Improvements in Hydraulic Lifts.
Year: 1893

page_text: Date of Application, 21st Nov., 1893-Accepted, 31st Mar., 1894
COMPLETE SPECIFICATION.
Improvements in Hydraulic Lifts.
We JOSEPH STANNAH and GEORGE PINKER Engineers 20 Southwark Bridge
Road, London, S.E. 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:-
Our invention relates to that class of lift in which the cage and load are raised
by a direct ram, fixed under the cage, and raising the same without the intervention
of chains or pulleys.
The ram having usually to be made larger in diameter for the sake of strength,
than is necessary to raise the load, there is a corresponding loss of water which it
is the object of our invention to prevent.
To effect this we employ an auxiliary apparatus, comprising a cylinder in which
works a hollow main ram, which in turn works upon a hollow fixed plunger, which
is fixed at the top to a crosshead, the crosshead being fixed to the base plate of the
main cylinder by stretchers or staye. The main cylinder is in free communication
with the working cylinder of the lift, so that as the cage ascends and descends, the
water flows from one to the other and is not consumed. The hollow fixed plunger
is bored and is fitted with a piston or plunger, also hollow, which is bolted to the
bottom of the main ram, a turned pipe passes through the piston or plunger, and is
in free communication with the interior of the main hollow ram, there are therefore
two chambers, the outer or larger one, and the inner or smaller one.
By means of a suitable valve or valves, water from the accumulator may be
admitted to one, or both of these chambers, if admitted to one the main hollow ram
is driven down exerting only a portion of its power, if admitted to both, the said
ram is driven down exerting the full power for which the apparatus is constructed.
Suitable valves are fully described in Pinker's Specification No. 2907 of 1889.
The main hollow ram may be loaded with weights to partly counterbalance the
weight of the lift cage and direct acting ram. Suitable packing is fitted to keep
the rams and pistons water tight.
By means of this invention, direct acting lifts, and other similar hoisting apparatus
may be made with either 2 or 3 powers and a large saving effected in the consumption
of water.
The accompanying drawings illustrate our invention, the same letters indicate
similar parts in each figure.
ram,
Fig. 1 is a vertical section of the apparatus, Fig. 2 is a front elevation, Fig. 3 is
a plan. A is the cylinder in communication with the main lifting cylinder and
by means of the outlet x, is the main hollow ram, G is the hollow fixed
plunger, which is bored to receive the piston or plunger d, F is the turned pipe,
passing watertight through the piston d, to conduct the water into the larger
chamber g, a hole is drilled in the hollow plunger d to allow the water to pass
into the chamber g, E is a saddle piece resting on a collar formed upon the main
hollow ram b, the weights W, W, being suspended to the saddle piece by means of
bolts, K K. L is the crosshead to which is bolted the hollow fixed plunger G,
and the turned pipe F, o is the smaller chamber, and M, N, are the inlets to the
larger and smaller chambers respectively. P. P, are the iron stretchers or stays
to fix the crosshead to the base plate or other part of the main cylinder.
The necessary stuffing boxes and cup leathers are shewn in the drawing.
It will be seen that the cylinder A, the ram G, and pipe F, being fixed and
remaining stationary, the ram b and the piston or plunger d with the loading W, W
are free to work up and down. The lift must be constructed so that the cage and

page_text: direct acting ram would have a portion of their weight unbalanced by the
loading W, W, and other moving parts of the auxiliary apparatus, so that when
the empty cage is at the top or in any other position by moving the valve so that
the pipes M and N with the corresponding chambers and are open to the
exhaust, the ram b will rise and the cage will travel downwards. The cage on
coming to the bottom automatically closes the supply port or ports connected to
inlet M or inlets M and N as the case may be, so that the working parts of the
lift are practically brought into the same relative position as when the downward
travel of the cage is stopped by the operator closing these ports.
To raise the cage alone or with a light load, the supply port connected to the
inlet M is opened the water passes through the pipe F into the chamber g which
causes the ram b to descend and the cage with its load to ascend, to stop it at any
point the valve is moved so as to close this supply port the exhaust port remaining
closed which causes the ram b and the cage to remain stationary. To raise, hold
in position, or lower the cage with its full load the valve or valves are so arranged
that the operator can by means of the rope or lever fill or empty the chambers g
and o simultaneously or either process might be stopped at any point by simul-
taneously closing whichever port or ports are open.
Having now particularly described and ascertained the nature of our said
invention we declare that what we claim is :-
:-
1. The arrangement of rams and cylinders as herein illustrated and described for
the purpose of obtaining two or more powers for an hydraulic lift or hoist.
2. The arrangement of the turned pipe F and of the hollow piston or plunger d,
with the perforations h to admit water into the chamber 9.
3. The arrangement of a variable power balance cylinder as herein described
and illustrated.
Dated this 21st day of November 1893.
JOSEPH STANNAH.
GEORGE PINKER.