IMPROVEMENTS IN WORKING THE VALVES OF STEAM ENGINES
Year: 1857

page_text: (This Invention received Provisional Protection, but notice to proceed with the
application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by John Grantham and Henry
Sharp at the Office of the Commissioners of Patents, with their
Petition, on the 4th July 1857.
We, JOHN GRANTHAM and HENRY SHARP, of Liverpool, in the County of.
Lancaster, Engineers, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN WORKING THE VALVES OF STEAM ENGINES," to be as follows:-
The object of the present Invention is to improve and simplify the present
methods of working the valves connected with the cylinders of steam engines.
It is proposed to work a countershaft parallel to the main shaft by means of
spur wheels or other mechanical contrivances. This shaft will be so situated
as to be easily connected to the rods which work the valves, and on it will be
placed the usual excentrics, cams, or cranks, to give motion to the valve rods,
and also the wheel through which it will receive motion from the main shaft.
This wheel will not be keyed to the shaft, but will be connected by a stop on
the shaft acting upon a corresponding stop on the boss of the wheel, each stop
being so formed that the wheel can move round its axis a portion of a circle
when the engine has to be reversed. In addition to the parts already
described there will be attached to the boss of the wheel on the countershaft
a hollow tube, on the outside of which will be one or more long spiral pro-
jections forming about half the pitch of a perfect screw; on this shaft also will

page_text: be another tube or nut made to enclose the former one, and having grooves
corresponding to the spiral inclines above described, which is made to slide on
the shaft, but having two keys to cause the shaft to revolve with it. At one
end of this tube will be a collar and hoop, by which, and by the intervention
of levers or other mechanical contrivances, it can be made to slide backwards
and forwards. The spiral inclines being thus acted upon, the relativo position
of the shaft and wheel will be changed, but as the wheel will be held in its
place by the wheel on the main shaft into which it is geared, the counter-
shaft with the excentrics upon it, together with the valves to which they are
attached, will all be moved, and thus placed in the position necessary for
reversing the engines. Or, the same motion may be produced in a simpler
manner by one end of the countershaft being made hollow with one or more
spiral grooves or slots through this hollow part, and the boss of the driving
wheel which is placed upon this hollow part has one or more straight grooves
inside it, and by means of a nut to which are attached slides or blocks fitting
into all these grooves or slots, and which can be drawn backwards and
forwards by means of a screw or other mechanical contrivances, motion can
bo given to the countershaft. The stops or driving pieces are not essential
to the Invention, but may in some cases be dispensed with. By this com-
bination of the spur wheels for working the countershaft, and of the incline or
spiral motion for altering tho position of the countershaft, the whole of the
valves, both the ordinary slides or expansion valves, may be acted upon at one
time when required for starting, stopping, or reversing the engines.