AN IMPROVED SYSTEM OF SCREW PROPELLER AND RUDDER, FACILITATING THE EVOLUTIONS OF VESSELS AND THE FITTING ON BOARD
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by William Edward Gedge at the Office
of the Commissioners of Patents on the 30th January 1880. A communi-
cation from abroad by Louis Ernest Chagrot, of Mende (Lozère), 'France,
Commandant de Gendarmerie.
WILLIAM EDWARD GEDGE, of No. 11, Wellington Street, Strand, London, in the
County of Middlesex, Patent Agent. "AN IMPROVED SYSTEM OF SCREW
PROPELLER AND RUDDER, FACILITATING THE EVOLUTIONS OF VESSELS AND THE
FITTING ON BOARD." A communication from abroad by Louis Ernest Chagrot, of
Mende (Lozère), France, Commandant de Gendarmerie.
"
The apparatus, the subject of this Invention, is an application of the mechanism
known as "Hooke's or the universal joint. It may be made of iron and steel or of
bronze and copper; in this latter case the screw propeller, the vertical bolt,
the cross-bar, and its axles, pivots, or pins, and the screw-keys are of bronze; the
upper and lower faces or surfaces of the seat bed or recess of the cross -bar are
provided with a bronze plate rolled according to the process used for the
"Uchatius" (Austrian) guns, the corresponding faces or surfaces of the cross-bar
being rolled in a similar manner.
The sphere which carries the screw will be forged with the shaft, and there will
be a small shaft fixed in the sternpost and connected with the intermediate shaft
by a T piece or a hexagonal joint or clutch. It will thus be easy to throw the
screw out of gear or let it run free. The clutch or joint will be strengthened
at the sternpost and at the junction of the two shafts to resist lateral pressures.
Upon the accompanying two Sheets of Drawing forming part of this Provisional
Specification,-
Fig. 1 (Sheet 1) represents a vertical section of the sphere which carries the
screw propeller; Figure 2 is a vertical section of the screw, the sphere being
fully shown; and Figures 3 and 4, horizontal sections of the system, the screw
in Fig. 4 being at an angle of 40 degrees to the longitudinal axis of the vessel.
A is the screwshaft; B, the sphere, in the axis of which there is a bolt C screwed
at its end and held by the screw -key C'. Perpendicularly to the axis of the bolt C
a seat, recess, or bed D is made to receive the crossbar E, which is held by the bolt C.
A solid triangular piece is left at the back of the seat D to connect this part of the
sphere and strengthen it. Part of the cross-bar is so made as to replace exactly
the slice taken from the sphere to form the seat D. A groove at E extending to the
axles or pivots contains a greased leather, which prevents the passage of the water.
The screws may be replaced by keys, and the seat D may be formed in the
entire length of the sphere, the bolt C will then have a strong head set or sunk
in the sphere, and will be fixed at the other end by a strong key or cottar.
The cross-bar carries on each side an axle or pin, screwed and held by the screw-
key V.
These axles or pins and the point H of the screw propeller secure this
latter in position on the sphere.

page_text: The interior of the
G is the boss or nave of the screw propeller; J, the blades.
boss is firstly conical, then cylindrical with a diameter equal to that of the sphere,
and terminates with a spherical cap which fits on to the sphere.
A seat or bed is made in the conical part to receive a copper ring I, having
The outer edge
underneath a groove or recess which holds an india-rubber tube.
of this ring holds the boss or nave on the sphere. The india-rubber, if it does not
keep out the water at any rate prevents any of the bodies which it holds in
The inside of the boss or nave will
suspension from entering into the mechanism.
not be completely water-tight, a little water will be allowed to enter for lubrication
and almost entirely to do away with friction.
In working, the sphere carries with it the bolt C and the crossbar E, the axles,
pivots, or pins of which in their turn carry with them the screw-propeller which,
held by its pivot H, revolves in the same axis as the shaft.
When the screw-propeller works forming a horizontal angle with the shaft,
the mechanism acts as in the direct working, but the crossbar oscillates around
the bolt C and insures the rotation of the boss or nave around the new axis which
is always cutting the longitudinal axis in the centre of the sphere.
The maximum angle to be given is 40 degrees, beyond that frictions are produced
in the mechanism which cause the axles or pins to wear. This angle is also sufficient
for the rapidity of the evolutions.
If an angle of 35° instead of 40 be held sufficient, the ring I, instead of being
oblique, will be perpendicular to the axis of the sphere. This will avoid the basin
or cup formed by this ring, which checks the working and producing an agitation
of bubbling up of the water.
The screw-propeller is worked like a rudder with a wheel, tiller-ropes or tackle,
and a tiller, or by the aid of a "servo-motem." It works with the rudder when
under steam, and is thrown out of gear therefrom when under sail only.
propeller shown on the Drawing is of a diameter of 5m. 80, it may have 3 or 4
blades.
The
In Sheet II., Fig. 1 is a vertical section shown showing the arrangement or
fitting of the screw and of the tillers; Fig. 2, the ordinary tillers seen from above,
and governing to an angle of 40°, Fig. 3 the fighting-tiller seen from above and
governing at the same angle. K, fixed frame firmly fastened to the vessel; L,
movable frame receiving the pivot H of the screw propeller, having its lower
pivot fixed on the keel and its upper one at the end of the fixed frame. A square
at the end of the pin O causes the movable frame to turn when actuated by the
tiller ropes or the "servo-motem." M is the rudder, N, its pin, P, its tiller, P¹, its
goose-neck and its sweep; Q, the tiller of the screw propeller, Q', its goose-neck and
its sweep. A connection R unites the two tillers; it has two studs R upon which
are stropped the pulleys of the tiller ropes D; this connection causes the two tillers
to turn parallely. T is the fighting-tiller of the rudder; U, that of the propeller.
They are joined by the connection X which has a rotary clutch or joint Y in which
the piston rod of the "servo-motem" is fixed.
When it is desired to travel under sail alone the tiller is put straight to the
bolt R which joins the connecting piece to the tiller of the propeller is removed,
the two squares Z which hold the connection by its tail in the axis of the tiller of
the rudder P are moved forward, finally, the bolt V which fixes the connecting
piece X to the fighting tiller T is removed and the forked piece S fixed to the
deck which, by means of its goose-neck Q¹, keeps the tiller of the propeller
straight, is allowed to fall. The screw propeller is then left free. To travel
under steam, the tillers are again connected by replacing the pieces in inverse
order.