Improvements in Screw Propellers.
Year: 1888

page_text: Date of Application, 24th Dec., 1888
Complete Specification Left, 24th Sept, 1889-Accepted, 26th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Screw Propellers.
1 JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this invention which has been communi-
cated to me from abroad by La Société Salomon frères et Tenting of 48 rue de
Bondy Paris in the Republic of France, to be as follows:-
This invention relates to improvements in screw-propellers and enables them to be
slowed stopped or reversed by action exerted directly on the propeller and not
affecting the working of the engine. With this object the propeller blades are made
capable of rotating within certain limits on their own axes that is to say on axes
perpendicular to the axis of the propeller shaft and means are provided for rotating
the propeller blades on theso axes so as to vary or reverse the angle at which they
act on the water or cause their surfaces to coincide with the plane of rotation.
The blades may be connected to the boss by a neck or journal on each blade
working in a nut or socket screwed into the side of the boss. This socket may be
made in two parts to facilitate the introduction of the neck. The inner end of the
journal is provided with a head or enlargement carrying a pin or stud arranged
eccentrically to the axis of rotation of the blade.
Within the triangle formed by the meeting of the three heads in the case of a
three bladed propeller for example there is a triangular block capable of sliding in
the direction of the axis of the propeller shaft being provided at one extremity with
a round pin or extension provided with a head or collar capable of engaging with the
fork of the lever or device employed for operating it. Each of the flat sides of this
triangular block facing the heads on the propellers is provided with an inclined groove
or slot engaging with the pin on the corresponding head.
The triangular block is in the centre of the boss and rotates therewith and when
by means of a forked lever for example acting on the rounded part of the block this
latter is moved in the direction of the axis of the propeller shaft the inclined slots or
grooves in the sides of the block act upon the eccentric pins on the heads of the
journals carrying the blades so as to cause the latter to rotate on their axes and
change the angle which they make with the plane of rotation. The amount of this
angular motion of the blades on their own axes is evidently dependent on the amount
of longitudinal displacement of the triangular block. The angle of or inclination of
the slots or grooves and the position of the eccentric pins may be regulated according
to the amount of displacement to be imparted to the blades.
By shifting the block in the direction of the axis of the propeller it is evident that
the blades can be caused to rotate on their own axes so as to vary and even reverse
the angle at which they strike the water so as to cause them to act in either direction
as regards their propelling action or by placing their surfaces in the plane of rotation
their propelling action can be neutralised. By these means the speed can be regulated
and the action of the propeller reversed or suspended entirely independently of the
engine. In place of the triangular block employed in the example herein before
described the block may have four or other number of sides according to the number
of blades in the propeller.
Dated this 24h D
1000
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.

page_text: COMPLETE SPECIFICATION.
Improvements: in Screw Propellers.
I JAMES YATE JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention. (which has been communi-
cated to me from abroad by La Société Salomon frères et Tenting of 48 rue de
Bondy Paris in the Republic of France Engineers) and in what manner the same
is to be performed to be particularly described and ascertained in and by the following
statement:-
This Invention relates to improvements in screw propellers and enables the vessel
to be slowed stopped or reversed by action exerted directly on the propeller and not
affecting the working or rate of speed of the engine. With this object the propeller
blades are made capable of rotating within certain limits on their own axes that is to
say on axes perpendicular to the axis of the propeller shaft and means hereinafter
described are provided for rotating the propeller blades on these axes so as to vary or
reverse the angle at which they act on the water or to cause their surfaces to coincide
with the plane of rotation.
And in order that the said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying drawings represents partly in section the central
part of a screw propeller constructed according to this invention. Figure 2 shows
one blade in elevation partly in section. Figures 3 and illustrate partly in section
the construction of the boss with the parts in different positions and Figure 5
illustrates in perspective the part by which the inclination of the blades is modified
as hereinafter explained. Each blade B is connected to the boss A by a neck or
journal on each blade working in a socket R screwed into the side of the boss. This
socket R may be made in two parts to facilitate the introduction of the neck and
engage with the shoulder U and head S on the blade which is attached to the boss
by placing the socket on the neck and screwing the socket into the boss. All the
blades are connected in the same manner to the boss A which is keyed on the end of
the propeller shaft C. The inner ends of the journals are provided with heads or
enlargements S carrying pins or studs E arranged eccentrically to the axis of the
blades.
Within the triangle formed by the meeting of the three heads S in the case of a
three bladed propeller for example there is a triangular block T capable of sliding in
the direction of the axis of the propeller shaft being provided at one extremity with
a round part or extension D provided with a head or collar capable of engaging with
the fork of the lever or device employed for controlling the position of the blades by
displacing the block T in the direction of the axis of the shaft as hereinafter described.
Each of the flat sides of this triangular block facing the heads on the propellers is
provided with an inclined slot or groove F engaging with the pin E on the corre-
sponding head. These grooves are all of the same form having the same position
and angle on each side of the block (fig. 5).
The triangular block in the centre of the boss is capable of sliding in the direction
of the axis of the shaft or in the direction of the line x-x Figure 5 and at the same
time rotates with the shaft. When by means of a forked lever for example acting on
the rounded part D of the block T this latter is moved in the direction of the axis of
the propeller shaft the inclined slots or grooves F on the sides of the block act upon the
eccentric pins E on the heads of the journals carrying the blades so as to cause the
latter to rotate on their axes (i.e. on the line y-y Figure 2) and change the angle
which they make with the plane of rotation of the propeller. The amount of this
angular motion of the blades on their own axes is evidently dependent on the 'amount
of longitudinal displacement of the triangular block and on the relative position of
the pins E on the heads S. The angle or inclination of the slots or grooves F and

