Improvements in Rock Drills, Direct Acting Engines, and the like.
Year: 1897

page_text: Date of Application, 17th Aug., 1897-Accepted, 2nd Oct.,
1897
COMPLETE SPECIFICATION.
Improvements in Rock Drills, Direct Acting Engines, and the like.
We, HENRY RICHARD HANCOCK of Moonta Mines in the Province of South
Australia. Mine Superintendent, HENRY LIPSON HANCOCK and LEIGH GEORGE
HANCOCK of the same address Mining Engineers, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:―
Our invention relates to certain improvements in direct acting machines driven
by air or steam pressure. For convenience we propose to describe it with reference
to rock drills driven by compressed air, to which it is intended more particularly
to refer, but it may also be applied to any direct acting machines, such as pumps
driven by steam.
With the drills and other like machines at present in use, considerable difficulty
is experienced in preventing leakage of the compressed air. Owing also to the
multiplicity of the parts employed in the construction of the drill, a further
considerable amount of power is lost by friction, and when the cylinder becomes
worn, the machine can only be repaired by providing a new cylinder.
The objects of our invention are to lessen this leakage of the compressed air, to
utilise as fully as possible the power supplied to the machine by simplifying the
number of parts, and by a special construction of the cylinder to permit of the
worn parts being renewed without the necessity of a new cylinder.
We accomplish this purpose by constructing the drill or other machine with-
(a) a new and improved inlet valve (b) by an improved contrivance attached to the
valve whereby it is automatically opened and closed by the action of the drill
piston, (e) by a general simplification of the parts which we are enabled to effect
by means of our improved inlet valve, and (d) by providing the cylinder with a
removable liner which can be readily replaced when it becomes worn.
In the accompanying drawings illustrating our invention-
Fig. I is a plan of the drilling machine complete.
Fig. II. elevation of the machine shewing the exhaust openings covered with
stoppers.
Fig. III. a longitudinal section shewing the internal parts of the machine, but
without the internal liner to the cylinder.
Fig. IV. horizontal section of the cylinder along the lines d-d in Fig. II,
shewing air ports and slot hole for the valve spindle, also the position of the
exhausts.
Fig. V. cross section through the parts marked a-a in Fig. I, shewing valve
spindle in position, and air ports.
Fig. VI. cross section through b-6 (Fig. I) shewing the air port admitting air
to the piston chamber.
Fig. VII. longitudinal section along a line cc (Fig. I) shewing the valve in
section, and piston and valve spindle actuated by the same, together with the
action of the piston of the valve spindle at the end of the in-stroke.
Fig. VIII. longitudinal section of the same shewing the action of the piston of
the valve and valve spindle at the end of the out-stroke.

page_text: Fig. IX. details of the valve, the valve spindle being removed in order to shew
the ports more clearly.
Fig. X. longitudinal section of the cylinder of the machine with removable liner
inserted.
Fig. XI. cross section along a line e-e in Fig. X, shewing the slot hole for the
valve spindle and the cylinder with inner lining.
:
Fig. XII. plan of the removable cylinder liner, shewing the slot hole for the
valve spindle and openings at each end leading from the air ports.
Figs. XIII & XIV. elevations of the front and rear ends of the removable
cylinder liner, shewing the position of the ports.
Fig. XV. end elevation of rifle bar, ratchet wheel and pawls for holding the bar
in position during the back stroke of the piston.
Similar letters of reference refer to similar parts in all the figures.
Our improved rock drill is mounted upon a bed plate or cradle along which the
machine is caused to travel forward by the usual screw device, as shewn more
particularly in Figs. I and II. It is provided with certain appliances and connec-
tions common to such machines, but which as they form no part of our invention
we do not describe.
Referring to the accompanying drawings in which the several parts forming
our invention are shewn in detail:-
.
A is the main body of the machine, having an internal cylinder B in which
works a piston C as more particularly described later. The cylinder B is provided
with two exhaust openings B1, B2 (Figs. III and X). At either end of the
cylinder B are air ports D, D' (Figs. III and X) leading from the cylinder B to the
inlet valve chamber A2 formed in the body of the machine at A¹. The inlet valve
chamber A (Figs. X and XI) is cylindrical and is provided at either end with
suitable removable caps A6
fastened to A¹. The inlet valve E has a
rocking motion causing it to partially rotate in the inlet valve chamber Aª
permitting the air to enter from the valve first into one and then the other of the
ports D, D. The details of the construction of the valve E which consists of an
open ended tubular piece are shewn more particularly in Figure IX. The com-
pressed air from the air compressor is introduced into the interior of valve E
through a channel A3 formed in the side of the casing A¹. A similar channel A*
closed with a cap A6 is provided at the opposite end of the valve chamber A² so
that the compressed air can be introduced from either side. The head of the
machine at A' is provided with a circular opening closed by a removable cap A
in order to permit access to the interior of the valve E and to the valve spindle F
through a circular opening E. The compressed air passing into the interior of
the valve E through either of the channels A3 or A flows through one or other
of the openings E³, E3 formed in the lower portion of the valve into one or
other of the ports D, DI, with which the openings E2, E3 correspond. In order
to automatically impart a rocking motion to the valve E causing it to partially
rotate so as to bring alternately the opening 2 opposite the port D and the
opening E3 opposite the port D₁ and to admit the compressed air alternately to
one or the other, the valve E is brought in communication with the piston C by
valve spindle F. This valve spindle is tightly fastened to the valve E by having
a screw thread formed upon it (Figs. VII and VIII) and by being tightly screwed
into an opening E having an internal screw thread provided for the purpose in
the lower part of the valve E. A washer and screw head to the valve spindle
prevents any leakage of the air. The valve spindle F projects downwards into the
cylinder B through a slot A5 provided for the purpose in the body of the machine A
as shewn more particularly in Figs. V. VII. VIII. and XI., and is actuated by the
movement of the piston C. The piston C is provided with spring rings in the
ordinary way formed in the heads C1, C2, the body of the piston C between
the heads C, C being recessed in order to allow room for the valve spindle F. The
compressed air entering the valve E as before described through either of the
channels A³, A flows through the valve openings Es (if that is then open) through
a

