Metal founding – Means to shape a forming surface – Including means for compacting particulate fluent mold...
Reexamination Certificate
1999-05-21
2001-01-23
Batten, Jr., J. Reed (Department: 1722)
Metal founding
Means to shape a forming surface
Including means for compacting particulate fluent mold...
C164S172000
Reexamination Certificate
active
06176296
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an apparatus for pressing a sand mold that is part of an apparatus for producing a mold.
BACKGROUND OF THE INVENTION
One known apparatus for pressing sand molds includes a squeeze board that is made of a rigid plate for pressing molding sand fed into a molding flask. However, that apparatus has a problem in that when required the pressure of the squeeze board cannot be readily varied to correspond to the shape of a pattern. Specifically, since the squeeze board is a rigid plate, although the molding sand located above the upper part of the pattern can be completely pressed, the molding sand located above the lower part of the pattern cannot he completely pressed. As a result, no uniform pressure over all the molding sand can be attained. To overcome this problem, Japanese Utility Model Publication (Kokoku) No. Hei 3-24266 discloses an apparatus for pressing sand molds wherein the squeeze board is elastic.
Also, Japanese Patent Laid-Open (Kokai) No. Hei 1-5642 discloses an apparatus for pressing sand molds wherein a plurality of squeeze heads, each operated by a hydraulic cylinder, are juxtaposed above the molding sand and directed downward such that the pressure of each squeeze head can be varied to correspond to the shape of the pattern. However, this apparatus has a problem in that since a plurality of actuators are necessary to operate each squeeze head, its cost is very high and its structure complex. This apparatus has another problem in that the squeeze head cannot press all of the molding sand near the molding flask.
SUMMARY OF THE INVENTION
This invention was made to overcome these problems. It aims to provide an apparatus for pressing sand molds that can attain a uniform pressure over all the molding sand with a simple structure and less actuators than required in the prior art.
To achieve the purposes of this invention, the apparatus for pressing a sand mold that includes a squeeze board for pressing molding sand fed to a molding flask and an actuator for operating the squeeze board is characterized by the molding flask having at least one bar that connects at least two sides of the molding flask, the squeeze board being positioned above the molding flask and comprising a pressing member and an actuator-connecting member, the pressing member being positioned below the actuator-connecting member and being divided into at least two parts by at least one groove, the groove being positioned and shaped such that it corresponds to the position and shape of the bar so that the bar can enter it, every divided part of the pressing member being attached to the actuator-connecting member, and the actuator being positioned above the squeeze board and connected to the actuator-connecting member so that the actuator vertically moves the squeeze board, thereby vertically moving every divided part of the pressing member.
Uniform pressure over all the molding sand can be attained by increasing the pressure on a sand mold. To do this, the rigidity of the molding flask that is to be put under increased pressure should be strengthened. In this invention, since the molding flask has at least one bar that connects at least two sides of the molding flask, the rigidity of the molding flask is strengthened. However, in the conventional apparatus wherein the rigid or elastic squeeze board has no groove, such a molding flask cannot be used, since the conventional squeeze board collides with the bar. Thus, the bar prevents the squeeze board from being lowered. Although to overcome this problem a plurality of squeeze heads can be used, the problem of a plurality of actuators being necessary is not overcome. In this invention, since the pressing member of the squeeze board is divided into at least two parts by at least one groove that is positioned and shaped such that it corresponds to the position and shape of the bar, the squeeze board can be lowered without colliding with the bar. Therefore, in this invention a molding flask that has a bar can be used to strengthen its rigidity. Thereby, the uniform pressure on the molding sand can be attained by increasing the pressure on the sand molds.
Also, since in this invention every divided part of the pressing member of the squeeze board is attached to the actuator-connecting member, the actuator can vertically move every divided part of the pressing member by vertically moving the squeeze board. Thus, just one actuator suffices to operate the squeeze board. Therefore, the cost of the apparatus can be lowered, and its structure can be simplified, over the prior art.
REFERENCES:
patent: 994626 (1911-06-01), Winfield
patent: 1070293 (1913-08-01), Ronceray
patent: 1137638 (1915-04-01), Lang
patent: 3284858 (1966-11-01), Taccone
patent: 3589433 (1971-06-01), Hedberg
patent: 4915159 (1990-04-01), Damm et al.
patent: 3-24266 (1991-05-01), None
Batten, Jr. J. Reed
Limbach & Limbach L.L.P.
Sintokogio Ltd.
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