IMPROVEMENTS IN AND RELATING TO SCREW PROPELLERS FOR NAVIGABLE VESSELS to be as follows
Year: 1885

page_text: I, JOSEPH BELDUKE (in French "Bol duc") of San Francisco, California, United
States, America and care of A. C. Dick and Company of 9 Rumford Place,
Liverpool in the County of Lancaster, Blacksmith do hereby declare the nature
of my said invention for "IMPROVEMENTS IN AND RELATING TO SCREW PROPELLERS
FOR NAVIGABLE VESSELS to be as follows:-
"
My invention relates to a certain novel construction of screw propellers consisting
of radial blades or flukes, fixed to a hollow cylindrical hub or band that is secured
to the propelling shaft in such a manner that they are brought out into a solid
body of water outside of the converging water, or dead water as it is termed
immediately around the shaft, and are rendered much more effective in their
action.
The blade is made in an improved form and the cylindrical hub and the blades
so proportioned that a considerable part of the working surface of the blades
extends beyond the hub at front and rear and the length of the hub bears small
proportion to the length of the blades, and yet acts to properly hold, support, and
operate them. The cylindrical hub which carries the arms is preferably hollow
supported by two or more arms attached to a small internal hub by means of
which it is keyed or otherwise attached to the shaft by means of which it is
actuated..
The blades, two, but preferably three or more in number, are segments of a helix
of which the axis coincides with the axis of the hub that carries them.
The surface of the blade while being a segment of a helix is formed on straight
lines that are perpendicular to and radiate from the axis of the carrying hub or
cylinder.
.
It is of equal thickness above the base or bottom line, but at and along this
bottom line it curves outwardly and downwardly on both faces to form a web or
flange along its base from end to end.
This flange is then substantially at right angles to the surface of the blade and
gives the required strength and stiffness along the bottom of the blade where it
springs from the cylinder.
-
The front edge of the blade is made somewhat thinner than the principal portion
or body to give it a fin-like form especially at the lower edge and at the point also
where it is rounded off.

page_text: +
The base of the blade is placed diagonally across, and projects from a fastening
block which is preferably formed solidly with the blade and in one piece.
The ends of this block are made to take over and embrace the rim of the hub
and for that purpose it has dove-tail grooves in the ledges or projecting part, one
of which receives the front edge of the cylinder rim, while the other fits over a
projecting wedge shape portion provided, on the rear edge or opposite end of the
rim of the hub. When placed upon the rim and pressed forward the tapering
form of this projection serves to lock it firmly in position. Fastening bolts are
then passed through the blocks and through the rim of the hub beneath to secure
the blades.
I
:
In applying, or forming this fastening block, two modes of joining it and the
blade together may be employed according as may be desired to increase the speed
of the propeller or add to its power at the expense of its speed. One of these
forms consists in connecting the blocks and the bottom flange of the blade together
by means of a contracted neck portion, which springs from the face of the block in
a curve, and meets and joins the edge of the wheel or flange, thereby giving &
clearance or space between the flanges and the face of the block.
But by leaving out this neck or clearance beneath the blade and bringing the
flange directly down to the block, the block is practically made a widening and
extension of the flange, this construction brings the. blade closer to the cylinder
and thereby contributes to stiffness or reduces the spring of the blade.
If preferred the block may be secured to the cylinder by a wedge shaped tongue,
and a groove or mortice cut across the hub, and widened at the bottoin to give a
dovetailed form, the convex surface of the hub being finished off flat for a seat,
The underside of the block is provided with a tapering tongue or tenon to fit
the slot and this face of the block is made in a curve to fit the seat.
Bolt holes are made through the block and into the cylinder for fastening bolts.
In applying this propeller to a vessel where the well-room will not permit the
full length of blade to be used at both ends of the propeller hub its length is
reduced by removing a sufficient amount of the blade from one end of the hub,
either at the rear end of the blade next to the hub or at the tip. It will be
understood that where preferred the propeller blades and hub may be cast all in
one piece.
WM P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, and
323, High Holborn, London,
Patent Agents for the Applicant.

page_text: Improvements in and relating to Screw Propellers for Navigable
Vessels.
I JOSEPH BELDUKE (in French Bolduc) of City and County of San Francisco,
State of California, United States of America, Blacksmith, a citizen of the United
States at present in Liverpool in the County of Lancaster do hereby declare the
nature of the said invention for "IMPROVEMENTS IN AND RELATING TO SCREW
PROPELLERS FOR NAVIGABLE VESSELS" 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 a certain novel construction of screw propellers consisting
of radial blades or flukes fixed to a hollow cylindrical hub or band that is secured
to the propelling shaft in such a manner that they are brought out into a solid
body of water outside of the converging water or dead water as it is termed
immediately around the shaft and are rendered much more effective in their
action.
This present improvement consists first in an improved form of blade and the
manner of securing it to the Cylinder or hub-Secondly in proportioning the
Cylindrical hub and the blades so that a considerable part of the working surface
of the blades extends beyond the Cylinder at front and rear and the length of the
Cylinder bears small proportion to the length of the blades and yet acts to properly.
hold support and operate the blades And lastly in an improved form or construction
of helix blade and the means of securing it to the rim of the hub or cylindrical
band.
The following description fully explains the nature of my said improvements
and the manner in which I proceed to construct apply and use the said the.
accompanying drawing being referred to by figures and Letters as follows.
Figure 1 is an end elevation of my improved propeller removed from the shaft.
Figure 2 is an elevation in persceptive of the same.
Figure 3 is a plan or top view of figure 1.
Figure 4 is a section through the centre of one of the blades taken on the
line XX Figure 3.
Figure 5 is a top view of the Cylinder shewing the wedge shape projections on
the edge of the rim to hold the fastening block.
Figures 6 and 7 are detailed views shewing the manner in which I form the
blade and fastening block together without any neck or clearance between them.
Figure 8 is a front elevation of hub and blades shewing another method of
fastening them to the cylindrical hub..
Figure 9 is a front elevation of cylindrical hub shewing mortice or groove cut in
same for securing the blade.
Figure 10 is a view of underside of blade.
The blades A two three or more in number are segments of a helix of which the
axis coincides with the axis of the cylinder B that carries them.

