Improvements in the Feathering and Adjusting the Pitch of Screw Propellers, also the Method of Fixing Blades of Propellers to the Boss.
Year: 1893

page_text: Date of Application, 24th May, 1893-Accepted, 24th June, 1893
COMPLETE SPECIFICATION.
Improvements in the Feathering and Adjusting the Pitch of Screw
Propellers, also the Method of Fixing Blades of Propellers to
the Boss.
I, HUGH MCINTYRE, of 6 Oswald Street, Glasgow, North Britain, Marine
Surveyor, 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 :-
My invention relates to improvements in the feathering and adjusting the pitch
of screw propellers for the propulsion of steam ships; also in the fixing of blades
to the boss of propellers.
The feathering or adjusting screw propeller consists of a boss or centre and two,
three, or four blades. The boss is in two parts lengthwise, and the blades are each
in one piece having a worm wheel or part of a worm wheel either cast or keyed on
the inner end. These blades are so fitted in the boss that when both parts of the
boss are together the blades are held without further fastenings. A worm is also
inserted in the boss with a square or key end projecting through the boss to enable
the blades to be feathered from the outside. The worm may be placed either fore
and aft or across the boss and made to be wrought either through the fore stern
post above the shaft or from the deck through the shell either before or abaft the
propeller. When blades are to be fixed at a given pitch no worm wheel or worm
is fitted and a flat side is made on the inside flange with a corresponding flat in the
recess of the boss, or the flange or collar may be of any other shape, oblong or
square, as may be found best for fixing the blades in position.
In order that my invention may be properly understood and readily carried into
effect I have hereunto appended two explanatory sheets of drawings in the several
figures of which corresponding parts are marked with the same letters of
reference.
Figure 1 is a part elevation and part section showing my improvements.
Figure 2 is a plan of Figure 1.
Figure 3 is an end view partly in section.
Figure 4 is an end elevation.
Figure 5 is a plan of Figure 4-showing the blades in position for feathering.
Figure 6 is sectional end view showing the method of fixing the blades to the
boss when the blades are fixed at a given pitch.
A is the boss or centre of the propeller; B are the blades which are each in one
piece;
and C is the propeller shaft. The boss is in two parts lengthwise, and these
parts are held together by means of the nut. D on the end of the propeller shaft.
The end of the blades B which fit into the boss A are provided with flanges E, and
these flanges rest in grooves or recesses I in the boss, so that when the two parts
are put together, the blades A are held in their place without further fastenings.
A worm is also inserted into the boss A with a square end f projecting beyond
the boss, or in a recess through the boss, and this worm engages with a worm, disc,
or wheel G provided on one of the flanges of the blade. When the blades are to
be feathered the key at end of the rod H is screwed in to ƒ by means of the
handle m which operates the rack and pinion k k¹. When h has been screwed
into the rod is turned by means of the ratchet L and so operates the worms and
thus feathers or alters the pitch of the blades.
Although not shown in the drawings it is understood that there is a separate
worm for each blade.
When blades are fixed at a given pitch no worm wheel or worm is fitted, and a
flat side P is made on the inside flange with a corresponding flat Q in the recess of
the boss as seen more particularly in Figure 6.

page_text: 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. Feathering or adjusting the pitch of screw propellers in the manner substan-
tially as described and illustrated on the accompanying sheets of drawings.
2. The method of fixing the blades to the boss, substantially as described and
illustrated on the accompanying sheets of drawings.
Dated this 22nd day of May 1893.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.