IMPROVEMENTS IN HYDRAULIC LIFTS to be as follows:
Year: 1884

page_text: I GEORGE HUTCHINSON of Elswick Works Newcastle upon Tyne Engineer do
hereby declare the nature of my invention for "IMPROVEMENTS IN HYDRAULIC
LIFTS to be as follows:-
"
This invention has for its object improvements in hydraulic lifts.
In hydraulic lifts it is common to employ in addition to the main rams by
which the platform or cage is lifted other rams for the purpose of carrying most
of the dead weight of the platform or cage and other parts. Such counterbalance
rams work in cylinders which are constantly in communication with an accumu-
lator or other source. -
According to this invention use is made of the counterbalance rams to check
the tipping of the platform or cage such as might be liable to occur from unequal
loading or unequal friction or resistance in its guides.
The cylinders in which the counterbalance rams work are connected each with
a separate accumulator cylinder and the rams of these several accumulators are
made.to carry one common load or counterpoise.
The equable movement of the several accumulator rams is thereby ensured and
under all conditions likely to occur in practice an equable movement of the
counterbalance rams carrying the platform or cage will necessarily result.. Under
some conditions it may be advisable in like manner to connect, the cylinders of the
lifting rams each with a separate accumulator cylinder and to apply one common
load to all rams.
1
000

page_text: I GEORGE HUTCHINSON of Elswick Works Newcastle upon Tyne Engineer do
hereby declare the nature of my invention for "IMPROVEMENTS IN HYDRAULIC
LIFTS and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention has for its object improvements in hydraulic lifts.
In hydraulic lifts it is common to employ in addition to the main rams by which
the platform or cage is lifted other plungers or rams for the purpose of carrying
most of the dead weight.
It is to such lifts that my invention alone applies and in such lifts I make use of
the counterbalance rams to check the tipping of the platform or cage.
The cylinders in which the counterbalance rams work are each connected with a
separate accumulator cylinder and the rams of the accumulator cylinders are
coupled together and made to carry a common load or loads.
In order that my, said invention may be most fully understood and readily
carried into effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation. Figure 2 is an end elevation and Figure 3 is a plan
of an hydraulic lift suitable for transferring railway trains from one level to
another.
a. a. is the platform or cage which receives the train. b. b. b. b. are.four rods
connecting the platform or cage with counterbalance rams working in four counter-
balance cylinders c. c. c. c. and d. d. are rods connecting the platform or cage with
lifting rams working in cylinders e. e. into which water is forced by pumps when
it is desired to raise the platform or cage and from which water is allowed to
escape when the platform or cage is to be lowered. ff. ff. are the cylinders of
an accumulator with which the cylinders c. c. c. c. communicate each with each as
is indicated by dotted lines. g is the load on the accumulator rams and which
'they all support in common. The accumulator rams being thus connected to one
weight case must therefore rise and fall together consequently the counterbalancing
cylinders must also work together and the parallelism of the hoist platform must
be preserved in ascending and descending. The object of having two counter-
balancing cylinders at each end is for additional safety. Each would be designed
to take the full weight by itself. In this arrangement the connections are such as
to ensure only the horizontality of the cradle in a longitudinal direction, guides
being provided to keep it level in a transverse direction.
In the arrangement shown in Figures 4, 5 and 6 the connections are such that
tipping is restrained both in the longitudinal and transverse directions. c¹ c² c³
and care the counterbalancing cylinders c¹ and c³ being in communication with
separate accumulator cylinders f¹ and f³ the rams of which are attached to one
weight case c² and c being similarly in communication with another twin accu-
mulator ff. All four accumulator cylinders might of course be under the same
weight case but in that case any escape of water from one cylinder would result
in a bending or "racking" of the platform whereas by connecting only those at
opposite corners this "racking" is avoided and the only result of leakage would
be that one corner of the cradle would be slightly depressed which could readily
be detected and put right by pumping in water to make up that which had escaped.

page_text: In the arrangement first described there would be the same tendency to
"racking" if water escaped from one cylinder, but in this case it would not be of
much importance.
If. considered desirable the cylinders c, c, diagonally opposite might be connected
to one twin accumulator and the other diagonally opposite cylinders to the other
thus assimilating the arrangement to that last described.
It is obvious that there are many different ways in which the principle might be
carried out. Those described above are only selected as instances.
I would remark that I am aware that it has before been proposed to provide
Counterbalance plungers or rams beneath the platform or cage and to connect the
cylinder of each of these plungers or rams with a separate accumulator cylinder.
The accumulator plungers or rams carried a common load which preponderated
over the platform or cage and other lifting rams were provided beneath the
accumulator load to lift it when it was desired that the platform or cage should
descend. This arrangement I do not claim; it requires that a very heavy accumu-
lator load should be employed and the cost of the structure is thereby increased.
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
.
An hydraulic lift in which there are two sets of rams carrying the weight of
the platform or cage; one set being counterbalanced rams supporting the greater
part of the dead weight and the other set being lifting rams which operate to lift
the platform or cage with its load; and in which also the cylinders of the counter-
balance rams are connected with separate accumulator cylinders such accumulator
cylinders receiving coupled rams supporting a common load or loads substantially
as described.