US2881501A - Concrete box-form construction - Google Patents

Description

V. G. RANEY CONCRETE BOX-FORM CONSTRUCTION Filed July 11, 1955 April 14, 1959 IN V EN TOR.

V/NCENT Gl. RAN/EY mmlww ATTORNEYS United States Patent O 2,881,501 CONCRETE BOX-FORM CONSTRUCTION Vincent G. Raney, Belmont, Calif. Application July 11, 1955, Serial No. 521,003 1 Claim. (Cl. 25-131.5)

This invention relates to the art of pouring concrete slabs, and more particularly relates to a concrete boxform structure designed to create voids in reinforced concrete slabs.

Heretofore it has been proposed to pour relatively large reinforced concrete slabs on the ground at the site of building erection. After the concrete has set, the slabs are elevated by hydraulic jacks or the like to provide a Prefabricated elevated floor structure for the building under erection. In the fabrication of such slabs it is desirable to create voids in the concrete to lighten the weight thereof and to reduce the amount of reinforcing steel required. ln this regard, conventional slotted corrugated paper or breboard cartons have been utilized as box-form units to create the desired number and pattern of voids in the concrete. More specifically, it has been conventional to place a plurality of such cartons in spaced longitudinal and transverse rows with the closed ends of the cartons facing up and the open ends down and with the iiaps of the open bottom ends extending laterally outwardly in ground engaging contact. According to usual practice, the laterally extending aps of adjacent boxes are taped together to maintain said boxform units in proper spaced relation, and reinforcing steel is then laid between the intersecting spaced rows of box-form units in generally rectangular criss-cross pattern. Wet concrete is poured over the mold form units and allowed to set and the slab thus formed is then elevated by hydraulic jacks or the like to its proper position as an elevated floor structure within the building as above noted. After elevation of the slab, the paper box-form units are removed leaving a series of voids in the underside of the slab arranged in what may conveniently be described as a wallie type pattern.

Ailthough reasonable success has been attained in pouring concrete slabs according to the above practices, the use of conventional slotted corrugated paper or fibreboard cartons as box-form units results in certain attendant disadvantages. For example, the laterally extending carton flaps used as spacers between adjacent box form units also form the pouring surfaces for the beam or girder defining portions of the finished slab. It is highly desirable that these portions of the completed slab be formed absolutely iiat and without depressions or cavities such as are created by the rectangular spaces or voids defined by the carton flaps at each corner or intersection of longitudinal and transverse rows of box-form units where the iiaps do not join or abut one another.

Another disadvantage in utilizing conventional slotted cartons with laterally extending bottom flaps in the above manner is that the wet concrete frequently seeps under the bottom corner edges of the carton units tending to iioat said units within the wet mixture. This, in turn, leads to imperfect formation of the slab, and can also render it diiiicult to subsequently remove the units from the voids which they form in the hardened COIICIC.

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The particular embodiment of the present invention which is illustrated in the drawings and which will be described hereinafter in more detail comprises a conventional half slotted carton made of corrugated paper or iibreboard material dening four sides, a closed upper end and an open bottom end and provided with a reinforcing partition snugly tted interiorly of the carton. The carton is positioned open end down on a rectangular sheet of corrugated paper or fibreboard material having a length and Width substantially exceeding the length and width of the open bottom carton positioned thereon. The laterally extending margins of the rectangular sheet define a continuous peripheral spacer ange extending laterally outwardly from the bottom edge of the carton. The inner portion of the rectangular sheet which the carton overlies is formed with a substantially X-shaped incisure or die-cut defining four substantially triangularshaped locking tabs which are bent perpendicularly upwardly from the plane of the ilat section into frictionally wedged engagement between the interior sides of the carton and the reinforcing partition iitted therein.

A principal object and advantage of the unit embodying the present invention is that the iiat section of material on which the carton rests defines a continuous and uninterrupted peripheral spacer ange extending completely around the bottom edges of each box forming unit. Unlike the spacer flaps utilized in the prior art devices of the character above mentioned, the rectangular ange of the present unit does not establish any voids or gaps at intersecting rows of box units. As a consequence, any desired number of the box units may be positioned in intersecting spaced longitudinal and transverse rows with the marginal edges of adjacent spacer ilanges of all units positioned in abutting edge-to-edge relationship. With adjacent spacer iianges of the units taped in edgeto-edge relation, there is established a completely smooth and iiat pouring surface which will not create cavities or depression in the beam or girder forming surfaces of the completed slab structure.

Another object and advantage of the unit constructed in accordance with the present invention is that the spacer iiange member provides a seal around the entire open bottom of each carton unit and prevents seepage of concrete under the edges of the carton with attendant disadvantages and difficulties encountered in the prior art structures.

A further feature of the present unit is that the spacer flange member in conjunction with the manner in which it is interlocked by upwardly extending tabs frictionally wedged between the reinforcing partition and the inner sides of the carton provides additional structural strength for the walls of the carton unit and thus renders the unit better able to withstand the vertical load and hydraulic pressure of wet concrete poured thereover.

Another feature of the invention is that the novel flange construction incorporated therein provides an easier and more positive way of accurately spacing the box-form units relative to one another in desired pattern.

Other numerous objects and advantages of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

Fig. 1 is a fragmentary perspective view of a plurality of box form units embodying the invention positioned and taped together in intersecting spaced longitudinal and transverse rows preparatory to pouring of concrete thereover.

Fig. 2 is a perspective view of a box form unit showing the major components in exploded relationship and showing other parts broken away in section.

Fig. 3 is a perspective view of the spacer flange component indicating the manner in which it is die cut and folded to from the locking tabs.

