US3121267A - Pattern-insert-receiving pocket and pattern-insert - Google Patents

Description

Feb. 18, 1964 G. E. SNOEYENBOS ETAL 3,121,267

PATTERN-INSERT-RECEIVING POCKET AND PATTERN-INSERT Filed Dec. 8, 1960 2 Sheets-Sheet 1 FIG. I

x 32 \PRESURE |7 7 VACUUM l7 FIG 2- 30 B /l2A I/IIBB I/IIS l I t\ |3 l I 5/ FIG.3 GORDON E. SNOE$ I I O g ATTORNEY GORDON E. SNOEYENBOS 26 DAVID R. SNOEYENBOS BY 27 27 MAHONEY, MILLEM-RAMB A M BY 4 M 18, 1964 a. E. SNOEYENBOS ETAL 3,121,257

PATTERN-INSERT-RECEIVING POCKET AND PATTERN-INSERT Filed Dec. 8, 1960 2 Sheets-Sheet 2 FIGS FIG. 6

l2 INVENTORS F" 7 ATTORNEY United States Patent 3,121,267 PATTERN JNEERT-RECEIWIN G POCKET AND PATTERN-INSERT Gordon E Snoeyenbos and David R. Snoeyenbos, Dayton, Ohio, assignors to Malleahle Research and Development Foundation, Dayton, Ohio, a corporation of Ohio Filed Dec. 8, 1969, Ser. No. 74,733 (Jlaims. (6i. 22F157) This invention relates to a pattern-insent-receiving pocket and pattern-insert. It has to do, more particularly, with a pocket in a metal stool or frame of a mold section for receiving an insert of a pattern to be used in the usual sand-molding processes.

At the present time in the foundry industry, it is customary to attempt to accurately form a pattern-insertreceiving pocket in a metal stool or frame. Usually this is attempted by machining the metal stool or frame to form the pocket. Obviously, it is expensive to machine the metal member with a pocket having the necessary accuracy to receive and precisely orient the pattern insert. Furthermore, with the necessary workable tolerances between the associated surfaces of the pocket and the insert, it is practically impossible to seal the joint between the pattern and the pocket. This joint must not be too tight or it would be impossible to remove the insert from the pocket. This is especially true if the insert and metal of the member in which the pocket is formed are of materials of different coeflicients of expansion. Furthermore, since the joint cannot be effectively sealed, the metal surfaces of the pocket will be galled during jolting and vibration eX- perienced in use by sand seeping into the joint and will, therefore, be difficult to remove.

According to the present invention, a roughly dimensioned cavity is formed in a metal mold stool or frame. This rough cavity will be larger than the insert to be inserted subsequently into the frame. in the cavity, a master insert is positioned and accurately located in spaced rela tionship thereto. Then the pocket is accurately formed by casting into the space between the cooperating surfaces of the rough cavity and the master, a suitable elastomer which will set or harden. After the elastomer does set or harden, the master will be removed and the elastomer material will remain in the metal member and will provide an accurately dimensioned pocket for receiving the pro duction pattern insert. The pocket will, therefore, have dimensionally controlled insert-contacting surfaces and these surfaces will be of a non-galling resilient nature. It is preferred that the border or peripheral surfaces of the pocket which are adapted to contact the peripheral edge of the insert be provided with an inwardly-extending 'exible or compressible sealing rib. The rib, when compressed by insertion of the insert, will provide an effective seal at the joint between the insent edge and the surrount ing wall of the pocket so as to prevent the entrance of sand, etc. into the joint. The rib also serves as a centering means for the insert in the pocket and makes it possile to have workable tolerances between the insert and the pocket and still obtain proper orientation of the insert in the pocket. It is also preferred that the elastomer material oi the pocket provide an integral outer wear strip or flange which has an outer surface or 13.66 for engagement by the edge of a cooperating mold flask to reduce wear or gelling at the engaging portions of the flask and the mold section.

This arrangement not only results in the advantages indicated above but provides a system that allows rapid change of pattern inserts without removing bolts or other mechanical hold-downs. The seal between the insert and pocket is primarily intended to allow pulling the insert into position and holding it in position as long as desired ice by the application of vacuum. Conversely, application of pressure to the shape between the pattern insert and the pattern insert receiving pocket will eject the insert far enough to allow easy removal from the cavity.

