Improvements in Screw Propellers.
Year: 1890

page_text: Date of Application, 25th Mar., 1890-Accepted, 26th Apr., 1890
COME TE STECIFICATION.
[Communicated from abroad by JUAN ANGLÉS Y GIBERT, of Barcelona, in the
Kingdom of Spain.]
Improvements in Screw Propellers.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex do hereby declare 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 :-
This invention relates to screw-propellers and is illustrated in the accompanying
drawing in which
Figure 1 represents the propeller viewed endwise of the shaft upon which it is
fixed.
Figure 2 represents the same viewed at right angles with the axis of the shaft
from a point in the line of intersection between the planes of the two blades.
Figure 3 represents the same viewed from a position in the plane of one of the
blades diagonal to the axis of the shaft, riz.: from the direction of the arrow,
Figure 2.
Figure 4 represents the same viewed at right angles to the shaft and in a line at
right angles to the line of intersection between the planes of the two blades.
Figure 5 is a modification in which the two blades instead of being arranged
opposite to each other are arranged at different points lengthwise of the shaft.
a is a hub keyed fast to the shaft b; c and d are the blades. These blades are
preferably, each of the form represented in flat and edge view in Figure 3, each
consisting of a semi-elliptical disc. These discs are placed in planes which cross
each other at right angles and which are each inclined at an angle of about 45° to the axis
of the shaft. The result of this form and location is, that when the shaft is revolved
upon its axis, the space included within the sweep of the blade is substantially
cylindrical. This concentrates and equalizes the forces equidistant from the axis of
rotation, and for a minimum of radius of surface brings a maximum of space within
the sweep of the blades and therefore produces a maximum of water displacement
under their action.
With this new scrow as a type, modifications may be deduced in accordance with
substantially the same system. Thus, a screw with a single half disc formed and
arranged relatively to the shaft like either of the discs above described. revolves also
in a spherical volume. Again, half discs may be placed one alongside of another on a
single axis, each of which revolves in a spherical volume as shown in Figure 5.
A propeller as above described, four metres in diameter, includes within its sweep
33 cubic metres; whereas, the best form of propeller known to me heretofore,
6 metres in diameter, fell short of the volume, 33 cubic metres, and on account of its
greater diameter could not revolve with the same velocity as mine under the samo
propelling power.
I am aware that it has been proposed to construct propellers from flat blades formed
in half or lesser portion of a circle combined with each other at an angle of less than
45°; but in no case to my knowledge, has it ever been proposed to construct a
propeller which would include within the sweep of its blade, a cylinder the length of
which was substantially equivalent to its diameter, which is accomplished; as I believe,
for the first time by the present invention in arranging my two semi-elliptical blades
substantially at right angles with one another and so that the plane of each of them
forms an angle of 45° with the axis of rotation.
By this construction also the blades actually traverse one half of the space within
the cylinder of rotation.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by my
foreign correspondent I declare that what I claim is :-
A propeller consisting of two semi-elliptical flat blades combined at right angles
with one another and each at an angle of 45° with the shaft substantially as described,
whereby the peripheries of each blade describes a cylinder of substantially equal
length and diameter and the face of the blade acts substantially throughout one half
the space included within this cylinder, as set forth.
Dated this 25th day of March 1890.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.