IMPROVEMENTS IN HYDRAULIC CRANES, CAPSTAN ENGINES, AND OTHER HYDRAULIC MACHINERY
Year: 1877

page_text: LETTERS PATENT to Frederic Eliot Duckham, of Millwall, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN HYDRAULIC CRANES,
CAPSTAN ENGINES, AND OTHER HYDRAULIC MACHINERY."
Sealed the 22nd June 1877, and dated the 27th April 1877.
PROVISIONAL SPECIFICATION left by the said Frederic Eliot Duckham at
the Office of the Commissioners of Patents on the 27th April 1877.
FREDERIC ELIOT DUCKHAM, of Milwall, in the County of Middlesex.
MENTS
" IMPROVE-
IN HYDRAULIC CRANES, CAPSTAN ENGINES, AND OTHER HYDRAULIC
MACHINERY."
My Invention relates to improvements in hydraulic cranes and hoists, hydraulic
engines for capstans, winches, and other hydraulic machinery, and its object is to
regulate automatically the supply of water to the cylinders in proportion to the
work to be done. I am aware that machinery of this kind has been provided with
a means of regulation, but its action has not generally been automatic but de-
pendent upon an attendant for its efficiency, which may be altogether neutralized
by inattention or want of judgment, so that as much power is consumed in working
the machinery when unloaded or with a light load as when fully loaded.
As applied to hydraulic cranes and hoists my Invention consists in attaching that
end of the hoisting chain which is usually made fast to the lifting cylinder to a
lever which is loaded with a spring or springs, or with two or more weights acting
in opposition to the strain on the lifting chain, and so arranged as to come into
operation successively as the said strain increases, and greater power is required to
perform the work. I will suppose the crane to be an ordinary three cylinder crane,
and the power developed to be regulated by admitting the water to one or more of
the cylinders. At any convenient point I place a valve capable of controlling the
admission of water to three cylinders, and I connect the spindle of the said valve
with the lever above mentioned, so that any movement of the said lever shall
produce a corresponding movement of the valve. This valve may be a slide moving
over two ports, communicating the one with the two outer cylinders and the other
with the iniddle cylinder.

page_text: The admission of hydraulic power to the valve chest is governed by the ordinary
manual working valve, at which the water is allowed to escape when the action
of the machinery is reversed, as in lowering goods. When the slide valve covers
the one port water is admitted to the middle cylinder only, and one-third only of
the full power of the machine is developed. When the strain on the hoisting chain
reaches nearly that amount the load on the lever is overcome and the lever is
moved, thereby shifting the slide valve so as to uncover the other port and cover
the first one.
Water is now admitted to two of the cylinders; but should greater
power be necessary to do the work, the slide valve will be still further shifted, so
as to uncover both ports and admit water to all the cylinders.
It will be obvious that the lever and the valve may be otherwise arranged, and
more than one valve may be employed if preferred.
When the rams of the three cylinders are attached to a common cross head, or
otherwise connected so as to necessarily move together, whether in work or not,
it is necessary to prevent the indrawing of air or the forming of a partial vacuum
in the cylinders not in use. This I effect by connecting them with a waste water
tank or other reservoir, so that water not under pressure may be drawn into these
cylinders when their rams are drawn out, the return of the water being prevented
by suitable clack valves.
When the machine is used for lowering purposes the reverso action takes place,
the water is allowed to escape at the manual valve, the water from all three
cylinders being permitted to pass thereto by the opening of self-acting valves in
the slide valve chest.
In applying my Invention to the hydraulic engines of capstans and other winding
machinery, in which the reciprocating motion of the rams or pistons is converted
into rotary motion of the crank shaft, I employ a different arrangement to render
the power developed in the engine proportionate to the work to be done. In this
case, instead of the number of cylinders in work being varied in order to regulate
the power, the length of stroke of the rams or pistons is reduced and the power is
applied to the crank shaft through a crank of smaller radius when the full power
is not required, whereby less water is consumed at each stroke and the speed of the
engine is increased. This is effected automatically by the following arrangement:-
Each ram or piston is made by a link motion and connecting rods to work two
cranks of different radius, the larger crank being connected with one end of the
link and the smaller crank with the other end, so that by shifting the link so as
to bring the slide on the rams or piston rod to one end or the other of the link in
the ordinary way, the ram or piston will work the larger or smaller crank, or both
when in an intermediate position, as the case may be, and the stroke will be corrc-
spondingly altered. The position of the link motion is governed by a lever
actuated in the one direction by a special ram, subject at all times to the same
hydraulic pressure as that in or near the working cylinders, and which pressure
becomes reduced almost in proportion to the resistance met with by the working
ram or piston in making its stroke. The lever is actuated in the reverse direction
by a spring (or it might be a series of weights acting in succession, as before
described), which opposes the pressure of the ram above mentioned.
