Improvements in Screw-propellers, and Apparatus connected therewith.
Year: 1897

page_text: Date of Application, 9th Aug., 1897
Complete Specification Left, 28th Apr., 1898-Accepted, 9th Aug., 1898
PROVISIONAL SPECIFICATION.
Improvements in Screw-propellers, and Apparatus connected
therewith.
I, SIDNEY HERBERT HOLLANDS, of "May Bank," Lansdowne Circus, Leaming-
ton, Co. Warwickshire, Mechanical Engineer, do hereby declare the nature of this
invention to be as follows:-
My invention relates to screw-propellers having blades capable of almost instant
reversal while in motion, as also when not running, by converting the propeller
from a left to a right-hand screw, or vice versa, specially applicable to non-reversible
engines or motors, which may thus always rotate in one direction, and dispense
with reversing appliances, besides gaining other advantages, including a means
of varying the pitch of the propeller, as may be found most advantageous to its
particular vessel.
I effect this by making each separate screw-blade rotate on its major axis
through part of a circle, by directly-applied hydraulic, or other fluid pressure.
The shank of each blade within the central boss, having a coarsely-pitched
screw-thread or multiple threads, or a twist formed on it, and fitting into a suitable
traversing nut, which is restrained from rotating while being forced backwards
or forwards on the said screwed or twisted blade-shank. The direct thrust of a
hydraulic ram or plunger, or other fluid pressure plunger or piston within the
propeller boss, is applied to each of these traversing nuts, and so arranged in
couples that they are virtually double-acting. The controlling or regulating
appliance, (which may be in multiple, and workable independently,) may be
placed in any desired position (or positions) in the vessel.
This appliance will consist of a pressure vessel, preferably a relatively small
cylinder fitted with a double-acting piston and end-covers, through one or both of
which a piston-rod passes, and which rod can be reciprocated either by hand-gear,
(preferably a hand-wheel and screw) or by power taken from any suitable
part of the main engine or shafting, or by both means.
A small pressure pipe will be led from each end of this cylinder, through the
hollow main shaft to the working cylinders within the hollow boss of the propeller;
being conducted into the hollow of the shaft, preferably by means of a stationary
two-way watertight annulus encircling the shaft, and having the pressure-pipes
connected to it. The hollow of shaft may be divided longitudinally,-instead of
having separate pipes passing. through it-thus forming two passages.
Dated this 9th day of August 1897.

page_text: Improvements in Screw-propellers, and Apparatus connected
therewith.
I, SIDNEY HERBERT HOLLANDS, of "May Bank," Lansdowne Circus, Leaming-
ton, in the County of Warwick, 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:-
My invention relates to improvements in the means of operating the blades of
reversible screw-propellers; .e., propellers the blades of which are capable of
being reversed, converting the screw from a right to a left-handed one, or vice versa
while the propeller is rotating. In addition to the reversal of the blades, they may
be adjusted to any desired intermediate position, thus making the pitch finer than
that due to the maximum position for either going ahead or astern.
The invention relates to imechanism for effecting this, and which may be either
operated by handgear, or by power taken from any suitable part of the main
engine or shafting, or by both means.
Such gear can be placed in any convenient position or positions in the ship or
other vessel. This may be termed the mechanism for transmitting and controlling
the power to operate the screw-blades.
66
The receiving mechanism to which the power is transmitted is placed within the
propeller boss, and acts directly on the movable blades, partly rotating them on
their major axes.
This latter or receiving" mechanism, is hydraulically worked, either water,
oil, or other fluid pressure being used, but preferably oil, and operates the blades
by the fluid pressure transmitted from the former, or transmitting" mechanism
through small pressure-pipes led aft through the hollow shaft of the propeller.
The "receiving" or blade-turning mechanism, or motor, consists of the follow-
ing parts:-
-
<
Within the central main boss, the shank of each movable blade has one or more
coarsely-pitched screw-threads, or an equivalent twist formed on it, and fitting a
suitable traversing nut, which is restrained from rotating while being forced
backwards or forwards in the direction of its axis along the screwed or twisted
blade-shank, which latter is preferably fitted with suitable anti-friction bearings
for its journals.
The direct thrust of a hydraulic, or other fluid-pressure ram, piston, or plunger is
applied to each of these traversing nuts, and so arranged in couples that they
are virtually double-acting.
The ram-cylinders have led and connected to them the pressure-pipes before
mentioned, coming from the " transmitting" and controlling mechanism.
This latter consists of a pressure vessel, preferably a relatively small cylinder
fitted with a double-acting piston and covers, through one or both of which covers
a piston-rod passes, and which rod can be reciprocated either by hand-gear,-
preferably a hand-wheel forming a nut, on a traversing screwed extension of the
piston-rod, (the wheel not shifting laterally,) or by power taken from any suitable
part of the main engine or shafting, preferably by the means hereinafter
described,-
,-or by both means.
A small pressure-pipe in communication with the space between the piston and
the end or cover of this "transmitting" and controlling cylinder, is connected
to and led from each end of it, through the hollow of the main shaft to the "receiv-
ing" mechanism or motor within the propeller boss.
A bye-pass is fitted to the transmitting cylinder, and may consist simply of a
pipe connecting the two pressure spaces, and fitted with an intermediate stop-cock,

