US3143775A - Foundry molding machine - Google Patents

Description

A. R. JONES 3,143,775

Aug. 11, 1964 FOUNDRY MOLDINGMACHINE Filed May 17, 1961 36 i# if, @l

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ATTORNEY United States Patent O 3,143,775 FGUNDRY MOLDING MACI-IDIE Arthur R. Jones, Danville, Ill., assigner to General Meters Cerperation, Detroit, Mich., a corporation of Delaware Filed May I7, 196i, Ser. No. 110,772 Qlairns. {CL 22-4l) This invention relates to a foundry molding machine and particularly to a molding machine having a powerdriven roller which packs sand rmly into a mold flask before the sand is further compressed by means of a flexible diaphragm.

In the past, foundries using sand molding machines employing pneumatic pressure-operated diaphragms to pack sand around a metal pattern in a mold llask have encountered problems of molten metal runout unless the ask was appreciably deeper than the thickness of the pattern. A ask of average depth frequently did not contain sufficient sand around the pattern after the molding operation. Moreover, when a simple knock-olf plate is used during the sand molding cycle to remove the excess sand on top of the pattern in the ask, much of the sand is spilled on the floor around the molding machine.

United States Patent No. 2,852,820 Taccone describes and claims an improved diaphragm-type molding machine. This machine reduces the seriousness of the aforementioned runout problem by providing a roller strike-olf to replace the strike-olf plate previously employed. Nevertheless, diaphragm molding machines using the Taccone roller strike-oi still are not completely successful in eliminating the problem of casting metal runout when relatively shallow mold flasks are employed, particularly if the conguration of the pattern is such as to accentuate this problem.

Accordingly, a principal object of the present invention is to provide a diaphragm-type molding machine with a power-driven sand-packing roller which eliminates molten metal runouts by increasing the thickness of the sand layer above the pattern after it has been compressed by a pneumatic pressure-operated diaphragm. Sand prepacked in this manner also results in molds having considerably harder edges and better mold definition.

Other objects and advantages of this invention will more fully appear from the following detailed description of a foundry sand molding machine having a power-driven, sand pre-packing roller, reference being made to the accompanying drawing in which:

FIGURE 1 is a side View, with parts broken away and in section, of a molding machine constructed in accordance with the present invention;

FIGURE 2 is a fragmentary end View of the molding machine shown in FIGURE 1 with the sand chute being omitted to more clearly show structural details of the machine; and

FIGURE 3 is an enlarged sectional view along the line 3-3 of FIGURE 2, showing the construction of the power-driven sand pre-packing roller.

Referring more particularly to the drawing, the diaphragm-type foundry sand molding machine shown in FIGURE l has a base It), which supports a molding head 12 by means of four vertically extending steel rods 14. The threaded upper ends of these rods are connected to the head by means of nuts 16, while the lower ends of the rods threadedly engage the base at lateral projections 18.

The molding head 12 is provided with a depending section 20 containing a flexible diaphragm 22, which is secured at its periphery in an airtight manner to the side walls of the head. An electric motor 24 is mounted on the head by means of a bracket 26. This motor drives a blower 28 to thereby provide a means for evacuating lCC the enclosed space or chamber 30 in the head above the diaphragm. The chamber 30 also can be supplied with compressed air through a pipe or conduit 32 having a suitable valve (not shown) to regulate the air flow, thus providing means for forcing the diaphragm downwardly to contact and further compress pre-packed sand in a cope or drag half of a metal flask 34.

This flask rests on the upper surface of a pattern plate 36. In turn, this plate is supported on a set of rollers 38 which are mounted horizontally on a truck 40. A piston within an air cylinder 42 is connected to the truck. Reciprocation of the piston, which is connected to the ask by suitable mechanical linkages (not shown), serves to lift the flask 34 off the pattern plate 36 and pattern 44.

The truck 40 is moved horizontally between its sandloading station underneath a sand chute 46 and the moldforming station beneath the molding head 12 by means of a double-acting air cylinder and piston (not shown) located in the base 10 of the molding apparatus. Air pressure is alternately applied to opposite sides of the piston to move the truck, while a switch mechanism 4S is attached to the base 10 to regulate the extent of movement of the truck beneath the molding head.