When working with a light load the power of the spring preponderates, and
overcoming the ram moves the lever and through it the link, so as to gradually
reduce the stroke of the working ram or piston and cause its power to be applied
through the smaller crank. As more power is required to perform the work the
pressure on the ram increases, and overcoming the spring moves the link the other
way so as to lengthen the stroke and increase the application of the power through
the larger crank, thereby automatically regulating the power consumed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed.
by the said Frederic Eliot Duckham in the Great Seal Patent Office on the
27th October 1877.
"
FREDERIC ELIOT DUCKHAM, of Millwall, in the County of Middlesex. IMPROVE-
MENTS IN HYDRAULIC CRANES, CAPSTAN ENGINES, AND OTHER HYDRAULIC
MACHINERY."
My Invention relates to improvements in hydraulic cranes and hoists, hydraulic
ongines for capstans, winches, and other variable power hydraulic machinery, and
its object is to regulate automatically the supply of water to the cylinders in pro-
portion to the work being done. I am aware that machinery of this kind has been
provided with a means of regulation, not generally automatic however in its action,
but dependent for its efficiency upon an attendant, who by inattention or want of
judgment may neglect or fail to properly proportion the supply of water to the
work to be done, so that as much or nearly as much water is used, and conse-
quently as much power is expended in working the machinery when unloaded or
only partially loaded as when fully loaded.
As applied to hydraulic cranes and hoists my Invention consists in attaching
that end of the hoisting chain which is usually made fast to the lifting cylinder
to a lever loaded with a spring or springs, or with one or more weights acting in
opposition to the strain on the lifting chain, and so arranged as to come into
operation gradually or successively as the said strain increases and greater power
is required to perform the work, the said lever being connected to and operating
a valve or valves by which the admission of water to the cylinders is controlled.
In order that my Invention may be more readily understood I will proceed to
describe it in detail, with reference to the accompanying Drawings, and I will
suppose the crane or hoist to be of the ordinary three cylinder type, represented in
side elevation in Figure 1 and in plan in Figure 2. In this case the power
developed is regulated by admitting the water to one, two, or more of the cylinders.
At any convenient point I place a valve A, of any suitable construction, capable of
controlling the admission of water to the cylinders as above mentioned, and I
connect the spindle a of the said valve with the long arm of a lever B, so that any
movement of the said lever shall produce a corresponding movement of the valve. This
valve may be a slide moving over two ports (as shown on a larger scale in vertical
section in Figure 3, and in face view with the valve removed in Figure 4), com-
municating the onec by pipe ol with the two outer cylinders C, C¹, and the other d
by pipe d with the middle cylinder D.
The
The admisson of hydraulic power to the valve chest by the port e and pipe e' is
governed by the ordinary manual working valve, at which the water is allowed to
escape when the action of the machinery is reversed, as in lowering goods.
lever B is fulcrumed at 6 on one of the cylinders or other suitable support, and its
long arm is permanently loaded by a weight W properly adjusted in relation to the
power of a single cylinder of the crane or hoist. To the said arm is also attached
a pendant rod F, having a head or stop f hanging through another weight W₁,
which in the position shown in the Drawing is resting on the ground or other
support and does not come into action until the lever rises. Instead of a rod Fa
chain might be used. To the short arm of the lever B the end of the hoisting
chain G is attached in such way that the tension of the chain tends to move the
lever in opposition to the weights W, W₁. When the slide valve covers the one
port c water is by the port d admitted to the middle cylinder D only, and one-third
only of the full power of the machine is developed. When the strain on the hoist-
ing chain reaches nearly that amount the load W is overcome, and the lever raised
until arrested by the stop f coming in contact with the weight W, whereby the
slide valve is shifted so as to uncover the other port c and cover the first one d.
Water is now admitted to the two cylinders C, C₁, and two-thirds of the power of
the machine is developed. Should greater power be necessary to do the work the

page_text: load W¹ is similarly overcome and the lever still further raised, until the slide
valve is moved sufficiently to uncover both ports c, d, and thus admit water to all
the cylinders. The lever B is guided by the uprights H, which are fixed rigidly
in the machinery pit, and the upward movement of the lever is limited by a
stop I.
When the machine is used for lowering purposes the reverse action takes place,
the water is allowed to escape at the manual valve, the water from all three
cylinders being permitted to pass thereto by the opening of self-acting valves g, G,
in the slide valve chest.
When the rams of the three cylinders are attached to a common cross head, or
otherwise connected, so as to necessarily move together, whether all are in work or
not, it is requisite to prevent the indrawing of air or the forming of a partial
vacuum in the cylinders not under pressure. With this object I connect them with
a waste water tank or other reservoir, so that water not under pressure may be
drawn into these cylinders when their rams are drawn out, the return of water to
such reservoir being prevented by suitable clack valves.
