IMPROVEMENTS IN THE CONSTRUCTION OF SCREW PROPELLERS WITH ADJUST- ABLE AND FEATHERING BLADES
Year: 1875

page_text: LETTERS PATENT to Frederick John Eyre, of Kingswear, near
Dartmouth, in the County of Devon, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF SCREW PROPELLERS WITH ADJUST-
ABLE AND FEATHERING BLADES.”
Scaled the 15th September 1875, and dated the 21st July 1875.
PROVISIONAL SPECIFICATION left by the said Frederick John Eyre
at the Office of the Commissioners of Patents, with his Petition,
on the 21st July 1875.
I, FREDERICK JOHN EYRE, of Kingswear, near Dartmouth, in the
County of Devon, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF SCREW PROPELLERS WITH ADJUST-
ABLE AND FEATHERING BLADES," to be as follows .—
This Invention has for its object improvements in the construction of
screw propellers with adjustable and feathering blades, and relates to an
improved construction of propeller applicable to vessels of any size,
and capable of being fitted to existing propeller shafts of the ordinary
construction.

page_text: arranged to be moved along over it as required for altering the positions
of the blades. The ring may be moved in various ways.
In one arrangement I have devised a strap, resembling the excontric
strap of a steam engine, and formed or provided with a couple of
projections or pins, encompasses the ring, the projections or pins of the
strap entering slots or notches in the prong of a forked arm which is
worked by means of a worm wheel fixed upon the axis of the forked
arm and actuated by a worm worked by hand or otherwise from the
deck or other convenient part of the vessel.
I provide an indicator for shewing the positions of the propeller
blades, said indicator being arranged with stops so that it cannot be
moved beyond the proper limits.
I arrange the mechanism so that during the changing of the position
of the blades for reversing the action of the propeller neither blade
shall at any time be capable of assuming a position in which both its
edges approach a common plane of 1otation. The arrangement is such,
morcover, as to preclude the blades being so moved as to cause injury to
the engine.
Propellers provided with my improved mechanism for altering the
positions of the blades may be constructed with blades of various forms,
but I propose to use a form of blade which when applied in conjunction
with my mechanism for altering the positions of the blades may be
caused to present similar operating faces to the water whether the vessel
be going ahead or astern.
The shifting ring may be protected from fouling by means of a
suitable casing.
By the use of propellers according to my Invention engines of
simplified construction, and consequently cheaper to construct than
ordinary reversing engines, may be employed.
30 SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick John Eyre in the Great Seal Patent
Office on the 21st January 1876.

page_text: Devon, but now of No. 7, Belsize Park, N.W., in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
year of
Letters Patent, bearing date the Twenty-first day of July, in the
our Lord One thousand eight hundred and seventy-five, in the thirty-
ninth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Frederick John Eyre, Her special
License that I, the said Frederick John Eyre, my executors, admini-
strators, and assigns, or such others as I, the said Frederick John
Eyre, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after 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 Inven-
tion for "IMPROVEMENTS IN THE CONSTRUCTION OF SCREW PROPELLERS WITH
ADJUSTABLE AND FEATHERING BLADES," upon the condition (amongst others)
that I, the said Frederick John Eyre, my exccutors or administrators,
by an instrument in writing under my, or their, or one of their hands
and scals, 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 Frederick John Eyre, 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 thercof, and the Sheet of Drawings
therein referred to, that is to say :-
This Invention has for its object improvements in the construction
of screw propellers with adjustable and feathering blades, and relates
to an improved construction of propeller applicable to vessels of any
size, and capable of being fitted to existing propeller shafts of the
ordinary construction.
In my improved propeller the boss is of ordinary size. The positions
of the blades can be altered whilst the propeller is in motion, and the
blades having been moved into any position will be by the moving
mechanism automatically locked in that position, and will so remain

page_text: In one arrangement I have devised a strap, resembling the eccentric
strap of a steam engine, and formed or provided with a couple of
projections or pins, encompasses the ring, the projections or pins of the
strap entering slots or notches in the prongs of a forked arm, which is
worked by means of a worm wheel fixed upon the axis of the forked 5
arm, and actuated by a worm worked by hand or otherwise from the
deck or other convenient part of the vessel.

