US3495800A - Form and bracket for casting a stack of uniform concrete slabs - Google Patents

Description

0. J. FISHER 3,495,800 FORM AND'BRACKET FOR CASTING A STACK OF UNIFORM CONCRETE SLABS Feb. 17, 1970 Original Filed March, 16, 1966 INVENTOR. W49 J 1 76996? United States Patent 3,495,800 FORM AND BRACKET FOR CASTING A STACK 0F UNIFQRM CONCRETE SLABS Donald J. Fisher, 532 Homer St., Manhattan Beach, Calif. 90266 Substituted for abandoned application Ser. No. 534,742, Mar. 16, 1966. This application Apr. 17, 1969, Ser. No. 824,347

Int. Cl. E04g 11/28, 17/14; B28b 7/22 U.S. Cl. 249-20 3 Claims ABSTRACT 0F THE DISCLOSURE The present invention relates to a device to facilitate building construction procedures, particularly those employing the application of precast concrete, tilt-up wall construction and lift slabs. The present invention also relates to an improved method for the casting of a plurality of concrete slabs employing the devices of the present invention. Specifically, the present invention relates to a new bracket for retaining the concrete forms in which the slabs are cast.

The method of constructing buildings by the use of precast concrete slabs is well known in the art and has become increasingly popular as a quick and inexpensive method of construction. It is the practice to cast such concrete slabs at the building site rather than attempting to transport them from another location. These concrete slabs are used to form either the floors or the walls of a building. Where the floors of a multiple story building are to be precast, it is frequently the practice to install vertical bearing members and then to cast all of the slabs at ground level in layers, one on top of another, separated by suitable means for preventing their adherence to each other. Employing suitable jacks secured to the vertical bearing members, the slabs are thereafter raised to their desired positions.

Where precast slabs are to be used as walls, it is frequently the practice to cast them as large panels of sufficient length to establish the desired height of the finished building, whereupon the slabs are tilted upward and installed in place using a suitable crane. It is not uncommon that such tilt-up wall panels will be used to form a building of several stories in height. A great savings in cost and ease of construction can be obtained by casting the majority of such panels for a particular building of the same outer dimensions, inserting suitable forms in some of said panels for windows, doors or other apertures. Thus, all of the panels having the same outer dimensions are cast in a stack, one on top of the other.

For each of the aboveanentioned types of construction, it is extremely desirable to maintain the dimensions of each of the slabs within acceptable tolerances as they are cast one on top of the other. To do this, a number of carpenters are employed to construct the first forms directly on the ground to the desired dimensions. When the carpenters have completed their job, the concrete is poured into the form and finished as desired and permitted to set. A chemical substance or a layer of material is then applied to the upper surface of the first slab to prevent the second slab from adhering to it when it is poured. The carpenters are then called in to construct the second form directly over the first one, duplicating the dimensions as well as possible. When this is done, the second slab is poured and permitted to set as before. Each of the additional slabs is prepared in the same manner. For tilt-up walls as well as for flooring, these slabs are ordinarily about six inches in thickness, and it will be obvious that the stack of precast slabs will quickly rise to a considerable height. Where the slabs are of considerable dimension, lateral support of the forms will obviously be required in order that all the sides of the slabs will be straight and true. This is not particularly a problem where the slabs close to the ground are being cast, but becomes an ever increasingly complex problem as the height of the stack grows. It is presently the practice to provide this lateral support by means of inclined supporting members forced against the sides of the forms and extending downwardly to the ground where their ends are secured against movement. As the stack of slabs grows, more and more of such supports are needed of ever increasing length, and working around the construction site becomes increasingly hazardous and cumbersome.

The lumber employed for such forms is essentially unusable for any other purposes after having been used in connection with the concrete since it ordinarily undergoes severe mishandling when it is removed from the hardened slabs and furthermore, the concrete in contact with the lumber severely dried it out. Accordingly, although a low grade of lumber is selected for this purpose, it represents a substantial cost which is not recoverable.

