IMPROVEMENTS IN HYDRAULIC APPARATUS APPLICABLE FOR RAISING AND LOWERING BRIDGES, CANAL LIFTS, GUNS, AND OTHER HEAVY PROVISIONAL SPECIFICATION
Year: 1873

page_text: LETTERS PATENT to Josiah Latimer Clark and John Standfield,
both of 5, Westminster Chambers, Victoria Street, Westminster, for
the Invention of "IMPROVEMENTS IN HYDRAULIC APPARATUS APPLICABLE
FOR RAISING AND LOWERING BRIDGES, CANAL LIFTS, GUNS, AND OTHER HEAVY
PROVISIONAL SPECIFICATION left by the said Josiah Latimer Clark
and John Standfield at the Office of the Commissioners of Patents,
with their Petition, on the 19th July 1873.
We, JOSIAH LATIMER CLARK and JOHN STANDFIELD, both of 5,
Westminster Chambers, Victoria Street, Westminster, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN HYDRAULIC
Apparatus ApplicABLE FOR RAISING AND LOWERING BRIDGES, CANAL LIFTS, GUNS,.
AND OTHER HEAVY WEIGHTS:”–

page_text: weight of the machinery which has to be raised and lowered is constantly
balanced, so that only a small additional power is required to give it
motion.
(In the following description we call the rams of the presses of the
accumulator "plungers" and those of the hydraulic press "rams.") To
effect this we construct an accumulator with two, three, or more
plungers. We usually prefer to employ three plungers, two of which are
of such dimensions as to produce exactly sufficient pressure on the ram
of the hydraulic press to balance the dead weight of the machinery
carried by it. In this condition the accumulator and the hydraulic
press are in equilibrium, and a very small increase or decrease of
pressure suffices to cause the hydraulic ram to ascend or descend, as the
case may be, an extra load is then put on the accumulator sufficient to
cause it to descend and to raise the hydraulic ram with any desired load
upon it. The third plunger is placed centrally under the head of the
accumulator and is so connected by pipes with the two outer plungers
that all three can be placed into connection at will. If the accumulator
is down, and the ram elevated as just described, and the communication
is opened between the three plungers the weight of the accumulator
which was at first supported by two plungers being now supported by
three, the pressure on the water is diminished and consequently the
accumulator ascends and the ram descends. In order to raise it again it
is only necessary to allow the water to escape from the central ram when
the whole weight becomes supported on the two plungers as before and
the pressure is consequently increased and the ram again ascends. A
small pump is employed to keep the accumulator charged in the usual
manner.
The arrangement above described may be reversed and the rams made
differential instead of the accumulator. In this case the accumulator is
of the ordinary character but the rams are arranged threefold or fourfold,
and the connections are arranged as before described in the case of the
accumulator, that is to say, when only one or two rams are connected,
as the case may be, the rams descend and force back the water in their
cylinders into the accumulator, but when all the rams are connected
with the accumulator the rams ascend and the load is raised.
In order still further to diminish the loss of power entailed when
raising and lowering heavy weights by hydraulic rams we also compen-
sate for the varying immersion of the rams.

page_text: When a ram is raised in the ordinary manner it is evident that as
the ram ascends out of the water into the air it increases in weight, and
its force or power diminishes by an amount which is equal to the
weight of a column of water of its own bulk, and similarly as the
plunger of an accumulator descends it also loses a power equal to
the bulk of the column of water which it displaces, and both of these
actions concur to diminish the power of the machine more and more as
it approaches the full extent of its stroke. To obviate this evil we
employ a compensator which is thus constructed. It consists of a ram
or cylinder resting on the cross head of the accumulator and rising and
falling with it, its upper portion passes through a water-tight joint in the
bottom of a tank which is filled with water, so that the whole of the
ram within the tank is under water. The sectional area of this ram is
equal to twice the sectional area of all the plungers of the accumulator.
The action of this ram is as follows:-When the accumulator is up and
the top of the ram nearly or quite level with the surface of the water in
the tank, there is no pressure upon it tending to force it downwards,
except its own weight, but when it is down near the bottom of the tank,
the pressure of the column of water above it is increased in proportion to
its degree of immersion, thus compensating exactly for the loss of
the weight of the plungers caused by their immersion and the increased
weight of the ram caused by its emergence out of the water. By these
arrangements the whole of the dead weight of the machine itself is
perfectly counterpoised in every position, and the only power required
to work the machine is that requisite to raise the load itself and to
overcome friction.
Where it is desirable that two or more rams should ascend syn-
chronously through equal distances, as in the instance of the two ends.
of a bridge or canal lift, we combine two or more plungers into a group
beneath one accumulator, so that as the plungers descend all the rams
ascend through uniform distances.
To prevent the danger and inconvenience which arises from the
leather of a ram or plunger giving way during use, we employ two or
more leathers arranged one above the other with a warning pipe fitted
between them. The strain is ordinarily borne by the lower leather, but
if this wears away or bursts the strain comes upon the upper one, and
at the same time the water rushing out of the warning pipe gives notice
of the failure of the leather; a tap or valve fixed in this pipe is then.

