Improvements in Five-crank Engines.
Year: 1897

page_text: Date of Application, 27th Nov., 1897
Complete Specification Left, 26th Sept., 1898-Accepted, 26th Nov., 1898
Improvements in Five-crank Engines.
I, THOMAS MUDD, of the Central Marine Engine Works, West Hartlepool, in the
County of Durham, Engineer, do hereby declare the nature of this invention to be
as follows:-
In the Specification of a previous Patent No. 1771 of 1895, I have described and
claimed triple, quadruple and quintuple expansion engines with five cranks, and
my present invention has reference to such engines.
I have found that although in a five crank engine in which the cranks are all
at some angle with each other, by making the angles equal and by making the
weights of the reciprocating parts equal to each other, I have been able to attain
stable equilibrium of the working parts with the crank shaft standing in any
position, and practically perfect balance with regard to vertical re-action of the
reciprocating parts, yet that, in such an engine, there is not perfect balance with
regard to those stresses which set up longitudinal rock in the engine, and which
also have (in the case of a marine engine) some bearing on vibratory movements of
a ship.
Now my present invention has reference to a construction of engine in which
there is practically perfect balance of the reciprocating and centrifugal weights
and consequently of the stresses which, set up longitudinal rock and other vibra-
tions in the engine. For this purpose I construct a five crank multiple expansion
engine in which the various moving parts are so combined and arranged and the
relative weights of such parts su determined and disposed that the inertia forces
of the moving parts, for all practical purposes, exactly counteract and nullify each
other in every direction in a central longitudinal plane both with respect to the
moving weights of the main driving parts and also those of the valve gears, whilst
preserving the ordinary and useful condition of having the various important
working parts such as the piston rods, connecting rods, &c. all alike throughout
the engine and consequently interchangeable. And in order that my invention
may be understood 1 will proceed to more fully explain the same by aid of the
accompanying drawings which show, by way of example, so much of a five crank
quadruple expansion engine embodying my invention as is necessary to the under-
standing thereof Fig. 1 being a front elevation, Fig. 2 an end elevation and Fig. 3 a
plan of the engine.
The engine cylinders are arranged in a single row the centres of the five cylinders
being at equal distances apart. The first and second stage cylinders A and B are
arranged at the respective sides of the third stage cylinder C the centre line of
which is the centre of the entire engine, and the two fourth stage cylinders D
The crank shaft has
and E are arranged at the outer ends of the engine.
five cranks F. G, H, J and K connected respectively to the pistons A B C D¹
and E of the cylinders A, B, C, D and E respectively by connecting rods A2 B2
CD and E and piston rods A³ ³ ³ ³ and E³, the connecting rods being of

page_text: equal weight and dimensions, as also are the piston rods, and the five cranks being
so placed that as seen in an end view of the shaft they appear as three cranks
spaced at equal angles, the cranks F and G being in line with each other, and
the cranks and K being also in line with each other. A, B, C, D, E, are the
slide valves of the cylinders A, B, C, D, and E respectively, ( being arranged at
the side of the cylinder and the others being arranged between the cylinders
as shown.
The valve gears L, M for the valve D and E of cylinders 1) and E respectively
are equi-distant from the centre line of the cylinder C, as are also the valve gears 0
and N for the valves A and B of the cylinders A and B. The valve gear P for
the valve of the central cylinder is in the same transverse plane as the axis
of the cylinder itself, and is therefore centrally arranged in a longitudinal plane
and can have no effect in producing endwise rocking of the engine.
The combined weight of the valve A and valve gear 0 attached thereto is
the same as the combined weight of the valve 14 and valve gear Nattached to
that valve; the combined weight of the valve D+ and gear L attached thereto is the
same so is the combined weight of valve E and its gear M. By making the valve
gears L, M, O, N, of the same design as that of the centre cylinder the various parts
of all the five valve gears may be duplicates. When made as shown in the drawing
the parts of gears L M O N are all duplicates.
The weight is the same of the reciprocating parts acting on each of the
cranks F, G, J, and K, that is to say the combined weight of the piston A¹, piston
rod A and crosshead with half the weight of the connecting rod A² which acts on
crank F is the same as that acting on each of the cranks G, J, and K.
The weight of the reciprocating parts acting on the central crank Heiz. the
combined weight of the piston C, piston rod C, and crosshead with half the
weight of the connecting rod C, and half the weight of the valve levers attached
thereto when the corresponding valve C is driven by the connecting rod (as in
the example shown), is made equal to that acting on any two of the other cranks
combined, by concentrating the whole difference in weight upon the piston
itself of the central cylinder C. The cylinders A, B and C, in the example illus-
trated, are lengthened sufficiently to allow of their pistons being made of such
lengths that, notwithstanding the difference in their diameters, the weights of the
pistons in A and B shall be equal to each other and to that of the pistons in the low
pressure cylinders.
The centrifugal weights, viz. the combined weight of the crank webs, the crank
pin, and the lower half of the connecting rod attached thereto is the same in
the case of each of the cranks F, G, J, and K but the centrifugal weights of the
corresponding parts of the central crank H. are made equal in the aggregate to the
centrifugal weights of any two of the other cranks combined, the whole difference
in weight being concentrated in the webs of the crank H. These webs are also
proportioned to balance the centrifugal weights of the sheaves and straps and
lower ends of the eccentric rods L', ' and N of the valve gears L, M, O, N
respectively, either by the addition to the ends of the webs opposite to the crank
pin, of metal the centrifugal effect of which is equal to the centrifugal effects of
any two of the sets of sheaves, straps and lower ends of the eccentric rods, or by
reduction of the weight on the same ends of the webs as the crank pin to an extent
corresponding to the centrifugal effects of any two of the sets of parts referred to.
By thus apportioning the reciprocating and centrifugal parts in connection with
the several cranks, the piston rods, crossheads and connecting rods throughout
the engine can be made duplicates of each other, whilst providing for perfect
balance along the longitudinal central plane of the engines and symmetrically
about a central transverse plane through engine C both with respect to inertia
efforts of main working parts and of the valves and valve gears.
As will be obvious my invention may be applied to multiple expansion engines
other than quadruple engines for example triple and quintuple engines, and that
the cylinders may be arranged in two rows instead of in a single row, and in a

