US3730250A

US3730250A - Method of making a sand mold

Info

Publication number: US3730250A
Application number: US00110654A
Authority: US
Inventors: H Fellows
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-01-09
Filing date: 1971-01-28
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

Bottomless cope and drag boxes mounted on a turntable are cleaned, assembled upon a pattern plate, turned on edge and clamped between closure platens and filled with molding sand. The platens are then advanced into the boxes to compress the sand against the patterns to form molds. Upon withdrawal of the platens, a sprue hole is made, the assembly is rotated to horizontal, and the boxes and contained molds are separated from the pattern plate, which is then withdrawn. After insertion of cores, if any, the boxes and molds are re-closed. An elevator rises through a withdrawal yoke into engagement with the mold whereupon a complementary platen opposing the elevator forces the sand mold downwardly from the boxes and into the plane of the yoke to the level of a withdrawal table onto which the yoke draws the mold, leaving the boxes empty for repetition of the process.

Description

United States Patent [191 Fellows METHOD OF MAKING A SAND MOLD [76] Inventor: Harrison E. Fellows, Clearwater Lake, Wis. 54518 [22] Filed: Jan. 28, 1971 [21] Appl. No.: 110,654

Related U.S.'Application Data [62] Division of Ser. No. 790,072, Jan. 9, 1969, Pat. No.

[56] References Cited UNITED STATES PATENTS 3,556,196 11/1971 Buhler "1 64/40 X. 3,229,336 l/1966 Hunter et al ..164/200 X 3,303,535 2/1967 Rearwin et al. ..l64/l72 3,433,285 3/1969 Fellows ..l64/200 X STATION I [111 3,730,250 [4 1 May 1,1973

Primary Examiner-J. Spencer Overholser Assistant Examiner-John E. Roethel Attorney-Wheeler, House & Wheeler 57 ABSTRACT Bottomless cope and drag boxes mounted on a tumtable are cleaned, assembled upon a pattern plate, turned on edge and clamped between closure platens and filled with molding sand. The platens are then advance d into the boxes to compress the sand against the patterns to form molds. Upon withdrawal of the platens, a sprue hole is made, the assembly is rotated to horizontal, and the boxes and contained molds are separated from the pattern plate, which is then withdrawn. After insertion of cores, if any, the boxes and molds are re-closed. An elevator rises through a withdrawal yoke into engagement with the mold whereupon a complementary platen opposing the elevator forces the sand mold downwardly from the boxes and into the plane of the yoke to the level of a withdrawal table onto which the yoke draws the mold, leaving the boxes empty for repetition of the process.

6 Claims, 25 Drawing Figures STAT \ON :1

STATmNm.

STATION 3! Patented May '1, 1973 7 Sheets-Sheet 1 H zofrliw Patented May 1, 1973 7 Sheets-Sheet 4.

iuvefl'roil Haze/501v: Fzuows 31 W, W, M1

Patented May 1, 1973 7 Sheets-Sheet 5 ATTOINEH Pgtented May 1, 1973 '7 Sheets-Sheet 6 @ALLMQA,

ATTORNEY METHOD OF MAKING A SAND MOLD This application is a division of Ser. No. 790,072, filed Jan. 9, I969, and now US. Pat. No. 3,589,431.

BACKGROUND OF INVENTION This application is a companion to my application Ser. No. 476,090, filed July 30, 1965 and now US. Pat. No. 3,433,285.

There are molding machines which produce a drag mold and then roll over to make a cope mold. The disadvantage of such devices lies in the fact that the drag mold is made against an unsupported pattern which will deflect under some conditions. It is also known to make both molds simultaneously by filling the form through the drag cavity from the side. In such devices of this character as I am acquainted with, the sand from an overhead magazine has to be forced through a bent pipe or conduit to enter the drag cavity in this manner and there is considerable friction and sometimes inadequate filling.

SUMMARY OF INVENTION The limited rotation of the mold boxes in the instant device presents the mold cavities simultaneously to separate filler spouts to receive sand directly from overhead magazine means of the type disclosed in my prior application above identified. The compression of the sand in the respective boxes also occurs simultaneously by platensoperating equally and oppositely to give uniform mold density in the respective boxes.

