Rock-drill.
A tool for boring rock by a chisel movement or rotary motion.
Fig. 4376 shows several forms of rock-drills, embracing some of the peculiar features of this tool.
Many varieties may be found not here shown, but these are representative.
See also under artesian-well; well-boring, etc.
a has four cutting edges, arranged radially.
b. The drill-stock has a central cutter and removable, reversible, radial cutters with extended edges.
The shanks of the cutters are retained by a sleeve and key in the longitudinal recesses of the drill-stock.
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1957]
c has a central drill and four circumferential reamers to enlarge and trim the hole.
d is a drill of fast and movable flat chisel-formed cutters combined in one stock, in such a way that the movable cutter will be the leading cutter, and, after it has made its stroke, will receive a blow on its top end from the descent of the fast cutters, thereby driving it past them into the rock.
e has a central cutter operating in a tube which forms a sandbucket.
f has serrated sections, a collar and oblique grooves on the stock, so that as the shaft is lifted for a stroke, it is turned, causing the cutting face to descend in a new place, and turning the drill without the revolution of the stock.
g is a rock-drill of tubular form, and has on its face sets of cutting edges so arranged that the edges of one set may strike the rock across the incision made by the edges of the adjacent set.
h is designed to remove broken and pulverized rock from the bore of a well, and collect it in the drill-rod, at the same time discharging the water from the rod, so as to allow the heavier matters to be retained in the rod, until the receptacle there provided for them is filled.
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Rock-drills. |
i is an expanding drill; when it is drawn upward the cutters fall together and become contracted to a compass less than the diameter of the pipe within which the drill works; but when it is forced downward the cutters are forced outward in radial directions to a diameter greater than the pipe, and therefore cut a path for the pipe.
In
j the drill-stock is hollow, and is designed to be provided with hose attachments for the purpose of introducing water under pressure into the hollow part of the drill-stock, in order to have the water issue therefrom through suitable apertures, to free the drill of the boring meal and remove the same by the overflow of the water.
k is a conical-pointed borer, having three curved cutting faces at equal distances around its point, and is connected with the base of a hollow cylinder by a socket-joint; its curved cutting faces take a spiral form and are continued up to the top of the cylinder, thereby forming parallel spiral grooves on the outside of the cylinder; the edges of the spiral grooves act as reamers, the grooves form elevators in which the silt is raised nearly to the top of the cylinder, where the grooves are intersected by openings which admit the silt to the inside of the cylinder, from which it is discharged, when full, by raising the instrument from the well and removing the borer.
l is an annular reamer whose face is armed with black diamonds or sapphires.
See diamond-drill.
m is a tool for making an enlarged chamber at the bottom of a shaft.
It has a pair of chisel bars coupled by pivots and spreading laterally by the weight imposed.
