US3161939A

US3161939A - Composite formwork for casting structural bodies

Info

Publication number: US3161939A
Application number: US138676A
Authority: US
Inventors: Speidel Karl
Original assignee: Futura GmbH
Current assignee: Futura GmbH
Priority date: 1961-01-25
Filing date: 1961-09-18
Publication date: 1964-12-22
Anticipated expiration: 1981-12-22

Description

DEC 22 1964 K. sPElDEL 3,161,939

COMPOSITE RoRMwoRK FoR CASTING STRUCTURAL BODIES Filed Sept. 18, 1961 3 Sheets-Sheet l A kul l/f Dec. 22, 1964 K. sPElDEL 3,161,939

COMPOSITE FORMWORK FOR CASTING STRUCTURAL. BODIES Filed Sept. 18, 1961 3 Sheets-Sheet 2 Dec. 22, 1964 v K. sPElDEL 3,161,939

COMPOSITE FORMWORK FOR CASTING STRUCTURAL BODIES Filed Sept. 18, 1961 5 Sheets-Sheet 3 /NVENOP 3,161,939 CMEBQSHE FRBJIWRK FR {ASTENG SfRUi'ITURlL BGDll Karl Speidel, Kupferzell, Wurtteniherg, fermany, assigner to Futura Ghibli., Glarus, Switzerland, a corporation of Switzeriand Filed Sept.. liti, wel, Ser. No. 138,676 Claims priority, application Germany fan. 25, i961 Claims. (Si. -131) My invention relates to formwork for casting structural bodies, preferably from concrete, in which the form or shutter panels, on the side remote from the concrete, are provided with stiifening means such as ribs or the like, and with means for attachment of adjacent panels.

It has hitherto been customary to make wooden formwork from individual boards which are cut to shape and then nailed together. This is expensive and time consuming, particularly since such forms are subject to wear, for example due to weathering. To obviate these disadvantages, forms of sheet steel have been developed, in which plates of steel are connected together by detachable connecting means. Such steel formwork, however, is also expensive, and inconveniently heavy, and has the further disadvantage of air-tightly covering the moist concrete, so that the concrete has no chance to dry.

It is an object of my invention to provide formwork which combines the advantage of the known steel forms and the known wood forms without entailing the disadvantages of either and which, in particular, is provided with ribs like those of the steel plate formwork to impart great stability to the assembled form structure. Another object is to provide such reinforced formwork that can be assembled rapidly and accurately in a simple manner.

According to the invention, l compose the formwork, to be used for casting structural bodies, particularly of concrete, form individual panel units having ribs or the like reinforcing means and means for attachment of adjacent panel units arranged on the side remote from the concrete, and I provide each such panel unit with reference abutments which slightly project over the edges of the panel, these reference abutments being disposed at the corners of a rectangle or polygon in such a manner that a number of the panel units may easily be assembled in vertical and horizontal rows by means of such reference abutments.

According to another, preferred feature of the invention, the reference abutments are formed by longitudinal and transverse ribs which are fixed to the rear of each panel and constitute the above-mentioned reinforcing means, these reference abutments preferably having their abutment faces extend perpendicular to the plane of the panel.

According to a further feature of the invention, an accurate and firm connection between the individual panel units of the formwork is secured by giving the reference abutments of the individual panel units the form of connecting elements, such as pins and bores, which lie transversely to the ribs and parallel to each panel.

A jointless formwork is obtained, for example, from panels of laminated wood or plywood having xed transverse and longitudinal reinforcing ribs on the rear. Such panels, according to a further feature of my invention, are treated, at least on the surface adjacent to the concrete, with densifying substances such as phenol resins, urea resins, or by irnpregnating the surface with impregnated paper or the like, or by applying metal coating or by spraydepositing metals or synthetic resins. Such treatments impart great strength to the surface and make it resistant particularly to water.

