BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates to a crane, and more
particularly, to a ladle crane used to transport a ladle.
2. DESCRIPTION OF RELATED ART
Conventionally, in iron and steel making facilities,
molten steel is charged into a ladle and transported by a
ladle crane together with a ladle. For example, molten steel
discharged from a blast furnace is charged into the ladle,
transported to a converter and the like by a ladle crane, and
charged into the converter.
The ladle crane transports the ladle in a state it is
hoisted up by a main hoist apparatus, and the molten steel is
poured from the ladle into the converter and the like by
tilting the ladle by lifting the lower portion thereof with an
auxiliary hoist apparatus (refer to, for example, Japanese
Unexamined Patent Application, Publication No. 11-268881).
In the conventional ladle crane, motor controllers for
controlling motors for driving the main hoist apparatus and

the like are disposed in the space of a girder of the ladle
crane.
The motor controllers control currents and voltages
supplied to the motors and includes various devices such as a
power control semiconductor device and the like for
controlling the currents and the like. In general, the life
of these devices is shorter than that of a ladle crane main
body, and the period of upgrade of them is also shorter than
that of the ladle crane main body.
To replace a failed device whose end of life has been
reached, the failed device itself is replaced or the failed
device is replaced together with the motor controller. When
production of a device is finished due to upgrade and the
like, since a control circuit of the current and the like must
be replaced with a control circuit corresponding to a new
device after upgrade, the device must be replaced together
with a motor controller.
However, since the motor controller is disposed in the
narrow space in the girder, a problem arises in that
replacement of the device itself is troublesome and time
consuming. In particular, when a device fails because the end
of its life has been reached, since a plurality of devices
continuously fail during a relatively short period of time,
there is a problem in that replacement of the devices
themselves is troublesome and time consuming. When motor

controllers are replaced, since the motor controllers to be
replaced are disposed in the girder, replacement of them is
troublesome and time consuming as well as since the motor
controllers must be carried in and out from the girder, a
problem arises in that replacement of them is difficult.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention, which was made to
solve the above problems is, to provide a crane capable easily
replacing and updating a power control semiconductor device
and the like.
To achieve the above object, the present invention
provides the following means.
The present invention provides a ladle crane including a
crane main body, motors, motor controllers for controlling the
output of the motors by controlling power to be supplied to
the motors, and an electric room in which the motor
controllers are disposed, wherein the electric room is
detachably mounted on the crane main body.
According to the present invention, since the motor
controllers are intensively disposed in the electric room
mounted on the crane main body, devices used for power control
such as power control semiconductor devices and the like can
be easily replaced and updated. Since the electric room is
disposed independently of the crane main body, the space in

electric room can be more increased as compared with a case in
which the motor controllers are disposed in the space of the
crane main body. Accordingly, a job for replacing and
updating the above devices in the electric room can be easily
carried out. Since a worker can easily enter into and exit
from the electric room, he or she can easily replace and
update the above devices.
Since the electric room is detachably mounted in the
crane main body, the motor controllers themselves can be
replaced in a state that the electric room is dismounted from
the crane main body. Since the electric room dismounted from
the crane main body can be moved to a place more suitable to
replace the motor controllers, they can be easily replaced.
Exemplified as the place more suitable to replace the motor
controllers is located lower than a high place where the crane
main body is disposed and containing a less amount of dusts
and the like.
In particular, when a motor is an inverter-controlled
motor and a motor controller is an inverter apparatus, since
intervals at which the inverter apparatus is upgraded are
shorter than a period of time during which the crane is used,
it is preferable to easily replace the motor controller in
conformity with the upgrade.
In the crane of the present invention, since the devices
of the motor controllers and the motor controllers themselves

can be easily replaced, the crane is preferable when inverter
apparatuses having frequently upgraded devices and the like
are used as motor controllers.
Otherwise, a time necessary to replace the motor
controllers and to replace and update the above devices can be
reduced by preparing an electric room different from the
electric room to be dismounted from the crane main body and
replacing the latter electric room with the former electric
room. The devices and the motor controllers which require
replacement and the like can be subjected to the replacement
and the like with a sufficient time after the electric room is
dismounted from the crane main body.
The motor controllers are intensively disposed in the
electric room and the electric room is mounted on the crane
main body, by which the number of parts used to install the
motor controllers can be reduced as compared with a case in
which the motor controllers are directly disposed in the crane
main body. The inside of the electric room can be arranged to
have a structure suitable to dispose the motor controllers
therein. Accordingly, the number of the parts used to install
the motor controllers can be reduced as compared with the case
in which they are directly disposed to the crane main body.
Since wirings are made collectively from the electric
room to the crane main body, a labor hour necessary to wiring
work can be reduced as compared with a case in which wirings

are individually made to the motor controllers. Since the
electric room is solely used to dispose the motor controllers
therein, wirings from the motor controllers to the outside of
the electric room can be previously made in the electric room.
Accordingly, a labor hour necessary to wiring work for
replacement and the like of the devices of the motor
controllers and replacement of the motor controllers
themselves can be easily reduced. When the electric room is
mounted on and dismounted from the crane main body, a labor
hour necessary to wiring work can be reduced by bundling
wirings between the electric room and the crane main body to a
single wiring.
In the present invention, it is preferable that the crane
main body include a girder traveling along traveling beams, a
trolley traveling along the girder, and a hoist apparatus
disposed to the trolley for hoisting up and down a hoisting
load, wherein the motors are used to at least one of traveling
of the girder, traveling of the trolley, and hoisting up and
down of the hoisting load carried out by the hoist apparatus,
and the electric room is detachably mounted on the girder.
With the above arrangement, since the electric room, in
which the motor controllers used to at least one of traveling
of the girder and the trolley and hoisting of the hoisting
load are disposed, is detachably mounted on the girder, the
motor controllers and the devices used in them can be easily

