Tool changing – Process
Reexamination Certificate
1999-07-26
2001-03-13
Briggs, William (Department: 3722)
Tool changing
Process
C072S446000, C100S22900A, C100S918000, C483S028000
Reexamination Certificate
active
06200245
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention relates to apparatus and method for changing dies, and a press dies for a plate reduction press machine.
2. Prior Art
1.
FIGS. 1 and 2
show an example of a conventional plate reduction press machine; the machine comprises a frame
1
installed at a predetermined location on a transfer line S, provided with guide columns
3
such that the material to be pressed
2
can be moved inside the frame
1
, a lower die holder
4
fixed substantially horizontally at the lower ends of the guide columns
3
, an upper die holder
5
connected to the guide columns
3
so that it can be freely raised and lowered in opposition to the lower die holder
4
across the transfer line S, a crank shaft (not illustrated) located above the die holder
5
, extending substantially horizontally in a direction orthogonal to the transfer line, and supported on the frame
1
by bearings on the non-eccentric portions, and a lower die
8
and an upper die
9
mounted on the lower die holder
4
and the upper die holder
5
, respectively, facing each other, on opposite sides of the transfer line S.
The lower die holder
4
is provided with a dovetail groove
10
extending in the direction of the transfer line, on the upper surface, and a lower slide plate
12
coupled with the dovetail groove
10
in a freely movable manner and the lower die
8
is mounted on the upper surface of the slide plate
12
and coupled to it by means of a cotter pin
11
.
The upper die holder
5
can move up and down with a reciprocating movement along the guide columns
3
when the crankshaft rotates, as the holder is supported and driven by an eccentric portion of the crankshaft. The holder is provided with a dovetail groove
13
extending in the direction of the transfer line, in its lower surface, and provided with an upper slide plate
15
engaging in a freely movable manner with the dovetail groove
13
, and coupled to the upper die holder
5
by the cotter pin
14
.
At the center of the upper slide plate
15
, a through-hole
17
is bored with a peripheral groove
17
a
, and the upper die
9
installed. on the lower surface of the lower die support holder
18
is provided with a flange
18
a
that can engage with the peripheral groove
17
a
of the through-hole
17
and is inserted through the top of-the through-hole
17
.
The crank shaft is connected to the output shaft (not illustrated) of a motor through a universal coupling and a speed reduction gear, and when the motor operates, the upper die holder
5
moves towards and away from the transfer line S, so that the upper die
9
mounted on the die holder
5
via the lower die support holder
18
, also moves towards and away from the lower die
8
.
When the material to be pressed
2
is pressed and formed in the direction of its thickness using the plate reduction press machine shown in
FIGS. 1 and 2
, the motor is operated and the crankshaft is rotated. Then, the material to be pressed
2
is inserted from the upstream A side of the transfer line, into the gap between the upper die
9
and the lower die
8
. The material to be pressed
2
moves from the upstream A side of the transfer line along the transfer line S towards the downstream Side B of the transfer line, while the material is pressed and shaped in the direction of its thickness by the upper die
9
that moves towards and away from the transfer line S according to the movement of the eccentric portion of the crank shaft.
When the lower die
8
is to be replaced, the cotter pin
11
that locates the lower slide plate
12
in the lower die holder
4
is removed, the lower slide plate
12
is pulled out along the dovetail groove
10
of the lower die holder
4
, the lower die
8
is moved out of the plate reduction press machine, the lower die
8
mounted on the lower die holder
4
is released from the lower die holder
4
, and then the lower die
8
is lifted up by a hoist not illustrated and transferred to another predetermined site. Using the same hoist, a new lower die
8
is then lifted up, carried over the lower slide plate
12
and mounted there, and then the lower slide plate
12
is pushed into the center of the plate reduction press machine along the dovetail groove
10
of the lower die holder
4
, and locked on the lower die holder
4
using the cotter pin
11
.
When the upper die
9
is to be replaced, the cotter pin
14
that locates the upper slide plate
15
to the upper die holder
5
is removed, the upper slide plate
15
is pulled out along the dovetail groove
13
of the upper die holder
5
, and is moved out of the plate reduction press machine, the upper die support holder
18
incorporated in the upper slide plate
15
is lifted up by a hoist not illustrated and taken to another predetermined site, and after the upper die
9
is removed from the die support holder
18
, a new upper die
9
is mounted on the upper die support holder
18
, and then the die support holder
18
is lifted up by the hoist and carried above the upper slide plate
15
, and after the holder
18
is positioned in the through-hole
17
of the upper slide plate
15
, the slide plate
15
is pushed in along the dovetail groove
13
of the upper die holder
5
, into the center of the plate reduction press machine, and then locked in the upper die holder
5
by the cotter pin
14
.
However, with the plate reduction press machine shown in
FIGS. 1 and 2
, the wear of the lower and upper dies
8
,
9
is so severe that each die
8
or
9
must be replaced frequently. Consequently, unless the dies are often replaced, the specified capacity of the plate reduction press machine, even if it has a high efficiency, cannot be achieved, and this is a problem.
2. Conventionally, a rough rolling mill is used to roll a slab. The slab to be rolled may be as short as 5 m to 12 m, and a plurality of rough rolling mills are required to roll the slab or the slab must be rolled backwards and forwards in a reversing rolling system, to obtain the predetermined thickness of the slab. In addition, it is planned to use a reduction press machine of which an example is shown in FIG.
3
. The example shows a case in which cranks and connecting rods are used; the cranks
104
are connected to the dies
102
installed above and below the slab
101
, through connecting rods
103
, and the dies
102
are moved up and down to press on the slab. The slab
101
is moved by pinch rolls
106
and the transfer table
107
.
Recently, a continuous casting system has been introduced to produce a long slab, so it is necessary to move the slab continuously to a reduction press machine after it leaves the casting system. When a slab is rough rolled with a rough rolling mill, there is a minimum nip angle (about 17 ∞), and the permissible reduction &Dgr; t per rolling operation is about 50 mm. Reversing rolling cannot be applied because the slab is continuous, therefore to achieve a predetermined thickness, it is necessary to provide a plurality of rough rolling mills in series, or if one rolling machine is used, the diameter of the working rolls must be made much greater. However, such a rough rolling mill with large diameter rolls is difficult to design and manufacture because of its high cost, and furthermore rolls with a large diameter must rotate at a low speed so that the rolls cannot be cooled easily, which results in a short life for the rolls. When a reduction press machine with cranks and connecting rods is used, the slab must be continuously moved even during pressing, so the slab is moved by pulling it with pinch rolls. As a result, there is a large load on the pinch rolls, which makes the size of the entire system large. Consequently, there are many problems with vibration and cost.
To solve these problems, the inventors of the present invention, invented and applied for a patent for the “Thickness reduction press machine” (unexamined Japanese patent application No.10-42328). This machine is shown in FIG.
4
and comprises dies
102
provided above and below the slab
Dodo Yasushi
Fujii Yasuhiro
Ide Kenichi
Ikemune Shozo
Masuda Sadakazu
Briggs William
Griffin & Szipl, P.C.
Ishikawajima-Harima Heavy Industries Co. Ltd.
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