page_text: closed so as to prevent further escape nntil a convenient opportunity
arises for removing the damaged leather.
This Invention is applicable with great advantage to most of the
purposes for which hydraulic presses are ordinarily employed. It is
especially adapted for military and naval purposes for the raising, lowering,
and rapid manipulation of heavy guns. In applying the principle to
guns we cause the frame or platform carrying the gun to be supported
on a hydraulic press or presses, and to be balanced in equilibrium by
'means of an accumulator of the form described. The gun is loaded
while at the lower level, and is rapidly raised with its platform when it
is fired, suitable provision being made for revolving it when either up or
down. This is effected by small horizontal hydraulic presses on the
'platform connected with the main press, and supplied from it by
pipes.
One accumulator may be made to balance and work any number of
guns, being kept pumped up by a small engine. Both may be placed in
any convenient position at a distance from the guns. Or the traversing
platform and gun may ascend up and down a steeply inclined plane by
means of rails and rollers. The gun and its platform are balanced in
equilibrium with the accumulator, and are capable of being imme-
diately elevated or lowered by the turning of a handle. The platform
carries a revolving table for turning the gun into any azimuth, and its
breech may rest on a small hydraulic press, by which it can be raised or
lowered to any angle. Both these movements are produced by hydraulic
pressure, the requisite connections being made with the hydraulic ram,
which raises and lowers the gun. It is equally applicable for raising
and lowering mantlets in the front of guns or iron turrets, the mantlets
or turrets being supported in equilibrium on the hydraulic machinery,
and capable of being raised and lowered at pleasure, as before
described.
In raising or lowering bridges over rivers, canals, and docks the bridge
is supported on presses in equilibrium, as before described, and when a
vessel is desired to pass the bridge is either submerged under water to a
*sufficient depth to allow the vessel to pass over it, or elevated in the air
sufficiently high for the vessel to pass beneath it.
In order to cause both ends of a bridge or other moving apparatus to
ascend or descend in a horizontal position we fix shafting and pinions

page_text: on the bridge, which engage in fixed racks at the ends of the bridge, and
compel both ends to rise and fall at the same speed.
In longer bridges and larger apparatus we employ an arrangement
consisting of a horizontal revolving shaft and pinions engaging in rack-
work, as described in Mr. Edwin Clark's Patent, No. 611, dated 18th
February 1873; but in place of bevelled gearing we cause the horizontal
shaft to carry at each end a pinion engaging in the fixed rack work.
These pinions are not keyed on the shaft, but fit with a loose screw on
its ends, the one screw being right handed, and the other left handed. So
long as the bridge carrying both pinions and the shaft rises uniformly
they rotate at the same speed, and no effect is produced; but if either
end becomes elevated above the other its pinion unscrews itself, and
traverses laterally along the shaft, and in doing so opens a valve, and
allows water to escape from the ram, and continues to do so until the
level is again attained.
In forming excavations, raising minerals, and other cases in which it
is necessary to raise carriages, trucks, or wagons from one level to
another we prefer to place the platform carrying the truck to run
upon rails in a steep inclined plane, the said platform being balanced
in equilibrium with an accumulator, as before described. It is also
applicable for raising vessels on pontoons, and for canal lifts. The
differential accumulator is also suitable for working hydraulic presses of
a telescopic form, that is to say, one press working within the other.
The plungers of the accumulator are so arranged that three plungers are
used for the first and largest press, and only one or two plungers for the
second lift, or such other number as may be required.
;
For conveniently renewing the leathers of a press we employ a gland
of peculiar construction. The press is furnished inside with a number of
vertical slots descending for a few inches, and the gland is provided with
a similar number of projections, which fit into these slots at the bottom
of all these slots. An annular ring is turned out of the press, so that
when the gland is fully inserted it can be turned round through a small
portion of a circle, so that each projection locks bayonet fashion under
the metal projections of the press.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Josiah Latimer Clark and John Standfield in the
Great Seal Patent Office on the 19th January 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOSIAH
LATIMER CLARK and JOHN STANDFIELD, both of 5, Westminster
Chambers, Victoria Street, Westminster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of July, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Josiah Latimer Clark and John Standfield,
Her special license that we, the said Josiah Latimer Clark and John
Standfield, our executors, administrators, and assigns, or such others as
we, the said Josiah Latimer Clark and John Standfield, our executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter, during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN HYDRAULIC APPARATUS APPLICABLE FOR RAISING AND LOWERING BRIDGES,
CANAL LIFTS, GUNS, AND OTHER HEAVY WEIGHTS," upon the condition
(amongst others) that we, the said Josiah Latimer Clark and John
Standfield, our executors or administrators, by an instrument in writing
under our, or their hands and seals, or under the hand and seal of one
of us or them, should particularly describe and ascertain the nature of
the said Invention and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that we, the said Josiah Latimer Clark and John
Standfield, do hereby declare the nature of the said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement thercof, that is
to sav