It will be obvious that springs may be substituted for the weights W, W', and
that the lever B and valve A may be otherwise arranged, and more than one valve
may be employed, if preferred, and that a similar lever and valve or valves of other
suitable design may be used to control the working of a single cylinder with
differential ram or other variable power hydraulic machinery. In the case of a
single cylinder with two concentric rams (the inner one solid and the outer one
aunular) the power is usually regulated by locking the annular ram by a mechanical
contrivance instead of by a variable admission of water, and in this case the
weighted lever would be applied to actuate directly this mechanical contrivance, no
valve being used.
In applying my Invention to the hydraulic engines of capstans and other winding
machinery, in which the reciprocating motion of the rams or pistons is converted
into rotary motion of the crank shaft, I employ a different arrangement (of which
Figures 5 and 6 represent an example) to render the expenditure of power in the
engine proportionate to the work being done. In this case, instead of the number
of cylinders in work being varied in order to regulate the power, the length of
stroke of the rams or pistons is reduced and the power is applied to the crank shaft
through a crank of smaller radius, or through a shorter lever when the full power
is not required, whereby less water is consumed at each stroke and the speed of the
engine is increased. This is effected automatically by the following arrangement
in the example shown:-Each ram or piston K is made by a link motion L, and
connecting rods M, M¹, to work two cranks of different radius N, N¹, the larger
crank N being connected with one end of the link and the smaller crank N¹ with
the other end, so that by shifting the link to bring the slide on the ram or piston
rod to one end or other of the link in the ordinary way, the ram or piston will
work the larger or smaller crank, as the case may be (or both when in an inter-
mediate position), and its stroke will be correspondingly altered. The position of
the several link motions, relatively to their rams or piston rods, is governed by
lever arms P, connected to the links by rods P¹, and fixed on a common shaft S,
and actuated in the one direction by a special ram Q, Figure 6, subject at all times
to the same hydraulic pressure as that in or near the working cylinders, which
pressure becomes reduced almost in proportion to the resistance met with by the
working ram or piston in making its stroke. There are usually three working rams
or pistons K and one regulating ram Q to each capstan engine, but there may be
only two working pistons if desired. The ram Q actuates the shaft S through a
lever arm R, fixed on the shaft S, and passing at its free end through a slot in the
ram Q; the latter is mounted on the same bed side by side with the working
rams K. The lever R is actuated in the reverse direction by a spring T (or it might
be a series of weights acting in succession, as before described), which opposes the
pressure of the ram Q.
When working with a light load the power of the spring preponderates and,

page_text: overcoming the ram, moves the links so as to gradually reduce the stroke of the
working rams or pistons and cause their power to be applied through the smaller
cranks. As more power is required to perform the work the pressure on the regu-
lating ram Q increases, and, overcoming the spring or weights, moves the link the
other way, so as to lengthen the stroke and increase the application of the power
through the larger crank, thereby automatically regulating the power expended.
Instead, however, of the links being movable and the rams stationary, the rams K
may be made to work on trunnions and the links L to work as simple levers,
oscillating on a stationary pivot at one end 0¹, and one crank N to connect rod M
only be employed, the arm P being in this case connected by links P¹ with the
rams. Similar action of the regulating ram would produce similar, results as
regards the variation of the length of stroke of the working rains, by the said rams
being moved up or down the links or levers instead of the links being moved past
the rams, as before described. It will be obvious that the levors L may be
variously arranged to produce the same result.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patents is,-
Firstly. The automatic regulation of the power of hydraulic cranes or hoists by
applying the weight on the hoisting chain itself to control the admission of water
to the ram cylinders, or to actuate mechanical contrivances used to control the
rams, as the case may be, substantially as shown and described.
Secondly. In bydraulic cranes or hoists the employment of a loaded lever, sub-
stantially as shown and described, as a medium for actuating by the strain on the
hoisting chain a valve or valves controlling the admission of water to the cylinders,
or a mechanical device controlling the working of the rams, as and for the purpose
specified.
Thirdly. The automatic regulation of the power of hydraulic working engines, by
applying the variable pressure of the water at a point near the working rams to
operate machinery, whereby the stroke of the working rams or pistons is pro-
portioned to the work being done by the machine, substantially as herein
specified.
Fourthly. The combination with the rams or pistons of hydraulic winding
engines of link motions connected at their opposite ends to cranks of different
radius, and adjusted in relation to the rams or pistons by a hydraulic cylinder,
subject to the same pressure as the working cylinders, acting in opposition to
springs or weights, substantially as shown and described.
Fifthly. The combination with the rams or pistons of hydraulic winding engines
of levers, connected each to a single crank, the length of leverage and consequently
the stroke of the rams or pistons being regulated by a special ram, as specified.
In witness whereof, I, the said Frederic Eliot Duckham, have hereunto set
my hand and seal, this Twenty-third day of October, in the year of our
Lord One thousand eight hundred and seventy-seven.
FRED. E. DUCKHAM. (L.S.)