Briefly described, the present invention obviates a great number of the difiiculties mentioned above and results in a saving of both materials and labor by using only one form for all of the casting operations. This eliminates the cost of a large quantity of lumber and further eliminates the time and expense of carpenters to construct each of the forms for each of the successive slabs. By utilizing the unique brackets disclosed by the present invention, the form is securely mounted upon the first precast slab and supported in such a manner that the dimensions are precisely duplicated. By constructing a form using lumber of slightly higher grade than now customary, the form can withstand the casting of a large number of slabs before it is rendered unusable by the deteriorating effects of the concrete. The form-s can be easily attached and removed by the masonry workers thereby eliminating the need for specialized carpentry skills.

It is an object therefore of the present invention to provide a bracket which can be used in conjunction with appropriate forms to facilitate the construction of concrete slabs in multiple layers.

More specifically, it is an object of the present invention to provide a new bracket which securely retains the forms in position to permit the pouring of each successive slab of concrete in a multiple layer operation.

It is a further object of the present invention to provide a construction bracket substantially eliminating excessive quantities of lumber presently used in the construction of multiple layers of slabs.

It is another specific object of the present invention to provide a construction bracket which eliminates the necessity for specialized skills in carpentry during the construction of multiple layers of concrete slabs.

It is another object of the present invention to provide an improved method for the construction of concrete slabs.

More specifically, it is an object of this invention to provide an improved method of constructing concrete slabs in multiple layers by employing a single form in conjunction With a number of brackets.

Further objects and advantages of the present invention will become apparent upon reading the ensuing description in conjunction with the attached drawings in which:

FIGURE 1 is a partial perspective view illustrating the use of the brackets of the present invention in constructing concrete slabs in multiple layers.

FIGURE 2 is an enlarged, partial, sectional perspective further showing the employment of the bracket of the present invention and the method of construction.

FIGURE 3 is a sectional side elevation taken along line 3-3 of FIGURE 2.

FIGURE 4 is a perspective view of a preferred embodiment of the bracket.

FIGURE 5 is a perspective view of another form of the bracket.

FIGURE 6 is a partial elevation of another form of bracket shown mounted in a form.

FIGURE 7 is a sectional side elevation taken along line 7-7 of FIGURE 6, further illustrating the details of the form of bracket shown therein.

Turning now to the details of the drawings, a first slab of concrete is indicated 10 and the second slab is indicated by the numeral 11. The steps taken to construct the first slab 10 are not shown in the drawings since such steps are those customarily employed with but a few exceptions. The forms 12 are first cut and fitted to the exact inner dimensions required for the slabs and are mounted upon the ground in a usual manner to form a large flat slab 10. Apertures may be provided in the forms 12 to permit the insertion therethrough of a plurality of reinforcing bars 13, if it is desired that the ends of the reinforcing bars extend past the outer edges of the slabs. The exception to these usual construction steps is the provision of additional apertures in the forms 12 and the positioning of bolts or threaded sleeves 0n the inner side of the forms 12 so that the concrete poured to form slab '10 will securely embed such sleeves or bolts in the concrete itself. For example, FIGURE 3 shows a threaded sleeve 14 embedded in the edge of first slab 10 adapted to receive a cap screw 15 therein during subsequent casting operations. During the casting of slab 10, however, the sleeve 14 may be held in place by any suitable means, such as a shorter cap screw. FIGURE 7 shows the alternative use of anchor bolts 16 initially embedded in slab 10. It will be obvious to persons skilled in the art that there are a number of alternative devices which could be employed to provide either a male or female threaded connection means. It is likewise contemplated that suitable threadable means could be employed utilizing the presence of the reinforcing bars 13.