page_text: of the machinery which has to be raised and lowered is constantly
balanced so that only a small additional power is required to give it
motion.
(In the following description we call the rams of the presses of the
accumulator "plungers" and those of the hydraulic press "rams.") To
effect this we construct an accumulator with two, three, or more
plungers. We usually prefer to employ three plungers, two of which
are of such dimensions as to produce exactly sufficient pressure on the
ram of the hydraulic press to balance the dead weight of the machinery
carried by it. In this condition the accumulator and the hydraulic press
are in equilibrium, and a very small increase or decrease of pressure
suffices to cause the hydraulic ram to ascend or descend, as the case may
be. An extra load is then put on the accumulator sufficient to cause it
to descend and to raise the hydraulic ram with any desired load upon it.
The third plunger is placed centrally under the head of the accumulator,
and is so connected by pipes with the two outer plungers that all three
can be placed into connection at will. If the accumulator is down and
the ram elevated as just described, and the communication is opened
between the three plungers, the weight of the accumulator which was
at first supported by two plungers being now supported by three the
pressure on the water is diminished, and consequently the accumulator
ascends and the ram descends. In order to raise it again it is only
necessary to allow the water to escape from the central ram, when the
whole weight becomes supported on the two plungers as before, and the
pressure is consequently increased and the ram again ascends. A small
pump is employed to keep the accumulator charged in the usual
manner.
In order still further to diminish the loss of power entailed when
raising and lowering heavy weights by hydraulic rams we also compen-
sate for the varying immersion of the rams.
When a ram is raised in the ordinary manner it is evident that as the
ram ascends out of the water into the air it increases in weight, and its
force or power diminishes by an amount which is equal to the weight of
a column of water of its own bulk, and similarly as the plunger of an
accumulator descends it also loses a power equal to the bulk of the
column of water which it displaces, and both of these actions concur to
diminish the power of the machine more and more as it approaches the

page_text: full extent of its stroke. To obviate this evil we increase the load on
the accumulator as its plunger descends by a weight of water sufficient
to compensate for the varying immersion of the plunger and of the ram
of the press. By this means the whole of the dead weight of the
machine itself is perfectly counterpoised in every position, and the only
power required to work the machine is that requisite to raise the load
itself and to overcome friction. We also by the same means are enabled
to give increased power at the end of the stroke by adding to the load a
greater weight of water than is required for compensating for the
varying immersion of the rams and plungers, or conversely decreased
power may be given at the end of the stroke by causing weighted tanks
or vessels which form the load of the accumulator to descend into
water.
Where it is desirable that two or more rams should ascend synchro-
nously through equal distances, as in the instance of the two ends of a
bridge or can lift, or in raising guns, &c., we combine two or more
plungers into a group beneath one accumulator, so that as the plungers
descend all the rams ascend through uniform distances.
In order to cause all four corners of a bridge or other moving
apparatus which is supported by presses at its two ends to ascend or
descend in a horizontal position we provide means for allowing an
escape of water from beneath either of the rams if from any cause one
of them should become elevated above the other.
To prevent the danger and inconveniece which arises from the leather
of a ram or plunger giving way during use, we in some cases employ two
or more leathers arranged one above the other with a warning pipe fitted
between them. The strain is ordinarily borne by the lower leather, but
if this wears away or bursts the strain comes upon the upper one, and at
the same time the water rushing out of the warning pipe gives notice of
the failure of the leather. A tap or valve fixed in this pipe is then
closed so as to prevent further escape until a convenient opportunity
arises for removing the damaged leather.
For conveniently renewing the leathers of a press we employ a gland
of peculiar construction. The press is furnished inside with a number
of vertical slots descending for a few inches, and the gland is provided a
with a similar number of projections which fit into these slots. At the
bottom of all these slots an annular ring is turned out of the press, so