The boxes within which the molds are formed are pivotally attached to operating rams and slidably mounted in guides having trunnions carried by arms cantilevered from the indexing table. This arrangement permits the parts to be in the desired position, whether it be vertical or horizontal, at the respective stations, hydromotors preferably being used to effect the required bodily rotation on the trunnions.

For withdrawing the finished molds, a yoke embracing the molds travels across a withdrawal table. The molds are lowered to the level of the table on an elevator which rises through the yoke into mold engagement. When the elevator engages a mold from beneath, the mold is engaged from above by a platen complementary to the elevator and which descends to force the mold and elevator downwardly into the plane of the yoke at the level of the table.

Another feature of the invention is an arrangement whereby a three-way valve permits the application of pressure through the exhaust vents to facilitate the releasing of the sand molds from the boxes.

BRIEF DESCRIPTION OF DRAWINGS FIG. I is a diagrammatic plan view of parts of mold making equipment embodying the invention, the super structure being removed to expose most of the mechanism at the level indicated by the line 1-1 of FIG. 2.

FIG. 2 is a diagrammatic view taken in section on the line 2-2 of FIG. 1.

FIG. 3 is an enlarged detail view showing in side elevation the structure at Station II.

FIG. 4 is a view in vertical radial section through the mold filling structure in FIG. 3.

FIG. 6 is a fragmentary detail view on an enlarged scale taken in section through one of the vent fittings.

FIG. 7 is an enlarged fragmentary detail view in generally horizontal section through the parts of Station I.

FIG. 8 is a view in perspective fragmentarily illustrating diagrammatically and in mutually separated positions the mold boxes and associated parts.

FIGS. 9 to 25 are diagrammatic views showing procedural steps in which:

FIG. 9 shows air blast cleaning of sand from the mold boxes and patterns in preparation for re-use at Station I.

FIG. 10 shows the pattern plate advanced to position between the separated mold boxes at Station I.

FIG. 11 shows the mold boxes closed upon the pattern plate at Station I.

FIG. 12 shows the open ended mold boxes and pattern plate assembly rotated ninety degrees to receive the sand through the ends of the boxes at Station Il.

FIG. 13 shows the closure plates advancing to close.

the open ends of the mold boxes to provide closed chambers into which the sand can be blown at Stationv FIG. 14 shows the boxes closed and the sand being delivered into them about the pattern as at Station II.

FIG. 15 shows the sand within the boxes being subjected to compression against the pattern as at Station II.

force the pattern plate back to stored position at Station III.

FIG. 19 shows the pattern plate in stored position to i which it has been forced by III.

FIG. 20 shows placement of the cores in the sand mold at Station IV. I

FIG. 21 shows the two sections of the sand mold closed upon the core at Station IV.

the extended ram at Station FIG. 22 shows the closed molds and boxes above the path of the discharge yoke at Station V.

FIG. 23 shows the elevator raised through the discharge yoke into engagement with the lower section of the sand mold, the completed mold being held against the elevator by the opposed pressure plate at Station V.

FIG. 24 shows the upper pressure plate acting on the sand mold to push it from the boxes and to lower it on the elevator to the level of the discharge table and within the discharge yoke. 1

FIG. 25 shows the mold assembly advanced by the discharge yoke, pushing ahead of it across the discharge table the mold assemblies previously formed, and leaving the elevated, molding boxes empty for cleaning and re-use at Station I.

DESCRIPTION OF PREFERRED EMBODIMENT The number of working stations about the turntable 2 may be varied to suit the requirements. In the instant disclosure, there are five stations designated by Roman numerals I to V.

The annular turntable 2 has rollers 3 guiding it for rotation about a fixed post 4, the turntable being supported on rollers 5 which are in annular series beneath it (FIG. 2). Carried by the turntable is an annular indexing plate 6 shown in dotted lines in FIG. 1. This plate has shoulders at 7 corresponding in number to the number of stations and disposed to be engaged by the head 8 on ram 10 for the stepped indexing advance of the turntable through an angle equal to the angular spacing between stations. In accordance with conventional practice, stops 11 are desirably provided to assure accuracy of registration.

