IMPROVEMENTS IN TRANSMITTING MOTION IN AND IN COUNTERBALANCING THE MOVING PARTS OF ENGINES
Year: 1878

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN TRANSMITTING MOTION IN AND IN COUNTERBALANCING THE MOVING PARTS
OF ENGINES." A communication from abroad by Joseph Marie Hector Eugène
Vicaire, of Paris, France.
Sealed the 22nd October 1878, and dated the 30th April 1878.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 30th April 1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN TRANSMITTING MOTION IN AND IN COUNTER-
BALANCING THE MOVING PARTS OF ENGINES." [A communication from abroad by
Joseph Marie Hector Eugène Vicaire, of Paris, France.]
This Invention relates to the transmission of movement in engines generally, and
to improved means of neutralising the effects of the inertia of the moving parts,
According to this Invention I retain the use of revolving counterweights as
before used for this purpose, but only for the purpose of balancing parts having
rotary motion, and I balance the other parts of the engine by means of a counter-
weight having reciprocating motion, and which receives its motion direct from the
piston or other part in connection therewith (and not through the axle or driving
shaft of the engine) through the agency of a lever or similar arrangement which
transmits motion in the inverse direction.
The most suitable form of apparatus, and in certain cases the only one capable of
being used for effecting this transmission of motion, consists of a sort of lever or
jointed beam composed of six rods, two of which cross one another at the pivot or
centre of the oscillatory motion, and whose length is such as to form on either side
of this pivot quadrilaterals similar to each other and similarly placed, that is to say,
homothetic relatively to this point.

page_text: It will be readily seen that the diagonals of these two quadrilaterals are always
prolongations the one of the other, and that the ratio of their lengths, when these
quadrilaterals are changed in form, remains always equal to those of the homologous
Bides.
Figure 1 of the accompanying Drawing is a diagram showing the arrangement of
this beam, and also how, to the two principal quadrilaterals AOCF, OBED, may
be added other quadrilaterals, homothetical to the first relative to their common
apices, such as the quadrilateral E¹ B' D'O', whose sides E B', E D¹, are prolongations
of EB and ED. Whatever may be the number of these quadrilaterals their
diagonals will be always in the same straight lines, and the apices on this diagonal
will describe homothetical lines inverse in the case of those points situated on
opposite sides of the pivot, and direct in the case of those situated on the same side.
In case of the latter the motion will be parallel and in a constant ratio as regards
its extent; but directed in the same direction it may in certain cases be advan-
tageous to use levers thus formed of several consecutive quadrilaterals.
The rods may also be in pairs of equal length, so as to form a symmetrical figure,
as shown in Figure 2. In this case the point of attachment of the beam is at the
joint of the connecting rod with the piston rod, but it might be connected to the
rod at any other point.
In many cases it will be found advantageous to still further simplify the ratios of
the lengths of the various rods, so that tho quadrilaterals form lozenge-shaped
figures, see Figure 3, which shows a counterweight moved by a beam formed of two
lozenge-shaped figures. In this Figure the point of attachment is on the connecting
rod itself instead of on the piston rod.
The slight movement of the counterweight in the vertical direction causes a
re-action also in a vertical direction, which enables the vertical re-actions produced
by the inertia of the piston rod to be balanced. Calculation shows that in this case
by a suitable selection of the point of connection of the beam, and provided that.
the pivot be placed in the line of the geometrical axis of the engine cylinder, the
effects of inertia may be practically neutralized.
Instead of a single counterweight having its pivot, on the axis of the eylinder
two counterweights may be employed symmetrically placed relatively to this axis.
The jointed beam above described may be employed to move not only counter-
weights but other parts of engines. Its application for the transmission of motion
in engines generally constitutes another feature of the Invention.
As an example I will describe the use of an articulated or jointed beam in lieu of
the rigid beam of a beam engine.
Figure 4 is a diagram showing the arrangement which may be adopted for this
purpose. The beam is supposed to form two symmetrical and equal quadrilateral
figures; but they might be unequal if the strokes of the two pistons are unequal
in length. It is only necessary that one extremity should be guided in a straight
line, the other necessarily moving in a straight line owing to the construction of the
beam, whereas in the ordinary beam engine a parallel motion is necessary at each
extremity. This guiding may be effected by means of slides or otherwise. Figure 4
shows how this may also be effected by means of three rods, one jointed at point H.
These three rods AG, G C, and GH, shown in dotted lines, jointed to the symmet-
rical quadrilateral O AFG, constitute a Peaucellier parallel motion which compels
the apex F to nove in a straight line perpendicular to OH. The combination of
the Peaucellier motion with this jointed beam is an essential feature of the
Invention.
The advantages of this jointed beam over the ordinary beam will be readily
understood. By whatever means the end F may be guided this jointed beam may
oscillate through longer arcs than the ordinary beam, which is limited in its motion
by the working of the Watt parallel motion; therefore, for a certain length of
stroke the length and strength of the beam and the space it occupies may
considerably reduced. As the strain is divided between the double beam ABCD
instead of a single beam as usual, cach of the former may be of one-half the
be