Since the panel of laminated wood or plywood together with the reinforcing ribs of the rear surface form a single United States Patent O 'ice unit, the panel itself may be thin, thereby reducing the cost. The panel units can be given a particularly great strength by arranging the reinforcing ribs at equal distances from the edges of each panel, and accurately calculating the distances from the viewpoint of the static properties of the panel unit as a whole. The distance of each longitudinal rib from the respective adjacent edge of the panel is preferably 0.21 times the width of the panel. The transverse ribs have the same distance from the respective adjacent edges of the panel, so that there is a central area bordered on all sides by the longitudinal and 'transverse ribs and having 0.58 times the Width and 9.42 times the length of the panel. f

By arranging the longitudinal and transverse ribs in accordance with the invention, the panels are subjected to a minimum of bending stress because, with a uniform distribution of the stress over the Whole panel surface, the positive and negative bending moments will compensate each other. The transverse ties protect the panel against unforeseen stresses. Formwork constructed in accordance with the invention consists of jointless panel units which are easy to construct and inexpensive, and which can easily be assembled with adjacent panel units and have satisfactory strength and the necessary permeability to water.

An embodiment of form panels -according to the invention is illustrated, by way of example, on the accompanying drawings, in which:

FIG. l is a top plan View of a standard panel unit of water-resistant glued plywood, the position of the transverse bars being indicated by broken lines;

FlG. 2 is a section through the panel unit on the line ll-II of FIG. 1; y

FIGS. 3a and 3b are longitudinal sections through the panel unit on the line lll-III of FIG. 1;

FIG. 4 shows the ends of two adjacent ribs of two respective, adjacent panel units connected by means of U- shaped clamping stirrups, the illustration being a longitudinal section through the ends of the ribs;

FIG. 5 is a section perpendicular to the plane of two connected panel units, showing the adjacent ends of two ribs connected by means of a central wedge key;

FiG. 6 is a section parallel to the plane of the panel units to show the connection illustrated in FIG. 5; and

FIG. 7 is a partial top view of a formwork wall with one horizontal and two vertical rows of panel units, the figure serving particularly to indicate the arrangement of the reference abutments, the traverse bars being shown in broken lines and the connecting points by small circles.

The panel unit shown in FIG. l comprises a panel 2 to which are secured two parallel longitudinal ribs l and two transverse ribs 3. Overall, the panel unit is preferably 1250 mm. long and 625 mm. wide, measured between the two extreme ends of each longitudinal rib l. and each transverse rib 3 respectively. 'Ihe ends of the ribs l and 3 form respective reference abutments D, D', C, C', E, E', F, F' which project slightly over the edges of the panel 2. The measurements of the panel 2 itself are preferably 1248 mm. by 623 mm. The panel'Z is thus set back, all around, fromV the abutment faces, i.e. the protruding ends of the ribs, by an amount d, equal to about l mm. Due to this protrusion, only the confronting ends of the ribs come into contact when two adjacent panel units are joined together, a gap of about 2 millimeters remaining between the adjacent edges of the panels 2 so that the protruding parts of the

ribs

1, 3 provide abutting faces at their ends, for the relative location of adjacent panel units. Soiling of the edges of the panels 2 does not, therefore, affect the accuracy ofthe dimensions of the prefabricated panel units, whereas soiling or darnaging of the abutting yfaces of the ribs l, 3 is practically impossible, because these faces are tightly pressed against each other when the concrete is being applied. Instead of having .abutting faces which are perpendicular to the plane of the panel and formed by the end -faces of the

ribs

1 and 3, the reference -abutments D, C, E, vF may be obtained in some other manner. For example, they may be formed -by connecting elements such as pins and bores disposed transversely to the ribs and parallel to the panels.

By making the ratio between length and width of each panel unit 2:1, the units may be arranged in more than one direction, las shown for example in FIG. 7.

FIG. l shows, in detail, the ribs on the rear of the panel. The longitudinal or supporting ribs 1 are each arranged at a distance, lfrom their respective edges of the panel 2, equal to about 0.21 of the tot-a1 width B of the panel. Each of the transverse or stiening ribs 3 has the sarnev distance from its adjacent panel edge. Each of the eight rib ends has a U-shaped protective connecting cap 4, preferably of met-al, fixed to it to provide `the abut ting face. The abutting face of each cap is machined, and extends in a plane at right angles to the longitudinal axis of the respective rib. The abutting faces, which constitute the xed reference abutments D, D', C, C', E, E', F, F in accordance with the invention, 4and which, as mentioned, project over the edges of the panel by about l mm. are disposed on an accurate imaginary rectangle. The panel units can, therefore, be assembled with great precision to produce a formwork assembly which also is accurately rectangular. The invention therefore also affords the production of concrete structures of good surface appearance and is suitable at locations where it is exposed to view. Adjacent connecting caps 4 together form `a tension lock which can be pressed -together by locking means and can be easily separated for removing the panel units. v

