IMPROVEMENTS IN THE EXPANSION GEAR OF STEAM ENGINES
Year: 1885

page_text: I HERMANN KÜHNE, Engineer, of 34 Great St Helens, in the City of London
in the County of Middlesex do hereby declare the nature of my invention for
IMPROVEMENTS IN THE EXPANSION GEAR OF STEAM ENGINES and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention consists in effecting the cut-off of the steam at any point of the
stroke in accordance with the load on the engine and thus to govern the admission
of steam and the speed of the engine, by regulating the travel of the slide valvo
by means of two Excentrics on the main or other suitable shaft of the engine,
hereafter called the shaft, one of the said excentrics being keyed on the shaft, the
other being free to turn round the first in a predetermined manner by a suitable
governor The governor is preferably but not necessarily arranged in the Fly wheel
in the following manner: Referring to the illustration: Two eyes in the spokes of
the fly wheel or other suitable arms fitted on the shaft carry round spindles E E¹
the said spindles projecting on both sides of the spokes, and to the Spindles are
keyed on one side the governor arms or Pendulums, which form two two armed
levers A B, A¹ B', which arms are provided at their longer ends A A¹ with adjust-
able governor balls or weights P P¹. The shorter ends B B¹ are suitably bent
towards the centre of the engine shaft and are at their extremity brought in
connection with suitable Pistons CC¹, sliding on a centre rod, the said Pistons
pressing on a coiled spring S from both sides, in such a manner that the centri-
fugal force of both governor balls P P¹ is counteracted by one and the same spring.
The said spring S is encased in a Cylinder K the cylinder being at its centre
pivotted by means of a boss in the centre of the shaft and free to turn therein.
The movement of the governor thus described will at varying speeds of the engine
be as follows: At a slow speed the governor arms A A¹ will be closed as drawn,
resting against suitable checks N N', the spring will be extended to the end of
its case pressing against the pistons C C, whose travel is at that point limited
by check screws and suitable pins on the spokes of the flywheel. When with
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increasing velocity of the engine the governor balls extend, the spring S will be
compressed from, both sides, and the spring together with its case will be slightly
turned round its pivot to follow the circular movement of the short governor
arms B B in such a manner that, whatever may be the angle of the governor arins
against their position in a state of rest, the pressure of the arms B B¹ is exerted
exactly, or very nearly so, through the centre of the engine shaft, and the
extending force of the spring is always exerted parrallel with the axis of the spring.
Two or more springs may be employed to exert the counteracting force against the
governor balls, always provided that they act in a similar manner as the one
spring S hitherto described. In order to make the governor pseudo-astatic, two
auxiliary weights or balls, fitted on short arms, Q Q¹, which arms are rigidly
connected with the two armed levers A B, A¹ B', are arranged in the manner as
drawn, which auxiliary weights during the first part of the opening of the
governor balls P P¹ assist the centrifugal force of the said governor balls P P¹,
while during the latter part of their opening tend to counteract that force The
inner ends of the said spindles at E E¹ are rigidly connected with two suitable
arms F F1, the outer ends of these arms being coupled to the outer excentric G by
means of eyes and bolts and connecting arms or other suitable means. It will be
understood that in this way the extending action of the governor balls P P¹ is
transferred proportionately to the outer excentric which determines the movement
of the slide valve, and, by selecting the proper angles, under which the inner
excentric is keyed on the shaft and under which the outer excentric is held in
relation to the inner one by the governor, the resulting throw of the two excentrics
will be automatically varied in such a manner as to determine the cut off of the
steam in the manner required.
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
1. The arrangement of a governor for varying automatically the Cut off in
Steam engines, substantially in the manner and for the purpose described.
2. In a Governor as described, the arrangement of one or more springs in a case,
the case being pivotted in the centre of the shaft, substantially in the manner and
for the purpose described.
3. The application of auxiliary governor weights, substantially in the manner
and for the purpose described.
London 24th day of Dasaraha 1005