IMPROVEMENTS IN PROPELLING AND STEERING VESSELS
Year: 1881

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for an
Invention of "IMPROVEMENTS IN PROPELLING AND STEERING VESSELS."
A communication from abroad by William H. Mallory, of the City of
Bridgeport, State of Connecticut, United States of America.
COMPLETE SPECIFICATION filed by the said Sydney Pitt at the Office of the
Commissioners of Patents on the 9th November 1881.
"IMPROVEMENTS IN
SYDNEY PITT, of Sutton, in the County of Surrey.
PROPELLING AND STEERING VESSELS." A communication from abroad by William
H. Mallory, of the City of Bridgeport, State of Connecticut, United States of
America.
It has been long known as a very desirable end to be accomplished to construct
a vessel which might be capable of being controlled both as to movement and
direction by its propeller wheel' or wheels. The idea of using the propeller as a
rudder to steer the vessel by changing its relation to the vessel is old in the art.
In the Specification of a previous Patent, No. 2277, dated the 1st day of July
1874, is shown a method of steering, stopping, and backing a vessel by varying
the plane of rotation of the propeller wheel with relation to the line of the vessel.
Owing however to the lateral thrust of the engine, a propeller wheel is constantly
tending to move laterally or around its vertical support in the direction in which
the vertical driving shaft revolves when arranged in such a forin as I have
described. It has been found necessary to apply a very great force in order to
control the position of the propeller wheel around its vertical axis, and my present
Invention is designed especially to overcome this difficulty by combining a double
propeller to form an apparatus which can be readily moved about its centre
support in both directions without the application of any considerable force; and
this is done primarily by driving two propeller wheels located opposite to each
other on the same central shaft in opposite directions by means of independent
connections extending down through said centre support or connection.
locating two oppositely revolving propellers in the manner as shown in the
Prise C71
By

page_text: Drawings, the tendency to slue the stern of the vessel is avoided, the tendency of
one of the wheels to throw the stern to the right being counteracted by the
tendency of the other wheel to throw it to the left, and by means of the peculiar
mechanism shown the double wheel can be revolved freely completely around its
central support.
The Invention will be readily understood from the accompanying Drawings,
in which Figure 1 represents a vertical section through the propeller driving
mechanisin taken longitudinally of the vessel; Figure 2, a view partly in section
and partly in perspective of portions of the apparatus; and Figure 3, a detailed
view of the method of connecting the propeller wheels to the central support, being
a section through Figure 1 on the line X, X.
The apparatus consists primarily of two propeller wheels A and B mounted
opposite to cach other on the same centre of support or casing F. This casing
rests in a socket K, and may be revolved around its vertical axis. The method
of supporting the propellor hubs and of attaching them to the centre casing F is
clearly shown in Figure 3, but any other practicable method may be used.
The construction shown in Figure 3 is as follows:-The thrust of the propeller
is received upon the thrust rings & upon the centre shafts a which are permanently
connected to the casing F. Parted or double sleeves b, b', are constructed to
exactly fit when united the shafts a provided with thrust rings d. The miter
gears L and M screw over and enclose the inner ends of these parted sleeves, and
the propeller hubs pass over and enclose their outer portions. When the propellers
are placed in position and keyed upon the sleeve in the usual way, the whole
forms a completed and solid mechanism not liable to become loose, and at the
same time affording sufficient bearing surface to receive the thrust of the propellers.
These propeller hubs are provided on their inner extremities with miter gears L
-and-M; by means of which they are rotated. The power to operate these propellers
is derived from the engino shaft E provided with miter gear G. This miter-
gear G gears into two other miter gears H and J, which miter gears are thereby
revolved in opposite directions. Connected with the miter gear J is the hollow
shaft C, provided at its lower extremity with miter gear P. This miter gear P
gears with the miter gear L attached to propeller A. The miter-gear H is attached
to a centre shaft D which stands in the axis of the revolving mechanism supporting
the propellers. Attached to the centre shaft D is the miter gear R, which gears
with the miter gear M which drives the propeller B. The position of the casing F
is determined by the worm screw S gearing in the worm wheel V. The worm
screw S is rotated by a shaft P.
The engine
The miter
The operation of the apparatus will now be readily understood.
being put in operation the shaft E operates the miter gears H and J.
gear H operates the shaft D, which rotates the propeller B by intermediate miter
gears R and M. The miter gear J operates the hollow shaft C and the propeller A
by means of the miter gears P and L. It will be observed that the two propellers A
and B are not set upon the same horizontal axis in order that the miter gears
connected with them may gear with the miter gears of the shaft and sleeve
respectively. If the gears were properly made it is plain that this division of the
engine thrust might be accomplished by having all four of the miter gears M, P,
L, and R, gear together when the same result might be accomplished, but owing
to the difficulties of this construction the construction shown in the Drawing is
preferred, which absolutely divides the thrust of the engine.
One of the difficulties interfering with the easy manipulation of this class of
self-steering propellers has been that the thrust or force of the engine necessarily
tended to twist the propeller case around its vertical axis, the engine force being
necessarily applied at a point more or less distant from the central vertical axis
of the propeller supporting mechanism. The principal object of this improvement
is to produce an apparatus in which the lateral thrust of the engine or the tendency
to twist the propeller around its support will be counteracted. This force has to
be ultimately met and overcome by the apparatus which is used to hold the

