IMPROVEMENTS IN THE CON- STRUCTION OF ATMOSPHERIC PRESSURE ENGINES OR MECHANISM
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Henry Gardner at the Office of the
Commissioners of Patents on the 4th July 1877. (A communication from
abroad by James Dobbie, of St. Petersburg, in the Empire of Russia, British
Subject.)
HENRY GARDNER, of the Firm of Robertson, Brooman, and Company, of 166,
Fleet Street, in the City of London, Patent Agents. "IMPROVEMENTS IN THE CON-
STRUCTION OF ATMOSPHERIC PRESSURE ENGINES OR MECHANISM." (A communication
from abroad by James Dobbie, of St. Petersburg, in the Empire of Russia, British
Subject.)
This Invention consists principally and generally in new or improved modes of
obtaining or producing motive power from or by the ordinary pressure of the
atmosphere, all of which improvements constituting this said Invention will render
motive-power engines or mechanism constructed in accordance therewith more
simple in their construction and action, and be produced and maintained thereafter
in action more economically, relatively, and generally, than they have been hereto-
fore constructed.
The motive power generated or produced in the cylinders of my new or improved
engines or mechanism being derived from the ordinary pressure of the atmosphere,
naturally involves the necessity of creating and maintaining a vacuum in the
cylinders, and neutralizing its action or effect in reciprocal succession at every stroke
of the piston. This two-fold object is effectually accomplished by the conjoint
action of an arrangement of levers and modification of "parallel motion" mechani-
cally true and well adapted, not only to supply the practical means of obtaining that
amount of mechanical power which the properties of the atmosphere confer upon a
vacuum, but to neutralize its action.
This engine has two horizontal cylinders immovably fixed to a sole plate; each
cylinder is open at one end, and is provided with two pistons with their respective
piston rods; one of the piston moves through that part of the cylinder of least
diameter, and the other through that part of the cylinder of greatest diameter, in
which the vacuum is created, and the cubical capacity of the latter is equal to the
cubical capacity of the former. One of the piston rods works through a stuffing
box on the cylinder cover of requisite length, and properly packed in order to
prevent the admission of air into the cylinder between the cylinder cover and the
177

page_text: piston, the difficulty however in general of preventing this is absolutely overcome
by the expedient here devised of forming a reservoir between the bottom of the
stuffing box and the cylinder cover, through which the piston rod works, or by means
of two stuffing boxes with a reservoir between them, and keeping it always filled
with oil or other unguent; this coluinn or reservoir of oil or other unguent not
only positively prevents the admission of air into the cylinder, but serves to lubricate
the piston rod.
The face of the cross head at the extremity of the piston rod of the piston is
rectangular; it is grooved and planed, and serves the purpose of a guide for the
slide of the lever (there being a lever to each cylinder); this slide is not only planed
on the face, but also on the lateral edges, which are angular, to fit the groove in the
rectangular face of the cross head, to enable it to traverse in it with uniform motion
without shake or play.
The slide on the lever is in constant contact with the cross head attached to the
end of the piston rod of its piston, and the modification of the "parallel motion,"
such as to effect a translation motion of the lever equal to the length of the stroke
of the piston, and the weight applied to the end of the lever (the action of the
lever on the piston however taken into consideration) sufficient, not only to over-
come the pressure of the atmosphere and the friction, but to make it preponderate.
The weight or load applied to the end of the lever may be substituted by a spring
balance.
Now supposing the piston to be at the termination of the stroke which brings it
into immediate contact with the under side of the cylinder cover, the preponderant
action of the weighted or loaded lever will cause the piston to move through the
cylinder the determined length of its stroke, and a vacuum will inevitably be formed
between it and the cylinder cover.
To create a vacuum in the cylinder when the piston is in close contact with the
cylinder cover, and the piston at that part of its stroke corresponding to the
position of the crank, it is only necessary to open the valve and keep it open till
the action of the loaded lever forces the piston to that part of its stroke corre-
sponding to that of the piston, when it is instantly closed.
