Improvements in and connected with Valves for Fercussive Rock Drills, Direct Acting Pumps, and Engines.
Year: 1890

page_text: Date of Application, 18th July, 1890
Complete Specification Left, 15th Apr., 1891-Accepted, 18th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in and connected with Valves for Fercussive Rock
Drills, Direct Acting Pumps, and Engines.
We, ALBERT WILLIAMS DAW and ZACHARIAS WILLIAMS Daw, both of
Laurvig, in the Kingdom of Norway, Mining Engineers, do hereby declare the
nature of this invention to be as follows:-
The present invention relates to further improvements in the piston valves for
percussive rock drills, direct acting pumps and engines, described in the
Specification accompanying our prior application for Patent No. 8873 dated
9th June 1890, the object being to render the action of such valves more certain
and efficient.
The present invention consists in the employment of two other passages, one in
each of the valve piston cylinders, and permanently open to exhaust, such passages
being used either in addition to the four passages leading to the main cylinder (as
described in the Specification of our prior application above referred to) or in
place of those which lead from the rear of each valve piston cylinder to the
opposite end of the main cylinder.
In addition to the valve pistons for controlling the passages leading from the
cylinders in which such pistons work to the main cylinder, two additional pistons
of larger diameter are provided and form one with the valve pistons, and it is
between these supplemental pistons that the slide valve for controlling the supply
and exhaust of the main cylinder is carried. An annular groove is formed
between each of the supplemental pistons and of the valve pistons, and each of
the former works in conjunction with a cylinder opening into the valve chest, but
which when its piston enters same is cut off therefrom, in which case the annular
groove and the additional port or passage place the rear of the piston directly
open to exhaust, while when the piston has left its cylinder the live air or steam
from the valve chest acts upon the rear of such piston and forces the other
supplemental piston into its cylinder and firmly against the end thereof, such
cylinder being then directly open to exhaust through its additional passage and
the annular groove above referred to.
Before the supplemental piston leaves its cylinder the additional passage has
been previously closed by the valve piston, so that the live air or steam cannot
pass from the valve chest to the additional passage which is open to exhaust.
When the supplemental piston has left its cylinder, the annular groove in the
valve piston and which communicates by a passage formed in the valve piston with
the rear end of the cylinder in which it works (as described in the Specification of
our prior application), is brought over the additional port or passage, so that
the rear of the valve piston is thus put open to exhaust through such additional
passage.
Dated this 18th day of July 1890.
ALLISON BROS.,
Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in and connected with Valves for Percussive Rock
Drills, Direct Acting Pumps, and Engines.
We, ALBERT WILLIAMS Daw and ZACHARIAS WILLIAMS DAW, both of
Laurvig, in the Kingdom of Norway, 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 further improvements in the piston valves for percussive
rock drills, direct acting pumps and engines, described in the Specification
accompanying our prior application for Patent No. 8873 dated 9th June 1890, the
object being to render the action of such valves more certain and efficient.
Our improvements as applied to a percussive rock drill are illustrated in the
accompanying drawings, in which
Fig. is a longitudinal section of a rock drill embodying our improvements.
Fig. 2 is a plan view thereof with the valve chest removed.
Fig. 3 is a plan view of the valve chest.
Fig. 4 is a transverse section on the line A, B, Fig. 1.
Fig. 5 is a transverse section on the line C, D, Fig. 1.
Fig. 6 is a longitudinal section of a rock drill showing a slight modification of
our invention.
Fig. 7 is a plan view of Fig. 6 with the valve chest removed.
Fig. 8 is a longitudinal section of a rock drill showing the application of our
invention to a rock drill in which a piston form of valve is employed.
Fig. 9 is a plan view of Fig. 8 with the valve chest removed.
Fig. 10 is a plan view of the valve chest shown in Fig. 8.
Fig. 11 is a transverse section on line E, F, Fig. 8, and
Fig. 12 is a transverse section on line G, H, Fig. 8.
Like letters indicate corresponding parts throughout the drawings.
The present invention consists in the employment of two passages Q, Q, one in
each of the valve piston cylinders C, C, and permanently open to exhaust, such
passages being used either in addition to the four passages D, A., H, I, leading to
the main cylinder C (as described in the Specification of our prior application
above referred to), or in place of the passages D and I, whether such passages
lead from the rear of each valve piston cylinder to the opposite end of the main
cylinder, or to the same end thereof.
