IMPROVEMENTS IN STEAM ENGINES, ESPECIALLY APPLICABLE TO SCREW PROPULSION
Year: 1856

page_text: LETTERS PATENT to Joseph Maudslay, of Lambeth, in the County of
Surrey, Engineer, for the Invention of "IMPROVEMENTS IN STEAM ENGINES,
ESPECIALLY APPLICABLE TO SCREW PROPULSION."
Sealed the 27th January 1857, and dated the 20th August 1856.
PROVISIONAL SPECIFICATION left by the said Joseph Maudslay at the
Office of the Commissioners of Patents, with his Petition, on the 20th
August 1856.
I, JOSEPH MAUDSLAY, of Lambeth, in the County of Surrey, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN STEAM
ENGINES ESPECIALLY APPLICABLE TO SCREW PROPULSION," to be as follows:-
This Invention consists in modification of and improvements on the annular
cylinder engine (patented by me on the 16th March 1841), intended to adapt
that Invention to purposes of screw propulsion. The present improvements
consist in placing the annular cylinder above the crank shaft instead of below
it, as described in the Specification of my aforesaid Patent of 1841, and in
connecting the piston rod cross-head with the crank of the crank shaft, by
means of a connecting rod passing.from the piston rod cross-head downwards
through the central or inner cylinder to the crank shaft below the cylinder:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Joseph Maudslay in the Great Seal Patent Office on the
20th February 1857.
:
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPII
MAUDSLAY, of Lambeth, in the County of. Surrey, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twentieth day of August, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Joseph Maudslay, Her especial licence that I, the said Joseph Maudslay, my
executors, administrators, and assigns, or such-others as I, the-said Joseph
Maudslay, 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
STEAM ENGINES, ESPECIALLY APPLICABLE TO SCREW PROPULSION," upon the condition
(amongst others) that I, the said Joseph Maudslay, my executors or admi-
nistrators, 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 Joseph Maudslay, do hereby declare the
nature of my 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 annexed, (that is
to say):
This Invention consists in making a firm and compact arrangement of
marine steam engine intended for the purpose of screw propulsion, by placing
an annular cylinder immediately above the crank shaft, and communicating the
power from the piston rod cross-head above the cylinder to the crank, by
means of a connecting rod passing downwards through the central or inner
cylinder.
Figure 1 of the Drawings annexed is a front elevation, partly in section, of
a pair of coupled engines, shewing these improvements as intended for screw
propulsion; Figure 2 is a side view of these engines in section; Figure 3 is
a side elevation, and Figure 4 is a plan, one-half of which is shewn partly in

page_text: section with the cylinder removed. A is the annular cylinder; B, piston rod
cross-head, to which the two piston rods C, C, are connected; D, D, the guide
for the cross-head; E, the connecting rod, working through the inner cylinder F,
and communicating the power from the piston rod cross-head to the crank G.
This arrangement of engine is proposed to be used more especially in com-
mercial steam vessels, where it is not necessary to keep the machinery entirely
below the water line, and its advantages consist,-
Firstly, in having the cylinder placed upright directly over the crank shaft,
and supported on short standards cast on the condenser, or bed plate, thus
forming a very rigid and firm combination in itself, and not requiring any
connections from the vessel to steady it.
Secondly, in having the piston rod glands and cross-head guides on the top
of the cylinder cover, where they are more easily attended to than when
placed horizontally or below the cylinder; and also in having all the joints and
moving parts of the engine arranged so that they can be conveniently got at
for the purpose of oiling, which is of great importance in engines working at a
great velocity, in order that they may be kept in good condition.
And, thirdly, in this arrangement a much longer connecting rod is obtained
than in ordinary engines, in consequence of which the side thrust on the cross-
head guides is considerably reduced.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that I claim, the arrangements
of annular cylinder engines, herein-before described, and represented in the
Drawings annexed, whereby they are particularly adapted to the purposes of
screw propulsion.
In witness whereof, I, the said Joseph Maudslay, have hereunto set my
hand and seal, this Twelfth day of February, One thousand eight
hundred and fifty-seven.
JOSEPH MAUDSLAY. (L.S.)
JOSEPH MAUDSLAY. (L.S.)