Improvements in Direct Acting Steam or Pneumatic Engines.
Year: 1888

page_text: Improvements in Direct Acting Steam or Pneumatic Engines.
I, GUSTAV A. BARTH, of 417 Olive Street in the City of St. Louis, State of
Missouri, United States of America, 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 :-
My invention relates to improvements in that class of Direct acting steam, pneumatic
or other motive fluid engines in which the piston is reciprocated in the cylinder by
the action of its valve without the intervention of valve operating mechanism, and has
for its object to render such engines more positive and sensitive in action under high
and low pressures when used for chipping, calking, riveting, pumping and other
purposes.
My invention consists in the combination of a cylinder bored out concentrically to
two different diameters for different portions of its length, a tubular piston rod pro-
vided with an improved arrangement of inlet and discharge passages, a distribution
valve adapted to reciprocate within said piston rod, a regulating valve for controlling
the supply of the steam or air to the piston, and, in my adaptation of it to a chipping
machine, as will be hereinafter described (in which a hammer head is removeably
secured to said piston rod) a handle by which the machine is held to its work, in con-
junction with which is a lever and spring for operating the valve.
On the accompanying drawings Figuies 1 and 2 represent longitudinal central
sections of my improved direct acting engine adapted for use as a chipping machine,
the piston being shown at the upper and lower teriminations respectively of its stroke
and Figures 3 and 4 transverse sections on lines 1 1 and 22 respectively in figure 1 ;
like letters of reference denoting like parts in all the figures
a represents the cylinder which is bored out concentrically to two different diameters
extending respectively in opposite directions from a plane at or near the middle of its
length and corresponding with the diameters of its piston band of a tubular piston
rod c which is tormed in one piece with, or secured to the piston b. The piston b and

page_text: 9
piston rod care bored out centiilly to provide a cylindrical chamber or cavity d
which extends downwards from its upper open end, where it is flush with the upper
side of the piston, to a surtible depth within the piston rod cm the lower end of
which is inserted the hammer stock e carrying a hammer upon its outer end.
In the
upper open end of the chamber d is fitted and fixed a cylindrical tube or sleeve a w which
is flush at its top with the upper side of the piston band extends a certain distance
downwards within the chamber d Into the lower portion of this tube or sleeve o pro-
jects the upper diametrically reduced end portion of a cylindrical distribution valve h
wh ch, to the extent of that portion of its length below the shoulder of its reduced end,
is fitted to, and capable of vertical reciprocation within the chamber d and is formed
with a vertical central supply passage extending from its upper open end within the
tube or sleeve to a suitable depth therefrom--an inlet passage being formed near
the lower end of the supply passage through the wall of the distribution valve / and
communicating with an annulai space formed by a circumferential recess, on the
valve in conjunction with the interior surface of the chamber d IP are inlet
passages leading to the chamber d through the wall of the latter from the outside of
the tubular piston rod c, and communicating with each other by an open groove ¹ formed
in the outer surface of the piston rod c m is an inlet and outlet passage located on the
outside of the piston rode below the inlet passage and extending through the wall
of the piston rod c and through the bottom of the chamber d with which it com-
municates beneath the distribution valve h, and n is an exhaust passage extending
from the interior of the tube or sleeve though the wall of the latter and downwards
through a portion of the piston b, and through the wall of the piston 1od c to the space
between the lower end of the latter and the corresponding end of the cylinder a from
which space, exhaust passages n¹n extend through the lower end of the cylinder a
and open into the external atmosphere
Steam or other motive fluid is admitted to the machine through a flexible hose or
other pipe attached to the nozzle o which communicates with a passage p opening
into the cylinder a beneath the piston b the flow of steam being regulated
according to the quantity required, by a plug (or other) regulating valve q
which is fitted and works in a casing formed diametrically through the base
or flanger of the handles by which the machine is manipulated when being used
as a chipper the flange being secured by screws or otherwise to the head
of the cylinder a and constituting the cover thereof On one end of the plug or
spindle of the valve g is fixed a specially shaped levert between which and the
handle s is a spring u attached at one end to the handle s and at its other end to
the levert so that when holding the handles the lever being moved by one of the
fingers in one direction against the spring u will partially rotate or move the valve
so as to open and admit steam or air to the passage p and on releasing the finger the
reaction of the spring u will return the lever t and rotate the valve q to a corresponding
extent in the opposite direction thereby closing the valve q.
9.
Through a central square hole in the lower end of the cylinder a is inserted the
shank of a chisel w, the upper end of the shank » projecting somewhat into the
cylinder a and its shoulder bearing against the outer end thereof
The
In operation, the parts being in the position seen in figure 1 the operator holds the
machine in the desired position for the work by one hand around the lower end
portion of the cylinder a and the other on the bandles, using one finger to control
the lever t, which moves the regulating valve q for admitting more or less steam or
air to, and shutting it off from, the passage p and cylinder a as required
motive fluid entering the cylinder a between it and the piston rod c as indicated by
the arrows circulates beneath the piston around the piston rod c so as to pass through
the inlet passage and around the annular space into and through the inlet
passage and central supply passage of the distribution valve h, through the tube
or sleeve g to above the piston b, which with the piston rode and hammer is thereby
forced downwards in the cylinder a until the hammer strikes the shank of the
chisel was seen in figure 2 In the meanwhile the outlet passage m on passing the
lower end of the small portion of the cylinder a corresponding with the diameter of

