Improvements in Screw Propellers.
Year: 1898

page_text: Date of Application, 13th Apr., 1898-Accepted, 18th June, 1898
COMPLETE SPECIFICATION.
Improvements in Screw Propellers.
I, CHARLES EMIL OLSEN, Fisherman, of Bowery Beach, Cape Elizabeth, in the
County of Cumberland, and State of Maine, one of the United States of America, 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 :—
The object of this invention is to provide an improved propeller for vessels in which
the blades will have an independent movement with respect to the head that will
prevent the said blades "dragging" when the rotation of the propeller shaft has
ceased. This construction is especially desirable in ships or vessels that carry an
auxiliary engine and depend for their main driving power upon the sails, and by the
use of this propeller the blades will offer the least obstruction to the progress of the
vessel when the engine is stopped. This is accomplished by connecting the blades
to the hub in such manner that when the propeller is revolved or rotated it will
act in the usual manner to force the vessel forward, and when the propeller shaft
is stopped the said blades will automatically assume a position parallel with the
direction of the boat so as to cut the water and not drag.
Having the above objects in view, the invention consists in connecting the blades
of the propeller pivotally to the hub and provide stops for limiting the movement or
throw of said blades with respect to the hub.
The following specification will give a detailed description of the several parts
which constitute my invention, reference being had to the drawings and to letters or
numerals thereon which designate the different features of construction that form a
basis of the claim.
In the accompanying drawings, forming part of this specification,
Figure 1 is an elevation showing a propeller constructed in accordance with my
invention,
Figure 2 is a side view of the propeller with the near blade removed,
Figure 3 is a sectional view through the hub and propellers,
Figure 4 is a detail view of the hub with the blades removed, and
Figure 5 is a detail view of the means for connecting the blades to the pivot
pins.
1' designates the propeller shaft to the end of which is rigidly secured a head. 2
having sides which correspond in number with the number of blades it is desired to
use, the drawings showing a four bladed propeller. The sides of the head or hub 2
are each provided centrally with the projecting pin 4 forming a pivot or bearing for
the blade, and the said head is provided with a circular recess or socket 5 surrounding
the pin' to receive the corresponding end of the blade. The wall of this circular
recess or socket is cut away at one side, as shown, forming shoulders 6, for the
purpose hereinafter set forth.
7 designates the blades of the propeller which are of peculiar construction to
adapt them for the particular objects which I have in view. The inner end
of each propeller blade is rounded or shaped to conform to the configuration
of the socket in the 'hub and 'is provided centrally with an axial opening
to receive the pivot or bearing pins von said hub. -The blades are also

page_text: provided at their inner ends with projections or lugs 8 that pass into the recesses
or extensions of the sockets and contact with the shoulders formed thereby. These
lugs in connection with the recesses or extensions of the sockets limit the throw of
the blades in both directions, and are consequently positioned with respect to the hub
so that when said lugs or projections are in engagement with either one of the 5
shoulders 6 the blades will be deflected to properly act upon the water to push the
vessel forward. It may also be stated that as the blades are free to swing or rotate
upon the pivots the axis thereof does not pass through the centre of said blade but
the rear side is extended to present a greater amount of surface to be contacted by
the water and thereby acted upon to automatically throw the blades in proper
relative position or deflected with respect to the shaft. It will be noted that the
shoulders 6 are of a distance apart to permit the blade to swing or be thrown
at an angle on opposite sides of the longitudinal line with the shaft; this provides a
construction by which the propeller is operated to push the boat forward irrespective
of the direction of rotation of the propeller shaft, and the said blades will be free to
rotate or inove on their pivots and also automatically assume the position parallel
with the shaft to cut the water.
From the foregoing description it will be seen that the principal object of the
invention is to so connect the blades to the hub that when the shaft is stopped the
movement of the boat through the water will bring the blades to a position to cut
the water and not drag, and when the shaft is started the greater surface which
to one side of the axis of the blade will be acted upon to turn the blade in the
proper direction for action.
It is obvious that the blades can be held upon the pivot pins in any particular
manner which will allow a free rotation, but the construction herein shown and
described is the preferred form as it permits the blades to be readily removed for
repairs or for the purpose of renewing them. For this purpose the outer end of each
pivot pin is provided with an annular groove or recess 9 which is engaged by a
bearing carried by the blade and consisting of two parts 10 and 11. The blades are
provided with transverse openings which receive the sections 10 and 11 of the
bearing. It will also be understood that the bearing surfaces of the blades and hub
could be and preferably are provided with grooves to receive the ordinary anti-
friction ball bearings that would allow free movement of the blades and thereby
prevent them from offering any obstruction or impediment to the progress of the
boat. The inner ends of the blades are preferably seated within the hub, and a
tight joint provided at this point in order to exclude any foreign matter from finding
its way into the socket and thereby preventing the proper contact of the lugs on the
blades with the shoulders.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a propeller, the combination with a hub having pivot or bearing pins project-
ing therefrom, blades having axial openings by which said blades are placed in pivotal
engagement with the hub, and stops for said hubs adapted to limit the pivotal
movement of said blades.
2. In a propeller for the purpose set forth, the combination with a hub having
pivot or bearing pins projecting therefrom, blades having axial openings by which
said blades are placed in free pivotal engagement with the hub, stops formed on the
hub, and lugs projecting from the blades to engage said stops, substantially as shown
and for the purpose set forth.
3. In a propeller, the combination with a head having sockets in the sides thereof
and extensions on the socket forming shoulders, of blades seated within the sockets
and provided with lugs that engage the shoulders formed by the extensions of the

page_text: 4. In a propeller of the character described, the combination with the hub having
sockets therein and pivot pins projecting from the centre of the sockets, blades freely
pivoted upon the pins, means for holding the blades in engagement with the pins,
and stops for limiting the throw of the blades, substantially as shown and for the
purpose set forth.
5. In a propeller of the character described, the combination with a hub having
sockets and pivot or bearing pins projecting centrally therefrom, of the blades seated
within-the-sockets upon the pivot pins, said blades having a greater contact surface on
one side of the axis, means for connecting the blades to the pivot pins, lugs project-
ing from the inner ends of the blades and engaging shoulders or stops formed on the
hub, substantially as shown and for the purpose set forth.
6. In a propeller of the character described, the combination with the hub having
sockets with pivot or bearing pins projecting centrally therefrom, blades seated on
the bearing pins and having lugs or projections adapted to engage shoulders or stops
on the hub, anti-friction bearings between the parts, the blades having a greater
surface to one side of their axis and transverse openings communicating with the
pivot pins, removable bearings passed into said openings to engage the pivot pins, the
parts being constructed and organized substantially as shown and described.
Dated this 12th day of Anril 1898
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.