US 3148429 A
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Sept. 15, 1964 w. GARMON FORM FOR CASTING CONCRETE WALL SLAB Filed June 30, 1961 THELBERT W. GARMON W INVENTOR ATTORNEY United States Patent M 3,148,429 F011 FOR CASTING CGNCRETE WALL SLAB Thelhert W. Garmon, 4999 Hillside Drive, Fort Worth, Tex. Filed June 30, 1961, Ser. No. 122,388 1 Claim. (Cl. 25--1) This invention relates to building construction with particular reference to precast concrete slabs used in tiltup walls, and is an improvement over my prior Patent, No. 2,858,031, issued October 28, 1958.
One important object of my prior invention was to provide a means of handling precast concrete wall panels in a semicured or green condition in order to substantially reduce the waiting time between pouring the slabs and erecting same on previously placed foundation piers. The combined form and hoisting frame described therein was designed to eliminate damaging stresses on the partly cured wall slab during the process of raising the slab from the horizontal to the vertical position. To accomplish this, the flat surface on which the slab was poured, reinforced by heavy steel beams, was kept in contact with the slab until the slab was finally braced in a vertical position. Separable elements of the form were removed before hoisting to expose the lower corners of the slab to bear upon the foundation piers.
While this method of handling has been markedly successful, making it possible to use larger and heavier units than by previous methods, it has also posed the problem to the crane operator of lowering these heavy slabs onto the foundation piers gently enough to prevent damage to the exposed corners. The green concrete will carry its own weight, but there is limited margin for the increased force of impact. In order to speed up the work and reduce the danger of broken corners it is one object of the present invention to strengthen these corners by providing a built in steel bearing plate at the point of impact.
A further object of this invention is to simplify the forming process by which the corners of the slab are left exposed to be placed on the foundation piers.
A further object of this invention is to introduce a steel element bonded to the slab which can be welded to some other element of the building structure.
These and other advantages will become clearly apparent from the following description of which the accompanying drawing is a part, and in which:
FIGURE 1 is a perspective front view of the slab hanging in its combined erection frame and form.
FIGURE 2 is a perspective back view of the same.
FIGURE 3 is a broken elevational view of two slabs in place on the foundation piers and a third being lowered.
FIGURE 4 is a broken perspective view of a corner of the form before the slab is poured.
FIGURE 5 is a broken end elevational view of one corner of a slab.
As already described in my prior patent, the invention includes a steel frame comprising parallel longitudinal I beams 11 with appropriate cross bracing 12. The l beams are recessed as at 13 to make room for a rigid wooden concrete form base 14 which molds one face of the slab 15. The form base 14 has side pieces 16 and end pieces 17 temporarily attached to its surface to define the size and thickness of the slab 15. The outer face 13 of the slab is molded by the form base 14 and the inner face 19 is leveled off even with the upper edges of the side pieces 16 and the end pieces 17. A series of holes 20 are drilled in the side pieces 16 into which are inserted the ends of the horizontal reinforcing rods 21 3,148,429 Patented Sept. 15, 1964 which extend beyond the edges of the slabs to bond into columns, not shown, poured into forms to be built around the spaces 22 between the edges of the slabs 15' Vertical rods, not shown, are tied to the horizontal rods 21 in the usual manner before pouring the concrete.
Projecting feet 23 are welded to the I beams 11 at the lower end of the recess 13 and the lower end pieces 17 of the form are cut around these feet in such a way that the poured concrete bears against them and will rest upon them after the end pieces 17 have been removed and the form base 14 has been hoisted to a vertical position. Corresponding projections 24 are located at the upper end of the recess 13 but spaced somewhat away from the upper end of the slab 15. A hoisting yoke 25 is attached to these projections 24 which in turn is attached to a crane, not shown, by means of a hook 25a. Parallel stringers 26 are temporarily bolted to feet 23 and projections 24 to hold the slab 15 securely in place during the tilting operation. After diagonal braces, not shown, are attached to temporary brackets 27 to hold the slab in a vertical position on the foundation piers 28, the stringers 26 are removed and the frame 10 and the form base 14 fall away from the slab. The form base 14 has at each lower corner a rectangular notch 29 which is designed to leave the corresponding corner 30 of the slab 15 unencombered by the form base 14 where it is brought to rest on the pier 28.
This invention is directed specifically to a steel angle plate 31 which in order to contain the concrete over the notch 29 is dropped in place against the side pieces 16 and the end pieces 17 at the corner of the form as shown in FIGURE 4. One leg 32 of the angle plate 31 is the same length as the thickness of the slab 15 while the other leg 33 is of sufficient length to cover the notch 29. Anchor rods 34, welded to the leg 32, extend into the slab 15 far enough to bond the angle plate 31 securely to the concrete after the side pieces 16 and the end pieces 17 are removed.
In addition to closing the notch 29 in the form base 14 to contain the concrete during the pouring operation, the steel angle plates 31 provide a reinforced bearing for the corners 30 of the slab 15 to resist the impact of the slab on the piers 23 when the slab is lowered into place, and thus to prevent damage to the slab and consequent rejection.
In certain types of construction it is advantageous to be able to weld connections between the slabs 15 and other elements of the building. In FIGURES 3 and 5 optional steel plates 35 are shown resting on the top of piers 35 to which the angle plates 31 can be Welded. In smaller buildings where the sides are but two or three panels long and only eight or nine feet high (not illustrated) the projecting rod ends 21 can be eliminated and the space 22 between the slabs reduced to a fraction of an inch. Then the angle plates 31 on adjoining slabs can be welded to each other to provide a continuous wall structure while the space 22 is filled with caulking or covered with a metal strip. The top edges of the slab are tied together by a poured roof slab or a metal beam. Or if preferred, additional angle plates 31 can be included at the top corners of the slab for welding, it being unnecessary to modify the form to accomplish this.
The invention is not limited to the exemplary construction herein shown and described, but may be made in various ways within the scope of the appended claim.
What is claimed is:
A form for casting a concrete slab for a tilt-up wall comprising a flat base for forming one surface of said slab, and larger than the slab to be formed, side and end pieces removably attached to the upper surface of said base, notches at the corners of said base corresponding to the lower corners of the slab to be formed, said notches extending inside beyond the intersection of said side pieces and said end pieces, metal angle plates detachably fitted over said notches Within said side and end pieces, one leg'of each said angle plate covering the opening defined by the adjacent said notch and said side and end piece, While the other leg rests against said end piece, and said angle plates having integral projecting reinforcing bars adapted to extend into the slab.
References Cited in the file of this patent UNITED STATES PATENTS