US479500A - Blasting stone - Google Patents

Description

M 0 G. M. GITHENS. v

BLASTING STONE.

No. 479,500. Patented July 26, 1892.-

UNITED STATES PATENT OFFICE.

GEORGE M. GITI-IENS, OF BROOKLYN, NE\V YORK.

BLASTING STON E.

SPECIFICATION forming part of Letters Patent No. 479,500, dated July 26, 1892.

Application filed January 2, 1892. Serial No. 416,756. (No specimens.)

To all whom it may concern.-

Be it known that I, GEORGE M. GITHENs, a citizen of the United States, residing at Brook lyn, in the county of Kings and State of New York, have invented an Improvementin Blasting Stone, of which the following is a specification.

In blasting out stone in quarries it is desirable to split the stone as nearly straight as possible and to prevent loss of stone resulting from large drill-holes or from powder-cracks.

My present invention is especially available in sandstone-quarries and with other stone that is in layers of greater or less thickness.

In quarrying this character of stone it is usual to drill a range or ranges of holes in the line of cleavage and to drive in plugs or wedges and feathers to split the stone. These, howover,have always been applied at the surface of the stone. Hence the crack has been commenced at the surface and extended downwardly, and where the beds of stone rest firmly one on the other the crack, instead of passing down vertically, often extends diagonally and runs out at the vertical face of the ledge, because this is the line of least resistance. I have discovered that after a hole is drilled to a suitable depth and a sharp chiselpointed drill is driven into the stone at the bottom of the hole and a blast is firedin such hole the stone will be split in the line that is marked by such chisel. This appears to arise from the fact that a crack is started in the stone by the chisel and that the force of the explosion continues this crack; and my present invention relates to the method hereinafter described and claimed for carrying out my invention or discovery.

In the drawings, Figure 1 illustrates by a section of the rock the manner of preparing each drill-hole. Fig. 2 is a similar view with the wedges in place, and Fig. 3 shows a range of holes prepared for firing and at right angles to Figs. 1 and 2.

The drill-holes a. a, are inserted in the line of cleavage, and in sandstone and stones having natural beds or layers these drill-holes are not extended down to the natural bed or seam b, at which the cleavage is to terminate, but such holes are sufficiently above to prevent injury to the strata below the seam. A properly-sharpened drill is now introduced into the holes in succession, and it is marked on one side or so guided that the straight chisel edge of the drill is in the line of the desired cleavage, and this drillis driven down by a suitable sledge or otherwise with sufficient force to embed the chisel edge into the rock, as at c, and thereby commence the line of cleavage. If now powder is introduced into the hole thus prepared and exploded, the rock will be broken in the plane, or nearly so, of the chisel-mark in the bottom of the hole. I avail myself of this feature in carrying out my invention, as follows:

Into a range of holes drilled to the proper depth, as aforesaid, the wedges d d are introduced, and the keys or plugs e are driven in between them. This is preferably accomplished by small charges of powder in each hole, exploded simultaneously by electricity or otherwise. I have shown the powder at f, which may be in canisters or poured into the hole above wads g, resting on top of the tapering plugs e, and it is usually advantageous to leave air-spaces in the holes above the powder and to plug the upper ends of the holes.

By this improvement the crack is commenced at c and continues down to the bed or seam b and tends to lift the rock as it is split from the bed, and the split continues upwardly to the top, and the piece of stone is thus split with accuracy and'moved bodily outwardly on the uninjured bed-rock, and the extent of movement given to the rock depends on the quantity of powder, and when cleavage is effected in the same manner, and

the wedges are operateduntil the stone is moved off bodily and the crack opened at the top the desired distance.

In consequence of the cleavage being commenced at the bottoms of the holes and near the bed or seam there is a lifting action to lift the stone from the bed instead of forcing the stone down upon the bed, as is the case when the splitting action is commenced near the top of the stone. The wedges are not materially injured by use and can be recovered after the stone is sufficiently removed.

In the usual manner of firing explosive ma terial in a blast the pressure is uniform and radial and the cleavage is in the line of least resistance and the downward pressure at the bottom of the hole is valueless in the splitting operation. By placing the wedges in the bottom of the hole the downward pressure is availed of in splitting the stone in the line of cleavage thatis predetermined by the position of the wedges.

I claim as my invention 1. The method herein specified of splitting stone, consisting in drilling a hole into the stone to the place Where the cleavage is to be commenced, then driving a straight-edged chisel into the stone at the bottom of the hole to start a fracture in the line of cleavage, then continuing the separation by pressure within the hole, substantially as set forth.

2. The method herein set forth of splitting stone, consisting in drilling holes into the stone in the line of cleavage, driving into the stone at the bottom of each hole a chisel to start the fracture in the line of cleavage, and continuing the splitting action by wedges Within the bottoms of the holes, substantially as set forth.

3. The method herein set forth of splitting stone, consisting in drilling holes into the stone in the line of cleavage,driving into the stone at the bottom of each hole a chisel to start the fracture in the line of cleavage, and introducing into such holes wedges and explosive material to act on such Wedges and split the stone, substantially as set forth.

Signed by me this 30th day of December, 1891.

GEO. M. GITI-IENS.

Witnesses:

GEO. T. PINOKNEY, ALICE M. OLIVER.

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