US2841841A - Method and apparatus for molding - Google Patents

Description

July 8, 1958 Filed Sept. 6, 1956 R. J. HINES METHOD AND APPARATUS FOR MdLDING 2 Sheets-Sheet 1 IN VEN TOR.

'Russeu. J. Hiues July 8; 1958 R. J. HlNES METHOD AND APPARATUS FOR MOLDING 2 Sheets-Sheet 2 Filed Sept. 6, 1956 INVLFNTOR. 'Russsu. J. Hmss Misrnon nun nrrnns'ros non MOLDING Russell J. Hines, Lakewood, Ohio, assignor to The Hines Final; Company, @ieveland, Ohio, a corporation of @hio Application depteiniser d, 1956, Serial No. 603,394

1 Claim. (Cl. 22-9t) This invention relates to a method and apparatus for making sand molds for castings and more particularly to molds that are used in foundries for making metallic castings.

In one of the methods used for making metal castings, a pattern plate is placed on the bed plate of a press, the pattern plate having the cope forming portion of a pattern thereon. A rectangular sand measuring frame of predetermined dimensions is then placed upon the flask in aligned relationship therewith. Sand is inserted loosely into the flask and into the frame until the sand reaches the top level of the frame. Next, the operator levels off the top of the sand even with the top surface of the frame by any suitable means, as for example by a straight-edged blade. The frame is dimensioned so that at the completion of the last operation, the flask and frame contain substantially the exact amount of sand required to assure uniform compacting of the sand under a predetermined force exerted by a press head. The rectangular frame is then removed, after which an endless member or band is inserted into the flask and is supported upon the sand, with a portion of the band projecting above the top of the flask. The squeezing operation is then commenced, whereby a press head having a pattern plate on the under surface thereof is forced down onto the top of the sand and onto the band therein. The squeezing operation is continued until the press head has completed the full extent of its movement. This occurs while the top of the band and likewise the top surface of the sand are above the top surface of the flask. Thereafter, the filled flask is transported to a pouring station and the flask is removed from the mold. The operation of flask filling and band inserting is repeated, whereupon a second mold section is superimposed upon the first, the flask is removed and, in the case of stack molding, the operation is repeated until the desired number of molds suitable for pouring is obtained.

The grouping of a plurality of sand molds together to enable their pouring in one operation will be hereinafter referred to as stack molding. It envisions the vertical stacking of one mold on top of the other in such manner that the various pouring sprues of a stack moid register with each other to enable simultaneous casting of a great many articles of desired form. In stack molding, the band remains embedded within the sand of each section after the flask is removed and provides a reinforcement against bursting of the stack upon the introduction of the molden metal thereto.

One of the difficulties encountered in the above method is the inadvertent spilling of sand down the sides of the flask and into the latching mechanism and hinges thereon, whenever the flask is filled with sand, thus causing faulty operation or premature wear of such parts. Another difliculty is the fact that the frame does not ice 2 lend itself readily to bequickly and easily lined up with the flask after it is placed thereon for the flask filling operation.

An object of the present invention is to provide a method and apparatus for making sand molds in which the sand is prevented from entering the flask hinges and latch mechanism during the flask filling operation.

Another object of the invention is to provide a method and apparatus for making sand .molds using a sand measuring frame that may be quickly and easily lined up with the flask in preparation for the flask filling operation, and that may be quickly and easily withdrawn from the flask and sand therein after the completion of the flask filling operation.

