Improvements in and connected with the Propelling Apparatus of Ships.
Year: 1893

page_text: Date of Application, 12th Sept., 1893--Accepted, 7th July, 1894
COMPLETE SPECIFICATION.
Improvements in and connected with the Propelling Apparatus of
Ships.
I, CHARLES CASMAN of Wilsele near Louvain in the Kingdom of Belgium,
Watchmaker, 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 that class of ships' propellers which act by thrusts, and
has for its object to minimise the disadvantages accompanying the opening and
closing of the propeller blades and to provide a reversing device by means of which
the vessel may be backed without stopping the reciprocating driving shaft.
The invention is shown in the accompanying drawings, in which,
Figures 1 and 2 are side elevations of the propeller with its parts in the positions
they occupy when the ship is moving ahead and astern respectively.
Figure 3 is a front view of Figure 2.
Figures 1 and 2 are diagrammatic views in plan illustrating the operation of
the propeller when the ship is moving ahead and astern respectively.
Figure 4 is a side elevation of the device for reversing the motion of the ship.
Figures 5, 6, 7 and 8 show details of Figure 4.
In propellers of this class hitherto, the blades were supported by hinges fixed on
their inner edges. This invention consists in fixing the hinges near the centre of
the blade, but slightly towards the inner edge as shown in Figure 3, in which are
the hinges and F the movable blades, the hinges being secured to arms P rigidly
connected with the shaft A (Figures 1 and 2). By this means the force obtained
for the opening or closing of the blades caused by the resistance of the water,
when the propeller is moving forwards or backwards, is diminished, as the action of
the pressure of the water will then no longer correspond to the full surface of the
blade z plus r, but only to the surface z minus x, so that by this alteration, the
blade F becomes a double lever and the pressure on the surface acts against that
on the surface z. The closer the axes of the hinges lie to the inner edge of the
blade F, the greater will be the force obtained for opening or closing the blades,
and the closer they lie to the centre of the blades, the less will be such force. This
alteration in the position of the hinges has no effect on the action of the blades
during the thrust for driving the ship ahead or astern, as then both parts & and z
act on the water in the same direction.
The invention further consists in a device to enable the motion of the ship to be
reversed without stopping the reciprocation of the driving shaft. This consists in
having a second shaft B movably arranged and packed within the shaft A, which
latter is made hollow for the purpose, the shaft B projecting at both ends from the
hollow shaft. A boss or collar C is rigidly attached to the shaft B, on the
end which projects outside the ship, and this boss or collar C is provided with
arms D and E which support the blades F when the latter bear against them whilst
the shaft is making a propelling thrust as hereinafter described.
In order to reverse the motion of the ship the shaft B must be rotated about
90 degrees so that the arms D are brought from a vertical into a horizontal
position, whilst the arms E assume a vertical position, or vice versa.
This may be
effected by means of the device shown in Figures 4, 5, 6, and 7 which consists of
a toothed wheel H firmly keyed on the inner shaft B, and a sector consisting of
bars j, cheeks K and shaft M engaging with the teeth on H. By pulling a
lever S attached to the shaft M, the inner shaft B may be rotated about 90 degrees,
whilst by throwing back the said lever the shaft B may be again returned to its

page_text: former position. These arms D and E being rigidly connected to the shaft B will
turn with the latter in order to take up different positions as above described.
The boss C of the shaft B is also provided, in addition to the arms D and E,
with arms or projections u which have for their object to prevent the outer edges of
the blades or wings F coming too close to one another on the return stroke of the
shaft, which would cause the rear instead of the front faces of the blades to act on
the water on the succeeding thrust, whereby the effect of the thrust would be
diminished owing to the acute angular position of the blades F to the direction of
the stroke. These arms u, on the return stroke of the shaft, act as stops for the
blades, and prevent the outer edges of the latter from moving too close to one
another, the blades bearing against the ends of said arms u when they have closed
to such a position that the distance. between their outer edges is only a little
greater than the distance between the axes of the hinges 1 l.
The mode of action is as follows:-
When the ship is to move ahead, the arms D and E are turned into the position
in which the former are vertical and the latter horizontal (Figures 1 and 1^) by
pulling over the lever S, and the two shafts A and B are together set into a
reciprocating motion from the engine by means of a forked connecting rod attached
to the pins O. During each outward stroke of the propeller, the hinged blades F
are thrown open by the resistance of the water and are supported in this position
by the arms E against which they bear, whilst on the return stroke the blades are
closed by the resistance of the water so that they bear against the arms u: The
ship is thereby propelled ahead.
When it is desired to reverse the motion of the ship, the lever S is thrown back,
thus turning the arms D and E into the position in which the former are horizontal
whilst the latter are vertical (Figures 2 and 24), this being readily effected without
The blades F will now bear
stopping the reciprocation of the propeller shaft.
against the arms D instead of E as before and will therefore assume their open
position during the inward pull of the shaft, whilst on the outward stroke, the
blades will close against the ends of the arms u. The ship will therefore be now
propelled astern.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In ships' propelling apparatus acting by thrusts, arranging the hinges / on the
blades F in such a way that their axes fall in the inner half of the said blades so
that they form double levers with uneven sections a and z, for the object of
diminishing the inconvenience caused by the opening and closing of the blades.
2. In the device described in Claim 1, the arrangement of inner and outer arms
or supports E and D on a shaft B which is movably arranged in the thrust
imparting shaft A, for the object of effecting the reversal of the ship from
forwards to backwards or vice versa.
3. In the device described in Claim 2, a gearing consisting of a spur wheel H
and sector wheel K M, for the object of revolving the inner shaft during its back
and forward motion.
Dated this 11th day of September 1893.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.