page_text: strength for the same length of beam. It will be remarked that the jointed beam
with the Peaucellier parallel motion consists of nine rods, the same number as a
rigid beam with a Watt's parallel motion at each end, and that the number of joints
are fewer.
Another advantage of the jointed beam is that it will enable the two cylinders of
a blowing engine or pump to be juxtaposed.
The combination of the jointed beam of this Invention with the Peaucellier
parallel motion may be applied in other cases, for example, in Figure 2, which
represents a direct-acting engine furnished with a counterweighted beam of this
Invention, are shown in dotted lines, the rods to be added for obtaining a paralle!
motion without the use of guides.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
29th October 1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN TRANSMITTING MOTION IN AND IN COUNTER-
BALANCING THE MOVING PARTS OF ENGINES." A communication from abroad by
Joseph Marie Hector Eugéne Vicaire, of Paris, France.
This Invention relates to the transmission of movement in engines generally, and
to means of neutralising or avoiding more completely than has been possible hitherto
the effects of the inertia of the moving parts which it is well known produces
movements or tendencies to movements of the engine relatively to surrounding
objects.
It is in regard to locomotive engines more particularly that attention has been
given to these various pitching, rocking, oscillating, swivelling, and tail motions of
the engine, and it has been sought to avoid them by means of balance weights fixed
on the wheels, but with only partial success. These balance weights having circular
motion may avoid the effects of inertia of parts receiving similar motion, such as
cranks, coupling rods, and to a certain extent the connecting rods. But by the very
nature of their notion these balance weights cause re-actions in directions constantly
varying according to the position of the balance weight in the circle which it
describes. If this circle is in a vertical plane, as in the case of a wheel, the re-action
is at one time vertical, at another borizontal, and at another oblique. These
re-actions cannot therefore exactly equilibrate those produced by the parts receiving
alternate rectilinear motion, such as the piston and its rod, and to a certain extent
the connecting rod, these re-actions varying at each instant in amount but not in
direction; for instance, if this movement be horizontal, as is usually the case in
locomotives, and if the rotating balance weights be so regulated that their horizontal"
components shall completely equilibrate the re-actions of the piston and its adjuncts*
there will at same time be produced by the force of circumstances vertical com- .

page_text: ponents which nothing will destroy, and which will cause to re-appear in another
place or direction the very evil it was sought to avoid.
In a general way these rotating balance weights can only equilibrate, as regards
inertia, parts receiving similar motion. Heaton proposed to equilibrate locomotive
engines by means of parts exactly like and opposite to the parts of the engine itself,
viz., a false crank and connecting rod communicating alternate motion to a suitable
weight. This system, which was not even free from theoretical objections, has
never come into practical use, as it rendered the construction of the engine too
complicated.
According to this Invention I propose to retain the use of revolving counter-
weights, but only for the purpose of balancing parts having rotary motion, and I
balance the other. parts of the engine by means of a counterweight receiving
reciprocating motion direct from the piston or other part in connection therewith
(and not through the axle or driving shaft of the engine) through the agency of a
lever or similar arrangement, which, by oscillating about a fixed point or centre,
transmits the motion of the piston in the inverse direction.
I claim the application of this, the first part of the Invention, not only to Joco-
motives but to engines and machinery in general, and particularly to tramway
engines, portable engines, and the different engines used on steamships for propelling
and for auxiliary purposes.
The second part of the Invention consists in the special arrangement of apparatus
which is the most suitable and in certain cases the only one capable of being used
for effecting this transmission of motion. It consists of a sort of jointed lever or
beam constructed of six rods, two of which cross one another at the pivot or centre
on which the beam oscillates, and whose lengths are such as to form on either side
of this pivot quadrilaterals similar to each other and similarly placed, that is to say,
homothetic relatively to this point.
It will be readily seen that the diagonals of these two quadrilaterals are always
prolongations the one of the other, and that the ratio of their lengths, when these
quadrilaterals are changed in form, remains always equal to those of the homologous
sides. Consequently, if one of the vertices be arranged to describe a certain line
the opposite vertex will describe a homothetical line with a velocity and acceleration
always parallel and inverse in direction to the velocity and acceleration of the first
point, and in a constant ratio of amount therewith. If the first of these vertices be
connected to the piston of an engine, and generally to any body in motion, the other
vertex will have exactly the movement which should be given to a counterweight
in order to destroy the effects of the inertia of the piston or body, and this whatever
may be the position of the pivot in space.
Instead of two opposite vertices any two points may be taken situated at a given
moment on a straight line passing through the fixed point.
Figure 1 of the accompanying Drawing is a theoretic diagram showing the
arrangement of this beam, and also how, to the two principal quadrilaterals AOCF,
OBED, may be added others homothetical of the first relatively to their common
vertices, such as the quadrilaterals E¹ B¹ D¹ 0¹, whose sides EB', ED', are prolonga-
tions of EB and ED. Whatever may be the number of these quadrilaterals thus
placed, the one after the other, their diagonals will always be in the same straight
lines, and the vertices on this diagonal will describe homothetical lines inverse for
the points situated on opposite sides of the pivot, and direct for the points situated
on the same side. In the case of the latter the velocities will still be parallel and
in constant ratios, but directed in the same direction. It may in certain cases be
advantageous to use levers thus formed of several consecutive quadrilaterals.
The rods may also be in pairs of equal length, so as to form a symmetrical figure,
as shown in Figure 2. In this case the point of attachment of the beam is at the
joint of the connecting rod with the piston rod, but it might be connected to the
piston rod at any other point.
In many cases it will be found advantageous to still further simplify the ratios of
the lengths of the various rods, so that the quadrilaterals form lozenge-shaped