Briefly, the foregoing objects are accomplished by supporting an empty molders flask upon a pattern plate, which in turn, rests upon a press bed plate. The pattern plate has a cope-forming portion of a pattern on the upper surface thereof. A sand measuring frame including a sand shed having an endless band strip portion on the inner periphery thereof is then placed upon the flask. The frame is configured in cross-section so that the sand shed portion rests upon the top of the flask and the band strip portion is telescoped partially into the flask. This construction enables the operator to quickly and accurately align the frame with the flask. The outside dimensions of the frame are slightly less than the inside dimensions of the flask to facilitate the latter operation. Next, sand is inserted loosely into the flask and into the frame until the sand reaches the top level of the frame. The operator then levels off the top of the sand even with the top surface of the frame by any suitable means, as for example by a straight-edged blade. To prevent the sand from falling down the sides of the flask and into the flask hinges and latch mechanism, a downwardly sloping skirt or apron is provided on the sand shed portion of the frame, which is adapted to carry any excess sand (removed from the top of the frame by the paddle) over and away from the sides of the flask. The frame is dimensioned so that at the completion of the last operation the flask and frame contain substantially the exact amount of sand required to assure uniform compacting of the sand under a predetermined force exerted by the press head. Next, the frame is removed from the sand-filled flask, this operation being facilitated by a downwardly and outwardly extending taper on the inner peripheral surface of the band strip portlon. An endless band member is then inserted into the frame and flask and is supported upon the sand with a portion of the band projecting above the top of the flask. The squeezing operation is then commenced whereby a press head having a pattern plate on the under surface thereof is forced down onto the top of the sand and onto the band therein. The squeezing operation is continued until the press head has completed the full extent of its movement. This occurs while the top of the band and likewise the top surface of the sand are above the top surface of the flask. Thereafter the filled flask is transported to a pouring static-11 and the flask is removed from the mold, thus leaving the band embedded in the sand as a reinforcement for the mold. The operation of flask filling and band inserting is then repeated, whereupon a second mold section is superimposed upon the first, the flask is removed and, in the case of stac.

molding, the operation is repeated until the desired number of molds suitable for pouring is obtained.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings in which;

Fig. l is a vertical sectional View through a mold section which is made in accordance with the present invention;

Fig. 2 is a side elevational view of a molders flask interposed between the bed plate and press head of a foundry press and showing a step in the formation of a mold section; in this view, the flask, the bottom pattern plate and the band are shown in vertical section;

Fi 3 is a view similar to Fig. 2 but showing an additional step in the formation of a mold section;

Fig. 4 is a perspective view of a sand measuring frame which is placed upon the flask in carrying out the method of the invention; in this view the frame is on a scale reduced from that shownin Fig. 1;

Fig. 5 is a perspective view of the flask used in carrying out the method of the present invention;

Fig. 6 is a side view showing a stack of mold sections made in accordance with the method of the present invention;

Fig. 7 is a perspective view of the band member which is inserted into the flask in carrying out the method of the invention. in this view, the band is on a scale reduced from that shown in Fig. 5.

The present invention is adapted for making a single mold cavity by superimposing a cope section over a drag section, and is also adapted for stack molding.

Referring to the drawings, there is shown a flask F which comprises the side walls 10 and 11 and the end walls 12 and 13. The walls are pivotally interconnected at one corner by a hinge 14 (Fig. 5), and may be separably interconnected at a diagonally opposite corner by a latch mechanism 16 to form a rectangular frame which is open at the top and bottom.

In forming a mold section, a pattern plate 20 is fixed to the bed plate 22 of a foundry press (Fig. 1) and has a cope forming portion 21 of a pattern thereon. The empty flask F is placed upon the plate 20 in aligned relationship therewith. A rectangular sand measuring frame or sand shed A (Figs. 1 and 4) is placed on the flask in aligned relationship therewith, and includes a sand shed portion B having an endless band strip portion or member S suitably secured to the inner periphery thereof, as for example by the bolts 26. If desired, however, the frame A may be cast in one piece. The strip S includes the side walls 31 and 32 and the end walls 33 and 34. Although the frame in the present instance is rectangular, it may be of any suitable configuration to complement the flask. The frame is configured in cross section (Fig. 1) so that the sand shed portion B rests upon the top of the flask and the band strip portion S is telescoped partially into the flask as shown. This construction enables the operator to quickly and accurately position the frame on the flask in preparation for the flask filling operation. The outside dimensions of the frame are slightly less than the inside dimensions of the flask as shown by the clearance 2'7 to facilitate the latter operation. The flask with the frame A centered thereon is then filled with sand 29 to the top surface of the frame. At this point, the operator may smooth off the top surface of the sand flush with the top surface of the frame with a straight-edged blade or the like. The top portion of the frame extends above the top of the flask by an amount suflicient to measure a predetermined quantity of sand inserted into the flask at the completion of the last operation. To prevent the excess sand from falling down the sides of the flask and into the flask hinges and latch mechanism, a diagonal downwardly sloping wall or skirt 2.8 is provided on the sand shed portion B of the frame which carries or deflects the excess sand over and away from the sides of the flask. The flask and frame now contain substantially the correct volume of sand required to assure uniform compacting of the sand upon exertion of the full force of the press. The frame A is then removed from the sandfilled flask. To facilitate its removal from the sand, the inner surfaces of the ' band strip walls 31, 32, 33 and 34 4 are tapered downwardly and outwardly as shown in Fig. 1 (with respect to the walls).

