US 3727356 A
A prefabricated structure constituting at least the major portion of a body formed of 12 hyperbolic paraboloidal panels respectively secured together at their edges, each panel having four equal edges enclosing substantial right angles and having a diagonal whose length is substantially equal to four-thirds the length of the panel edge, the ratio of the elevation of the panel to the edge length thereof being substantially equal to 0.44.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Appenzeller Apr. 17, 1973 PREFABRICATED STRUCTURES  Inventor: Ernest Uri Appenzeller, l5 Maharal Street,-Tel Aviv, Israel 22 Filed: Sept. 17, 1968  Appl. No.: 760,188
s2 U.S. Cl ..s2/s1, 52/82 51 Int Cl. ..E04b 1/32 [58 Field of Search ..52/80, 81, 82
 References Cited UNITED STATES PATENTS 2,391,491 6/1959 Richter ..s2/s1 2,995,797 8/ 1961 Hoffmann 3,092,932 6/1963 Wilson ...52/80 FOREIGN PATENTS 0R APPLlCATlONS 695,909 10/1964 Canada ..52/80 1,331,238 5/1963 9 France ..52/81 OTHER PUBLICATIONS Understanding the Hyperbolic Paraboloid by Landela', Architectural Record; July 1958; pages 191-195. Mathematical Models by Cundy QA, 11,C8, 1961 pages 76-79, 86, 87, 116, 117, 120, 121, and 178-181.
Primary ExaminerI-lenry C. Sutherland Attorney-Browdy & Neimark s7 ABSTRACT A prefabricated structure constituting at least the major portion of a body formed of 12 hyperbolic paraboloidal panels respectively secured together at their edges, each panel having four equal edges en closing substantial right angles and having a diagonal whose length is substantially equal to four-thirds the length of the panel edge, the ratio of the elevation of the panel to the edge length thereof being substantially equal to 0.44.
2Clalms,9DrawingFigures PATENTED AFR] 71973 SHEET 1 BF 3 F INVENTORS %M m) ATTORNEY PAIENIEW' 3,727,356
SHEET 2 [1F 3 INVENTOR BY [24% MM "ATTORNEY PATENTEDAPR 1 3', 727, 35s
sum 3 UF 3 I INVENTOR ATTO NEY 1 PREFABRICATED STRUCTURES This invention relates to prefabricated structures and to structural panels for use in their construction.
It is the object of the present invention to provide a prefabricated structure which can be readily and easily assembled from a relatively limited number of constructional panels.
It is a further object of the present invention to pro vide a method of and apparatus for constructing constructional panels for use in constructing the structure.
The invention is based on the discovery that it is possible to construct a body which corresponds substantially to a dodecahedron from 12 similar corresponding panels each of which is constituted as a hyperbolic paraboloidal surface having specific characteristics to be defined below, said body contacting at eight of its 14 corners the inner surface of an imaginary sphere.
For a better understanding of the invention and the manner in which it is to be carried out reference will now be made to the drawings, wherein:
FIG. 1 is a view of one constructional panel in accordance with the invention;
FIG. 2 is a front elevation of a structure formed using the structural panel shown in FIG. 1;
FIG. 3 is a view from FIG. 2;
FIG. 4 shows in perspective view a shaped elongated element;
FIG. 5 shows in an exaggerated form a side elevation of the element shown in FIG. 4;
FIG. 6 is a perspective viewof a composite panel formed of elements as shown in FIGS. 4 and 5.
FIG. 7 is a perspective view of a portion of a shaped panel in accordance with the invention formed of a further form of elongated element;
FIG. 8 is a schematic front elevation of an installation for shaping panels in accordance with the invention, and
FIG. 9 is a cross-sectional view of the installation shown in FIG. 8 taken along the line IX IX after a shaping operation.
Reference will now be made to FIG. 1 of the drawings for a description and a definition of the basic structural panel in accordance with the invention. As seen in the Figure the panel 1 has a hyperbolic paraboloidal shape having four equalsides of length a. The panel 1 is shown as if it were resting on an imaginary flat horizontal surface 2 (shown in broken lines), three corners 3, 4 and 5 of the panel 1 are disposed in contact with the flat surface 2 whilst the fourth corner 6 is raised by an amount h, hereinafter referred to as the elevation of the element.