According to a desirable feature of the invention, the distance of the

ribs

1, 3 from the respective edges of the panel is 0.21 times the width ofthe panel (FIG. l), which is particularly advantageous because the positive and negative moments acting on the panel unit (assuming the stress due to the soft concre-te is uniformly distributed over the `area of the panel) will be the same and will have the minimum value -for `a beam supported on two supports cantilevering at both ends. As a consequence of this, Very thin panels 2 may be used to take up very large stressees.

If one considers the bending properties of the panel unit, a distance of about 0.23 of the width of the panel between the rib and the edge would be preferable, but this would give the same results at the edge and in the central area of the panel 2. Also Aapplicable is a distance of 0.25 times the width of the panel between the ribs and the edges of the panel. This would not be in accordance with static optimal conditions, but would afford staggering the panel units in two vertically adjacent rows, which in some cases results in attractive appearance from an architectural point of view.

FIG. 2 `shows a cross section through the panel unit, the longitudinal ribs 1 being shown in section and the transverse rib 3 being shown in side elevation. It will be noted that the edges of the panel 2 are not quite ush with the connecting caps 4, but set back by the small amount d. The traverse bars 7 (FIGS. 2, 3) in this caseV are of the notched type. The notches accommodate steel tensioning rods S which act as connecting elements for two panel ends in the form assembly in the case of twosided wall formwork. Instead of a notched traverse bar, use may be made of slotted traverse bars in which the distances between the slots correspond, like the distances f between the notches, to the width of a standard panel, because in each case the tensioning rods must lie in notches 6 (FIG. l) 'provided in the edges of the panels 2.

FIG. 3 is a longitudinal section through the panel unit so that the transverse ribs 3 appear in section and a longitudinal rib 1 in elevation. Brackets 9 which hold the traverse Ibars 7 are attached by bolts 8. Each bracket 9 Ihas two hooks 8 which jointly straddle the longitudinal rib 1. A lug 8" at the bottom of each bracket 9 holds it at a right angle to the rib 1. An alternative embodiment shown in the top portion of FIG. 3 has a bracket 9' which has a direct tightening effec-t, and which is cantilevered by an amount equal to the width of the traverse bar 7. The bracket 9 shown in the lower portion of the figure is cantilevered outwards to a greater extent, and tightening is effected by means of a T-shaped key Sia which is permanently fixed to the bracket 9 and can be driven in parallel to the traverse bar 7. The tensioning rods S are shown at the -top and bottom in FIG. 3.

FIG. 4 is a section showing two adjacent rib ends held together by a wedging key which consists of a stirrup 1d pressing together with the two U-shaped connecting caps 4'. Each connecting cap i has a bore 11 to receive the key. Lateral displacement of the key, and hence mis- .alignment of the rib ends, is prevented by a round-headed screw 12in the center of one connecting cap and a corresponding recess 13 in the adjacent connecting cap (FIG. 4).

FIG. S is a section through a tightening lock which embodies a central wedge. Semicircular profiles i4 are welded or otherwise xed in-to the connecting caps 4. These proles `are enclosed by the iianks of a U-sectioned wedge key 15 which presses them together.

FG. '6 shows a section on the line IV-IV in FIG. 5 through the central wedge "15 in the same direction as the section in FIG. 4. It shows the position and functioning of the semicircular prole bodies 14 and the wedge 15 which is to be driven in from the side indicated by an arrow G. The forces exerted by the wedge 15 on the profile bodies 14 ,are indicated by arrows G1 and G2.

