An Improved Method of and Apparatus for Working Pressure
Year: 1888

page_text: [Communicated from abroad by WILHELM LORENZ, of 61, Kriegstrasse, of Karlsruhe,
in the Grand Duchy of Baden, German Empire, Engineer and Manufacturer.?
An Improved Method of and Apparatus for Working Pressure
I,, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the County
of Middlesex, Fellow of the Institute of Patent Agents, do hereby declare the nature
of this invention to be as follows:-
This invention relates to a method of and apparatus for working pumps, such as are
used for hydraulic presses or other machines where liquid under pressuro is applied,
in such a manner that the pump plunger is caused to exert an increasing pressure as
it makes its instroke until it reaches a maximum at or about the end of its stroke, at
which time it is moving very slowly.
For this purpose, the plunger of the pump instead of being connected directly
to the rotating crank, eccentric or cam which works it, is connected to one arm of
a toggle the other arm of which is jointed to the fixed framing, and the connecting
rod from the crank eccentric or cam is jointed to the middle of the toggle.
This connecting rod, reciprocating transversely, to the axis of the pump, bends
and unbends. the toggle, the pump plunger being thus made to reciprocate,.
moving rapidly with comparatively little force at and near the extreme of its outstroke,
and moving slowly with great force at and near the extreme of its instroke:
Dated this 13th day of September 1888.
ABEL & IMRAY,
Agents for the Applicant.

page_text: An Improved Method of and Apparatus for Working Pressure
Pumps,
I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane, in the County
of Middlesex, Fellow of the Institute of Patent Agents, 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:-
This invention relates to a method of and apparatus for working pumps, such as
are used for hydraulic presses or other machines where liquid under pressure is
applied, in such a manner that the pump plunger is caused to exert an increasing
pressure as it makes its instroke until it reaches a maximum at or about the end
of its stroke, at which time it is moving very slowly.
For this purpose, the plunger of the pump, instead of being connected directly
to the rotating crank, eccentric or a. cam which works it, is connected to one arın
of a toggle the other arm of which is jointed to the fixed framing, and the connecting
rod from the crank eccentric or cam is jointed to the middle of the toggle.
This connecting rod, reciprocating transversely, to the axis of the pump, bends and
unbends the toggle, the pump plunger being thus made to reciprocate, moving
rapidly with comparatively little force at and, near the extreme of its outstroke, and
moving slowly with great force at and near the extreme of its instroke.
Fig. 1 of the accompanying drawings shews an elevation of a pressure-pump
constructed according to my above described invention, in which the pump barrel
is arranged horizontally. A is the pump barrel, B the connecting rod with the
two pivot pins b₁, C the one link of the toggle pivotted at one end to the pin b
of the connecting rod and at the other end to a fixed pin c carried by the framing;
Cis the other link of the toggle pivotted at one end to the pin b1, and at the other,
end to the pin c¹ carried by the crosshead a of the pump plunger a¹.
The crank, connecting rod and toggle are shewn in their highest position, in
which the plunger is at the end of its outstroke, the pump barrel being filled with
liquid. On the rotation of the crank in the direction of the arrow, the toggle is
forced downward so as to be straightened out, and consequently in forcing the
plunger inwards, it acts with gradual increasing pressure upon the liquid in forcing
it to wherever required. Shortly before the links of the toggle pass through the
centre line of the pump, at the lowest position of the crank, a partial maximum
pressure will be attained, which is combined with a slight dwell as the crank passes
the lowest position and reverses the motion of the toggle, which will have passed
somewhat below the centre line. As the latter passes again through the centre
line on its return motion, the full maximum pressure is attained.
The period of pressure, that is to say, the working stroke of the plunger is
consequently of somewhat longer duration than the return or suction stroke.
Fig. 2 shews a diagram of the movement of the toggle during one revolution
of the crank, and Fig. 3 shews the corresponding pressure diagram.

page_text: The points o or 12 correspond to the commencement of the stroke, and the points 5
and 6 to the partial maximum, while the points 7 correspond to the full maximum
pressure.
In the above described construction the centre of the crank shaft is situated
vortically over the contre line between the connecting pins of the toggle links, when
these are in the highest position, in which the centre line through the said pins is
parallel with the centre line of the pump.
The centre of the crank shaft can be shifted somewhat from this position between
certain limits; for example, it may be placed so far to the right that it is
approximately perpendicularly over the centre of the line connecting the pins 661
when these are in the position which nearest coincides with the centre line of
the pump.
In this case the motion of the toggle links is somewhat altered, as shown at
Fig. 4, and the pressure diagram at Fig. 5.
In this case two equal maximum pressures are obtained, with a slightly decreased
pressure between them corresponding to the point 6.
The pump can also be arranged vertically or inclined. It is applied with advantage
for pressing or drawing tubes, metal cases, or other hollow bodies; for stamping or
compressing metals or other materials, for expressing liquids, and generally for pressing
objects or materials in which the work of pressing has to be effected with a gradually
increasing pressure and with either simple or double maximum and pressure.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim is
In pressure pumps, connecting tho piston or plunger of the pump to a crank and
connecting rod motion through a toggle whose links are connected respectively to
pins on the connecting rod and are so arranged as to exercise a gradually
increasing pressure on the piston or plunger, with either single or double maximum
end pressure, substantially as herein described.
Dated this 18th day of March 1889.
ABEL & IMRAY,
Agents for the Applicant.