This invention is illustrated in the accompanying drawin gs wherein:

FlGURE 1 is a longitudinal sectional view showing a mold member having a pocket produced according to this invention in which a pattern insert is disposed according to this invention.

FIGURE 2 is a longitudinal sectional view showing the initial step in forming the pocket in the mold member by providing a rough cavity therein.

FIGURE 3 is a longitudinal sectional view showing a master to be inserted in the rough cavity of FIGURE 2.

FIGURE 4 is a longitudinal sectional view showing the master positioned in the cavity and located therein to provide a space in which the elastomer pocket-forming material is to be cast.

FIGURE 5 is a view similar to FIGURE 4 but showing the elastomer material cast in the cavity.

FIGURE 6 is a longitudinal sectional View showing the master removed to expose the accurately-formed pocket.

FIGURE 7 is a longitudinal sectional view showing the pattern insert to be inserted into the pocket of FIGURE 6 as shown in FIGURE 1.

With reference to the drawings, we have illustrated in FIGURE 1 the mold sect-ion it? having a pocket 11 formed therein receiving a pattern insert 12 according to this invention.

According to this invention, the mold section 10, such as a stool or frame, is first produced in a suitable manner as by casting from metal. This mold section, as shown in FIGURE 2, has a rough cavity llA formed therein and this cavity will be larger in all directions than the final pattern-receiving pocket 11 to be formed therein and which is shown FIGURE 1. i

A master insert 323A which will have dimensions and surfaces similar to the pattern insert 12 will be provided and will be positioned in the cavity MA, as shown in FlGURE 4, in centered relationship to the cavity 11A. In actual practice, the surfaces of the master insert will be spaced approximately A from the adjacent surfaces of the cavity. it will be noted that the master 12A has a supporting flange 13 which will rest on the flange 14 of the mold section li and has a depending portion 15 which extends into the cavity 11A. Centering of the master insert 12A in the cavity 11A can be accomplished in various ways as by having holes 16 in the flange 13 which will cooperate wi h the upstanding pins 17 on the mold section Centering of the master insert 12A in the cavity 11A will produce a continuous space or void 18 between the edge of the depending portion 15 of the master 12A and the associated surrounding peripheral wall of the cavity HA and between the inner wall surface or bottom surface of the master and the bottom of the cavity 11A. Also, it will be noted that the outer face of the mold section 19 is recessed at 19 to provide a void or space 18A at the inner surface of the flange 13 which is a continuation of the void 18.

The communicating spaces or voids 18 and 18A are filled with an elastomer material which may be suitably poured or forced thereinto through suitable gate openings in the master 12A. This material is preferably urethane in the form of polyurethane which is poured as a liquid into the voids and is allowed to set or harden. Instead of injecting through holes in the master 12A, the polyurethane may be injected through holes in the section it Also, it could merely be poured in the cavity 11A and the master 12A could then be inserted displacing excess polyurethane through suitable holes in the members It) or 12A, or both. Other materials such as soft polyamides, polysulfides, elasticized epoxies, conventional rubber and silicone rubbers may be employed as the elastomer. When the elastomer material hardens and forms the solidified liner or pocket material as shown in FIGURE 5, the master insert 12A is removed. This will leave the pocket 11 accurately formed and located in the mold section 10. It will, as shown, have side or edge walls 21, a bottom or inner wall 22, and an outer peripheral flange 23 all integrally joined, as shown in FIGURE 6. However, the essential feature of this invention is the use of the elastomer to contact and to locate and seal the pattern insert in the pocket. Whether or not the bottom of the cavity is covered with an elastomer or whether or not the flask wear strip is produced as part of the elastomer is dictated by other considerations relative to the particular application, although each of these latter features is important in certain applications. Thus, it is preferred but not necessary to cast the elastomer bottom and wear strip at the same time as the peripheral locating and sealing wall but not essential.

Preferably, the depending portion 15 of the master insert 12A has a continuous groove 24 formed in its edge surface 26A. This will produce an inwardly extending sealing rib 25 on the side wall 21 of the pocket 11.

The pattern insert 12 will be of the same shape and close to the same size or slightly smaller than the master 12A except that it will have a draft 27 on its peripheral edge 26 and will not carry a flange like the flange 13 of the master. Therefore, as it is inserted into the pocket 11, the tapered or draft surface 27 will wedge against and compress the sealing rib 25.

