IMPROVEMENTS IN VALVE-GEAR FOR. STEAM-ENGINES."
Year: 1881

page_text: LETTERS PATENT to Robert Henry Robinson, of Marlpool House, near
Derby, in the County of Derby, for an Invention of "IMPROVEMENTS IN
VALVE-GEAR FOR. STEAM-ENGINES."""
PROVISIONAL SPECIFICATION left by the said Robert Henry Robinson at
the Office of the Commissioners of Patents on the 5th May 1881.
ROBERT HENRY ROBINSON, of Marlpool House, near Derby; in the County of
Derby. "IMPROVEMENTS IN VALVE GEAR FOR STEAM ENGINES."
My Invention has for its object an improved construction of gear or apparatus
for opening and closing lift valves of steam engines, whereby the motion is
imparted to such valves in a very simple and direct manner, and noise is
obviated.
For this purpose the valve stems are formed with slots or have looped pieces
attached to their upper ends, through which loops or slots passes a fixed bar or
bearer, on the upper face of which is a slide that is moved backwards and forwards
by a rocking lever receiving suitable motion from any convenient part of the engine,
and connected to the slide by a connecting rod.
The upper face of the slide is shaped as a cam, and upon it bears a roller. carried
on a pin in the upper end of the loop or slot of the valve rod, so that as the slide is
moved in one direction, its cam face in acting against the rollers so as to lift it,
causes the valve to be raised off its seat, while when it is moved in the opposite
direction, it allows the valve to close down on its seat again, the cam face being so
formed that the commencement and end of such motions take place very gradually,
and consequently without shock and noise.
The slide moves between guides, and it may either work directly on the face of
the bearer, or with the intervention of antifriction rollers. The sides of the loop or
slot of the valve rod also work in guides fixed to the sides of the bearer.
The steam and exhaust valves may conveniently be both worked by one and the
same rocking lever, connected by opposite rods to the slides that actuate the two
valves as described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Henry Robinson in the Great Seal Patent Office on the
3rd November 1881.
ROBERT HENRY ROBINSON, of Marlpool House, near Derby, in the County of
Derby. "IMPROVEMENTS IN VALVE GEAR FOR STEAM ENGINES."
My Invention has for its object an improved construction of gear or apparatus
for opening and closing lift valves of steam engines, whereby the motion is
imparted to such valves in a very simple and direct manner, and noise is
obviated.
'
For this purpose the valve stems are formed with slots or have looped pieces
attached to their upper ends, through which loops or slots passes a fixed bar or bearer,
.on the upper face of which is a slide that is moved backwards and forwards by a
rocking lever receiving suitable motion from any convenient part of the engine, and
'connected to the slide by a connecting rod.
The upper face of the slide is shaped as a cam, and upon it bears a roller carried
on a pin in the upper end of the loop or slot of the valve rod, so that as the slide
is moved in one direction, its cam face in acting against the roller so as to lift it
causes the valve to be raised off its seat, while, when it is moved in the opposite
direction, it allows the valve to close down on its seat again, the cam face being so
formed that the commencement and end of such motions take place very gradually,
and consequently without shock and noise.
The slide moves between guides, and it may either work directly on the
face of the bearer or with the intervention of antifriction rollers. The sides
of the loop or slot of the valve rod also work in guides fixed to the sides of the
bearer.
The steam and exhaust valves may conveniently be both worked by one and the
same rocking lever connected by opposite rods to the sides that actuate the two
Fig. 1 of the accompanying Drawing shews an elevation of the valve gear of a
steam engine constructed according to my Invention, and Fig. 2 shews an enlarged
cross section on line X, X.
The valve boxes A, A', carry a beam B on which are side guides C, in which
work loops D1, D2, D3, D, on the valve rods; within these loops are rollers & that
bear against the sliding cams E, E', sliding with a dovetail base in a corresponding
groove formed in the upper surface of the beam. These sliding cams are connected
by links F to one and the same lever G, receiving reciprocating motion from any
convenient moving part of the engine in such manner as to cause the cams E, E¹, by
their motion to correctly operate the admission and exhaust valves at each end of the
steam cylinder H, that is to say, by the motion in one direction the cam E by means
of its surface e lifts the admission valve at D', while the cam E¹ by its surface'e³
lifts the exhaust valve at D'; .and by the motion in the other direction, the cam E¹
by means of its surface e² lifts the admission valve at D³, while the cam E by means
of its surface e¹ lifts the exhaust valve at D²
Having thus described the nature of my Invention, and in what manner the same.
is to be performed, I claim,-
Actuating lift valves of steam engines by reciprocating slides working through
slots or loops on the valve rods, and having cam surfaces or inclines bearing against

page_text: rollers within the said slots or loops, so as to alternately lift the valves and allow
them to close on their seats, substantially as herein described.
In witness whereof, I, the said Robert Henry Robinson, have hereunto set
my hand and seal, this Twenty-second day of October, in the year of our
Lord One thousand eight hundred and eighty one.
ROBERT HENRY ROBINSON. (L.S.)