Improvements in and relating to Kock Drills.
Year: 1898

page_text: Date of Application, 13th July, 1898-Accepted, 13th Aug., 1898
Improvements in and relating to Kock Drills.
I, JAMES MCCULLOCH, of Portreath, in the County of Cornwall, Engineer, do
hereby declare the nature of this invention, and in what manner the same is u
be performed, to be particularly described and ascertained in and by the follow-
ing statement: —
This invention relates to rock drills and has reference more particularly to a
convenient and reliable arrangement of valve for distributing the motive fluid to
the cylinder of the drill.
According to the said invention the distributing valve, which may have a rock-
ing motion, is actuated by a wing or vane working fluid-tight in a suitable
chamber. The arrangement is such that as the piston of the drill travels to and
fro, it covers and uncovers suitable subsidiary ports and passages in the drill
casing, thereby admitting motive fluid alternately to opposite sides of the wing
or vane and so causing the latter to swing from side to side and operate the valve
at the proper times.
In order that the invention may be clearly understood and readily carried into
effect I will proceed to describe the same more fully by aid of the accompanying
drawings in which:
Figure 1 is a plan of the salient portion of my improved rock drill.
Figures 2 and 3 are elevations of the same from opposite sides.
Figures 4 and 5 are respectively longitudinal and transverse sections through
the centre of the valve.
Figure 6 is a vertical section on the line
of Figure 4, and
Figure 7 is a section on the line y y of Figure 5.
a is the distributing valve which in the present instance is of cylindrical form
and is provided with grooves al for the reception of packing to render the valve
steam tight whilst at the same time allowing it to turn or rock freely on its axis.
a² is the wing or vane whereby the rocking movement is imparted to the valve.
This wing or vane works fluid tight, after the manner of a piston, in a recess or
cavity a³ in the wall of the valve chest a³, and is operated by motive fluid, the
admission and exhaust of which is controlled by the drill piston in a manner
which will be hereinafter described. The valve is shorter than the valve chest at
and a space or chamber as is left at one end. The opposite end of the valve is
provided outside the valve chest with a ring or collar a having a projection a²
which serves as a handle or trigger to enable the valve to be operated when
necessary independently of the motive fluid as for instance in starting the drill
or when (as sometimes happens in the case of all drills when the rock contains
slides or fissures) the bit sticks or fitchers" "in the hole.
«
6 (Figure 1) is the exhaust pipe or bend into which the space a opens. The
said pipe has a flange which is interposed between the valve chest and a loose
ring or collar 62. Suitable tightening nuts on bolts or studs 64 projecting

page_text: from the said valve chest enable the flange to be clamped tightly up against the
said valve chest in any direction to which the operator may require or wish to
turn the exhaust. The exhaust from the cavity a³ and from the drill cylinder
is concentrated into the pipe b or bend thus having one exhaust to the atmosphere
in any direction desired.
⋅
e is the supply pipe for the steam, compressed air or other motive fluid. This
pipe terminates in a pair of inlet ports c¹ in the valve chest cover.
dd are the exhaust ports of the valve and e is the inlet port thereof which is
situated midway between the said exhaust ports and extends diametrically across
the valve, whereas the exhaust ports open only on that face of the valve next the
cylinder, their other ends opening into the exhaust chamber a³.
The aforesaid arrangement of passages serves when the valve is operated to open
a pair of passages f, f leading to opposite ends of the drill cylinder f*, alternately
to pressure and exhaust.
and e¹ are the subsidiary passages which serve for the fluid operating the
wing or vane a². These passages extend from the inner wall of the drill cylinder
to the cavity a³ in which the wing or vane works and open into the said cavity
on opposite sides of the vanes.
The ends of the subsidiary passages which open into the cylinder are so
arranged that the piston in its travel uncovers one of them at the end of its for-
ward stroke and the other at the end of its backward stroke.
f is an exhaust passage leading from the exhaust chamber as to the cylinder.
The end of this passage is situated midway between the passages and e¹ and
the piston is so constructed that it puts one of the latter into communication with
the said passage f¹ at the same tinie that it opens the other to the interior of the
cylinder.
For this purpose the piston is constructed in the following manner, that is to
say it comprises four rings g, g¹, g², g³, so arranged that one pair is situated at
one end and the other pair at the opposite end of the piston. Between each pair
of rings is an annular groove or recess g* for the ordinary packing rings of the
piston.
The portion g of the piston between the rings g¹g is of reduced diameter and
the space around it is kept constantly open to exhaust by means of the
passage f, but is brought alternately into communication with the aforesaid
passages and el. By this construction the piston not only performs its main
function in operating the drill, but it also serves as a valve to control the flow of
fluid to and from the cavity a³.
Thus when the piston is operating, the spaces on each side of the wing or
vane a² receive motive fluid from the cylinder and are opened to exhaust alter-
nately, so that the wing or vane is caused to swing from side to side of the
chamber thus reversing the valve after each stroke of the piston.
Obviously in some cases I may employ a tapered valve instead of a plain cylin-
drical valve, or I may arrange the valve in any desired position relatively to the
cylinder, instead of transversely thereto as in the example shown in the drawings.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. A drill having its distributing valve arranged to be operated with a rocking
motion by a wing or vane acted on by motive fluid from the working cylinder,
substantially as described.
2. The combination with a valve of the kind referred to in the previous claim,
of a piston which serves both to operate the drill and also as a valve to control
the flow of motive fluid to and from the wing or vane, in such manner that the
exhaust from the cavity in which the wing works, and the exhaust from the
cylinder are led into one main exhaust passage substantially as described and for
the purpose specified,

page_text: 3. A rock drill having its distributing valve and piston constructed and operat-
ing substantially as hereinbefore described with reference to the annexed
drawings.
Dated this 13th day of July 1898
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.