replaced. Since the electric room can be easily carried in
and carried out from the girder, the electric room can be
easily mounted and dismounted by disposing it to the girder.
Since the motors are used to at least one of traveling of
the girder and the trolley and hoisting of the hoisting load,
power control semiconductor devices and the like are used to
the motor controllers for controlling the motors. Since the
power control semiconductor devices and the like are
periodically upgraded, it is preferable to easily replace the
motor controllers in conformity with upgrade.
In the crane of the present invention, since the devices
of the motor controllers and the motor controllers themselves
can be easily replaced, the crane is preferably used when
inverter apparatuses having frequently upgraded devices and
the like are used as motor controllers.
In the above invention, it is preferable that the
electric room includes fitting portions to be fitted to a
crane for hoisting down the electric room.
With this arrangement, since the fitting portions are
disposed to the electric room, it can be hoisted down by other
crane, thereby the electric room can be easily mounted on and
dismounted from the crane main body.
In particular, in a large crane such as the ladle crane
and the like, since a large capacity is required to the motor
controllers, the weight thereof is increased. Since the

weight of the electric room, in which a plurality sets of the
main hoist inverter apparatuses 59A and the like are disposed,
is increased, when the electric room is mounted on and
dismounted from the crane main body, a crane must be used to
hoist down the electric room. Since the electric room can be
easily hoisted down using the crane because it is provided
with the fitting portions, the electric room can be easily
mounted and dismounted.
In the above arrangement, it is preferable that the
girder includes a support portion disposed thereto so as to
project therefrom to the outside for supporting the electric
room, and the electric room includes coupling portions to be
detachably fixed to the support portion.
With this arrangement, since the electric room is mounted
on the support portion of the girder through the coupling
portions, it can be easily mounted on and dismounted from the
support portion.
Since the support portion is disposed so as to project
from the girder to the outside, when the electric room is
mounted on and dismounted from the support portion, the
electric room is unlike to interfere with crane main body and
the like, thereby a mounting/dismounting job of the electric
room can be easily carried out. The electric room can be
dismounted by separating the coupling portions from the
support portion, whereas it can be mounted by coupling the

mounting/dismounting job of the electric room to be carried
out easily.
In the present invention, it is preferable that the
electric room include a heat insulating portion for preventing
invasion of heat from the outside.
With this arrangement, since the electric room is
provided with the heat insulating portion, invasion of heat
into the electric room from the outside can be prevented,
thereby failure of the motor controllers caused by heat can be
prevented.
When, for example, the ladle containing molten steel is a
hoisting load, it is preferable that the heat insulating
portion 37 is disposed to the lower surface of the electric
room. Invasion of heat radiated from the molten steel can be
prevented by disposing the heat insulating portion as
described above.
In the present invention, it is preferable that the crane
include first motors, a plurality of first motor controllers
disposed in the electric room for controlling the output of
the first motors by controlling the power supplied to the
first motors, a second motor, and a second motor controller
disposed in the electric room for controlling the output of
the second motor by controlling the power supplied to the
second motor, wherein power can be supplied to the second

In the present invention, it is preferable that the crane
include first motors, a plurality of first motor controllers
disposed in the electric room for controlling the output of
the first motors by controlling the power supplied to the
first motors, a second motor, and a second motor controller
disposed in the electric room for controlling the output of
the second motor by controlling the power supplied to the
second motor, wherein power can be supplied to the second
motor from the first motor controllers and stopped thereby and
that the first motor controllers be any of a plurality of
controllers for controlling a plurality of hoist motors of a
main trolley, respectively, and the second motor controller be
a motor controller of a hoist motor of an auxiliary trolley.
With the above arrangement, even if the second motor
controller fails, since the second motor is operated by the a
first motor controller, the electric room can be dismounted
after, for example, the girder is moved to a safe position by
hoisting up a hook.
In particular, even in a state that the molten steel is
contained in the ladle, since the electric room is dismounted
after the molten steel in the ladle is charged into a
converter, a wasteful labor hour can be greatly saved as
compared with a conventional crane as well as parts disposed
in the electric room can be promptly and safely repaired.

According to the crane of the present invention, since
the motor controllers are intensively disposed in the electric
room mounted on the crane main body as well as the electric
room is detachably mounted on the crane main body. As a
result, the present invention can achieve such an advantage
that the motor controllers themselves can be replaced in a
state that the electric room is dismounted from the crane main
body, and the power control semiconductor devices and the like
can be easily replaced and upgraded.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE ACCOMPANYING DRAWINGS
Fig. 1 is a plan view explaining an arrangement of a
ladle crane according to an embodiment of the present
invention;
Fig. 2 is a side elevational view explaining arrangements
of a main girder and a main trolley of Fig. 1;
Fig. 3 is a schematic view explaining an arrangement of
the ladle crane of Fig. 1;
Fig. 4 is a block diagram explaining an arrangement of an
electric circuit of traveling motors of Fig. 3;
Fig. 5 is a cross sectional view explaining arrangements
of the main trolley, an auxiliary trolley, and an electric
room of Fig. 1;
Fig. 6 is a block diagram explaining an arrangement of an
electric circuit in a main hoist apparatus and an auxiliary

