Year: 1886

page_text: Date of Application, 18th Nov., 1886.
Complete Left, 21st Feb., 1887.
Complete Accepted, 22nd Mar., 1887.
We, HENRY CLAUDE WALKER and ROBERT CAREY both of the Newington Iron
Works Falmouth Road London S.E. Engineers do hereby declare the nature of this
invention to be as follows :-
Our invention relates to improvements in direct acting hydraulic lifts of the single
acting class in which the pressure water acts on the up stroke the return stroke being
effected by gravity.
Our invention has for its object the balancing or rendering more uniform of the
nett pressure of water and also an improved arrangement of the counterbalance.
In an ordinary vertical direct acting lift the pressure on piston or end of ram varies
as the piston or ram rises or falls this variation being due to the difference in the
head of water at the various parts of the stroke. In long stroke cylinders this may
amount to many pounds on the square inch and although with high pressure water this
may not be of much consequence yet with low pressure water it causes the minimum
pressure to be very much less than the maximum pressure proportionately.
To obviate this we preferably construct our apparatus as follows:-
We bore the cylinder and provide it with a watertight piston. We close the bottom
end of the cylinder and admit the pressure water thereto the inlet and outlet of the
water being controlled by a suitable valve or valves. The upper portion is kept full
of water obtained either from the exhaust out of the lower portion or from any other
convenient source.
The water flows away from the top of the cylinder as the piston ascends so that
the pressure on top of piston decreases as the pressure below decreases thus keeping
the nett pressure almost uniform. The water flows in to the top of cylinder as the
piston descends the pressure above increasing as the pressure below increases again
keeping the nett pressure almost uniform this advantage being most apparent in cases
in which the cylinder is arranged in a pit and the exhaust water has to be delivered
some distance above the bottom of cylinder.
When the piston rod is constructed hollow we preferably provide apertures in it
immediately above the piston so that the water can rise within the rod to the same

page_text: level as the water in cylinder and by this means get a working area above the piston
almost equal to the area below.
When the counterbalance chains are connected to the cage as in lifts in general use
a considerable strain is put on the connection between cage and ram or piston rod
causing it sometimes to give way. In the hoist or lift of our invention we connect
the chains or ropes preferably direct to the piston carrying them up the inside of
cylinder over sheaves at the top and fixing them to the counterbalance which travels
up and down the cylinder pit or in any other convenient place.
The above invention is described as applied to a vertical cylinder but it will be
evident that it is also applicable when the cylinder is arranged at an angle.
Dated this 18th day of November.
HENRY C. WALKER.
ROBT. CAREY.
We HENRY CLAUDE WALKER and ROBERT CAREY both of the Newington Iron
Works Falmouth Road London S.E. Engineers do hereby declare the nature of our
said 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 improvements in direct-acting hydraulic lifts of the single-
acting class in which the pressure water acts on the up stroke the return stroke being
effected by gravity.
In an ordinary vertical direct-acting lift the pressure on piston or end of ram varies
as the piston or ram rises or falls this variation being due to the difference in the
head of water at the various parts of the stroke. In long stroke cylinders this may
amount to many pounds on the square inch and although with high pressure water
this may not be of much consequence yet with low pressure water it causes the
minimum pressure to be very much less than the maximum pressure proportionately.
The piston or ram in its descent has to force out the water from the cylinder. This
puts on the piston or ram a varying back pressure and the cage etc must therefore
have enough unbalanced weight to overcome the maximum back pressure which
attained at the bottom of the stroke. This unbalanced weight has to be lifted
together with the load when the cage ascends thus causing the gross weight to very
much exceed the nett weight lifted,

