CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1853

page_text: PROVISIONAL SPECIFICATION left by John Jonathan George
Collins at the Office of the Commissioners of Patents, with his
PROVISIONAL SPECIFICATION left by John Jonathan George
Collins at the Office of the Commissioners of Patents, with his
Petition, on the 14th September 1853.
(Void by reason of notice to proceed not having been given within the
time prescribed by the Act.)
I, JOHN JONATHAN GEORGE COLLINS, of Philadelphia, in the United
States of America, Engineer, do hereby declare the nature of the said
Invention for "CERTAIN IMPROVEMENTS IN STEAM ENGINES" to be as
follows, that is to say:
It consists, firstly, in an improved mode of effecting the cut off of the
steam entering the cylinder, so as to act expansively during a certain
portion of the stroke. Fig. 1, in the annexed sketch represents a
general view of the apparatus which I employ for this purpose. A, is
a cross section of the stud of a rocking shaft lever, by which an ordinary
slide valve is supposed to be actuated. This stud passes through a slot
in the link B, which is capable of being adjusted higher or lower upon
it by a screw, as shewn. C, is a common eccentric, keyed on to the
driving shaft of the engine, and working the link backwards and for-
wards in the usual manner. Attached to the eccentric block, and con-

page_text: centric with its outer ring, is a toothed wheel D, giving motion to a
pinion E, which runs in bearings prepared for it on the part connecting
the ring with the link B. The pinion has an eccentric or eccentric
stud upon it, connected with the link B, in such a manner that the
upper part of the latter obtains a vibrating motion additional to that
communicated by the ordinary eccentric. Thus, when the stud A, is
placed in a line with the lower eccentric pin, the valve will have the
usual motion due to the eccentric, but when it is raised higher in the
slot (or, in other words, when the link is depressed), a compound motion
will ensue, by means of which the steam port will be closed earlier than
otherwise, and the steam cut off at any point desired, according to the
amount of depression of the link. I usually place a wheel and pinion
on each side of the eccentric C, alternating the spaces and the teeth of
one pair with those of the other, so as to obtain smoothness of motion.
The link B, may be attached to the governor or regulator so as to vary
the expansion according to the speed of the engine; and in this case I
employ a counterweight to balance the weight of the link and rods, and
render the motion more delicate.
My Invention relates, secondly, to an improved throttle valve, and
the mode of connecting the same with the governor. A general view
of this is shewn in Fig. 2. A, is a double beat valve, fitted in a
suitable casing. The steam moving to the cylinder passes in the direc-
tion of the arrows so as to have a tendency to open the valve. B, is a
spring balance (for which also a counterweight may be substituted)
tending to close the valve by pressing on the lever b, the axis of which
passes through a stuffing box in the casing, and is furnished in the
interior with a small crank c, connected with the valve by a link. D,
is a rod working in guides, and attached to the governor so as to have
a back and forward motion according to the speed of the engine. It
has also upon it a small inclined plane d, which passes through a bridle
or strap e, on the under side of of the spring balance. The action is as
follows: When the piston is about to commence its stroke the steam,
by its pressure, opens the valve A, and fills the passages; it then imme-
diately closes the valve again by reaction, until the piston begins to
move; as the pressure then slackens off the valve again opens to supply

page_text: more steam, to an extent regulated by the difference of pressure on
each side of the valve and the tension of the spring B. As the speed
of the engine increases or diminishes, the action of the governor inserts
or withdraws the wedge . passing through the strap e, so as to increase
or diminish the strength of the spring, and give it more or less tendency
to resist the pressure of the entering steam.
Instead of a double beat valve a common conical valve may be used,
and in some cases the connection of the valve with the governor may
be dispensed with.