page_text: that when the gland is fully inserted it can be turned round through à
small portion of a circle, so that each projection locks bayonet fashion
under the metal projections of the press.
In order that our said Invention may be fully understood and readily
carried into effect, we have shewn in the Drawings hereunto annexed
various examples of hydraulic apparatus arranged according to our
Invention.
Figure 1 shews an accumulator such as herein-before first described
used for raising and lowering a gun.. The accumulator is constructed
with 3 presses A³, B', A³, and 3 plungers A, B, A. They are loaded
with the weight W which is so adjusted as to balance the gun G,
supported on the press C¹ and its ram C. The plungers A, A, are of
such dimensions that when loaded with the weight. W. and connected
jointly with the ram C they just balance the weight of the gun G, which
is therefore free to be raised or lowered without any power except that
necessary to overcome friction. When this equilibrium has been
obtained a small additonal weight W' is added on to the accumulator,
which consequently descends and elevates the gun G to its full height.
All this time the plunger B is out of action and is merely connected by
a pipe with the supply reservoir. If it be desired to cause the gun to
descend the tap D in connection with the small plunger B is opened so
as to place all three plungers in communication: The pressure' being
now distributed over all three plungers instead of only two causes the
weight W to ascend and the gun G to descend. If it be again required
to raise the gun G it is only necessary to close the tap D, and the
weight of the accumulator coming only on the two plungers A, A,
again causes the gun to ascend as before. The water under the small
plunger B being as before allowed to return back into the supply
reservoir. In this way the gun G may be raised and lowered at pleasure
by the mere turning of the tap D, and the only power wasted is that of
the small plunger B which is made of such size as to be just sufficient
to overcome the necessary friction. It is evident that the same effect of
obtaining a slight variation of pressure in the accumulator may be
produced by either allowing the weight W' to rest on the weight W or
holding it off therefrom, and this may be done in many ways. For
example it may be effected by the central plunger in the manner
indicated by the dotted lines x, thus if water under pressure is introduced
below the central plunger and the weight Wi raised the gun will

page_text: descend, but if the weight W¹ is allowed to rest upon the weight W, the
accumulator will descend and the gun again rise.
It is also evident that the central plunger B may be operated from any
independent source of pressure without having any communication with
A and A. In this case the weight W is made heavier than the weight
or gun to be moved, and in order to cause the gun to descend pressure
is applied to the centre plunger B, and thus the weight W may be made
to rise and fall at will. These principles apply to all the cases hereafter
described.
If instead of raising and lowering a fixed weight G it be desired to
raise a load which is removed at the top, such as a wagon of earth, &c.,
it is only necessary to increase the weight W₁ to sufficient extent and to
increase the size of the plunger B. The ram will then ascend with its
load, and when it is deposited at the top it can be caused to descend by
opening the tap D in the same manner as before.
In order still further to diminish the loss of power entailed in raising
and lowering heavy weights by hydraulic rams we also compensate as
above stated for the varying immersion of the rams and plungers at all
parts of their stroke by increasing the load on the accumulator as its
plungers descend. At Figure 2 we have shewn an accumulator con-
structed in a suitable manner for effecting this object. A¹, B¹, A¹, and
A, B, A, are the presses and plungers of an accumulator such as that
before described. A tank of water T is fixed above the accumulator,
and a compensating plunger M works through a leather collar in the
bottom of the tank and rests upon the top of the accumulator. The
upper portion of the plunger M is always under water, and its sectional
area is equal to twice the sectional area of the plungers A, B, A, and it
may be either solid or hollow. When the plungers are at the bottom of
their stroke the compensating plunger M is at the bottom of the tank
and supports the whole weight of the column of water above it, but
when the plungers are at the top of their stroke the top of the compen-
sating plunger is near the surface of the water, and consequently supports
no pressure except that of its own weight.
If the proportions above named be carried out it follows that at every
part of the stroke, whatever be the number or dimensions of the plungers
or rams, they will always be compensated at every portion of the stroke.
We also compensate for the rise and fall of the water in the tank T,

