Improvements in Counterbalance and Guide for Reciprocating *Mechanism.
Year: 1893

page_text: Date of Application,, 10th Jan, 1893-Accepted, 4th: Mar., 1893
COMPLETE SPECIFICATION.
Improvements in Counterbalance and Guide for Reciprocating
*Mechanism.
1, MATTHIAS NACE FORNEY, Mechanical Engineer, residing at No. 501 Fifth
Avenue, in the City of New York, County of New York, State of New York, and
United States of America, ido 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 :--
::
My invention is m more particularly designed for application in, although not
limited to, simple and compound engines, and its object is to enable the momentum
of reciprocating parts. to be counterbalanced without inducing a disturbing action
at right angles to the movement of such parts, as well as to ensure the rectilineal
movement of the reciprocating parts without the employment of the ordinary
cross-head and guides. To this end; my invention, generally stated, consists in the
combination, with a reciprocating element, of a system of oscillating levers, and B
counterbalance connected ito said. levers and moving in a reverse direction to the
movement of the reciprocating element. The improvement claimed is hereinafter
fully set forth.
The reciprocating parts of engines have heretofore been and are now usually
counterbalanced by the..attachment.of counterweights to the main shaft of the
engine opposite to the crank or cranks. Such attachment serves to counteract
the momentum of the piston and connected parts in their rectilineal: movement,
but as the counterweight necessarily traverses a circular path, it induces a
disturbing: action on the shaft at right angles to the direction of movement of the
piston. This disturbance is, in all cases, objectionable, and is found in locomotive
engines to be a serious disadvantage, it being said.to be sometimes sufficient,at
high speeds, to bend the rails below the wheels and impose dangerous strains on
bridges and other structures of the permanent way. My invention is designed. to
substantially eliminate this disturbing action by means of a construction which.at
the same time.dispenses with the ordinary guiding devices, and which, in.a form
adapted for practical application, will now be described.
In the accompanying.drawings:
Figure 1 is a vertical longitudinal central section through the cylinder of a steam
engine in which my invention is applied;
Fig. 2, an end view.as seen from the left of Fig. 1 ;
Fig. 3, a horizontal central section; Fig. 4, a vertical longitudinal central
section through the cylinders of a steam engine of the compound type, illustrating
another form of application of my invention;
Fig. 5, an end view, as seen from the left of Fig. 4, and ;
Fig. 6, a horizontal central section, on the line x, x, of Fig. 4.
Referring to Figs. 1, 2 and 3, the cylinder 1, which is of the ordinary construc-
tion, is fitted with a piston 2, secured upon a piston rod 3, the outer end of which
is coupled to a connecting-rod 4, through which power is transmitted to a crank-pin
for the rotation of a shaft. In lieu of being secured to a cross-head, fitted to slide
in guides, as in common practice, the outer end of the piston is coupled, preferably,
as shown, by the connecting-rod pin 5, to a system of oscillating levers 7, 8, forming
what is known as a
"parallel motion," by means of which the outer end of the
piston-rod is caused to move in a straight line, thereby dispensing with the cross-
head and guides ordinarily employed for this purpose.
The two levers, 7, which are coupled at their lower ends, one on each side, to
the piston-rod 3, and which may be termed primary levers, are pivotally connected
at their upper ends, as by a pin 9, to a sliding block 10, which is fitted to work on

