Year: 1888

page_text: I, ERNST MORITZ ECKARDT of No. 26 Falken Strasse in the City of Dresden and
Kingdom of Saxony, Engineer, do hereby declare the nature of my said 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 the closing of the packing of connected pistons in air and
other pumps, the object of which is to provide the cylinders with compressed air, or
gas so that the packing of the suction as well as the forcing piston is continuously
pressed on the walls of the cylinder in consequence of the special connection of the
pistons..
Figure 1 is a vertical section of the pump with one cylinder in section, the other in
elevation and the valve case in section.
Figure 2 represents the connected pistons partly in section and partly in elevation
on an enlarged scale.
Figure 3 is a section on the line X X in Figure 2 representing the application of a
flap instead of a sliding valve.
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Figure 4 is a vertical section through the piston connection on the line in
Figure 2.
A is the frame on which the pump is mounted, B is a casting which connects the
air chambers and the water mantle of the cylinders C C and to which the said
cylinders are securely attached. The cylinders are of like form and each provided
with a valve box cast onto the same containing the pressure valve T from whence the
compressed air enters into the air collector in the casting B which is in connection
with both cylinders whilst the suction valve P is arranged in the lid of the cylinder.

page_text: D and F Fare ways for the cooling water, Q.Q, are the outlet openings for the same
The pistons are connected by the beams and a as described later on in this
specification and receive their movement from a rod or lever J¹ on the fulcrum J the
upper end of the said rod or lever being connected to a rod K which in its turn is
connected to a crank L on the shaft to the strap drum M. The upper end of the
lever Jis bifurcated and embraces a slide or guide block the trunnions b₁ of which
have their bearings in the forked arms of the lever J¹. This slide or guide block b
can make a short upward and downward motion in a slot e in the massive part f of the
piston connection in order to be able to follow the movement of the lever J¹.
i
In order to lessen the friction and consequent wear and tear of the parts I employ a
device for supporting the center of the piston connection and taking up the weight of
the same. This device consists, as represented on an enlarged seale in Figure 2 and 4,
of a slide m which glides in the forked part of the lever J and can be fixed by means
of a bolt p. The piston connection is supported by a rod n which fits into a recess in
the massive part of the said connection so that when the piston makes its horizontal
movement and the lever J¹ moves on its pivot J all undue friction of the parts is
prevented by the rod n pressing upwards against the piston connection, said rod n being
provided with a suitable collar n¹ against which the helical spring presses. The
lower end of the rod n is supported by a adjustable block m attached to the two
forked arms of the lever J by means of the bolt and nut p. The piston and
cylinder are provided with hollow spaces which are connected on the one hand with
each other by means of a tube or hollow beam a and on the other hand with the air
space behind the piston by means of the valve N in each lid which said valve is
guided in the casing N¹ and can be opened and closed. The packing of each piston
consists of the leather collars c c, the weaker edges of which lay in an annular groove
of the piston and in an annular recess of the lid h. The cylindrical edge of the piston
on which the collar is placed is provided with slots c¹ in order that the packing may
be firmly pressed against the interior periphery of the cylinder and as the edges of
the collar are weaker than the other parts of the same a perfect closure is attained.
The packing can be compressed by means of the screw g around which the helical
spring dis arranged. In order to produce a rigid connection between the two
pistons and remove the active point of force, the connecting tube or hollow rod a
between the chambers of the two pistons is arranged eccentrically to the one side and
a massive rod a at the corresponding opposite side of the center of the piston. These
two rods a and a are connected in the center by means of a suitable bridge piece f,
said bridge piece being slotted to receive the aforementioned guide block b. If the
driving wheel or drum M is set in rotation in the direction indicated by the arrow in
Figure 1 the movement of the crank L will be transmitted through the rod K to the
lever J¹ so as to cause a movement of the piston in the direction from C to C¹
whereby the piston q'of the cylinder C sucks and the piston 7 of the cylinder C
presses.
In consequence of the air pressure created behind the piston r, the valve N will be
closed and compressed air flow into the hollow space of the piston and through the
tube a into the piston q, the compressed air passing through the slots c' of the piston
so as to firmly press the packing of the pistons and q against the walls of the
cylinders. In carrying out the reverse movement, the piston q will press and the
piston suck, the operation of the parts corresponding with that described above, i.e
the valve to the piston q will be opened and the valve to the piston r closed.
My improved pistons can be employed to great advantage in vacuum, air and other
pumps.
Having now particularly described my said invention and in what manner the
same is to be performed, I declare that what I claim is :—
1. In air and other pumps, the tube or hollow rod a for connecting the hollow
spaces in the pistons so as to firmly press the piston packing against the cylinder
walls by means of compressed fluid, substantially as and for the purpose set forth in
the foregoing specification and shown in the accompanying drawings.

page_text: 2. The device for taking up the weight of the pistons and their connection by means
of an adjustable rod n and a a helical spring, substantially as described in the foregoing
specification and shown in the accompanying drawings.
3. The combination of the hollow connection a and the air chambers in the pistons
with the valve N, substantially as and for the purpose set forth in the foregoing
specification and shown in the accompanying drawings.
Dated this and dane of Tann
1000
GEO. DOWNING,
Agent for Applicant.