Dispensing – Molten metal dispensing – Flow controllers or assists
Reexamination Certificate
2001-03-02
2002-05-07
Kastler, Scott (Department: 1742)
Dispensing
Molten metal dispensing
Flow controllers or assists
C222S597000
Reexamination Certificate
active
06382477
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to molten metal pouring amount control apparatus which is attached to a bottom of a molten metal container such as a ladle and tongue dish and slides a sliding plate to adjust an opening of a nozzle hole between the sliding plate and a fixed plate so as to control a molten metal pouring amount.
2. Description of the Related Art
Usually, the molten metal pouring amount control apparatus comprises a fixed plate made of refractory product detachably attached to a base plate fixed on a ladle or the like having a nozzle hole and a sliding plate made of refractory product detachably attached to a slide frame having a nozzle hole. By sliding the slide frame along the base plate, openings of a nozzle hole of the fixed plate and that of the sliding plate are adjusted so as to control a pouring amount of molten metal.
The sliding type of the slide frame in such a molten metal pouring amount control apparatus includes metal sliding type and roller sliding type.
Examples of the metal sliding type have been disclosed in Japanese Patent Application Publication No. 48-4697, Japanese Patent Application Publication No. 7-75771 and Japanese Patent Application Laid-Open No. 7-164134.
According to this metal sliding type, a sliding face between the fixed plate and sliding plate and a sliding face between the slide frame and guide member are coated with lubricant so that the sliding plate is pressed against the fixed plate through the slide frame so as to prevent a leakage of molten metal. To slide the slide frame to adjust the opening of the nozzle hole, a driving force larger than a sum of a frictional force generated on the sliding face between the fixed plate and sliding plate and a frictional force generated in the sliding face between the slide frame and guide member is necessary.
In this case, because the frictional force generated between the slide frame made of metal material and guide member is large, a high-output driving means (usually, a hydraulic cylinder is used) is necessary for driving the slide frame and a strength sufficiently capable of bearing a high load is needed.
Further, because the slide frame and its guide members are worn out, they need to be replaced with new one before or after 500 heats for example. Thus, maintenance cost such as disassembly cost and parts cost increases. Further each time when molten metal is charged, the sliding face between the fixed plate and sliding plate and the sliding face between the slide frame and guide member must be coated with lubricant, and this work is troublesome.
However, according to the metal sliding type, a spring force application point always exists below the nozzle hole of the fixed plate and nozzle hole of the sliding plate even if the slide frame is slid. Therefore, there is an advantage that a pressing force around the nozzle hole which is the most important is secured and this is why the metal sliding type has been widely used up to now.
The other type of roller sliding was invented to solve a problem on friction generated in the aforementioned metal sliding type and has been disclosed in, for example, Japanese Patent Publication No.SHO62-58816 and Japanese Patent Publication No.HEI1-38592.
According to the former invention, as shown schematically in
FIG. 12
, rollers
107
a
,
107
b
are provided at fixed positions on a guide member
106
and a slide frame
105
having the sliding plate
103
is installed on these rollers
107
a
,
107
b
. Then, the sliding plate
103
is pressed against a fixed plate
101
by a spring
108
interposed between a casing cover
109
and a guide member
106
(hereinafter this is referred to as a fixed roller type) According to the latter invention, as shown schematically in
FIG. 13
, the rollers
107
a
,
107
b
are provided on the slide frame
105
and then, mounted on the guide member (rail). The sliding plate
103
is pressed against to the fixed plate
101
by the spring
108
(hereinafter this is referred to as moving roller type).
Such a roller sliding type is capable of reducing a frictional force generated in sliding of the sliding plate by using the rollers and reduction of its unit price and maintenance cost can be expected.
In the fixed roller type of the aforementioned roller sliding type, when the nozzle holes
102
,
104
are fully opened, as shown in FIG.
12
(
a
), the pressing force of the sliding plate
103
is applied around the nozzle hole
102
of the fixed plate
101
by the rollers
107
a
,
107
b
uniformly, so that portions around the nozzle holes
102
,
104
make firm contact with each other. Thus, there is no fear that any molten metal invades in between the fixed plate
101
and sliding plate
103
.
However, because the positions of the rollers
107
a
,
107
b
are constant, as the slide frame
105
is moved in a direction for closing the nozzle holes
102
,
104
(direction indicated by an arrow), as shown in FIG.
12
(
b
), acting points of the rollers
107
a
,
107
b
against a portion around the nozzle hole
104
of the sliding plate
103
are moved, so that the pressing force applied around the nozzle hole
104
becomes unstable. Further, when the nozzle holes
102
,
104
are closed fully, as shown in FIG.
12
(
c
), the nozzle hole
104
is apart from the acting points of the rollers
107
a
,
107
b
, so that the pressing force around the nozzle hole
104
drops.
In this condition, molten metal is likely to invade in between the fixed plate
101
and the sliding plate
103
through the nozzle hole
102
. If the invading molten metal is solidified, the contact of the sliding plate
103
by pressing with the springs
108
becomes difficult, so that a leakage of the molten metal is generated from a gap between the both plates.
On the other hand, in case of the moving roller type, although the pressing force around the nozzle hole
104
in the sliding plate
103
is stabilized different from the case of the fixed roller type, as shown in FIG.
13
(
a
), the pressing force around the nozzle hole
102
in the fixed plate
101
drops as the slide frame
105
is moved in a closing direction (direction indicated by an arrow) as shown in FIGS.
13
(
b
), (
c
). Therefore, the same problem as the case of the fixed roller type is generated.
In such a fixed roller type and moving roller type, if a distance between the rollers
107
a
and
107
b
is made long, the pressing force around the nozzle holes
102
,
104
can be secured in an entire range from the full opening of the nozzle holes
102
,
104
to the full closing thereof. In this case, naturally, the slide frame
105
, guide member
106
and casing cover
109
have to be extended. Consequently, the entire apparatus becomes very long, so that not only increase of cost is induced, but also this apparatus may not be mounted on a bottom face of the molten metal container.
Further, because the rollers
107
a
,
107
b
have to be reduced in size, the service life of shafts for supporting them is short and therefore they have to be replaced sometimes. Thus, maintenance cost cannot be saved sufficiently. Further, because complicated parts such as a lever and the like in the invention described in the aforementioned Japanese Patent Publication No.SHO62-58816 and an intermittent rail and the like in the invention described in Japanese Patent Publication No.HEI1-38592 are necessary, reduction of the price of the apparatus cannot be expected.
For the reason, although the molten metal pouring amount control apparatus based on the roller sliding type has a technical advantage that the sliding friction of the slide frame is small, it cannot currently be in a mainstream of sliding type of the slide frame.
Accordingly, a first object of the present invention is to solve the above described problems and provide a molten metal pouring amount control apparatus in which the sliding resistance of the slide frame is small and the pressing force around the nozzle hole is stabilized so that there is no fear that any trouble such as a leakag
Tsuru Masahiro
Yamamoto Hironori
Anderson Kill & Olick
Kastler Scott
Lieberstein Eugene
Meller Michael N.
Tokyo Yogyo Kabushiki Kaisha
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