:
In addition to the valve pistons P1, P2, for controlling the passages leading from
the valve piston cylinders C1, C2, in which said pistons P1, P2, work, to the main
cylinder, we construct two additional pistons M and N, of larger diameter, which
pistons from one with the valve pistons P and P, and it is between these
supplemental pistons M and N, that the valve V, for controlling the supply and
exhaust to and from the main cylinder C, is carried. Annular grooves O, O, are
formed between each of the supplemental pistons M and N, and the valve
pistons and P respectively, and each of the pistons M and N works in con-
junction with one of two auxiliary cylinders Y and Z opening into the valve
chest, but when one of the pistons M or N enters its cylinder, such cylinder is cut
off therefrom, and the annular grooves 0, 0, and the additional ports or
passages QQ, provided in the valve piston cylinders, and which are permanently
open to exhaust, place the rear of such supplemental piston directly open to
exhaust, while when the piston has left its cylinder, the live air or steam in the
valve chest acts upon the rear of such piston and forces the other supplemental
piston into its cylinder, and firmly against the end thereof, and thus prevents all
movement or Huttering of the valve pistons and valve, such supplemental cylinder
being then directly to exhaust through its additional passage Q¹ or Q, and
the annular groove
Open
or O above referred to.

page_text: Before the supplemental piston leaves its cylinder the additional passage Q' or Q
has been previously closed by the valve piston P or P, so that the live air or
steam cannot pass from the valve chest to the additional passage which is open to
exhaust.
Further, when either of the supplemental pistons M or N, has left its cylinder Y
or Z, the annular grooves For G formed in the valve pistons 1", 1, and which
said annular grooves F, G, communicate respectively by passages B and B formed
in the said valve pistons P, P, with the rear end of the cylinders C1, C2, in which
such valve pistons P1, P2 work, (as fully described in the Specification of our prior
application for Patent above referred to) are brought alternately over the
additional ports or passages Q', Q, so that the rear of the valve pistons P¹ and P²,
are thus put open to exhaust through such additional passages.
Referring to Figs. 1 to 5 inclusive, it will be seen that the action is as
follows:
--
The piston having arrived at its full backward stroke, air or steam is admitted
from the main cylinder C, through passage H, annular groove G, and passage B,
to the rear of valve piston P and causes the forward movement of the
pistons PN, M, P. In its travel piston P' covers passage and uncovers
passage 1, connecting the lower end of main cylinder Cand valve cylinder C³,
thus maintaining full pressure of air or steam in the valve cylinder C³; then
supplemental piston N emerges from its cylinder Z, and piston M. enters its
cylinder, whilst annular groove is brought into communication with
passage Q, which passage is always open to exhaust, and the complete exhaust of
auxiliary cylinder Y ensured through it and the said annular groove O¹. Now, as
the rear side of supplemental piston M is open to exhaust and the rear side of
supplemental piston N exposed to the live air or steam in the valve chest, the
valve pistons and valve are impelled forward by the pressure on piston N, until
piston M is forced against the end face of cylinder Y, where it is firmly held by
the pressure of live air or steam in the valve chest against the rear of piston N.
During this movement the valve cylinder C' was at first freely open to exhaust
through passage D, port K and exhaust E, and also through passage Qin the
valve chest, until these passages were shut off by the travel of the piston then
annular groove F opens to passage A and communication with the main cylinder C
and exhaust E thus kept, for at the same time the movement of the valve V, will
have put the space below the piston P open to exhaust through passages J and E.
When annular groove Freaches passage A, valve cylinders C and C¹ are both
open to the same (the lower) end of the main cylinder C, the former through
passage I, and the latter through passage B', annular groove F, and passage A,
whereby the pressures on the rear of the valve pistons P2 and P are brought into
equilibrium, when the remaining travel of the valve is effected by the pressure on
the rear of supplemental piston N, as above described. Before supplemental
piston N left auxiliary cylinder Z, the exhaust port Q was closed by the valve
piston P, so that live air or steam cannot pass from the valve chest to the exhaust
passage and further, the annular groove G, through the travel of the valve
pistons, has been brought opposite the exhaust passage Q, and the rear of valve
cylinder C, thus put open to exhaust through passage B, annular groove G, and
said passage Q. The valve V will now have uncovered port K, so that steam or
air in the valve chest will pass to the rear of main piston P and effect the forward
stroke. On the completion of the full forward stroke, passage A is opened to the
live air or steam in the main cylinder, which flows through such passage,
annular groove F, and passage B', to the rear of piston P-the rear of piston P
being freely open to exhaust (1) through passage B, annular groove Gand
passage Q, and (2) through passage 1, connecting valve cylinder Cwith the lower
end of main cylinder C, port J and exhaust E. Now, the area of said piston Pl
is made greater than the exposed area of the supplemental piston N―any desired
difference in area can be given-which by the pressure of the live air or steam in
the valve chest against it keeps the supplemental piston M firmly against the end of
3

page_text: cylinder Y, so that the pressure on piston N is overcome, and pistons P¹, M, N
and P2 and valve V are caused to move backwards. In its travel piston P¹ now
covers passage A, and uncovers passage D connecting cylinder C¹ with the top end
of main cylinder C, thereby maintaining full pressure of air or steam in the valve
cylinder ¹ then supplemental piston I emerges from its auxiliary cylinder Y,-
exhaust passage Qbeing closed by the travel of piston P¹, so that live air or
steam cannot pass from the valve chest to passage Q-and supplemental
piston N enters its auxiliary cylinder Z, which cylinder is now open to exhaust
through annular groove O having been brought into communication with exhaust
passage Q. Now, in the same manner as piston M on the forward stroke was
forced against the end of its cylinder Y, piston N is forced firmly against the end
of its cylinder Z by the pressure of live air or steam in the valve chest against the
rear of piston M, and by the pressure of the air or steam in cylinder C¹, until the
pressure of air or steam in both cylinders C and C2 is brought into equilibrium by
annular groove G coming opposite passage H. At the same time the movement of
the valve will have put the space above the main piston P open to exhaust
through the passages K and E, and uncovered port J so that air or steam in the
valve chest will pass to the underside of piston P, and so effect the backward
stroke, when the action is repeated as described.
