IMPROVE MENTS IN ROCK-BORING MACHINES
Year: 1879

page_text: LETTERS PATENT to Edward Thomas Hughes, of the Firm of Hughes and Son,
Patent Agents, 123, Chancery Lane, London, for the Invention of " IMPROVE
MENTS IN ROCK-BORING MACHINES." A communication from abroad by
William Frederick Heshuysen, of Amsterdam, Holland.
PROVISIONAL SPECIFICATION left by the said Edward Thomas Hughes at
the Office of the Commissioners of Patents on the 13th September 1879.
EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents,
123, Chancery Lane, London. "IMPROVEMENTS IN ROCK-BORING MACHINES." A
communication from abroad by William Frederick Heshuysen, of Amsterdam,
Holland.
This Invention relates to improvements in machines in which compressed air is
used for boring rocks or other hard substances, and has for its object to obviate as
much as possible the injury caused to such machines by the repeated shocks and
vibrations to which they are subjected.
The improvements consist,-
Firstly. In the special construction and arrangement of the piston which com-
presses the air, in such a manner that when the rebound, caused by the drill hitting
the rock or other hard substance takes place, the drill bar can freely go back
without undue resistance or strain.
Secondly. In preventing the piston from striking the bottom of the cylinder
when the blow is given, and
Thirdly. In the arrangement for feeding the drill in proportion to the hardness
of the rock or other substance.
A cylinder of ordinary construction is used, to which the atmosphere is freely
admitted through holes in its circumference, and which is closed at the top and
bottom, circular holes being left therein for the passage of the tubes. The
cylinder is supported by a frame, and its piston for compressing the air is made in
two distinct parts, the upper part with leather cup is fixed on the upper tube, and
the under part on a similar tube. The drill bar which passes through the inside of
the tubes is partly plain, and partly cut with a screw thread.
To compress the air in the upper part of the cylinder, the upward motion of the
piston is caused by the rotation of an axle mounted in suitable bearings in the

