IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF PROPELLER DLADES FOR THE PROPULSION OF VESSELS.
Year: 1873

page_text: LETTERS PATENT to John Collis Browne, of The Cedars, Hampton
Wick, in the County of Middlesex, Physician, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT OF PROPELLER
DLADES FOR THE PROPULSION OF VESSELS.
PROVISIONAL SPECIFICATION left by the said John Collis Browne at
the Office of the Commissioners of Patents, with his Petition, on the
23rd January 1873.
I, JOHN COLLIS BROWNE, of The Cedars, Hampton Wick, in the
County of Middlesex, Physician, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE CONSTRUCTION AND ARRANGEMENT
OF PROPELLER BLADES FOR THE PROPULSION OF VESSELS," to be as follows:-
This Invention relates to the construction and arrangement of pro-
peller blades upon a shaft, such blades being so shaped that a reverse
twist of the screw starts from the boss of each pair in order that the
water which is thrown backwards from the entering blade is received by
the back of its neighbouring blade, this being curved to receive it and
again act upon it for propelling the vessel. The body or neck of each
blade is in a central line with the axis of the shaft, and the blades are

page_text: carried fore and aft in pairs where they terminate in points or are
narrowed from about mid-distance to the tails or ends. Each blade is of
the same curvature, consequently their action is the same for the back-
ward motion as for the forward motion of the vessel.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Collis Browne in the Great Scal Patent
Office on the 23rd July 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
COLLIS BROWNE, of The Cedars, Hampton Wick, in the County of
Middlesex, Physician, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of January, in the year
of our Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Collis Browne, Her special licence
that I, the said John Collis Browne, my executors, administrators, and
assigns, or such others as I, the said John Collis Brownc, my exccutors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, excrcise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE CONSTRUCTION AND ARRANGEMENT OF PROPELLER BLADES POR THE PROPULSION
OF VESSELS," upon the condition (amongst others) that I, the said
John Collis Browne, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said In-
vention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said John Collis Browne, do hereby
declare the nature of my said Invention, and in what manner the same is
20
1
1

page_text: the following statement thereof, reference being had to the Drawings
hereunto annexed, that is to say :-
-
'This Invention relates to the construction and arrangement of pro-
peller blades upon a shaft, the blades being so shaped that a reverse
twist of the screw starts from the boss of each pair in order that the
water which is thrown backwards from the entering blade is received by
the back of its neighbouring blade, this being curved to receive it and
again act upon it for propelling the vessel. The body or neck of each
blade is in a central line or nearly so with the axis of the shaft, and the
blades are carried fore and aft in pairs where they terminate in points or
are narrowed from about mid-distance to the tails or ends. Each blade
is of the same curvature and dimensions, or nearly so, to ensure their
action being the same for the backward motion as for the forward motion
of the vessel.
My Invention will be more clearly understood by reference to the
accompanying Sheet of Drawings in which Figures 1 and 2 show side
and end views of two pairs of blades a, a', a³, a³, upon the one boss b,
and mounted upon a shaft c, to which the boss is keyed in the usual
manner. The blades of cach pair are exactly alike in their construction,
and are fitted or arranged so that a reverse twist of the screw starts
from the boss, that is in the opposite direction to each other, so that the
column or cable of water, which is acted upon and thrown back so to
speak from the inner face of the entering blade a, is received by the
outer face or back of the blade a', and is again acted upon by that blado
before it leaves the stern of the vessel in which the propeller is fitted.
The same action upon the water takes place by the blades a³, a³, con
sequently there is, when the screw is rotated, a double body column or
cable of water continuously drawn in by the two forward blades, and as
it is ejected from those blades, it is impinged upon by the backs of the
two after blades, and that action is utilized for propelling the vessel.
All the four blades of the two pairs are preferably of the same shape
and size, but they may be of different shapes and sizes and arranged in
any suitable manner so long as the two blades of cach pair are placed
back to back to enable a double action to take place upon the water, when
the rotation is reversed; the consequence is that a vessel can be drawn
astern with almost the same facility and speed as by the thrust forward.
Figures 3 and 4 represent a modification of the shape of the blades,
and instead of the four blades being upon the same boss as in the

page_text: previous case, cach pair is upon a boss of their own, so that when fitted
upon the shaft c the proper angle and distance of the two blades of each
pair can be set to obtain the best results as to speed from the vessel in
which the propellor may be arranged.
The two blades of each pair can be further modified by increasing the
breadth of cach, and they can be set farther apart and with a scoop-
shaped face for pocketing or biting the water to a greater extent.
Figure 5 shows two pairs of the modified shaped blades upon a shaft
in the stern of a vessel, but I do not limit myself to placing them in
that position, as they may be at the bows or at the sides, according to
the construction of the vessel in which the propeller has to be fitted.
The blades can also be arranged to feather upon their bosses, by which
a greater or a lesser hold or bito of the water can be had, according to
the load carried by the vessel, it being well known that a fixed number
of rotations of a screw must take place to effect the necessary progress
through the water with respect to fixed blades, and this without respect
to the actual load carried, whereas with feathering blades the "pitch'
can be increased or diminished to suit the load and the speed required.
"
And having now described the nature of my said Invention and in
what manner the same is to be performed, I declare that I claim,-
Firstly. Constructing and arranging propeller blades upon a shaft in
pairs, so that the water after leaving the face of one blade is acted upon
by the back of the neighbouring blade of the pair for propelling a vessel
as described and shown.
Secondly. I claim constructing and arranging the blades of screw
propellers, so that a reverse twist of the screw or thread starts from the
boss of cach pair to the ends, for the purpose described.
In witness whereof, I, the said John Collis Browne, have hereunto
set my hand and scal, this Twenty-second day of July, One
thousand eight hundred and seventy-three.