Figs. 6 to 12 show the passages H. and A. and I and D reversed, the passages H
and A. proceeding from the main cylinder being connected with the opposite valve
piston cylinders C and C², by the annular grooves F and G and passages B' and
B in the valve pistons P1 and P2, whilst passages L and D respectively connect the
valve piston cylinders C and C2 direct to the same end of the main cylinder C,
either through the main supply and exhaust ports J and K, or by independent
passages. In this arrangement the valve pistons P1, P2, M, N, and the valve V
will be caused to reciprocate in a similar manner to that above described.
In Figs. 8 to 12 inclusive the drill is shown as being provided with a piston form
of valve.
If desired the additional passages Q, Q, in the valve piston cylinders C¹, C²,
and which passages are permanently open to exhaust may be employed in place of
the passages D and I (no matter whether such passages lead from the valve piston
cylinders to the opposite ends of the main cylinder C, or to the same end thereof)
or they may, as above described, be employed in addition thereto.
In all the arrangements described a rod S projecting through one end of the
valve chest is provided to enable the valve to be pushed over when necessary in
starting the engine.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The combination with the main cylinder of a percussive rock drill or other
motor having a reciprocating piston and a valve actuated by pistons working in
cylinders formed in the valve chest, and having passages leading therefrom into
the main cylinder, so that the reciprocation of the main piston in the latter will
control such passages, and each valve piston having a passage formed in it, leading
from the rear thereof to a point on its periphery intermediate of its length, of a
passage permanently open to exhaust in each valve piston cylinder and in such a
position that when the valve piston which works therein is at the end of its
outward stroke in such cylinder, the said passage will communicate with the
passage formed in the valve piston and leading to the rear thereof, substantially as
and for the purpose specified.
2. The combination with the main cylinder of a percussive rock drill or other
motor having a reciprocating piston and a valve actuated by pistons working in
cylinders formed in the valve chest, and having passages leading therefrom into
the main cylinder, so that the reciprocation of the main piston in the latter will
control such passages, and each valve piston having a passage formed in it, leading

page_text: from the rear thereof to a point on its periphery intermediate of its length, of
two supplemental pistons of larger diameter than but formed in one with the
valve pistons, and carrying the valve for controlling the supply and exhaust to and
from the main cylinder between them, such supplemental pistons working in
auxiliary cylinders provided in and opening into the valve chest, a groove or part
of less diameter than the valve pistons being provided between each of the latter
and of the supplemental pistons, while a port or passage permanently open to
exhaust is arranged in each valve piston cylinder, in such a position that when the
supplemental piston is at the end of its inward stroke in its cylinder, such passage
communicates with the bottom of said cylinder through the groove or part of
reduced diameter, while when the supplemental piston leaves its cylinder, such
passage is cut off by the valve piston, substantially as and for the purpose
specified.
3. The combination with the main cylinder of a percussive rock drill or other
motor having a reciprocating piston and a valve actuated by pistons working in
cylinders formed in the valve chest, such cylinders having passages leading therefrom
into the main cylinder, so that the reciprocation of the main piston in the latter will
control such passages, and cach valve piston having a passage formed in it,
leading from the rear thereof to a point on its periphery intermediate of its length,
of two supplemental pistons of larger diameter than but formed in one with the
valve pistons, and carrying the valve for controlling the supply and exhaust to and
from the main cylinder between them, such supplemental pistons working in
auxiliary cylinders provided in and opening into the valve chest, a groove or part
of less diameter than the valve pistons being provided between each of the latter
and of the supplemental pistons, while each valve piston cylinder is provided with
a port or passage which is permanently open to exhaust, and is arranged in such a
position that when the valve-piston is at one end of its stroke in its cylinder, such
passage communicates with the passage formed in the valve piston and leading to
the rear thereof, while when the valve piston is at the other end of its stroke, the
passage which is permanently open to exhaust communicates with the bottom of
the cylinder in which the supplemental piston works, through the groove or part of
reduced diameter between the valve piston and the supplemental piston, all
substantially as and for the purposes specified.
Dated this 9th day of April 1891.
ALLISON BROS.,
Agents for the Applicants.