The parameter b which is the length of the diagonal joining the corners 4 and 5 on'the imaginary flat surface is given by the relationship:
12 panels 1, each as shown in FIG. 1 of the drawings can be connected together (by any suitable means, such as, for example, suitably shaped profile bars), each panel being connected at its four sides to four adjacent panels so as to form an enclosed structure 7 which can be entirely enclosed within an imaginary sphere 8 (FIG. 2) of radius r 2 V b'lb eight corners above of the structure shown in v of the 14 corners of the structure contacting the inner surface of the sphere 8.
Thus, the prefabricated structure 7 of FIGS. 2 and 3 constitutes at least a major portion of a body formed of 12 hyperbolic paraboloidal panels which are secured together at their edges, each panel having four equal edges enclosing substantial right angles and having a diagonal whose length is substantially equal to fourthirds the length of the panel edge. This structure is derived from a 24-sided regular polyhedron, each side of which is a right-angled isosceles triangle, but wherein each pair of adjacent triangles having a common base has been replaced by a hyperbolic paraboloidal surface having four equal sides.
Each of a first pair of opposite corners c of each panel is congruent with two adjacent corners c of two adjacent panels whilst each of a second pair of opposite corners d of each panel is congruent with three adjacent corners d of three adjacent panels. It is found in practice that whilst each comer c encloses an angle substantially equal to 90", each comer d encloses an angle which is slightly less than 90, about 88.5".
As can be clearly seen in FIG. 2 of the drawings the structure can be terminated at any suitable plane by correspondingly cutting the appropriate elements through which this plane passes. In point of fact the level 9 forms the lower limit of the structure the missing portion of the whole structure being shown in dotted lines.
It will be appreciated that the structure can be terminated at any suitable plane or series of planes so as to form a structure of any required height and shape.
The size of the structure obtained is determined by the size of the sides of the panels.
As seen in FIG. 2 of the drawings one of the panels is provided with a door hole 10 which can be previously formed in any appropriate panel.
The panels themselves can be formed of any suitable material such as, for example, a thermoplastic material, wood or metal which lends itself to shapinglThus, the elements can be pressed out of metal sheets into the required hyperbolic paraboloidal shape or, alternatively, they can be press-molded in plastic form.
Reference will now be made to FIGS. 4 and 5 of the drawings which illustrate an elongated element for use in constructing a structural panel in accordance with the invention. As seen in these Figures, the element which, in the case of the present embodiment, is formed of plywood, comprises two similar overlapping portions and 1 lb bonded together by a suitable adhesive. These superimposed portions are introduced into a press with the adhesive located between successive pairs and when the bonding adhesive has still not set the elements as a whole are given the required hyperbolic paraboloidal shape after which the adhesive is allowed to set, the elements thereupon retaining this shape. The elements can then be coupled together at their overlapping edges by any suitable means such as bonding, riveting or the like.
The elements shown in FIGS. 4 and 5 of the drawings acquire the required hyperbolic paraboloidal shape by being given a twist in a particular sense. If now a panel 12 is constructed from profiles which have been twisted in an opposite sense and the two elements 12a and 12b thus formed are superimposed and bonded together as shown in FIG. 6 of the drawings, a composite panel 12 of very considerable strength is obtained.
Whilst the invention has so far been described with reference to panels formed of two-piece elements which are shaped and bonded together, the bonding succeeding in retaining the desired shape, a panel formed of single piece elements is shown partially in FIG. 7 of the drawings. The panel is formed of hollow elements 13 formed by extrusion of a suitable plastic material. One longitudinal end of the element 13 is provided with an elongated dovetail groove 15. Such an element 13 can be given the required shape during extrusion itself. The interengagement of successive elements 13 so shaped leads to the production of a suitably shaped panel. On the other hand, substantially planar elements 13 of the kind shown in FIG. can be coupled together so as to form an initially planar panel which is then subjected to required shaping under heat and pressure.