hoist apparatus of Fig. 1;
Fig. 7 is a block diagram explaining an arrangement of an
electric circuit in main laterally traveling motors and an
auxiliary laterally traveling motor of Fig. 1;
Fig. 8 is a partial side elevational view explaining an
arrangement of the auxiliary trolley of Fig. 1;
Fig. 9 is a partial side elevational view explaining a
state in which the electric room of Fig. 2 is dismounted from
the main girder.
DETAILED DESCRIPTION OF THE INVENTION
A ladle crane according to an embodiment of the present
invention will be explained with reference to Figs. 1 to 8.
Fig. 1 is a plan view explaining an arrangement of the
ladle crane according to the embodiment of the present
invention;
As shown in Fig. 1, the ladle crane (crane) 1 includes an
end tie 3, a main girder (crane main body) 5, an auxiliary
girder 7, a main trolley (trolley) 9, and an auxiliary trolley
(trolley) 11.
Fig. 2 is a side elevational view explaining arrangements
of the main girder and the main trolley of Fig. 1.
As shown in Fig. 2, the end tie 3 is a pair of members
extending along traveling rails 17 disposed to traveling beams
15 and is provided with traveling apparatuses 19 traveling on

the traveling rails 17. As shown in Fig. 1, the end tie 3 has
a main girder 5 and an auxiliary girder 7 attached thereto.
Fig. 3 is a schematic view explaining an arrangement of
the ladle crane of Fig. 1.
The traveling apparatuses 19 are interposed between the
traveling rails 17 and the end tie 3 and cause the ladle crane
1 to travel along the traveling rails 17. In the embodiment
explained here, 4 sets of the traveling apparatuses 19 are
disposed to both the ends of the end tie 3.
As shown in Fig. 3, each traveling device 19 includes
traveling motors (motors) 21A, 21B, traveling motors (motors)
21C, 21D, traveling motors (motors) 21E, 21F, and traveling
motors (motors) 21G, 21H to cause the ladle crane 1 to travel
along the traveling rails 17.
Note that motors used to the traveling motor 21A, 21B,
21C, 21D, 21E, 21F, 21G, 21H are not particularly limited, and
known inverter-controlled motors can be used.
Fig. 4 is a block diagram explaining an arrangement of an
electric circuit in the traveling motors of Fig. 3.
As shown in Fig. 4, the traveling motor 21A, 21B are
supplied with power from a traveling inverter apparatus
(inverter apparatus) 23A. Likewise, the traveling motors 21C,
21D are supplied with power from a traveling inverter
apparatus (inverter apparatus) 23C, the traveling motors 21E,
21F are supplied with power from a traveling inverter

apparatus (inverter apparatus) 23E, and the traveling motors
21G, 21H are supplied with power from a traveling inverter
apparatus (inverter apparatus) 23G. These traveling inverter
apparatuses 23A, 23C, 23E, 23G are supplied with ac power from
the outside.
Note that the traveling inverter apparatuses 23A, 23C,
23E, 23G may control the traveling motors 21A, 21B, 21C, 21D,
21E, 21F, 21G, 21H by subjecting the power supplied therefrom
to variable voltage/variable frequency control, or may subject
the power to constant voltage/constant frequency control,
variable voltage/constant frequency control, constant
voltage/variable frequency control and the like. That is, a
method of controlling the motors is not particularly limited.
The main girder 5 is a pair of beam-like members disposed
to couple the pair of members of the end tie 3 with each other
and has the main trolley 9 placed thereon movably. The main
girder 5 is disposed approximately orthogonal to the end tie 3
as well as disposed outside of the auxiliary girder 7 to be
explained later.
Main laterally traveling rails 27 are disposed on the
upper surface of the main girder 5 (on the surface of the
proximal side to a sheet surface in Fig. 1) so as to extend
along the main girdar 5, and an electric room 29, in which a
main hoist inverter apparatus 59A, and the like are
accommodated, is disposed on a side surface of the main girder

5 (lower surface in Fig. 1).
The main laterally traveling rails 27 have the main
trolley 9 placed thereon and guides it in a direction
approximately orthogonal to the traveling rails 17
(hereinafter, referred to as a laterally traveling direction).
Fig. 5 is a cross sectional view explaining arrangements
of the main trolley, the auxiliary trolley, and the electric
room of Fig. 1.
As shown in Fig. 5, the electric room 29 is a box-shaped
member disposed at a position confronting a side surface of
the main girder 5 (left surface in Fig. 5). As shown in Fig.
2, coupling portions 33 is disposed on the upper surface of
the electric room 29 (upper surface in Fig. 5) so as to be
fixed to a support portion 31 extending from the main girder 5
as well as fitting portions 35 are disposed thereon so as to
be fitted to hooks (not shown) of the crane. A heat
insulating portion 37 is disposed on the lower surface of the
electric room 29 (lower surface Fig. 5) so as to cover the
lower surface. A heat insulating portion 37 is also disposed
on the lower surface of the main girder 5. The electric room
29 is mounted on and dismounted from the support portion 31 by
coupling and separating the support portion 31 with and from
the coupling portions 33.
Disposed in the inside of the electric room 29 are main
hoist inverter apparatuses 59A, 59B, 59C, 59D, an auxiliary

hoist inverter apparatus 87 (refer to Fig. 6), main laterally
traveling inverter apparatuses 67A, 67B, auxiliary laterally
traveling inverter apparatus 95 (refer to Fig. 7), and
traveling inverter apparatuses 23A, 23C, 23E, 23G (refer to
Fig. 4) . While the electric room 29 is attached to the
support portion 31, the main hoist inverter apparatuses 59A,
59B, 59C, 59D and the like are electrically connected to a
main hoist motor 47A and the like to be described later.
Note that it is preferable that the electric room 29 be
approximately as large as a marine container, for example, a
40-feet container. A vessel, a trailer, and the like can be
used by making electric room 29 to the above size, thereby the
electric room 29 can be easily transported from its
manufacturing factory to an iron mill and the like where the
ladle crane 1 is installed.
The 40-feet container has a length of 12.192 m, a width
of 2.438 m, and a height of 2.590 m.
When the main hoist inverter apparatuses 59A, 59B, 59C,
59D cannot be accommodated in the electric room 29 that is
approximately as large as the 40-feet container, the electric
room 29 may be arranged by coupling 2 sets of approximately
40-feet-container-size box members with each other. In this
case, it is preferable to transport the box members from a
manufacturing factory thereof to a site outside of the iron
mill and the like in the vicinity thereof, to fabricate the

