US176696A - Improvement in asphalt sidewalks - Google Patents

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UNITED vS'I'ATris vAfrmlvrfr ,Erren- SAMUEL R. SCHARF, OF WASHINGTON, DISTRICT OF COLUMBIA.

"IMPROVEMENT IN AsPHALTFslDEwALKs.

Specification forming part of Letters lfatent No. l 76,696, dated April 25, 1876; application. filed March 20, 1876.

To all whom it may concern:

Be it known that l, SAMUEL It. SCHARF, of Washington, inthe county of Washington and District oi' Columbia, have invented a new and useful Improvement in Asphalt Sidewalk; and I do hereby declare that the following is a full and 'exact description of the same, reference being had to the accompanying drawings, and to the letters of reference markedthereon. i The object of my invention is the production of a smoothand durable concrete asphalt sidewalk; and the novelty therein consists in the manner of making and laying the same, as more fully hereinafter described. l In order thatV those skilled in-the art may be enabled to make my sidewalk, I proceed to describe the same, having reference to the drawing, which represents a vertical section.

1n laying my sidewalk, the earth is excavated to a suitable depth and properly rolled, so as to be level and smooth, all soft places being dug out and lle'd in with lhard or suitable material.

Uporni this surface thus prepared I place a base, A, constructed as follows: Itake screened coarse gravel or broken stone, preferably the latter, in size from one-fourth of an inch to one inch in diameter, and heat the same in any convenient way. When the same is sufciently heated `to a point about' the bbilingpoint of coal-tar, from which abou/t four gallons of what is known as theheavy oil?" in forty gallons of coal-tar have been distilled, I mix with such coarse gravel or stones a sufficient quantity of 'such distilled coal-tar, (which has been previously heated,) while the same is boiling, to thoroughly coat said gravel orstones. y

The gravel or stone thus coated is placed hot upon the ground, prepared as described, 4to about the depth -or" one and one-half or two inches, and raked smoothly, and rolleduntil the same begins to grow stiff. A

Upon this base A, as described, I place av top course, B, prepared as follows: I take nely-crushed stone, preferably limestone, and

pass the same through a screen hav-ing onequarter-inch meshes, and heat the same in proper vessels. At the same time I take Trinidad or other natural asphalt, and melt the same in a suitable vessel until it boils. I then mix with the same about one-sixth part, in bulk, of heavy parafline-oil, and stir in the same thoroughly, keeping the mixture at a boiling heat. The heated fine stone is then stirred into the mixture above described, the heat being maintained under the same, until the composition becomes of a density which will `just run and assume a level when poured \upon the ground.

This composition is carried hot in suitable vessels and poured upon the base A to the depth of from one-half inch to an inch, and leveled off and smoothed with trowels, smoothing-boards, or other proper appliances. After the same is leveled the surface is dusted With lime, or fine sand, or pulverized soap-stone,

.or other fine material of similar nature, and

smoothed off .with smoothing-boards until. it begins to set or grow stiff.

` When this sidewalk is cold it is fit for use, and will be found to be very smooth and exceedingly durable.

I am aware' that'a paving composition was patented by A. B. Vandemark in 1871, wherein asphaltum and paraftine-.oil, heated together in the same vessel, have been intimately mixed with calcareous stone finely 'pulverized,.and rolled smoothly and solidly,

whereby an exceedingly smooth homogeneous pavement, resembling rock, has been produced.

I disclaim the invention described by said Vandemark, which differs from mine, inasmuch as he does not employ asphalt and paraffine-oil in the same proportions, nor mix them at the. vsame temperature, that I do. He uses line stone-dust, while I use crushed stone. He rolls vhis pavement to make it hard and smooth, while mine will not. permit rolling, and hardens by chemical action; and his pavement becomes very smooth and homogeneous. On the contrary, mine is neither homogeneous nor smooth, and therefore less .slippery and more sufe to `travel upon in wet or frosty weather.-

Having thus described my sidewalk, what I claim as new therein, and my in'vv'ention'7 is 1. -The sidewalk composed of the courses A and B, constructed and preparedv substantially :is described.

2. An upper course for a. sidewalk, comy posed of crushed stone, asphait, and paraffine mixed and prepared-:and laid substantially as described.

This specification signed and witnessed this 18th day' of March, l187 6.

SAM UELr R. SCHARF.

Witnesses M. M. ROHRER, CHARLES THURMAN.

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