page_text: caused by the rise and fall of the plunger in it by making the plunger M
a little larger than the proportions before stated in the ratio which its.
sectional area bears to that of the tank, so that if the area of the tank
be 10 times that of the compensating plunger M we make the latter
5th larger than the proportions above given. For example let a be
the area of all the plungers, & the area of the tank, and m the area of
the compensating plunger, its size when adjusted for perfect equilibrium
should be m = 2a + (2 a × 7). In this case the equilibrium of the
apparatus will be absolutely perfect at every portion of the stroke.
Figures 3 shew a modification of this arrangement in which the
compensation is effected by a fixed syphon S supported by the tank T..
The accumulator, in addition to its weighted load W, carries a compen-
sating water tank M, which rises and descends with it. The syphon S
dips into this tank, and as it descends the tank becomes filled with water
and its weight increased, and when it ascends the water flows back again.
through the syphon S, and the load is diminished so as to preserve the
equilibrium at all points of the stroke. If a be the area of the plungers, t
the area of the tank, and m the area of the compensating tank, the
proper size for this tank when adjusted for perfect equilibrium will be
m = 2a + (2 a × m³).
At Figure 4 is shewn a modification of this arrangement in which the
accumulator is constructed to commence with a small pressure, and
finish with a heavy pressure, as is required when pressing cotton and
such like. M is the compensating tank shewn at the top of its stroke,
and nearly empty. In this position the pressure on the accumulator is
small; it is also shewn in dotted lines at M³, M², at the bottom of its
stroke. It is then full of water, and the pressure on the accumulator is
at a maximum. It is obvious that by making the tank conical or of any
other variable shape varying degrees of pressure can be obtained at
different parts of the stroke at pleasure.
The converse of the above arrangement is shewn at Figure 5. In
this Figure the compensating tank M, M, is again shewn at the top of
its stroke, and in this position it gives its highest pressure. As the
plunger descends the compensating tanks M, M, become submerged in
the water tank T, and the pressure is reduced uniformly. These tanks
may be of any desired form to vary the pressure in any manner and
extent desired at different parts of the stroke. Two forms of tank are
also

page_text: shewn by the dotted lines o, o, and p, p. Compensation of this kind is
required, for example, in raising a lift bridge or drawbridge, which
requires its greatest power at the commencement of the lift, and a
diminishing power as the bridge is gradually raised.
Figure 6 shews a modification of the arrangement. shewn at Figure 3.
In this case the siphon rises and falls with the compensating tank M,
and the tank T is formed by a hollow central column. This arrange-
ment can also be adapted to vary the load on the hydraulic press at
The
different parts of its stroke in any manner that may be desired.
accumulator shewn in this Figure is also formed with several plungers
combined into a group, so that when it is desirable to cause several rams
to ascend synchronously through equal distances, as in the case of
lifting the two ends of a bridge, or a canal lift or gun platform, the
several rams employed may be supplied with water under pressure from
separate plungers, and all the rams be thereby caused to ascend through
uniform distances.
Plan views of the accumulator are shewn at Figures 7 and 8, the view
shewn at Figure 6 being a vertical section. In all three Figures a, b, c,
d, e, and f, are the six rams and plungers of the accumulator.
To illustrate the working of such an accumulator we have shewn at
Figure 9 a bridge supported by 4 hydraulic presses, one in each of the
towers, as shewn by dotted lines. 4 of the plungers a, b, c, d, are con-
nected respectively by pipes with 4 hydraulic presses at the corners of
the bridges, and the accumulators are so loaded as to descend and to
raise the bridge when the weight rests on these 4 plungers only. e and f
are used for lowering the bridge, and whenever they are placed in
connection with the other four plungers the accumulator rises, and the
On the other
bridge descends as previously described in Figure 4.
hand, when the communication with the two presses c and fis cut off,
the whole weight of the accumulator comes on a, b, c, d, the 4 plungers
descend, and the bridge is raised. Since these 4 plungers are all inde-
pendent, and are connected independently to the 4 presses at the corners
of the bridge, all 4 corners must rise at exactly the same speed and to
the same level. When a vessel desires to pass the bridge is either sub-
merged under water to a sufficient depth to allow the vessel to pass over
it, as shewn at Figure 9, or lifted in the air sufficiently high for the
vessel to pass beneath it. In a similar manner a gun platform may be

