IMPROVEMENTS IN ROCK DRILLS
Year: 1878

page_text: LETTERS PATENT to Ernest de Pass, of Fleet Chambers, 68, Fleet Street, in
the City of London, Patent Agent, for the Invention of " IMPROVEMENTS IN
ROCK DRILLS." A communication from abroad by Arvid Henry Elliott, of
New York, in the United States of America, Gentleman.
Sealed the 12th April 1878, and dated the 14th February 1878.
PROVISIONAL SPECIFICATION left by the said Ernest de Pass at the Office
of the Commissioners of Patents on the 14th February 1878.
ERNEST DE PASS, of Fleet Chambers, 68, Fleet Street, in the City of London,
Patent Agent.
"IMPROVEMENTS IN ROCK DRILLS." A communication from
abroad by Arvid Henry Elliott, of New York, in the United States of America,
Gentleman.
This machine is of the percussive class, and is used either with steam or com-
pressed air. Its valve is moved by air or steam, and in one arrangement the piston
is rotated and the cylinder fed to the rock by hand.
The ordinary D valve is used, but it is made circular, and has at each end a
piston turned to fit the valve box, and is provided with a guide to prevent its
turning around. The valve box has exhaust ports for the valve pistons, and these
ports are carried across and to opposite ends of the valve box, and lead down into
the steam cylinder through suitable openings. From this the exhaust is carried into
the main exhaust port by a groove or recess turned in the piston, and thence by
openings in the side of the cylinder.
The guide for the valve is constructed as follows:- A hole is bored through the
circular-shaped D valve lengthwise, and is slotted through for a portion of the way
to receive a feather, which is let into the bolt passing through the valve. This bolt
answers the several purposes of holding the valve box caps firmly to their places,
of keeping the valve in position, and of affording support to the valve, and thus
lessening its wear on the valve seat. The valve box is supplied with rubber
cushions at each end, which are protected by steel plates, so that the valve strikes
Din 677

page_text: against the face of these plates to which the cushions are clamped, and thus
prevents jamming of the rubber and breakage of the valve from concussion.
The piston carrying the boring bit is of ordinary construction, being a long or
double piston with packing rings at each end, but it has a groove or recess turned
out in its centre for conducting the exhaust steam or air from the valve pistons into
the main exbaust port. The upper end of the piston is bored out to receive a
fluted nut and the fluted bar used for rotating the piston. This fluted bar and feed
screw are made of one piece of steel. The cylinder is carried up and down by a
collar. The screw of the piston passes through a nut fastened to the end of the
tripod, and when the screw is revolved by the crank the cylinder is carried up and
down, as required, and the piston is rotated at the same time.
The tripod is adjustable, and particularly so to quarry work, its legs being
telescopic, and the back leg being hinged so as to give the angle required.
Another method for advancing the cylinder towards the rock as the same may be
cut away by the drilling bit is by an automatic arrangement, which is as follows:-
A shaft is placed upon the outside of the cylinder, and extends from about its lower
end to the top of same. From this shaft a projection or enlargement extends to
the inside of the steam cylinder at its lower end. This projection is bevelled, and
when the rounded edge of the piston comes in contact with it the projection is
forced outward from the inside of the cylinder, and imparts a rotating motion to
the shaft, which in its turn operates a feeding device at the top end of the cylinder
by disengaging a pawl from a rotary feed nut, which nut advances the cylinder
upon a screw in the usual way. When the piston returns upon its upward stroke
the projection upon the shaft is relieved from contact with the piston, and a spring
does the feeding by forcing the pawl against the teeth of the rotary feed nut, and at
the same moment carries the projection back to the inside of the cylinder. It is
evident therefore that if the rock is cut away sufficiently for the piston to descend
against the projection, that in forcing the same outwards the feeding device at the
top is regulated thereby.
To operate the machine the air or steam is turned on and the valve is caused to
move upwards, which opens the main supply port to the lower end of the cylinder,
and at the same time frees the exhaust from the upper end. The piston immediately
rises till it closes the exhaust from the upper end of the valve box, and opens the
connection for the exhaust to the lower end of the valve box, which then allows the
valve to return downwards and supply steam or air to the upper end of the piston,
and thus move the piston to the rock. This movement of the piston closes the.
exhaust from the lower end of the valve box and opens its upper end, causing the
valve to raise and continue the motion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernest de Pass in the Great Seal Patent Office on the 14th August
1878.
ERNEST DE PASS, of Fleet Chambers, 68, Fleet Street, in the City of London,
Patent Agent. "IMPROVEMENTS IN ROCK DRILLS." A communication from
abroad by Arvid Henry Elliott, of New York, in the United States of America,
Gentleman.
This Invention has for object improvements in rock drills, and consists,―
First. In the construction and arrangement of the valve and valve box.
Secondly. In the means employed for controlling the valve by the exhaust from
opposite ends of the valve box, and without such box having any connection with
the steam or air which is in either end of the main cylinder.
Thirdly. In an automatic feeding device for advancing the movement of the
cylinder towards the rock.
And, Fourthly. In the construction and arrangement of a light and adjustable
tripod, specially suitable for quarry work.
The accompanying Drawings represent a rock drill constructed according to the
Invention, the same letters of reference indicating similar parts in all the Figures.
Figure 1 is a side elevation of a rock drill constructed according to one arrange-
ment, and showing the back leg of the improved tripod and the means for adjusting
it; Figure 2 is a front elevation of same.
Figure 3 is a fragmentary vertical section, showing an arrangement for feeding
the cylinder to the rock by hand.
Figure 3 shows the clamping arrangement for the tripod.
Figure 4 is a vertical section of the drill taken on the line a, 3, of Figure 5;
Figure 5 is a top view or plan of same.
Figure 6 shows in detached view in elevation the cylinder with the valve box
removed.
Figure 7 shows the valve box inverted, with the inlet and outlet ports for the
passage of the steam or air.
Figure 8 shows in vertical section on an enlarged scale the valve box, in order
that it may be more clearly seen.
Figure 9 is a horizontal section taken on the line y, z, of Figure 4, and showing
the ports of the valve box and of the cylinder.
Figure 10 is a perspective view of the improved valve.
And Figure 11 is a perspective view of the drill, but mounted on a different
arrangement of tripod to that shewn in Figures 1, 2, 3, and 3*.
This machine is of the percussive class, and is used either with steam or com-
pressed air. Its valve is moved by air or steam, and in one arrangement the
piston is rotated and the cylinder fed to the rock by hand, and in another arrange-
ment an automatic feeding device is employed.
A is a D valve, which is made circular, as shewn in perspective view, Figure 11,
and it has at each end a piston a, a', turned to fit the valve box A'. To prevent
the valve from turning around, a hole is bored through it lengthwise, and is slotted
through for a portion of the way to receive a feather b, which is let into the bolt B
which passes through the valve. This bolt answers the several purposes of holding
the valve box, caps, cushions, and plates firmly to their places, of keeping the valve
in position, and of affording support to the valve, and lessening its wear on the seat.
The valve box A' is provided with exhaust ports c, cx, for the valve pistons, and
these valves are carried across and to opposite ends of the valve box, as shewn by
the dotted lines (Figure 7), and they lead down into the steam cylinder C through
passages d, d. From this point the exhaust is carried by a groove or recess f
turned in the piston E, and thence by the openings g, gx, in the cylinder to the
main exhaust port, and without having any connection with the steam or air which
is in either end of the cylinder. This constitutes a very great improvement in the