page_text: To obviate this we preferably construct our apparatus as follows:-
We bore the cylinder and provide it with a watertight piston. We close the bottom
end of cylinder and admit the pressure water thereto the inlet and outlet of the
water being controlled by a suitable valve or valves. The upper portion is kept full
of water obtained either from the exhaust out of the lower portion or from any other
convenient source.
The water flows away from the top of cylinder as the piston ascends so that the
pressure on top of piston decreases as the pressure below decreases thus keeping the
nett pressure almost uniform. The water flows in to the top of cylinder as the piston
descends so that the pressure on top of piston increases as the pressure below increases
again keeping the nett pressure almost uniform.
With this arrangement the unbalanced weight of cage need be little more than is
requisite to overcome the friction of the apparatus as the piston in its descent is almost
in equilibrium and therefore the gross load to be lifted exceeds the nett load only by a
small amount.
When the counterbalance is connected to the cage as in lifts in general use a
considerable strain is put on the connection between cage and ram or piston rod
causing it sometimes to give way. In the lift of our invention we connect the chains
or ropes preferably direct to the piston carrying them up the inside of cylinder over
sheaves at the top and fixing them to the counterbalance which travels up and down
the cylinder pit or in any other convenient place.
In the accompanying drawing the same letters indicate the same parts and the
different views shew the forms in which we preferably carry out our invention.
Fig. 1. is a general elevation and Fig. 2. a sectional elevation to an enlarged scale
of the upper part of cylinder of Fig. 1. These views have reference to both the first
and second parts of our invention and shew them as applied to a vertical direct-acting
lift with the cylinder and counterbalance arranged in a pit. In this case the exhaust
water is delivered at or below the level of top of cylinder.
Fig. 3 shews another arrangement of the first part of our invention as applied in
cases where it is convenient or necessary to deliver the exhaust water above the level
of top of cylinder. We have also for the sake of illustration shewn the top of cylinder
in communication with a tank instead of with the valve or valves as shewn in Fig. 1.
In Fig. 3. the second part of our invention is omitted and the cage is presumed to
be balanced in the ordinary manner although if desirable the counterbalancing arrange-
ment shewn in Figs. 1. & 2 could be substituted and stuffing boxes provided for the
ropes to work through.
A is the cylinder provided with a cover a at its lower end.
B is the piston made watertight with a cupped leather b.
C is the hollow piston rod guided at c¹ and having holes c to allow the water to rise
within it.
d
D is the counterbalance attached to the piston B by means of ropes & passing over
sheaves d¹.
E is the controlling valve operated by hand ropes e.
F is a pipe communicating between valve E and lower part of cylinder and ƒ is a
pipe communicating between valve E and upper part of cylinder.
G is a tank arranged in Fig. 3 to receive the water from upper part of cylinder.
The mode of operation of our invention when arranged as in Figs. 1 & 2 is as
follows
When it is required to lower the cage the upper and lower portions of the cylinder
are put into communication by means of the rope e operating the valve E so that
the piston descends by gravity forcing the water out of the lower into the upper
portion of cylinder excepting the amount displaced by the metal forming the
piston rod which flows away down the exhaust pipe. By this arrangement the nett
pressure of water on piston is kept almost constant during its stroke and descends at
an almost uniform speed.
When it is required to lift the cage the lower portion of the cylinder is by means
of the valve E put into communication with the supply and the upper portion with

page_text: the exhaust pipe. The water flows away from the top of cylinder as the piston
ascends so that the pressure on top of piston decreases as the pressure below decreases
thus keeping the nett pressure almost uniform.
When the upper portion of cylinder is connected to a tank as shewn in Fig. 3. the
water is admitted from the supply pipe to the lower portion when it is required to lift
the cage and allowed to flow away into the exhaust pipe when it is required to
lower it.
In the accompanying drawing the piston rod is shew hollow and is thus preferably
constructed although in some cases we use a solid rod as for instance in the case of a
light lift with a short stroke.
In the accompanying drawing the counterbalance is shewn annular and suspended
by two ropes but it could obviously be of any other convenient shape or be suspended
by one or more chains or ropes or be arranged in any convenient place other than
the cylinder pit when considered desirable.
We also do not confine ourselves to use the tank with close topped cylinders as
shewn in Fig. 3. but may use it with open topped cylinders shown in Fig. 2. and
conversely may use the close topped cylinders with any suitable valves without the
tank.
Having now particularly described and ascertained the nature of our invention and
in what manner the same is to be performed we wish it to be particularly understood
that we do not confine ourselves to the exact details here described and illustrated but
we do declare that what we claim is :-
1. The balancing or rendering more uniform of the nett pressure on pistons of
direct acting lifts by keeping the upper portion of cylinder full of water from the
exhaust out of lower portion for the purposes hereintofore described.
2. The balancing or rendering more uniform of the nett pressure on pistons of
direct acting lifts by keeping the upper portion of cylinder full of water taken from
tanks or any convenient source other than the supply pipe for the purposes hereintofore
described.
3. In hydraulic lifts the attaching the counterbalance direct to the piston or bottom
of piston rod adjacent to the piston instead of to the cage or other portion.
Dated this 21st day of February 1887.