US1481320A

US1481320A - Molding appaeattts

Info

Publication number: US1481320A
Authority: US
Publication date: 1924-01-22
Anticipated expiration: 1941-01-22

Description

Jan. 22 1924. 1,481,320'

L. JoHNs'roN MOLDING APPARATUS Filed March 16. 1922 1 l Il:

ATTORNEYS Patented Jan. 22, 1924.

UNITED STATES LEONARD JOHNSTON, 0F SPRINGFIELD,

MASSACHUSETTS, ASSIGNOR TO SPRING- FIELD BRONZE COMPANY, INC., A CORPORATION 0F MASSACHUSETTS.

HOLDING APPARATUS.

Applicationled March 16, 1922.

T 0 all fw 7mm t may concern.

Be it known that I, LEONARD JOHNSTON, citizen of the United States, residing at Springfield, in the county of Hampden and State of Massachusetts, have invented new and useful Improvements in Molding Apparatus, of which the following is a speci.

fication.

This invention relates to improvements in molding apparatus and more particularly to means for use in compressin a mass of sand or like molding materia Within a flask and against a pattern so as to form a mold and for subsequently cooperating i with the flask to support the mold during the casting operation.

Sand molds are commonly made from a pattern with the aid of the usual two part melders flask consisting of a nowel and a cope.v .In accordance with a method heretofore more or less generally practised the cope is filled with sand and the pattern positioned therein so that at least half of its surface area is exposed above the level of the sand. rThe nowel is then placed upon the cope and filled with sand which is packed firmly therein either entirely by means of hand tools or with the aid of a molding machine.k The flask is then inverted to bring the cope uppermost and Aa gate is formed in the sand of the cope to enable the metal to be poured into the mold cavity. If poweris to be employed to assist in the packing of the sand in the. flask, the sand is usually Ypiled somewhat above the top of the flask and a flat board is laid on the sand, and forced downwardly by the plunger of the molding machine so that the surplus sand is pressed into the flask and compacted against the upwardly directed portions of the pattern. a peen hammer is then employed to ram the sand tightly against the sides of the flask so that it will stay in place when the flask is subsequently inverted. This tool is normally of such shape and so manipulated that a certain amount of lateral pressure is imparted thereby to the mass of sand tending to compact the sand against the sides Vor other portions of the pattern which may be so disposed as not to'receive the direct pressure of the molding machine plunger. When the board is used, as above described, to transmit downward pressure to the sand it is obvious that the degree of compression A suitable hand tool such as Serial No. 544,309.

of the sand will be determined by the proportional amount of the mass projecting above the top of the flask and inasmuch as there is no means for accurately gaging the amount of sand to be thus piled above the flask the degree of compression of the mass will vary more or less in makingfsuccessive molds.

One object of the present invention is to provide practical and reliable means for enabling all the necessary compression of the' sand and compacting of the same again-st` the pattern and against the sides of the flask to be accomplished at a single operation effected by power such as may be derived from the plunger of a molding machine.

Another object of the invention is to secure the desired compression of the sand more quickly and efficiently than heretofore and to insure the attainment of uniform results in successive compressing operations.

Vith the above objects in view, the invention contemplates the provision, for use in conjunction with a pattern and a-molders flask, of a pressure plate movable within the flask for compressing the sand, and constructed and arranged t0 exert a maximum amount of pressure adjacent the sides of the flask. In the illustrated embodiment of the invention, the pressure plate is provided adjacent its margin with a raised rib having an inwardly beveled face which is adapted to be forced into the sand adjacent the sides of the flask to exert an excess of pressure upon that portion of the sand and which has a tendency to displace the sand inwardly toward the pattern so asy to compact the same against the sides thereof. In using a pressure plate such as linst described the cope is filled with sand, the pattern is positioned` therein, and the nowel is then placed upon the cope and filled with sand as usual. Instead of heaping the sand above the flask and crowding the surplussand into the'mold as heretofore, however, the sand is levelled off flush with the top edge of the flask and the desired degree of compression is secured by depressing the pressure plate to a certain definite extent within the mold. In this way variable factors are eliminated and exactly the same quantity of sand is employed each time a mold is to be made in a flask of a particular size, so that uniform results are insured.