page_text: propellers in position or to alter their position, and consequently a great strain is
necessarily thrown upon what we may call the steering mechanism of the propeller.
By the arrangement shown this strain is entirely removed from the steering
mechanism, and this is accomplished by dividing the thrust of the engine as
communicated through the gears into two equal and opposite forces which counteract
cach other in their resultant effect upon the propeller and upon the steering
mechanism of the propeller. Supposing the apparatus to be operated in the
direction shown by the arrow in Figure 2, the tendency of the engine will be to
throw the forward end of the miter gear H to the right and the forward end of
the miter gear J to the left. Through the shaft D and hollow shaft C this force
will be communicated to the miter gears R and P. In the position shown in
Figure 3 the tendency of the miter gear P will be to throw the miter gear L to
the left, and thereby to twist the front of the casing in the direction shown by
the arrow y, while the tendency of the miter gear R operating upon the miter
gear M will be to twist the miter gear M to the right, and therefore to twist the
casing in the direction shown by the arrow y'; consequently the casing being
acted upon by two equal and opposite forces tending to twist it around its centre
in opposite directions can be, so far as these forces are concerned, freely moved
into any position. It will also be seen that by the construction of this apparatus
the double screws can be rotated completely around their axis of support.
position of the casing is readily determined by means of the worm wheel and
gear S, V, as before described. By this arrangement the double propeller can be
readily swung completely around its axis in either direction, and the vessel can
be instantly steered, stopped, or reversed. This Invention is particularly applicable
to torpedo boats, launches, and other war vessels, but may be used in combination
with any steam propelling vessel.
The
What I claim as the Invention, and desire to secure by Letters Patent is,-
First. The combination of the two propellers mounted upon a vertical frame or
support, and adapted to be swung completely around horizontally, with shafts or
their equivalents connected independently with each of said propellers, and con-
necting with the motive power of the vessel for the purpose of operating said
propellers in opposite directions, substantially as described.
Second. In a propelling apparatus provided with two propellers mounted upon
a frame revolving at the stern of a vessel, independent shafts or their equivalents
connecting the propellers and the driving apparatus to drive cach propeller
independently of the other and in an opposite direction, substantially as set forth.
Third. The combination of the two propellers mounted upon a vertical frame or
support, and adapted to bo swung completely around horizontally with shafts or
their equivalents connected independently with each of said propellers and passing
into the vessel for the purpose of operating said propellers in opposite directions,
substantially as described.
Fourth. The combination of two independently driven propellers mounted
opposite to each other upon the same vertical shaft with mechanism by which said
shaft may be rotated entirely around its contre substantially as described.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand
and seal, this Twenty second day of September, in the year of our Lord
One thousand eight hundred and eighty one.
SYDNEY PITT, (L.S.)