page_text: Invention. The valve box is supplied at each end with elastic cushions h, h, pro-
tected by steel plates h*, h*, in order to prevent jamming of the cushions and
breakage of the valve from concussion as the valve strikes against the face of these
steel plates to which the cushions are fixed.
The piston E carrying the drilling bit F is of ordinary construction, being a long
or double piston with packing rings e, ex, at each end, but it has a groove or recess f
turned out in its centre, which recess is used for conducting the exhaust steam or
air from the valve pistons into the main exhaust port, as before described. The
upper end of the piston is bored out to receive a fluted nut G, through which passes
the fluted bar G₁ used for rotating the piston. This fluted bar G¹ and feed screw G³,
as shown in Figures 1, 2, and 3, are made of one piece of steel, but they may be
also made separately and connected together. These parts so constructed form a
very essential feature in the improvements, and the cylinder is carried up and down
by the screw passing through the frame or collar G³. The screw G² also passes
through the nut G, which is fastened to the top of the frame, and when the screw
is revolved by the crank H the cylinder is carried up or down, as required, and the
piston is rotated at the same time.
The principal features of my improved tripod, shown in Figures 1, 2, 3, and 3*,
comprise light weight, simplicity, and cheapness of manufacture. It is intended
chiefly for use in quarries or places where shallow holes are to be bored, and conse-
quently constant shifting of the machine is usually required, therefore a light tripod
and light machine are desirable. On each side of the cylinder there are two lugs or
eyes N, N*, which are bored through to receive the rods P, P, which serve as guides
for the cylinder to be raised or lowered upon. The back leg Z of the tripod is
hinged at to the collar or frame G³, so that it can be moved backwards and forwards,
as desired. It is clamped to a hinged rod Z*, which keeps the back leg firm and
'steady in the position placed. By operating a nut t, seen in Figure 3*, the
clamp tx is made adjustable to any position or angle at which the rod and leg may
be placed; that is, in moving the leg from and to the machine the clamp allows the
rod to slide freely through its bolt t, and at the same time this clamp slides upon
the back leg. The hollow rods Q are used for strengthening the frame, and also
serve to receive the legs of the tripod, which are telescopic; the hind leg is also
telescopic.
R, R, are rests, upon which the operator may place his foot, or weights may be
placed thereon to steady the machine.
The operation of the machine is as follows:-When the air or steam enters the
valve box it is admitted between the valve pistons, and supposing the valve to be
resting against the lower end of the valve box, it will be seen that the exhaust from
this end of the valve box is closed, because the main piston lies over the passage d*,
whilst the other end of the valve box is free to exhaust, because the groove or
recess is in position to leave open the port c through the tube d, and thence from
the recess through the opening g into the main exhaust port D. It follows that
the valve would receive a pressure upon its lower piston, whilst the other end of
the valve could not, therefore the valve must rise, and, in doing so, the main supply
port to the lower end of the cylinder is opened, and at the same time the exhaust
from the upper end being freed the piston immediately begins to rise, and its
recess f, on reaching the exhaust port cx of the lower end of the valve box, allows
the steam or air under the piston a to escape through the tube d*, and thence
through the passage g* into the main exhaust port D. This returns the valve back
to its first position, and, in doing so, the main supply port jx to the upper end of
cylinder is opened, and the exhaust by the lower main port j is freed, which causes
the piston to descend toward the rock, and the groove or recess f, on reaching the
exhaust port c of the upper end of the valve box, allows the steam or air above
the valve piston a¹ to escape through the tube d, and thence through the passage g
into the main exhaust port. This downward stroke of the piston closes the exhaust
from the lower end of the valve box, and opens the upper end, thus causing the
valve to rise and continue the motion.

