Automatic Variable Expansion Gear for Steam Engines.
Year: 1892

page_text: Date of Application, 28th Nov., 1892
Complete. Specification Lelt, 28th Aug., 1893-Accepted, 30th Sept., 1893
PROVISIONAL SPECIFICATION.
Automatic Variable Expansion Gear for Steam Engines.
JAMES MEREDITH AUSTIN The Junior Constitutional Club Regent Street
London, S. W., Mechanical Engineer do hereby declare the nature of this invention
to be as follows:-
This invention relates to automatic expansion gear for steam engines.
In the accompanying drawing
Fig. 1 shows a longitudinal section, and Fig. 2 an elevation of the gear for
regulating the cut off of one valve.
The horizontal lever B is worked by the eccentric through the arm B1,
it engages with the bell crank A. A 1 at Al thereby raising the valve spindle C. C 1
until the toe of the bell crank A 1 is made to trip off the horizontal lever B by the
stop D. The different positions of D to be regulated by the governor by means
of suitable levers or otherwise.
This invention can be used for working a single expansion valve by introducing
similar gear on the other side of the valve spindle C. C 1 whereby two beats of the
valve per revolution can be obtained.
Dated this 98th day of Novambox 1909
COMPLETE SPECIFICATION.
Automatic Variable Expansion Gear for Steam Engines.
I, JAMES MEREDITH AUSTIN, of The Junior Constitutional Club, Regent
Street, in the County of London, Mechanical Engineer, 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 :-
My invention relates to automatic variable expansion gear for steam engines and
it comprises a lever or a lifting or rocking arm operated by an eccentric, crank or
other suitable means; a bell crank pivotted to the valve spindle, with one arm of
which bell crank the lever engages; a stop for tripping the bell crank from the
lever and mechanism for allowing the tripping position of the stop to be regulated
by the governor.
To enable my invention to be fully understood I will describe how it can be
carried into practice by reference to the accompanying drawing, in which :-
Figure 1 is an elevation partly in section of part of a horizontal engine fitted
with two double beat valves provided with my improved expansion gear:
Figure 2 is an elevation of the gear at right angles to Figure 1:
Figure 3 is an elevation of part of the mechanism; and,
Figure 4 is a section illustrating the application of my invention to an engine
provided with a slide-valve.
Similar letters in all the figures indicate similar or corresponding parts.
I will first describe my invention by reference to Figures 1, 2 and 3.
a, a, Figure 1, are the spindles of the two valves, one of which is shewn at 6;
c is the fever or lifting arm fixed to a shaft d, Figures 1 and 2, working in a-
bearing a in the support e of each valve and operated by an eccentric, crank or
other suitable means, not shewn in the drawing, through the medium of an arm f
jointed to a rod g; hand are the two arms of the bell crank pivotted at j on the
valve-spindle a; the arm h is notched at k to engage the end of the lever c which
by this means is caused to lift the valve as the eccentric, crank or the like operates
[DO1

page_text: the said lever; is the stop pivotted at m to the valve-support e, against which stop
the arm of the bell crank bears as the valve b rises, thereby tripping the arm
of the bell-crank from engagement with the lever at a variable point in the
ascent of the valve b and allowing the valve to return to its seat, the said point
being regulated by the governor of the engine in the following manner :-
A horizontal shaft n is mounted in a bracket o on a standard p in which the
governor-spindle q slides, the shaft being caused to oscillate as the governor-spindle
rises and falls by means of a lever r, Figure 3, one end of which is fixed to the
shaft and the other end of which is confined between two collars s, on the
governor-spindle q. At each end of the shaft n is a cam t, as shewn in Figure 1,
which cam, as the shaft n oscillates, bears against the stop and moves it towards
the right hand, into the position by way of example shewn by the dotted lines,
or allows it to be moved in the opposite direction by a spring provided for this
purpose.
The arrangement illustrated in Figure 4 for actuating a slide-valve is the same
as that described with reference to Figures 1, 2 and 3 except that the shaft n is
placed vertically, the motion of the governor-spindle heing communicated to the
stop by the cam t acting on an inclined piece u carried by an arm: v. fixed to the
stop l, and the lifting arm c is carried by a bar w which is vertically reciprocated in
a bracket a by suitable means from the eccentric, crank or the like.
If required the gear can be thrown out of action by simply providing the stop
with a hand lever, or a lever or equivalent means arranged to be operated from a
distance by electricity or otherwise.
By transmitting the motion of the governor by the means hereinbefore described
all shock or strain to the same is avoided.
When applying my improved gear to the slide-valves of horizontal engines I
employ a rocking arm instead of a lever or a lifting arm for actuating the valve,
which rocking arm is adapted to move the valve in a horizontal direction.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. An automatic variable expansion gear for steam engines comprising a lever or
a lifting or rocking arm operated by an eccentric, crank or other suitable means, a
bell crank pivotted to the valve spindle, with one arm of which bell crank the
lever or arm engages, a stop for tripping the bell crank from the lever or arm
and mechanism for allowing the tripping position of the stop to be regulated by the.
governor, substantially as hereinbefore described.
2. The improved automatic variable expansion gears for steam engines herein-
before described and illustrated in Figures 1, 2 and 3 and Figure 4 of the
accompanying drawing.
Dated this noch d..
1000
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.