Improvements in Apparatus or Machinery for Drilling Rocks and other Hard Substances.
Year: 1890

page_text: Date of Application, 7th Feb., 1890
Complete Specification Left, 7th Nov., 1890-Accepted, 20th Dec. 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus or Machinery for Drilling Rocks and
other Hard Substances.
We, RICHARD STEPHENS and WILLIAM CHARLES STEPHENS, both of Pool, in the
County of Cornwall, Engineers, do hereby declare the nature of this invention to be
as follows:-
:-
Our invention relates to apparatus or machinery for drilling rocks and other hard
substances and it comprises the improvements hereinafter described.
According to our invention the valve for admitting steam to the cylinder is operated
directly from the piston rod by means of a protuberance or enlargement thereon,
instead of indirectly through the medium of a cam or tappet as has frequently hereto-
fore been the case.
The said valve which is preferably in the form of a plate having suitable openings
therein is mounted upon a stud, bolt or pin passing through the valve-chamber and
adapted to oscillate on the said bolt or the like under the action of the protuberance
upon the piston rod, the said openings in the valve, during the movement thereof,
being caused to correspond with suitable inlet and exhaust ports formed in the walls of
the valve-chamber.
The valve is advantageously faced upon both sides, so that, when it becomes worn
upon one side it may be reversed.
In order to provide for the rotation of the piston-rod we employ two clutch-discs,
one of which is secured to the head of the twist-bar and adapted to rotate therewith,
while the other is held against rotation and is normally pressed towards the first
mentioned clutch by means of a spring.
Dated the 7th day of Bahoun 1900
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Apparatus or Machinery for Drilling Rocks and
other Hard Substances.
We, RICHARD STEPHENS and WILLIAM CHARLES STEPHENS, both of Pool, in the
County of Cornwall, Engineers, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and ascer--
tained in and by the following statement
Our invention relates to apparatus or machinery for drilling rocks and other hard
substances, and it comprises the improvements hereinafter described
According to our invention the valve for admitting steam or other motive fluid to
the cylinder is operated directly from the piston rod by means of a protuberance or
enlargement thereon, instead of indirectly through the medium of a cam or tappet as
has frequently heretofore been the case.
The said valve which is in the form of a plate having suitable openings and recesses
therein to form ports is mounted upon a stud, bolt or pin passing through the valve-
chamber, and adapted to oscillate on the said bolt or the like under the action of the
protuberance upon the piston rod, the said ports in the valve, during the movement
thereof, being caused to correspond with suitable inlet and exhaust ports formed in the
walls of the valve-chamber.
The valve is advantageously faced upon both sides, so that, when it becomes worn
upon one side it may be reversed.

page_text: Co provide for the fOCATION OF the piston-rod we employ two cluten-discs,
one of which is secured to the head of the twist-bar and adapted to rotate therewith,
while the other is held against rotation and is normally pressed towards the first
mentioned clutch by means of a spring.
To enable our invention to be fully understood we will describe the same with
reference to the accompanying drawings, in which
1
1
Figure 1 is a longitudinal section of a rock-drill provided with our improvements:
Figures 2 and 3 are transverse sections of the same on the lines a x and y y
respectively:
Figure 4 is a view of the face against which the valve works : and
Figure 5 is a view of the valve:
Figures 6 and 7 are sections of the valve on the lines a¹¹, y¹ y¹ respectively:
Figure 8 is a side view of the clutch-discs for causing rotation of the piston-rod ;
and,
Figure 9 is a face view of one of the said discs.
Similar letters of referenco indicate corresponding parts in the several figures of the
drawings.
a indicates the cradle, and the cylinder adapted to slide in the same and to be
moved by the screw c; d is the piston-rod, and e, e' are the pistons: fis the valve-
chest provided with two pairs of ports 9, 91, h, h', the former of which establish
communication between the interior of the valve-chest and the atmosphere, and the
latter of which communicate by means of passages i, i¹ with two ends of the
cylinder b.
jis our improved valve which is provided with a pair of ports or openings k, k¹
passing entirely through it, and on each side with a pair of recesses 1, 11: the said valve
being carried upon a bolt or pin m passing through the valve-chest and being oscillated
thereon by means of the protuberance n on the piston-rod between the pistons e, e'.
o, o' are the clutch-discs, and p is the twist-bar which, at one eud is provided with an
extension 9 of smaller diameter than the twist-bar proper, the said extension being
supported at its end in a bearing g' in the cylinder cover r.
The clutch disc o is firmly secured to the extension q so as to rotate with the twist-
bar, whilst the clutch-disc o passes freely over the said extension. The said disc o¹ is
held against rotation by means of lugs o2 entering corresponding recesses in the
cylinder cover but is free to slide on the said extension.
s is a spring which normally tends to press the disc o' into engagement with the
disc.o.
The operation of the apparatus herein before described is as follows:-Assume the
pistons to be at their innermost position and the opening to be in coincidence with
the port h¹ communicating with the rear end of the cylinder through the passage i¹:
if now air or steam is admitted into the valve-chest, for instance, through the aperture t,
the air or steam will act upon the piston e¹ and force the same together with the rod d
forward; by the time the forward position is reached the protuberance n, by acting
upon the underside of the valve j, will have oscillated the same sufficiently far to bring
the opening into coincidence with the port h and the recess (adjacent to the
valve face) over the ports g, h, so that the compressed air or steam will then enter
the front end of the cylinder through the passage i and act upon the piston e to force
the same with the rod d' backwards, the air or steam in the rear end of the cylinder
being at the same time forced out through the passage ¹, the port ', the recess and
the port g¹, and so on, the operation being repeated at each stroke of the piston.
During the outstroke of the pistons when the drill is driven, the twist-bar p is caused
to rotate, the teeth of the disc o acting upon the teeth of the disc o', in such a manner,
as to force the latter disc backwards. On the instroke of the pistons, however, during
the withdrawal of the drill the teeth of the two discs being in engagement, the pistons
and piston-rod are caused to rotate upon their axis in a well known manner.
The object of constructing the valvej with two sets of recesses 1, 1 on opposite sides
thereof is that, when tho valve is worn upon one face it can be reversed to work upon
its other face.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. In apparatus or machinery for drilling rocks and other hard substances, the
employment of a valve provided with three sets of ports or passages, namely, one set
of inlet ports passing entirely through the valve, and one set of outlet ports on each
side thereof, substantially as, and for the purpose, described.
2. The combination with the twist-bar of two clutch-discs, one of which is secured
to the bar, whilst the other is secured to a rod sliding within, but incapable of rotation
in, a recess in the piston cover, substantially as, and for the purpose, described.
3. The combination in a rock-drill of a piston, a valve having two sets of ports, one
of which passes through the valve, and the other of which is cut out of the body of the
valve, the said valve being operated by a protuberance upon the piston-rod between
the pistons; and a twist-bar adapted to be held against rotation in one direction by
means of a disc secured thereto, and engaging with a second disc held against rotation,
the said second disc being adapted to slide upon its axis to allow the disc upon the
twist-bar to be rotated during the motion of the piston in the other direction, substan-
tially as described.
Dated the 7th day of November 1890
RICHARD STEPHENS.
WILLIAM CHARLES STEPHENS.
Witness:
M. B. NETTELL,
Ventonraze, Illogan,
Accountant.
G. F. Redfern & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.