A further object of the invention is to los provide a sand mold having an improved structure adapted to facilitate the escape from the mold cavity of gases generated by the molten metal during the casting operation.

To this end a feature of the invention consists in the provision, in a sand mold of a plurality of spaced apart zones extending through the sand between the mold cavity and the exterior of the mold in which zones the sand is less densely compacted than in the intervening portions of the mold.

A still further object of the invention is to provide means whereby said zones of less densely compacted sand may be produced during the operation of compressing the sand by means of a pressure plate such as hereinbefore mentioned. f

In accordance with this object, a pressure plate is provided having a series of perforations into which the sand enters as the plate is depressed, so that little or no pressure is applied to the columns of sand immediately below said perforations. As a result the sand in these columns is less densely compacted than in the surrounding portions of the mass, and thus a plurality of zones of relatively low density extend transversely through the mass of sand to provide avenues of escape for the gases generated by the molten metal during the casting operation.

When the molten metal is poured into the mold cavity, its weight and nature is such that there is a. tendency for the loosely compacted sand in the above mentioned zones to be displaced to a certain extent through the perforations in the pressure plate by the weight of the metal. yAs a result, some of the molten metal may escape from the mold cavity and run downwardly through the sand at these points. To prevent such a. posibility it is preferred to construct the pressure plate in two superimposed sections or layers each of which is perforated, the perforations being so disposed that those of one section or layer are staggered with respect to those of the other layer. lith this construction there is no direct or straight passage leading outwardly from the interior of the flask and when the flask has been inverted preparatory to pouring the metal into the mold the solid portions of the outer plate section provide support for the loosely compacted columns of sand above the perforations in the inner section of the pressure plate. To permit free escape of the gases, the opposed surfaces of said sections are adapted in any suitable manner to permit indirect communication between the staggered perforations of the two plate sections.

plained in the following description and then particularly pointed out in the claims.

The various feature of the invention will be best understood from a description of the preferred embodiment thereof, illustrated in the accompanying drawings, in which:

Fig. 1 is a perspective sectional view of a pressure plate constructed in accordance with the present invention;

Fig. 2 1s a fragmentary side elevational view thereof;

Fig. 3 is a transverse sectional view of the pressure plate showing the same resting upon the sand at the top of a flask before the sand has been compressed thereby;

Fig. t is a bottom plan view, partly broken. away, of the pressure plate shown in Fi s. 1, 2 and 3;

ig. 5 is a` view, in vertical transverse section, of a two-part ask, showing a pattern supported in the sand within the flask, and showing also the pressure plate after pressure has been applied thereto and compress the sand; and

Fig. 6 is a view similar to Fig. 5 showing the mold inverted preparatory to the removal of the pattern therefrom.

Refering to Figs. 5 and 6 of the drawings, the usual two-part molders flask is therein sho-wn comprising the nowel or drag 8 and the scope 9, these parts being held in proper registry by means of suitably arranged dowels 10. The present invention resides to a large extent in the pressure plate which, as shown, comprises a rectangular outer section 12 preferably made of metal and rectangular inner section 13 preferably made of wood. The outer section of the pressure plate is large enough to overlap the sides of the flask and is provided, adjacent its margin, with a continuous rib or peen portion 14 which is adapted to fit within the sides of the upper portion of the flask. The lower face of the rib 14 is bevelled inwardly as shown at 15. The portion of the pressure plate section within the rib la is provided with a series of spaced apart perforations 16. The inner section 13 of the'pressure plate is shaped to fit loosely within the ri'b 14 although it may be secured thereto in any suitable manner and it is provided with a plurality of perforations 17 which are staggered relatively to the perforations 16 in the outer section of the pressure plate.

