US1444431A - Concrete stair construction - Google Patents

Description

Feb" 6, 1928. 1,444,431. F. A. SEIFERT.

CONCRETE STAIR CONSTRUCTION.

FILED FEB. 2, 1920.

6 FEgDZD ENVENTUH FASEIFERT ATTORNEY Patented lFeb. 6, 1923.

a STATES LMQ AQIL FRANK A. SEIFERT, OF ST. LOUIS, MISSOURI.

CONCRETE STAIR CONSTRUCTION.

Application filed February 2, 1920. Serial No. 355,746.

useful Concrete Stair Construction, of which the following is such a full, clear, and exact description as will enable any one skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

My invention relates toa concrete stair' construction and has for one of its objects the production of a monolithic stair step comprising a tread and riser so reinforced as to prevent cracking of the step by the unequal expansion and contraction of the reinforcing metal and the material of the step. Another object of my invention is to provide the step with an integral non-slipping surface covering a portion of the tread and preferably also the nose of the step. Still another object of my invention is to provide improved means for securing the various steps ,of the stairs together.

In the accompanying drawings which illustrate one form of stair construction made in accordance with my invention, Figure 1 is a vertical cross section, and Figure 2 is a section taken on the line 22 of Figure 1.

My step consists of a tread. 5-and a riser 6 composed of concrete and formed in a,

single piece. The step is held together by a uniform binder such for instance as Portland cement. The filler of the body both of the tread and riser consists of crushed stone or marble or similar material and a non-slipping tread 7 is provided which extends over a portion of the upper face of the tread and the filler of which consists of carborundum or other abrasive material. This non-slipping portion 7 preferably also extends down over the nose 8 of the step. The portion of the tread lying at the rear of the abrasive surface 7 may consist either of plain or ornamentalconcrete; in either case, it is non-abrasive in comparison with the carborundum surface 7. In order to strengthen the step at the corner, I increase the thickness of the earborundum filler at 8*,

preferably forming the inner limit of the carborundum on a curve to obviate an angle at the junction of the two kinds of filler.

9 is a reinforcing strip of perforated material which is placed in the interior of the step extending through both the tread and the riser and supplied at intervals with longitudinally extending bends 10 so as to prevent cracking of the material of the step by the unequal expansion and contrae- 1 tion of the materials. I" find in practice that if these bands 10 are arranged at a distance of about four inches apart the desired result will be accomplished.

The inner end of the step is supported by suitable means such, for instance, as an an le iron 11, and the lower face of the trea 5 is provided adjacent to the nose 8 with a groove or slot 12 adapted to receive the edge of the riser of the next lower step. The stair may consist of any number of these steps, as desired, and the upper and lower ends of the step are finished by portions, one consisting of a tread only and the other of a riser only, which tread and riser abut against the upper and lower floors 13 and 14 respectively.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. As a new article of manufacture, a monolithic concrete stair step comprising a tread, said tread having a facing of abrasive material extending over the forward portion of the tread and downwardly oven the front edge thereof, the thickness of said abrasive material being increased at the front corner, and a non-abrasive portion of tread extending to the rear of said portion of abrasive material.

2. As a new article of manufacture, a

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