page_text: Fig. 4; and Fig. 6 is a view showing the hollow boss and the root of the
blade in section, and the reversing apparatus in plan.
a, a, are the blades, each of which has formed at its root a number of
worm wheel teeth 6 (Figs 5 and 6). These teeth are formed only upon
a portion of the circumference of the root, so that the blade can never
be turned into a position in which both its edges shall approach a
common plane of rotation. Each blado is formed also with a circular
flange c working in a corresponding recess in the hollow boss d, cach
blade being kept in its place by a ring formed in two parts e, e¹, these
two parts being bolted in position, as shown in Figs 1 and 3
In lieu of the arrangement shewn the root of the blade may be made
in a separate piece from the blade itsolf, and formed with a projecting
part, to which the blade may be attached by bolts or by a cotter in the
ordinary way of making such like attachments, so that spare blades may
be carried, and a perfect blade substituted for a damaged one when
requisite This is specially applicable to large vessols. In goar with
the teeth on each blade is a worm, one of which is shewn at in Fig 6.
By rotating these worms the blades are turned. Each worm ƒ has
formed with or attached to it a concentric toothed wheel g arranged in
gear with another toothed wheel / (or it may be a sector) on the same
axis as a pinion 2. Each of the pinions 2 is actuated by a rack k
arranged to move in a direction parallel with the propeller shaft.
The two racks, one of which is clearly shewn in Fig. 5, are connected
to a common ring surrounding a projecting portion d' of the propeller
boss The ring is free to move to and fro over the projection d² in the
direction of the length of the propeller shaft. The ring is grooved and
in its groove carries a strap r (Fig 1) resembling the eccentric strap of
a steam engine This strap has a couple of projections or pins & which
enter slots in a couple of prongs n forming the fork arm of a bell-crank
lever, having its fulcrum at o, the other arm n¹ having jointed to it (so
as to leave a little play in the joint) a guided rod P, whose upper
end is
wormed and fits into a correspondingly wormed hand wheel q. by turning
which, in one direction or the other, the rod p will be raised or lowered
so as to draw the ring ɩ and the racks towards or from the vessel, and so
through the pinions, wheels and g, and worms f to turn the blades
for feathering the blades or reversing the action of the propeller.

page_text: The positions of the blades may be indicated by arranging the boss of
the hand wheel with teeth working into a sector carrying a pointer,
but other arrangements may obviously be adopted
The acting face a¹ of cach blade is flat, and the opposite face or
back a³ is curved for strengthening the blade in the ordinary way.
The arrangement shown in Figs 4, 5, and 6 may be modified by
forming teeth all round the root of the blade, and providing cach bláde
with two worms f, one at each side of its root, the additional worms
being driven by the wheels h.
Where it is not requisite that the blades should be capable of reversal
(feathering only being required) the pinions i may obviously be made.
somewhat larger in proportion to the wheels h, the amount of traverse
in such a case being less.
In large propellers additional locking apparatus of various constructions
may be applied so as to relieve the worms and teeth at the roots of the
blades from some of the strain Thus, for example, for feathering only
and where an uniform pitch only is required the additional locking
apparatus may consist of a trailing pawl carried by the circular flange c
of each blade, and arranged to drop into a corresponding recess in tho
boss d.
Where the pitch is to be variable the periphery of the flange c of cach
blade may be formed with a scries of notches or recesses to receive a
corresponding bolt or catch. The catch for holding each flange may be
fitted in a suitable hole in the rear end of the boss, and the bolts or
catches of the two blade flanges may be connected together by a cross
bar, which cross bar may be operated so as to move the bolts towards or
from the flanges by any convenient mechanical arrangement worked
from the deck of the vessel, as will be readily understood.
Having described the nature of my said Invention, and the mode
of carrying the same into practical effect, I desire to have it undor-
stood that I do not claim generally as of my Invention the constructing
screw propellers in which the blades are combined with apparatus
whereby the blades may be moved through any of or through all the
degrees of a circle, so that the pitch of the blades may be varied or the
direction of the propeller's action reversed whilst the propeller is m
motion without stopping or reversing the engines, I am aware it

page_text: has been proposed to do this in various ways; nor do I claim generally
the constructing the roots or axes of propeller blades with worm wheels
or teeth and actuating them by worms, screws, or racks; nor do I intend
to claim any of the mechanical parts of the apparatus herein-before
shewn and described when taken separately and apart from the com-
bination or application thereof, in manner and for the purposes herein
described; but what I consider to be novel and original and therefore
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, the combination of parts constituting the improved
screw propeller, constructed, arranged, and operating substantially as
herein described with reference to the accompanying Sheet of Drawings.
In witness whereof, I, the said Frederick John Eyrc, have hereunto
set my hand and scal, this Twentieth day of January, in the year
of our Lord One thousand eight hundred and seventy-six.