It will be realised that the element shown in FIG. 5 can equally be made of any material such as aluminum which lends itself to extrusion.
Equipment for imparting the required shaping to initially planar panels of the kind shown in FIG. 7 is illustrated schematically in FIGS. 8 and 9 of the drawings.
The equipment consists of an installation 17 comprising a lower support beam 18 which is essentially of channel-shaped cross section and an upper turning beam 19 also of channel-shaped cross section. The open longitudinal ends of the beams 18 and 19 face each other whilst their side ends are closed. The lower support beam 18 is mounted on a support frame 20 consisting of horizontally extending beams 21 upon which the lower support beam 18 rests and a pair of vertical beams 22 secured to the horizontal beams 21 and strengthened by means of angular struts 23. The upper ends of the vertical beams 22 carry an upper beam, displacing and turning structure 24. This structure 24 is coupled to the upper turning beam 19. The structure 24 consists of a pair of hydraulic or pneumatic cylinder mechanisms 25, having piston rods 26 coupled to the upper turning beam 19. Thus, depending on the direction of inflow of hydraulic fluid into the mechanisms 25, the upper turning beam 19 can be raised or lowered as required into and out of a predetermined position. The structure 24 furthermore includes a beam turning mechanism which consists of a worm drive 27 arranged to be driven by means (not shown) and having a driven axle 28 which is coupled to the upper turning beam 19.
An air compression pump 29, driven by a motor 30 has its outlet 31 coupled via an air heating conduit 32, having an electrical heating element 33, to the input of an air distributing pipe 34 which extends through the lower support beam 18 and is provided with air outlet apertures distributed along the length thereof. As can be seen in the drawing the air distributing pipe 34 is of conical shape, tapering gradually from the end adjacent the pump 29. The pipe is given this tapering shape so as to ensure a substantially uniform air flow through the apertures alo%the entire length thereof. The outlet 35 o the pump via a flexible conduit 36,
15 coupled, with an outlet of the otherwise sealed upper turning beam 19. I
In operation a plurality of substantially planar panels 37 constituted of hollow elements of the kind shown in FIG. 7 of the drawings, is introduced into the installation. The lower ends of the panels are located within the support beam 18 above air distributing pipe 34 whilst the hydraulic cylinders are so arranged that the upper turning beam 19 is in a raised position. When the panels are all suitably located with respect to the lower support beam 18, the hydraulic cylinders are actuated so as to lower the upper turning beam 19 into a position where the upper ends of the panel 37 project into the beam 19. In this way the panels are firmly and air tightly clamped to the installation. The motor 30 and heating element 33 are actuated and hot air is passed continuously via the air distributing pipe 34 through the hollow panel elements and out of the beam 19 and the flexible conduit 36. When the passage of the hot air has proceeded for a length of time sufficient to render the panels slightly flexible, a drive is imparted to the worm drive 27, as a result of which the upper beam is rotated by a predetermined amount (as shown in FIG. 9). In consequence the panels are twisted by the same amount thereby imparting to them the required shape. The panels are held in position and cold air is passed therethrough by means of the pump 29 for a time sufficient to allow the panels tovrigidify in their new shape. When the panels have cooled down sufficiently the hydraulic cylinder mechanism is actuated so as to raise the upper turning beam 19 and thereby facilitating the removal of the shaped panels.
With an installation as just described it is possible to impart simultaneously the required shaping to the entire number of panels required to form the subsequent prefabricated structure.
1. A prefabricated structure constituting at least the major portion of a body formed of 12 hyperbolic paraboloidal panels, each said panel having four edges and each said panel being secured to four adjacent panels at its four edges, each of the edges of each said panel being of equal length, each of the four angles of each panel defined by two adjacent edges being substantially a right angle, each panel having a diagonal whose length is substantially equal to four-thirds the length of the panel edge, whereby all adjoining corners of said panels lie along or within the surface of an imaginary sphere.
2. The structure of claim 1 having 14 corners, whereby eight of the corners of said body lie along the surface of an imaginary sphere.
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