After the slab 10 has been poured, and finished plumb and square, the forms 12 are removed. The brackets 17 are then secured to the threaded means anchored in the slab 10 such as the sleeve 14 or the anchor bolts 16 as shown in FIGURES 3 and 7. Bracket 17, best shown in FIGURE 4, consists of a generally U-shaped channel member including a web portion 18, a concrete-abutting flange 19 and a rear flange 20. The abutting flange 19 extends only partially the length of bracket 17 and is cut olf to form a shoulder 21 extending into the web 18 a desired distance, whereupon the exposed edge of web 18 provides a form-abutting portion 22. The depth of shoulder 21 from the outer surface of abutting flange 19 to the surface of portion 22 will be determined by the thickness of the forms 12. Customarily, the forms used in similar operations are three-quarter inch or one and one-half inch lumber, the thicknesses of which are standard. The abutting flange 19 is provided with a longitudinal slot 23 and immediately opposite it, is a second longitudinal slot 24 in the rear flange 20. Near the upper end of bracket 17 there is provided a third longitudinal slot 25 in rear flange 20.

The bracket 17 is secured in place to the lower slab 10 by the cap screw 15 which extends through slots 23 and 24 and is threaded directly into the sleeve 14. Before the screw 15 is tightened, the shoulder 21 is aligned as closely as possible with the upper surface of slab 10 as shown in FIGURE 3. The cap screws 15 are then tightened. When all of the desired brackets are secured in place in this manner, the forms 12 are moved into place resting upon the shoulders 21 of each of the brackets 17. A second cap screw 26 is then extended through the slot 25, through the form 12 and threaded into additional threaded sleeves 14a and tightened to force the forms 12 into secure abutment with the portions 22 of the bracket 17. By this procedure, the forms are aligned perfectly with the outer edges of the first slab 10 so that the second' slab may be poured directly over the first slab, resulting in slabs of uniform dimensions. A sheet of material or a suitable chemical substance may be placed over the surface of slab 10 prior to the pouring of the concrete to cast slab 11 so that they do not adhere to one another. When slab 11 has been poured and finished so that its surface is true, the lower cap screws 15 are detached from the lower slab 10, the upper screws 26 are detached from the sleeves 14a and the form 12 and the bracket 17 are moved upward and the cap screws 15 inserted into the sleeves 14a of slab 11 above. The screws 26 are then attached to a new set of sleeves in a similar manner. Each successive slab is then formed in the same manner, the longitudinal slots 23, 24 and 25 permit adjustment for the correct thickness of the next slab and give greater flexibility for mounting the bracket. It should be noted that the overall length of the brackets 17, particularly the length of the abutting surface 22 above the shoulder 21, should preferably not be such as would extend the end thereof above the top edge of the forms 12, as this may hinder scraping and finishing operations. The number and location of the brackets shown in FIGURE 1 is not intended to limit in any way the number and location of brackets to be used in accordance with this invention. Normally, panels having an approximate dimension of ten feet by twelve feet are constructed and it is found that suificient support is obtained by using brackets every four feet and at each corner. This of course may vary depending upon the thickness of the forms 12 and the thickness of the slab themselves.

FIGURE 5 illustrates another form of bracket which may be used and which is of simpler construction. This bracket, designated by the numeral 51, consists of an essentially flat piece of stock which is bent to form the shoulder 52 of sufiicient width to receive a form 12. The lower half 53 of the bracket is provided with a longi tudinal slot 54 and is the portion which abuts the lower, precast slab. The slot 54 provides for the insertion of a bolt or screw to secure the bracket in place. The upper half 55 of bracket 51 has a slot 56 so that the form 12 can be secured thereto, similar to the manner described with respect to the bracket shown in FIGURE 3. The form of bracket shown in FIGURES 6 and 7 differs from those described heretofore in that this bracket employs additional reinforcing members abutting the forms themselves. The bracket 61 consists of an enlarged body portion 62 which is provided with a plurality of lateral flanges. The lower-most flange 63 is provided with a longitudinal slot 64 and is adapted to abut the outer edge of the lower slab 10 as shown in FIGURE 7. The slot 64 receives the threaded end of the anchor bolt 16 and the nut 65 secures bracket 61 in position against precast slab 10. A shoulder 66 is provided as in the other brackets, and is adapted to receive thereon the edge of the forms 12. Thus, the depth of shoulder 66 is provided to accommodate the thickness of the forms 12 as accurately as possible. The body 62 is further provided with a pair of substantially rectangular cutouts 67 and 68 having dimensions suflicient to receive standard two-by-fours therein. As shown in the drawings, these twoby-fours 69 and 70 are adapted to extend laterally along the length of the forms 12 to add to the lateral rigidity of the overall form itself. It is not necessary to have the forms 12 connnected directly to the two-by-fours '69 and 70 but it may be preferable to have the bracket 61 secured to said two-by-fours. In any event, flanges 71 and 72 are formed from the body 62 of bracket 61 and may have the apertures 73 shown so that the bracket can be secured to the two-by-fours as by the nails 74 shown or other suitable means. Prior to pouring the second, and subsequent slabs, the second anchor bolt 16a will be inserted in an aperture through form 12 to provide means for anchoring the bracket 62 for the next subsequent casting operation.