electric room 29 by coupling the box members in the site, and
then to bring it into the inside the iron mill and the like.
This is to prevent a lot of dusts existing in the iron mill
and the like from entering into the electric room 29.
As shown in Fig. 1, the auxiliary girder 7 is a pair of
beam-like members disposed to couple the pair of members of
the end tie 3 with each other likewise the main girder 5 and
has the auxiliary trolley 11 placed thereon movably. The
auxiliary girder 7 is disposed approximately orthogonal to the
end tie 3 inside of the main girder 5.
The auxiliary girder 7 has auxiliary laterally traveling
rails 39 disposed thereto.
The auxiliary laterally traveling rails 39 places the
auxiliary trolley 11 thereon and guide it along a lateral
direction.
As shown in Fig. 2, the main trolley 9 is provided with a
main hoist apparatus (hoist apparatus) 43 for hoisting up and
down a ladle (hoisting load) 41 (refer to Fig. 5) and main
laterally traveling motors (motors, first motors) 45A, 45B for
laterally traveling the main trolley 9.
The main hoist apparatus 43 is provided with main hoist
motors (motors, first motors) 47A, 47B, 47C, 47D, main hoist
speed reducing portions 49A, 49B, 49C, main hoist drums 51A,
51B as well as hanging main sheaves 53, a hanging beam 55, and
main hooks 57 as shown in Fig. 5.
/

As shown in Fig. 2, the main hoist motors 47A, 47B and
the main hoist motors 47C, 47D are separately disposed to one
end and the other end ot the main trolley 9. The rotating
drive force of the main hoist motors 47A, 47B, 47C, 47D is
transmitted to the main hoist drums 51A, 51B through the main
hoist speed reducing portions 49A, 49B, 49C.
Motors having such an output that any three sets of them
can hoist up and down the ladle 41, in which the molten steel
is accommodated, and the main hooks 57 as the main hoist
motors 47A, 47B, 47C, 47D.
Note that the main hoist motors 47A, 47B, 47C, 47D are
not particularly limited, and known inverter-controlled motors
may be used for them.
Fig. 6 is a block diagram explaining an arrangement of an
electric circuit in the main hoist apparatus and the auxiliary
hoist apparatus of Fig. 1.
As shown in Fig. 6, the main hoist motors 47A, 47B, 47C,
47D are supplied with ac power from the main hoist inverter
apparatuses (motor controllers, first motor controllers) 59A,
59B, 59C, 59D, respectively. The main hoist inverter
apparatuses 59A, 59B, 59C, 59D are supplied with ac power from
the outside.
An auxiliary hoist switch 61 is connected between the
main hoist inverter apparatus 59D and the main hoist motor 47D
to supply ac power from the main hoist inverter apparatus 59D

to an auxiliary hoist motor 7 5 and to shut off it.
The capacity of the main hoist inverter apparatuses 59A,
59B, 59C, 59D is set larger than that of the auxiliary hoist
inverter apparatus 87 to be described later. Although 500 KW
and 200 KW are exemplified as the capacities of the main hoist
inverter apparatuses 59A, 59B, 59C, 59D and the auxiliary
hoist inverter apparatus 87, they are not limited thereto.
Note that the main hoist inverter apparatuses 59A, 59B,
59C, 59D may control the main hoist motors 47A, 47B, 47C, 47D
by subjecting the power supplied therefrom to variable
voltage/variable frequency control, or may subject the power
to constant voltage/constant frequency control, variable
voltage/constant frequency control, constant voltage/ variable
frequency control and the like. That is, a method of
controlling the motors is not particularly limited.
The main hoist speed reducing portion 49A is interposed
between the main hoist motors 47A, 47B so as to integrally
transmit the rotating drive force of the main hoist motors
47A, 47B to the main hoist reducing portion 49C as shown in
Fig. 1. The main hoist reducing portion 49B is interposed
between the main hoist motors 47C, 47D so as to integrally
transmit the rotating drive force of the main hoist motors
47C, 47D to the main hoist reducing portion 49C.
The main hoist reducing portion 49C is disposed to
I transmit the rotating drive force input from the main hoist

speed reducing portions 49A and 49B to the main hoist drums
51A, 51B.
Note that the main hoist speed reducing portions 49A,
49B, 49C are not particularly limited, and known speed reduces
for transmitting rotating drive force may be used for them.
An arrangement of the main hoist speed reducing portions
49A, 49B, 49C is not particularly limited, and, for example,
three speed reducing portions may be combined, or the rotating
drive force of the main hoist motors 47A, 47B, 47C, 47D may be
transmitted to the main hoist drums 51A, 51 by one reducing
portion.
The main hoist drums 51A, 51B are cylindrical or columnar
members and disposed in parallel with each other to a lateral
direction so as to rotate about a center axis line.
Main wires 63 are wound around the main hoist drums 51A,
51B to hoist up and down the main hooks 57. The main wires 63
are unwound by driving the main hoist drums 51A, 51B in one
rotational direction and rewound by driving it in the other
direction. Note that the main wires 63 are unwound and
rewound in the main hoist drums 51A, 51B at the same time.
The main wires 63 extend from the main hoist drums 51A,
51B to hook side main sheaves 54 and are wound around the hook
side main sheaves 54 and the hanging main sheaves 53, and the
ends of the main wires 63 are fixed to the hanging beam 55.
The hanging main sheaves 53 are cylindrical or columnar