In making the mold, the practice yhereinbefore brie-fly outlined is carried out. In accorda-nce with this practice the cope 9 is first placed lowermost, the same being positioned upon the table of a moldin machine. The cope is then filled with san and the pattern 11 is pressed into the sand as shown in Fig. 5, the sand not being compressed around the pattern but serving only temporarily to support the same. The nowel is Llas then placed 'on the cope, filled withsandand levelled olf flush with the top edge thereof. The pressure plate, comprising the sections 12 and 13, is then placed upon the sand with the rib 14 registering with the space within inner walls of the flaskas shown in Fig. 3. Thehydraulic plunger 18 ofthe molding machine kis theny actuated to depress the pressure plate into theposition in which it appears in Fig. 5. By this single movement of the pressure plate, the sand'is compressed in the desired manner. The sandis Efirmly packed against the sides of the flaskby the action of the ribs 14, the bevelled or peened faces 15 of which servetodisplace the sand inwardly thereby tending to compact Vit against the sides and ends of the pattern. The inner plate section 13 compresses the rest of the sand except that in the columns directly beneaththe perforations 17 which columns are less densely compacted than the surrounding mass'and project upwardly into and substantially through said perforations as shown in F-ig. 5. `Thus, b-y the action of the pressure rplate alone, the sand is so compressed that it is firmly packed in the flask and tightly compacted against the portions of the pattern which project into the nowel. Furthermore, by reason of the presence of the perforations 17, the sand immediately beneath the same receives little if any pressure directly from the pressure plate, and consequently a series of Zones 20 of more or less looselycomp-acted sand are formed which extend from the mold cavity, and from the line of parting between the sand in the nowel andthe cope, upwardly to the perforations in the pressure plate section 13. The pressure ofthe plunger 18 is continued until the overlappingmargin of the platesection 12 engages the upperfedge of the nowel. It will thus be seen that there is no chance for variation in the amount of compresion of the sand in sucoeeding'compressing operations and thus all molds con structed with the aid of the same flask p-attern andv pressure :platewill be uniformly of the same characteristics.

After the sand has beenthus compressed bythe action ofthe pressure plate, the flask is removed from the molding machine and inverted as shown in Fig. 6. Thepressure lplate is left 1 in place andservesto support sand inthe nowel. The cope isnow upperf most and the sand therein may be compressed by ymeans of another pressure plate which may be similar inall respects to-that already described and may be 4actuated in the same manner. After rkthe sand in the cope has been properly compressed, the pressure plate is removed therefrom-and agate (not shown) is formedthereinleading-from the top surface thereof to the mold cavity' vto enable the metal to be poured therein. 7 The pattern is then 'removed and the mold is ready to lreceive the metal. The inlet end of the .gate `is preferably disposedclosely adjacent one of the sides ofthe flask. With this arrangement, the molds may conveniently be stacked lone above another with gatesof successive molds having their inlet endsat oppositesides of the stack and with alternate molds projecting beyond the stack at said opposite sides thereof exposing the gates of the several molds for kthe pouring operation.

lVhen a mold is ready for the performance ofthe casting operation, the nowel is supported by the pressure plate as shown in Figy6, said plate resting upon the floor lor upon another flask as the case may be. W hen the metal is poured into the mold, any tendency of the metal to displace the loosely compacted columns of sand in the Zones 20 will be obviated by means of the outer pressure plate section 12 which provides adequate supportfor said sand columns. When the metal is poured into the mold thegases generated readily pass outward through the low density zones 2O inthe sand. It will be seen that certain of the zones 2O terminate at the line of parting betweenithe masses of sand in the cope and the nowel and any gases which may find egress from the mold cavity along said parting line will eventually escape through said zones. The inner pressure plate section 13 being preferably of 'wood fits with sufficient looseness against the outer plate section 12 to insure that the gases whichpass through the Zones 2O will work their way between said inner and outer pressure plates and finally pass through theperforations 16 in the outer plate section 12. To enable the gases to escape freely into the latmosphere in case the outer pressure plate `section 12 rests upon `a smooth flat surface, thefouter face ofthe said plate iS provided with a series of shallow grooves 21 (Fig. 4) interconnecting adjacent perforations 16 and connecting the outermost rows of said perforations with the margin of said plate thereby affording outlet passages for -the gases.

'lhe outer section 12 of the pressure plate may be made without the flange which as shown in the drawing projects beyond the rib 14 to overlap the sides of the flask. In sucha case two or more cross beams may be ysecured to the unribbed face of the pressure plate, Lthese ribs vprojecting beyond opposite ledges of the plate to overlap the sides of the flask. Such a construction is advantageous inasmuch as .it enables the operator to hold the-flask lafter the same has been inverted lby grasping the edges of the pressure plate between` saidcross. beams )and thus to place the flaskupon the floor without liability of having hisfingers squeezed between thepressure plate and -the floor.