The modified form of bracket shown in FIGURE 6 and 7 will be particularly advantageous where the thickness of the slabs 10 and 11 is such that more lateral support is required than the other types of brackets are able to provide. In addition, the lateral supports provided by the two-by-fours 69 and 70 will permit the placement of brackets 61 at greater intervals along the length of the slab so that a lesser number of such brackets need be employed in a given operation, thereby decreasing the number of attachments and removals which must be made to move the form upward for each successive casting step.

It will be seen at once, that the present invention provides an improved method of constructing the forms thereby significantly decreasing the difficulty of such construction techniques and substantially lowering the costs thereof. The brackets shown in this invention can be easily and inexpensively manufactured and will provide a long service life before replacement will be necessary. While several embodiments of the bracket have been shown and described, it will be obvious to persons skilled in the art that other similar configurations of brackets could be formed in accordance with the teachings of this invention. Changes and modifications of these brackets and of the steps of construction outlined herein will be obvious and it is the aim of the appended claims to cover all such changes and modifications as fall within the true scope and spirit of this invention.

I claim:

1. A construction device for the casting of uniformly sized concrete slabs in multiple layers, the combination comprising:

a form;

a bracket, said bracket comprising a first portion adapted to abut the edge of a first precast slab, means atfixing said first portion to said first slab, said first portion including a flange, said flange having an aperture adapted to receive said aflixing means therein;

a second portion of said bracket having an edge adapted to abut said form, said second portion including one or more cutouts adapted to receive lateral reinforcing means in abutting relationship to said form; a shoulder situated intermediate said first and second portions, said shoulder adapted to receive said form thereon, whereby the inner surface of said form is aligned with the abutting surface of said first portion;

said afiixing means operative to position said shoulder in alignment with the upper surface of said first precast slab. 2. A bracket of the type described in claim 1 wherein said second portion further includes a flange adjacent each of said cutouts and means for securing said flange to said lateral reinforcing means.

3. A construction device for the casting of uniformly sized concrete slabs in multiple layers, the combination comprising: a form; a bracket, said bracket comprising a U-shaped channel member having first and second flanges separated by a web portion;

said first flange extending a portion of the length of said bracket, a shoulder formed at the end of said flange situated near the approximate center of the greatest dimension of said bracket, said shoulder extending into said web portion, an abutting edge formed along the length of said web above said shoulder, said first flange having an aperture therein adapted to permit the attachment thereof to a precast slab and operative to position said shoulder in alignment with the upper surface of said precast slab;

said second flange extending the entire length of said bracket along its greatest dimension, at least one aperture in said flange situated intermediate the length of the abutting edge of said web, said aperture adapted to receive affixing means for securing said form to said bracket;

said shoulder having a dimension corresponding to the thickness of said form.

References Cited UNITED STATES PATENTS 2,649,643 8/ 1953 Schutte 24910 FOREIGN PATENTS 1,070,258 2/ 1954 France.

1,136,839 1/1957 France.

I) ROBERT D. BALDWIN, Primary Examiner US. Cl. X.R. 25131; 249219

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