US1445374A - Apparatus for constructing concrete floors - Google Patents

Description

Feb. 13, 1923.

. v I H. L. WELLS.

APPARATUS FOR CONSTRUCTING CONCRETE FLOORS.

2 SHEETS-SHEET l.

FILED AUG. 3| 1922.

Feb. 13, 1923 H. L. WELLS.

APPARATUS FOR CONSTRUCTING CONCRETE FLOORS.

men AUG-3. 1922.

2 SHEETSSHEET 2.

Patented Feb. l3, W23.

UNETED STATES PATENT (OFF-KGB.

HEWITT L. WELLS, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO WASH- INGTON STEEL FORM COMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA,-A COR- PORATION OF THE DISTRICT OF COLUMBIA.

APPARATUS FOR .CONSTRUCTING CONCRETE FLOORS.

Application filed August 3, 1922. Serial No. 579,516.

To all 10110111 52 may concern Be it known that I, Hnwrr'r L. hams, of \Vashington, in the District of Columbia, have invented certain new and useful Iniprovements in Apparatus for Constructing Concrete Floois; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the construction of reinforced concrete floors and walls and particularly to the method of erecting and removing the temporary forms.

In the construction of reinforced concrete buildings the cost of wood forms is one of the largest items of expense. This is due to the large quantity of lumber required, the high cost of labor in making up the form sections, and the time and labor of erection. In order that the concrete may attain sufficient carrying capacity it is necessary that it be temporarily supported by the forms and false work for a considerable time in its process of setting. For buildings having several supported floors it is, therefore, necessary to provide and build a set of forms for three or more floors in order that the work may progress rapidly. Extensive experience has shown that the salvage value of the lumber in wood forms is low even when the form sections are carefully designed, erected and removed. When stripped from the hardened concrete the pieces bind and are badly damaged, distorted and full of nails. The exposure of rebuilding for reuse is frequently as great an expense as would be to purchase new lumber. This is'particularly true of the wood sheathing which is laid over and nailed down to the temporary supports or false work beneath the concrete slab.

The object of my invention is to provide an "improved method of constructing the forms for the under side offloor slabs and for the sides of concrete walls and to effect a saving in the cost of materiad and simplify the labor of erection. This improved method of forming concrete slabs embraces the use of steel plates made of light gauge sheet metal cut and bent into the required form. These flat plates are laid between supporting false work of wood joists, downwardly bent sides of the plates forming flanges which rest upon a narrow wood strip prevlously nailed to the sides of the joists. the required distance below the top of the oists. So that the forms may be easily removed the downwardly bent flanges of the plate are at an acute angle, thus allowing the flange to stand away from the sides of the joists so as to not bind, the upper edge of such flanges. however, fitting tight against the upper side edge of the joist and at the same level. For the purpose of securing a satisfactory bearing along the narrow wood strips on the sides of the joists these downwardly bent flanges of the plates are bent inwardly. In order that the form plate will be sufficiently rigid, stiffeners .'made from wood are then fitted tightly between the edges across the width of the plates, thus binding the edges of the plates against the sides of the wood joists. If desired the stifi'eners may be of heavy gauge metal made in the form of channels and permanently secured in position on the plate or driven in place after the plates are laid, or the required rigidity and tightness may be had by using both means. When the concrete slab has sufficiently set to safely support a part of its dead weight the form plates may be removed. This is done by ripping off the side stripalong the wood joists, knocking out or releasing the stiffeners and allowing the plates to come down from below. The wood joists, therefore, continue to support the floor, their edges remaining in contact with the slab undisturbed. The entire form surface upon which the concrete is poured is at the same level. hen the joists have been previously dressed and made smooth and the entire floor area oiled the finished concrete ceiling will he found true and smooth which is most desired.

The steel form plates, therefore, displace the expensive wood sheathing and are so designed that their removal does not interfere with the joist supports, which are left in place until the concrete has attained suflicient strength when all the supporting false work may be removed. Since the form plates may usually be removed within three to four days after the concrete is poured one set -01: such plates can be quickly recovered for repeated use on other floors. This greatly lessens the cost.

Due to the wood stifi'ener fitted on the under side of the plates the steel sheets are sufficiently rigid to support the load over a span two to three times greater the distance between supporting joists than would be satisfactory for wood sheathing. The number of joists required with the plates are, therefore, less, eifecting considerable economy in the supporting false work.

In order that the standard length form plates can be made to cover any varying length of panel, the side flanges of all plates are partially cut away at one end, and to aid 1n quickly placing the plates in position and adjusting to required lap the exposed,

edges at the lap end are cut or tapered off.

