Metal working – Method of mechanical manufacture – Disassembling
Reexamination Certificate
2001-11-28
2004-07-20
Rosenbaum, I. Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Disassembling
C029S724000, C029S428000, C029S895000
Reexamination Certificate
active
06763565
ABSTRACT:
The entire disclosure of Japanese Patent Application No. 2001-234625 filed on Aug. 2, 2001 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a roll changing apparatus and a roll changing method for a rolling mill in rolling equipment.
2. Description of the Related Art
There have been roll changing apparatuses for four-high rolling mills as shown, for example, in
FIGS. 14
to
18
.
FIG. 14
shows a roll changing apparatus called a C-hook system. When upper and lower work rolls
100
are to be changed, for example, a lower end receiving portion
103
of a C-hook
102
exclusive to work rolls, which has been suspended from a hook
101
of a crane, is engaged with the shaft ends of the upper and lower work rolls
100
within a rolling mill stand
104
. Then, the upper and lower work rolls (assembly)
100
are slightly lifted by handling of the crane to disconnect them from a lower backup roll (assembly)
105
. (At this time, an upper backup roll (assembly)
105
has been slightly raised.) Then, the upper and lower work rolls
100
are pulled out into a pit P present before the rolling mill. Then, the upper and lower work rolls
100
are transported by the crane to a predetermined site of replacement, where they are changed to new upper and lower work rolls (assembly)
100
. Changing of the upper and lower backup rolls
105
is also performed in a similar manner using a C-hook exclusive to backup rolls.
FIG. 15
shows a roll changing apparatus called a cluster system. When upper and lower work rolls
100
are to be changed, for example, a pit P before a rolling mill is opened, and the upper and lower work rolls (assembly)
100
are stacked on and supported by a lower backup roll (assembly)
105
supported on a sled
106
in a rolling mill stand
104
. (At this time, an upper backup roll (assembly)
105
has been slightly raised.) Then, the sled
106
is moved on a base
108
by a hydraulic cylinder
107
to push out the upper and lower work rolls (assembly)
100
into the pit P before the rolling mill. Then, the upper and lower work rolls (assembly)
100
are changed to new upper and lower work rolls (assembly)
100
by a crane operation. After changing, the new upper and lower work rolls (assembly)
100
are set into the rolling mill stand
104
by the same procedure performed in reverse. Changing of the upper and lower backup rolls
105
is performed, in the case of the lower backup roll (assembly)
105
, by exactly the same procedure as that for the upper and lower work rolls (assembly)
100
, or in the case of the upper backup roll (assembly)
105
, by a similar procedure using a stool (not shown; a so-called dummy for the upper and lower work rolls (assembly)
100
) and placing the upper backup roll (assembly)
105
on the stool.
FIGS. 16 and 17
show a roll changing apparatus called a side shift system. In detail, a four-high rolling mill
50
on a rolling line has a rolling mill stand
51
, upper and lower work rolls
52
as a pair, and upper and lower backup rolls
53
as a pair. In the drawings, Ds denotes a drive side of the rolling line, while Ws denotes a work side of the rolling line.
The above roll changing apparatus has a work roll pushing-out/pulling-in pusher
54
disposed on the drive side Ds of the rolling line, and a backup roll pulling-out/pushing-in hydraulic cylinder
55
disposed on the work side Ws of the rolling line. In
FIG. 16
,
54
a
denotes a connecting fitting at the tip of the pusher
54
,
54
b
denotes a connecting fitting at the end of a roll chock
52
a
of the work roll
52
opposed to the pusher tip,
55
a
denotes a connecting fitting at the tip of the hydraulic cylinder
55
, and
55
b
denotes a connecting fitting at the end of a roll chock
53
a
of the lower backup roll
53
opposed to the tip of the hydraulic cylinder
55
.
Changing of the work rolls
52
is performed by a method which comprises relieving the upper backup roll
53
and the upper work roll
52
to ascending positions, raising the lower work roll
52
to a roll change height, pushing out the lower work roll
52
over a small distance by the pusher
54
, lowering the upper work roll
52
onto the lower work roll
52
to stack them in a roll change posture, pushing out the upper and lower work roll assembly onto a shift table
56
by forward or extended driving of the pusher
54
, replacing this old work roll assembly with a new work roll assembly by a shift or a shifting movement of the shift table
56
caused by a shifting cylinder
64
, and pulling the new work roll assembly into the rolling stand
51
. At this time, the work roll assembly is adapted to act such that wheels
57
mounted on the roll chocks
52
a
of the lower work roll
52
move on up-and-down rails
58
a
in the rolling mill stand
51
and on rails
58
b
on the shift table
56
.
Changing of the backup rolls
53
is performed after pushing the work roll assembly out of the rolling mill stand
51
onto the shift table
56
, and temporarily removing the work roll assembly, the shift table
56
, a detachable girder
62
a
, and a detachable rail
63
a
located before the rolling mill. That is, changing of the backup rolls
53
is performed in the following manner: The connecting fitting
55
a
of the hydraulic cylinder
55
is coupled to the connecting fitting
55
b
on the side of the lower backup roll
53
, and the lower backup roll
53
is pulled out to the work side Ws of the rolling line. At the pullout position, an upper backup roll-loading (roll changing) stool
59
is mounted on the lower backup roll
53
, and they are pushed into the rolling mill stand
51
. The upper backup roll
53
is lowered, and loaded on the stool
59
, whereafter the upper and lower backup rolls
53
are pulled out to the work side Ws by the hydraulic cylinder
55
. At the pullout position, the upper backup roll
53
is replaced with a new upper backup roll
53
. The new upper backup roll
53
is pushed into the rolling mill stand
51
, and set at a predetermined height position. The lower backup roll
53
loaded only with the stool
59
is pulled out to the work side Ws, where the stool
59
is detached, and the lower backup roll
53
is replaced with a new lower backup roll
53
. The new lower backup roll
53
is pushed into the rolling mill stand
51
, and set in place.
At this time, the weight of the assembly including the stool
59
and the upper and lower backup rolls
53
, generally, moves slidingly on a slide base
61
a
in the stand
51
and on a slide base
61
b
on the work side Ws via slide members
60
provided at the roll chocks
53
a
of the lower backup roll
53
.
When roll changing is performed by the above-described C-hook system or cluster system, a changing operation by handling of the crane accounts for most of this task, and requires labor and time. In recent years, therefore, a demand has risen for modifying equipment in order to switch to the side shift system that minimizes a changing operation by handling of the crane and requires minimal downtime for the rolling line.
With the aforementioned conventional side shift type roll changing apparatus, however, large drive devices (pusher
54
and hydraulic cylinder
55
) for bringing the work rolls and the backup rolls into and out of the rolling mill stand are provided separately. Thus, the fixtures cost is high, and installation (accommodation) spaces for them have to be secured.
Furthermore, the shifting girders and rails in an upper part of the backup roll pulling-out pit need to have a separable, detachable rail structure for each rolling mill. Thus, the structure is complicated and upsized, and the cost and construction time involved in modification are increased. Incidentally, the detachable girder
62
a
(and rail
63
a
) has opposite end portions carried by the ends of fixed girders
62
(and rails
63
), as shown in FIGS.
18
(
a
) to
18
(
c
), to take charge of the work roll weight of about 20 to 30 tons per
Mukaigawa Satoshi
Yamamoto Mikio
Yoshihara Osamu
Cuda Rosenbaum I.
Kenny Stephen
Mitsubishi Heavy Industries Ltd.
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