US2767446A - Molding machine - Google Patents

Description

Oct. 23, 1956 H. L. PRAY MOLDING MACHINE Filed Sept. 12, 1955 INVEN TOR. HAROLD L. PRAY.

MOLDING MACHINE Harold L. Pray, Dearborn, MiclL, assignor to Kelsey- Hayes Wheel Company, Detroit, Mich., a corporation The invention relates to machines for making sand molds and refers more particularly to devices for forming pouring cups and sprues in sand molds.

The invention has for one of its objects to provide an improved device for forming a pouring cup and sprue in a sand mold while it is being formed.

The invention has for another object to provide an improved device in which the forming of the pouring cup is facilitated by air under pressure.

These and other objects of the invention will become apparent from the following description taken in connection with the accompanying drawings in which-- Figure l is a sectional view of a portion of a molding machine embodying the invention;

Figure 2 is a plan view of the mold formed by the molding machine.

The invention is designed particularly for use in a conventional molding machine of the diaphragm type in which 1 is the head in which is clamped the periphery of the diaphragm 2 for packing or squeezing the molding sand within the flask 3. The flask is mounted on the pattern plate 4 which in turn is mounted on the base 5. The base carrying the pattern plate and the flask with the latter filled with molding sand is adapted to be moved under the head. The diaphragm, which is flexible, is adapted to be forced against the molding sand in the flask by air under pressure admitted to a chamber closed by the diaphragm to pack or squeeze the sand upon and around the pattern carried by the pattern plate. The diaphragm is adapted to be returned to its normal raised pos1t1on clearing the flask by withdrawing air from the chamber and creating sub-atmospheric pressure.

To form a pouring cup and sprue in the sand mold, I have provided the opening 6 in the pattern plate 4, the upright tubular member 7 secured to and mounted on the pattern plate and the pouring cup form 8 mounted on and secured to the diaphragm. The tubular member has the portion 9 fitting and preferably threaded in the opening 6 and the portion 10 extending upwardly from the lower portion and formed with an upwardly tapered outer surface. An annular shoulder 11 is formed between the portions 9 and Ill to rest against the pattern plate. The tubular member and particularly its upper portion 10 abuts the one or more gate-forming portions of the pattern or patterns. The pouring cup form 8 has its portion of greater area fixedly secured to the lower side of the diaphragm 2 in such a position with respect to the adjacent portion of the periphery of the diaphragm clamped to the head that the form registers with the tubular member and the portion of the form of smaller area engages the upper end of the tubular member when the diaphragm is flexed downwardly by air under pressure. The form is preferably made of rubber vulcanized to the diphragm which is also preferably made of rubber.

For the purpose of facilitating the forming of the pour- States Patent 0 ing cup by the form 8, air under pressure is conducted to the interior of the tubular member 7 during the downward movement of the diaphragm and form and this air forms a generally frusto-conical space in the molding sand above the tubular member so that the form 8 may be more readily moved downwardly against the upper end of the tubular member. I11 the present instance, the base 5 is formed with the upwardly opening chamber 12 registering with the opening 6 and with the passage 13 extending laterally to the chamber 12 and formed preferably of a pipe connected outside the base to the flexible hose 14 for conducting air under pressure to the pipe.

In operation, with the base 5 in position locating the flask filled with molding sand underneath the machine head, air is admitted through the flexible hose 14 at the same time air is admitted into the chamber of the head above the diaphragm 2 and the air passing through the tubular sprue-forming member '7 forms a frusto-conical space or recess in the molding sand above this member facilitating the downward movement of the pouring cup form. By creating vacuum in the chamber in the machine head, the diaphragm carrying the form is raised to clear the flask after which the base carrying the pattern plate, flask and completed mold may be removed from beneath the head after which the flask and completed mold may then be removed from the pattern plate, pattern and sprue-forming member. At this time the space which had been formed by the upper portion of the sprue-forming tubular member communicates with the one or more mold cavities through the one or more gates.

What I claim as my invention is:

1. In a molding machine for making a sand mold of the type having a diaphragm movable downwardly against sand in a flask to pack the same, a pouring cup and sprueforming device comprising a pattern plate, an upright hollow sprite-forming member on said plate, a pouring cup form on the diaphragm movable therewith and into registration with and downwardly against said sprueforming member to form a pouring cup in the sand, and means for conducting air under pressure to said sprucforming member.

2. In a molding machine for making a sand mold of the type having a pressure-applying member for packing sand in a flask, a pouring cup and sprue-forming device comprising a pattern plate having an opening therethrough, an upright tubular sprue-forming member on said plate registering with the opening, a pouring cup form on said pressure-applying member movable therewith and against the upper end of said tubular member to form a pouring cup in the sand, and means for conducing air under pressure to the opening.

3. In a molding machine for making a sand mold of the type having a pressure-applying member for packing sand in a flask, a pouring cup and sprue-forming device comprising a pattern plate having an opening therethrough, an upright tubular sprue-forming member on said plate registering with the opening, a pouring cup form on said pressure-applying member movable therewith and against the upper end of said sprue-forming member to form a pouring cup in the sand, and a support for said pattern plate having a passageway for conducting air under pressure to the opening.

References Cited in the file of this patent UNITED STATES PATENTS 2,698,976 Taccone Jan. 11, 1955 FOREIGN PATENTS 239,567 Germany Oct. 16, 1911

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