Improvements in Valve-operating Gear for Steam Engines.
Year: 1891

page_text: Date of Application, 6th Nov., 1891-Accepted, 12th Dec., 1891
COMPLETE SPECIFICATION.
Improvements in Valve-operating Gear for Steam Engines.
A communication from the firm of GEBRUDER SACHSENBERG, of. Rósslau, on the
Elbe, in the Empire of Germany.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 :-
The object of this improved valve-gear for steam-engines is to enable the supply
of steam to each cylinder so to be varied according to requirements, indepen-
dently of the other cylinder or cylinders and without the employment of eccentrics
or any special expansion devices.
The invention will be best understood by reference to the accompanying drawings
in which Fig. 3 is a diagram of the knee-lever mechanism pivotted at M which in
vertical engines is arranged upon the bed-plate near to the crank shaft and in
horizontal engines above, the said shaft being adjustable in both cases either by
hand only or by hand and by a governor at the same time.
The real fulcrum or point of support of this entire lever arrangement is at M
which point is adapted to describe an arc of a circle whose radius equals the length
of the swinging arm or link M N and which is guided by a slide C (Fig. 2) and
it is upon the displacement of this fulcrum that the distribution of the steam
depends.
This fulcrum or pivot M may by moving the slide C in the direction of the shaft
be so adjusted that the direction of motion of the engine is reversed.
On this pivot swings the link M N (Fig. 3), the upper end N of which describes
the arc of a circle the extreme limits of which determine the length of the link or
rod NO which imparts to the valve mechanism the motion it receives from the
connecting-rod PQ of the engine.
The slide valve receives motion through the rod RS from the said rod NO at R
which point is situated between N and Ŏ at a distance from N to be determined
according to circumstances. The rod RS is the means of conveying the motion
to the slide-valve and for this purpose it engages the cross-head of the valve-rod
at its upper end S.
By this arrangement and with the assistance of diagrams of the different
cylinders previously taken, the extent to which these cylinders should be supplied.
with steam so as to correspond to the given condition of the high pressure cylinder
may at all times readily be ascertained and the desirable uniformity of operation
ensured.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondents and in what manner the
same is to be performed, I declare that what I claim is :-
1. A valve-gear for steam engines or cylinders in which motion is imparted to
the steam distributing slide-valve from any point of the connecting rod of the
engine the said valve-gear being characterized by a lever and link mechanism con-
sisting of a rod or link such as NO connecting the connecting-rod of the engine
with the link RS which operates the valve rod and to a point R of which the said
link RS is jointed (the situation of the point R being fixed according to the
requirements of each case) for the purpose of adjustably transmitting the motion
of the connecting rod to the valve rod which result is obtained by the whole of the
lever and link mechanism being pivotted at one adjustable point M carried in a
curved slide and adjustable according to a scale fixed to the said slide either by

page_text: hand only or by hand and also by the action of a governor substantially as described
and illustrated in the diagram Figure 3 of the accompanying drawings.
2. In a valve-gear such as described the extensibility of the slide C.or point M
in the direction of the engine shaft for the purpose of reversing the motion of the
engine substantially as described and illustrated in the diagram Fig. 3 of the
accompanying drawings.
Dated this 6th day of November 1891.
W. P. THOMPSON & BOULT,
Agents for the Applicant.