page_text: the position of the eccentric pins E on the heads S is regulated according to the
amount of angular displacement to be imparted to the blades by a given rectilinear
movement of the block T.
The action of this improved arrangement is as follows. The shaft C Figure 3
which is driven directly from the motor is assumed to rotate continuously in the same
direction and with the same speed. The boss A being fixed on the taper part V of
the shaft rotates with the latter and carries with it the prism or block T Figure 3
which is a section showing one side of the block in full the corresponding blade B
being removed and shows the pin E in section in the position E¹ in the groove. In
this figure the block T is represented as having been moved to its extreme position
inwards or to the left hand in the drawing. When in this position the blades of the
propeller are adjusted for giving full speed ahead. Figure 4 shows the parts in the
reverse position the prism or block T being drawn out or moved to the end of its
stroke to the right hand in the drawing. This position of the block causes the
propeller blades to rotate on their own axes and assume a position in which they
drive the vessel full speed astern the pin E being displaced from E¹ Figure 3 to E³
Figure 4 and the blade caused to rotate on its axis through the angle B¹O E³. The
prism or block T and the blades B can be retained in any intermediate position
between the two extreme positions indicated in Figures 3 and 4 and when about
half way between these two positions the blades are feathered so that they do not tend
to move the vessel either ahead or astern.
By these means the speed of the vessel can be changed and regulated as required
without changing the speed of the engine, this heing accomplished by simply varying
the angle or inclination of the blades relatively to the axis of the propeller shaft.
This result is of great value as in certain cases changes in the speed of the engine
are prejudicial to its proper working and preservation.
In the case of a propeller with two or four blades a block having four sides is
employed in place of the triangular block or prism hereinbefore described and
illustrated in the drawing. Antifriction rollers may be arranged to work in the
inclined slots or grooves F in place of the pins E.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. The improvements in screw propellers whereby the speed of propulsion is
enabled to be changed substantially as herein before described and illustrated in the
accompanying drawings.
2. In the construction of screw propellers enabling the rate of speed of the vessel
to be changed without altering the speed of the motor the arrangement for changing
the inclination of the blades of the propeller by the siiding motion of a triangular
or other block partaking of the rotary notion of the shaft substantially as herein-
before described and illustrated in the accompanying drawings.
3. In the construction of screw propellers enabling the rate of speed of the vessel
to be changed without altering the speed of the engine the coinbination of a sliding
triangular or other block with propeller blades capable of being rotated on their own
axis by means of a stud or pin sliding in a slot or groove in the said block substantially
as hereinbefore described and illustrated in the accompanying drawings.
4. In the construction of screw propellers enabling the rate of speed of the vessel
to be changed without altering the speed of the engine the combination of a boss
fixed on the extremity of the driving shaft, propeller blades capable of rotating in
the said boss and studs or pins attached to the blades and working in slots or grooves
in a sliding block substantially as hereinbefore described and illustrated in the
accompanying drawings.
Dated this 24th day of September 1889