members disposed to the lower surface of the main trolley 9 to
rotate around center axis lines in such a manner that the
center axis lines are arranged approximately in parallel with
the laterally traveling direction.
The hook side main sheaves 54 are cylindrical or columnar
members disposed to the hanging beam 55 to rotate around
center axis lines in such a manner that the center axis lines
are arranged approximately in parallel with the laterally
traveling direction.
As shown in Fig. 5, the main hooks 57 are hooks to be
fitted to a shaft 41a of the ladle 41 and disposed to both the
ends of the hanging beam 55, respectively. As shown in Fig.
2, the main hooks 57 are attached to the hanging beam 55 using
a pin 65 and can be rotated using the center axis of the pin
65 as a center of rotation.
As shown in Fig. 3, the main laterally traveling motor
45A is disposed to one end of the main trolley 9, and the main
laterally traveling motor 45B is disposed to the other end
thereof. As shown in Fig. 2, the rotating drive force
generated by the main laterally traveling motor 45A, 45B is
transmitted to a main laterally traveling portion 9A of the
main trolley 9.
Note that the main laterally traveling motor 45A, 45B are
not particularly limited, and known inverter-controlled motors
may be used.

Fig. 7 is a block diagram explaining an arrangement of an
electric circuit in the main laterally traveling motors and an
auxiliary laterally traveling motor of Fig. 1.
As shown in Fig. 7, the main laterally traveling motor
45A, 45B are supplied with power from the main laterally
traveling inverter apparatuses (motor controllers, first motor
controllers) 67A, 67B. The main laterally traveling inverter
apparatuses 67A, 67B are supplied ac power from the outside.
An auxiliary laterally traveling switch 69 is connected
between the main laterally traveling inverter apparatus 67B
and the main laterally traveling motor 45B to supply ac power
from the main laterally traveling inverter apparatus 67B to
the auxiliary laterally traveling motor 73 and to shut off it.
The capacity of the main laterally traveling inverter
apparatuses 67A, 67B is set larger than that of the auxiliary
laterally traveling inverter apparatus 95 to be described
later. Although 45 KW and 15 KW are exemplified as the
capacities of the main laterally traveling inverter
apparatuses 67A, 67B and the auxiliary laterally traveling
inverter apparatus 95, they are not limited thereto.
Note that the main laterally traveling inverter
apparatuses 67A, 67B may control the main laterally traveling
motors 45A, 45B by subjecting the power supplied therefrom to
variable voltage/variable frequency control, or may subject
the power to constant voltage/constant frequency control,

variable voltage/constant frequency control, constant
voltage/variable frequency control and the like. That is, a
method of controlling the motors is not particularly limited.
As shown in Fig. 1, the auxiliary trolley 11 is provided
with an auxiliary hoist apparatus (hoist apparatus) 71 for
controlling tilt of the ladle 41 (refer to Fig. 5) and the
auxiliary laterally traveling motor (motor, second motor) 73
for laterally traveling the auxiliary trolley 11.
The auxiliary hoist apparatus 71 is provided with an
auxiliary hoist motor (motor, second motor) 75, an auxiliary
hoist speed reducing portion 77, an auxiliary hoist drum 79, a
trolley side auxiliary sheave 81, a hook side auxiliary sheave
83, and an auxiliary hook 85.
As shown in Fig. 1, the auxiliary hoist motor 75 is
disposed to one end of the auxiliary trolley 11. The rotating
drive force of the auxiliary hoist motor 75 is transmitted to
the auxiliary hoist drum 79 through the auxiliary hoist speed
reducing portion 77. Note that the auxiliary hoist motor 75
is not particularly limited, and a known inverter-controlled
motor may be used.
As shown in Fig. 6, the auxiliary hoist motor 75 is
supplied with power from an auxiliary hoist inverter apparatus
(motor controller, second motor controller) 87. The auxiliary
hoist inverter apparatus 87 is supplied with ac power from the
outside.

Note that the auxiliary hoist inverter apparatus 87 may
control the auxiliary hoist motor 75 by subjecting the power
supplied therefrom to variable voltage/variable frequency
control, or may subject the power to constant voltage/constant
frequency control, variable voltage/constant frequency
control, constant voltage/variable frequency control and the
like. That is, a method of controlling the motors is not
particularly limited.
The auxiliary hoist speed reducing portion 77 is disposed
to transmit the rotating drive force of the auxiliary hoist
motor 75 to the auxiliary hoist drum 79.
Note that the auxiliary hoist speed reducing portion 77
is not particularly limited, and a known speed reducer for
transmitting rotating drive force may be used.
The auxiliary hoist drum 79 is a cylindrical or columnar
member and is disposed approximately vertically to the
laterally traveling direction to rotate around a center axis
line.
An auxiliary wire 89 is wound around the auxiliary hoist
drum 79 to hoist up and down the auxiliary hooks 85. The
auxiliary wire 89 is unwound by driving the auxiliary hoist
drum 79 in rotation in one rotational direction and rewound by
driving it rotation in the other direction.
Fig. 8 is a partial side elevational view explaining an
arrangement of the auxiliary trolley of Fig. 1.

The auxiliary wire 89 extends to the hook side auxiliary-
sheave 83 from the auxiliary hoist drum 79 and is wound around
the hook side auxiliary sheave 83 and the trolley side
auxiliary sheave 81, and an end of the auxiliary wire 89 is
fixed to the auxiliary trolley 11.
The trolley side auxiliary sheave 81 is a cylindrical or
columnar member interposed between the auxiliary hoist motor
75 and the auxiliary hoist drum 79 in the auxiliary trolley 11
and disposed to rotate around a center axis line as well as
the center axis line is disposed approximately vertically to
the laterally traveling direction.
The hook side auxiliary sheave 83 is a cylindrical or
columnar member disposed to an auxiliary hook block 91 of the
auxiliary hook 85 and disposed to rotate around a center axis
line as well as the center axis line is disposed approximately
vertically to the laterally traveling direction.
As shown in Fig. 5, the auxiliary hook 85 is a hook
disposed to the auxiliary hook block 91 and hooked to a
tilting metal body 41b disposed to a side wall of the ladle
41.
As shown in Fig. 3, the auxiliary laterally traveling
motor 73 is disposed to the other end of the auxiliary trolley
11. As shown in Fig. 8, the rotating drive force generated by
the auxiliary laterally traveling motor 73 is transmitted to
an auxiliary laterally traveling portion of the auxiliary

