Improvements in Apparatus for Turning Large Steam Engines.
Year: 1888

page_text: Improvements in Apparatus for Turning Large Steam Engines.
I, ANDREW BETTS BROWN, of Rosebank Iron Works, Edinburgh, in the County of
Mid Lothian, North Britain, Engineer, do hereby declare the nature of this Invention
to be as follows, that is to say :-
My said Invention has for its object to provide improved apparatus for turning
large engines at times when the positions of their parts require to be changed whilst
they cannot themselves be worked..
In carrying out my Invention the shaft of the large engine has, as usual, a
wormwheel fixed on it to be acted on by a worm which can be moved along a shaft
which carries and turns it so as to be put into gear with the worm-wheel when
required. On the worm shaft there are fixed two square-toothed ratchet wheels, and
pawls for acting on these ratchet wheels are carried by two drums or disks which
are loose on the shaft, and each of which has fixed to or formed in the same piece
with a pinion. One pinion has gearing with it one side of a double rack, and the
other pinion is geared through an intermediate pinion with a pinion on a counter-
shaft, which countershaft has fast on it a pinion gearing with the other side of the
double rack. The double rack is connected to the piston of a motor cylinder arranged
to be worked by steam or by water under pressure. The pawls of the drums or
disks can be adjusted to act in either direction, and when they are adjusted for the
direction in which it is wished to turn the shaft of the large engines, the recipro-
cation of the double rack effects the desired movement. The arrangement of the
gearing is such that the pinions on the worm shaft rotate oppositely to each other
and alternately in opposite directions, the motion of each being communicated to the
worm shaft only in the direction for which the pawls are adjusted. The countershaft.
may be placed so that the pinion on it will be acted on by the same side of the rack
as the pinion on the worm shaft, in which case an intermediate pinion is not required.
A pump cylinder may be fitted in connection with the motor cylinder, to be worke
as a pump by the latter when convenient, and to be used as a regulator when the
D
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page_text: motor cylinder is being used to turn the large engines, in which latter case the
ordinary discharge of the pump will be closed and a by-pass valve will be opened
to allow water to pass backwards and forwards from one end of the pump cylinder
to the other, but at a speed depending on the adjustment of the by-pass valve."
Dated this Twenty-second day of February 1888.
EDMUND HUNT,
Applicant's Agent.
I, ANDREW BETTS BROWN, of Rosebank Iron Works, Edinburgh, in the County of
Mid Lothian, North Britain, 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, that is to say :-
My said Invention has for its object to provide improved apparatus for turning
large steam engines at times when the positions of their parts require to be changed
whilst they cannot themselves be worked.
My improved apparatus is shown on an accompanying sheet of explanatory
drawings, on which figure, 1, is an elevation, figure, 2, a horizontal section, and
figure, 3, a partial sectional elevation as at right angles to figure, 1, and squaring
with figure, 2. In these drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
In carrying out my Invention the shaft, 5, of the large engines bas as usual a
worm wheel, 6, fixed ou it to be acted on by a worm, 7, which can be moved along a
shaft, 8, which carries and turns it so as to be put into gear with the worm wheel when
required. On the worm shaft, 8, there are fixed two square-toothed ratcbot wheels, 9,
which are enclosed in drums, 10, and of which one is seen in figure, 1, and the other
in figure, 2. Pawls, 11, for acting on the ratchet wheels, 9, are carried by the
drums, 10, which are loose on the shaft, 8, and which have fixed to or formed in the
same piece with them pinions, 12, 13. One pinion, 12, has gearing with it one side
of a double rack, 14, and the other pinion, 13, is geared through an intermediate
pinion, 15, on a stud, 16, with a pinion, 17, on a counter shaft, 18, which counter
shaft has fast on it a pinion, 19, gearing with the other side of the double rack, 14.
The double rack, 14, is attached to the piston rod, 20, of a motor cylinder, 21, arranged
to be worked by steam (or it might be by water under pressure with a cylinder of
suitable size). The pawls, 11, of the drums, 10, can be adjusted to act in either
direction, and when they are adjusted for the direction in which it is wished to turn

page_text: the shaft of the large engines, the reciprocation of the double rack, 14, effects the
desired movement, each pinion, 12, 13, operating through the drums, 10, and
pawls, 11, on the shaft, 8, alternately, and each only when the rack is turning it in
the right direction. The pawls, 11, which are double, and of which, there are two
diametrically opposite each other fitted to each drum, 10, are fixed on spindles on
the outer ends of which there are small levers, 22. A link, 23, connecting the
levers, 22, of each diametric pair of pawls, 11, makes the pair work together; and a
spring is applied to a second arın on one of the levers, 22. The spring is a helical
compression spring contained in a box, 24, jointed to the rim of the drum, 10, and it
acts on an adjustable collar, on a rod, 25, jointed to the pawl lever, 22. In figure, 1,
the parts are shown in the middle position in which the pawls are inoperative; and to
make them act the arm of the pawl lever, 22, is turned outwards or inwards and the
collar on the rod, 25, is screwed to compress the spring.
The counter shaft (18) may be placed above the worm shaft (8) or otherwise so that
the pinion on it will be acted on by the same side of the rack (14) as the pinion on the
worm shaft, in which case an intermediate pinion is not required, the countershaft
being geared directly to one of the drums, 10, by pinions on it and on the drum such
pinions being a little larger than those acted on by the rack to allow the latter pinions
to be clear of each other.
A pump cylinder, 26, may be fitted in connection with the motor cylinder, 21, to be
worked as a pump by the latter when convenient, and to be used as a regulator when
the motor cylinder, 21, is being used to turn the large engines. In the latter case the
ordinary discharge of the pump will be closed and a by-pass valve, 27, will be opened
to allow water to pass backwards and forwards from one end of the pump cylinder to
the other, but at a speed depending on the adjustment of the by-pass valve.
The distribution valve or valves of the motor cylinder, 21, and their actuating gear
may be of any suitable kind such as is in use in direct-acting non-rotative steam
pumping apparatus.
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 :-
Combining and arranging parts of apparatus for turning large steam engines in
the improved manner substantially as herein before described and as shown in the
accompanying drawings.
Dated LTL
11000
.
EDMUND HUNT,
Applicant's Agent.