IMPROVEMENTS IN SCREW PROPELLERS
Year: 1869

page_text: LETTERS PATENT to William Robert Lake, of the "International
Patent Office," No. 8, Southampton Buildings, London, Consulting
Engineer, for the Invention of "IMPROVEMENTS IN SCREW PROPELLERS."
- A communication from abroad by Frederick Wittram, of San
Francisco, California, United States of America.
Sealed the 19th November 1869, and dated the 19th August 1869.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition, on
the 19th August 1869.
I, WILLIAM ROBERT LAKE, of the "International Patent Office,"
No. 8, Southampton Buildings, London, Consulting Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN SCREW
PROPELLERS," a communication, to be as follows:-
My Invention relates to propellers which are used on steamboats or
vessels, and has for its object what may be called reefing or reducing
the area of the resisting surface of the propeller when the vessel is moved
by wind or other power than that applied to the screw shaft without

page_text: resorting to any of the expensive or complicated methods of elevating
the screw now in use.
To accomplish the desired object I construct a screw propeller of any
desired form or pitch in two or more vertical sections perpendicular to
the axis of rotation. In the present instance I will describe a propeller
divided into three parts; one of these is keyed or otherwise fixed to the
shaft, the others are made to work freely upon the said shaft. When
the propeller is to be used to propel the vessel the several parts are
secured together by any convenient means forming a complete screw
propeller. When sails are used and the screw is not required the
sections are disengaged and secured together in a line with each other
presenting a minimum surface of resistance to the passage of the water
aft. The sections in the present instance are secured together in either
of the above-mentioned relative positions by a bolt working in a groove
in the shaft and carrying studs, which when the bolt is forced aft from
the interior of the vessel or in any other convenient manner take into
suitable recesses or notches in the hubs of the sections. When the bolt
is withdrawn to a proper distance the studs enter into annular grooves
in the hubs, which permit the free revolution of the sections in changing
their relative positions.
I do not limit myself to sections of any particular form, nor to the
number of arms or blades or of sections nor to any special devices for
securing the said sections in position.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent 2
Office on the 18th February 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," No. 8, Southampton
Buildings, London, Consulting Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her 3
Letters Patent, bearing date the Nineteenth day of August, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Robert Lake, Her special licence
that I, the said William Robert Lake, my executors, administrators, and 3

page_text: assigns, or such others as I, the said William Robert Lake, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter 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 Invention of "IMPROVEMENTS IN
SCREW PROPELLERS," a communication to me from abroad by Frederick
Wittram, of San Francisco, California, United States of America, upon
the condition (amongst others) that I, the said William Robert Lake,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Robert Lake, 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, reference being had to the accompanying
Drawing, forming a part of this Specification:-
My Invention relates to propellers for steamboats or vessels, and has
for its object what may be called reefing or reducing the area of the
resisting surface of the propeller when the vessel is moved by wind or
other power than that applied to the screw shaft without resorting to
any of the expensive or complicated methods of elevating the screw now
in use.
DESCRIPTION OF THE DRAWING.
Figure 1 is a front view of a two-bladed screw propeller constructed
according to this Invention with parts adjusted for action; Figure 2 is
a side view of the same; Figure 3 is a front view of the said propeller
showing the same adjusted as when not required for propulsion, and
Figure 4 is a side view thereof with parts in like position; Figures 5, 6,
and 7 illustrate the construction of a duplex propeller according to this
Invention; Figure 8 shows a.locking apparatus used in connection with
the said propeller; Figures 9 and 10 illustrate modifications in the
construction of the propeller blades.. Like letters indicate the same parts
throughout the Drawing.

