An Improved Construction of the Blades of Screw Propellers.
Year: 1887

page_text: Date of Application, 21st Jan., 1887
Complete Left, 21st Oct., 1887
Complete Accepted, 22nd Nov., 1887
PROVISIONAL SPECIFICATION,
An Improved Construction of the Blades of Screw Propellers.
I. JOHN EDDON REANEY, of No. 34 Leadenhall Street, in the City of London, E.C.,
Manufacturer. do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved construction of the blades of screw propellers
and is intended to obviate the loss which according to the present methods of
construction may be entailed by one of the blades turning out to be a defective casting.
In carrying my invention into effect, I make the skin of the propeller blade in two
parts which are severally produced, preferably by rolling during which process the
necessary pitch is given to them. I do not confine myself to rolling the skins
inasmuch as the particular grain or nature of the metal to be used may render the
selection of some other well known method of shaping metals preferable.
The junction of the two skins may be effected in any convenient way, as by rivetting
along the edges, and guarding the double edges by a coping strip which would present
a sharp edge to the water and make continuous surface with the blade.
The junction of the blade with the boss is effected by means of bolts and holding
rings or plates, or their equivalent. The skins of the blade are bent right and left and
the surface of the boss shaped to receive them. The skins are thickened gradually
and considerably where they contact with the propeller boss to enable them to
successfully resist the shearing strains which would be felt along these lines.
Dated this 21st day of January 1887
PHILLIPS & LEIGH,
Agents for the Applicant.

page_text: I, JOHN EDDON REANEY, of No. 34, Leadenhall Street, in the City of London,
E.C., Manufacturer, do hereby declaro 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 an improved construction of the blades of screw propellers.
It has hitherto been the practice to produce the blades of screw propellers by casting
them, and this method of making thein has been attended with the following sources
of loss and inconvenience.
1. In spite of careful melting and pouring, blow holes and other blemishes have
constantly forined in the casting, to the extent of rendering it worthless for the purpose
for which it was cast and reducing its value to that of scrap inetal.
2. Cast blades have necessarily been made solid partly for the sake of securing the
necessary degree of rigidity, and parily because the production of a hollow blade by
casting is practically impossible. The making of them solid has entailed the presence
of a weight of metal which is excessive in view of my present invention.
3. The considerable weight of a cast propeller has practically interdicted the use
in this branch of manufacture several known bronzes and alloys in spite of the
practical advantages derivable from density capacity for resisting shearing and torsional
strains, and corrosion, because of their high price as compared with other and less
durable alloys.
Now, according to my invention 1 make the skin of the blade in two halves, which
are after they have been bent to the desired pitch are carefully united along their
edges. The blade is then bolted to the boss in any convenient way.
I do not confine myself to any particular method of imparting the proper pitch to
the half blade, but I find that a process of pressing them between dies yields
satisfactory results.
The half blades may be made much thicker at their root than at their tip and
for this purpose I make use of eccentric rollers.
The necessary union of the two half blaules along their elges may he effected by
brazing, burning, or rivetting, and there may be incorporated with them along their
edge a coping strip, or an equivalent frame of the proper pitch and size may be made
in one piece with the boss.
For the purpose of effecting a proper junction between blades made as above
described and the boss 1 may form strong flanges of the necessary thickness on the
root of each half blade by which the blade can be bolted to the boss, or suitable clamps
may be used.
Additional plates may be used between the root and flange on the one side, and
the boss on the other, or a metal tree projecting from the boss may be led up the
cavity of a blade, the tops of its branches being in touch with the inner surfaces of
said blade.