page_text: the port D into the rear end of the cylinder B driving forward the niston C until
the head C¹ has passed the exhaust B₁, from which the air then escapes. At the
sanie time the piston head C pressing against the valve spindle F causes the
valve E to partially rotate, shutting the port D and opening the port D¹ by
bringing the valve opening E3 opposite to it. The compressed air then flows in
the front end of the cylinder B and by its pressure upon the head C drives the
piston back until the exhaust B2 has been opened allowing the air to again escape.
Meanwhile the head C2 similarly engaging the valve spindle F again causes the
valve to partially rotate, closing the port I) and again opening the port D, and so
on alternately driving the piston backwards and forwards. To the piston C is
attached the piston rod to which the drill is fixed.
We find in practice that in order to secure good despatch with the return stroke
of the piston C and to economise air, 1 inches is a very suitable diameter for the
piston rod, but do not bind ourselves to any dimensions.
The head of the piston C is constructed with internal rifling corresponding
with similar grooves formed in the rifle bar H (Fig. III) by means of which a
rotatory motion is imparted to the drill on the back stroke in the usual manner.
Upon the head of the rifle bar H is fixed a ratchet H¹ provided with pawls H³
for folding the ratchet in position during the back stroke of the piston G whilst
allowing it to slide forward during the forward stroke of the piston C. This
however, is of usual construction for such purpose, and forms no part of our
invention.
In practice, owing to the action of the piston heads C, C the interior of
cylinder B becomes worn allowing the air to leak past the piston heads, and thus
causing loss of power and interferring with the efficiency of the drill. In the drills
at present in use the whole cylinder when worn has to be replaced. To obviate
this we on occasion construct the cylinder of our improved drill with a removable
internal lining I as shewn more particularly in Figs. X, XI, XII, XIII and XIV.
This removable lining I is provided with an opening I¹ through which the valve
spindle passes, with holes corresponding with the exhaust B1, B2 and with
openings 12, 13 corresponding with the outlet ends of the ports D, D¹. As the
internal face of the lining I becomes worn by the action of the cylinder heads, a
fresh lining can be easily fixed in its place, and the efficiency of the drill thoroughly
restored at small expense.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is
1. In rock drills and other like direct acting machines, a cylindrical valve,
substantially as herein described.
2. In rock drills and other like direct acting machines, a cylindrical valve
to which a rocking motion causing it to partially rotate is imparted by the action
of the piston, substantially as herein described.
3. In rock drills and other like direct acting machines, the combination with a
cylindrical valve of a valve spindle, acted upon by the machine piston, substantially
as herein described.
4. In rock drills and other like direct acting machines a cylindrical valve
into which the compressed air or steam is conducted, and through which it flows
alternately through one or other of the openings at the base, into a port leading
to each end of the cylinder, substantially as herein described.
5. In rock drills and other like direct acting machines, the combination with a
cylindrical valve, of a valve chamber formed in the body of the machine, and
provided with caps in such manner that the pressure of the air or steam is applied
internally only to the valve, substantially as herein described.
6. In rock drills and other like direct acting machines, the combination with a
cylindrical valve operated by a valve spindle, of a slot, for the same leading into
the cylinder of the machine, substantially as herein described.

page_text: 7. In rock drills and other like direct acting machines, the combination with a
cylindrical valve, having openings at the base corresponding with air ports leading
to either end of the cylinder, of a cylinder having exhaust openings, through which
the air or steam escapes at either end of the stroke of the piston, substantially as
herein described.
8. In rock drills and other like direct acting machines, the combination with a
cylindrical valve operated by a valve spindle projecting into the cylinder, of a
piston provided with heads actuating the valve spindle, and recessed so as to allow
space for the valve spindle, substantially as herein described.
9. In rock drills and other like direct acting machines, providing the piston
cylinder with a removable lining substantially as herein described.
10. In rock drills and other like direct acting machines, providing the piston
cylinder with a removable cylindrical lining, having openings corresponding with
the exhaust openings of the cylinder, and a slot for the valve spindle, together
with openings corresponding with the air ports substantially as herein described,
and shewn at Figures X. XI. XIII and XIV.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.