page_text: I construct the screw propeller A of any desired form or pitch and in two
or more vertical sections perpendicular to the axis of rotation, as shown
in Figures 1, 2, 3, and 4, it is divided into three parts, a, b, and c, one
of these is keyed or otherwise fixed to the shaft d; the others are made
to work freely upon the said shaft. When the propeller is to be used to
propel the vessel the several parts a, b, and c are secured together by any
convenient means, and then form a complete screw propeller, as shown
in Figures 1 and 2. When the screw is not required for the propulsion
of the vessel, as, for instance, when sails are used, the sections a, b, and c
are disengaged and secured together in a line with each other, as shown
in Figures 3 and 4, presenting a minimum surface of resistance to the
passage of the water aft. These sections in the propellor illustrated in
Figures 1, 2, 3, 4, are secured together in either of the above-mentioned
relative positions by a bolt e, working in a groove in the shaft d, and
carrying studs i, which when the bolt is forced aft from the interior of
the vessel or otherwise adjusted take into suitable recesses or notches in
the hubs of the said sections. When the bolt is withdrawn to a proper
distance the studs enter annular grooves in the hubs, which grooves
permit the free revolution of the sections in changing their relative
positions.
The duplex propeller is shewn in Figure 5 with the blades in a line
with each other. Both pairs may be either of the same or of a different
pitch, and the said blades may be of any convenient form.
Figure 6 represents the forward screw, and Figure 7 the after one.
In Figure 8 I have shown the rear of the stern post with the locking
apparatus.
In Figures 5 and 8 I have illustrated one form of apparatus by means
of which the blades may be locked in line, as shown, or in a position at
right angles with each other so as to form in effect a four-bladed screw
propeller, and this change can be made from the deck or from the interior
of the vessel with facility and certainty. fis a shaft which is held in posi-
tion by guides at g and h; and is kept from rising or falling by a bearing
or collar working in a box at i. The upper end of the shaft is furnished
with a hand wheel or any convenient means by which it may be
revolved. The lower end of the shaft f is formed into a screw k, which
works in a nut 1, this nut is furnished with trunnions which take into
the ends of the short arms of angular or bell-crank levers m and n.
secured to a bracket jone on each side. These levers may be curved

page_text: outward to embrace a circular clutch o upon the screw shaft d, and
the arms m and n are attached to the clutch by means of trunnions.
Keys or pins q project aft from the rear face of the clutch, and take into
holes through the hub of the forward screw, and enter other openings x
to a sufficient depth in the hub of the after screw. The forward
screw is keyed to the shaft d, and is formed with a sleeve a projecting
aft, upon which the after screw is placed loose and held on by a cap nut
and washer, which is so arranged on the after end of the sleeve as to
prevent the ingress of water between the sleeve or casing and the shaft.
The forward screw has a segmental projections on the after side or face
of its hub, which projection takes into a depression shown at t. Upon
the forward face of the after hub is a segment y arranged to allow a
motion of one upon the other. The projection and depressions and t
are so arranged in relation to the wings or blades, as to permit them
to assume the position shown in Figure 5, or to be adjusted at right
angles with each other to form a four-bladed propeller, as herein-before
stated.
11
In operation the blades being in line as shown in Figure 5, and it
being desired to form the four-bladed propeller, the shaft fis revolved
so as to elevate the nut and with it the arms of the levers causing the
clutch to be moved forward on the shaft d for a sufficient distance to
relieve the after blades, the latter when the vessel is under way will by
the resistance of the water be caused to move on the shaft until the two
segments 8 and y meet, when they are locked or clutched by revolving
the shaft in the opposite direction, forming the four-bladed propeller.
It is obvious that by reversing the order of these operations the blades
will be returned to the first position. The surface of the wings or blades
may be smooth as represented in Figures 1, 2, 3, 4, 5, 6, 7, or I may
make them corrugated either in a direction parallel to the axis of motion
or concentric therewith or in radiating lines straight or curved, the
sections of the said corrugations showing either waved lines, as in
Figure 9, or angular lines as in Figure 10, or a combination of both.
Having thus fully described the said Invention as communicated to
me by my foreign correspondent, I wish it understood that I do not
limit myself to sections of any particular form, or to the number of
blades or sections, or to any special devices for securing the said
sections in position, but I claim,―
First. The propeller A when constructed in two or more sections and

page_text: so arranged in connection with the bolt e or equivalent device that the
sections can be so secured together upon the shaft d as to form a complete
propeller or may be adjusted in a line with each other, substantially as
and for the purposes set forth.
· Second. The apparatus for locking the blades of the duplex propeller
in line with or at a right angle to each other, substantially as and for
the purpose set forth.
Third. Constructing my improved propeller with corrugated blades,
substantially as set forth.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Eighteenth day of February, in
the year of our Lord One thousand eight hundred and seventy.
WILLIAM ROBERT LAKE. (L.S.)
Witness,
H. J. GEDGE,
Clerk to Messrs. Haseltine, Lake, & Co.
8, Southampton Buildings,
London.