IMPROVEMENTS IN SCREW PROPELLORS
Year: 1859

page_text: LETTERS PATENT to Hermann Hirsch, of Berlin, in the Kingdom of
Prussia, for the Invention of "IMPROVEMENTS IN SCREW PROPELLORS."
Sealed the 30th December 1859, and dated the 2nd July 1859.
PROVISIONAL SPECIFICATION left by the said Hermann Hirsch at the
Office of the Commissioners of Patents, with his Petition, on the
2nd July 1859.
I, HERMANN HIRSCH, of Berlin, in the Kingdom of Prussia, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SCREW
PROPELLORS," to be as follows:-
The special peculiarity of this Invention consists in the co-operation of the
centrifugal force obtained by its peculiar construction, which is as follows:-
Take a plain surface in the form of a true oval, in the proportion of about
three to two; in this describe a circle, the edges of which touch the outer edges.
of the oval in the width thereof only; in the centre of this circle is a small
circular hole, and two diameters intersecting each other at right angles are
drawn, one line extending the entire length of the oval, the other the entire
width of the same; a third line is drawn across the centre of the circle at an
angle of 45° from the other lines to the extreme edges of the oval; if the plain
surface be bent so as to bring the two halves of the line of 45° together, two
hollow cones will be formed, which will assume the form (when looking in front of
the Figure 8, their bases deviating but slightly from circles, the points of the
two cones being affixed to the driving shaft, side by side, as before mentioned; it
will appear evident that the cones will strike and enter the water alternately,"
thereby having the desired effect of propelling the vessel forward. This

page_text: principle admits of many modifications, such as making the cones of and from
an oval, circular, elliptical, or square form; the principle of this Invention being
the making of screw propellors of hollow cones.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Hermann Hirsch in the Great Seal Patent Office on the
2nd January 1860.
.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HERMANN
HIRSCH, of Berlin, in the Kingdom of Prussia, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of July, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Hermann Hirsch, Her special licence that I,
the said Hermann Hirsch. my executors, administrators, and assigns,
or such others as I, the said Hermann Hirsch, my executors, adminis-
trators, 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, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVEMENTS IN SCREW PROPELLORS," upon the
condition (amongst others) that I, the said Hermann Hirsch, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, 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 Hermann Hirsch, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed. to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
The special peculiarity of this Invention consists in the co-operation of the
centrifugal force obtained by its peculiar construction, which is as follows:-
Take a plain surface in the form of a true oval, in the proportion of about
three to two; in this describe a circle, the edges of which touch the outer edges
of the oval in the width thereof only; in the centre of this circle is a small

page_text: circular hole, and two diameters intersecting each other at right angles are
drawn, one line extending the entire length of the oval, the other the entire
width of the same, a third line is drawn across the centre of the circle at an
angle of 45° from the other lines to the extreme edges of the oval; if the
plain surface be bent so as to bring the two halves of the line of 45° together,
two hollow cones will be formed which will assume the form (when looking in
front) of the figure 8, their bases deviating but slightly from circles, the points
of the two cones being affixed to the driving shaft, side by side, as before
mentioned; it will appear evident that the cones will strike and enter the
water alternately, thereby having the desired effect of propelling the vessel
forward.
This principle admits of many modifications, such as making the cones of and
from an oval, circular, elliptical, or square form, the principle of this Invention
being the making of screw propellors of hollow cones.
In order to explain my said Invention as completely as possible, I now proceed
to describe the best means I am acquainted with for carrying the same into
practical effect, reference being had to the accompanying Sheet of illustrativo
Drawings, and to the numeral figures and letters of reference marked thereon
سام
circular hole, and two diameters intersecting each other at right angles are
drawn, one line extending the entire length of the oval, the other the entire
width of the same, a third line is drawn across the centre of the circle at an
angle of 45° from the other lines to the extreme edges of the oval; if the
plain surface be bent so as to bring the two halves of the line of 45° together,
two hollow cones will be formed which will assume the form (when looking in
front) of the figure 8, their bases deviating but slightly from circles, the points
of the two cones being affixed to the driving shaft, side by side, as before
mentioned; it will appear evident that the cones will strike and enter the
water alternately, thereby having the desired effect of propelling the vessel
forward.
This principle admits of many modifications, such as making the cones of and
from an oval, circular, elliptical, or square form, the principle of this Invention
being the making of screw propellors of hollow cones.
In order to explain my said Invention as completely as possible, I now proceed
to describe the best means I am acquainted with for carrying the same into
practical effect, reference being had to the accompanying Sheet of illustrativo
Drawings, and to the numeral figures and letters of reference marked thereon
respectively, as follows.
DESCRIPTION OF THE DRAWINGS.
I will first describe more particularly one modification which I find
useful.
Figure I. of the annexed Drawing represents a perfect oval or ellipse, of
which a, b, and d, e, are the major and minor axes respectively, and f, g, a
diameter inclined to these axes when the ellipse is folded on the line f, g, and
bent across the fold in such a manner that the points f and g are brought into
coincidence; each half of the ellipse so folded and bent forms a hollow cone,
as represented in front elevation in Figure II., and in side elevation in
Figure III., in both which Figures the dotted lines complete the outline that
would be visible if the whole ellipse were so bent and folded; but if before so
bending and folding the ellipse a portion of it be removed, leaving two sym-
metrical portions g, d, m, h, and f, e, l, k, and these portions be bent and
folded into the same positions as they would assume if the whole ellipse were
used, a propellor is formed consisting of two blades, which are portions of
hollow cones joining each other along n, o, the axis of the propellor, as repre-
sented by the solid lines in front elevation, Figure II., and in the side
elevation, Figure III.
As in practice it is necessary to have a proper boss for receiving the driving

page_text: shaft of a propellor, I either form it by adding material of a cylindrical or conoidal
form round the axis of a propellor formed as above described, thereby covering
the central portions of the blades, as indicated in Figures II. and III., or I
affix the blades formed as above described to a suitable boss, as represented in
front elevation in Figure IV., and in side elevation in Figure V., removing
each blade from the axis sufficiently far to admit the boss between them, but
retaining their respective inclinations to the axis in such a manner, that, were
the cones of which the blades form portions supposed to be completed, they
would, instead of touching each other in a line coincident with the axis of the
propellor respectively, touch opposite sides of a cylinder or conoid 2, J; 1', 8,
having for its axis the axis of the propellor.
Having now fully described the nature and object of my said Invention
of "Improvements in Screw Propellors," together with the best means I
am acquainted with for carrying the same into practical effect, I would
remark, in conclusion, that I do not confine myself to any particular pro-
portions of the axes of the ellipse, nor to any particular inclination of the
folding diameter, nor to any particular form or proportion of the symmetrical
portions forming the blades; but I claim as my Invention intended to be
secured to me by the herein in part recited Letters Patent, the mode of
forming a propellor by the folding and bending of two symmetrical portions of
a plane figure, so that these portions become respectively parts of two hollow
cones, which if they were supposed to be completed would touch each other
along a line coincident with the axis of the propellor, or respectively touch on
opposite sides a cylinder or conoid, having for its axis the axis of the propellor.
In witness whereof, I, the said Hermann Hirsch, have hereunto set my
hand and seal, this Twenty-ninth day of December, in the year of
our Lord One thousand eight hundred and fifty-nine.
HERMANN HIRSCH. (L.S.)
Witness,
ALEX. PRINCE, Jun.,
Patent Office,
4, Trafalgar Square, Charing Cross.