Metal founding – Flask or flask section – Including means to retain or reinforce mold sand or to...
Reexamination Certificate
1998-04-22
2001-03-27
Pyon, Harold (Department: 1722)
Metal founding
Flask or flask section
Including means to retain or reinforce mold sand or to...
C164S411000, C164S394000, C164S207000
Reexamination Certificate
active
06206082
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a molding machine and method wherein a flask and the like are used, and wherein the flask is prevented from being deformed.
DESCRIPTION OF THE PRIOR ART
In conventional molding machines such as an airflow and press molding machine and an air impact molding machine, wherein molding sand is introduced into a flask first, and then a mold space that is defined by the flask and the like is closed, and pressurized air is introduced into the mold space, applying a high pressure to the mold space, for example 0.3 MPa, which is greater than the atmospheric pressure, is necessary. Further, in a conventional molding machine that compacts the molding sand by mechanical force such as a squeeze force, the squeeze output force of the machine sometimes exeeds 1.5 MPa. Thus the pressures to be used in such molding machines have been becoming great.
These molding machines use such high pressures so as to produce molds that have high strength (i.e., high bulk density). However, since these high pressures impart a large force to the flask, it must have a large section in size to prevent it from being deformed. If the flask is deformed, the mold would collapse when the flask is removed from it, or the mold cavity would be deformed. This would result in the size of the mold being inaccurate.
By the way, when a molding machine is used with such a high pressure, and when new facilities that includes this machine and some new flasks are manufactured or obtained, each flask can be one that has a high strength. However, when a conventional, old-type molding line and old-type flasks are used, and when a new air impact molding machine is used instead of the conventional molding machine, the above-mentioned pressurized air or mechanical force cannot be used due to the low strength of the flasks. Thus a mold that has a high bulk density cannot be obtained, or sometimes the desired effect cannot be obtained.
Further, if small, lightweight flasks are used in new facilities, the money to be invested in the transferring facilities of the molding line will be reduced, the energy to be used will be reduced, and the life of the transferring facilities, which is affected by friction, etc., will become long.
The present invention aims to provide a molding method and machine wherein a weak flask, which receives a large force when a mold is produced in it, is prevented from being deformed, or wherein a weak, lightweight metal flask which may be used safely in any line other than a molding line, but which may not be used in a molding line because it is deformed during the molding process, is prevented from being deformed even in the molding process.
SUMMARY OF THE INVENTION
In the method of the present invention, a weak, lightweight flask is encased in a reinforcing means such as a reinforcing frame that reinforces the flask at least when a mold is produced or molding sand is compacted. This prevents the flask from being deformed.
The molding machine of the present invention is one that produces a mold by applying external force of at least one of a pressurized airflow and mechanical compaction to molding sand that is fed into a mold space. The mold space is defined by a flask and a master plate provided with a pattern. The molding machine includes a lifter table for vertically carrying the master plate and the flask, a filling frame that is vertically movable above the lifter table and that comes into contact with the top of the flask, and a reinforcing frame that is vertically movable below the flask. The reinforcing frame and the flask relatively approach each other so that the reinforcing frame contacts the outer surface of the flask to reinforce the flask.
This invention enables molding machines such as an airflow and press molding machine, which provides a mold that has a high bulk density, and that can produce a high-quality cast, to be incorporated in conventional facilities.
Further, this invention enables such facilities to use lightweight, small flasks, so that the money to be invested in the transferring system of such facilities and the energy used in the facilities can be reduced, and so that the life of the facilities, which is affected by inherent friction, etc., will become long.
In this invention, producing a mold using a flask and the like means producing a mold wherein pressurized air is introduced from an air tank of an airflow and press molding machine or an air impact molding machine into a mold space defined by the flask and the like to compact molding sand in the mold space. It also means producing a mold wherein the molding sand is further compacted after such an airflow introduction by a mechanical force such as squeezing force. It also means producing a mold wherein molding sand in the mold space is compacted only by mechanical force. A squeezing force is a typical example of a mechanical force. Thus the mechanical force is not limited to it.
Further, the reinforcing frame, which is an example of reinforcing means, preferably has an inner surface shape that is similar to the outer surface shape of the flask. The material of the frame is preferably metal, because it wears less than other materials. However, the frame is not limited to metal, and it may be of any material, if it has enough strength.
The frame preferably has a strength greater than that of the flask, in order to resist the force that is imparted to the flask while a mold is produced. Alternatively, the assembly of the frame and the flask may have enough strength to resist that force. More preferably, the frame has a strength greater than the pressure that the molding machine uses to produce a mold. If it has such a strength, the flask held in it will not be deformed. When the weight of the flask is a problem, the strength of the assembly or combination of the flask and the frame is made to be greater than that of the force used by the machine.
REFERENCES:
patent: 939849 (1909-11-01), Millar
patent: 4063586 (1977-12-01), Keller
patent: 4351098 (1982-09-01), Hanna
patent: 55-154655 U (1980-11-01), None
patent: 55-154652 U (1980-11-01), None
patent: 10-146648 (1998-06-01), None
patent: 619279 (1978-08-01), None
Limbach & Limbach L.L.P.
Lin I.-H.
Pyon Harold
Sintokogio Ltd.
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