Improvements in Plural Screw Engines.
Year: 1895

page_text: Date of Application, 9th Nov., 1895
Complete Specification Left, 6th Aug., 1896-Accepted, 26th Sept., 1896
Improvements in Plural Screw Engines.
I, MATTHEW PAUL, of Levenford Works, Dumbarton, in the County of
Dumbarton, North Britain, Engineer, do hereby declare the nature of this invention
to be as follows, that is to say :-
My said invention has for its object improved constructions and arrangements
cf engines for driving plural screws, that is two or more screws fitted to one
steamer.
In carrying out my invention according to one modification in which the parts
are arranged for driving two or three screws, I place three shafts so as in cross
section to be at the corners of a triangle, and with one of them by preference
between and equidistant from the other two and at a higher or lower level. The
middle shaft is driven by any suitable known kind of inverted-cylinder or other
screw engines, working with one or more stages of expansion; and it is connected
to the other two shafts by a triangular frame fitted to cranks on the three shafts,
the crank on the middle or driving shaft being either a separate crank or an
elongation of one acted on by the engines. All three shafts may extend to the
ship's stern and carry screw propellers, or only two may do so. In this arrangement
all three shafts rotate in the same direction.
When it is desired to have two shafts rotating in opposite directions I employ
a second modification in which inverted cylinders are arranged in a vertical fore-
and-aft plane midway between the two shafts which may be geared to each other
if required. Each piston-rod block or crosshead has fitted to it two connecting
rods which diverge and act on cranks one on each shaft, in which arrangement
the transverse strains on the rods balance each other and the direct strains are
equal.
For a steamer of small draught I employ four screws arranged in pairs, and each
pair driven by separate engines the parts and connections being as in either the
first or second modification hereinbefore described.
Dated this Eighth day of November 1895.
TRUM
EDMUND HUNT,
Applicant's Agent.
Improvements in Plural Screw Engines.
I, MATTHEW PAUL, of Levenford Works, Dumbarton, in the County of
Dumbarton, North Britain, Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, that is to say :-
My said invention has for its object improved constructions and arrangements
of engines for driving plural screws, that is two or more screws fitted in one
steamer.
In machinery made according to one modification of my invention, three parallel
shafts work in bearings placed at the angles of an imaginary triangle and have on
them equally long cranks the pins of which are connected by a frame in a manner
Price 8d

page_text: to permit of the shafts revolving. One of the said shafts is driven by any known
kind of screw engines and all or only two of them may carry propellers.
In another modification of my improved machinery inverted-cylinder screw
engines have two connecting rods fitted to each piston rod crosshead and these
connecting rods diverge and act on cranks on two parallel shafts.
And in order that my said invention and the manner of performing the same
may be properly understood I hereunto append two sheets of explanatory drawings,
to be hereinafter referred to, and showing as much of two modifications of my
improved machinery as is necessary to explain my invention.
Figure 1, on Sheet, 1, of the drawings is a plan, and Figure, 2, is a transverse
vertical section of part of one modification.
Figures, 3, and 4, on Sheet, 2, are elevations of another modification as taken
at right angles to each other.
In these drawings the same reference letters are used to mark the same or like
parts wherever they are repeated.
So as
In carrying out my invention according to the modification shown in Figures, 1,
and 2, of the drawings the parts are arranged for driving two or it might be three
screws. Three shafts, A, B, and C, are carried in bearings on the bed-plate
in cross section to be at the corners of a triangle, and with one of them by
preference between and equidistant from the other two and at a higher (or it might
be a lower) level. The middle shaft, B, is driven by any suitable known kind of
inverted-cylinder or other screw engines, working with one or more stages of
expansion; and it is connected to the other two shafts, A, and C, by a triangular
frame, D, made with bearings, E, to fit on the pins of cranks, G, on the three
shafts. The crank, G, of the middle or driving shaft, B, is a separate crank on
that shaft (which is shown in the drawings with two other cranks as suitable for
two-cylinder compound engines) or it might be an elongation of one acted on by
the engines. All three shafts, A, B, and C, may extend to the ship's stern and
carry screw propellers or only two may do so. In this arrangement all three shafts
rotate in the same direction.
When it is desired to have two shafts rotating in opposite directions I employ
a second modification shown in Figures, 3, and 4, in which inverted cylinders, H,
are arranged in a vertical fore-and-aft plane midway between the two shafts, A,
and C, (which may be geared to each other if required). Each piston-rod block
or crosshead, J, has fitted to it two connecting rods, K, which diverge and act on
cranks, G, one on each shaft, A, C, in which arrangement the transverse strains
on the rods balance each other and the direct strains are equal.
For a steamer of small draught I employ four screws arranged in pairs, and
cach pair driven by separate engines, the parts and connections being as in either
the first or second modification hereinbefore described.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In plural screw engines, three parallel propeller shafts having on them
cranks connected by a frame, one of the said shafts being directly driven by
engines, substantially as herein before described with reference to Figures 1, and 2,
of the accompanying drawings.
2. In plural screw engines, fitting to each piston-rod crosshead two divergent
connecting rods acting on separate cranks on two parellel propeller shafts
substantially as hereinbefore described with reference to Figures, 3, and 4, of the
accompanying drawings.
Dated this Fifth day of August 1896.
EDMUND HUNT,
Applicant's Agent,