page_text: preferably combined with a filling nozzle or orifice, so that in the event of small
leakage past the piston, the bye-pass when opened and closed at suitable times, will
virtually give the effect of unlimited stroke or traverse.
The fluid pressure is conducted to the pressure pipes within the hollow of the
main shaft preferably by means of a stationary two-way fluid-tight ring or annulus,
-(which may be made in halves)-embracing the main shaft, and having the two
outside pressure-pipes connected to it. The two inside pressure-pipes terminate in
Alush holes at the surface or periphery of the main shaft, which holes or openings
come respectively within the two parallel annular grooves or pressure spaces
within the stationary ring-and thus a continuation of the connecting system
is effected, from the stationary to the rotating portion, and so to the motor within
the propeller itself. In place of having separate pressure-pipes led through it, the
hollow shaft may be divided longitudinally thus forming two passages.
Referring to the accompanying drawings forming part of this specification,-
Figs. 1 and 2 are: (1) a transverse or athwartship section, and (2) a longitudinal
view of a half of the boss of the propeller, (the front half being removed.)-with
portion of the hollow shaft, and the rear cone or cap in section-and with blades
and gear removed. These two views show the preferred construction of reversible-
bladed propeller.
Fig. 3 is a section of the pressure-transmitting and controlling cylinder.
Figs. 3 & 4 also show a means of taking power from the main shaft to operate the
pressure-transmitting and controlling mechanism. Fig. 5 is a section of the
stationary two-way pressure ring or annulus.
This is fitted with U-section leather packing rings which maintain a fluid-tight
joint around the main shaft as it rotates within them.
The metal annulus, and the leather rings may both be put on in halves where
necessary, the latter being cut after being moulded to the right form and
diameter, then placed together around the shaft, and the cut surfaces neatly and
strongly re-joined with flexible leather cement, which makes an excellent joint, and
equal in strength to the leather.
Referring to Fig. 1,-A A are the screwed or twisted blade-shanks; B B are
the radially traversing nuts embracing them, and CC are the double-ended rams
actuating them, and sliding tangentially in the cylinders D, to which the pres-
sure is conducted through the cross-connected pressure pipes E.
F&F are the bearings of the blade-shanks, which are preferably of a suitable
anti-friction type.
GG are the halves of the hollow main boss; c is one of the ram-packing cup-
leathers in section; 6 are the bosses of the traversing-nut-arms, with their
cotters 6. In Fig. 2, D D are two of the four pressure-ram-cylinders, showing
pipe-connections E; F & F are the half-bearings of the blade-shanks, and g are
holes for bolts, clamping the halves of main boss or shell together.
The only portions in this view really in section, are the rear cone or cap H,
and the main shaft I. In Fig. 3, J J are the pressure-spaces on each side of the
piston K, which is packed with cup-leathers K. ¹ is the piston-rod with its
screwed extension and nut-hand-wheel L, to which is fastened the 2-tread pulley P;
and 0 is a 3-way bye-pass cock opening communication between the opposite sides
of the piston, and with the central nozzle ol for refilling when necessary.
In Figs. 3 & 4, R & R are two driving belts, one of which is open, and the
other crossed for reverse motion, both embracing the main shaft, (or a suitable
pulley on it,) and the pulley P attached to the hand-wheel L, the boss of which
forms a nut for the screwed extension of the piston-rod k¹, and which pulley
and wheel in rotating do not shift laterally. The belts are made so that normally
they hang slack and clear of the shaft, and so do not then transmit power from it,
but are provided with "jockey," or tightening rollers S, & S¹, which can be pressed
against either belt as required by means of a hand-lever, and thus taking up the
slack in the belt, cause it to grip the rotating main shaft and transmit power in
the required direction.

page_text: In Fig. 5, T is the metal annulus, or stationary pressure-ring, and tt are the
leather-section packing-rings, making a fluid-tight joint around the shaft;
ee are the radial holes in main shaft, in communication with their respective pres-
sure-ring spaces, and leading to the pressure-pipes E within the shaft.
Having now particularly described the nature of the said invention, and in what
manner it is to be effected, I declare that what I claim is :-
1. The combination in a screw-propeller with movable reversible blades, of a
fluid pressure motor within the boss to actuate the blades for the purposes of
reversal, or for change of pitch.
2. The use in combination with screw-propellers having movable reversible
blades, and a fluid-pressure motor within the boss for actuating the blades,-of
fluid-pressure transmitting and controlling apparatus, and its connections to the
propeller and shafting.
3. The improvements in screw propellers and apparatus in connection therewith
substantially as herein described, and illustrated in the accompanying drawings.
SIDNEY. H. HOLLANDS.