page_text: place. When these pins are removed the gland can be turned round
through a portion of a circle, and readily removed to get at the leather.
Figure 12 shews the same arrangement in plan.
At Figure 13 we have shewn more in detail an accumulator con-
structed according to our Invention, applied to the rapid raising and
lowering of heavy guns. O¹ is the press and C the ram supporting the
gun G on a circular platform which is free to revolve. The accumulator
is shewn at A, B, A, W, and it is kept constantly supplied with water
under pressure by a small engine E placed in any convenient position.
The power for traversing the gun is obtained by a small hydraulic press F,
which is connected with the ram by the pipe g, g. By thus employing
a single central ram to raise and lower the gun in combination with a
differential accumulator, such as herein-before described and shewn in
the Drawings, not only is the platform carrying the gun free to rotate
on the point H with its stuffing boxes, but the gun can also be raised
and lowered with but little expenditure of power.
The shot may be lifted to the mouth of the gun by a small press I, I.
To ensure that the gun platform shall maintain a horizontal position
as it is being raised and lowered, parallel levers may be employed in the
manner shewn at Figure 13ª.
A contractor's lift, such as shewn at Figure 14, may also be worked
with an accumulator such as herein-before described.
The accumulator may be such as shewn at Figures 6, 7, and 8. The
press is shewn at A, B, Figure 14, at an angle of 45 degrees. When.
ever C carries a wagon D or other load it may be raised up to a higher
level at E, where the wagon is removed and replaced by an empty
wagon, which descends to a lower level; the power used in raising the
platform and empty wagon being again given back to the accumulator
as it descends. The accumulator is so arranged as to have different
powers. Thus, when all 6 presses are connected with the empty
platform it descends; if two of these presses be cut off, and the weight
of the accumulator be allowed to rest on the remaining 4, the pressure
is sufficient to raise the platform with the ordinary load. If 3 of the
presses d, f, b, Figures 6, 7, & 8, are shut off, and the weight allowed to
remain on the remaining 3, it will raise a wagon with a heavier load;
and if 4 of the presses are shut off, a, b, d, e, and the weight of the
accumulator allowed to rest on the remaining 2 presses, it will be in

page_text: a position to lift the heaviest load, and all these changes may be made
on the instant by opening the valves g, g. A similar hydraulic lift
placed at an angle may be employed for raising and lowering guns, as
shewn at Figures 15 and 16. In the arrangement shewn at Figure 15
the gun is raised and lowered sidewise, whereas in Figure 16 it is raised
and lowered on an incline in a line with the gun.
Having thus described our Invention we would state that we
claim,―
1. The combined arrangement of accumulator and lifting rams for
raising and lowering bridges, canal lifts, and other heavy weights, and
for raising, lowering, and working heavy guns, substantially as herein.
described, whereby the weight to be raised or lowered is permanently
balanced, and the raising or lowering is effected by throwing into action
a supplemental plunger under the accumulator, or by analogous
means.
2. The construction of accumulators with two or more cylinders and
plungers, any or all of which can be caused to sustain the load of the
accumulator, according to the pressure desired, substantially as herein
described.
3. Compensating for the varying immersion of the plungers and
rams by the means substantially as described.
4. Varying the load on the plungers of accumulators at different
parts of the stroke by the means substantially as described and illustrated
at Figures 3, 4, 5, 6, 7, and 8.
5. The employment of an accumulator having two or more cylinders
and plungers to supply water under pressure to two or more presses,
the rams of which are required to be moved synchronously through
stated distances.
6. The means, substantially as herein-before described and illustrated
at Figure 10, for securing the raising and lowering of the bridge or
other weight in a horizontal position.
7. The means of securing the cup leathers of hydraulic apparatus,
substantially as herein described.
8. The means of giving warning when a cup leather of hydraulic
apparatus breaks, substantially as described.

page_text: 9. The combined arrangement for raising and lowering guns,
substantially as herein described and shewn at Figures 15 and 16.
In witness whereof, we, the said Josiah Latimer Clark and John
Standfield, have hereunto set our hands and seals, this Nineteenth
day of January, in year of our Lord One thousand eight
hundred and seventy-four.