IMPROVEMENTS IN SCREW PROPELLERS
Year: 1869

page_text: LETTERS PATENT to Restel Ratsey Bevis, of Birkenhead, for the
Invention of "IMPROVEMENTS IN SCREW PROPELLERS."
Sealed the 13th July '1869, and dated the 6th March 1869.
PROVISIONAL SPECIFICATION left by the said Restel Ratsey Bevis
at the Office of the Commissioners of Patents, with his Petition,
on the 6th March 1869.
I, RESTEL RATSEY BEVIS, of Birkenhead, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN SCREW PROPELLERS," to
be as follows:-
In order to be enabled to feather the blades of a screw from within
the ship, so that they may be brought in a line fore and aft, or any
¡utermediate angle, a sliding rod is according to this Invention employed
passing through a hole bored through the centre of the last length of
shaft. The inner end of the sliding. rod is fitted with a cross bar which
passes through. a. slot in the shaft into a recess in a large nut which
embraces the shaft, and works on a screw thread cut on the shaft, and
Price 8d.]

page_text: gives the required motion to the sliding rod. The outer end of the
sliding rod is formed with two bosses, to which are attached two links
which take hold of two short levers fixed in the shanks of the blades,
and the position of the blades is adjusted by moving the bar in or out by
means of turning the nut on the shaft in which the cross bar of the
sliding rod rests. This nut may be moved by podgers or by steam power
working a worm or any convenient method. In place of employing a
screw and nut for moving the sliding rod to and fro other arrange-
ments might be adopted. The shanks of the blades, the levers, and
links are enclosed in the boss of the screw and thus protected from
injury.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Restel Ratsey Bevis in the Great Seal Patent Office
on the 6th September 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RESTEL
RATSEY BEVIS, of Birkenhead, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of March, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
second year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said Restel Ratsey Bevis, Her special
licence that I, the said Restel Ratsey Bevis, my executors, administra-
tors, and assigns, or such others as I, the said Restel Ratsey Bevis, 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 for "IMPROVEMENTS
IN SCREW PROPELLERS," upon the condition (amongst others) that I, the
said Restel Ratsey Bevis, my executors or administrators, by an instru-
ment 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 immediately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Restel. Ratsey, Bevis, do hereby
declare the nature of the said Invention, and in what
2:
manner the
same is to be performed, to be particularly, described, and, as
and, ascertained,
in and by the fallowing statement thereof, that is to say: sloop quit
In order to be enabled to feather the blades of a screw from within
the ship so that they may be brought in a line fore and aft or any inter-
mediate angle, a sliding rod is according to this Invention employed
passing through a hole bored through the centre of the last length or
lengths of shaft. The inner end of the sliding rod is fitted with a cross
bar which passes through a slot in the shaft into a recess in a large nut
which embraces the shaft, and works on a screw thread cut on the shaft,
and gives the required motion to the sliding rod. The outer end of the
sliding rod is formed with two bosses, to which are attached two links
which take hold of two short levers fixed in the shanks of the blades, and
the position of the blades is adjusted by moving a bar in or out by means
of turning the nut on the shaft on which the cross bar of the sliding
rod rests. This nut may be moved by podgers or by steam power
working a worm, or any convenient method. In place of employing a
screw and nut for moving the sliding rod to and fro other arrange
ments might be adopted. The shanks of the blades, the levers, and
links are enclosed in the boss of the screw, and thus protected from
injury.
In the Drawings hereunto annexed is shown a screw propeller con-
structed as above described in such manner that its blades may be set
to any desired angle by the moving endwise of a sliding rod passing
through a hole in the centre of the last length or lengths of the propeller
shaft.
:
Figure 1, Sheet 1, shows a side view partly in section of a screw pro-'
peller constructed as above described; Figure 2 is a transverse section
taken through the central boss of the propeller; Figure 3 is an aft elevation
of the boss with its cap removed; and Figure 4 is an exterior view of
the screw blade and boss complete.
..
:
On Sheet 2 of the Drawings several of the parts are shown
separately. The nature of each of these separate views is written upon
the Drawing.
a is the propeller shaft, it has a passage through it longitudinally
from end to end; b, the boss affixed to its end and carrying two propeller
blades c. As shown at Figures 2 and 4, the shanks c¹ of the blades are

page_text: formed with a collar c², which abuts upon a face formed for it on the
boss, and is so held by a cap made in two parts. Fixed in the shank of
each blade is an arm or lever 3; it passes through slotted openings in
the socket formed in the boss to receive the shank, and by a link dit is
connected to 'the end of the rod e. This rod e passes through the last
length or lengths of the propeller shaft, and is capable of being slid end-
wise two and fro within it. Into a slöt in the opposite end of this rod
is fitted 'the cross bar f, and the ends of the cross bar pass through slots
in the hollow axis of the propeller shaft, and 'are embraced by the two
parts of the nut g, which works on a screw thread on the exterior of the
shaft. When 'the nut is turned by means of podgers or levers entered
into sockets g formed in it, or otherwise, the key, and consequently the
rode, 'are caused to travel along the shaft, and the shanks of the propeller
blades will thus be turned in their sockets, and the propeller blades are so
set at any desired angle to 'the shaft, or 'they are feathered or set in the
fore and aft line. When the blades of the propeller 'have thus been set to
the desired 'angle the nüt can be prevented from shifting by sliding
inwards one of the small bolts h carried by the nut g, so that its end
shall enter the slot through the screw shaft, and so lock the bolt" from
turning. The way in which the nut 'g is made in two parts held
together by screw bolts is clearly shown on Sheet 2. The way in which
the boss is formed to enclose the end of the rode and the links dis
also clearly shown by the Drawing. In place of employing a screw
and nut to move the sliding rod e endwise or longitudinally within the
shaft other arrangements might be adopted as before stated.
In 'witness whereof, I, the said Restel Ratsey Bevis, have here-
unto set my hand and seal, this Fourth day of September, in
the year of our Lord One thousand eight hundred and sixty-
nine.