Improvements in Rock Drilling Machines, also applicable to Pumps.
Year: 1896

page_text: Date of Application, 15th Feb., 1896-Accepted, 28th Mar., 1896
COMPLETE SPECIFICATION.
Improvements in Rock Drilling Machines, also applicable to Pumps.
We, JAMES WILLIAM LARMUTH and ROBERT BIRKEN HOWARTH, Engineers, both
of the Todleben Ironworks, Salford in the County of Lancaster 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 percussive rock drilling machines and direct acting
pumps operated by steam, compressed air, or other pressure fluids, arranged either
as a simple high pressure or a compound machine, and consists of improvements
in construction and arrangement of the piston valve and the piston rod gland of
said machines. Our improvements relating to the piston valve have for their object
that when the machine is being used in a vertical or angular position the piston
valve shall fall by its weight into the proper position for starting the rock drill or
pump without having to be operated from the outside, and further to economize
the compressed air or other motive fluids and to remove the destructive shocks
common to fluid operated piston valves by providing an effective fluid cushion at
the ends of the piston valve. The object of our improvements in the piston rod
gland is to provide in a solid head a means of firmly locking the gland on the nose
of the front cover or solid head.
Our improvements are hereinafter particularly described with reference to the
three accompanying sheets of drawings on which
Figure 1 is a central longitudinal section of our improved simple high pressure
rock drill illustrating our improved piston slide valve, valve box, main cylinder with
its piston rod, solid head and improved locking spring gland to same.
Figure 2 is a plan showing an exterior view and part section of Figure 1.
Figure 3 is a cross section of the improved piston rod gland.
Figure 4 is a central longitudinal section showing the application of our
improvements to a compound rock drill.
Figure 5 is a plan showing an exterior view and part section of Figure 4.
Figures 6 and 7 are cross sections on lines A B and CD Figure 1, the piston
being shewn in section at the recessed part hereinafter referred to.
Figure 8 is a sectional plan of the valve box on lines E F Figure 1.
Figures 9 and 10 are cross sections on lines G H and IJ, Figure 4, with the
piston shown in section at the recessed part.
Figure 11 is a sectional plan of the compound valve box on lines K L, Figure 4.
Like letters indicate the same parts throughout the drawings.
In carrying out our invention we provide a cylinder A Figure 1, having the
cylinder ports B' and B2, the admission port D¹ and the two exhaust ports E and E2
formed therein. On the top of this cylinder we form or attach by means of bolts s
short valve box F provided with corresponding ports meeting or communicating
with the above ports, also the small exhaust ports G and G2, Figures 1, 6 and 8
and which ports G' and G2 are arranged at a short distance from the inside face of
the valve box plugs or covers P and P. We form corresponding ports H' and H
at the side of the main cylinder shewn in dotted lines in Figure 1 and in cross
section in Figure 6 and which ports H' and H2 communicate with the interior of
the cylinder A', Figures 1 and 6. We also form in the side of the cylinder opposite
to the ports H' and H2, two escape ports 1' and I2 (shown in part section on Figure 2
and in cross section on Figure 6) leading from the interior of the main cylinder A',
Figure 1, into the two main exhaust ports J and J2 shown in dotted lines on

