MENTS IN HYDRAULIC CRANES AND APPARATUS BY WHICH WATER UNDER
Year: 1881

page_text: "
LETTERS PATENT to Frederick William Walker, of the Firm of Tannett and
IMPROVE-
Walker, of Leeds, in the County of York, for an Invention of
MENTS IN HYDRAULIC CRANES AND APPARATUS BY WHICH WATER UNDER
PROVISIONAL SPECIFICATION left by the said Frederick William Walker
at the Office of the Commissioners of Patents on the 10th February 1881.
FREDERICK WILLIAM WALKER, of the Firm of Tannett and Walker, of Leeds,
in the County of York. "IMPROVEMENTS IN HYDRAULIC CRANES AND APPARATUS
BY WHICH WATER UNDER PRESSURE MAY BE SUPPLIED TO THE SAME."
This Invention has for its object improvements in hydraulic cranes and apparatus
by which water under pressure may be supplied to the same.
For the purpose of varying the power of hydraulic cranes I arrange the crane
chains in such a manner that the same amount of lift can be obtained by a greater
or a lesser movement of the ram.
When the load to be lifted is light the crane is so set that the greater length
of chain is taken up by the rise of the ram; but when the load is greater than
the crane can raise in this manner, then the connections of the chain are altered so
as to cause the lesser length to be taken up by the rise of the ram.
In a jib crane the load is suspended by a single chain passing over the pulley
upon the jib, and then attached to a doubled or endless chain. The parts of this
chain pass down and around a pair of guide pulleys, thence over the pulleys on the
head of the ram, and the bite or loop of the doubled chain is passed around a
stationary pulley upon the crane post. In connection with one of the guido pulleys
(or near the position of these pulleys) I provide a locking arrangement by which
one part of the doubled chain can be held fast or liberated at pleasure. The chain
is thus locked when working with small loads. The rise of the ram is then
operative to lift the load, by means of one part only of the doubled chain, and the
other part as the ram rises becomes slack. Thus when the chain runs free tho
537

page_text: greater weight is lifted with the full ram stroke, and when fastened the lesser
weight is lifted the same height with half the ram stroke.
In cranes in which it is required to rack the load when raised to or from the
centre, the lifting chain also is endless; it passes around a pulley on the jib
end, and both sides of the chain going to the hook block are drawn up at the same
time.
In ingot cranes, or cranes in which an hydraulic cylinder forms the crane post,
and the ram carries a radial beam from which the load is suspended, I prolong the
ram with a reduced diameter through the bottom of the hydraulic cylinder, out of
which it passes by a stuffing box.
The cylinder is in constant connection with the accumulator or supply of pressure
water, and the diameters of the ram are so proportioned that the hydraulic
pressure in the cylinder nearly balances the dead weight of the crane.
On either side of the centre cylinder I provide other smaller cylinders and rams
to and from which the water is directed by valves to move the crane.
Either one
or both of the side cylinders can be used at a time, according as the load to be
raised is light or heavy.
In order to admit water under pressure to the cylinders of hydraulic cranes, and
to draw the water off therefrom, I employ a double slide valve. One of the cavities
in this valve covers a supply port, and the other an exhaust or outlet port. By
the movement of the valve either of these cavities can also be brought over a third
port leading to the cylinder. This slide valve is enclosed in the usual way in a
valve chest, but this in place of being in direct communication with the source as
at present is supplied with water at a lower pressure, such that acting upon the
whole area of the valve it is sufficient to keep the valve to the valve face, notwith-
standing the pressure of the supply acting in one only of the cavities of the valve.
A reducing valve can be employed to admit water to the valve chest at the required
reduced pressure. Valves thus arranged can be opened and closed with much
greater ease than the valves at present in use with hydraulic cranes, and are also
applicable to control the fluid under pressure for other purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick William Walker in the Great Seal Patent Office on the
10th August 1881.
FREDERICK WILLIAM WALKER, of the Firm of Tannett and Walker, of Leeds,
in the County of York. "IMPROVEMENTS IN HYDRAULIC CRANES AND APPARATUS
BY WHICH WATER UNDER PRESSURE MAY BE SUPPLIED TO THE SAME."
This Invention has for its object improvements in hydraulic cranes and apparatus
by which water under pressure may be supplied to the same.
the ram.