The object of the valve is to allow the requisite volume of air from between the
two pistons to escape, which would otherwise become compressed when the piston is
subjected to the action of the loaded lever.
The force imparted to the piston from the pressure of the atmosphere by the open
end of the cylinder is communicated to the main shaft by any of the ordinary
means, such as connecting rods and cranks, whereby the rectilinear motion of the
piston is changed into a circular motion, or it may be transmitted direct for purposes
requiring only reciprocatory motion.
The means employed to effect the rise and fall of the loaded lever at every
reciprocation of the piston consists in the application of a loaded lever in reversed
order to that of the other lever worked by an eccentric or cam forged or keyed on
the main shaft, and revolving with it (there is a lever and eccentric or cam to each
cylinder), one end of the lever is in constant contact with the eccentric or cam, and
the other end in constant contact with the channelled cross head of the upright or
vertical rod, and the modification of the "parallel motion," such as will enable the
lever and the upright or vertical rod to perform a motion of ascent and descent equal
to the throw of the excentric or cam.
The weight applied to the end of the lever is sufficient not only to act as a
counterbalance to counterpoise the loaded lever, but to overcome the friction of the
moving parts and preponderate; the gravitation of this preponderance depresses
the vertical rod, the lower end of which, resting on the circular disc of the small
beam or lever, causes it to vibrate on its centre, and raise by means of the other
vertical rod the loaded lever (there are two vertical rods to each cylinder and two
levers).
The chord of the are described by the angular motion of the lever is equal

page_text: to the determined distance which the rod and the two levers require to rise and
fall.
The weight or load applied to the end of the lever may be substituted by a spring
balance.
The cylinder, open at one end, placed between the two cylinders, suits the purpose
of equalizing the motion of the engine by forcing the piston through the cylinder
against the pressure of the atmosphere by the intermediate mechanisin of the crank
and the connecting rod, whereby a vacuum is formed in the cylinder between the
piston and the cylinder cover, the piston is consequently forced back through the
cylinder by the pressure of the atmosphere, and thus the surplus force absorbed at
one part of the action of the engine is again distributed when the action is deficient.
The application of this expedient for equalizing the motion, will however be more
available where my new or improved atmospheric pressure engines are applied to
the purposes of locomotion, than to stationary engines where it may be substituted
by the fly wheel.
My atmospheric pressure engines may be constructed with one, two, or more
cylinders, and the position of the cylinders may be either horizontal, vertical, or
oblique, or partly horizontal and vertical, or partly horizontal and oblique, and each
cylinder may be either of equal or unequal diameter; the purpose for which the
engine is to be employed will however determine the situation or position of the
cylinders, and whether they are to be of equal or unequal diameter.
When the cylinders employed are of equal diameter throughout, one piston in each
cylinder may be adapted; and when the cylinders have each two pistons, the space
between them may be filled with oil or other unguent.
Although mention is made of the use of the ordinary metallic or hemp packed
piston in the cylinders of these atmospheric pressure engines, it is prefered to use a
piston consisting of a solid or hollow cylinder or barrel (having projecting edges or
flanges) surmounted by a solid ring of elastic material. free to slide or slip on the
cylinder or barrel between the projecting edges or flanges in the direction of its
length, or to use a plunger piston consisting of a sack or bag of impermeable
material attached to the piston rod, and which when unfolded or extended, will,
in one direction of the stroke, take the place of the air, which it will drive before
it, and in the opposite direction will fold or collapse and create a vacuum in the
cylinder.
The piston in the cylinders may be substituted by either of the two latter kinds of
piston just described.
The cylinder covers are all provided with cocks or valves in order that
any air
which may in the course of time gain admission into the vacuum between the piston
and the cylinder cover may be ejected by opening the cocks or valves and raising
the lever.