FIG. 7 shows a formwork wall with two vertical rows and one horizontal row of panel units. As illustrated, one horizontal panel unit may easily be connected with two vertical panel units, because the positions of the ribs are correlated to one another. This ligure also shows the eight point system of the connections between the panels, and the positions of the traverse bar '7, which is indicated in broken lines. The notches 6, indicated as small circles, receive the tensioning rods. A number of non-standard or compensating panel units are shown at the right-hand side for completion of the formwork to the desired dimensions. Two of these units have a width of Ms B, two have a width of Vs B and one has a length of 1%; L. These panels are indicated by the reference numerals 2a, 2b, 2c.

The edges and corners of the panels may be specially protected as indicated at 5 (FIG. l), for example by sheet members of metal or hard polyvinylchloride. This protective member may be in the form of a pocket, which secures complete protection. Each of the longitudinal panel edges, which may also be protected by proled coverings, is provided with two of the above-mentioned recesses in the form of

notches

6, 6 to receive the connecting rod of the two halves of an adjacent panel when the two panels are fitted together and the gap is closed. This rod is placed through the

notches

6, 6 and connects the panel with the traverse bar 7 on the rear side of the panel.

The positions of the

recesses

6,6 are so chosen that their distances from the adjacent edges of the panel are each 0.21 times the length of the panel. The traverse bar may be made of wood, metal or hard synthetic resin.

if desired, the reference abutments protruding over the panel edge may be located on connecting lines which form geometrical figures other than rectangles, for example right angles or isosceles triangles, parallelograms or the like. In certain cases, the ratio of the length to the width of the panel may be other than 2:1, for example 4:1.

It will be understood that the other numerical values givenabove are likewise intended as examples only. Thus, the longitudinal and

transverse ribs

1, 3 may be given a spacing from the edges of the panels dilering from 0.21

arenoso times the width of the panels. For example, a very rigid panel unit, resistant to bending, is obtained by placing the longitudinal and transverse ribs at a distance of 0.14 times the width of the panel away from the panel edges. In this case, an additional transverse rib may be provided in the middle of the iield formed by the mutually intersecting longitudinal and transverse ribs.

Such and other modifications of formwork panel units according to the invention will be obvious to those skilled in the art, upon a study of this disclosure, and it will therefore be apparent that the invention can be given embodiments other than particularly illustrated and dcribed herein, without departing from the essential features of my invention and Within the scope of the claims annexed hereto.

I claim:

1. A composite formwork for casting structural bodies from hardening material such as concrete, comprising a number of individual panel units, each having a front side to be contacted by the material to be cast and having a rear side, each of said panels having reinforcing means and means for connection to adjacent panels arranged on the rear side, and having a plurality of reference abutments rigidly secured to each of said panels and protruding slightly over each of the edges of the panel, said reference abutments having a thickness at least substantially equal to the thickness of said panels, being located at the rear side on the .corners of a regular geometric polygonal figure and having front sides respectively in ush abutment with corresponding front sides of abutments of adjacent panels, whereby a number of the panel units can be aligned and assembled in vertical and horizontal row by means of said reference abutments, said panels in assembled condition defining a relatively thin intervening gap between portions of adjacent panels, said abutments each protruding beyond the edges of the panels a distance half the width of said intervening gap, and clamping means for connecting abutments of adjacent panels to retain said panels in adjacent assembled condition.

2. In a panel unit according to claim 1, said reinforcing means comprising longitudinal and transverse ribs fixed at the rear surface ofthe panel, said abutments being the ends of respective ones of said ribs, said abutting faces being perpendicular to the panel surface.

3. In a panel unit according to claim 2, said longitudinal and transverse ribs being each spaced the same distance from the respective adjacent edges of the panel equal to about 0.21 of the Width of the panel.

4. A panel unit according to claim 2, comprising bolts which pass through said longitudinal ribs, brackets for receiving traverse bars, each of said brackets having two fork-shaped hooks jointly straddling one of said longitudinal ribs respectively and engaging said bolt when mounted for suspending -said bracket therefrom, and said bracket having a lug for xing the angular position of the bracket by engagement with 'said longitudinal rib.

5. ln a panel unit according to claim 2, the thickness of said panel in addition to the thickness of the longitudinal ribs being equal to the standard thickness of a panelling plank or twice the thickness of a panelling board.

