US1752671A - Structural element - Google Patents

Description

April 1, 1930. H. M. KNIGHT STRUCTURAL ELEMENT Filed June 24, 1927 INVENTOR HERB E RT M KN IGHT- ill Patented Apr. 1, 1930 UNITED STATES STRUCTURAL ELEMENT Application filed June 24,

This invention relates to improvements in means for forming key-ways in pre-cast slabs and has particular reference to a metallic means for forming said key-ways.

One of the objects of the invention is to provide a thin metallic sheet so pressed, as that, when inserted in the mold or form into which the plastic material of the slab is to be poured, a key-way is automatically created by the presence of such metallic sheet. Another object of the invention is to provide a metallic key-way forming means, which at the same time acts as a surrounding and protecting means to the slab adjacent to said key-way. A third object of the invention is to pro 'ide such a key-Way forming means, which by suitable returns is tied into and immovably cast into the structure of the slab. A fourth object of the invention is to provide a key-way forming means which is united with a reinforcing means within the slab, the said forming means and the said reinforcing means acting together to strengthen the slab at and adjacent to the groove or key-way formed by the said means. Other objects of the invention will appear from the following description and from the accompanying drawings.

The accompanying drawings, Figures 1 to 6 inclusive, illustrate the usual and preferred embodiment of the invention but are not to be considered as inclusive of any and all forms in which the invention may be embodied, nor as exclusive of forms other than those indicated.

Referring to said accompanying drawings in which like numerals of reference indicate similar parts throughout the several views Figure l is an isometric view of a key-way forming metallic member, inserted in the mold or form for the slab, and before the pouring of said slab;

Figure 2 is a cross-section of a slab at the ke -way, after pouring, and while still within the slab forming mold, showing the metallic key-way forming member and the method of attachment to a reinforcing means;

Figure 3 is an elevation of an edge of the key-way forming member and indicates attachment thereof to a reinforcing member;

Figure i is a cross-section of a slab, at a 1927. Serial No. 201,075.

key-way, indicating a plain key-way forming member;

Figure 5 is a cross-section of a slab, at a key-way, indicating a corrugated key-way forming member; and

Figure 6 is a cross-section of a re-entrant groove or key-way bounded by rectilinear lines.

In the specific embodiment of the invention illustrated in said drawing, the reference numeral 1 indicates a pre-cast slab within mold or form 2. A metallic key-mold 3 serves to form a keyavay i. Lug extensions 5 are embedded in the mass of the slab, said lug extensions preferably having perforations (5 through which the concrete may tie together. Reinforcing members 7 are shown in the body of the slab and may be engaged by the curled ends 8 of said lug extensions if desired. Tack holes 9 provide for initially retaining the keymold in position in the form. Check-blocks 1.0 are inserted between said form and said key-mold to prevent mass material entering therein.

In forming a pre-cast slab in which a groove or key-way is an integral and important part, the creation of the void which constitutes the key-way is a diflicult operation. A core, of wood, or other material, is employed, which said core has to be subsequently removed in order that the designed void representing the groove or key-way may exist. The removal of this core is diflicult and expensive, and in cases where the groove is long sometimes becomes impossible to make a perfect removal of the said core.

This invention overcomes all of the objections inhering in the use of solid cores, by substituting a thin metallic sheet which is bent into the shape which it is desired that the groove shall have, and which is inserted into said mold in advance of the pouring of the slab material. When the material hardens it holds the key-mold firmly in the desired position and of the designed form.

Again, in slabs having grooves or key-ways therein, especially where the groove is of a reentrant type, the presence of such groove becomes an element of weakness in the slab. The reinforcing of this weaker element, and

- ards and difliculties by providing the uniting of the reinforcing elements of the slab with this weaker portion, where the keyway has been formed by the use of a solid core, is diflicult and often impossible. The removal of the solid core, when attempted in advance of the complete curing of the slab, is often attended with cracking or fracturing of the slab at or near the key-way.

This invention overcomes all of these haza key-Way forming meas which strengthens the slab at this, its otherwise, weakest portion, and at the same time provides an adequate means for uniting the key-way portion of the slab to the reinforcing elements of the slab, so that the entire slab acts as one to resist stress and disruption.

By creating iugs on the metallic plate which lugs are bent inwardly into the mass of the slab, the pia'te becomes held firmly within the slab mass. The ends of these lugs are coiled around the reinforcing members, to which they are, or may be, welded. By such welding together of the lugs and reinforcing frame the whole structure of keyforming mold and reinforcing members he comes a unit which may be inserted as one into the slab form in advance of the pouring of the slab. Such welding of these two elements still further augments the strength of the slab at or near the key-way portion.

By the use of a metallic key-way form, difficult or involved key-ways, such as corrugated, may be easily made, such as shown in Fig. 5.

The invention is susceptible to various shapes or configuration of key-ways as well as various constructions for tying the metal form permanently into the slab or structural element, and while I have shown several embodin'ients of the invention, it is to be understood that I do not restrict myself to any of these forms, as various modifications and changes maybe made in manufacture and use, and I do not limit myself except as set forth in the following claims when construed in the light of the prior art.

Having thus described my invention, I claim 1. In a pro-cast slab the combination of a plate as a lie; -way forming means, lugs on said means, a reinforcing element, and means engaging said lugs and said element.

2. In a pro-cast slab the combination of a plate as a key-way forming means, lugs on said means, a reinforcing element and means engaging said lugs and said element, and said lugs having perforations for entry of the material therein during casting of the slab binding the material on opposite sides of the lugs.

In a pro-cast slab, the combination of a plate forming a recntrant groove, said plate having end extensions directed inwardly and embedded in the material forming the slab, said extensions having perforations for entry of the material therein during casting of the slab binding the material on op posite sides of the extensions.

In a pro-cast slab having an end face and side faces at an angle to and intercepting said end face, the combination of a plate also roviding an end, face extending entirely across the end face of said slab and having side faces ci-ztending partly over the side faces of the slab said end face of the plate having a re-ei'itrant groove enabling the slab to be keyed through the end face to another similar slab.

5. In a pro-cast slab having an end face and side faces at an angle to and intercepting said end face, the con'lhination of a plate also providing an end face extending entirely across the end face of said slab and having side faces extending partly over the side faces of the slab said end face of the plate having a rc-entrant groove therein midway between the said side faces providing a symmetrical sfucture.

HERBERT M. HEIGHT.

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