page_text: different order to that herein before described and shown, in the accompanying
drawings.
Dated this 27th day of November 1897.
Improvements in Five-crank Engines.
We, GEORGE HENRY BAINES, of Bradgate, West Hartlepool, in the County of
Durham, Shipbuilder, GEORGE JONES, of Greylands, West Hartlepool, aforesaid,
Shipbuilder, THOMAS EDWIN GOODWIN, of Grange Road, West Hartlepool, Banker,
THOMPSON HOWLETT, of Union Road, Leamington, H.M. Inspector of Schools, and
ELIZABETH MARY MUDD, of Greencliffe, Hartlepool, Widow, Executors of the late
Thomas Mudd, of the Central Marine Engine Works, West Hartlepool, in the
County of Durham, 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:-
-
In the Specification of a previous Patent No. 1771 of 1895, there are described
and claimed triple, quadruple and quintuple expansion engines with five cranks,
and the present invention has reference to such engines.
It has been found that although in a five crank engine in which the cranks
are all at some angle with each other, by making the angles equal and by making
the weights of the reciprocating parts equal to each other, stable equilibrium of the
working parts with the crank shaft standing in any position can be obtained and
practically perfect balance with regard to vertical re-action of the reciprocating
parts, yet that, in such an engine, there is not perfect balance with regard to those
stresses which set up longitudinal rock in the engine, and which also have (in
the case of a marine engine) some bearing on vibratory movements of a ship.
Now the present invention has reference to a construction of five crank multiple
expansion engine in which there is practically perfect balance of the reciprocating
and centrifugal weights and consequently of the stresses which set up longitudinal
rock and other vibrations in the engine. For this purpose the various moving
parts of the engine are so combined and arranged and the relative weights of such
parts so determined and disposed that the inertia forces of the moving parts, for
all practical purposes, exactly counteract and nullify each other in every direction
in a central longitudinal plane both with respect to the moving weights of the main
driving parts and also those of the valve gears, whilst preserving the ordinary
and useful condition of having the various important working parts such as the
piston rods, connecting rods, &c., all alike throughout the engine and consequently
interchangeable. And in order that the invention may be fully understood we
will proceed to more fully explain the same by aid of the drawings filed with the
Provisional Specification which show, by way of example, so much of a five crank
quadruple expansion engine embodying the present invention as is necessary to
the understanding thereof, Fig. 1 being a front elevation, Fig. 2 an end elevation,
and Fig. 3 a plan of the engine.
The engine cylinders are arranged in a single row the centres of the five cylinders
being at equal distances apart. The first and second stage cylinders A and B are
arranged at the respective sides of the third stage cylinder C the centre line of
which is the centre of the entire engine, and the two fourth stage cylinders D
and E are arranged at the outer ends of the engine. The crank shaft has

