US315740A - Construction of pavements - Google Patents

Description

(No Model.)

s. W. GRAGG. CONSTRUCTION 01? PAVEMENT-S..

No. 315,740. Patented Apr. 14, 1885.

' UNITED 'STATES PA'rrnNr @Priora SAMUEL XVILKINS CRAGG, OF BALTIMORE, MARYLAND.

CONSTRUCTION OF PAVEMENTS.

SPECIFICATION forming part of Letters Patent No. 315,740, dated April 14, 1885.

Application filed June 10, 1884. Renewed March 13, 1865.

in Span September 26, 18:91, No. 6,075.

(No modehl Patented in France April ill, 18S-i, No. 149,126, and May-l,

No. 16,815; in Austria August :'12, 138i, Ill/1,483, and

To @ZZ whom, may concern:

Be it known that l, SAMUEL Wi LnrNs CBAGG, of the city of Baltimore, State of Maryland, have invented certain Improvements in the Construction of Pavements, of which the following is a specication.

The object of this invention is to reduce the cost of wood pavements Without affecting their efficiency, and to provide various advantages, hereinafter set forth, not procurable by any of the systems heretoforein use. In wood pavements as heretofore constructed the blocks employed are all of the same dimensions-that is to say, each block is of the same length, breadth, and thickness as all the other blocksthese blocks being placed endwise on a foundation having a smooth or even surface. Therefore the blocks used at the sides of a street, or in proximity to the curbs, are just as long or deep as those in the middle or at any other part of the road-that is to say, each block projects upward from the surface of the concrete or other bed an equal dist-ance. The consequence is that the strength of the pavement is the same at those portions thereof which are subject to slight wear as at the portions Which are subject to considerable wear, and as an example of the disadvantage of this arrangement it may be statedthat in very narrow streets and upon bridges there are certain parts of the roadway which are never used either by horses or wheels. It will, therefore, be understood that in such cases there is a useless consumption of valuable material-i. c., wood, When Wood is used.

My invention consists in employing blocks of different length-that is to say, blocks which, when placed on end in the position they arey to occupy, will not all extend to the same depth 5 also, in constructing the bed in a special manner suitable for the reception of such blocks, as hereinafter described.

In carrying my said invention into practice I provide afoundation or bed of concrete or other suitable material, made in longitudinal tiers or sections of different heights, so that while the upper surface of the roadway will be smooth and even and will conform to the curve given to the foundation, the blocks forming the said surface will be long or short u vertically, according to the section of the bed y upon which they are placed. For instance, the surface of the foundation in the center of the roadway is at a low level to admit the longest or deepest blocks being placed at that 5 part, and on each side of this central portion toward the curbs there are other sections arranged at higher levels, so as to take blocks shorter or of a less depth when on end at parts where the traffic is not so heavy. Any eonvenient number of such longitudinal sections may be employed according to the require ments in any ease.

In order to obtain a perfect adjustment of the top surface, I spread over the surface of 6 the different sections thus prepared a very thin layer of dry cement, sawdust, asphalt, or other material in tine powder. These yielding substances, besides facilitating a perfect adjustment of the top surface, allow liquid cement or asphalt poured on the blocks to run in around and under the same by being absorbed by the dry powdered material. It will thus be seen that by my invention I am enabled to adj ust t-he depth of the blocks according to the eXi- 7 gencies of the traffic of different portions of the transverse area of the road.

A further advantage of my invention is that repairs are facilitated, as one section that is Worn may be readily repaired Without inter- 8 fering with any other section which is still serviceable, whereas by reason of the uniformity of the blocks in pavements as heretofore made, it is difficult to repair one part without taking up the whole. Moreover, by means of my system of making the foundation I am enabled to build each section separately. For example, in wide roads the central section may bemade first, leaving the two sides open to traffic. The longitudinal sections of thefoundationare much more readily made than the Wide single curve ordinarily used, which requires the services of expert engineers; and another feature in favor of my invention is that instead of having to eXcava-te the roadway to the same depth entirely across, as heretofore, I need excavate to the full depth only at the center.

In the further description of my said invention which follows, reference is made to the accompanying drawings, forming a part hereof, and in which- Figure I is atransverse section of a streetpavement, showing the length or depth of the sections of the blocks as decreasing toward the curbs. Fig. II is a similar view of a much narrower street or single bridge, with sections of `blocks and foundation arranged differently.

Referring to Fig. I, A, B, and C are the blocks resting on a foundation preferably of concrete. The blocks A have the greatest depth and form the central section of the pavement, and the blocks B, which are of less depth than the ones A, the first of the side sections. The blocks C, which have the least depth, adjoin the curbs E.

In Fig. II, which represents a much narrower street than the one shown in Fig. I, the blocks A form the central section, and the blocks B are placed next to the curbs. The

blocks of least depth, C, are situated between the deeper sections.

I am aware that in wood pavements blocks of different sizes have been arranged so that blocks of about the same circumference or area 1 of cross-section are laid in the same row, the rows extending transversely or diagonally of the street, or the blocks arranged in groups, the smaller blocks being placed on a higher foundation'than the larger ones, and then rammed down to give them a more solid foundation or bed, and such construction and arrangement of blocks I do not claim; but I am not aware that wood blocks have been arranged in sections of different depths extending longitudinally of the road or street, for the purpose described.

I therefore claim as my invention- 1. In a wood pavement, the foundation thereof made of concrete or other suitable material, in tiers or sections of different heights, which extend longitudinally of the road-bed or street, substantially as and for the purpose specified.

2. In a wood pavement, the blocks thereof of different lengths or depths, arranged in tiers or sections which extend longitudinally of the purpose specified.

SAMUEL WILKINS CRAGG. Witnesses:

GEORGE WALKER, EDWIN AGOSTINI.

road-bed or street, substantially as and for the ,g

Images