page_text: In order that my invention and the means by which the same is to be carried into
practical effect may be thoroughly understood i will now describe the same in detail
reference being had to the accompanying figures which are to be taken as part of this
specification and read therewith.
Fig. 1 is a part sectional front elevation of a four-blade propeller illustrating a
method of attaching blades made according to my invention to the boss.
Fig. 2 is a sectional side elevation corresponding with Fig. 1.
Figs. 3 and 4 are sectional elevations illustrating two methods of strengthening the
roots of propeller blades.
Fig. 5 is a front elevation of a blade made by rivetting the half blades upon a frame
formed in one piece with the boss.
Fig. 6 is a plan corresponding therewith.
Fig. 7 is a front elevation of a blade.
Fig. 8 is a plan corresponding therewith.
Fig. 9 is a side elevation illustrating a method of clamping two blades to a boss.
Figs. 10 to 13 are detail sectional elevations illustrating different methods of effecting
a union between two half blades along their edges.
The metals I make use of for the manufacture of the metal plates the union of which
constitute the blades of my invention are iron steel bronze or other metallic alloy
although I wish it to be distinctly understood that I do not confine myself to any one
in particular, inasmuch as my improved method of making propeller blades allows me
a larger range of metals to select from without be it said overstepping the limits of
economical production than has hitherto been at the command of the manufacturer.
Referring to Figs. 1 and 2, a, a, are a pair of half blades. They are rolled taper
from their roots to their tips, and have Hanges b, b, formed upon them of a shape
adapted to bed down truly upon the boss c, upon which extensions c³, one to each
blade, are formed of a suitable cross section to accurately fill the throat of the blade.
The union between the edges of the two half blades a is shewn as effected by the
insertion of a strip a' rebated to receive the edges of the half blades to which it may
be brazed or otherwise amalgamated therewith; and the respective surfaces of which
ii continues till they meet in an edge formed on it.
The cavity of a blade may be filled with Val de Travers cement or other suitable
substance.
I provide clamps d of a suitable contour to bed down upon the flanges b and the
boss c and up against the roots of the blades and pass screw bolts e through the several
parts in proper number for the purpose of uniting boss clamps and blade into
practically a solid piece. The half blades may be made as thick at their roots as may
be desired and then connected to the boss in the ordinary manner.
Referring to Fig. 3, the half blades a, a, are of equal thickness throughout, their
union along their outer edge being effected by burning or analogous process.
F is a packing piece adapted by means of a cavity and snugs and corresponding
ridge and recesses on the boss to fit the latter without the risk of moving along
the same.
The outer surface of the packing piece is gradually sloped and returned towards the
boss, and the flanges of the half blades shaped to correspond therewith.
A series of strengthening plates y is inserted between the packing piece and each
balf blade. The plates of each series vary in length after the manner of the plates of
a waggon spring, the longest being next the half blade and the shortest next the packing
piece.
Bolts are passed through the respective half blades and the series of strengthening
plates; the blade is held to the packing piece by bolts h¹ and further bolts /² are
provided for fixing the blades to the boss.
Referring to Fig. 4 the plates 9 of Fig. 3 are replaced by a metal tree 1
independently bolted to the packing piece F. It is continued up the cavity of the
blade, its branches being in touch with the blades. The method of fixing a blad
nade as illustrated in Fig. 4 is the same as illustrated in the previous figure and
described therewith.

page_text: Referring to Figs. 5 and 6 J is a frame of the same form as the edge of a blade
formed in one piece with the boss. It is rebated in the same way as the strip a
illustrated in Fig. 2 and described therewith. The half blades are rivetted to the inner
tongue of the frame.
The bottom of the frame is extended into a concave j of suitable thickness from
which projects two stout snugs j¹ both of them adapted to bed close upon and into the
boss to which the concave may be clamped or bolted in any convenient way e.g., as
illustrated in Figures 1 or 3.
Referring to Figs. 7 and 8, the blade illustrated differs only from that illustrated in
the two figures last described, in having the union between two half blades effected by
brazing.
Fig. 9 is a side elevation illustrating the method of clamping and bolting shewn in
detail in Fig. 1.
Fig. 10 illustrates the union of two half blades by a coping strip, rivetted thereupon.
Fig. 11 illustrates the union of two half blades along their edge by brazing.
According to the method illustrated in Figure 12 the half blades are rivetted and the
coping strip is afterwards brazed to the blade.
Fig. 13 illustrates the union of two half blades by means of a rebated strip and
rivets.
It is evident that the methods of effecting the aforesaid union may be varied according
to circumstances, without departing from my invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The combination of two metal plates properly shaped and pitched for the purpose
of producing a propeller blade, and adapted to be fixed upon the boss of a screw
propeller.
2. The combination of two half-blades; a metal strip adapted to make continuous
surface with them along their edge; and strengthening plates and flanges;
substantially as described with reference to the accompanying figures.
3. The combination of two half-blades united along their outer edges; flanges
adapted to bed down upon the boss: extensions of the boss entering the cavity of the
blade; and cramps; substantially as described with reference to the accompanying
figures.
Dated this 21st day of October 1887