#34; above and triangles always emerge from the points on the polygons where lines come to a point after coming down from the &#34;course&#34;  above. It will be seen that this pattern is invariant and proceeds all the way to infinity. 
     FIGS. 24 and 25 show a spherical top closure in top and side view. This top closure has a minimum member of juncture points at the top which are designated numeral 1 in FIG. 24 and when joined produce a line at the top. The same line is seen edge on in FIG. 25 in side view. These cases are shown for the sake of completeness since they constitute minimal conditions. Anything else is of necessity more complex. This closure is a half sphere and has a vertical connector from &#34;course&#34; 2 to &#34;course&#34; 3 which is seen in FIG. 25 in side view and which is seen edge on in the top view at level 2. The Fibonacci series used in FIG. 24 and 25 is 2, 2, 4, . . . , . The presence of six points at the base forming a hexagon occurs only by reason of truncation. The spiral helix: Z=a&#39;θ is also used to locate all juncture points in space, were Z, a&#39;, θ are defined in the same way as before, which has one half the number of &#34;horizontal&#34; members as &#34;course&#34; five, and ending with &#34;course&#34; seven which has half as many &#34;horizontal&#34; members as &#34;course&#34; six. By progressively reducing the number of &#34;horizontal&#34; members it is possible to conclude closure easily at the top with a flat six-sided hub, or with six equilateral triangles as shown in FIG. 8. FIG. 8 displays a top view of one half of this dome showing the major helical paths with the reduced number of &#34;horizontal&#34; members shown with bold lines at &#34;course&#34; 6 and 7. This second dome may be built like the first dome with folded plates, struts, with continuous material following the spiral paths over jigs similar to those in FIG. 18 and FIG. 19, where the jigs are &#34;horizontal&#34;.