page_text: five cranks F, G, H, J and K connected respectively to the pistons A, B, C, D,
and E of the cylinders A, B, C, D and E respectively by connecting rods A, B²,
CD and E2 and piston rods A, B, C, D and E3, the connecting rods being of
equal weight and dimensions, as also are the piston rods, and the five cranks being
so placed that as seen in an end view of the shaft (Fig. 2) they appear as three cranks
spaced at equal angles, the cranks F and G being in line with each other, and
A, B, C, D, E, are the
the cranks and being also in line with each other.
slide valves of the cylinders A, B, C, D, and E respectively, C being arranged at
the side of the cylinder C and the others being arranged between the cylinders
as shown.
The valve gears L, M, for the valve D and E of cylinders D and E respectively
are equi-distant from the centre line of the cylinder C, as are also the valve gears (
and N for the valves A+ and 13 of the cylinders A and B. The valve gear P' for
the valve C of the central cylinder C is in the same transverse plane as the axis
of the cylinder itself, and is therefore centrally arranged in as longitudinal plane
and can have no effect in producing endwise rocking of the engine.
The combined weight of the valve A and valve gear attached thereto is
the same as the combined weight of the valve B and valve gear Nattached to
that valve; the combined weight of the valve D and gear L attached thereto is the
same; so is the combined weight of valve E and its gear M. By making the valve
gears L, M, O, N, of the same design as that of the centre cylinder the various parts
of all the five valve gears may be duplicates. When made as shown in the drawing
the parts of gears L M N are all duplicates.
The weight is the same of the reciprocating parts acting on each of the
eranks F, G, 1., and K, that is to say the combined weight of the piston A'. piston
rod A and crosshead with half the weight of the connecting rod A which acts on
crank Fis the same as that acting on each of the cranks G, J and K.
The weight of the reciprocating parts acting on the central crank Hiz. the
combined weight of the piston C, piston rod C³, and crosshead with half the
weight of the connecting rod C, and half the weight of the valve levers attached
thereto when the corresponding valve C is driven by the connecting rod (as in
the example shown), is made equal to that acting on any two of the other cranks
combined, by concentrating the whole difference in weight upon the piston (1
itself of the central cylinder C. The cylinders A, B and C, in the example illus-
trated, are lengthened sufficiently to allow of their pistons being made of such
lengths that, notwithstanding the difference in their diameters, the weights of the
pistons in A and B shall be equal to each other and to that of the pistons in the low
pressure cylinders.
The centrifugal weights, is the combined weight of the crank webs, the crank
pin, and the lower half of the connecting rod attached thereto is the same in
the case of each of the cranks F, G, J, and K but the centrifugal weights of the
corresponding parts of the central crank H, are made equal in the aggregate to the
centrifugal weights of any two of the other cranks combined, the whole difference
in weight being concentrated in the webs of the crank H. These webs are also
proportioned to balance the centrifugal weights of the sheaves and straps and
lower ends of the eccentric rods L', M³, 0, and N of the valve gears L, M, O, N
respectively, either by the addition to the ends of the webs opposite to the crank
· pin of metal the centrifugal effect of which is equal to the centrifugal effects of
any two of the sets of sheaves, straps and lower ends of the eccentric rods, or by
reduction of the weight on the same ends of the webs as the crank pin to an extent
corresponding to the centrifugal effects of any two of the sets of parts referred to.
By thus apportioning the reciprocating and centrifugal parts in connection with
the several cranks, the piston rods, crossheads and connecting rods throughout
the engine can be made duplicates of each other, whilst providing for perfect
balance along the longitudinal central plane of the engines and symmetrically
about a central transverse plane through engine C both with respect to inertia
efforts of main working parts and of the valves and valve gears.

page_text: As will be obvious the invention can be applied to multiple expansion engines
other than quadruple engines for example triple and quintuple engines, and that
the cylinders may be arranged in two rows instead of in a single row, and in a
different order to that hereinbefore described and shown in the drawings.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what
we claim is: -
1. A five-crank triple, quadruple, or quintuple expansion engine, having the
combination and arrangement of parts, and the relative disposition and relative
weights of parts, substantially as herein before described with reference to and
shown by the example of a quadruple expansion engine, whereby the inertia forces
of the moving parts of the engine, for all practical purposes, exactly counteract
and nullify each other in every direction in a central longitudinal plane both with
respect to the moving weights of the main driving parts and also those of the valve
gears, whilst preserving the ordinary and useful condition of having the various
important working parts such as the piston rods, connecting rods, &c., all alike
throughout the engine and interchangeable.
2. A five crank engine comprising five cylinders having their pistons working
onto the respective cranks and five distributing valves and sets of valve gear, the
distributing valve and valve gear of the centre cylinder being arranged in the
central transverse plane of the engine containing the axis of the centre cylinder
and the valves and valve gear of the remaining cylinders being arranged syminetric-
ally two on each side of said central plane, substantially as described for the purpose
specified.
3. In a five-crank engine having its cranks set in the positions described and
shown, effecting a balance of the inertia forces by adjustment of the weights of the
pistons alone so far as reciprocating parts are concerned, and of the crank webs
alone so far as the centrifugal parts are concerned so as to enable all other recipro-
cating and centrifugal parts to be made duplicates respectively of each other
throughout the engine as set forth.
4. The improved five crank quadruple expansion engine constructed, arranged
and operating as hereinbefore described and with reference to and shown in the
drawings.
W. LLOYD WISE,
4. Lincoln's Inn Fields. London, W.C.. Chartered Patent Agent.