Improvements relating to the Balancing of Steam and like Engines.
Year: 1895

page_text: Date of Application, 16th Feb., 1895
Complete Specification Left, 16th Nov., 1895-Accepted, 21st Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements relating to the Balancing of Steam and like Engines.
1, JOHN TWEEDY, of Neptune Works, Newcastle-on-Tyne, Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention relates to the balancing of steam and like engines having three
or more cylinders working on one crank shaft, and has for its object the production
of a perfect or nearly perfect balance without the use of balance weights either
reciprocating or rotary, or with relatively small balance weights, by suitably
proportioning the weights of the reciprocating parts and of the cranks, and by
suitably arranging the angles of the cranks and positions of the cylinders. I am
aware that it has been proposed in the prior Specification of Otto Schlick No. 2913
of 1894 to balance in this manner engines whose cylinders are in the same plane
or substantially in the same plane, but I have found that the principle underlying
that invention can be extended to engines whose cylinders are not in the same
plane and this constitutes the feature of my invention.
-
In constructing an engine according to my invention I determine the components
in the plane in which it is intended to have the engines as a system balanced-
of the reciprocating weights of the cylinders not in the aforesaid plane and I
arrange these components, together with such reciprocating weights as may be
actually in that plane, and the distances between the centres of the cylinders, and
the angle and length of the cranks in the manner described in the Specification
No. 2813 of 1894 for cylinders in the same plane so as to ensure a balance or any
desired approximation thereto.
Dated this 16th dow of Fahy 1205
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements relating to the Balancing of Steam and like Engines.
I, JOHN TWEEDY, of Neptune Works, Newcastle-on-Tyne, 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:-
This invention relates to the balancing of steam and like engines having three
or more cylinders working on one crank shaft, and has for its object the production
of a perfect or nearly perfect balance without the use of balance weights either
reciprocating or rotary, or with relatively small balance weights, by suitably
proportioning the weights of the reciprocating parts and of the cranks, and by
suitably arranging the angles of the cranks, and positions of the cylinders or
distances between the cranks.
I am
aware that it has been proposed in the
Specification of Letters Patent No. 2813 of 1894 granted to Otto Schlick to
balance in this manner engines whose cylinders are in the same plane or
substantially in the same plane, but I have found that the principle underlying
D037

page_text: that invention can be extended to engines whose cylinders are not in the same
plane, and this constitutes the feature of my invention.
In constructing an engine according to my invention I ascertain the components
in the plane in which it is intended to have the engines as a system balanced--
of the reciprocating weights of the cylinders not in the aforesaid plane and I
arrange these components, together with such reciprocating weights as may be
actually in that plane, and the distances between the centres of the cylinders, and
the angles and lengths of the cranks in the manner described in the Specification
aforesaid for cylinders in the same plane so as to ensure a balance or any desired
approximation thereto.
To describe my invention further in detail let it be supposed that it is intended
to balance an engine in a vertical plane passing through the axis of the crank shaft
and that for reasons which frequently occur in practice the axis of one or more of the
cylinders does not lie in this plane. Let Figure 1 represent diagrammatically a
cylinder with its piston, piston rod connecting rod and crank, the cylinder being
vertically above the crank shaft, and let Figure 2 represent diagrammatically one
of the inclined cylinders with its piston, piston rod, connecting rod and crank.
AB Figure 2 is the vertical plane in which the engine is to be balanced, A. C the
axis of the cylinder lying at an angle to the vertical plane.
The reciprocating weights of this engine tend to displace it in the direction of
the axis A C, with a force which may be expressed by F cos ; where F
P
=
=
P v³
9 Ri
weight of reciprocating parts; v = constant velocity of crank pin in feet
per second; R: = radius of crank in feet; g = acceleration due to gravity; and
the angle between the crank and the axis A C at the moment under
consideration. The force F cos o acting at any instant along the axis AC may
be resolved into a vertical component acting in the plane A B and a horizontal
component at right angles to the plane A B. The vertical component is F cos
cos 0. I therefore inake P and of such magnitudes that a weight equal to P
cos acting vertically on a crank inclined at an angle to the crank of the
inclined engine would be the required weight and position of crank to ensure a
balance vertically as described by Mr. Schlick in the Specification No. 2813
A.D. 1894. Or the desired result may be obtained by the converse process.
Having determined the weights and other elements necessary for a balance as
described by Mr. Schlick in the aforesaid Specification any cylinder may be
inclined at an angle 0. to the vertical plane provided (1) the corresponding crank
be moved in relation to the other cranks through the same angle in the same
direction as the cylinder, and (2) the reciprocating weights be altered in the
following ratio
Weights of reciprocating parts of vertical cylinder
cos
It follows also that if the cylinders make equal angles with the vertical, the
engine may be balanced on the supposition that they are vertical, because the ratio
of weights is unaltered in turning from a vertical to an inclined position, but each
separate crank must be turned in the same direction as its own cylinder.
Balancing on this system applies to engines with four or more cylinders acting on
separate cranks of the same crank shaft and as an example let Figure 3 represent
a triple expansion engine with two equal low pressure cylinders as it might be
constructed to effect a balance of the reciprocating parts according to the method
described in the before-mentioned Specification; 1 is the high pressure cylinder,
II the intermediate pressure cylinder, and III and IV the two low pressure cylinders,
and OK, OK, OK, OK, (Figure 4) their respective cranks. The axes of
these cylinders are all in one vertical plane and in this particular case are equally
distant from one another and the cranks are as shown in Figure 4 OK, at 120°