In accordance with this invention, a laterally extending, elongated metal roller 50 is alxed to an axially extending shaft 52 having end journal portions rotatably mounted in a pair of pillow block bearings 54 supported on the side of the head l2 adjacent the sand chute 46. The shaft 52 is extended laterally at one end beyond the adjacent pillow block bearing and is provided with a sheave 56 for carrying a V-belt 58. A second electric motor 60 is mounted on the upper surface of the molding head 12 and rotates the shaft 62 through a suitable gear box 64. A larger sheave 66 is ailixed to the outer end of the shaft 62 and, along with sheave 56, carries the V-belt 5S. In this manner the motor 60 drives the roller at a suitable, relatively low speed in the direction indicated in FIGURE 3.

The roller consists of a hollow metal cylinder 68 having closed end walls which are rigidly attached to the rotatable shaft 52. As shown in FIGURE 3, a series of axially extending angle irons or cleats 70 are welded to the outer circumferential surface of the cylinder 68 and extend throughout its entire length. It is preferable to locate these angle irons suiliciently close together to cover most of the outer surface of the cylinder. I have found that l x l" x Mi" angle irons are highly satisfactory for use on rollers which are two or three feet in length and 10 to 12 inches in diameter. It will be noted that the metal roller 50 is mounted so that the cleats 70 barely clear the top surface of the ask 34, preferably only by about Mi inch, when the sand-filled ilask is moved into position beneath the roller.

A sand shield or delector 72 is attached to the same side ofthe molding head as the roller and extends downwardly over the upper half of the roller.

During operation of the molding machine, sand 74 from the sand chute 46 is deposited over the pattern 44 in the llask 34, which is supported on the truck 40 by the pattern plate 36. Sufficient sand is deposited over the pattern so that it normally extends eight to ten inches above the top of the flask. The pneumatic system within the base 10 then moves the truck in the direction of the molding head 12. As the flask passes beneath the powerdriven cleated roller Si), the roller rotates in a counterclockwise direction, as viewed in FIGURES 1 and 3, and packs excess sand tightly into the iiask above the pattern. This is accomplished because the motor 60 rotates the roller suiliciently rapidly to cause the tangential surface speed of cleat portion 70 of the roller to slightly exceed the linear speed of the mold ask 34. In this manner, the sand is compressed to a suiiicient extent to preclude the possibility of molten iron running out through the bottom of the mold when the molten casting metal is poured.

When the flask with its pre-packed molding sand is positioned directly under the molding head 12,'as shown by the broken lines in FIGURE l, air under pressure is conveyed through the piping 32 to the chamber .30 to cause the flexible diaphragm 22 to contact the sand and further pack it over the pattern 44. Next, the highpressure air is shut off, and the blower 28 is used to evacuate the chamber 30 to draw the diaphragm out of contact with thevmolding sand and up into the molding head. The truck 40 then moves the completed mold from beneath the molding head 12. The pneumatic piston'and cylinder combination 42 is next operated to strip the completed mold from the pattern 44. Cope and drag halves of the mold formed in this manner are then joined together, and molten casting metal is poured into the mold cavity.

When a conventional strike-off plate is employed with a diaphragm-type sand molding machine, such as the one hereinbefore described, the pressure of the diaphragm during the molding cycle'normally depresses the sand in the flask approximately three to tive inches below the top of the ask. Thus it will be seen that unless an exceptionally deep flask is used or the pattern is relatively fiat, the amount of sand between the pattern and the cavity created bythe diaphragm is very small. Consequently, during subsequent pouring `operations the pressure of the molten casting metal frequently will cause the metal to penetrate the resultant thin sand layer and run out through the bottom of the drag mold. On the other hand, when the power-driven, sand-packing roller is employed to pre-y compress the molding sand on top of the ask in the manner hereinbefore described, the metal runout problem is eliminated. The sand is packed so ltightly above the pattern thatithe subsequent application Vof compressed air to the diaphragm generally results in creating a cavity in the ask above the pattern which is only about one inch in depth. The additional three inches of -viirrnly packed sand provided around'the pattern effectively; prevent runouts. As indicated above, moreover, this prepacking of the sand also results in considerably lharder mold edges and superior mold definition.

Various modifications in the arrangement and details of theV specific embodiment described and shown herein will be apparent' to those skilled in the foundry art and are contemplated as within the scope of the present invention as defined in theappended claims.

I claim:

1. A sand molding apparatus comprising means for supporting a flask containing sand heaped above its upper its upper edges, an elongated roller supported adjacent said means, said roller having axially extending cleats affixed to its generallycylindri'cal outer surfaces, meansV for moving said sand-filled flask horizontally beneath said roller and into a position in which sand in said flask above said edges contacts said cleats on lower surfaces of said roller, lmeans for rotating said roller so that its cleats are moving in the same general direction as said flask when in contact with said sand, said roller being rotatable` at a rate suflicient to provide said cleats with a tangential speed exceeding the linear speed of the flask when said cleats are in contact with sand in said flask.

