Im- PROVEMENTS IN SCREW PROPELLERS
Year: 1873

page_text: LETTERS PATENT to Matthew V. Jones, Engineer, of Oystermouth, nº.
Swansea, in the County of Glamorgan, for the Invention of "Im-
PROVEMENTS IN SCREW PROPELLERS.”
Sealed the 16th September 1873, and dated the 23rd July 1873.
PROVISIONAL SPECIFICATION left by the said Matthew V. Jones at
the Office of the Commissioners of Patents, with his Petition, on
the 23rd July 1873.
I, MATTHEW V. JONES, Engineer, of Oystermouth, nr. Swansea, in
the County of Glamorgan, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN SCREW PROPELLERS," to be as follows:
-
My Invention consists of improvements in screw propellers whereby
slip is lessened and vibration completely prevented, for which purpose
I construct my propellers with shields or rims, either cast on or fitted to
the screw blades, which considerably strengthen them, and at the same
time prevent ropes, wreckage, or floating debris of any description
striking against and thereby injuring or breaking the blades. The grip

page_text: is also considerably increased, thus giving the propellers greater hold on
the water while steaming head to sea & wind, and of course greater
speed is obtained.
I prefer to construct my propellers with four blades, and make the
bosses as small as possible compatible with strength, but do not confine
myself to any number or shape of blades.
These propellers can be worked at full speed amongst hawsers, chains,
nets, ice, or any other debris without fouling.
The risk of break down to engines and machinery is also lessened, &
the engines running away prevented by the self-governing action of the
propeller, and by its easy action the wear in the stern tube is con-
siderably reduced.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Matthew V. Jones in the Great Seal Patent Office
on the 20th January 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MATTHEW
V. JONES, Engineer, of Oystermouth, n'. Swansea, in the County of
Glamorgan, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria by Her Letters
Patent, bearing date the Twenty-third day of July, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Matthew V. Jones, Her special license
that I, the said Matthew V. Jones, my executors, administrators, and
assigns, or such others as I, the said Matthew V. Jones, 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
IN SCREW PROPELLERS," upon the condition (amongst others) that I, the
said Matthew V. Jones, 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 Inven-

page_text: tion, 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.
4
NOW KNOW YE, that I, the said Matthew V. Jones, 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 thereof, that is to say:
-
My Invention of improvements in screw propellers consists in con-
structing them with a shield or rim at the periphery, by which means
slip is lessened and vibration prevented, as there is no radial dispersion
of the water, so that more effect is produced, greater speed obtained,
and there is less strain on the machinery than is the case when the same
amount of power is applied to ordinary propellers, besides which my
propeller is considerably strengthened by connecting the outer ex-
tremities of the arms or blades, and is less liable to injury as the 'shield
protects the arms or blades from becoming enveloped or fouled by coming
in contact with ropes, wreckage, or floating debris of any description.
It may also be made considerably lighter than ordinary propellers.
I am enabled by my improvements to construct propellers with small
bosses, thereby ensuring better castings than is possible when there is
so great a difference in thickness between the metal of the boss and the
blades. The blades also being supported at both ends all strains are
distributed throughout the whole of the propeller instead of being con-
centrated at the junction of the blade with the boss.
I prefer to construct my propeller with four blades, but my improve-
ments are equally applicable to propellers constructed with three or any
other number of blades.
I do not confine myself to any particular form or angle of pitch, but
prefer the angle of blade at the boss to be about 70°, at the middle of
blade 45°, and at the periphery 30°; length of boss one-sixth diameter of
propeller; blade to be the same length as the boss. I prefer the width
of the shield not to exceed one-half the length of the boss. The shield
may either be cast on to the blades or bolted to them.
In order that my Invention may be better understood and more
readily carried into operation, I will now proceed to describe the
Drawings hereunto annexed.

page_text: Figure 1 is a front elevation shewing the shield or rim connected to
the arms at their outer extremities; Figure 2 is a side elevation shewing
width of the shield and length of the boss; Figure 3 is a section through
the arms shewing the distribution of the metal in the boss arms and
rim; Figure 4 is a section through the boss and rim, with dotted lines
shewing the angle of the blades at different parts of their width;
Figure 5 are sections taken through the blades at various parts of their
width, as indicated by the letters A, A, B, B, C, C, and D, D, on the
front élevation.
Having now particularly described and ascertained the nature of my 1
said Invention, and how the same is to be carried into operation, I would
have it understood that what I claim and desire to secure by the herein-
before in part recited Letters Patent is, the construction of screw pro-
pellers with shields or rims either cast with or bolted to the blades for
the purpose of strengthening the propellers and preventing fouling, as 1
described and illustrated by the accompanying Drawings.
In witness whereof, I, the said Matthew V. Jones, have hereunto
set my hand and seal, this Sixteenth day of January, in the year
of our Lord One thousand eight hundred and seventy-four.
MATTHEW V. JONES. (L.S.)
"
"Engineer."