IMPROVEMENTS IN SCREW PROPELLERS
Year: 1859

page_text: LETTERS PATENT to Thomas Eastman, of Southsea, in the County of
Hants, Naval Instructor, for the Invention of "IMPROVEMENTS IN SCREW
PROPELLERS." -A communication from abroad by James Shepard, residing
at Buffalo, in the United States.
Sealed the 28th February 1860, and dated the 30th August 1859.
PROVISIONAL SPECIFICATION left by the said Thomas Eastman at the
Office of the Commissioners of Patents, with his Petition, on the 30th
August 1859.
I, THOMAS EASTMAN, of Southsea, in the County of Hants, Naval
Instructor, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN SCREW PROPELLERS," (communicated to me from abroad by James
Shephard, residing at Buffalo, United States,) to be as follows:-
This Invention consists in constructing screw propellers with two or more
blades, by preference four, each being of the form illustrated in the Drawings
hereunto annexed, or of any similar or equivalent form.
Figure 1 of the said Drawings is a side view of a four-bladed propeller
constructed according to this Invention; Figure 2 is a back or end view of
the same; Figure 3 is a section of the blade through the line a, b, of the
blade A, Figure 2; and Figure 4 is a section through the line c, d, of the
same blade. The blades B, C, D, are all similar in form and dimensions to A.

page_text: The Inventor prefers forming the blades separately, and connecting them to
the boss by means of key slots and keys so arranged as to allow the blades to
be set at varying pitches if required.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Eastman in the Great Seal Patent Office on the
29th February 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
EASTMAN, of Southsea, in the County of Hants, Naval Instructor, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirtieth day of August, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Eastman, Her special licence that I, the said Thomas Eastman, my
executors, administrators, and assigns, or such others as I, the said Thomas
Eastman, 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," (communicated to me from abroad by James Shepard, residing
at Buffalo, United States,) upon the condition (amongst others) that I, the
said Thomas Eastman, 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 immediately after
the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Eastman, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the Drawings hereunto annexed,
that is to say:-
This Invention consists in constructing screw propellers with two or more
blades, each being of one of the forms illustrated in the Drawings hereunto
annexed, or of any similar or equivalent form.

page_text: Figure 1 of the said Drawings is a side view of a four-bladed propeller con-
structed according to this Invention; Figure 2 is a back or end view of the
same; Figure 3 is a section of the blade through the line a, b, of the blade A,
Figure 2; and Figure 4 is a section through the line c, d, of the same blade.
The blades B, C, D, are all similar in form and dimensions to A. The
Inventor prefers forming the blades separately, and connecting them to the
boss by means of key slots and keys so arranged as to allow the blades to be
set at varying pitches if required. Figure 5 is a plan of one blade of a pro-
peller also constructed according to this Invention, but of a somewhat modified
form; Figure 6 is a view of the same blade fitted in a socket formed in the
boss on the propeller shaft; and Figure 7 is a side elevation of two blades
fitted in a similar manner with the propeller shaft passing through it. A, A,
are the propeller blades, the shanks or ales B, B, of which are tapered as
shown to fit into the sockets formed in the boss C; D, D, are keys or cotters
passing through the boss and the shank of the blades for holding the latter in
position; E is the propeller shaft.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I claim the construction
of screw propellers with two or more blades, each being of one of the forms
illustrated in the Drawings hereunto annexed, or of any similar or equivalent
form.
In witness whereof, I, the said Thomas Eastman, have hereunto set
my hand and seal, this 27th day of February, One thousand eight
hundred and sixty.
THOMAS EASTMAN, R.N. (L.S.)
THOMAS EASTMAN, R.N. (L.S.)