2. A foundry sand molding apparatus comprising a base, meansto support a flask containing molding sand heaped above its upper edges, a molding head supported above said base, said head having means to exert downward pressure on said sand in said flask, an externally cleated roller horizontally mounted adjacent one side of said head, means for moving said ilask successively to positions in contact with lower surfaces of said roller and beneath said head, and means for rotating said roller so that said lower surfaces are moving in the same general direction as said ask whenl contacting said sand, said roller being rotatable at a rate suicient to provide said surfaces with a tangential speed exceeding the linear speed of the flask when-said sand is being contacted'by said roller.

3. A foundry sand molding apparatus comprising a base, a molding head supported above said base, said head having a flexible diaphragm for exerting pressure on molding sand located beneath said head, a ask containing sand heapedv above its upper edges, a horizontally movable truck on said base supporting said ask, an elongated generally cylindrical roller supported in horizontal position by said head at one side thereof, said roller having axially extending cleats affixed to its outer surfaces, means for'moving said truck successively to a position in which sand in said ask 'above said upper edges is in contact with said cleats and to a position beneath said head, and means Vfor rotating said roller so that said cleats are moving in the same general direction as said flask when in contact with said sand, said roller being rotatable at a rate sufficient to provide said cleats with a tangential speed exceeding the linear speed fof the ask when sand in said flask is in contact withl said roller to thereby pre-pack the sand in the flask before .additionalpressure is exerted on said sand by said diaphragm.

4. A method of molding foundry sand which comprises depositing sand over a pattern located in a flask to a depth several inches above the upper edges ofV said flask, there-Y after moving said sand-filled flask so that cleats on outer surfaces of a horizontally disposed roller contact said sand above said upper edges, and rotating said roller at a rate sufficient so that the tangential speed of said cleats exceeds .fthe linear speed of said flask, said roller being rotated so-that said cleats in contact with said sand are moving in the same direction as said flask.

5 A method of molding foundry sand which comprises depositing sand over a pattern located in a ask -to a depth several inches above the upper edges of said flask, moving said sand-filled ask horizontally to aV position beneath a horizontally mounted, power-driven roller so that elongated cleats on outer surfaces of said roller contact said sand above said upper edges,-rotating said roller at a rate suicient to cause the tangential speed of said cleats to exceed the linear speed of said ask, said roller being rotated so that said cleats in contact with said sand move in the same direction as said flask, thereafter moving said ask beneath a molding head and subsequently exerting additional pressure with a diaphragm on the upper surface of the sand packed in said ask.

References Cited in the ile'of this patent UNITED STATES PATENTS 1,100,562 Heller June 16, 1914 1,184,356 Kramer May 23, 1916 2,353,207 Cohitaker July 11, 1944 2,852,820 Taccone Sept. 23, 1958 2,869,189 Prsig Jan. 20, 1959

Claims (1)

1. A SAND MOLDING APPARATUS COMPRISING MEANS FOR SUPPORTING A FLASK CONTAINING SAND HEAPED ABOVE ITS UPPER ITS UPPER EDGES, AN ELONGATED ROLLER SUPPORTED ADJACENT SAID MEANS, SAID ROLLER HAVING AXIALLY EXTENDING CLEATS AFFIXED TO ITS GENERALLY CYLINDRICAL OUTER SURFACES, MEANS FOR MOVING SAID SAND-FILLED FLASK HORIZONTALLY BENEATH SAID ROLLER AND INTO A POSITION IN WHICH SAND IN SAID FLASK ABOVE SAID EDGES CONTACTS SAID CLEATS ON LOWER SURFACES OF SAID ROLLER, MEANS FOR ROTATING SAID ROLLER SO THAT ITS CLEATS ARE MOVING IN THE SAME GENERAL DIRECTION AS SAID FLASK WHEN IN CONTACT WITH SAID SAND, SAID ROLLER BEING ROTATABLE AT A RATE SUFFICIENT TO PROVIDE SAID CLEATS WITH A TANGENTIAL SPEED EXCEEDING THE LINEAR SPEED OF THE FLASK WHEN SAID CLEATS ARE IN CONTACT WITH SAND IN SAID FLASK.

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