It is also desirable to provide an interlock to assure that the turntable will not be indexed until the operations at all of the several stations have been completed. If the indexing is controlled manually, this may involve no more than the provision of push buttons at the several stations which cause illumination of a succession of lights to tell the operator who controls ram 10 that all is in readiness for the indexing operation. If the operation is controlled mechanically, there can be signals given at the several stations which are connected in series in the circuit which energizes ram 10. Thus the relay circuit will be completed to energize ram 10 only when all of therelays are energized.

The turntable 2 is provided with pattern plate racks 12 corresponding in number to the number of stations. Each rack is equipped with rollers 14 upon which the respective pattern plates 16 may roll between an advanced position for use and a retracted position for storage. In the retracted position, each pattern plate is on the turntable 2. In the advanced position, the pattern plate has left the turntable under thrust of a ram as shown at Station I in FIG. 1. The pattern plates carry appropriate patterns 18.

Projecting radially from the turntable 2 are pairs of arms 20 for supporting between them pairs of

mold boxes

22, 24 which can be rotated in unison for ninety degrees, and can be brought together and separated as best shown in FIGS. 7 and 8. The arms 20 support bearings 26 for trunnions 28 which support guide channels 30, one of which is shown at the left in FIG. 8, it being understood that a similar arrangement is at the right. Reciprocable in each guide channel is a bearing block 32 which normally is in a position opposite the trunnion. This position is defined by impositive detents consisting of the springpressed balls 34 engaged in pockets 36 in the opposite faces of block 32. The block is elevated from this position by ram 80 at only one of the several stations and this ram controls its return movement.

Carried by each block 32 is a transverse angle bar 42 which supports rollers 44 providing a way along which shown in FIG. 8. A ram 52 connected with the box 24 has its plunger 54 engaged with block 32 for the raising and lowering of box 24. Similarly the ram 56 connected with box 22 has its plunger 58 connected with block 32 for the raising and lowering of box 22.

For bodily rotation of the mold box assembly, a motor 60, preferably a fluid pressure motor, has its output shaft 62 connected with trunnion 28 to turn the guide channel 30 through an arc of 90 to move the box assembly from the position shown at the left in FIG. 2 to the position shown at the right of FIG. 2 (and return). Flexible hose connections 64 are used as leads to the various rams and to the motor 60 and to the vent chambers 66 and 68 provided in the ends of

boxes

22 and 24. Through certain of the hose connections, air escaping from the boxes while the boxes are being filled with sand is carried to a three-way valve 70 having an atmospheric exhaust port 72. Later, when it is desired to discharge the molds from these boxes, the valve 70 connects the chambers 66 and 68 with fluid supply line 74.

At Station ll,

boxes

22 and 24 previously assembled on the pattern plate 16, are filled with sand. As already stated, these boxes are open ended. When assembled with the pattern plate 16, they are rotated to stand on edge as shown in FIGS. 3, 4 and 5 and the whole assembly is then elevated by the ram to engage the filling port 82 at the end of each box with the respective sand supply nozzle 84. Sand will be supplied through nozzles 84, preferably in accordance with the disclosure of the companion application above identified. However, before the sand can be admitted to the boxes,

the open ends of the boxes must be closed. The opposing ram heads 88 have spring biased seal frames 90 which engage the margins of the boxes about their open ends before the surfaces 92 of the heads 88 close the boxes. Sand is then injected under pressure as indicated by the arrows 94 in FIG. 4, the air within the boxes escaping through the chambers 66 and 68 and the hoses 64 to the three-way valve 70 and being discharged through the exhaust 72 to the atmosphere.

When the boxes are completely filled with sand about the pattern 18, the rams 88 are further advanced from the positions of FIG. 4 to the positions of FIG. 5 The seal frames 90 cannot partake of the advance, being engaged with the respective boxes. However, the ram faces 92 pass telescopically into the boxes as shown in FIG. 5 to compress the sand. When this has been accomplished, the rams 88 are retracted to the initial positions in which they are illustratedin FIG. 3 and the sand-filled

boxes

22 and 24 are lowered from the position of FIG. 3 to the position of FIG. 2. They are now free to rotate ninety degrees so that they will be horizontal as in FIG. 8 instead of upright as in FIGS. 2 to 5.