page_text: the piston rod c and the inlet passages entering the same part of the cylinder a
and being thereby closed to the ingress of steam from the passage p, the steam which
was below and supported the distribution valve in its raised position is exhausted
through the passage m and allows the distribution valve to drop to the bottom of the
chamber d so as to close the inlet passages 12 and thereby prevent the subsequent
entrance of live steam from the passage p to the central supply passage during the
upward stroke of the piston b
Simultaneously, by the dropping of the distribution valve its upper reduced end
portion uncovers the exhaust passage n, through which, and through the exhaust
passage n n the steam from above the piston bis exhausted into the atmosphere, and
the steam from the passage p occupying the space beneath the piston between the
cylinder a and piston rod c presses upon the lower annular surface of the piston b
and thereby raises the latter with the rod c and hammer until the inlet passage m
rises just above the upper end of the said small portion of the cylinder a when the
steam from the passage p enters the passage m and chamber d and lifts the distribution
valve h to its original position, or with the shoulder of its reduced end bearing against
the lower end of the tube or sleeve g, as seen in figure 1, so as to again open com-
munication between the inlet passages 3, 4 and 1 for admitting the steam or air to above
the piston ; and between the passages and admitting steam beneath the dis-
tribution valve h for supporting the latter in the raised position during the downward
stroke of the piston b.
To prevent accidental rising of the distribution valve h in the chamber d during the
upward stroke of the piston b a slight downward or back pressure is imparted to the
valve by a small inlet passage a which is located at or near to the underside of
the piston and opens from the outside, and through the wall of, the piston rod c into
the chamber d above the valve h between the shoulder of its reduced end and the
lower edge of the tube or sleeve g when the valve his in its lowest position.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is
1 The combination of a cylinder, a piston fitting therein, a tubular piston rod
formed on or secured to said piston and provided with separate inlet and exhaust
passage, a distribution valve fitting within a chamber or cavity in said piston rod and
having a central supply passage extending from its open end to a lateral port and
annular passage adjacent to its opposite closed end, the port and passages being so
arranged as to communicate alternately with the said inlet and exhaust passage of the
piston rod, an inlet passage in the piston rod communicating with that portion of the
chamber therein beneath the distribution valve and communicating by a connecting
inlet passage with the inlet passage through the piston rod to the port and central
supply passage of the distribution valve, and a combined inlet and exhaust passage in
the piston rod leading to and from the bottom of the chamber therein beneath the
distribution valve, the whole operating to hold and reverse the distribution valve at
the proper times and so to govern the supply and exhaust of motive fluid to and from
the piston and distribution valve, substantially as set forth
2. The combination of a cylinder, a piston fitting therein, a tubular piston rod
formed on, or secured to, said piston and provided with a separate inlet and
exhaust passage, a distribution valve fitting within a chamber or cavity in said piston
rod and having a central supply passage extending from its open end to a lateral port
and annular passage adjacent to its opposite closed end, the port and passages being
so arranged as to communicate alternately with the said inlet and exhaust passage of
the piston rod, an inlet passage in the piston rod communicating with that part of the
chamber therein beneath the distribution valve and communicating by a connecting
inlet passage with the inlet passage through the piston rod to the port and central
supply passage of the distribution valve, a combined inlet and exhaust passage in the
piston rod leading to and from the bottom of the chamber therein beneath the dis-
tribution valve, and an inlet passage in the piston rod communicating with the

page_text: chamber therein above the upper shoulder of the distribution valve when in its lowest
position within the said chamber, the whole operating to positively hold and reverse
the distribution valve at the proper times and so to govern the supply and exhaust of
motive fluid to and from the piston and distribution valve. substantially as set forth.
3 The combination with a cylinder, a piston and rod working therein, a distribution
valve, and a regulating or controlling valve for governing the supply of steam or other
motive fluid to the distribution valve, of a lever connected with the regulating or con-
trolling valve and coupled by a spring with the handle used for directing and holding
the machine to its work, substantially as and for the purpose described.
Dated this 28th day of April 1888.
PAUL
BAKEWELL,
Agent for Gustav A. Barth.