When a flask, indicated at 29 in FIGURE 1, is positioned on the mold section 10, its edge will rest on the upper surface of the flange 23.

It will be apparent that the pattern insert 12 will fit tightly in the pocket 11 and will be accurately centered therein. The elastomer lining for the pocket provides non-galling material in surrounding relationship to the pocket. The compressible rib on the lining provides both centering and sealing means for the pattern insert in the pocket. It will be possible with this arrangement to provide an accurate pocket but there can still be workable tolerances between the peripheral edge of the pattern insert and the surrounding peripheral wall of the pocket due to the compressible sealing rib. This Will provide for ease of insertion and removal of the pattern insert.

One of the prime objectives of this invention is to provide a system that allows rapid change of pattern inserts without removing bolts or other mechanical holddowns. The seal between the insert and the pocket is primarily intended to allow pulling the insert into position and holding it in position as long as is desired by the application of vacuum, through the wall of the pocket by well understood means. Tests indicate that comparatively low vacuums admitted to the cavity at a lower corner very adequately clamp the patterns in position and that applying a positive pressure in the same manner removes them from the pocket. This allows eX- ceedingly fast pattern changes; and by eliminating the usual cap screw hold-down device, allows complete freedom for positioning the patterns on the pattern insert. As illustrative, for example, such an arrangement is diagrammed in FIGS. 1 and 2 (although not shown in the other figures) as including a bore 30 communicating between pocket 11 and the outside of stool or flask 1i and diagrammed as being connected to a conduit 31, and a two-way valve 32 for selecting between a source of vacuum at 33 and a source of air pressure at 34, as a means for providing the disclosed vacuum hold-down effective upon pattern insert 12 and, selectively, the pressure dislodgment thereof for facilitating change of pattern inserts.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Having thus described this invention, what is claimed 1. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a substantially flat pattern stool for receiving a foundry mold flask thereon in which said sand mold is formed, and an insert-receiving cavity in said stool for engaging a pattern insert therein, a separate and replaceable pattern insert carrying on the upper surface thereof said pattern of said article on which said sand mold is to be formed in said flask as positioned on said stool, said pattern insert being dimensioned for interfitting engagement in said cavity in said stool and extending throughout substantially the entire area thereof within said flask, a resilient elastomeric sealing and cushioning layer around and between said cavity and said pattern insert as disposed therein for sealing engagement between the sides of said cavity and said insert maintaining said insert positioned in said cavity and preventing introduction of molding sand into said cavity around said insert.

2. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a substantially flat pattern stool for receiving a foundry mold flask thereon in which said sand mold is formed, and an insert-receiving cavity in said stool for engaging a pattern insert therein, a separate and replaceable pattern insert carrying on the upper surface thereof said pattern of said article on which said sand mold is to be formed in said flask as positioned on said stool, said pattern insert being dimensioned for interfltting engagement in said cavity in said stool, a resilient elastomeric sealing and cushioning layer around and between said cavity and said pattern insert as disposed therein for sealing engagement between the sides of said cavity and said insert maintaining said insert positioned in said cavity and preventing introduction of molding sand into said cavity around said insert, said sealing and cushioning layer being a-flixed to the side walls of said cavity and including a peripheral sealing head for engaging said pattern insert.

3. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a substantially flat pattern stool for receiving a foundry mold flask thereon in which said sand mold is formed, and an insert-receiving cavity in said stool for engaging a pattern insert therein, a separate and replaceable pattern insert carrying on the upper surface thereof said pattern of said article on which said sand mold is to be formed in said flask as positioned on said stool, said pattern insert being dimensioned for interfitting engagement in said cavity in said stool, a resilient elastomer ic sealing and cushioning layer around and between said cavity and said pattern insert as disposed therein for sealing engagement between the sides of said cavity and said insert maintaining said insert positioned in said cavity and preventing introduction of molding sand into said cavity around said insert, said sealing and cushioning layer being aflixed to the side walls of said cavity and including a peripheral sealing head for engaging said pattern insert, and means for maintaining a partial vacuum in said cavity and beneath said pattern insert for maintaining said insert firmly engaged in said cavity during said forming of said sand mold thereon.

4. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a substantially flat pattern stool for receiving a foundry mold flask thereon in which said sand mold is formed, and an insert-receiving cavity in said stool for engaging a pattern insert therein, a separate and replaceable pattern insert carrying on the upper surface thereof said pattern of said article on which said sand mold is to be formed in said flask as positioned on said stool, said pattern insert being dimensioned for interfitting engagement in said cavity in said stool, a resilient el-astomeric sealing and cushioning layer around and between said cavity and said pattern insert as disposed therein for sealing engagement between the sides of said cavity and said insert maintaining said insert positioned in said cavity and preventing introduction of molding sand into said cavity around said insert, and an additional resilient cushioning member on the top surface of said stool and underlying said flask as positioned thereon for sealing and cushioning the juncture of said flask and said stool against the abrasive leakage of sand thereto during said forming of said mold.

5. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a substantially flat pattern stool for receiving a foundry mold flask thereon in which said sand mold is formed, and an insert-receiving cavity in said stool for engaging a pattern insert therein, a separate and replaceable pattern insert carrying on the upper surface thereof said pattern of said article on which said sand mold is to be formed in said flask as positioned on said stool, said pattern insert being dimensioned for interfitting engagement in said cavity in said stool, a resilient elastomeric sealing and cushioning layer around and between said cavity and said pattern insert as disposed therein for sealing engagement between the sides of said cavity and said insert maintaining said insert positioned in said cavity and preventing introduction of molding sand into said cavity around said insert, said sealing and cushioning layer being aflixed to the side Walls of said cavity and including a peripheral sealing bead for engaging said pattern insert, and an additional resilient cushioning member in the top surface of said stool and underlying said flask as positioned thereon for sealing and cushioning the juncture of said flask and said stool against the abrasive leakage of sand thereto during said forming of said mold.

6. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a generally flat and horizontal pattern stool for receiving a foundry mold flask thereon during said forming of said sand mold in said flask, a pattern-receiving cavity in said stool for receiving a removable insert having said pattern theron and extending throughout substantially the entire area of said stool within said flask, said cavity having a cross-sectional dimension slightly greater than that of said pattern insert and a depth at least as great as the thickness of said pattern insert, and a resilient plastic sealing and cushioning layer around and between said pattern insert and said cavity as said insert is received in said cavity for tight sealing engagement between said insert and said cavity preventing introduction of molding sand therebetween during formation of said mold.

7. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a generally flat and horizontal pattern stool for receiving a foundary mold flask thereon during said forming of said sand mold in said flask, a patternreceiving cavity in said stool for receiving a removable insert having said pattern thereon, a resilient plastic sealing and cushioning layer around and between said pattern insert and said cavity as said insert is received in said cavity for tight sealing engagement between said insert and said cavity preventing introduction of molding sand therebetween during formation of said mold, and said sealing and cushioning layer being aifiXed to the side walls of said cavity and including a peripheral sealing bead for engaging said pattern insert, a portion of said sealing and cushioning layer extending over the top surface of said stool and underlying said flask as positioned on said stool.

8. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a generally flat and horizontal pattern stool for receiving a foundry rnold flask thereon during said forming of said sand mold in said flask, a patternreceiving cavity in said stool for receiving a removable insert having said pattern thereon, a resilient plastic sealing and cushioning layer around and between said pattern insert and said cavity as said insert is received in said cavity for tight sealing engagement between said insert and said cavity preventing introduction of molding sand therebetween during formation of said mold, and pneumatic means for maintaining a negative pressure in said cavity and beneath said sealing layer for holding said pattern insert into said cavity.

9. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a generally flat and horizontal pattern stool for receiving a foundry mold flask thereon during said forming of said sand mold in said flask, a patternreceiving cavity in said stool for receiving a removable insert having said pattern thereon, a resilient plastic sealing and cushioning layer around and between said pattern insert and said cavity as said insert is received in said cavity for tight sealing engagement between said insert and said cavity preventing introduction of molding sand therebetween during formation of said mold, and means for interjecting air pressure beneath said pattern insert in said cavity for dislodging said pattern insert for the removal thereof after forming said mold.

