Improver ents in and relating to the Manufacture and Design of Screw Propellers.
Year: 1898

page_text: Date of Application, 28th Mar., 1898
Complete Specification Left, 24th Dec., 1898- Accepted, 28th Jan., 1899
PROVISIONAL SPECIFICATION.
Improver ents in and relating to the Manufacture and Design of
Screw Propellers.
J. EDWARD JOSEPH CURTIN, of 6. Saint Ronan's Avenue, Redland, Bristol,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in the design and manufacture of screw
propellers, and for this purpose I make the boss of such propellers preferably of
forged or cast steel, and upon such boss I cast or form at suitable angles longi-
tudinal ridges or projections, one for each blade of the propeller. In such longi-
tudinal ridges or projections I cast or cut by machine, a slot of the size and shape
required for receiving the bottom ends of the blades. These blades I preferably
form of rolled or forged plates of iron steel or metal of any kind, shaped to any
angle required. The bottom ends of such blades I fit into the ridges or projec-
tions on the boss and secure the same with bolts and nuts passing through the
ridges or projections and the blades. I may also make the boss and blades of such
propellers of cast iron or metal of any kind and I may secure the blades in the
ridges or projections on the boss with keys or wedges of any shape with or without
the aid of bolts and nuts. The boss and blades of such propeller may also be
galvanized or coated with metal of any kind by electro-deposition or otherwise.
Dated this 25th day of March 1898.
EDWARD JOSEPH OURTIN.
Improvements in and relating to the Manufacture and Design of
Screw Propellers.
I, EDWARD JOSEPH CURTIN, of 6, St. Ronan's Avenue, Redland, Bristol,
Engineer, do hereby declare the nature of this invention, and in what manner the
same is to he performed, to be particularly described and ascertained in and by
the following statement:-
This invention relates to screw propellers. According to this invention the pro-
peller boss is grooved longitudinally and into the grooves thus provided the butts
or inner ends of the blades are received. After the blades have been fitted into the
grooves they the blades-are secured by bolts, rivets, cotters or keys. The blades
have no segmental or other flanges at the root, and, consequently, when unshipped
from the boss, they are adapted to be stowed away in less space than blades not
so made.
Referring to the accompanying drawing. Fig. I represents, in side view, and

page_text: Fig. 2 in vertical section, a screw propeller having blades a and boss b made and
fitted in accordance with this invention. The boss b has grooves either cast or cut
in it. There are as many grooves as blades. Into the grooves are inserted the
inner or butt ends of the blades a. After insertion, the blades a are secured in
the boss by bolts e passed through the boss and through the blades. The nuts of
the bolts care preferably countersunk into the boss.
C
The boss is not necessarily triangular in section, as shown in the drawing. It
may be round or otherwise suitably shaped. Instead of being secured in the boss b
by bolts such as c, the blades a may be secured by keys, cotters, wedges or the like.
The blades are readily attached to and detached from the boss, and, having no
segmental or other shaped flanges or projections at the base, require less space for
stowing or storage than blades not so made. Hence the carriage of spare blades
is made more practicable.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
A screw propeller having a grooved boss, and blades with plain or unflanged
butts or inner ends fitting into the grooves in the boss, and bolts, keys, wedges,
cotters or the like securing to the boss the blades when in place, substantially as
hereinabove described.
Dated this 92nd day of Decumben. 1808
NICHOLAS WATTS.
Chartered Patent Agent, Bristol..