trolley 11. Note that the auxiliary hoist motor 73 is not
particularly limited, and a known inverter-controlled motor
may be used.
As shown in Fig. 7, the auxiliary hoist motor 73 is
supplied with power from the auxiliary laterally traveling
inverter apparatus (motor controller, second motor controller)
95. The auxiliary laterally traveling inverter apparatus 95
is supplied with ac power from the outside.
Note that the auxiliary laterally traveling inverter
apparatus 95 may control the auxiliary laterally traveling
motor 73 by subjecting the power supplied therefrom to
variable voltage/variable frequency control, or may subject
the power to constant voltage/constant frequency control,
variable voltage/constant frequency control, constant voltage/
variable frequency control and the like. That is, a method of
controlling the motors is not particularly limited.
Next, a method of transporting the ladle 41 in the ladle
crane 1 arranged as described above.
First, when the ladle 41 is transported, the ladle crane
1 is traveled along the traveling rails 17 as well as the main
trolley 9 is traveled laterally, thereby the main hooks 57 are
moved upward of the ladle 41 as shown in Fig. 2.
When the main trolley 9 is moved upward of the ladle 41,
the main hooks 57 are hoisted down, the main hooks 57 are
hooked to the shaft 41a of the ladle 41, and the ladle 41 is

hoisted up by the main hoist apparatus 43 as shown in Fig. 5.
When the main hooks 57 are hoisted up, ac power is
supplied from the main hoist inverter apparatuses 59A, 59B,
59C, 59D to the main hoist motors 47A, 47B, 47C, 47D of the
main hoist apparatus 43, thereby rotating drive force is
generated from these main hoist motors as shown in Fig. 6. As
shown in Fig. 3, the rotating drive force is transmitted to
the main hoist drums 51A, 51B through the main hoist speed
reducing portions 49A, 49B and the main hoist speed reducing
portion 49C. The main hoist drums 51A, 51B are driven in
rotation by the rotating drive force transmitted thereto.
The main wires 63 are rewound around the main hoist drums
51A, 51B by the rotation of the main hoist drums 51A, 51B,
thereby the main hooks 57 to which the ladle 41 is hooked are
hoisted up.
At the time, the auxiliary hoist switch 61 is turned off,
and the ac power supplied from the main hoist inverter
apparatus 59D is entirely supplied to the main hoist motor
47D.
The main hoist motors 47A, 47B, 47C, 47D are operated by
the same output, and the main hoist inverter apparatuses 59A,
59B, 59C, 59D and the main hoist motors 47A, 47B, 47C, 47D are
operated while remaining power.
When the ladle 41 is hoisted down, the ladle crane 1 is
traveled along the traveling rails 17 as well as the main

trolley 9 is traveled laterally, thereby the ladle 41 is
transported to the vicinity of, for example, a converter and
the like.
When the ladle crane 1 is traveled, ac power is supplied
from the traveling inverter apparatuses 23A, 23C, 23E to the
traveling motors 21A, 21B, 21C, 21D, 21E, 21F, 21G, 21H, and
rotating drive force is generated from the traveling motors
21A, 21B, 21C, 21D, 21E, 21F, 21G, 21H as shown in Fig. 4.
The rotating drive force is transmitted to the traveling
apparatuses 19, thereby the ladle crane 1 is traveled along
the traveling rails 17 until the ladle 41 approaches the
converter and the like.
At the time, the traveling inverter apparatuses 23A, 23C,
23E cause the traveling motor 21A, 21B, 21C, 21D, 21E, 21F,
21G, 21H to generate the same rotating drive force by
controlling the ac power supplied therefrom.
Note that when any of the traveling motor 21A, 21B, 21C,
21D, 21E, 21F, 21G, 21H fails, an ac current supplied to the
failed traveling motor may be shut off by a traveling switch
corresponding to the failed motor. In this case, the ladle
crane 1 is traveled along the traveling rails 17 by the
remaining traveling motors.
As shown in Fig. 7, the main laterally traveling motors
45A, 45B of the main trolley 9 is supplied with ac power from
the main laterally traveling inverter apparatuses 67A, 67B,

thereby rotating drive force is generated from the main
laterally traveling motors 45A, 45B. The rotating drive force
is transmitted to the main laterally traveling portion 9A,
thereby the main trolley 9 is laterally traveled along the
main girder 5 until the ladle 41 approaches the converter and
the like.
At the time, the auxiliary laterally traveling hoist
switch 69 is turned off, and the ac power supplied from the
main laterally traveling inverter apparatus 67B is entirely
supplied to the main laterally traveling motor 45B.
Thereafter, the ladle 41 is tilted by the auxiliary hoist
apparatus 71, and the molten steel in the ladle 41 is poured
into the converter and the like.
When the ladle 41 is tilted by the auxiliary hoist
apparatus 71, first, the auxiliary hook 85 is hoisted down as
well as the auxiliary trolley 11 is laterally traveled to a
position at which the auxiliary hook 85 can be hooked to the
tilting metal body of the ladle 41. When the auxiliary
trolley 11 is laterally traveled, ac power is supplied from
the auxiliary laterally traveling inverter apparatus 95 to the
auxiliary laterally traveling motor 73 of the auxiliary,
trolley 11, thereby rotating drive force is generated from the
auxiliary laterally traveling motor 73 as shown in Fig. 7.
The rotating drive force is transmitted to the auxiliary
laterally traveling portion 93, and the auxiliary trolley 11