For the purpose of varying the power of hydraulic cranes, I arrange the crane
chains in such a manner that the same amount of lift, can be obtained by a greater
or a lesser movement of the ram. When the load to be lifted is light, the crane is
so set that the greater length of chain is taken up by the rise of the ram, but when
the load is greater than the crane can raise in this manner, then the connections of
the chain are altered, so as to cause the lesser length to be taken up by the rise of
In a jib crane the load is suspended by a single chain passing over the
pulley upon the jib and then attached to a doubled or endless chain. The parts of
this chain pass down and around a pair of guide pulleys, thence over the pulleys
on the head of the ram, and the bite or loop of the doubled chain is passed around
a stationary pulley upon the crane post. In connection with one of the guide
pulleys (or near the position of these pulleys) I provide a locking arrangement, by
which one part of the doubled chain can be held fast or liberated at pressure. The
chain is thus locked when working with small loads. The rise of the ram is then
operative to lift the load by means of one part only of the doubled chain, and the
other part as the ram rises becomes slack. Thus when the chain runs free the
greater weight is lifted with the full ram stroke, and when fastened the lesser weight
is lifted the same height with half the ram stroke.
In cranes in which it is required to rack the load when raised to or from the
centre, the lifting chain also is endless; it passes around a pulley on the jib end,
and both sides of the chain going to the hook block are drawn up at the same
time.
In ingot cranes, or cranes in which an bydraulic cylinder forms the crane post,
and the ram carries a radial beam from which the load is suspended, I prolong the
ram with a reduced diameter through the bottom of the hydraulic cylinder, out of
which it passes by a stuffing box. The cylinder is in constant connection with the
accumulator or supply of pressure water, and the diameters of the rain are so
proportioned that the hydraulic pressure in the cylinder nearly balances the dead
weight of the crane. On either side of the centre cylinder I provide other smaller
cylinders and rams to and from which the water is directed by valves to move the
crane. Either one or both of the side cylinders can be used at a time according as
the load to be raised is light or heavy.
In order to admit water under pressure to the cylinders of hydraulic cranes, and
to draw the water off therefrom, I employ a double slide valve. One of the cavities
in this valve covers a supply port, and the other an exhaust or outlet port. By the
movement of the valve either of these cavities can also be brought over a third
port leading to the cylinder. This slide valve is enclosed in the usual way in a
valve chest, but this in place of being in direct communication with the source as
at present is supplied with water at a lower pressure, such that acting upon the
whole area of the valve it is sufficient to keep the valve to the valve face, notwith-
standing the pressure of the supply acting in one only of the cavities of the valve.
A reducing valve can be employed to admit water to the valve chest at the
required reduced pressure. Valves thus arranged can be opened and closed with

page_text: much greater ease than the valves at present in use with hydraulic cranes, and are
also applicable to control the fluid under pressure for other purposes.
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 and Figure 2 is a back elevation of a double powered
hydraulic crane, in which the variation of the power is obtained by locking or
freeing the crane in accordance with my Invention. The crane here represented
is a racking crane in which 'the load when raised can be moved to and from the
centre. a, a, is the jib or arm of the crane; it has its pivots at a¹, a', on which it
is able to turn freely, as is usual in cranes of this class; b is the hydraulic cylinder;
it is carried upon the part a, and provision is made for admitting to it water under
pressure (from an accumulator or otherwise) when the load is to be raised and for
allowing the water to escape when the load is to be lowered; c is the ram; it carries
upon its head a pair of pulleys c¹, c¹, and there is another pulley b¹ on a stud axis
projecting from the side of the cylinder b. Two endless or doubled chains are
employed; one marked d passes beneath the pulley b', and over the two pulleys c¹, c¹,
whence it descends and passes beneath the pulleys a², ax, on the swinging jib a. Near
the point d the doubled or endless chain & is attached to another endless or doubled
chain e. The chain e passes over the pulleys a³, a³, and thence one part passes direct
to the pulley f¹ of the monkeyf, whilst the other passes over the pulley a* at the outer
end of the jib or arm u and thence to the pulley f2 on the monkey. The monkey
is supported upon wheels f³ running upon the top of the jib or arm a, and as usual
the monkey can be traversed along the jib or arm a without altering the distance
of the load from the ground, the load being carried by a block hook suspended in
the bite of the chain between the pulleys fi and f2 on the monkey. By means of
a bolt or like contrivance one limb of the doubled chain d can be locked fast when
desired upon or in the neighbourhood of the pulley a. When it is so locked the
effect of the rise of the ram is to throw slack the portion of chain between a² and d',
whilst the length of chain drawn over the pulley a²x becomes equal to four times
the rise of the ram, the lift of the load at the same time being twice the rise of
the ram.