page_text: figures, see Figure 3, which shows a counterweight moved by a beam forming two
equal lozenge-shaped figures. In this ease advantage has been taken of the fact
that transmission by means of the jointed beam is applicable to curvilinear move-
ments to make the point of attachment on the connecting rod itself instead of on
the piston rod.
The slight movement of the counterweight in the vertical direction causes a
re-action also in a vertical direction which enables the vertical re-actions produced
by the inertia of the piston rod to be equilibrated. Calculation shows that in this
case by a suitable selection of the point of connection of the beam, and provided
that the pivot be placed in the line of the geometrical axis of the steam cylinder,
one is enabled to practically neutralise the effects or re-actions caused by inertia,
which tend to cause a pitching motion of the engine, so that the movements resulting
from inertia are destroyed in every direction.
Instead of a single counterweight having its pivot on the axis of the cylinder
two counterweights may be employed symmetrically placed relatively to this axis.
The jointed beam above described may be employed to move not only counter-
weights but other parts of engines also. Its application for the transmission of
motion in engines or machines generally constitutes the third part of the Invention.
It will be readily understood how this application may be varied infinitely. As
an example I will describe the use of an articulated or jointed beam in lieu of the
rigid beam of a steam blowing or pumping engine.
Figure 4 is a diagram showing the arrangement which may be adopted for this
purpose. The beam is supposed to form two symmetrical and equal quadrilateral
figures; but they might be unequal if the strokes of the two pistons are unequal in
length. It is only necessary that one extremity should be guided in a straight line
as the other then necessarily moves in a straight line also owing to the construction
of the beam, whereas in the ordinary beam engine a parallel motion is necessary at
each extremity. This guiding may be effected by means of slides or otherwise.
Figure 4 shows how this may also be effected by means of three rods, one jointed
at point H. These three rods AG, GC, and G H, shown in dotted lines jointed to
the symmetrical quadrilateral OAFG, constitutes in fact a Peaucellier parallel
motion which, provided the rods be of proper length, compels the vertex F to move
in a straight line perpendicular to OH. I claim particularly this combination of
the Peaucellier motion with the jointed beam.
The advantages of this jointed beam over the ordinary beam will be readily
understood. Thus by whatever means the end F may be guided this jointed beam
may oscillate through longer arcs than the ordinary beam, which is limited in its
motion by the working of the Watt parallel motion; therefore for a certain length
of stroke the length and strength of the beam and the space it occupies may be
considerably reduced. As the strain is divided between the two parts A B, CD, of
a double beam, instead of being borne by a single beam as usual, each of the former
may be of one-half the strength for the same length of beam. The beam is thus
much more easily and cheaply constructed, and works better than the old beam. It
will be remarked that the jointed beam with the Peaucellier parallel motion consists
of nine rods, the same number as a rigid beam with a Watt's parallel motion at
each end, and that the number of joints are fewer.
Another advantage of the jointed beam is that it works equally well in a position
oblique to the arcs described by its two extremities, which will enable the two
cylinders of a steam blowing engine or pump to be juxtaposed.
The combination of the jointed beam of this Invention with the Peaucellier
parallel motion may be applied in other cases; for example, in Figure 2, which
represents a direct-acting engine furnished with a counterweighted beam of this
Invention, I have shown in dotted lines the rods to be added for obtaining a parallel
motion without the use of guides.
Having described the nature of the Invention, and the manner of performing the
same, I would have it understood that the annexed Drawings illustrate only a few
examples of the possible applications of the Invention, which may be variously

page_text: modified as found desirable; but what I claim as the Invention to be protected by
the herein-before in part recited Letters Patent is, the new system of counterweight
herein described, applicable to all kinds of engines or machines, and particularly to
locomotive engines, as well as the system of jointed homothetic beam, whether
employed to move counterweights or apparatus of any kind.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set my
hand and seal, this Twenty-ninth day of October, in the year of our Lord
One thousand eight hundred and seventy-eight.
NT i T
A. M. CLARA
(LS.)