In the drawings, Figure 1 is a top plan view of a portion of the slab centering showing my improved forms in position, the sides of said forms being broken away. Figure 2 is a sectional view on line 22, Figure 1. Figure 3 1s a view in perspective of one of the form plates. Figure 4: is a view, partly in section, showing the overlapping of the forms. Figure 5 is a sectional view on line 5-5, Figure 1.

In the construction of a concrete floor slab, I have illustrated one form of centering, and this includes posts or shores A with stringers B. Across the stringers at equal distances apart I place joists 1 to each of which, preferabl y at a point slightly below the top thereof, I nail wooden ledges 2, these being strips of wood of small cross section which support the metal forms 3. Each form is a flat metal plate bent downwardly at its sides at slightly less than a right angle, as at 4, and then inwardly as at 5, these downward bent sides forming flanges which rest upon the ledges 2, and also materially aiding in giving stiffness to the forms. Adjacent one end the sides of the forms are in part cut away, with their free edge tapered toward the end of the plate, as indicated at 6, so that in positioning a series the overlapping may be secured Without obstruction by the inwardly turned edges 5. To prevent sagging of the forms I provide braces 7. These braces are of a length slightly greater than the clear distance between the extreme sides of the forms to which they are a complement, and the ends of each are beveled. as at 8. The brace is placed at a slight angle to the ends of the form with its ends resting on the inturned edges of the form and is then driven tight to wedge its ends against the sides of the form. This causes a binding of the top side edge of the'form against the sides of the joists. As previously stated the flanges extend inwardly toward each other so that they will lie away from the sides of the joists so as to not bind when being removed.

lVhile I have described and shown a brace for the forms made of wood, which may be either fixed or temporary, it i' manifest that the forms may be braced by channel sections 10. In positioning the braces one is near one end and a second, at a point further removed from the other end so as to not interfere with overlapping of the ends.

The advantages of my invention will be apparent, it being noted that by the use of the metal form plate hereinbefore described in the manner set forth I am enabled to effeet a saving in lumber, the cost of labor of erection, and, consequently to lower-the cost of construction of this type of floor con struction.

I claim as my invention:

1. Means for forming a concrete floor, including a plurality of spaced apart supporting members, a series of metal plates spanning the space between said supporting members and having their upper faces approximately flush with the tops of said members, and means detachably secured to the sides of said members for maintaining said plates in position, and means for wedging said plates against said supporting members.

2..Means for forming a concrete floor, including in combination with a plurality of spaced apart supporting joists, and ledges nailed to said joists below the top thereof, a series of metal forms having each downwardly extending side flanges resting on said ledges, and having their upper faces in alinement with the top of said joists, and means wedged between the flanges of each form to strengthen it.

3. Means for forming a concrete floor, including in combination with a plurality of spaced apart supporting joists, and ledges nailed to said joists below the top thereof, a series of metal forms having each downwardly extending side flanges resting on said ledges and having their upper faces in alinement with the top of said joists, and a brace of length greater than the distance between the sides of said form wedged between the flanges of each form to strengthen it and bind the side edges of said forms against the sides of said joists.

4. Means for forming a concrete floor, including a plurality of spaced apart supporting members, a series of metal plates spanning the space between said supporting members having each downwardly extending side flanges tapered at one end, such tapered portion of one plate overlapping the next adjacent plate, the upper exposed face of each plate being approximately flush with the top of said supporting members, and means with which said flanges engage for maintaining said frames in position.

5. Means for forming a concrete floor, including a plurality of spaced apart supporting members, a series of metal plates spanning the space between said supporting members having each downwardly extend ing side flanges tapered at one end, such tapered portion of one plate overlapping the next adjacent plate, the upper exposed face of each plate being approximately flush with the top of said supporting members, means wedged between theflanges of each plate to strengthen it, and means with which said flanges engage for maintaining said frames in position.

6. Means for forming a concrete floor, including a plurality of spaced apart supporting members, a series of metal form plates spanning the space between said supporting members having each downwardly extending sides with their lower edges bent inwardly throughout a portion of their length and cut away throughout the remainder so as to overlap the next adjacent form, the upper exposed face of each form being approximately flush with the top of said supporting members, and means with which said sides engage for maintaining said forms in position.

7. Means for forming a concrete floor, including a plurality of spaced apart supporting members, a series of metal form plates spanning the space between said supporting members having each downwardly extending sides with their lower edges bent inwardly throughout a portion of their length and cut away throughout the remainder so as to overlap the next adjacent form, the upper exposed face of each form being approximately flush with the top of said supporting members, means wedged between the flanges of each plate to strengthen it, and means with which said sides engage for maintaining said forms in position.

In testimony whereof I have signed this specification.

HEWITT L. WELLS.

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