IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF THE ROCK DRILL
Year: 1878

page_text: LETTERS PATENT to John Brown, the elder, of No. 13, Rawlinson Street,
Dalton-in-Furness, in the County of Lancaster, Mechanical Engineer, for the
Invention of "IMPROVEMENTS IN THE CONSTRUCTION AND WORKING OF THE
ROCK DRILL."
Sealed the 30th July 1878, and dated the 30th May 1878.
PROVISIONAL SPECIFICATION left by the said John Brown at the Office of
the Commissioners of Patents on the 30th May 1878.
JOHN BROWN, the elder, of No. 13, Rawlinson Street, Dalton-in-Furness, in tho
County of Lancaster, Mechanical Engineer. "IMPROVEMENTS IN THE CONSTRUCTION
AND WORKING OF THE ROCK DRILL"
This Invention has for its object improvements in the construction and working
of the rock drill.
The improvements are shewn in the Drawing hereunto annexed.
In the Drawing, A, B, represents a spring ring around the piston rod, travelling
to and fro with it, and serving as a stuffing box; B, B, are piston rings; C, pistons
and piston rod; D, inlet for admitting compressed air or fluid, by which the drill is
to be worked, to the cylinder between the pistons; E, outlet; F, socket for receiving
drill; G, side grooves at the ends of the piston, for causing them to turn when
acted on by the compressed air; H, india-rubber rings.
When the apparatus is at work compressed air is admitted continuously to the
central portion of the cylinder between the pistons, and passes from thence alter-
nately to the two ends of the cylinder, as the piston moves to and fro, as will be
seen by the longitudinal section of the apparatus, and so keeps the piston in
movement.
The peculiarities of the apparatus consist,-
First. In having the pistons and piston rod in one solid piece (by preference of
cast steel) with side grooves at the ends of the pistons.
Second. In having a spring ring around the piston rod, which works to and fro
along with it, and dispenses with a stuffing box.

page_text: Third. That there are three ports in the cylinder for the admission of compressed
air on the inlet side, and two ports on the outlet or exhaust side, and that the
pistons are driven to and fro, and are also turned by the compressed air acting upon
or in the grooves formed at the ends.
Fourth. That the pistons act as a valve, without any other valve being
necegge
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Brown in the Great Seal Patent Office on the 29th November
1878.
JOHN BROWN, the elder, of No. 13, Rawlinson Street, Dalton-in-Furness, in the
County of Lancaster, Mechanical Engineer. "IMPROVEMENTS IN THE CONSTRUCTION
AND WORKING OF THE ROCK DRILL."
This Invention has for its object improvements in the construction and working
of the rock drill.
I form the piston of a rock drill of a solid piece of cast steel, having grooves
upon three several parts of it, and I cause the compressed air or actuating fluid to
operate in these grooves, to impart rotation to the piston and to the drill or tool
which it carries in both its forward and backward motion, but the compressed air
also acts on the ends of the piston, and imparts forward and backward motions.
I also form ports in the sides of the cylinder, and cause the piston in its move-
ment to and fro over these ports to control the passage of the air or actuating fluid
to and from the capacities within the cylinder, by opening and shutting the ports
on the several parts of the piston. I cause the piston rod to pass in and out of the
neck of the cylinder, which is not packed, but in lieu of packing a spring ring is
carried upon the piston rod.
In order that my Invention may be most fully understood and readily carried
into effect, I will proceed to describe the Drawings hereunto annexed.
Figure 1 is a side elevation partly in section of a rock drill constructed according
to my Invention. This Figure also shows the slide and the supporting bar upon
which the drill is carried.
Figure 2 is an end elevation of the drill, and also shows the slide and sup-
porting bar.
Figure 3 is a longitudinal section of the drill; Figure 4 is a transverse section;
and Figure 5 is a plan partly in section of the same.
a, a, is the supporting bar; it is fixed in position in any convenient manner; and b
is a clip which can be made fast upon the bar a in any position along it; b' is a socket
upon the side of the clip b, and in this socket the stud c¹ is able to turn, but it can

page_text: 111
be locked by means of the locking screw 6". The slide c is carried upon the top of
the stud c¹, and it receives the foot d' formed upon the side of the cylinder d; e is a
screw passing through the foot d¹, and by means of this screw, which has a handle
upon its end, the cylinder and other parts can be moved along the slide c; in this
way the workman feeds the machine forward to its work. f is the piston working
within the cylinder d; the piston is in one piece with its rod f¹, and a socket to
hold the drill or tool is formed at the outer end of the piston rod. fll are spring
rings upon the piston, which render the fit of the piston within the cylinder air-tight
at the places where the rings occur; fill are notches cut in the piston, both in the
middle and near its ends; they form teeth, upon which the compressed air or fluid
acts as it passes through the cylinder to effect the rotation of the piston with its
rod and tool. G is the entrance for the air or actuating fluid; the passage is so
directed that the air or fluid enters the cylinder nearly in a tangential direction,
and strikes the teeth or sides of the grooves in the central portion of the piston;
the air or fluid finds itself in the central space of the cylinder, between the packing
rings at the two ends of the piston. In Figure 3 the piston is shown at mid-
stroke, but this is not a position in which the drill when at work would come to
rest, but the piston travelling on uncovers one or other of the two admission
ports d*, d*, and allows air or fluid to pass from the central space to the end of the
cylinder, where, acting upon the piston, it drives it towards the other end of
the cylinder. The compressed air or fluid in thus entering the end space of the
cylinder acts a second time in the grooves formed in the piston, and the entrance
passage being suitably formed, as is seen in Figure 4, a second rotary impulse is given
to the piston. The piston in its course first closes the port d* by which the. air or
fluid which is urging it forward entered, and immediately afterwards it uncovers
the corresponding exit port d**, and so the pressure behind the piston is relieved.
During this time, at the other or further end of the cylinder, the piston first closes
the other exit port d**, and immediately afterwards uncovers the other entrance
port d, thus admitting air or fluid to the cylinder and to again drive back the
piston. The machine is so adjusted to its work that the blow is struck with the
tool in the outward or effective stroke just as the admission of air to carry back
the piston takes place. In the return stroke the piston is brought to rest by the
resistance of the compressed air or actuating fluid admitted behind it. fxx is a
spring ring upon the part of the piston rod, which works within the neck on the
cylinder end to form an air-tight joint.
Having thus described the nature of my said Invention, and the manner of per-
forming the same, I would have it understood that I claim,-
First. The means by which the air or actuating fluid is caused to impart rotary
motion to the piston and the tool which the piston carries, substantially as
described.
J
Second. The means by which the piston is made to control the admission of the
air or actuating fluid to and its exit from the cylinder, substantially as described.
Third. The means by which the use of packing is avoided in the neck, by which
the piston rod passes out of the cylinder by the application of a spring ring to the
rod, substantially as described.
Fourth. The construction of rock drills, substantially as described and represented
in the annexed Drawings.
In witness whereof, I, the said John Brown, have hereunto set my hand and
seal, this Eighteenth day of November, in the year of our Lord One thousand
J. BROWN. (LS.)