6. In a panel unit according to claim 1, said reinforcing means comprising longitudinal and transverse ribs of nonmetallic material, said ribsl having respective ends provided with protective metal caps, said caps constituting said abutments and having respective abutment faces protruding beyond the adjacent respective edges of said panel and extending at right angles to the yaxes of the respective ribs.

7. A formwork of panel units according to claim 6, comprising a tightening lock consisting of U-shaped wedging stirrup, said caps of two adjacent ribs having respective bores engageable by said stirrup and the stirrup being centraily located relative to the caps being connected, whereby said caps and panel units are tightened together by driving the stirrup into said bores, said stirrup being positioned at least partially within respective ribs being connected thereby.

8. In formwork of panel units according to claim 7, comprising a central wedge key for fastening adjacent units to each other, said caps having semicircular proles, and said key being U-shaped and having its legs straddle said proles for pressing them towards each other, said key being positioned at least partially within respective ribs being connected thereby.

9. In a panel unit according to claim 1, said abutments having respective machined abutting faces extending a predetermined `distance over said panel edge with an accuracy within $0.2 millimeters.

Rater-ences Cited in the tile of this patent UNTED STATES PATENTS 76,672 Sutherland Apr, 14, 1868 146,207 Schneider Jan; 6, 1874 213,520 Mikkelson Mar. 25, 1879 953,383 Holman Mar. 29, 1910 1,540,570 Roberts June 2, 1925 1,652,480 Hutchins Dec. 13, 1927 1,707,336 Venard Apr. 2, 1929 2,017,553 Troiel Oct. 15, 1935 l2,236,616 Bosco Apr, 1, 1941 2,296,036 Horn Sept. 15, 1942 2,340,864 Carpenter Feb. 8, 1944 2,475,890 Hamilton July 12, 1949 2,506,485 Boudcusquire May 2, 1950 2,522,360 Hamilton Sept. 12, 1950 2,640,249 Symons June 2, 1953 2,698,536 Robertson Jan. 4, 1955 2,859,503 Hennig Nov. 1l, 1958 2,948,046 Immonetti Aug. 9, 1960 2,967,343 Williams Jan. 10, 1961

Claims

1. A COMPOSITE FORMWORK FOR CASTING STRUCTURAL BODIES FROM HARDENING MATERIAL SUCH AS CONCRETE, COMPRISING A NUMBER OF INDIVIDUAL PANEL UNITS, EACH HAVING A FRONT SIDE TO BE CONTACTED BY THE MATERIAL TO BE CAST AND HAVING A REAR SIDE, EACH OF SAID PANELS HAVING REINFORCING MEANS AND MEANS FOR CONNECTION TO ADJACENT PANELS ARRANGED ON THE REAR SIDE, AND HAVING A PLURALITY OF REFERENCE ABUTMENTS RIGIDLY SECURED TO EACH OF SAID PANELS AND PROTRUDING SLIGHTLY OVER EACH OF THE EDGES OF THE PANEL, SAID REFERENCE ABUTMENTS HAVING A THICKNESS AT LEAST SUBSTANTIALLY EQUAL TO THE THICKNESS OF SAID PANELS, BEING LOCATED AT THE REAR SIDE ON THE CORNERS OF A REGULAR GEOMETRIC POLYGONAL FIGURE AND HAVING FRONT SIDES RESPECTIVELY IN FLUSH ABUTMENT WITH CORRESPONDING FRONT SIDES OF ABUTMENTS OF ADJACENT PANELS, WHEREBY A NUMBER OF THE PANEL UNITS CAN BE ALIGNED AND ASSEMBLED IN VERTICAL AND HORIZONTAL ROW BY MEANS OF SAID REFERENCE ABUTMENTS, SAID PANELS IN ASSEMBLED CONDITION DEFINING A RELATIVELY THIN INTERVENING GAP BETWEEN PORTIONS OF ADJACENT PANELS, SAID ABUTMENTS EACH PROTRUDING BEYOND THE EDGES OF THE PANELS A DISTANCE HALF THE WIDTH OF SAID INTERVENING GAP, AND CLAMPING MEANS FOR CONNECTING ABUTMENTS OF ADJACENT PANELS TO RETAIN SAID PANELS IN ADJACENT ASSEMBLED CONDITION.