On the other hand, when the pulley u² rotates none of the chain becomes
slack, and the lift of the load is equal to the rise of the ram. In cases where
racking movement is not required a single chain is attached to the chain & at d¹,
and may be led over a pulley or pulleys upon the jib to the load; the rise of the
load is then either twice or four times the rise of the ram, as the case may be.
Figure 3 is a vertical section, and Figure 4 is a plan of an ingot crane constructed
according to my Invention.
a is an hydraulic cylinder and b is a ram contained within it, and passing through
stuffing boxes at each of its ends; c is a beam supported on a pivot at the top of
the ram b, and also controlled by rollers b¹, b¹, mounted upon the side of the ram;
d is a carriage capable of traversing along the bean c, and by a chain and hook or
like means the load to be lifted and conveyed is connected with the carriage d; cis
a counterpoise at the other end of the beam c, equal about to the average load of
the crane.
The lower end of the ram b is smaller than the upper end, and the cylinder a is
always in connection with the accumulator or store of pressure-water. This being
so, and the pressure and the areas being suitably adjusted, when there is no load
suspended from the carriage d, the ram b is ready to rise on a very small lifting
force being applied to it; f and f' are two small hydraulic cylinders, one on either
side of the cylinder a, and they may be cast of a piece with it; the casting is firmly
bolted to a foundation. The small hydraulic cylinders contain rams g, g¹, passing
out at the top through stuffing boxes, and made fast to a cross head 62, on the
ram b. The pressure water is admitted to one or to both of these cylinders ƒ ƒ³,
when a lift is required by opening a suitable valve or valves, and to lower the
water is drawn out from these cylinders. Thus the great waste of pressure water

page_text: which occurs generally in the use of this description of crane is avoided, and the
expenditure need be little in excess of what is equivalent to the load suspended
from the crane.
My improved valve and arrangements for the supply of water under pressure
are shown by the Figures 5, 6, and 7.
Figure 5 is a vertical section; Figure 6 is a transverse section; Figure 7 is a plan
of the valve face.
a is the passage bringing the pressure water from the accumulator; b is the
passage from beneath the valve to and from the cylinder; and c is the exhaust or
outlet passage; d is the valve proper, it is double, and as it stands in Figure 5 it
closes all the ports; e is the valve rod, it passes through stuffing boxes at the ends
of the valve chamber f, when by means of the rod e the valve is shifted to the right
the cylinder is open to the exhaust or outlet, as is required in lowering. When
on the contrary the valve is moved to the left, the cylinder is put into commu-
nication with the pressure passage a, and water enters it from the accumulator, as
is required for raising a load; g is the passage leading pressure water from the
passage a into the chamber f, to maintain a suitable pressure therein, such that
acting over the whole area of the valve d, it may be somewhat more than
equivalent to the high pressure operating within one cavity only of the valve. is
a differential valve in the passage g, and opening into the chamber f. The stem of
the valve passes through a stuffing box to the outside, and thus the effective area
of the valve where it is exposed to the full pressure in the passage g, is reduced to
something considerably less than the effective area of the valve within the
chamber Consequently the valve h closes when the pressure in the chamber fis
much under that in the passage g. A suitable proportion is maintained between
the pressures by giving the proper dimensions to the stem of the valve h; i is a
safety valve leading back to the accumulator.
Having thus described the nature of my said Invention, and the manner of
performing the same I would have it understood that I claim,—
First. The means herein described for varying the power of an hydraulic crane
by the use of a doubled chain, of which one limb can at pleasure be locked fast, so
that when the doubled chain is taken up by the ram it operates on the load either
by one limb only or by both limbs, as the case may be.
Second. The method of constructing ingot cranes, substantially as described, so
that the beam of the crane and the rising parts are at all times (when the crane is
in use) nearly water borne by pressure water, acting constantly within a cylinder.
beneath a supporting ram, the load being lifted and lowered by supplying and
withdrawing pressure water to and from another cylinder or cylinders, to act
beneath a lifting ram or rams contained therein.
Third. My improved pressure water admission and draw off valve, substantially
as described, in which the valve proper is held to its seat notwithstanding the full
pressure beneath it operative on a part of the area by a suitably reduced pressure
inaintained within the valve chamber and operative on the larger arca at the back
of the valve.
In witness whereof, I, the said Frederick William Walker, have hereunto set
my hand and seal, this Eighth day of August, in the year of our Lord One