IMPROVEMENTS IN ROCK DRILLS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER DRILLING APPARATUS
Year: 1877

page_text: "
LETTERS PATENT to Philip John le Gros, of 4, Queen Street Place, London,
Engineer, for the Invention of IMPROVEMENTS IN ROCK DRILLS, PART OF
WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER DRILLING APPARATUS."
PROVISIONAL SPECIFICATION left by the said Philip John le Gros at
the Office of the Commissioners of Patents on the 30th August 1877.
PHILIP JOHN LE GROS, of 4, Queen Street Place, London, Engineer. "Iм-
PROVEMENTS IN ROCK DRILLS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE
TO OTHER DRILLING APPARATUS."
These improvements consist,―
Firstly. In new arrangements for operating the valve motion and the feeding device
which regulates the advance of the cylinder towards the rock.
Secondly. In the arrangement of the rotary and feed ratchets and pawls, these
being also applicable to ratchet braces used for drilling.
Thirdly. In the chuck or clamp for holding the bit in the piston rod.
And, Fourthly. In improvements in the mode of fixing the machine.
In the first improvements, the mode of operating the valve motion and the feeding
device which regulates the advance of the cylinder towards the rock, in one case
consists of a single double-ended lever actuated by the piston and brought back to
its intermediate position by one or more springs, or two small pistons acting either
on a projection or cam made on the lever shaft, or acting directly on the lever itself;
the distribution of the steam or compressed air being made by using either one or
two pistons working inside cylinders, or one or two slide valves working on faces
receiving the steam either from their outside or from their inside. This valve or
valves, or piston or pistons being placed either near the middle of the main cylinder
and sending steam through the side ports to the respective ends of the main cylinder,
or at each end of the main cylinder directly over the opening where the steam is to
be supplied to the cylinders, so as to dispense with the side ports. The valve may

page_text: also be a sliding sleeve or pipe carrying a lug actuated by the piston, and moving
with it during part of its travel, such sleeve or pipe during the motion of the piston
covering and uncovering ports communicating with the inside of the main cylinder,
and thus giving the distribution.
The motion of the double-ended lever is regulated by the shape of the groove in
the piston, so as to be used also to actuate the feeding device, either by using a cam
placed on the end of a lever shaft and working a series of levers or cranks, so made
as to vary the rapidity of the feed; or directly by using the motion of the slide
valve rod touching a tappet or cam at the proper noment when feed is required,
this tappet actuating the feeding pawl and ratchet through a lever or levers.
Where the sliding sleeve is used, the travel of the sleeve gives the motion for the
feeding device at the proper point for the stroke either by means of a peculiar groove
or rim, or by another lug or cam on the sleeve actuating a rocking shaft transmitting
the motion to the feed ratchet and pawl. Or the feed may in either case be obtained
by boring a hole down through the centre of the rifle bar through which to pass a
small shaft with a bulb at the end of it. The piston carries a bar or diaphragm
through the centre of which the rod passes, and as the piston descends, the bar
or diaphragm strikes against the bulb, and gives the motion to the feed.
The motion of the piston is guided by a twisted or rifle bar passing inside a
nut, so made as not to reduce the effective area of the piston, such bar being
twisted in case of a rotary motion, or straight in case the piston should be used
without any rotary motion.
In the second improvement, the arrangement of the rotary and feed ratchets and
pawls, I apply to rock drilling machinery the principle of friction wheels for the
arrangement of ratchets and pawls used for the rotary and feed motions, the
ratchet being a cylinder in which one or several grooves are cut, and the pawl being
part of another cylinder, wedge shaped, with increasing section fitting these grooves
and turning round an axis so placed as to release all friction when the ratchet turns
in one direction, and to increase it as soon as the direction of motion is reversed,
the same arrangement being also applicable to the ordinary ratchet brace replacing
the spring, pawl, and ratchet.