page_text: frame and furnished with two cams which act upon a block fixed at the end of the
lower tube. At the moment when one of the cams leaves the block the com-
pressed air is free to expand, and causes the blow for perforating the rock or other
substance.
The first improvements are obtained by making the piston in two distinct parts,
the upper part fixed on the upper tube has on the outer end of the latter a nut,
with an internal thread corresponding with that on the drill bar. These three
parts, viz., the drill bar, the upper tube with its nut and the upper part of the
piston form together one mass to which the under part of the piston with its tube
and block transmits the upward motion, and which rebounds freely at the
moment when the drill hits the rock or other substance, finding no other obstacle
than the ordinary atmospheric pressure, consequently the vibration is not com.
municated to the other parts of the machine.
To prevent the piston from striking the bottom of the cylinder at the termi-
nation of the down stroke a conical hole is made near the bottom of the cylinder,
to which hole is fitted a safety valve regulated by a spring and nut. As soon as
the piston passes the air holes in the cylinder during the downward motion the
air is compressed in the bottom part of the cylinder, and by regulating the safety
valve, an air cushion is maintained of sufficient elasticity to prevent the piston
reaching the bottom of the cylinder, and the second improvement is thereby
effected.
In carrying out the third improvement for regulating the feeding of the drill bar
it must be observed that the friction of the cams on the block gives an axial
motion to the lower tube and the under part of the piston. This axial motion is
communicated to the upper part of the piston by the screws, which fix the upper
tube thereto and pass through corresponding holes in the under part, the whole
upper mass in consequence following the axial motion. A friction ring is provided
fixed on the axle of the machine, and formed with two swelling parts corresponding
with the angle which is formed by the line of the ends of the cams with the line
from the centre of the axle to the point of contact of the cams with the block
before mentioned on the end of the lower tube.
On the inside of the frame is fixed a double lever, at one end of which is a
friction roller, and at its other end a half ring fitting the outside of the drill bar.
By the rotation of the axle during the time of contact between the swelling
parts of the friction ring, and the friction roller of the double lever the drill bar
will be kept tight, and being thereby unable to follow the axial motion of the mass
caused by the action of the cams, the nut on the top of the upper tube will
consequently go back, and so create the feeding.
By means of a slot in the friction ring the screw which fixes the latter to the
axle can be adjusted, so as to lengthen or shorten the surface of friction of the
lever, and thereby regulate the extent of feeding given to the drill bar.
On the axle may be fixed fly wheels furnished with handles for working the
machine by hand, or pulleys may be used for working by steam or other power.
Eyes or rings are provided to receive a bar for giving to the machine any desired
inclination, the other end of the bar being fixed on a cross bar of the frame.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Thomas Hughes in the Great Seal Patent Office on the 12th
March 1880.
EDWARD THOMAS HUGHES, of the Firm of Hughes and Son, Patent Agents, 123,
Chancery Lane, London. "IMPROVEMENTS IN ROCK-BORING MACHINES," A com
munication from abroad by William Frederick Heshuysen, of Amsterdam, Holland.
This Invention relates to improvements in machines in which compressed air is
used for boring rocks or other hard substances, and has for its object to obviate as
much as possible the injury caused to such machines by the repeated shocks and
vibrations to which they are subjected.
The improvements consist, Firstly, in the special construction and arrangement of
the piston which compresses the air in such a manner that when the rebound,
caused by the drill hitting the rock or other hard substance takes place the drill
bar can freely go back without undue resistance or strain.
Secondly. In preventing the piston from striking the bottom of the cylinder
when the blow is given, and,-Thirdly. In the arrangement for feeding the drill
in proportion to the hardness of the rock or other substance.
On the accompanying Drawing, Figure 1 is a side elevation of the improved
machine; Figure 2, a section thereof on line A, B, in Figure 1; Figures 3 and 4,
front and back views respectively; Figure 5, section on line C, D, Figure 2 ;
Figure 6, section on line E, F, Figure 2; Figure 7 section on line G, H, Figure 2;
and Figure 8, section on line I, K, Figure 2.
A cylinder a of ordinary construction is used to which the atmosphere is freely
admitted through holes a¹, and which is closed at the top and bottom, circular
holes being left therein for the passage of the tubes d and d¹. The cylinder a is
supported by a frame C, and its piston for compressing the air is made in two
distinct parts. The upper part c with leather cup is fixed on the tube d, and the
under part c¹ on a similar tube d. The drill bar which passes through the inside
of the tubes d and d¹ is partly plain and partly cut with a screw thread as shown.
To compress the air in the upper part of the cylinder a, the upward motion of
the piston c, cl, is caused by the rotation of an axle e mounted in suitable bearings
in the frame C and furnished with two cams f, f, which act upon a block g fixed at
the end of the tube d. At the moment when one of the cams f leaves the block g
the compressed air is free to expand, and causes the blow for perforating the rock
or other substance. The first improvements are obtained by making the piston c, c¹,
in two distinct parts; the upper part c fixed on the tube d has on its outer end a
nut h with an internal thread corresponding with that on the drill bar. These
three parts, viz., the drill bar, the tube d with its nut h, and the upper part of the
piston c form together one mass to which the under part of the piston c' with its
tube d¹ and block g transmits the upward motion, and which rebounds freely at
the moment when the drill hits the rock or other substance, finding no other
obstacle than the ordinary atmospheric pressure, consequently the vibration is not
communicated to the other parts of the machine.
To prevent the piston c, c¹, from striking the bottom of the cylinder a at the
termination of the down stroke a conical hole is made near the bottom of the
cylinder a, to which hole is fitted a safety valve regulated by a spring and nut,
as shown in Figure 5. As soon as the piston c, c', passes the air holes a¹, during
the downward motion the air is compressed in the bottom part of the cylinder, and
by regulating the safety valve k, an air cushion is maintained of sufficient elasticity
to prevent the piston c, c¹, reaching the bottom of the cylinder a, and the second
improvement is thereby effected.
In carrying out the third improvement for regulating the feeding of the drill bar,
it must be observed that the friction of the cams f, f, on the block g gives an axial
motion to the tube d³, and the under part c¹ of the piston.

page_text: "
This axial motion is communicated to the upper part c of the piston by the screws,
which fix the tube d thereto and pass through corresponding holes in the under
part c¹, the whole upper mass in consequence following the axial motion; is a
friction ring fixed on the axle e (see Figures 2, 6, 7, and 8), and formed with two
swelling parts corresponding with the angle X, which is formed (Figure 1) by the
line of the ends of the cams f, f; with the line from the centre of the axle e to the
point of contact of the cams with the block g.
On the inside of the frame is fixed a lever n, m, o, having its fulcrum at m; at n
is a friction roller, and at o a half ring fitting the outside of the drill bar.
By the rotation of the axle e, e, during the time of contact between the swelling
parts of the friction ring and the friction roller n of the lever n, m, o, the drill
bar will be kept tight, and being thereby unable to follow the axial motion of the
mass caused by the action of the cams f, f, the nut on the top of the tube d will
consequently go back, and so create the feeding.
By means of the slot shown in the ring the screw which fixes the latter to the
axle e can be adjusted so as to lengthen or shorten the surface of friction of the
lever at n, and thereby regulate the extent of feeding given to the drill bar.
⋅
On the axle e may be fixed fly wheels furnished with handles for working the
machine by hand, or pulleys may be used for working by steam or other power.
The eyes or rings q, q, are intended to receive a bar for giving to the machine
any desired inclination, the other end of the bar being fixed on a cross bar of the
frame C.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what is claimed as the Invention is,-
1. The construction and arrangement of piston, substantially as and for the
purpose hereinbefore described and illustrated by the accompanying Drawing.
2. The construction and arrangement of apparatus for feeding the drill, sub-
stantially as hereinbefore described and illustrated by the accompanying Drawing.
In witness whereof, I, the said Edward Thomas Hughes, have hereunto set
my hand and seal, this Twelfth day of Marcb, in the year of our Lord
One thousand eight hundred and eighty.
T T HIGHES
01