5-0 6< 7/3 



1855.] 



ON AN EARTH-BORING MACHINE. 



297 



TORONTO, AUGUST, 1855. 



On an Earth-Borin?: Machine. 



BV COLIN MAIUEll.* 



The construction of Mr. Mather's new boring-head and shell- 

 pump, and the mode of acquiring the percussive motion, con- 

 stitute the chief novelties of the system and machine. The 

 couple-cylinder engine, with the reversing or link motion, is 

 used for winding and lowering apparatus; but an ordinary 

 winding engine, similar to those used in collieries, may be applied. 



The boring-head consists of a wrought-iron bar, about eight 

 feet long, on the lower part of which is fitted a block of cast- 

 iron, in which the chisels or cutters are firmly secured. Above 

 the chisels an iron casting is fixed to the bar, by which the 

 boring-head is kept steady and perpendicular in the hole. A 

 mechanical arrangement is provided, by which the boring-head 

 is compelled to move round a part of a revolution at each 

 stroke. The loop or link by which the boring apparatus is 

 attached to the rope is secured to a loose casting on the wrought- 

 iron bar, with liberty to move up and down about six inches. 

 A part of this casting is of square section, but twisted about 

 one-fourth of the circumference. This twisted part moves 

 through a socket of corresponding form on the upper part of a 

 box, .in which is placed a series of ratchets and catches, by 

 which the rotary motion is produced. Two objects are here 

 accomplished — one the rotary motion given to the boring-head, 

 the other a facility for the rope to descend after the boring- 

 head Las struck, and so prevent any slack taking place, which 

 would cause the rope to dangle against the side of the hole, 

 and become seriously injured by chafing. 



The shell-pump is a cylinder of cast-iron, to the top of which 

 is attached a wrought-iron guide. The cylinder is fitted with 

 a bucket similar to that of a common lifting-pump, with an 

 India-rubber valve. At the bottom of the cylinder is a clack, 

 which also acts on the same principle as that in a common 

 lifting-pump, but it is slightly modified to suit the particular 

 purpose to which it is here applied. The bottom clack is not 

 fastened to the cylinder, but works in a frame attached to a 

 rod which passes through the bucket, and through a wrought- 

 iron guide at the top of the cylinder, and is kept in its place 

 by a cotter, which passes through a proper slot at the top of 

 the rod. The pump-rod, or that by which the bucket is worked, 

 is made of a forked form, for the two-fold purpose of allowing 

 the rod to which the bottom clack is attached to pass through 

 the bucket, and also to serve as the link or loojj by which the 

 whole is suspended. 



The wrought-iron guide is sccui'cd to the top of the cylinder, 

 and prevents the bucket from being drawn out when the whole 

 is so suspended. The bottom clack also is so arranged that it 

 is at liberty to rise about six inches from its seating, so as to 

 allow large fragments of rock, or other material, to have free 

 access to the interior of the cyliniler when a partial vacuum is 

 formed there by the up-stroke of the pump. 



The percussive motion is jjrodueed by means of a stoani- 

 cyliiider, which is fitted with a piston of 15 inches diameter, 

 having a rod of cast-iron 7 inches square, branching oft' to a 



* .Iniirnnl of the Society of Arts. 

 Tor,. TTT,, Xn. l.S, August, 1R55, 



fork in which is a pulley of about three feet in diameter, of 

 sufficient breadth for the rope to pa.ss over, and with flanges to 

 keep it in its place. As the boring-head and piston will both 

 fall by their own weight when the steam is shut off, and the 

 exhaust-valve opened, the steam is admitted only at the bottom 

 of the cylinder ; the exhaust-port is a few inches higher than 

 the steam-port, so that there is always an elastic cushion of 

 steam of that thickness for the piston to fall upon. 



The valves are opened and shut by a self-acting motion 

 derived from the action of the piston itself; and as it is of 

 course necessary that motion should be given to it before such 

 a result can ensue, a small jet of steam is allowed to be con- 

 stantly blowing into the bottom of the cylinder ; this causes 

 the piston to move slowly at first, so as to take up the rope, 

 and allow it to receive the weight of the boring-rod by degrees, 

 and without a jerk. An arm which is attached to the piston- 

 rod then co.nes in contact with a cam, which opens the steam- 

 valve, and the piston moves quickly to the top of the stroke. 

 Another cam, worked by the same arm, then shuts off the 

 steam, and the exhaust-valve is opened by a corresponding 

 arrangement on the other side of the piston rod. By moving 

 the cams, the length of the stroke can be varied at the will of 

 the operator, according to the material to be bored through. 

 The fall of the boring-head and piston can also be regulated 

 by a weighted valve on the exhaust-pipe, so as to descend 

 slowly or quickly, as may be required. 



The general arrangement of the new machine may be des- 

 cribed as follows : — 



The winding drum is 10 feet in diameter, and is capable of 

 holding 3,000 feet of rope, -tj inches broad and half an inch 

 thick ; from the drum the rope passes under, a guide-pulley, 

 through a clam and over the pulley which is supported on the 

 fork end of the piston-rod, and so to the end which receives 

 the boring-head, which being hooked on and lowered to the 

 bottom, the rope is gripped b}' the clam. A small jet of steam 

 is then turned on, causing the piston to rise slowly until the 

 arm moves the cam, and gives the full charge of steam ; an 

 accelerated motion is then given to the piston, raising the 

 boring-head the required height, when the steam is shut off, 

 and the exhaust opened in the way described, thus effecting 

 one stroke of the boring-head as regulated by a back-pressure 

 valve in the exhaust-pipe. The exhaust-port is six inches 

 from the bottom of the cylinder; when the piston descends to 

 this point, it rests on a cushion of steam, which prevents any 

 concussion. To increase the lift of the boring-head or com- 

 pensate for the elasticity of the rope, which is found to be one 

 inch in one hundred feet, it is simply neccs.sary to raise the 

 cams on the cam-shaft whilst the percussive motion is in ope- 

 ration. The clam which grips the rope is fixed to a slide and 

 screw, by which moans the rope can be given out as required. 

 When this operation is completed, and the strata cut up by a 

 succession of strokes thus effected, the steam is shut off from 

 the percussive cylinder, the rope undamped, the winding-engine 

 put in motion, and the boring-head brought up and slung from 

 an overhead suspension bar by a hook fitted with a roller to 

 traverse the bar. The shell-pump is then lowered, the (/r'hn's 

 pumped into it, by lowering and raising the bucket about three 

 times, which the reversing motion of the winding-engine 

 reailily admits of; it is then brought to the surface and emptied 

 by the following very simple arrangement. At a point in the 

 suspension-bar a hook is fixed perpendicularly over a small 

 table in the waste-tank, which table is raised and lowered by a 

 screw. The pump being suspended from the hook hangs 

 diroctlv over the table. whi<'li is then raised by the screw till 



