Improvements in Apparatus or Machinery for Drilling Rocks and other Hard Substances.
Year: 1896

page_text: Date of Application, 23rd Jan., 1896
Complete Specification Left. 14th Oct., 1896-Accepted, 9th Jan., 1897
VISIONAL SPE
Improvements in Apparatus or Machinery for Drilling Rocks and
other Hard Substances.
We, RICHARD STEPHENS and WILLIAM CHARLES STEPHENS, both of Carn
Brea, in the County of Cornwall, Engineers, do hereby declare the nature of this
invention to be as follows:-
This invention relates to improvements in apparatus or machinery for drilling
rocks and other hard substances of the kind described in the Specification of our
former Letters Patent No. 2053 of 1890, the said improvements having for object
to increase the efficiency of such apparatus.
According to this invention, instead of actuating the oscillating valve by means
of a single protuberance on the piston-rod between the two pistons or piston heads
as described in our said former specification, we now actuate the said valve by
means of two inclined surfaces on the said piston, such inclined surfaces being
advantageously obtained by tapering the inner ends of the two piston heads.
We also fasten the pin carrying the oscillating valve to the valve chest by plugs
or stoppers screwed through the walls of the valve chest.
To prevent leakage between the pistons and the cylinder we provide the former
with packing rings of leather held against the surface of the cylinder by means of
springs.
Dated this 23rd day of January 1896
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.
Improvements in Apparatus or Machinery for Drilling Rocks and
other Hard Substances.
We, RICHARD STEPHENS and WILLIAM CHARLES STEPHENS, both of Carn
Brea, 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 ascertained in and by the following statement :-
This invention relates to improvements in apparatus or machinery for drilling
rocks and other hard substances of the kind described in the Specification of our
former Letters Patent No. 2053 of 1890, the said improvements having for object
to increase the efficiency of such apparatus.
According to this invention, instead of actuating the oscillating valve by means
of a single protuberance on the pistou-rod between the two pistons or piston heads
as described in our said former specification, we now actuate the said valve by
means of two inclined surfaces on the said piston-rod, such inclined surfaces being
advantageously obtained by tapering the inner ends of the two piston heads.

page_text: We also fasten the pin carrying the oscillating valve to the valve chest by-plugs
or stoppers screwed through the walls of the valve chest.
To prevent leakage between the pistons and the cylinder we provide the former
with packing rings of leather held against the surface of the cylinder by means of
springs.
In lieu of the usual split front cover of the cylinder we employ a solid cover
having a hole through which a leather or other packing ring can be inserted and
which is provided with an air tight plug or stopper.
To enable our invention to be fully understood we will describe it by reference
to the accompanying drawing, in which :-
Figure 1 is a longitudinal section of a percussive drill having our improvements
applied thereto :
Figure 2 is a plan partly in section of the same :
Figure 3 is a detail view drawn to an enlarged scale sbewing the leather packing
ring for the piston:
Figure 4 is a section of the front cover on the line 4-4, Figure 1.
a is the cradle, & the cylinder which slides in the same and c the screw by means
of which the cylinder is caused to slide in the cradle a. d is the piston-rod, e, f the
pistons or piston heads and f¹ the twist bar.
9 is the valve chest and h, the ports opening from the same into the cylinder b;
is the oscillating valve mounted on the pin which passes through the sides of
the valve chest into the plugs or stoppers k, k screwed into bosses 1, 1 on the said
sides.
m is a bush, preferably of brass or gun metal, on the pin j, on which bush the
valve is loosely mounted. n is a spiral spring arranged on the bush m and
adapted to keep the valve i in contact with the valve face. o, o are buffers of
elastic material fitted into the valve chest cover g' and designed to act as stops to
the valve.
p, p are the inclined surfaces on the piston-rod, such inclined surfaces being
formed by tapering the inner ends of the piston heads e and f.
9, 9 are rings of leather arranged in the grooves r, r in the piston heads, as
shewn clearly in Figure 3, the said rings being held against the cylinder by the
springs 3, 3.
During the movement of the piston these inclined surfaces alternately come in
contact with the ends of the valve i thereby causing the same to oscillate on the
pinj so as to control the passage of the motive fluid.
t is the solid front cover of the cylinder b, and t is a groove in the same for the
reception of a split leather or other packing ring t. 3 is the hole through which
the packing ring is passed into the groove t and is the screw plug for closing the
said hole air-tight. By this construction of solid front cover it will be obvious
that a worn packing ring can be easily and quickly renewed without disturbing the
front cover which was necessary with covers as heretofore made.
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. In apparatus or machinery, for drilling rocks and other hard substances,
wherein a piston or pistons is or. are operated by a motive fluid controlled by an
oscillating valve, inclined surfaces on the piston-rod for the purpose of actuating
the said valve, substantially as described.
2. In apparatus or machinery for drilling rocks and other hard substances,
wherein a piston is operated by a motive fluid, leather packing rings on the piston,
such rings being held against the cylinder by means of springs.
3. In apparatus or machinery for drilling rocks and other hard substances
(wherein a piston and an oscillating valve loosely mounted upon a pin are employed)
hollow plugs or stoppers passing through the sides of the valve chest and supporting
the said pin, substantially as described.

page_text: 4. The combination in a rock drill, of pistons, an oscillating valve, inclined
surfaces on the piston-rod for operating the said valve, elastic stops for the valve
and leather packing rings arranged in the pistons, substantially as described.
5. The combination with apparatus or machinery for drilling rocks and other
hard substances wherein a piston or pistons is or are operated by a motive fluid
controlled by an oscillating valve the piston rod having inclined surfaces for
actuating the said valve as claimed in Claim 1, of a solid front cylinder cover
having a hole for the insertion of the packing ring and a plug or stopper for the
same, substantially as, and for the purpose, herein before described.
Dated this 14th day of October 1896
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.