IMPROVEMENTS IN EXPANSION AND REVERSING GEAR FOR STEAM AND OTHER FLUID-PRESSURE ENGINES
Year: 1878

page_text: PROVISIONAL SPECIFICATION left by Sydney Herbert Hollands at the
Office of the Commissioners of Patents on the 7th October 1878.
SYDNEY HERBERT HOLLANDS, of Old Kent Road, London. "IMPROVEMENTS
IN EXPANSION AND REVERSING GEAR FOR STEAM AND OTHER FLUID-PRESSURE
ENGINES."
The object of this Invention is the substitution of a more simple and more easily
worked mechanism for the ordinary link motion of steam engines.
In describing the nature of my Invention I will suppose it to be applied to a
vertical steam engine. I make a T shaped lever, the upper or horizontal portion of
which is slotted out to the usual link shape.
Immediately below the link and at or near the point of intersection of the vertical
with the horizontal portion of the lever, I mount this latter on a fixed pin in such
manner that it is free to oscillate or turn on the same; I also slot out the vertical
portion of the T shaped lever commencing a short distance below the point of
Oscillation and ending near its lower end. I fit the vertical slot with a sliding block
bored out to receive a crank pin attached to the crank or crank shaft or any other
suitable part, which shall have the effect of causing such pin to describe an
eccentric movement and thereby a vibrating or rocking motion of the T shaped
lever on the fixed pin before mentioned; I also fit a sliding block to the slot in the
upper or horizontal arm of the T lever the travel of which block I govern by means
of a hand lever brought into connection with such block by means of a suitable
rod;
the lower end of the hand lever turns on a fixed pin, and such lever is held
in position and adjusted by being made to gear into a toothed sector. I joint the
slide valve rod to the sliding block in the horizontal arm of the T lever, having done
which I work my Invention in the following manner :-
I start the engine by actuating the hand lever so as to fix the sliding block in
the horizontal arm of the T lever at any point on either side of the centre of
oscillation when the eccentric motion of the crank pin connected to the vertical
arm of the T lever causes this latter to oscillate with the fixed pin as a centre
and thus operates the slide valve rod jointed to the sliding block in the horizontal
Prine 971

page_text: arm of the T lever. By shifting the 'sliding block nearer to or away from the
centre of oscillation the travel of the slide valve is shortened or lengthened, thus
being a means of working the engines expansively, and when the block is shifted
to a central position the engine is stopped.
Although in describing the nature of my Invention I have supposed it to be
applied to a vertical steam engine it is equally applicable to all other kinds of
steam engines, and although I have described the oscillating lever as a T shaped
lever such shape may be varied without affecting the principle of my Invention;
for instance, instead of the vertical arm of such oscillating T lever I may
employ an open rectangular frame in one piece with the horizontal arm, such
rectangular frame being fitted with adjustable bearings for a crank pin, cam
eccentric, or other medium for causing the oscillating lever to operate and with it
the slide valve.