page_text: i
or between a fixed guide or guides 11, and are intermediately coupled, by a pin 12,
to the upper ends of a pair of secondary levers 8, which are arranged on the
outside of the primary levers 7, in order to ensure greater stability and to permit
the primary levers to work freely between them, and are provided with journals. 13,
which are mounted in fixed bearings 14, forming fulcra about which the secondary
levers 8 are adapted to oscillate as indicated by the dotted lines a, b, and c, d,
Fig.
In operation, assuming the piston and piston-rod to be in the position shown in
Fig. 1, and to be moved towards the right,, as indicated by the arrow, the lower
ends.of.the primary levers 7 will also move to the right, and the coupling pin 12,
by which their middle portions are connected to the upper ends of the secondary
levers 8, will move in the are a b, described in the oscillation of the secondary levers
about the axial line of their journals 13. The upper ends of the primary levers,
however, being coupled to the sliding block 10, which is only free to move in a
vertical rectilineal path, are constrained to move in the same path as. said sliding
block. The primary levers 7, therefore, oscillate. about the axis of the coupling-
pin 12, and their lower ends tend to describe an arc from said axis, curved in the
'opposite direction to the arc described by the upper ends of the secondary levers 8.
The arms of the primary levers on opposite sides of the coupling pin 12 are equal
in length, and equal to the distance between the axis of said pin and the axis of
the journals 13 of the secondary levers, and it therefore results from the conjoined
action: of the primary and secondary levers, that the lower ends of the primary
levers, and the connected outer end of the piston rod, are compelled to move in a
right line. So far as above described, this construction, which dispenses with the
ordinary cross-head and guides, is in substantial accordance with a known form of
parallel motion, and is not therefore, in and of itself, claimed as new.
My present invention utilizes the known function of the above construction, and
.combines therewith that of counterbalancing the reciprocating parts, by forming
arms on the secondary levers extending from their journals in opposite direction to
those to which the primary levers are coupled, and connecting to said opposite
arms a counterbalance which moves therewith in opposite direction to the piston
and piston rod and thus balances or counteracts their momentum. As shown in
Figs. 1 to 3, the counterbalance is a dead weight 15, which is secured to the
lower arms of: the secondary levers by bolts 16, but such specific form is not, as
will hereinafter be shown, of the essence of my invention.
..It will be observed that the path of the centre of gravity of the weight 15 is
in an arc of a circle and not, as would be more desirable, in a right line as in the
case of the piston and rod. The disturbance due to the difference in the direction
of motion of the counterbalance and of the piston respectively is, however, very
slight, and is represented by the versed sine of the arc described by the centre of
gravity of the counterbalance, whereas that of a revolving counterbalance, set
oppositely to the crank as in ordinary practice, would be represented by the
diameter of the circle described by its centre of gravity. The construction above
described induces much less disturbance at right angles to the piston, and at the
same time counteracts the momentum of the piston and connected reciprocating
parts. The elimination of the cross-head and guides is a further feature of
advantage, these being expensive to construct and maintain particularly on.
locomotive engines, where they are exposed to grit and dust and their proper
lubrication is difficult.
Figs. 4, 5, and 6 illustrate another form in which the essential features of my
invention as before described are embodied, in an application thereof to a
compound steam engine. The construction and relation of the low. pressure
cylinder 1, its piston 2, piston rod 3, and the primary and secondary levers 7, 8,
are as before described, but in lieu of employing a dead weight 15 as a counter-
balance, as in the former instance, the lower arms of the secondary levers 8 are
coupled to the piston rod 3" of the high pressure piston 2", which reciprocates in
the high pressure cylinder 1ª, said high pressure piston and rod performing the same

page_text: function, in combination with the system of oscillating levers and the low pressure
reciprocating members, as is performed by the counterweight 15, and acting as the
mechanical equivalent thereof. The secondary levers 8 are coupled to the high
pressure piston rod by a pair of links 17, and said piston rod is secured to a cross-
head 18, sliding on a guide 19, for the reason that the parallel motion function of
the primary and secondary levers is operative only upon the low pressure piston-
rod and piston.
While I have herein described and shown my invention as applied in counter-
balancing and guiding reciprocating parts of steam engines, for which special
function it is desirably applicable, I do not limit myself to such specific application,
as it will be obvious that it is likewise applicable, without variation of principle
or substantial modification of structure, in connection with the reciprocating
elements of other mechanisms. Neither do I desire to confine myself to the
specific arrangement of oscillating levers described and shown, for the reason that.
a counterbalance adapted to move in opposite direction to a reciprocating member,
and connected to some other form of linked or articulated parallel motion
mechanism, would, in combination therewith, present all the essential features of,.
and operate similarly to and with the same result as, the specific constructions
herein in detail described and shown.
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. The combination, with a reciprocating element of mechanism, of an articulated
system of oscillating levers or links, connected to the reciprocating element and.
forming a guide to ensure rectilineal motion thereof, a guiding member for said
system of levers, and a counterbalance connected to said system of levers and
moving in opposite direction to the reciprocating element, substantially as.
set forth.
2. The combination, with a reciprocating element of mechanism, of a primary
oscillating lever coupled at one end to the reciprocating element and having a
movable fulcrum at its opposite end, a double armed secondary lever, oscillating
in fixed bearings and having one of its arms pivotally connected to the primary
lever at the middle thereof, and a counterbalance connected to the opposite arm of
the secondary lever, substantially as set forth.
3. The combination, with a reciprocating element of mechanism, of a primary
oscillating lever coupled at one end to the reciprocating element and having a.
movable fulcrum at its opposite end, a double armed secondary lever, oscillating in
fixed bearings and having one of its arms pivotally connected to the primary lever
at the middle thereof, and a dead weight connected to the opposite arm of the
secondary lever, substantially as set forth.
4. The combination, with a reciprocating piston and piston rod, of a primary
lever coupled at one end to the piston rod and at the other to a sliding block, a
fixed guide on which said block is fitted to move rectilineally, a double armed
secondary lever journalled in fixed bearings and having one of its arms pivotally
connected to the primary lever at the middle thereof, and a counterbalance
connected to the opposite arm of the secondary lever, substantially as set forth.
Dated at New York. N.Y ILSA this Sixteenth day of December
Witnesses:
FRANK J. FRENCH,
FREDERICK HOBART.
MATTHIAS NACE FORNEY.