Year: 1888

page_text: A communication from EDMOND HENRY, of 2, Avenue des Tilluels, Montmartre, Paris,
France, Engineer.
I, EDMUND HUNT, of 87 St. Vincent Street, Glasgow, in the County of Lanark,
North Britain, Patent Agent, 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:—
This Invention has for its object the driving of twin screw propellers by means of a
single steam engine comprising one or more cylinders, and by means of improved
gearing which can be adjusted so as without reversing the engines to drive the two
screw propellers both in either the ahead or astern direction, or one in one direction
and the other in the opposite direction. The improved apparatus is more especially
designed for steam launches, or small steamers but is applicable for steamers of
various sizes.
In carrying out the Invention the crank shaft of the engine placed in the vertical
longitudinal centre plane of the boat has fixed on it a wheel or pulley having a rim
constructed for acting frictionally being either plain or grooved or covered with a
suitable frictional material. The two screw-propeller shafts have fixed on them similar
frictional wheels or pulleys and intermediate frictional wheels are employed together
with adjusting mechanism for causing the two shafts to be driven in the desired
directions.
The improved driving gear is susceptible of being variously arranged, and
convenient modifications are shown by way of example on two accompanying sheets
of explanatory drawings, Figure, 1, is a sectional end elevation of one modification,
and figure, 2, is a section as taken through one of the screw-propeller shafts and
through the axis of an intermediate pulley. Figures, 3, 4, and 5, are end elevations
showing three other modifications. In these drawings the same reference numerals
are used to mark the same or like parts wherever they are repeated.
In the modification shown in figures, 1, and 2, the crank shaft, 6, of the engine (the
engine not being shown) has fixed on it a frictional pulley, 7, and the two propeller
shafts, 8, 9, have fixed on them similar frictional pulleys, 10, 11. Each propeller
shaft, 8, 9, has its end carried in a bearing, 12, (shown as a thrust bearing in
figure, 2) which is externally cylindrical but eccentric to the shaft, and is fitted into a
cylindrical socket in the framing, 13. Hand levers, 14, are fixed on the eccentric
bearings of the two shafts, 8, 9; and by a slight movement of either lever the
respective pulley, 10, or 11, can be moved into driving contact with or out of contact
from the pulley, 7, on the engine shaft, 6. The very slight movement required for

page_text: this purpose does not necessitate any special provision, being made for it in the other
bearings of the shafts, 8, 9. Each propeller-shaft pulley, 10, 11, has always in
driving contact with it an intermediate frictional pulley, 15, 16, fixed on a short shaft
which is held in an eccentric bearing, 17. The two bearings, 17, are fitted in
rectangular blocks, 18, which are fitted in guides in the frame, 13, and are pressed by
springs, 19, so as to cause the intermediate pulleys, 15, 16, to bear sufficiently on the
propeller-shaft pulleys, 10, 11. In some cases the requisite driving pressure may be
obtained by means of screws or wedges without springs. On the eccentric bearings, 17,
of the intermediate pulleys, 15, 16, there are fixed rings, 20, formed with toothed
segments, 21, which gear with similar toothed segments on rings, 22, fixed on the
eccentric bearings, 12, of the propeller-shaft pulleys, 10, 11. The toothed segments, 21,
cause the eccentric bearings, 17, of the intermediate pulleys, 15, 16, to be always
moved oppositely from the eccentric bearings, 12, of the propeller-shaft pulleys, 10, 11;
so that when by means of a hand lever, 14, either propeller-shaft pulley, 10, or 11, is
moved sufficiently away from the engine-shaft pulley, 7, the intermediate pulley, 15,
or 16, is moved into driving contact with the engine-shaft pulley, 7, and as the
intermediate pulley remains in contact with the propeller-shaft pulley the consequence
is that the latter is driven in the opposite direction to that in which it would be driven
directly by the engine-shaft pulley. If the two screw propellers are one right-handed
and the other left-handed the two hand levers, 14, may be connected by a gab. link, 23,
for driving ahead or astern with both; and when it is wished to drive the two pro-
pellers differently the link, 23, may be lifted out of gear by a small lever and chain, 24,
to allow of the two hand levers being moved independently.
In the modification shown in figure, 3, the levers, 14, for moving the eccentric
bearings, 12, of the propeller shafts are moved by means of screw spindles, 25, with
hand wheels, 26. In other respects the gearing does not differ materially from what
is shown in figures, 1, and 2.
In the modification shown in figure, 4, two frictional pulleys, 7, 27, are placed in
driving contact with each other and one above the other in the middle. Either of
these pulleys, 7, 27, may be on the engine shaft the other being on a short shaft or on
a stud and driven by the one on the engine shaft. The propeller-shaft pulleys, 10, 11,
are placed so that with a small movement of their eccentric bearings, 12, either can be
placed in driving contact with either of the middle pulleys, 7, 27, so as to be driven
independently and in either direction.
The modification shown in figure, 5, differs from that shown in figure, 4, in having
intermediate pulleys, 28, 29, interposed between the middle pulleys, 7, 27, and the
propeller-shaft pulleys, 10, 11, these last being in ordinary bearings instead of
eccentric bearings. The direction of driving is, in the case of each propeller-shaft
pulley, 10, 11, determined by the high or low position of the respective intermediate
pulley, 28, or 29, and for the purpose of adjusting these intermediate pulleys as
required, their bearings are fitted in guides in the frame, 13, and are connected by
rods, 30, to screw hand wheels, 31.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed, I declare that what I
claim is :-
:
Driving gear for twin screw propellers and consisting of frictional wheels or pulleys
driven from a single engine and means for moving frictional wheels or pulleys on the
propeller shafts, or intermediate frictional wheels or pulleys into or out of driving
contact, the parts being arranged and operating substantially in the manner and for:
the purposes hereinbefore described.
: Dated this Twenty-fourth day of January 1888.