page_text: It should be observed that the openings g, g*, are connected with the main
exhaust port D by an opening x cast in the cylinder, and which is shown by the
dotted lines in Figure 6.
The small ports i, i*, in each end of the valve box are made so as to extend just
within the valve pistons, and they serve to admit a puff of air or steam to accelerate
the starting of the valve, and as the valve moves from either end of the valve box
these pistons instantly close the ports alternately.
Another method for advancing the cylinder towards the rock, as the same may
be cut away by the drilling bit, is by an automatic arrangement, seen in Figures 4, 5,
6, and 12, which is as follows:-An arm m is fixed to the top of the shaft K, which is
placed upon the outside of the cylinder C, and as arranged extends from the top to
about the lower end of same. On the lower end of this shaft there is a bevelled
projection or enlargement k, which extends inside of the steam cylinder. To the
arm m is hooked a pawl n, which engages in the teeth of a rotary feed nut 8, and
which nut advances the cylinder upon the screw G2 in the usual way. This pawl n
is forced to engage the teeth of the rotary feed nuts by the spring p, which is
constantly pressing against it. When therefore the rounded edge of the main
piston comes in contact with the bevelled projection, it is forced outward from
within the cylinder, and it thus imparts motion to the shaft, which in its turn
operates the arm fixed to its top, and which arm withdraws the pawl and forces it
more firmly against the spring. It is evident therefore that when the piston returns
upon its upward stroke, and passes from off the bevelled projection, that the same
is released, and thereby permits the spring to react and force the pawl to revolve
the feed nut, as also the spring at the same time to return the shaft and its bevelled
projection back to their first position. This bevelled projection is prevented from
entering too far within the cylinder by a stop k*, which is firmly fixed to the shaft,
and which stop also limits the advance movement of the pawl upon the feed nut
as the pawl is pressed upon by the spring.
It will readily be seen that whenever the rock is sufficiently cut away for the
piston to descend against this projection, that in forcing it outward the feeding
device is actuated thereby, and that when the piston returns upon its upward stroke
and releases the projection, that the feeding is then done by means of the spring
reacting upon the pawl.
In other feeding devices the feeding is done when the piston strikes the pro-
jection in its downward stroke, and thus causing a destruction of parts, because the
whole feeding device is forced to operate by means of the blow given. In nine the
reverse is the case, for when the piston passes upon the projection it simply actuates
the feeding device, and the blow is delivered against the force of a spring only, and
I obtain a far better result, both as to regularity and means of rotating the nut, and
in the durability of parts.
Having now described the nature of the said Invention, and in what manner the
same may be performed, I declare that I claim,-
First. Arranging a valve, such as is shewn at A, to move upon a rod or bolt
within its valve box, and providing such bolt or rod with a guide to prevent the
valve from turning around, substantially as herein described.
Second. The use of a rod or bolt, arranged substantially in the manner shewn,
so as to pass through the caps, valve box, cushions, and valve, for the purposes
herein described.
Third. The use of ports, arranged in the valve box substantially in the manner
shewn, being carried across to opposite ends of same, so that the exhaust steam or
air from opposite ends of the valve may be controlled by the groove or recess in
the main piston, as herein described.
Fourth. The means employed for controlling the valve by the exhaust steam
or air from opposite ends of the valve box, and without having any connection
with the steam or air which is in either end of the main cylinder, substantially
as herein described.
Fifth. The use of a fluted rotating bar and screw, formed of one piece of metal

page_text: or connected together, by means of which the feeding and rotation is made one
operation, substantially as herein described.
Sixth. The method of feeding the cylinder to the rock automatically, substantially
as set forth, by means of a spring and pawl, which forces the feed nut to revolve
upon the feed screw, the spring acting on the pawl when the piston (in its upward
stroke) is out of contact with the bevelled projection on the shaft, as herein-before
described.
Seventh. The use of the improved tripod, having its parts constructed and
arranged substantially as herein described, and shewn in Figures 1, 2, 3, and 3× of
the accompanying Drawings.
In witness whereof, I, the said Ernest de Pass, have hereunto set my hand
and seal, this Twelfth day of August, in the year One thousand eight
hundred and seventy-eight.
ERNEST DE PASS. (L.S.)