IMPROVE- MENTS IN CENTRE CRANES, AND IN OTHER MECHANISM IN WHICH IN LIke MANNER A JIB OR BEAM IS SUPPORTED BY AND MOVEABLE WITH OR ABOUT A CENTRAL STANDARD."
Year: 1880

page_text: LETTERS PATENT to Thomas Wrightson, of the Teesdale Iron Works, near
Stockton on Tees, in the County of Durham, for an Invention of "IMPROVE-
MENTS IN CENTRE CRANES, AND IN OTHER MECHANISM IN WHICH IN LIke
MANNER A JIB OR BEAM IS SUPPORTED BY AND MOVEABLE WITH OR ABOUT
A CENTRAL STANDARD."
PROVISIONAL SPECIFICATION left by the said Thomas Wrightson at the
Office of the Commissioners of Patents on the 5th July 1880.
THOMAS WRIGHTSON, of the Teesdale Iron Works, near Stockton on Tees, in
the County of Durham. "IMPROVEMENTS IN CENTRE CRANES, AND IN OTHER
MECHANISM IN WHICH IN LIKE MANNER A JIB OR BEAM IS SUPPORTED BY AND
MOVEABLE WITH OR ABOUT A CENTRAL STANDARD."
This Invention has for its object improvements in centre cranes, and in other
mechanism in which in like manner a jib or beam is supported by and moveable
with or about a central standard.
In centre cranes as at present constructed it is usual to have an horizontal jib or
beam carried upon the head of the ram of an hydraulic press. The load consisting,
say, of the ladle containing the metal is applied at the outer end of the jib or beam,
and by the injection of water to the cylinder of the press, the ram, the jib, or beam,
and the load are all raised together vertically, and the load can be carried around a
circular course either by the rotation of the ram within the press cylinder, or by
the movement of the jib or beam upon the top of the ram. At present the
dimensions to which these cranes can be made is limited by the very heavy strain
which is experienced when a heavy load is held suspended at the end of a long jib
or arm.
I
According to my Invention I relieve the central standard from this strain. For
this purpose arrange the jib or beam so that it may rock through a small angle.
Near the two ends of the jib or beam I attach to it stay ropes or chains, which I
lead round overhead pulleys suitably carried above the standard, and I bring these
ropes or chains together and connect them with a counterpoise. By this arrange-
ment it results that whilst the jib or beam is as usual under the control of the
central press, and can be raised and lowered by it, and whilst the jib or beam is

page_text: free to turn under the control of the centre standard, nevertheless, this standard is
relieved (either in part or completely) from the tipping strain by means of the stay
ropes or chains, the overhead pulleys, and the counterpoise. The jib or beam by
tipping tightens the stay ropes or chains attached to its more heavily loaded end,
whilst the stays upon the other side become comparatively slack.
A very convenient arrangement for a centre crane is to have a centre post
supported at the bottom upon a footstep containing live rollers, so that it may be
able to turn freely; the post also has a top bearing, it may be in the roof of the
building. The lower part of the post is surrounded by a cylinder having glands at
its ends, so that it can work up and down water tight upon the post. The part of
the post which works in the lower gland is larger than the part which works in the
upper gland, so that when water under heavy pressure is admitted to the cylinder
it rises up upon the post. The water is admitted by an hydraulic pivot to the
lower end of the post, and it issues by an aperture in the side of the post and so
enters the cylinder. At the top of the post there is a frame of pulleys receiving
the stay ropes or chains. The cylinder carries tho jib or beam, which however is
not fixed to it,-but-is-connected--in. such-a-manner that it is free to rock through a
small angle. The counterpoise is of an annular form and surrounds the post.
I make the counterpoise of about one half the weight of the load, it may be more or
less, and I also put a weight, say, one half that of the load at the opposite end of
the jib or beam. In cases where it is inconvenient to employ a suspended
counter-weight, a small hydraulic press may be substituted.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Wrightson in the Great Seal Patent Office on the 5th
January 1881.
THOMAS WRIGHTSON, of the Teesdale Iron Works, near Stockton on Tees, in
the County of Durham. "IMPROVEMENTS IN CENTRE CRANES, AND IN OTHER
MECHANISM IN WHICH IN LIKE MANNER A JIB OR BEAM IS SUPPORTED BY AND
NOVEABLE WITH OR ABOUT A CENTRAL STANDARD."