Fig. 4 is a perspective view of the box form unit of Fig. 2 shown in assembled condition and with portions broken away in section.

Fig. 5 is a fragmentary transverse sectional view of a concrete slab which has been poured utilizing the box form unit pattern of Fig. 1 `and with the box form umts still in form position.

Fig. 6 is a perspective view of a concrete slab viewed from below showing the box form units removed from the voids inthe concrete. Referring now more particularly to the drawings, a box form unit constructed in accordance with the invention may be considered as comprising three major components including an open-ended box structure A, a reinforcing partition B, and a spacer ange member C.

The box component A is shown as comprising a conventional half-slotted carton made of corrugated paper or iibreboard sheet material. More specifically, the carton is illustrated as defining four sides, indicated at 11, a closed top 12, and an open bottom 13. The closed top 12 may be formed by the usual overlapping aps 12a taped together at their adjoining outside edges as at 14. The reinforcing structure B may be considered as comprising a conventional slotted partition also made of corru'gated paper or breboard. Slotted partitions of the type indicated at B are well known in the paper box industry and, accordingly, the same does not per se cons'titute'part of the presenty invention. It will suiiice to remark that the partition comprises a first spaced parallel series of partitioning walls 16 which are slotted and interlocked with a second series of parallel slotted partitioning walls 17 extending at right angles to walls 16. The lcellular partition B is shaped and proportioned to be snugly fitted interiorly of the box structure A.

The spacer flange forming member, heretofore designated generally at C, is shown as comprising a rectangular section 18 of corrugated paper or berboard material having a length and width substantially greater than the length and width of the open bottom carton A. The rectangular section 18 is formed with an X-shaped incisure defined by die-cuts 19. It is observed that the diecuts extend diagonally of the rectangular section 18 and the terminal points 19a of said cuts are made to coincide 1n relative spacing and distance to the corners 20 of box structure A. Said die-cuts 19, in conjunction with fold llnes 21 joining the terminal points 19a together in rectangular pattern, define triangular-shaped locking tabs 22. As shown in Figs. 4 and 5, when the box unit has been assembled for use as shown in Figs. 4 and 5, the locking tabs 22 are folded and projected upwardly interiorly of the box structure A into snug frictional wedged engagement between the inner wall surfaces of sides 11 of the carton and the cellular slotted partition B.

In assembled condition it is observed that the margins of the section 18 extend laterally outwardly beyond the bottom edges of the box structure A to deline a continnous uninterrupted peripheral spacer flange 18a for the box form unit.

Fig. 1 illustrates how a plurality of box form units of the character above described may be positioned relative to one another to provide a unitary form construction preparatory to pouring a concrete slab. As illustrated, the box units A are arranged in intersecting spaced longitudinal and transverse rows with the spacer ange 18a of each unit in edge-to-edge abutment with spacer anges 18a lof adjacent units. As shown in Fig. 1, abutting edges of adjacent spacer flanges are taped securely together as indicated at 23. The arrangement of box form units in this fashion establishes a series of parallel longitudinal passages 24 which are diposed perpendicular to transverse extending passageways 26 intersecting passageways 24. Reinforcing steel rods 27 may be positionedm the passageways 24 and 26. The form construction 1ndicated in Fig. 1 may be completed by providing side and end form pieces (not shown) around the periphery of the box form units through utilization of conventional wooden form boards or the like.

It is noted that the abutting and taped flange portions 18a of the box units provide uninterrupted at smooth pouring form surfaces for the concrete beam or girder forming portions 28 of the slab shown in Figs. 5 and 6.

Moreover and as previously indicated, the upwardly projecting locking tabs 22 which are interlocked between the reinforcing partition B and the interior side walls of the carton unit A provide a seal round the bottom edge of the carton whichprevents seepage of the wet concrete into the interior of the form units. Additionally the interlocked ange component functions to reinforce and add rigidity and strength around the bottom edge of the carton unit.

After the concrete has been poured over the box form units, it is allowed to set whereupon the entire slab is elevated to its proper position within the building structure being erected. Thereafter the box form units are stripped from the slab leaving thedesired voids 29 in the completed slab structure.

Although the present invention has been describedl in some detail by way of illustration and example, itis understood that certain changes and modications may be practiced within the spirit of the invention as limited only by the scope of the claim appended hereto.

What is claimed is:

A concrete mold form comprising: a box-type unit madefrom corrugated paper material dening four sides, a closed top, and an open bottom; cellular reinforcing means mounted interiorly of said unit; an integral rectangular iat section of corrugated paper material having a length and width substantially exceeding the length and width of the open bottom box unit; means for mounting said unit on said at section with the margins of said at section extending laterally beyond the bottom edges of said unit deiining a continuous peripheral spacer flange, said means including an X-shaped incisure defining diagonally extending cuts formed through said at section; the terminal points of said cuts located and spaced relative to one another to coincide with the four corners of the open bottom box unit; four straight fold lines extending in rectangular pattern joining adjacent terminal points of said diagonally extending cuts and defining four triangular-shaped locking tabs; each locking tab bent upwardly along its fold line interiorly of said box unit in frictional wedged engagement between said cellular reinforcing means and an adjacent side of said unit.

References Cited in the flle of this patent UNITED STATES PATENTS 1,307,031 Allbright June 17, 1919 1,434,242 Allbright Oct. 3l, 1922 1,767,067 Goldsmith June 24, 1930 1,892,311 MacDonald Dec. 27, 1932 1,914,417 Goldsmith June 20, 1933 2,093,401 Carilli Sept. 21, 1937 2,775,019 Bemis Dec. 25, 1956

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