10. In mold making apparatus of the character described for forming foundry sand molds on a pattern of the article to be molded therein, the combination which comprises a generally flat and horizontal pattern stool for receiving a foundry mold flask thereon during said forming of said sand mold in said flask, a patternreceiving cavity in said stool for receiving a removable insert carrying said pattern thereon, a resilient plastic sealing and cushioning layer around and between said pattern insert and said cavity as said insert is received in said cavity for tight sealing engagement between said insert and said cavity preventing introduction of molding sand therebetween during formation of said mold, said sealing and cushioning layer being affixe'd to the side walls of said cavity and including a peripheral sealing head for engaging said pattern insert, a portion of said sealing and cushioning layer extending over the top surface of said stool and underlying said flask as positioned on said stool, and pneumatic means for maintaining a negative pressure in said cavity and beneath said sealing layer for holding said pattern insert into said cavity.

References Cited in the file of this patent UNITED STATES PATnNTS 2,933,786 Peterson Apr. 26, 1960 2,931,081 Dunlop Apr. 5, 1960 2,947,046 Wiedrnann Aug. 2, 1960 2,967,756 Mazzucchelli et a1 Jan. 10, 1961 2,970,352 Halgren et al Feb. 7, 1961

Claims (2)

1. IN MOLD MAKING APPARATUS OF THE CHARACTER DESCRIBED FOR FORMING FOUNDRY SAND MOLDS ON A PATTERN OF THE ARTICLE TO BE MOLDED THEREIN, THE COMBINATION WHICH COMPRISES A SUBSTANTIALLY FLAT PATTERN STOOL FOR RECEIVING A FOUNDRY MOLD FLASK THEREON IN WHICH SAID SAND MOLD IS FORMED, AND AN INSERT-RECEIVING CAVITY IN SAID STOOL FOR ENGAGING A PATTERN INSERT THEREIN, A SEPARATE AND REPLACEABLE PATTERN INSERT CARRYING ON THE UPPER SURFACE THEREOF SAID PATTERN OF SAID ARTICLE ON WHICH SAID SAND MOLD IS TO BE FORMED IN SAID FLASK AS POSITIONED ON SAID STOOL, SAID PATTERN INSERT BEING DIMENSIONED FOR INTERFITTING ENGAGEMENT IN SAID CAVITY IN SAID STOOL AND EXTENDING THROUGHOUT SUBSTANTIALLY THE ENTIRE AREA THEREOF WITHIN SAID FLASK, A RESILIENT ELASTOMERIC SEALING AND CUSHIONING LAYER AROUND AND BETWEEN SAID CAVITY AND SAID PATTERN INSERT AS DISPOSED THEREIN FOR SEALING ENGAGEMENT BETWEEN THE SIDES OF SAID CAVITY AND SAID INSERT MAINTAINING SAID INSERT POSITIONED IN SAID CAVITY AND PREVENTING INTRODUCTION OF MOLDING SAND INTO SAID CAVITY AROUND SAID INSERT.

8. IN MOLD MAKING APPARATUS OF THE CHARACTER DESCRIBED FOR FORMING FOUNDRY SAND MOLDS ON A PATTERN OF THE ARTICLE TO BE MOLDED THEREIN, THE COMBINATION WHICH COMPRISES A GENERALLY FLAT AND HORIZONTAL PATTERN STOOL FOR RECEIVING A FOUNDRY MOLD FLASK THEREON DURING SAID FORMING OF SAID SAND MOLD IN SAID FLASK, A PATTERNRECEIVING CAVITY IN SAID STOOL FOR RECEIVING A REMOVABLE INSERT HAVING SAID PATTERN THEREON, A RESILIENT PLASTIC SEALING AND CUSHIONING LAYER AROUND AND BETWEEN SAID PATTERN INSERT AND SAID CAVITY AS SAID INSERT IS RECEIVED IN SAID CAVITY FOR TIGHT SEALING ENGAGEMENT BETWEEN SAID INSERT AND SAID CAVITY PREVENTING INTRODUCTION OF MOLDING SAND THEREBETWEEN DURING FORMATION OF SAID MOLD, AND PNEUMATIC MEANS FOR MAINTAINING A NEGATIVE PRESSURE IN SAID CAVITY AND BENEATH SAID SEALING LAYER FOR HOLDING SAID PATTERN INSERT INTO SAID CAVITY.

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