ROCK-EXCAVATING MACHINERY. In quarrying the most important machines are the channeler, the gadder, rock drill, air com pressor, etc. To meet the varying requirements of different classes of work four styles of track channelers are manufactured.
Upright Channeler.— This consists of a truck mounted on four flanged wheels running on a track. Upon this track is carried a boiler (in the steam driven machine) or a reheater (in the air driven channeler) together with a pow erful chopping engine mounted at one side on a frame of great strength. At the end of the piston rod of this engine are connected cutting steels which are driven against the rock by steam or air power in the engine cylinder.
Swing-Back Track Channeler.— In ma chines of this type, the frame carrying the cut ting engine swings on a hinge joint, giving an angular adjustment up to 45 degrees from the vertical in the bare machine, or 15 degrees in the outfit carrying the boiler or reheater. In addition to this movement the cutting engine swings in the plane of the frame, with an angu lar range up to 45 degrees either side of the vertical.
Undercutting Channelers.— These consist of a heavy frame of cast iron mounted an four wheels, carried on steel axles running in bab bitted boxes. At either end of the frame is a special guide shell provided with a swinging adjustment in both horizontal and vertical planes, by means of which all angular condi tions may be met and cuts carried clear into the corners. The shells are hung very low, thus giving the least possible offset in cutting. The use of the two shells permits the channeler to work close to the wall and adapts the machine to deposits of any angle or dip.
The bar channeler consists of a carriage sup porting the cutting engine mounted on two parallel bars along winch it is moved auto matically by means of an engine actuating a traveling feet nut. The engine is automatically
reversed at each end of the travel; or the stops may be set at any intermediate point.
The quarry bar consists essentially of the single bar mounted on four tripod legs, two on either end. On the bar is mounted a carriage which supports the drill and which may be moved along the bar by means of ratchet and pinion and operated by a hand wheel.
The gadder consists of a heavy solid cast iron body mounted on four wheels forming a truck running close to the floor of the quarry. To one end of the truck is hinged a standard or arm which can be swung from nearly hori zontal to vertical and firmly locked in any de sired position. On the swinging arm or stand ard is a sliding carriage on which may be mounted, by means of a cone pivot and bolt, any one of several sizes of rock drills, accord ing to the work to be done. To raise or lower the drill and move it along the slide a chain is attached to the saddle and run up and over a shaft at the end of the swinging arm and down to a small drum on which it is wound by turning a crank conveniently placed for the operator. A special taper gib or wedge clamp is fitted on the saddle, wherewith the saddle is firmly locked to the swinging arm by simply throwing down a small lever when the drill has been raised or lowered to the proper posi tion. At each corner of the truck frame is a large pointed steel pin or pointer, slipping freely in a guide socket, and when the machine is properly arranged a blow from a sledge on each of these pins anchors the trucks in place. See Ant COMPRESSOR; Rocs DRILLS; PUMPS, COMPRESSED AIR; PNEUMATIC TOOLS; MINING AND MILLING MACHINERY; COAL MINING MA CHINERY; CRUSHING AND GRINDING MACHINERY; QUARRYING; ROCK DRILLS; TOOLS, ETC,