US516113A - Concrete construction - Google Patents

Description

(No Model.)

E. L. RANSOME. CONCRETE CONSTRUCTION.

f To all whom it may concern:

UITED STATES PATENT irren,

ERNEST LESLIE RANSOME, OF OAKLAND, CALIFORNIA.

CONCRETE CONSTRUCT! ON.

SPECIFICATION forming part of Letters atent No. 516,113, dated March 6, 1894. Application tiled November 6, 1893. Serial No. 490,185, (No model.)

Fe it known that I, ERNEST Lustre RAN- SOME, a citizen of the United States, residing at Oakland, in the county of Alameda and State of California, have invented an Imprcvement in Concrete Constructions; and I hereby declare the following to be a full, clear,

and exact description thereof.

4My invention relates to that class ot structnres of concrete, brickwork, or like material,

j in which the tensile strength of the construction is increased by the embedxnent and intreduction of iron bars into the body ot the i. 5o square, onetenth twist to material, and is an improvement upon the construction for which Letters Patent No. 305,226, of September 16,1S8l,were granted me. By that invention I created a continuons bond between the iron and concrete, by using polygonal bars of iron so twisted as to form long spiral threads on the bars.

My present invention consists in using similar bars of iron in like manner, that have been twisted cold, that is to say using bars ot iron which were twisted while the iron was in its normal condition,cold, instead ot being heated for the operation, for I have disoovered that structures in which cold-twisted hars are used are much more rigid and also stronger and capable of sustaining greater loads than when such bars are used hottwisted, or untwisted, and this quality ot coldtwisted iron applies with equal force to iron of any cross section, whether it be rounder square. The amount of twist to be given to the bar may vary considerably. The more they are twisted, the stronger and more rigid is the structure in which they are used, provided the cold-twisting is not carried too near to the point of rupture.

In practice I usually give as follows: bars one-fourth inch diameter, or square, six twists to the lineal foot; bars one-half inch diameter, or square, three twists to the lineal foot; bars three-fourths inch diameter, or square, two twists to the lineal toot; bars one inch dialneter,*fory square, three-fourths twist to the linealitoot; bars one and one-half inches diameter, or square, Onehalf twist to the lineal `^oot5`bars two inches diameter, or the lineal toot.

This twisting can be readily done in any ordinary iron lathe of suhicient strength, by rigidly fastening one end of the bar to the headstock or face plate ot the lathe, and fastening the other end of the bar to the tailstock (both stocks being held also rigidly in their relative positions), and turning the lathe and bar inthe ordinary manner ot lathe turning.

The accompanying drawing illustrates the position of these bars in a slab of concrete.

ct, a, are supporting walls, h, a concrete slab, c, a cold twisted bar embedded in the concrete for the purpose of increasing its tensile strength.

For the purpose of this invention,I regard stone work, brick work, glass, or other structural substances of less elasticity than the bars of untwistcd iron, such as cast iron, as the equivalent of concrete. And other metals that may be in like manner affected by coldtwisting as the equivalent of iron.

In many constructions this lessenin g of the ductility and elasticity of the iron would be of a greater disadvantage than the corresponding gain in strength due to the coldtwisting. But in concrete structures the lessening of the ductility of the iron of itself is a great and positive benefit, and meetsua want long sought after, viz: that of causing the iron and the concrete in which it istan-- bedded to work harmoniously and in unison together when subjected to strain. The nearer the elasticity of the iron approaches that of the concrete without sacriiieing its strength, the better; because the more they are separated from one another in degree the more certain is the concrete structure to crack and break when under strain.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is

A structure of concrete or similar naterial having cold-twisted metal bars embedded in said material for strengthening the saine.

ERNEST LESLIE RANSOME.

Witnesses:

H. F. THOMSEN, MINNIE Pn'rnason.

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