Year: 1886

page_text: Date of Application, 30th Oct., 1886.
Complete Left, 18th June, 1887.
Complete Accepted, 19th July, 1887
I, MAX HIRSCH trading as Bolzano Tedesco and Co. of Schlan, Austria, Engineer
do hereby declare the nature of this invention to be as follows :-
This invention relates to a variable expansion gear for the movement of the steam
valves in Corliss engines and consists in combining with the ordinary actuating disc
a T shaped or three armed lever which is pivotted to the face of the disc towards its
outer edge. The two opposite arms of the lever are connected to the rods which
actuate the inlet valves the ends of the rods striking against blocks sliding in guides
in the usual manner. The rods themselves are pivotted to sliding blocks and have
therefore a reciprocatory and vertical oscillatory motion. The third arm of the lever
is connected with and operated by the expansion eccentric which imparts a rocking
motion to it the effect of which is to vary the motion of the rods actuating the valves.
By means of this combination of two eccentrics the rods may be caused to encounter
the sliding blocks very slowly or without shock thereby reducing the wear of the parts
in contact. As the actuating rod gradually rises during the whole of the valve
opening stroke the liberation of the valve slide block may take place at any point
thereof which is not possible in the usual Corliss gear where the liberation generally
only takes place during the opening half of the stroke. With this arrangement the
selection of the lead angle is therefore not restricted which is very desirable. The
same gear may be readily adapted to other than Corliss valves.
Dated this 31st day of January 1887.

page_text: I, MAX HIRSCH trading as Bolzano Tedesco & Company of Schlan, Austria
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 :-
This invention relates to a variable expansion gear for the movement of steam valves
in Corliss engines and consists in combining with the ordinary actuating disc
a T shaped or three armed lever which is pivoted to the face of the disc towards its
outer edge. The two opposite arins of the lever are connected to the rods which
actuate the inlet valves the ends of the rods striking against blocks sliding in guides
in the usual manner.
The rods themselves are pivoted to sliding blocks and have therefore a reciprocatory
and vertical oscillatory motion. The third arm of the lever is connected with and
operated by the expansion eccentric which imparts a rocking motion to it the effect of
which is to vary the motion of the rods actuating the valves. By means of this
combination of two eccentrics the rods may be caused to encounter the sliding blocks
very slowly or without shock thereby reducing the wear of the parts in contact. As
the actuating rod gradually rises during the whole of the valve opening stroke the
liberation of the valve slide block may take place at any point thereof which is not
possible in the usual Corliss gear where the liberation generally only takes place during
the opening half of the stroke. With this arrangement the selection of the lead angle is
therefore not restricted which is very desirable. The same gear may be readily adapted.
to other than Corliss valves.
In the accompanying drawings Figure 1 represents a side elevation of a steam
cylinder provided with the improved valve gear.
Figure 2 is a transverse section of the same and
Figure 3 is a diagramatic view indicating the position of the various parts corre-
sponding to the various phases of the eccentric.
A is the cylinder B and C are the steam Corliss valves D and E are the exhaust
valves F is the disc actuated at G by eccentric and rod in the usual manner.
In addition to the studs H and J for actuating the exhaust valves the disc F is
provided with a journal for the axis of a three armed lever K one arm L of which is
connected with the expansion eccentric.
Under the influence of the driving eccentric (which is represented in positions of
from 15° to 15° of its crank pin rotation in Figure 4) the pivots M N of the beam
will describe curves the inner halves of which (0 to 9) are in a characteristic steep and
slightly slanting direction. The phases of the rotation of the crank pin are denoted
by the figures 0-11 as also the corresponding positions of the expansion eccentric
which has a far greater stroke (twice to three times) than the driving eccentric and is
keyed on in a convenient angle to the driving eccentric.
•

page_text: The movement of the pivots M N of the beam K are transmitted to the striking
block R by rocking levers Q moving horizontally on their working centres or
fulcrums P the elongation PR of which forms the active catch of the expansion gear
the striking block actuating the Corliss valve in the usual manner by a slide and lever.
The active catch or striking block R encounters the passive one S at the commence-
ment of the stroke (i.e. when the valve is closed) when the pivots M or N are at about
the points 7, 8 or 9 of the inner side of their curve, with comparatively little speed
so that the shock and the wear are proportionally small. In the further course of
the stroke the active catch R pushes the passive one S at first slowly increasing the
speed as the valve begins to open. According to whether the passive catch S is
adjusted higher or lower by the governor in the slot of the guide by the guide pin T
the liberation of the catch S will take place sooner or later and the valve will be
closed by means of springs weights or otherwise.
As the active catch gradually rises during the whole of the valve opening stroke,
the liberation of the passive catch may also take place at any point of the opening stroke,
which is not possible in the usual Corliss gear where the liberation generally only takes
place during the opening half of the stroke of the active catch. With this arrangement
the selection of the lead angle is therefore not restricted which is very desirable the
exhaust valves being also actuated by the distributing eccentric.
The same gear may also be used for other than Corliss valves in which case the
spindles b and c must carry levers which lift the valves.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
In a variable expansion gear in which by the combination of two eccentric movements
with balance beam and connecting rods such a course is produced for the active catch
that it encounters the passive catch with but little speed and that the liberation is
possible during the whole time of the opening. The gearing mechanism consisting of
the disc (or lever F) operated by the distribution eccentric to which is pivoted a
balance beam such as M N operated by a second expansion eccentric in combination
with the rocking lever M-P-R whose working centre P travels in a straight line
substantially as and for the purpose specified.
Dated this 18th day of June 1887.