Improvements in Valves and Valve Gear for Direct-action Engines.
Year: 1895

page_text: Date of Application, 23rd Apr., 1895
Complete Specification Left, 21st Jan., 1856-Accepted, 22nd Feb., 1896
[Communicated from abroad by THE INGERSOLL SERGEANT DRILL Co., a
corporation organized under the laws of the State of West Virginia, and
having its principal business office at No. 26 Cortlandt Street, in the City of
New York, in the State of New York, United States of America.]
"Improvements in Valves and Valve Gear for Direct-action
Engines.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
This invention relates to valves and valve gear which are or may be applicable
to direct-action engines generally but which are more especially applicable to rock
drilling engines, and it relates particularly to valves which are operated by a
three-armed oscillating lever actuated by tappet surfaces on the piston of the
engine. Such valves as heretofore constructed have had straight faces and
straight sides and, that arm of the lever which engages with the valve.moving in
arcs while the valve moves in straight lines, not only was there considerable
friction between the said arm and the valve and consequently considerable wear at
the points of their engagement, but the arm exerted a tendency to draw the. valve
towards its seat and consequently to produce unnecessary friction between the
valve and seat. The object of this. invention is to remedy this defect.
The invention comprises an engine cylinder, a piston having an. annular recess
between its beads, the ends of the said recess constituting tappet surfaces. The
steam or other motive fluid is supplied to the valve-chest through an opening.
I provide a three-armed valve-operating lever, a stationary pin on which the
said lever oscillates. The said lever works as is usual, within an opening in the
top or one side of the cylinder, its two tappet arms entering the bore of the cylinder
and its valve actuating arm projecting outwards from the opening in the cylinder
through a corresponding opening in the valve-seat and projecting beyond.the.valve-
seat into a recess provided for it in the valve. The openings in the cylinder and
valve-chest are in communication by a side passage with the exhaust opening.
The valve is what is known as the double D kind, but the arrangement of its
ports and the ports in its seat are immaterial to this invention. The valve-seat is
of the form of a convex cylindrical arc the centre or axis of which corresponds
with the axis of the pin upon which the three-armed lever oscillates. The face of
the valve is in the form of a corresponding concave cylindrical arc. The operative
faces of the arm of the lever and the corresponding faces of the recess in the valve
are of flat form, so that the contact between the said faces of the arm and the
faces of the recess is distributed over a considerable surface.
By reason of the faces of the valve and its seat being in the form of ares.the
centre of which corresponds with the axis of oscillation. of the lever, the arm.
operates on the valve with a dead push and without any friction and without any
tendency of the end of the valve-operating arm to wear cavities in those faces in
the recess of the valve against which they operate and to hook itself into those
cavities in such manner as to pull the valve towards its seat which has been a
great defect with flat valves operated by such a lever. The absence of friction
"between the arm and the valve permits a larger area of contact between the

page_text: operating faces of the arm and the corresponding faces of the recess in the valve,
and this permits the cavity to be made so much wider than the tappet arm so that
the valve may have a stroke considerably longer than the arm which is of
considerable advantage as the length of oscillation of the lever is necessarily
limited.
Dated this 16th day of April 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in Valves and Valve Gear for Direct-action
Engines.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 valves and valve gear which are or may be applicable
to direct-action engines generally but which are more especially applicable to rock
drilling engines, and it relates particularly to valves which are operated by a three-
armed oscillating lever actuated by tappet surfaces on the piston of the engine,
Such valves as heretofore constructed have had straight faces and straight sides.
and, that arm of the lever which engages with the valve moving in arcs while the
valve moves in straight lines, not only was there considerable friction between the
said arm and the valve and consequently considerable wear at the points of their
engagement, but the arm exerted a tendency to draw the valve towards its seat
and consequently to produce unnecessary friction between the valve and seat.
The object of this invention is to remedy this defect.
I will now proceed to describe the invention with reference to the accompanying
drawing in which
Figure 1 represents a longitudinal section of a portion of the cylinder and of
the valve-chest, valve and valve gear of a rock drilling engine embodying this
invention.
Figure 2 represents a transverse section on the line 2, 2, of Figure 1.
Similar letters of reference designate corresponding parts in all the figures.
A designates a portion of the engine cylinder, B the piston having an annular
recess between its heads, the ends a a¹ of the said recess constituting tappet.
surfaces. C is the valve-chest to which the steam or other motive fluid is supplied
through an opening C¹..
D is the valve and bits seat. E is the three-armed valve-operating lever,
and the stationary pin on which the said lever oscillates. The said lever E
works as is usual, within an opening d in the top or one side of the cylinder, its two.
tappet arms e e entering the bore of the cylinder and its valve actuating arm f pro-
jecting outwards from the opening d in the cylinder through a corresponding
opening d in the valve-seat and projecting beyond the valve seat into a recess g
provided for it in the valve. The openings dd in the cylinder and valve-chest
are in communication by a side passage with the exhaust opening F.
The valve D is what is known as the double D kind, but the arrangement of its
ports and the ports in its seat are immaterial to this invention. The valve-seat b
is of the form of a convex cylindrical are the centre or axis of which corresponds
with the axis of the pin c upon which the three-armed lever E oscillates. The
face of the valve is in the form of a corresponding concave cylindrical arc. The
operative faces of the arm f of the lever and the corresponding faces of the recess g

page_text: in the valve are represented as of flat form, so that the contact between the said
faces of the arm f and the faces of the recess g is distributed over a considerable
surface.
By reason of the faces of the valve and its seat being in the form of arcs the
centre of which corresponds with the axis of oscillation of the lever E, the arm f*
operates on the valve with a dead push and without any friction and without the
tendency of the end of the valve-operating arm to wear cavities in those faces in
the recess of the valve against which they operate and to hook itself into those
cavities in such manner as to pull the valve towards its seat which has been &
great defect with flat valves operated by such a lever. The absence of friction
between the arm and the valve permits a larger area of contact between the
operating faces of the arm and the corresponding faces of the recess g in the valve,
and this permits the cavity to be made so much wider than the tappet arm as
indicated at g in Figure 1, that the valve may have a stroke considerably longer
than the arm which is of considerable advantage as the length of oscillation of
the lever is necessarily limited.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
The combination with an engine cylinder and a piston therein provided with
tappet surfaces, of a valve-seat having a convex arc-formed profile, a valve having
a corresponding concave profile and a three-arned oscillating lever having its axis
of oscillation corresponding with the centre of the arc of the valve and seat, one of
the arms of said lever engaging with the valve and the other two constituting
tappets to be acted upon by the tappet surfaces of the piston, substantially as herein
set forth.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.