Improvements in Screw Propellers.
Year: 1893

page_text: Date of Application, 16th Nov., 1893
Complete Specification Left, 19th Jan., 1894-Accepted, 24th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Screw Propellers.
I JAMES STEPHENS of Stonehouse in the County of Gloucester Engineer do
hereby declare the nature of this invention to be as follows:-
This invention of improvements in that class of screw propellers for the
propulsion of ships or boats known as feathering or reversing propellers, (in
which each blade of the propeller is caused to rotate in the boss on its own axis.
through a certain angle by suitable mechanism), has for its object the production of
a stronger propeller and one more reliable in its action than those hitherto produced,
and is an improvement on the invention for which Letters Patent No. 20194.
A.D. 1892 has been granted me.
In carrying out this invention I construct a boss which I attach to a propeller
shaft in any well known manner. I bore holes in this boss transversely to its axis
of revolution for the reception of the shanks of the propeller blades and each hole
is so far removed from the other as to admit of the shanks of the propeller blades
passing entirely through or nearly through the boss and having the support of the
boss, on each side of the mechanism by which they are reversed, as described in
my former Specification refered to above.
1 bore the holes in the boss refered to above for the reception of the propeller
blades, on opposite sides of the axis of revolution, (they need not be in such a
position as to cause the blades to revolve in different planes of revolution, as
described in my former Specification refered to above), and so far from each
other as to allow of sufficient metal between them for strength, and for recesses
for the reception of hydraulic leathers for preventing the entrance of water to the
interior of the propeller boss, and also so as to allow of the racks for reversing the
angle of the blades (refered to hereafter) passing between the shanks of the propeller
blades, or of the reversing rod (referred to hereafter) passing between thein if other
modes of reversal are adopted.
Each propeller blade is secured in its hole so as just to revolve freely on its axis..
A convenient mode of causing the blades to revolve on their axes through the
nescessary angle is as follows. On the shanks of each of the blades, within the boss,
and about centrally as regards their length I cut segments of a spur wheel, and
fit in a recess passing along the axis of revolution of the boss, spur racks which.
gear into the spur segments on the shanks of the propeller blades.
In order to cause the propeller blades to assume a different or reverse angle to,
the axial line of the propeller, it is nescessary to give these racks a motion in the
direction of the axis, and this I do by coupling them to a rod or shaft, called the
reversing rod, which passes along the centre of the propeller shaft which is bored
to receive it. By giving a forward or backward motion to this rod by any.
convenient mechanism within the ship or boat, a reversal of the angle of the blades
of the propeller will be effected.
The reversal of the angle of the propeller blades, (as an alternative plan), may,
be accomplished by means of links attached at one end to the reversing rod and at
the other to levers on the shanks of the propeller blades; or by a suitably.
shaped cam attached to the reversing rod operating levers on the shanks of the
propeller blades.
Dated this 15th dow of November 1802

page_text: 1 JAMES STEPHENS of Stonehouse in the County of Gloucester 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 of improvements in that class of screw propellers for the
propulsion of ships or boats known as feathering or reversing propellers, (in
which each blade of the propeller is caused to rotate in the boss on its own axis
through a certain angle by suitable mechanism,) has for its object the production of
a stronger propeller and one more reliable in its action than those hitherto produced,
and is an improvement on the invention for which Letters Patent No. 20194
A.D. 1892 has been granted me.
In carrying out this invention I construct a boss which I attach to a propeller
shaft in any well known manner. 1 bore holes in this boss transversely to its axis
of revolution for the reception of the shanks of the propeller blades, and each hole
. is so far removed from the other as to admit of the sharks of the propeller blades
passing entirely through or nearly through the boss and having the support of the
boss on each side of the mechanism by which they are reversed, as described in
my former Specification refered to above.
I bore the holes in the boss refered to above for the reception of the shanks of
the propeller blades, on opposite sides of the axis of revolution, (they need not be
in such a position as to cause the blades to revolve in different planes of revolution
as was specified and described in my former Specification refered to above,) and so
far from each other as to allow of sufficient metal between them for strength, and
for recesses for the reception of hydraulic leathers or other suitable packing for.
preventing the entrance of water to the interior of the propeller boss, and also so
as to allow of the racks for reversing the angle of the blades (refered to hereafter)
passing between the shanks of the propeller blades, or of the reversing rod (refered
to hereafter) passing between them if other modes of reversal are adopted.
Each propeller blade is secured in its hole so as just to revolve freely on its axis.
A convenient mode of causing the blades to revolve on their axes through the
nescessary angle is as follows. On the shanks of each of the blades, within the boss,
and about centrally as regards their length, I cut segments of a spur wheel, and I
fit in a recess passing along the axis of revolution of the boss, spur racks which
gear into the spur segments on the shanks of the propeller blades.
In order to cause the propeller blades to assume a different or reverse angle to
the axial line of the propeller, it is nescessary to give these racks a motion in the
direction of the axis, and this I do by coupling them to a rod or shaft called the
reversing rod, which passes along the centre of the propeller shaft which is bored
to receive it. . By giving a forward or backward notion to this rod by any
convenient mechanism within the ship or boat a reversal of the angle of the blades
of the propeller. will be effected.
The reversal of the angle of the propeller blades (as an alternative plan) may be
accomplished by means of links attached at one end to the reversing rod and at
the other to levers on the shanks of the propeller blades; or by a suitably shaped
cam attached to the reversing rod; operating levers on the shanks of the propeller
blades.
The mode of carrying out this invention will be better understood. by reference
to the accompanying drawings of a two bladed screw propeller, in which
Fig. 1 is a vertical longitudinal section of the propeller boss and of a portion of
the propeller shaft, (the reversing rod or shaft G, the sliding racks F, and a
portion of one propeller blade B not being in section).
=

page_text: Fig. 2 is a horizontal section of the propeller boss, and of a portion of the
propeller shaft, (the reversing rod or shaft G, and the sliding racks F not being
in section).
Fig. 3 is a vertical transverse section on the line Y Z in Figs. 1 and 2, (the
shanks, and portions of the propeller blades not being in section).
The letters of reference denote the same parts in all the figures.
The boss of the propeller is shown at A having holes bored transversely to, and
on opposite sides of the axis of revolution for the reception of the shanks of the
propeller blades C. Portions of the propeller blades are shown at B.
The shanks
of the propeller blades are secured in their places in the boss so as just to revolve
freely, by collars D, (or they may be secured by plates as shown in Fig. 4 of my
former Specification,) and have cut on them at about the centre of their length,
spur segments shown at E. Spur racks F gear into these spur segments and have
attached to them a rod or shaft G arranged to move freely in a longitudinal
direction within the hollow propeller shaft H. Recesses I are formed in the boss
for the reception of hydraulic leathers or other suitable packing J for preventing
the ingress of water.
It will be evident from the foregoing description that by giving a longitudinal
movement to the rod or shaft G by any suitable mechanism within the ship or
boat in one direction will cause the blades of the propeller to assume a reverse
angle to that which they will assume if the rod or shaft G is moved in the opposite
direction.
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
In a reversible screw propeller, the insertion of the shanks of the propeller
blades (the said shanks being of the description shown in my Specification
No. 20194 A.D. 1892) in the boss on opposite sides of the axis of revolution so as
to admit of the mechanism for effecting their reversal passing between them,
substantially as drawn and described.
Dated this 18th day of January 1894.
JAMES STEPHENS.