page_text: to O K₁; and O K₁ at 90° to O̟ K and O K, at 90° to OK, and consequently OK₁
at 60° to O K. Let the weights of the reciprocating parts required in this engine
be P, P, P, and P, and in this case P₁ = P, and P₁ P₁.
=
If for practical reasons it is necessary to have the cylinders displaced from the
vertical in the manuer shewn in Figure 5, I and IV being at 15° to the right,
and II and III being at 15° to the left of the vertical plane through the crank
shaft, and at the same time preserve the vertical balance then I effect this in the
following manner.
Since the cylinder I is turned to the right through an angle of 15° I also turn
the crank OK, to the right through 15° to the position OK, Figure 6. In a
similar way the crank OK is turned through 15° to the position OK. Also
OK, and O K, are each turned to the left through 15° into the positions OK
and OK respectively. Since each cylinder has been turned through the same
angle it is unnecessary to make any alteration in the weights of the reciprocating
parts. The final positions of the cranks in this case therefore are such that they
are in planes at right angles (see Figure 7).
The angles between the cranks are thus fixed by the reciprocating weights. The
revolving weights on the cranks are not necessarily balanced at the same time.
These may be balanced in any one of several ways, for example
(1) The revolving weights on each crank may be balanced individually by a
counterweight exactly opposite it as in Figure 8.
(2) The revolving weights may be balanced as a system by adding a weight to
each of the end cranks. This is done as follows.
The final angle between the middle cranks OK O K↓ is now known to be 90°,
and the weights of the cranks O K and O K↓ are assumed to be known. The
weights of the cranks OK and OK will also be known. The balance
weight B, (Figure 9) in the same plane as O K] required to compensate for O K}}
and O K is shown by Schlick to be

page_text: If an amount, cos j₁ could be removed from the crank OK then we could
omit the component of ₁ opposite to the crank. If it is impracticable to remove
any weight from the crank itself, then, as far as approximate balance is concerned,
it may be removed from the reciprocating parts attached to the crank OK. The
only balance weight necessary in the plane of is then one equal to the component
of at right angles to the crank O K}.
Similarly a balance weight can be found placed at right angles to the
crank O KĄ.
The distances between the cranks are determined by the same considerations as
those applicable to cylinders in the same plane and discussed by Mr. Schlick in his
Specification aforesaid.
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 :-
In a multiple cylinder engine with four or more cylinders the axes of which are
not all in the same plane, the arrangement of the weights of the moving parts, and
the distances between, and the angles and lengths of, the cranks as, and for the
purposes, herein described.
Dated this 16th day of November 1895
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.