Improvements in the Design and Method of Constructing Screw Propellers, and Means of Protecting Propellers or Screws from Pitting or Corrosion
Year: 1895

page_text: Date of Application, 6th May, 1895
Complete Specification Left, 25th Feb, 1896-Accepted, 18th Apr,
1896
PROVISIONAL SPECIFICATION
Improvements in the Design and Method of Constructing Screw
Propellers, and Means of Protecting Propellers or Screws from
Pitting or Corrosion
1 PATRICK JOSEPH MCCABE Engineer 6 Summer Hill, Sunderland County
of Durham England do hereby declare the nature of this invention to be as
follows
-
The object of my present invention is to secure an improved method of con-
structing screw propellers and to protect them from the action of water, which
causes pitting or corrosion
First I make a propellor or screw with two or more blades or portions of the
belix I make the centre or hub of a propellor in one piece or part, it may be in
steel, malleable iron, cast iron, brass, or bronze, or other mixture The centre or
hub is made with arms, in accordance with the number of blades or portions of the
helix or screw required These blades may be made of steel, malleable iron, cast
iron, brass, bronze or other suitable material I make them in sheets or plates, of
the material mentioned, in sizes or shapes and in number as I may think necessary
or required for the power to be developed
The sheets or plates are either bolted or rivetted or welded at the edges, to form
one complete blade I also make the propeller blades in one piece forged or of cast
material with suitable flanges or with bosses on them, to suit the round arms
Each blade in whichever way it may be made is secured to the arms, or to the
centie or hub with bolts or by cottars, or by the flanges
The arms which are
solid with the centre, may be flat, round or oblong & tapered, as may be required
I arrange from the flanges on the blades indicators to shew the pitches the
blades are set to
Second I cause to be deposited or cast on, over each blade or partially so, a
covering of copper brass bronze platinum aluminium, mixtures of zinc & tin
aluminum, mixtures of zinc & tin or other metals, which resist the pitting or
corrosion of propeller blades
Dated this Sixth day of May 1895
Improvements in the Design and Method of Constructing Screw
Propellers, and Means of Protecting Propellers or Screws from
Pitting or Corrosion
1, PATRICK JOSEPH MCCABE Engineer 6 Summerhill Sunderland County of
Durham England, 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
-
The object of my present invention is to secure an improved method of con-
structing screw propellers, to strengthen the blades of propellers, and to protect the

page_text: blades from the action of water on them preventing corrosion or pitting of th
metals of the blades or the deterioration of them
First I make a propeller or screw with two or more blades, or portions of
helix I make the centre boss or hub of a propeller in one solid piece or part, o
either steel, malleable iron, cast iron, brass or bronze or other metals The
centre boss is made with arms forged or cast on with it These arms are to
have a section and length extending out from the centre boss, in accordance with
the requirements for the strengthening of the blades
Each arm is provided with a nut and screw at the top, or point of arm to fasten
or screw the blade to the centre boss, or each blade may be fastened to the centie
boss by a strong cotter passing through the blade and arm, wedging the blade to
the centre boss
I make the blades either of steel malleable iron, cast iron, brass, bronze, o
other suitable metal I make the blades solid by rasting them from either of the
metals mentioned or I forge them out of any of the same mentioned metals which
may be suitable to forge
I also make propeller blades in sheets or plates of these metals in sizes and shapes
and number as I may think necessary or required for the power to be developed
The sheets of metals forming blades are either bolted together, or rivetted together,
or welded at the edges together
Each blade whether made solid or by plates fixed together have sleeves formed
on them to receive the arm< I make them either round, square, oblong or other
suitable shape to suit the arms
Secondly I cause to be cast on each blade of a propeller a thin coating or
covering of either copper, brass, bronze, platinum, aluminium, or mixture of 7inc
& tin, or other metals able to resist the action of the water, which causes corrosion
or pitting or any deterioration whatever, or I cause to be deposited on the blades
a thin film or coating of the before mentioned metals, enough to give protection, to
prevent any corrosion pitting or deterioration by electricity or otherwise
In order to enable my invention to be fully understood, I shall proceed to
describe the same by reference to the drawings
Fig 1 shews a screw with 4 blades in position
Fig 2 elevation of blade and part section at arm
Fig 3 sectional elevation shewing arm A, and nut G in position
Fig 4 plan view of a propeller
Fig 5 sectional elevation of a blade, with cotter hole through arm and blade
A represents the arm
ARCARGIL
the centre boss
the propeller shaft
the nut on shaft to keep propeller on
propeller blades
B
"
"
"
"
"
"
"
cotter to wedge down blade
"
the nut on arm to screw down blade
studs to screw down blade
section of blade through arm
Having now particularly described & ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim 18,
First An improved method of giving great strength to, and fixing the blades of
propellers, or portions of the helix to the centre boss or hub by arms to which the
blades are fixed, the arms being forged or cast solid with the centre boss, and
forming part of it
Second An improved method of making or constructing propeller blades or
portions of a helix by the fixing or fastening of iron, steel, or other suitable
materials in plates fixed together to form a blade of a propeller, by the welding of

page_text: these plates together or by rivetting or bolting the plates together and thus
forming a propeller blade
Third The improved method of securing or fixing propeller blades to the boss
or hub, by nut and screw on the end of the arm, or by a cotter put through the
blade and arm
Fourth An improved method of protecting propeller blades from corrosion,
pitting or deterioration caused by the action or impact of water on them, in casting
on the surface of the blade which is to be protected, a thin coating of copper, brass
bronze, or mixture zinc, tin, copper &c, or by the depositing of those or other
suitable metals on the blades by electricity or otherwise
Dated this 25th day of February 1896
PATRICK JOSEPH MCCABE