This Invention has for its object improvements in centre cranes, and in other
mechanism in which in like manner a jib or beam is supported by and moveable
with or about a central standard.
In centre cranes as at present constructed it is usual to have an horizontal jib or
beam carried upon the head of the ram of an hydraulic press. The load consisting,
say, of the ladle containing the metal is applied at the outer end of the jib or beam,
and by the injection of water to the cylinder of the press, the ram, the jib, or beam,
and the load are all raised together vertically, and the load can be carried around a
circular course either by the rotation of the rain within the press cylinder, or by
the movement of the jib or beam upon the top of the ram. At present tho
dimensions to which these cranes can be made is limited by the very heavy strain
which is experienced when a very heavy load is held suspended at the end of a long
jib or arm.
According to my Invention I relieve the central standard from this strain. For
this purpose I arrange the jib or beam so that it may rock through a small angle.
Near the two ends of the jib or beam I attach to it stay ropes or chains, which I
lead round overhead pulleys suitably carried above the standard, and I bring these
ropes or chains together and connect them with a counterpoise. By this arrange-
ment it results that whilst the jib or beam is as usual under the control of the
central press, and can be raised and lowered by it, and whilst the jib or beam is
free to turn under the control of the centre standard, nevertheless, this standard is
relieved (either in part or completely) from the tipping strain by means of the stay
ropes or chains, the overhead pulleys, and the counterpoise. The jib or beam by
tipping tightens the stay ropes or chains attached to its more heavily loaded end,
whilst the stays upon the other side become comparatively slack.
A very convenient arrangement for a centre crane is to have a centre post
supported at the bottom, so that it may be able to turn freely; the post also has a
top bearing, it may be in the roof of the building. The lower part of the post is
surrounded by a cylinder having glands at its ends, so that it can work up and
down watertight upon the post. The part of the post which works in the lower
gland is larger than the part which works in the upper gland, so that when water
under heavy pressure is admitted to the cylinder it rises up upon the post. The
water is admitted by an hydraulic pivot to the lower end of the post, and it issues
by an aperture in the side of the post, and is conveyed from it to the cylinder. At
the top of the post thero is a frame of pulleys receiving the stay ropes or chains.
not fixed to it, but is
The cylinder carries the jib or beam, which however
connected in such a manner that it is free to rock through a small angle. The
counterpoise is of an annular form and surrounds the post. I make the counterpoise
of about one half the weight of the load, it may be more or less; and I also put a
weight, say, one half that of the load at the opposite end of the jib or beam. In
cases where it is inconvenient to employ a suspended counterweight, a small
hydraulic press may be substituted.
In order that my Invention may be fully understood I have shown in the
Drawings hereunto annexed a crane in which my improvements are embodied.
The crane shown is one suitable for raising or lowering a ladle containing melted
metal.

page_text: Figure 1 shows a side elevation partly in section of the crane; Figure 2 shows a
horizontal section of the same, and Figure 3 an end elevation partly in section.
A is the central post, which in order that it may revolve freely I support in a water
pivot. Surrounding part of this post is a cylinder B, which by means of a key is
caused to turn with the post; C is a support attached, say, to a roof for supporting
the top of the post. The cylinder is, as shown, provided at the bottom with a
gland of larger diameter than at the top, so that by admitting water under pressure
to the cylinder, the cylinder can be caused to rise upwards on the post; D is an
arm or jib extending on two opposite sides of the post A; E, E, are pivots at the
bottom of the cylinder on which the arm or jib D can have a slight rocking motion;
F is a frame fixed on the central post and carrying sheaves F'; G is an annular
balance weight surrounding the post and connected by chains, which pass over the
sheaves to the two arms of the jib D; H is a ladle on one arm of the jib, and
capable of containing, when full, say for example, 8 tons of steel; I is a balance
weight on the opposite arm of the jib adjusted so as to balance the cradle when the
ladle contains half its charge, or 4 tons of steel.
