IMPROVE- MENTS IN OR RELATING TO FEATHERING APPARATUS FOR SCREW PROPELLERS
Year: 1885

page_text: I, ROBERT. THOMAS BELLS of 42 Windsor Street Birkenhead in the County of
Chester, Engineer do hereby declare the nature of my said invention for IMPROVE-
MENTS IN OR RELATING TO FEATHERING APPARATUS FOR SCREW PROPELLERS to be
as follows:
This invention has for its object a simpler form of feathering screw apparatus,
than that hitherto in use and one that will admit of the employment of three or
four blades without enlarging the boss, the maximum in other feathering screws of
my acquaintance being only two.
By this ability to use three or four blades I can apply the apparatus with
economy to boats with twin screws, to boats with shallow draught, and to men of
war or other vessels which require that there shall be a large surface of screw and
all of it deeply submerged so that no part shall appear near the surface of the
water, and be consequently exposed to cannon balls. I also by my arrangements
can make my blades and boss, of cast steel and yet have brass bearings, and also
if desirable use brass shanks to steel blades. I place my boss on a hollow shaft as
in other cases, and bring the shaft of the feathering apparatus through the hollow.
The first coupling of the main shaft inside the ship I make strong enough however
to be hollowed out sufficiently to enable me to fix on the feathering shaft a worm
wheel and worm, and I bring the shaft of said worm through the coupling so that
it can be worked preferably by beveled wheels gearing into a larger annular beveled
and spur wheel combined loose on or round the main shaft. The spur wheel gears
into a winch fixed to the side of the tunnel.
Instead of the spur wheel I may use a simple smooth brake wheel and apply a
brake strap round it fixed to the tunnel at one end. By applying the brake and
turning the engine slowly in either direction I can feather or unfeather the screw
to any desirable extent.
This worm apparatus turns the inner shaft and feathers the screw as hereafter
described. The other end of the inner shaft is screwed and carries a cross head or
spider with as many arms as there are blades of the screw propeller. Links or
connecting rods from these arms pass through orifices in the main boss and are
linked to arms or levers on the shanks of the blades. These shauks have two
collars, one on each end of the bearing, and the top one with very large surface.

page_text: These hold the shank firmly in place. They are preferably cast solid on the
blades, and lined in the bearing with brass. The bottom collar is loose and put on
with socket joint and screws from the inside passing through the collar into the
blades. These shanks are placed in adjustable brasses or bearings in the boss
through apertures which are afterwards filled by a cap and wedge hereafter
described, and are then linked up to the links by the aid of man holes in the outer
boss or covering. The actual boss to which the blades are attached or against
which they abut is preferably of cast steel, and square inside for four blades.
I place a lining between the blade end and this boss. The blade shank flanges and
packing rings are turned and the boss bored so as to fit, and thus give the blades
a bearing on the boss or its ring as well as on the bearings through the shanks.
When the shanks are in position the cap of the bearing is put on and the
remainder of the hole filled up with a wedge pushed in from inside and then held
against a square part of the inner boss by means of set screws or their equivalent.
A pointed cap or." bonnet" covering the feathering shaft end, the spider and hole
in the boss is now screwed on, and the apparatus is complete.
To feather the blades the worm is turned the required number of turns, and in
the required direction, this draws the spider or cross head in or out, which in turn
draws the shanks round by means of the links, an indicator shows the number of
revolutions turned, and a pair of pawls or other locking device is used to hold the
whole steady when adjusted; to reverse back to the original position the winch is
turned the reverse way.
These blades can also be feathered by the application of a short shaft through the
stern post, without going through the propellor shaft, the short shaft acting as a
box spanner fitted on the end of a short shaft inside the boss. On the end of this
shaft is a pinion working into a tooth wheel fitted on the end of the screw that
works the spider. The screw is turned, one end to fit into a hole bored a few
inches in the end of propeller shaft, the other end fitted into a frame for the
purpose inside the boss. To work this arrangement the engine is stopped on top
or bottom centres then the box spanner is pushed into the socket arrangement in
boss to receive it; the handle is turned the required way to feather.