The invention has been herein shown and tft till

described in an embodiment at present preferred but it is to be understood that the invention is capable of being variously changed and modified without departing from the spirit thereof, and that the scope of the invention is defined by the appended claims rather than by tion. f

Claims:

l. In combination with a molders fiask, a pressure plate movable toward the bottom of the flask to compress the sand therein and having a raised peen portion thereon shaped to displace the sand inwardly toward the sides of a pattern within the flask as the plate is moved downwardly within the flask.

2. In combination with a molders fla-sk, a pressure plate for use in compressing the sand within the flask, said plate provided with means to displace the sand inwardly and having a plurality of perforations arranged therein to relieve the sand from the pressure of the plate' at spaced intervals thereby producing` Zones of reduced density in the mass of sand.

3. In combina-tion with a molders flask, a

pressure plate for use in compressing the sand within the fiask, said plate having a plurality of perforations arranged therein to provide avenues of escape for gases, and means for preventing the escape of sand through said perforations while permitting the escape therethrough of' the gases.

4. In combination with a molders flask, a pressure plate for use in compressing the sand within the fiask, said plate having a plurality of perforations arranged therein to relieve the sand from the pressure of the plate at spaced intervals thereby producing zones ot reduced density in the mass of sand, means for preventing the escape ot' sand through said perforations While permitting the escape therethrough of gases and a second plate overlying the first plate and having perlorations extending therethrough, said plates adapted to be relatively positioned with. the pert'oiations of one plater staggered with respect to the perforations of the other plate. i

5. In combination with a molders fiask, a pressure plate for use in compressing the sand within the fiask, said plate having a plurality of p'erforations arranged therein to relieve the sand fromA the pressure of the plate at spaced intervals thereby producing zones of reduced density in the mass of sand, a second plate overlying the first plate and having perforations extending therethrough, said plates having their opposed faces adapted to afford intercommunication between the perforations of said plates. y

6. In combination with a molders fiask, a pressure plate for use in compressing the sand within the fiask, said plate having a the foregoing descripl rib projecting from one face of the plate adjacent its margin for applying a greater amount oiz pressure to the sand than the rest of the plate and the portion of the plate within said'` rib being provided with a plurality of perforations to provide avenues of escape 'for gases, a second plate arranged face-to-'face with the ribbed plate inside of said rib and having a plurality of perforations extending therethrough and arranged instaggered relation to the perforations 'of the ribbed plate, the opposed surfaces of said plates being adapted to provide avenues of communication between adjacent staggered perforations to afford continuous outlet passages for gases.

7. In combination with a molders fiask, a pressure plate for use in compressing the sand within the flask, said plate yhaving a rib projecting from one face of the plate adjacent its margin for applying a greater amount of pressure to the sand than the rest of the plate and the portion of the plate within said rib being provided with a plurality of perforations, a second plate arranged face-to-face with the first plate and loosely fitting inside of said rib, the opposed faces of said plates together with the edge faces of the first plate being constructed and arranged to provide outlet passages leading from the interior of the mold to the exterior thereof thus providing avenues of escape for gases.

8. In combination with a molders fiask, a pressure plate for use in compressing the sand within the flask, said plate having a rib projecting from one face of the plate adjacentits margin for applying a greater amount of pressure to the sand than the rest of the plate and the portion ofthe plate within said rib being provided with a pluralitv of face-to-face with the first plate inside of said rib and having a plurality of perforations extending therethrough and arranged in staggered relation to the perforations of the ribbed plate to relievethe sand from the pressure of the plate at spaced intervals thereby producing Zones of reduced density in the mass of sand, said plates having their opposed surfaces adapted to provide avenues of communication-between adjacent staggered perforations to aflord continuous outlet passages for gases, and the outer face of the ribbed plate having a series of grooves interconnecting adjacent perforations and `connecting the outermost row's'of perforations with the margin of said plate thereby affording outlet passages for gases when the grooved face of' said plate rests upon a smooth fiat surface.

In testimony whereof I have affixed my signature.

LEONARD JOHNSTON.

perforations, a second plate arranged