QUARRYING MACHINERY. The most important improvement in quarrying appli ances made within the decade is the general adoption of the channeling process, which has been rendered possible by the improvements made in channeling machines. The channeling process is a means by which artificial seams are made in the quarry for the purpose of releas ing masses of stone. An intelligent and proper use of the channeling process does not in volve the cutting up of stone in blocks as ice is harvested. but its use is to release a large mass or bed in such a way that by the action of plugs and feathers, wedges, or by blasting, the stone may be entirely freed in the quarry. It is only while cutting out the key block that all four sides of a block of stone are channeled. If there is a free bed on the bottom—that is, if the stone is laid in layers deposited one upon the other—it is simply necessary to channel around the walls of the quarry, because by means of the plug and-feather process, or by blasting, the blocks of stone may be sheared on the bed. Where there are no free beds the channels are cut around the walls and directly across the quarry in parallel rows.
The Wardwell Channeler, illustrated and described under " QuariTing Machinery," Vol, II. of this work, having come into extensive use, is manufactured in at least half a dozen different factories in different sections of the United States. The general design and con struction have not materially changed, the improvements which have been made being only matters of detail.
The Bryant Channeler, Fig. 1, is constructed on the bas s of the Wardwell machine, but differs in the method by which the work is accomplished, and contains several useful improve ments. The principle is differ ently applied from the Ward well, for while the side arms of the Wardwell are bifurcated, or forked, working with one rub ber between the forks and one on top, with stirrups to shackle them together. in this machine the lever consists of two arms opposing each other, working on a common fulcrum, with rubbers or steam cushions on both sides of fulcrum working freely, without stirrups. The cups holding the rubbers may be moved at more or less dis tance from the fulcrum, thus admitting close adjustment to the elastic condition of the rub ber or variation of the blow.
The levers are hung on a mov able fulcrum, being placed in a hanger, which may be raised or lowered by means of a screw, and retained in position by guides which are bolted to the frame. This admits of the feeding of drills down as the cutting proceeds, and also of the dropping of levers, without the compression on the rubbers. When both gangs are running on a 60 or 100-ft. run, the operator is enabled to keep the machine in continuous motion until he has sunk 15 or 20 in. The guides for the clamp as arranged for limestone are similar to those used in the Wardwell, with the exception that they are continuous from bottom to top and admit the drills being brought down till the top clamp touches the bottom clamp. The propelling end of the lever is operated from the main shaft by a disk connected by a sliding box and movable wrist-plate. This changeable wrist-plate admits a change of stroke from 4 to S in ., and may be placed on the center when it is only wanted to operate one side. The propelling gear is operated by a reverse-motion friction clutch on the crank shaft geared to a shaft that connects with both sets of trucks by worms and worm gears. This arrangement holds the machine at any point when working on a slope. The friction clutch is not so positive as to force the machine against an obstruction, but will slip when the pressure comes too hard on it. It will work on an incline of 1 ft. in 10 with safety. Where the incline is too steep, a dram on one of the axle-trees is used of the same size as the tread of the wheel, with a wire rope attached to it, and made fast to a plug at the upper end of the cut. This is wound upon the spool going up, and unwound coming down, making a positive feed. Four cutters are used in a gang of drills in sandstone. The two outside drills are chisel-shaped points, cutting at right angles with the channel. The two inside drills cut diagonally across the channel'. The speed on the track is three-quarters of an inch at every stroke, and may be 200 revolutions with both sides working all the time. With the four drills the bottom of the channel is kept smooth and free from "frogs." The frame is constructed of channel steel and steel I-beams, bracketed together with malleable iron brackets and boiler rivets.