page_text: Figure 1 and in cross section on Figure 6. We provide the valve box F' with a
double ended piston valve K, having the central chamber L formed therein, also the
two exhaust chambers M and M', Figures 1 and 6, and we form in the sides of the
piston valve the small inlet ports N and N, Figures 6 and 8, and cut in the interior
at each end of the valve box F', Figures 6 and 8, the two small corresponding
connecting ports O and O'. The ends of the valve box F¹ are closed by means of
the screwed plugs or covers P and P1, Figure 1.
We provide the cylinder A' with the piston rod R, Figure 1, having
chamber S formed in the centre or between the two piston faces S1 and S2.
a recess or
The improved rock drill or pump arranged and fitted with a piston valve as
hereinbefore described operates as follows:-
The drawing Figure 1 shows the piston slide valve, in the position for admitting
pressure fluid to the back end T of the piston causing the piston to make its
outwards or boring stroke, the front end of the cylinder A' being open to the
atinosphere through the ports B₁, chamber M and exhaust port E' leading to the
anáin exhaust port J', shown in dotted lines Figure 1 and in cross section Figure 6.
When the piston valve is in this position fluid pressure is admitted froin the central
chamber L to the back end of the valve box F by means of the small port N¹
in the piston valve K' and the connecting ports O' formed in the ends of the valve
box F, the corresponding ports O and N at the other end of the piston valve K¹
being closed to the admission of fluid pressure. At the same time the escape
ports G¹ H¹ and I' are closed by the piston S'. Just after the piston has started, the
recess or chamber S puts the port H* into communication with the exhaust port 1³
and J', whereby the pressure fluid at the back of the valve K' is exhausted, which
tends to hold the valve in its position. After the piston face S has closed the
port H2 pressure is reestablished at the back end of the piston valve through the
ports O' and N¹ as before. When the piston S' and S has travelled near to the end
of its outward stroke, the recess or chamber S formed in the piston faces S' and S*
Figure 1 opens an outlet to the atmosphere through the escape ports G' H' and I'
Figures 1, 6 and 8, and by means of the fluid pressure on the opposite end the
piston valve is operated and shifted to the left. When the piston valve has travelled
part of its stroke, it closes the port G' and opens at the same time the two small
ports O and N formed in the sides of the piston valve faces and interior of the
valve box at each end, the closing and opening of the above ports, first prevents the
waste of the motive pressure fluid, and secondly, the admission of the fluid pressure
to the end of the piston valve K' at nearly the end of its stroke provides a fluid
cushion to prevent all damage to the piston valve. On the return stroke of the
piston the valve is shifted to the back end in an analogous manner when the
recess S places the ports G H into communication with the exhaust ports I'
and J. By these means the piston valve is operated and automatically cushioned
without any shock or loss of fluid pressure other than what is required to operate
the same as described above.
Our improved piston valve and valve box with a small modification may be
applied to a compound rock drill having a cylinder and starting valve arranged
in a similar manner to the one described in our Patent Specification No. 5416
A.D. 1894. In this case we arrange the piston valve K' with an additional admission
chamber U, Figures 4 and 11, exhausting the fluid pressure into a receiver pipe V,
Figures 4 and 5. After the piston has made its outward or boring stroke this
additional admission chamber V serves to direct the pressure fluid to the enlarged
or low pressure end of the rock drill cylinder or pump. With this exception, the
remainder of the piston valve and its valve box (when applied to a compound rock
drill, or pump) is of the same construction as in the case of the simple high pressure
rock drill or steam pump and acts in a similar manner.
When the rock drill is not in use and in a vertical or inclined position, the
piston and valve will slide to the front end and both be in the required position
for starting when the fluid pressure is turned on, the starting valve being used in
the case of a compound drill in the manner described in our said Specification.

page_text: Our further improvement in rock drills is connected with the solid head or
front cover and consists in improved means for locking the screwed gland cap (on
the nose of the solid head) .when the rock drill is in use."
In carrying out this part of our invention we provide the nose of the solid
head W Figures 1, 2, 3, 4 and 5 with a split gland cap X having a screwed
thread formed therein to suit the thread on the nose of the solid head.` We provide
the split gland cap X as shown by Fig. 3 with lugs on each side and by means
of a bolt Y passing through the centre of same we are enabled to tighten or jam
the split gland cap X on the nose of the solid head and so prevent the split gland
cap shaking loose when the rock drill is in operation.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare what we
claim is:
Firstly. In a percussive rock drilling machine or direct acting pump, the
arrangement of the main piston and its recess and exhaust chamber, the piston
valve, its ports and exhaust chambers, the valve box and its ports for operating
the piston valve and piston, substantially as herein before described and illustrated
and for the purpose set forth.
Secondly. In a percussive rock drilling machine or direct acting pump the
arrangements of a piston valve constructed in such a manner that it will
automatically drop into a starting position when being used in a vertical or angular
position without the assistance of the motive pressure Huid, constructed substantially
as hereinbefore described, and illustrated by the drawings.
Thirdly. In a compound rock drilling machine or direct acting pump the
arrangement of a piston valve provided with an additional admission chamber or
port, the valve box, and main piston, substantially as hereinbefore described and
illustrated by the drawings.
Fourthly. The use and construction of a split gland cap and bolt for locking the
same on the nose of the solid head substantially as hereinbefore described and
illustrated by the drawings.
Fifthly. The general arrangement or construction of a non expansive rock
drilling machine or pump substantially as hereinbefore described and illustrated in
the drawings.
Sixthly. The general arrangement or construction of a compound rock drilling
machine or pump substantially as hereinbefore described and illustrated by the
drawings.
R. J. URQUHART,
57, Barton Arcade, Manchester, and 5, Clayton Square, Liverpool,
Consulting Engineer and Patent Agent,