The third improvement in the chuck or clamp for holding the bit in the piston
rod is by using a collar (protecting the bottom end of the piston rod from any injury
arising from blows) carrying screws acting on a steel piece holding the bits in its
place.
The fourth improvement in the mode of fixing the machine is by using a hinged
collar carrying a cup receiving the drill, and so made as to be slackened or made
tight to the column or stand by screwing up the sides opposite to the hinge, and
without touching the bolt holding the rock drill, and made to slide on a column so
as to approach as close as possible to the face to be worked.
The tripod is made so that each leg may be moved separately as well as the
cup. To effect this, the side legs enter each side of the cup, and hold the cup
in its place by the friction obtained by screws tapped in the cup. The back
leg is made fast to the side legs by the friction caused by the screwing of two
nuts working on a cylindrical projection of the side legs without interfering with
the screws holding the cup.
Although in the description given, steam only has been mentioned, compressed
air will be equally applicable.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Philip John le Gros in the Great Seal Patent Office on the 28th
February 1878.
PHILIP JOHN LE GROS, of 4, Queen Street Place, London, Engineer. " IMPROVE-
MENTS IN ROCK DRILLS, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO OTHER
DRILLING APPARATUS."
Figure 1 is a longitudinal section of the rock drill with part of my improvements,
the piston rod being partly broken away.
Figure 2 is a back view, partly in section, of the same drill.
Figure 3, a side view of the above, also partly in section, all three Figures relatively
on the line A, B.
Figure 4, cross section of Figure 1 on line A, B.
Figure 5, plan of rock drill as above.
Figure 6, view of friction wheels with pawls in section.
Figure 7, section through drill clip.
Figure 8, section shewing the sliding sleeve.
Figure 9, front view and part section of tripod with front legs broken off.
Figure 10, back view of tripod with back leg broken off.
Figure 11, side view of tripod with cup in section, legs broken off.
Figure 12, end view of nut and bolt of tripod.
Figure 13, plan and sections shewing bevil of the pawls.
The like letters in each figure representing like parts in all the Figures.
These improvements consist,-
Firstly. In new arrangements for operating the valve motion and the feeding
device which regulates the advance of the cylinder towards the rock.
Secondly. In the arrangement of the rotary and feed ratchets and pawls, these
being also applicable to ratchet braces used for drilling.
Thirdly. In the chuck or clamp for holding the bit in the piston rod.
And, Fourthily. In improvements in the mode of fixing the machine.
In the first improvements, the mode of operating the valve motion and the feeding
device which regulates the advance of the cylinder towards the rock, in one case
consists of a single double-ended lever a, shewn in Figures 1, 2, 3, 4, actuated by the
piston b, and brought back to its intermediate position by one or more springs c (or
two small pistons in other cases) acting either on a projection or cam a' made on the
lever shaft or acting directly on the lever itself. The distribution of the steam or com-
pressed air being made by using either one or two pistons & working inside cylinders
(or one or two slide valves working on faces receiving the stean either from their
outside or from their inside. This valve or valves or piston or pistons being placed
either near the middle of the main cylinder and sending steam through side ports to
the respective ends of the main cylinder or at each end of the main cylinder directly
over the opening where the steam is to be supplied to the cylinders, so as to dispense
with the side ports), the valve may also be a sliding sleeve or pipe e, see Figure 8,
carrying a lug e actuated by the piston and moving with it during part of its travel,
such sleeve or pipe during the motion of the piston covering and uncovering ports f
communicating with the inside of the main cylinder, and thus giving the
distribution.
The motion of the double-ended lever is regulated by the shape of the
groove in
the piston, so as to be used also to actuate the feeding device, either by using a cam
placed on the end of the lever shaft, and working a series of levers or cranks so
made as to vary the rapidity of the feed; or directly by using the motion of the
side valve rod a touching a tappet or cam g at the proper moment when the feed is
required, this tappet actuating the feeding pawl and ratchet through a lever h, or
levers, see Figures 1, 2, 3, and 5; the lever h being keyed on or forming part of the
tappet g, is actuated by the rod d', striking tappet g; this acting through the

page_text: sliding piece i operates the pawl and ratchet which feeds the drill towards the rock,
as the drill penetrates the rock.
