US117286A - Improvement in pavements - Google Patents

Description

117285 MNTED JUL251871 N EWM@ Un-iran Sira'rns ISAAC H. HOBBS, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN PAVEMENTS.

Specification forming part of Letters Patent No. 117,286, dated July 525, 1871.

To all @cham 'it may concern:

Be it known that I, ISAAC H. Horns, of the city and county of Philadelphia and State of Pennsylvania, have invented certa-in new and useful Improvements in Pavements for Streets; and I hereby declare the following` to be a full, clear, and exact description thereof, reference being had to the accompanying drawing and to the letters of reference marked thereon.

The object of my invention is to furnish7 at a moderate cost, a pavement constructed upon such principles and resting upon such a foundationas shall secure absolute firmness and solidity of structure, evenness of wear, and consequent freedom from ruts, indentations, and inequalities of surface, increased durability, and facility of removal and repair for necessary excavations in and under the street, and for the introduction of horse-railroads without disturbing the substrata, as there is sufficient space above the stone, slag, or cobble foundation and the concrete illing thereupon to admit of the stringers and other ties necessary to their construction being laid directly thereon.

One of the principal difficulties heretofore attending the use of wooden pavements7 when constructed in any of the ordinary methods, has been the tendency to form depressions and inequalities upon the surface consequent upon the rotting or giving way of the foundation upon which such pavements rest. To obviate this, and to produce a pavement which shall meet all possible exigencies of weather, climate, and wear, as well as to afford relief' from the annoyance of frequent repairs originating in the imperfect methods of construction generally employed, after the street has been properly graded I construct a foundation of broken rock, Cobble-stone,

or slag, and upon this, either with or without the intervention of cement or concrete, arrange the wooden pavement embodying the improvements herein described, thus uniting the durability of the former with the smoothness, elasticity, noiselessness, and cleanliness of the latter.

Figure l represents a plan of a pavement embodying my invention. Fig. 2 is a vertical longitudinal section of he same .as shown at A in Fig. l. Fig. 3 represeg-side and end view of blocks of the shape comme ly used. Fig. 4 is an end view of the concrete mldings as shown at D in Fig. l. i

In constructing the foundation for the pavement, after the street has been properly graded, I prepare a layer of gravel or coarse sand, F, eX- tending over the entire surface ofthe street, be-

tween the ciu'bstones E E, as shown in Fig. l.

Upon and in this is arranged and rnily embedded the broken rock, cobble, or slag foundation, as at I I. This foundation is then pounded or rammed down with ordinary rammers constructed for that purpose, until it presents a perfectly regular surface ofthe required arch or curv ature for the street. Upon this is placed. a layer of cement, H, from one and a half to three inches in thickness, or of concrete composed of coalashes, pebbles, or broken stone, to which is added a suflicient quantity of mineral or vegetable tar to give it the requisite consistency and to unite the whole into one mass. It is then firmly rammed down upon and into the interstices below, and smoothly rolled over, preserving' at the same time the proper conveXity of surface for the street.

It is not absolutely necessary for the purposes of my invention that this layer of cement or concrete should be placed upon the rock or slag foundation and intervene between it and the wooden blocks above, although I greatly prefer it. But a good and very durable pavement may be made by laying the block directly upon such foundation without the intervention of the concrete or cement.

Upon the foundation constructed as above described I lay the wooden pavement composed' of blocks of the requisite length, thickness, and shape, and which, for the greater durability of the same, are kyanized. ln the pavement as shown at A in Fig. l the sides of the blocks are either parallel or chamfered, sloped or beveled oft' on one or both sides, from about the middle of the same to the upper end of each block, until the thickness at the top is reduced about one inch less than at the bottom, as shown in Fig.2. A concrete, composed of gravel, broken stone, coal-ashes, sand, and tar, or other like material, in any of the known and most approved methods and proportions, is then made and compressed into suitable molds of about a yard or any convenient length for the purpose required, and the moldings then taken out and either wholly or partially dried. lhese are of the same height as the blocks, and of the requisite thickness to effect a separation of the rows thereof from each other to the extent desired, and of a shape corresponding thereto. When the blocks are beveled off at the top the moldings are made correspondingly wider at that end, and form from the middle of the same, or thereabout, upward, a wedge or semi-wedge shape, as shown at D in Figs. l and 2, and also in Fig. 4. And when the sides of the blocks are parallel the sides of the moldings are parallel also, the object of which correspondence in shape is that they may it closely between the rows of blocks. The blocks are then arranged endwise in rows across the street, with the grain of the wood set vertically thereon, and interposed between each row thereof are these concrete moldings. After a large number of these alternating rows of blocks and moldings has been thusarranged, as closely compressed together as possible, the moldings are then rammed down solidly between the blocks, until it becomes a tight packing, and forms not only a water-tight separation between each row, but also wedges the entire mass closely together. The remaining interstices, if any, may then be filled with concrete, or gravel and tar, or other like substances, in the ordinary manner.

Pavements constructed according to the principles embodied herein are not only unaffected by any and all the contingencies of climate and Weather, and inpervious alike to rain, moisture, and the action of frost, and their durability and usefulness immensely increased by the watertight foundation upon which the blocks rest, and the concrete packing between the separate rows thereof, but also the rapidity and facility with which such pavements can be laid down are greatly increased, the cost of their construction cheapened by the diminished amount of wood required, and which at the same time affords the great additional advantage of securing a firmer footing for the feet of passing animals so long as the pavement shall last. Another great advantage which my pavement possesses arises from the fact that in repairing many streets where cobble or other stone has been used the material for the foundation is directly at hand, thereby cheapening the cost of such pavements.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is The construction of a wooden pavement by placing concrete moldings between each row of blocks of a size and shape corresponding thereto and of any desired thickness, in combination with the Cobble-stone, slag, or rock foundation, and the cement or concrete filling or layer thereupon, substantially in the manner and for the purpose hereinbefore set forth.

. ISAAC H. HOBBS. Witnesses:

W. B. POWELL, B. CLIFFORD DicKsoN.

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