page_text: They are of such length as compared with the Cylinder that a considerable.
portion of the surface of the front and rear projects beyond the Cylinder.
The improved manner of fastening the blades to the Cylinder as well as the form
of the blade itself enables me to use a much longer blade than in any former
propeller so that I obtain a more effective and greater amount of acting surface in
a longitudinal direction and I am enabled besides to dispense with any outer
supporting rim or band necessary in that construction.
The surface of my improved blade A which being a segment of a helix is formed
on straight lines that are perpendicular to and radiate from the axis of the carrying
hub or Cylinder B.
It is of equal thickness above the base or bottom line at and along this bottom
line it curves outwardly and downwardly on both faces to form a web or flange b
along its base from end to end.
This flange is then substantially at right angles to the surface of the blade and
gives the required strength and stiffness along the bottom of the blade where it
springs from the Cylinder.
The front edge of the blade is made somewhat thinner than the principal
portion or body to give it a fin like form especially at the lower edge and at the
point also where it is rounded off as seen in figures 1 and 2.
The base of the blade is placed diagonally across and projects from a fastening
Block D which I prefer to form solidly with the blade and in one piece.
The ends of this Block are made to take over and embrace the rim of the hub or
Cylinder and for that purpose it has dovetailed grooves C¹C in the ledges c¹ c¹,
one of which receives the front edge of the Cylinder rim while the other fits over
a projecting wedge shape portion B¹ provided on the rear edge or opposite end of
the cylinder rim.
When placed upon the rim B and pressed forward the tapering form of this
projection serves to lock it firmly in position.
Fastening bolts g g are then passed through the blocks and through the cylinder
rim beneath to secure the blades.
In applying or forming this fastening block D I employ two modes of joining it
and the blade together according as may desire to increase the speed of the pro-
peller or add to its power at the expense of its speed. One of these forms consists
in connecting the blocks and the bottom of flange of the blade together by means of
à contracted neck portion d which springs from the face of the block in a curve
and meets and joins the edge of the wheel or flange thereby giving a clearance or
space between the flanges and the face of the block.
This contracted neck portion is an important feature in my invention as it
carries the blade out into the water where it has more resisting power.
This construction is shewn in figures 1..2.. and 4.
But by leaving out this neck or clearance beneath the blade and bringing the
flange directly down to the block as seen in figures 6. and 7. I make the block
practically a widening and extension of the flange.
This construction brings the blade closer to the Cylinder and thereby contributes
to stiffness or reduces the spring of the blade.
If preferred the block may be secured to the Cylinder by a wedge shaped tongue
and a groove or mortice.
The mortice E is cut across the Cylinder and is widened at the bottom to give a
dovetailed form, and the convex surface of the Cylinder is finished off flat for
a seat F.
The underside of the block is provided with a tapering tongue or tenon E, to fit
the slot E¹ and this face of the block is made on a curve to fit the seat F.
Bolt holes are made through the block and into the Cylinder B. for fastening
Bolts S. This fastening securely holds the blades in place as shewn in figures 8. 9.
and 10.
I do not limit my invention to the exact details of either of the means shewn
for affixing the blades to the hub or cylinder B. as the blades may be secured in a

page_text: variety of ways or if preferred they may be made in one piece with the hub or
cylinder.
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In applying this propeller to a Vessel where the well-room will not permit a full
length of blade to be used at both ends of the propeller hub, I reduce the length
by removing a sufficient amount of blade from one or both ends but preferably at
the rear end of the blade as shewn in Figure 8.
These improvements enable me to increase the action of Screw Propellers and
also reduce the weight and bulk of metal that has been heretofore required at
the hub.
I claim as my invention
The propeller for Ships or Vessels consisting of the hollow cylindrical hub B.
having central bearing for the propelling shaft and the spiral blades A. having the
bottom web or flange b with contracting neck d and fastening block D. and
extending beyond the end of the Cylinder constructed and applied together
substantially as described.
'
2nd In a propeller for steam Ships or Vessels the combination with a hollow
cylindrical hub B. of spiral blades A.-the length of which is in excess of the
width that extend over and beyond the end of the Cylinder and are secured to the
cylinder by fastening block D substantially as described.
3rd The combination with the propeller blade A of the fastening block D having
dovetail grooves C. C which are adopted to take over the rim of the cylinder
substantially as described.
4th The combination with the propeller blade A of the fastening block d.having
dovetail-grooves C. C and joined to the blade by contracting neck d substantially
as described.
5th The combination with the fastening block D having dovetail grooves C. C
of the wedge shape projection on the inner rim of cylinder hub substantially as
described.
°
6th In a propeller for Ships or Vessels the combination consisting of cylindrical
hub B. and spiral blade A with contracted neck and bearing surface D with
tapering tongue and groove tenon E substantially as described.
7th The herein described propeller blade consisting of the spiral blade A having
the bottom flange and the fastening block joined thereto substantially as and for
the purpose set forth.