page_text: Propellers.
I, ROBERT THOMAS BELLS of 42 Windsor Street, Birkenhead, in the County of
Chester, 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:-
-
This invention has for its object a simpler form of feathering screw apparatus
than that hitherto in use, and one that will admit of the employment of three or
four blades without enlarging the boss, the maximum in other feathering screws of
my acquaintance being only two.
By this ability to use three or four blades I can apply the apparatus with
economy to boats with twin screws, to boats with shallow draught, and to men of
war or other vessels, which require that there shall be a large surface of screw,
and all-of it deeply submerged so that no part shall appear near the surface of the
water, and be consequently exposed to cannon balls; I also by my arrangements
can make my blades and boss of cast steel, and yet have brass bearings, and also, if
desirable, use brass shanks to cast steel blades.
It is best described by aid of the accompanying drawings in which—.
Figures 1 and 2 are longitudinal sections, and
Figure 3 end elevation of apparatus with hood removed.
Figure 4 transverse view through first coupling showing mode of actuating.
In these M is the boss, this is placed on a hollow shaft A containing shaft Q of
the feathering apparatus; this is turned down at points to a little smaller diameter
to prevent friction in main shaft hole all along. The first coupling R, Figure 4, of
the main shaft A inside the ship, I make strong enough to be hollowed out
sufficiently to enable me to fix on the feathering shaft a worm wheel S and worm 8,
and I bring the shaft T of said worm through the coupling and attach to it a
winch handle t or if preferred gear it into an annular beveled wheel running loose
on the coupling and gear that to a winch in any convenient position. In practice
however I prefer to make the engine itself feather the screw, and this I accomplish
by a brake arrangement suggested to me by my Patent Agent, and for which I am
this day applying in conjunction with him for a complete patent.
The worm apparatus in either case turns the inner shaft and feathers the screw
hereafter described. The other end of the inner shaft is screwed and carries a
cross-head or spider B with as many arms as there are blades of the screw propeller.
Links or connecting rods C from these arms pass through orifices in the main
boss M and are linked to arms or levers E on the H, H shanks of the blades.
These shanks have two collars F¹ F, one on each end of the bearing, and the top
one with very large surface. These hold the shanks firmly in place. The top
collar is cast solid on the blades, and lined in the bearing with brass. The bottom
collar F is loose, and put on with socket joint G and screws g g from inside,
passing through the collar F2 into the blades H. These shanks are placed in
adjustable brasses or bearings i in the boss through apertures which are afterwards
filled by a cap I and wedge K hereafter described, and are then linked up to the
links C by the aid of man holes L in the outer boss or covering M.

page_text: The actual boss to which the blades are attached or against which they abut is
preferably of cast steel, and square inside, for four blades. I place a lining N
between the blade end and this boss. The blade shank flanges are turned and the
box bored so as to fit, and thus give the blades a bearing on the boss or its lining
as well as on the bearings through the shanks. When the shanks are in position
the cap of the bearing is put on, and the remainder of the hole filled up with a
wedge pushed in from inside, and then held against a square part of the inner boss
by means of set screws O or their equivalent. A pointed cap or "Bonnet" P
covering the feathering shaft end, the spider and hole in the boss, is now screwed
on, and the apparatus is complete. To feather the blades the worm is turned the
required number of turns, and in the required direction, this draws the spider or
cross-head in or out, which in turn draws the shanks round by means of the links,
and a pair of pawls or other locking device is used to hold the whole steady when
adjusted.
For the simple arrangement for turning the feathering shaft herein shown
I prefer for a locking device to simply tie the winch handle to the main shaft by
spun yarn. It is thus always in its place ready to be used and is safe to be there,
as there is no means of locking the feathering apparatus if it be taken off,
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I would say that
I make no claim here for the internal shaft with its spider and arms, nor yet
for the bonnet or the process of feathering a screw, but I declare that what
I claim is:-
1st. The combination with the internal shaft spider and arms, of an arm
projecting from the end of the shank of the blade, or from a collar firmly fixed
thereto.
2nd. The mechanism for holding the blades secure to the boss, substantially as
herein set forth and described.