Where the sliding sleeve is used, see Figure 8, the travel of the sleeve gives the
motion for the feeding device at the proper point of the stroke, either by means of a
peculiar groove j (or rib, or by another lug or cam on the sleeve, not shewn, being
modifications of the plan) actuating a rocking shaft k with fulcrum ¹ having a
pin sliding in the groove j, transmitting the motion to the feed pawl and ratchet.
The motion of the piston is guided by a twisted or rifle bar m passing inside a
nut n, so made as not to reduce the effect of area of the piston, such bar being
twisted in case of a rotary motion, or straight in case the piston should be used
without any rotary motion.
The twisted bar and the nut are in common use in rock drills, but my improve-
ment consists in perforating the nut n by means of the passages o; by which means,
in place of having the effective area of the piston diminished by the area of the rifle
bar, I obtain the full effective area of the piston for the pressure of steam, inasmuch
as the steam passing through the nut n by the passages o acts below the end of
the rifle bar, and the area of the rifle bar does not thus diminish the effective area
of the piston.
In the second improvement the arrangement of the rotary and feed ratchets and
pawls I apply to rock drilling machinery the principle of friction wheels in place of
the arrangement of ratchets and pawls used for the rotary and feed motions, the
ratchet being replaced by a cylinder in which one or several grooves are cut, and
the pawl being replaced by a part of another cylinder, wedge shaped, with increasing
section, see Figures 6 and 13, fitting these grooves and turning round an axis so
placed as to release all friction when the wheel turns in one direction, and to increase
it as soon as the direction of the motion is reversed, the same arrangement being
also applicable to the ordinary ratchet brace replacing the spring pawl and ratchet.
In Figures 6 and 13, is the part cylinder or pawl; q, the cylinder or ratchet,
the increasing section being particularly shewn, Figure 13, p¹, p².
The third improvement in the chuck or clamp for holding the bit in the piston
rod is by using a collar (protecting the bottom end of the piston rod from any injury
arising from blows) carrying screws acting on a steel piece holding the bit in its
place, as shewn in Figures 1, 3, and 7.
The fourth improvement is the tripod, made so that each leg may be moved
separately as well as the cup. To effect this the side legs enter each side of the cup
and hold the cup in its place by the friction obtained by screws tapped in the cup.
The back leg is made fast to the side legs by the friction caused by the screwing
of two nuts working on a cylindrical projection of the side legs, without inter-
fering with the screws holding the cup, as shewn in Figures 9, 10, and 11.
Although in the description given steam only has been mentioned, compressed
air will be equally applicable.
Having now described and particularly set forth the nature of the said Invention,
and the manner of carrying the same into effect, I would have it understood
what I claim is,-
Under the first improvements, the particular arrangement of the double-ended
lever, acting as shewn for the distribution of the steam, and the feeding the drill
to the rock from the valve rod, substantially as described.
Also under the same described improvements, the sliding sleeve and the arrange-
ment described for the purpose set forth, substantially as described; also under
the same improvements the perforated nut through which the twisted or straight
bar passes, as shewn in Figures 1 and 4, for the purpose set forth, substantially
as described.
Under the second improvements, the friction wheel and portion of friction wheel
in substitution for ratchets and pawls in rock drills, as well as for other purpose,
where applicable to other drills, substantially as described.
Under the third improvements, the means of holding the drill bit, and protecting
the end of the piston rod, substantially as described.

page_text: Under the fourth improvements, the particular arrangement and method of fixing
and adjusting the tripod, substantially as described.
In witness whereof, I, the said Philip John le Gros, have hereunto set my
hand and seal, this Twenty-eighth day of February, in the year of our Lord
One thousand eight hundred and seventy-eight.
PHILIP J. LE GROS. (L.S.)