IMPROVEMENTS IN MACHINERY FOR BORING, CUTTING, AND WORKING ROCK AND OTHER HARD SUBSTANCES, CHIEFLY DESIGNED FOR MINING, TUNNELLING, AND OTHER LIKE OPERATIONS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by William Henry Cope at the
Office of the Commissioners of Patents, with his Petition, on the
6th March 1872.
I, WILLIAM HENRY COPE, of Old Gravel Lane, St. George's-in-the-
East, in the County of Middlesex, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MACHINERY FOR BORING, CUTTING, AND
WORKING ROCK AND OTHER HARD SUBSTANCES, CHIEFLY DESIGNED FOR MINING,
TUNNELLING, AND OTHER LIKE OPERATIONS," to be as follows:-
My Invention relates to improvements in that class of rock boring
machines which operate by the percussive action of the drilling or boring
tool, which is attached to a reciprocating piston worked by the pressure
of steam or compressed air.
The Invention consists chiefly in the method of operating the valve
which governs the distribution of steam or air to the cylinder in which
the piston works, and in the means whereby the advance or
"feed"
of the drilling apparatus is effected automatically as fast as it penetrates
the rock.
As the speed of penetration differs according to the varying nature
of the material operated upon the "feed" must be regulated accordingly,

page_text: which is accomplished by my Invention in a self-acting manner, and
the action of the apparatus is rendered unfailing, no matter how fast
or how slow it may be driven.
The body of the machine consists of a cylinder cast with wings at
the sides fitted to work in guides in the bed or carriage of the machine,
which is pivoted in a box or bearing provided with a clamp to fit on
a cylindrical bar, which may be fixed in any convenient position, the
machine being capable of operating in any direction.
The valve which governs the distribution of steam or air to the rear
side of the piston may be an ordinary D valve or slide moving over two
ports, one for the admission of steam to propel the drill forward, and
the other for the exhaust. It is operated to cut off the supply of
steam or air by a cam of particular form, which acts against the end of
the valve rod, the latter being constantly kept up to the surface of the
cam by the pressure of the steam or air in the valve chest. This cam
is driven by a pair of very small oscillating cylinders supplied with
steam or air and working entirely independent of the movements of
the main piston, the office of these cylinders, whose pistons are connected
direct to the cam, being solely to operate the said valve. The form
of the cam is such that the cut off is, so to speak, gradual, an almost
entire revolution of the cam being required to effect this, whilst the
return .movement of the valve to admit the steam or air takes place
almost instantaneously. This differential movement of the valve has
an important effect on the working of the machine, being peculiarly
adapted to augment the intensity of the blow given by the drill. The
steam or air is constantly admitted to the front side of the main piston
to operate its return stroke, the pressure being overcome on the forward
stroke by the pressure on the other face of the piston, which is of
considerably greater effective area. The piston is partially rotated
at each stroke of the drill as usual, in order that the latter may not
strike each time in the same place. This movement is imparted to it
by the cam before mentioned through the medium of a pawl gearing
with a ratchet wheel fitted on a boss or sleeve, through which the piston
rod passes with a groove and feather connection to allow of its to-and-fro
movement.
To avoid damage to the ratchet wheel, should the drill be obstructed
on its return stroke by any loose piece of rock which would prevent
its turning in the hole, the sleeve or boss on which the wheel is fitted

page_text: is made slightly tapered or conical at that part, and the ratchet wheel
is held thereon merely by the friction of the two conical surfaces, so
that the wheel would slip when the rotation of the drill is obstructed as
before mentioned. The wheel may be tightened up by a nut applied
to the end of the sleeve. The advance or feed of the drill is effected in
the following manner :-Beneath the cylinder is mounted a screw shaft
revolving in bearings in the lower carriage, and on the under side of
the cylinder casting are two lugs or ears bored to fit the outside diameter
of the screw, between these two lugs a long nut revolves screwed to
suit the shaft. On this nut two forked levers are mounted so as to
be capable of oscillating freely thereon. These levers are placed at an
angle to one another at a distance apart equal to the greatest travel of
the piston and they are rigidly connected together in this position at
the extremities of their arms by two rods between which the piston rod
passes. These rods are inclined obliquely to the axis of the piston owing
to the relative positions of the levers which form with the rods an
oscillating frame operated by the reciprocating movement of a collar.
on the piston rod which moves up and down between the obliquely
placed rods. On this forked lever or frame is a spring pawl catching
in the teeth of a ratchet wheel fast to the nut, whereby the nut is rotated
to the extent of one tooth of the ratchet wheel by the backward stroke
of the piston when the same is working full stroke, the degree of obliquity
of the said rods being only sufficient to enable the pawl to engage with
another tooth and advance the machine the distance the drill has
penetrated when the piston has made a full stroke forward, so that should
the drill be prevented by the hardness of the rock penetrating to its full
depth at cach blow the percussive action will be continued till the full
stroke be attained, when the advance movement will recommence. The
motions of the drill in advancing are therefore perfectly automatic, no
matter whether the rock be hard or soft through which it is desirable
to bore. The screw shaft is rotated by hand to bring back the machine,
and is secured by a check nut when working forwards.
This improved machine may also be applied to other operations, such
as dressing stone for instance.