Screw Propeller with Blades which can be Adjusted During Rotation.
Year: 1893

page_text: Date of Application, 23rd June, 1893-Accepted, 29th July, 1893
COMPLETE SPECIFICATION.
Screw Propeller with Blades which can be Adjusted During
Rotation.
I, FRITZ OTTE of 59 Lohmühlenstrasse, Altona, Germany, Engineer 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 a screw propeller the blades of which can be
adjusted or turned to the required pitch while propelling or rotating by mere
motion of the propeller shaft in the direction of its axis, and so that not only the
speed of the vessel can be regulated thereby but that its direction of motion can
be reversed without in any way altering the speed or direction of motion of the
engine while permitting easy handling of the vessel.
Figure 1 of the drawings is a plan view, Figure 2 transverse section through the
boss and shaft and Figures 3 and 4 longitudinal sections through the boss at right
angles to each other.
Each blade a of this propeller is at its root end provided with a round flange b
so inserted in the two parted hollow boss that the blade a can turn on its axis
vertically to the propeller shaft d. On each flange face near the circumference is
provided a lug e working each in a groove f formed on two opposite sides of a
block g fixed on the propeller shaft d and capable of sliding in the boss in the axial
direction of the shaft.
Assuming that the shaft is protruded axially to its furthest point to the right,
then the grooves will hold the lugs e in such a position that the pitch angle of
the blades is a maximum and for quickest forward motion of the vessel.
If the shaft during motion is pushed from the extreme right to the left the
grooves will carry the lugs e with them so that the blades are turned vertically to
the shaft and the angle of the propeller surface or the pitch is diminished and the
speed of the vessel diminished. In the medium position the blades stand so that
the angle of the blades is nothing and the vessel stands still. If the shaft is pushed
from the medium position further to the left the angle will become negative that
is the propeller blades will form left hand screw thread instead of right hand screw
thread and the vessel will go astern. The more the shaft is pushed to the left the
greater becomes the angle of the blades and the greater the pitch and hence also
the speed for going astern.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
1. A screw propeller with adjustable blades and with a boss mounted on the
shaft so that the latter can slide axially through it while the boss is prevented
from so sliding the shaft having fixed thereto a block with grooves and the blades
at the root or boss end being fitted each with a lug that works in one of the said
grooves, the construction and action being such that the blades are turned according
to the required pitch or for ahead or astern motion according as the shaft with its
grooved block is slided along axially substantially as set forth.
2. The construction of screw propeller with adjustable blades as described with
reference to the drawings.
Thaind th: 00-1 1
T
1000