Next, an endless band member M (Fig. 7) having the side walls 35 and 36 and the end walls 37 and 38 may be placed around the projecting portion 39 (Fig. 2) of the sand and supported upon the shoulder 30, which extends around the outer periphery of the projecting portion 39 and which was formed by the bottom side of the strip S in the last operation. When the band member M is positioned in the flask, a portion of it will project above the top of the sand as shown. The band member is complementary to and has a close fitting, but sliding engagement with the side and end walls of the flask.

A press head 40 having a pattern plate 41 on the underside thereof is used for the squeezing operation upon the sand. The plate 41 carries the drag portion 42 of a pattern, which matches the cope portion 21 on the plate Ztl. Next, the squeezing operation is commenced wherein the band is forced down into the flask until the press head is moved to the fullest extent permissible under the available pressure acting upon the head. Such pressure is suflicient to obtain adequate compacting of the sand without forcing the band entirely into the flask as shown in Fig. 3. Simultaneously, the drag portion of the mold cavity is formed in the top surface of the sand while the cope portion is formed in the bottom surface of the cand. During this operation, a smooth marginal surface 45 is formed around the periphery of the mold cavity. This serves as a support for the superimposed mold section.

After the squeezing operation, the filled flask is removed from the press and is transported to a pouring station and the flask is removed. This leaves the mold section (Fig. 6) as self supporting, with the band member M imbedded in the sand as a reinforcement for the mold.

The empty flask is returned to the press and placed upon the pattern plate 20 and the operation above described is repeated. The second filled flask is then removed from the press, transported to the pouring station, and superimposed upon the mold section 50 and the flask is removed. This leaves the mold section 51 superimposed upon the mold section 50, at which time the cope cavity in the mold section 51 is in registration with the drag cavity of section 50, thus forming a complete mold cavity. The single mold cavity may be filled with metal after the mold section 51 is placed in the mold section 50.

For stack molding, additional mold sections, identical with those designated 50 and 51 are subsequently made and superimposed upon the stack, as at 52, 53, 54, 55 and 56, after which the stack may be poured in the usual way. Thus, each mold section has a reinforced band embedded therein, which acts as a reinforcing means to prevent any of the molds in the stack from bursting. In Fig. 6 the flask F is shown in broken lines as illustrating the position of the flask before removal after the section 56 is placed upon section 55.

The terms and expressions which have been employed are used as terms of description and not of limitation and there is no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown or described or portions thereof.

I claim:

A sand measuring frame for use with a rectangular foundry molding flask comprising an endless band strip member and a separable skirt portion releasably secured thereto, said band strip member including side and end walls joined in the form of a rectangle to form a configuration complementary to the flask, said skirt portion comprising an endless wall detacha'bly secured to the upper edge of said side and end walls and extending downwardly and outwardly therefrom, said skirt portion being adapted to engage and be supported upon the top of the flask and overhang the same on all sides in a manner allowing the lower portion of the band strip member to 2,841,841 6 be telescoped into the flask in close proximity with the References Cited in the file of this patent walls thereof and allowing the upper portion of the band strip member to extend above the flask by an amount suf- UNITED STATES PATENTS ficient to measure a predetermined quantity of sand to be 177,395 Hammer May 16, 1876 inserted into the flask, said skirt portion being adapted 5 485,764 Keenan Nov. 3, 1892 to carry excess sand over and away from the Walls of the 738,279 Beckwirh Sept. 8, 1903 flask during the sand filling operation, said side and end 1,120,759 Swift Dec. 15, 1914 Walls having the inside surfaces thereof tapered down- 1,291,108 Peck Jan. 14, 1919 Wardly and outwardly to facilitate the removal of the 2,006,240 Hines June 25,1935

frame from the flask after the sand filling operation. 10 2,472,015 Henkel May 31, 1949

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