is laterally traveled along the main girder 5 up to a position
at which the auxiliary hook 85 is hooked to the tilting metal
body of tne ladle 41.
At the time, the auxiliary laterally traveling switch 69
is turned off, and the ac power supplied from the auxiliary
laterally traveling inverter apparatus 95 is entirely supplied
to the auxiliary laterally traveling motor 73.
When the auxiliary hook 85 is hooked to the tilting metal
body of the ladle 41, it is hoisted upward by the auxiliary
hoist apparatus 71, thereby the ladle 41 is tilted.
When the auxiliary hook 85 is hoisted up, the auxiliary
hoist motor 75 of the auxiliary hoist apparatus 71 is supplied
with ac current from the auxiliary hoist inverter apparatus
87, thereby rotating drive force is generated from the
auxiliary hoist motor 75 as shown in Fig. 6. The rotating
drive force is transmitted to the auxiliary hoist drum 79
through the auxiliary hoist speed reducing portion 77. The
auxiliary hoist drum 79 is driven in rotation by the rotating
drive force transmitted thereto.
The auxiliary wire 89 is rewound around the auxiliary
hoist drum 79 by the rotation of the auxiliary hoist drum 79,
and the auxiliary hook 85 to which the tilting metal body is
hooked is hoisted up. The ladle 41 is turned about the shaft
41a hooked to the main hooks 57, and the molten steel is
poured into the converter and the like from the tilted ladle

41.
Here, mounting/dismounting of the electric room 29 as a
feature of the embodiment will be explained.
Fig. 9 is a partial side elevational view explaining a
state in which the electric room of Fig. 2 is dismounted from
the main girder.
When electric room 29 is replaced, the hooks and the like
of the crane is hooked to the fitting portions 35 of the
electric room 29 as shown in Fig. 2. Then, the support
portion 31 is separated from the coupling portions 33 to
thereby separate the electric room 29 from the support portion
31. As shown in Fig. 9, the separated electric room 29 is
hoisted down by the crane and the like and removed from the
ladle crane 1.
The dismounted electric room 29 is unloaded to a place
where the main hoist inverter apparatus 59A and the like can
be safely and easily replaced and updated. A worker carries
out a job for replacing and updating the main hoist inverter
apparatus 59A and the like in the electric room 29 unloaded
from the ladle crane 1. It is preferable that the place to
which the electric room 29 is unloaded be a place where a less
amount of dusts and the like exist. This is because that
since the iron mill and the like where the ladle crane 1 is
installed contains a large amount of dusts in many cases, when
dusts enter the electric room 29, there is a possibility that

failure of the main hoist inverter apparatus 59A and the like
is caused by the dusts.
When replacement and the like of the main hoist inverter
apparatus 59A and the like are finished, the electric room 29
is hoisted up by the crane again and mounted on the main
girder 5 as shown in Fig. 2. Specifically, the electric room
29 is mounted on the main girder 5 by coupling the support
portion 31 with the coupling portions 33.
According to the above arrangement, since parts such as
the main hoist inverter apparatuses 59A, 59B, 59C, 59D, the
auxiliary hoist inverter apparatus 87, the main laterally
traveling inverter apparatuses 67A, 67B, the auxiliary
laterally traveling inverter apparatus 95, the traveling
inverter apparatus 23A, 23C, 23E, and the like which are
frequently upgraded are intensively disposed in the electric
room 29 on the main girder, devices used for power control
such as the power control semiconductor devices used for the
main hoist inverter apparatus 59A and the like can be easily
replaced and updated. Since the electric room 29 is disposed
independently of the main girder 5, the space in electric room
29 can be more increased as compared with a case in which the
main hoist inverter apparatus 59A and the like are disposed in
the space of the main girder 5. Accordingly, a job for
replacing and updating the above devices in the electric room
29 can be easily carried out. Since the worker can easily

enter into and exit from the electric room 29, he or she can
easily replace and update the above devices.
Since the electric room 29 is detachably mounted on the
main girder 5, the main hoist inverter apparatus 59A and the
like themselves can be replaced in a state that the electric
room 29 is dismounted from the main girder 5. Since the
electric room 29 dismounted from the main girder 5 can be
moved to a place more suitable to replace the main hoist
inverter apparatus 59A and the like, they can be easily
replaced. Exemplified as the place more suitable to replace
the main hoist inverter apparatus 59A and the like is located
lower than a high place where the main girder 5 is disposed
and containing a less amount of dusts and the like.
Otherwise, a time necessary to replace the main hoist
inverter apparatus 59A and the like and to replace and update
the above devices can be reduced by preparing an electric room
different from the electric room 29 to be dismounted from the
main girder 5 and replacing the latter electric room with the
former electric room. The devices, the main hoist inverter
apparatus 59A, and the like which require replacement and the
like can be subjected to the replacement and the like with a
sufficient time after the electric room 29 is dismounted from
the main girder 5.
The main hoist inverter apparatus 59A and the like are
intensively disposed in the electric room 29 and the electric

room 29 is mounted on the main girder 5, by which the number
of parts used to install the main hoist inverter apparatus 59A
and the like can be reduced as compared with a case in which
the main hoist inverter apparatus 59A and the like are
directly disposed in the main girder 5. The inside of the
electric room 29 can be arranged to have a structure suitable
to dispose the main hoist inverter apparatus 59A and the like
therein. Accordingly, the number of the parts used to install
the main hoist inverter apparatus 59A and the like can be
reduced as compared with the case in which they are directly
disposed to the main girder 5.
Since wirings are made collectively from the electric
room 29 to the main girder 5, a labor hour necessary to wiring
work can be reduced as compared with a case in which wirings
are individually made to the main hoist inverter apparatus 59A
and the like. Since the electric room 29 is solely used to
dispose the main hoist inverter apparatus 59A and the like
therein, wirings from the main hoist inverter apparatus 59A
and the like to the outside of the electric room 29 can be
previously made in the electric room 29. Accordingly, a labor
hour necessary to wiring work for replacement and the like of
the devices of the main hoist inverter apparatus 59A and the
like and replacement of the main hoist inverter apparatus 59A
and the like themselves can be easily reduced. When the
electric room 29 is mounted on and dismounted from the main

