Improvements in Screw Propellers for Ships.
Year: 1895

page_text: Date of Application, 26th Oct., 1895
Complete Specification Left, 7th July, 1896-Accepted, 5th Sept., 1896
PROVISIONAL SPECIFICATION.
Improvements in Screw Propellers for Ships.
I, ALFRED BONNOTTE of 61 Rue de Lyon, Paris, in the Republic of France,
Engineer, do hereby declare the nature of my invention to be as follows:-
My invention relates to ships' screw propellers and consists in forming the
blades thereof in a manner which I will describe with reference to the accompanying
drawings:
-
Figures 1 and 2 are diagrams shewing the manner of generating a blade for a
propeller in which three blades are employed.
Figures 3 and 4 shew, in transverse section and in longitudinal elevation,
respectively, a segment of a propeller constructed with three blades and equal in
length to the pitch of the screw blades.
I take as an example for the purpose of describing the nature of my invention,
a propeller provided with three blades. As all the blades are identical with each
other the description of one will suffice.
The transverse section of each blade has the form of a thin solid figure of the
curved shape a. b. c. d. e. f. g, as shewn in Figure 1, which is concave in the
direction of motion of the propeller shewn by the arrow, and is helically arranged
around the axis X of a cylinder or boss h. i. j. k, the plane of the blade being
always normal to the axis and the arc of the circle d. e. coinciding with the
surface of the said boss. The point a of the blade describes the helical
curve a aa and the points c. d. e. f. describe the helical curves c¹¹c,
ddd, el ll lll, flfll fill respectively. The apparent contour of the
external surface of the blade is completed by the curved lines a¹ and all
which are obtained in a simple manner by the construction shewn by dotted lines
in Figures 1 and 2.
Figures 3 and 4 shew the construction of a propeller provided with three
blades, A1 A2 A3, shaped in the manner described. The bases, or feet, B¹ B² B³
of these blades may be secured to the boss (constituted by the sleeve D) by means
of screws C with heads sunk level with the bases, or projecting therefrom, or by
any other suitable means, the said sleeve being keyed, or wedged, or otherwise
suitably fixed, on the motor shaft E, of the propeller.
Although I have described my invention as applied to the construction of a
propeller having three blades, and equal in length to one pitch of the helix
formed by each blade, yet it is not limited to this number of blades, nor to the
length specified, as these may be modified without departing from my invention,
and the form, or curvature, of the blades in cross section, and the pitch, or
inclination, of the blades, may be varied.
The said propeller may be constructed in sections capable of fitting together
and of being mounted consecutively on the motor shaft E, according as it may be
found necessary for obtaining the desired strength.
Dated this 26th day of October 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, Loudon, W.C., Agents for the Applicant.

page_text: I, ALFRED BONNOTTE of 61 Rue de Lyon, Paris, in the Republic of France,
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 :-
My invention relates to ships' screw propellers, and consists in forming the
blades thereof in a manner which I will describe with reference to the accompanying
drawings:-
Figures 1 and 2 are diagrams shewing the manner of generating a blade for a
propeller in which three blades are employed.
Figures 3 and 4 shew, in transverse section, and in longitudinal elevation,
respectively, a segment of a propeller constructed with three blades and equal in
length to the pitch of the screw blades.
I take as an example for the purpose of describing the nature of my invention
a propeller provided with three blades. As all the blades are identical with each
other the description of oue will suffice.
The transverse section of each blade has the form of a thin solid figure of the
curved shape abcdefg as shewn in Figure 1, which is concave in the direction of
motion of the propeller shewn by the arrow and is helically arranged around the
axis X of a cylinder or boss hij k, the plane or transverse section and also the
inclination of the blade with respect to the axis being the same throughout and
the arc of the circle de coinciding with the surface of the said boss. The point a
of the blade, describes the helical curve a¹ all all and the points c d e f describe
the helical curves c¹ cc, d¹ d" d¹¹, el el elll, ƒ ƒ" fill respectively. The
apparent contour of the external surface of the blade is completed by the curved
lines a¹, and all which are obtained in a simple manuer by the construction
shewn by dotted lines in Figures 1 and 2.
Figures 3 and 4 shew the construction of a propeller provided with three
blades, A A A³, shaped in the manner described. The bases, or feet, B' B* B³,
of these blades may be secured to the boss (constituted by the sleeve D) by means
of screws C with heads sunk level with the bases, or projecting therefrom, or by
any other suitable means, the said sleeve being keyed, or wedged, or otherwise
suitably fixed, on the motor shaft E, of the propeller."
Although I have described my invention as applied to the construction of a
propeller having three blades, and equal in length to one pitch of the helix formed
by each blade, yet it is not limited to this number of blades, nor to the length
specified, as these may be modified without departing from my invention, and the
form, or curvature, of the blades in cross section and the pitch, or inclination, of
the blades, may be varied.
The said propeller may be constructed in sections capable of fitting together
and of being mounted consecutively on the motor shaft E, according as it may be
found necessary for obtaining the desired strength.
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. A screw propeller for ships each blade of which is formed of a thin solid
figure in transverse section of curved shape arranged helically round the axis of
the motor shaft the plane or transverse section and also the inclination of the
blade with respect to the axis being the same throughout substantially as described.
2. A screw propeller of the kind described in Claim I made in sections capable

page_text: of being fitted together and mounted consecutively on the motor shaft substantially
as and for the purpose hereinbefore described.
3. A screw propeller for ships made substantially as herein before described and
illustrated in the accompanying drawings.
Dated this 7th day of July 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields; London, W.C., Agents.