The annular balance weight GI make preferably-of such weight as will balance
the whole 4 tons maximum preponderating weight at any time possible on the
cradle, or it might be of greater weight; J shows the lowest position of balanco
weight when cradle is raised; K is the water pivot or bearing supporting the
bottom of the post A; the area of the ram of this pivot is arranged so that nearly
the whole constant weight is balanced by the pressure of water admitted into the
cylinder of the pivot to act upon the rain, the small remainder of the weight
coming on a steel centre; L are radial pipes conveying water to and from
machinery on jib arm; M, position of the same pipes when cradle is raised; N is a
cylinder for moving ladle to and fro along the arm; O, position of valves for
controlling the working of the crane, at which point is also a platform on which a
man-may-stand to work the valves; P is a water passage from lower end of post A,
by which water under pressure can pass to the radial pipes-L, L, and from them by
a pipe Q to the valves at O; R is a pipe for admitting water under pressure to and
for exhaust from the lifting cylinder; S is a pipe for admitting water under
pressure to and for exhaust from the back end of the cylinder, by which the ladle
is moved outwards and inwards along the jib arm; T is a pipe for admitting water
under pressure to and for exhaust from the front end of the same cylinder; U is the
exhaust pipe from the valves leading to radial exhaust pipes V, which conduct the
exhaust to an exhaust passage in the post A, from which it passes out at the top
through a revolving joint at W. The crane may be revolved by bydraulic or other
machinery, or by hand as desired.
In place of using a hydraulic cylinder to move the ladle to and fro along the jib
arm, other suitable mechanical means may be employed for the purpose. In place
also of the valves for controlling the lifting and lowering of the arm or jib of the
crane being mounted upon this arm, they might be at any spot outside the crane,
and the water passage from the valves to the lifting cylinder be carried up through
the post or standard.
Figure 4 shows how the construction of the lower end of the crane post and its
bearing may be modified when the valves are thus placed outside the crane; K is
the hydraulic bearing which supports the lower end of the post A.
In the middle of the packing which forms a watertight joint at the top of this
bearing is a ring X with a groove or channel around its inner circumference. In
the hollow post are holes by which water may pass from the ring to the interior of
the post. In the post is also another hole by which water may pass from the post
into the cylinder B; Y is a pipe by which water under pressure may be allowed to
pass into or to escape from the hollow of the ring X, and so to pass into or escape
from the cylinder B, so as to raise it or allow it to descend.
I have not thought it necessary to show the valves used for admitting water to
and allowing it to escape from the pipe Y, as they may be of any ordinary
construction.

page_text: If, when this arrangement is adopted, an hydraulic cylinder N is also used for
moving the ladle to and fro along the jib arm, this cylinder may be supplied at one
or other end as required with water under pressure from the lifting cylinder B,
and the valves for controlling the supply of water to the ends of the cylinder N,
and the exhaust of water from them may be worked by levers at O, as in the
arrangement shown at Figure 1, or the ladle may be moved to and fro by other
suitable appliances.
In place of water power being used to raise and lower the jib arm on the post,
other mechanical means might be used to effect this object.
Having thus described my Invention and the manner of performing the same,
I would state that I claim,-
First. The construction of centro cranes and other mechanism in which a jib or
beam is supported by and moveable with or about a central standard, with the jib
or beam projecting on two opposite sides of the central standard, and capable of
rocking upon pivots at the standard, and connected on both sides of the standard
by chains passing over pulleys on the standard, or otherwise to a balance weight,
which can rise or fall, or to a hydraulic press or equivalent therefor, substantially as
described.
Second. The construction of centro cranes with the jib arm projecting on two
opposite sides of the central standard, and capable of rocking upon horizontal pivots
at the standard, and with a means of carrying the load to be moved on one arm,
and a counterbalance weight of about one half the load to be moved on the other
arm, and with the two ends of the arm connected by chains passing over pulleys on
the standard or otherwise to a counterbalance weight which can rise or fall, or to a
hydraulic press, or equivalent therefor, substantially as described.
Third. The construction of centre cranes, substantially as hereinbeforo described
and illustrated in the Drawing annexed.
In witness whereof, I, the said Thomas Wrightson, have hereunto set my hand
and seal, this Thirty-first day of December, in the year of our Lord One
thousand eight hundred and eighty.