girder 5, a labor hour necessary to wiring work can be reduced
by bundling wirings between the electric room 29 and the main
girder 5 to a single wiring.
In the ladle crane 1 of the embodiment, since the
electric room 29, in which the main hoist inverter apparatus
59A and the like used to at least one of traveling of the
girders 5, 7, traveling of the trolleys 9, 11, and hoisting of
the ladle 41 are disposed, is detachably mounted on the main
girder 5, the main hoist inverter apparatus 59A and the like
and the devices used in them can be easily replaced. Since
the electric room 29 can be easily carried in and carried out
from the main girder 5, the electric room 29 can be easily
mounted and dismounted by disposing it to the main girder 5.
Since the fitting portions 35 are disposed to the
electric room 29, the electric room 29 can be hoisted down by
other crane, thereby the electric room 29 can be easily
mounted on and dismounted from the crane main body.
In particular, in a large crane such as the ladle crane
and the like, since a large capacity is required to the main
hoist inverter apparatus 59A and the like, the weight thereof
is increased. Since the weight of the electric room 29, in
which a plurality sets of the main hoist inverter apparatuses
59A and the like are disposed, is increased, when the electric
room 29 is mounted on and dismounted from the main girder 5, a
crane must be used to hoist down the electric room 29. Since

the electric room 29 can be easily hoisted down using the
crane because it is provided with the fitting portions, the
electric room 29 can be easily mounted and dismounted..
In the ladle crane 1 of the embodiment, since the
electric room 29 is mounted on the support portion 31 of the
main girder 5 through the coupling portions 33, it can be
easily mounted on and dismounted from the support portion 31.
Since the support portion 31 is disposed so as to project
from the main girder 5 to the outside, when the electric room
2 9 is mounted on and dismounted from the support portion 31,
the electric room 29 is unlike to interfere with main girder 5
and the like, thereby a mounting/dismounting job of the
electric room 29 can be easily carried out. The electric room
29 can be dismounted by separating the coupling portions 33
from the support portion 31, whereas it can be mounted by
coupling the coupling portions 33 with the support portion 31,
which permits the mounting/dismounting job of the electric
room 29 to be carried out easily.
Since the electric room 29 is provided with the heat
insulating portion 37, invasion of heat into the electric room
29 from the outside can be prevented, thereby failure of the
main hoist inverter apparatus 59A and the like caused by heat
can be prevented.
When, for example, the ladle containing molten steel is a
hoisting load, it is preferable that the heat insulating

portion 37 be disposed to the lower surface of the electric
room 29. Invasion of heat radiated from the molten steel can
be prevented by disposing the heat insulating portion 37 as
described above.
Even if the auxiliary hoist inverter apparatus 87 fails,
since the auxiliary hoist motor 75 is operated by the main
hoist inverter apparatus 59D, the electric room 29 can be
dismounted after the girder is moved to a safe position by
hoisting up the auxiliary hook 85.
In particular, even in a state that the molten steel is
contained in the ladle 41, since the electric room 29 is
dismounted after the molten steel in the ladle 41 is charged
into the converter, a wasteful labor hour can be greatly saved
as compared with a conventional crane as well as parts
disposed in the electric room 29 can be promptly and safely
repaired.

We Claim :
1. A ladle crane (1) comprising:
a crane main body (5);
motors;
motor controllers for controlling the output of the motors by
controlling power to be supplied to the motors; and
an electric room in which the motor controllers are disposed,
the ladle crane characterized in that the electric room is
detachably mounted on the crane main body (5).
2. A crane as claimed in claim 1, wherein the crane main body
comprises:
a girder traveling along traveling beams;
a trolley traveling along the girder; and
a hoist apparatus disposed to the trolley for hoisting up and
down a hoisting load,
wherein the motors are used to at least one of traveling of the
girder, traveling of the trolley, and hoisting up and down of the
hoisting load carried out by the hoist apparatuses, and the electric
room is detachably mounted on the girder.
3. A crane as claimed in claim 1, wherein the electric room

comprises fitting portions to be fitted to a crane for hoisting down
the electric room.
4. A crane as claimed in claim 2, wherein:
the girder comprises a support portion disposed thereto so as to
project therefrom to the outside for supporting the electric room;
and
the electric room comprises coupling portions to be detachably
fixed to the support portion.
5. A crane as claimed in claim 1, wherein the electric room
comprises a heat insulating portion for preventing invasion of heat
from the outside.
6. A crane as claimed in claim 1 comprising:
first motors;
a plurality of first motor controllers disposed in the electric
room for controlling the output of the first motors by controlling
the power supplied to the first motors;
a second motor; and
a second motor controller disposed in the electric room for
controlling the output of the second motor by controlling the power
supplied to the second motor;

wherein power can be supplied to the second motor from the first
motor controllers and stopped thereby.
7. A crane as claimed in claim 6, wherein the first motor
controllers are any of a plurality of controllers for controlling a
plurality of hoist motors of a main trolley, respectively; and
the second motor controller is a motor controller of a hoist
motor of an auxiliary trolley.

The present invention relates to a ladle crane (1) comprising a crane
main body (5); motors; motor controllers for controlling the output
of the motors by controlling power to be supplied to the motors; and
an electric room in which the motor controllers are disposed, the
ladle crane characterized in that the electric room is detachably
mounted on the crane main body (5).