The sequence of operations is illustrated diagrammatically in FlGS. 9 to 25.

At Station I, the boxes and patterns are cleaned of sand from the previous operation. This may be done by any convenient means such as the air jets 96. The pattern plates 16 and the pattern mounted thereon are then slid forwardly on the supporting rolls above described by a ram 15 which moves the pattern plate from the storage rack 12 on the turntable to the rollers 44 on the arms 42 which are parallel to and interdisposed upwardly.

dotted lines in FIG. 10.

The open ended

boxes

22 and 24 are now closed upon the pattern plate 16, as shown in FIG. I 1.

The turntable then indexes to advance the closed assembly of FIG. 11 to Station II. Here the motor 60 is energized to rotate the box assembly from its initial horizontal position to the on-edge position shown in FIG. 12 so ports 82 for the filling of each box are Operation of ram 80 now lifts the assembly from the position of FIG. 13 to the position of FIG. 14 to engage the box sides about ports 82 with the filling nozzles 84.

Immediately the closure rams 88 move in to engage the seal rings 90 with the margins of the boxes and to dispose the closure surfaces 92 across the initially open endsof the boxes. With the parts in the position of FIG. 4, sand is injected through the nozzles 84 and the air displaced from the boxes escapes to atmosphere through the valve 70 as above described.

The boxes being completely filled with sand as shown in FIG. 14, the rams 88 are advanced further as indicated in FIG. 15 to compact the sand around the respective patterns 18. Rams 88 are then retracted out of the boxes and the elevator ram 80 is lowered to restore the box assembly to its original height. It is preferably at this point, with the boxes still on edge, that the sprue basin or opening 100 is formed in any desired manner (indicated diagrammatically by reamer 101). The motor 60 is then reversed to restore the boxes to their initial horizontal position as shown in FIG. 17. This occurs, desirably, at Station lll.

Still at Station III, the

rams

52 and 56 are actuated to.

I the

boxes

22 and 24 and to restore it to the storage rack on the turntable (FIG. 19).

The turntable now indexes to move the boxes and molds to Station IV and the cores 108, if any, are positioned in the openings 110 left by the patterns 18 (FIG. 20). This operation is usually manual. Still at Station IV, the box 24 is now engaged with box 22 to close the mold (FIG. 21).

The assembly of boxes and mold is still supported on the turntablearms 20 at a level higher than that of the discharge table 112. When the turntable has rotated to bring the assembly to Station V, a normally retracted withdrawal yoke 114 which is U-shaped in plan is advanced from the position of FIG. 22 to that of FIG. 23 where it is positioned to receive the finished sand molds. At this point, the table 116 of elevator ram 118 is raised through the yoke into engagement with the sand mold 120 which is in box 22. At the same time, a complementary ejector plate 122 of ram 126 moves down into engagement with the sand mold 128 which is in box 24. The movement of the ejector plate 122 continues, forcing downwardly the

molds

128 and 120 and the elevator table 116 until the table registers with the withdrawal table 112 as shown in FIG. 24. The completed mold is now in the plane of yoke 114. The

boxes

24 and 22 are empty. The discharge of the finished molds from the boxes may be facilitated by the use of the three-way valve '20 to connect the pressure line 74 through hoses 64 with the respective vent cham bus 66 and 68 (FIGS. 7and 4).

Still at Station V,'the yoke 114' is moved by its ram toward the left as viewed in FIGS. 24 and 25, thereby withdrawing the mold from table 116 of elevator 118 beneath the

boxes

22 and 24. Movement of the mold just finished in the direction of withdrawal across the table 112 propels in advance of it on said table the molds previously delivered to the table in the manner described (FIG. 25).

The next indexing movement of the turntable 2 restores the boxes which have been under discussion back to Station I in readinessfora repetition of the sequence. It will be understood that in each of the five selected points on the turntable which registers with the five stations above described, there is a similar series of boxes and similar control mechanism so that with each periodical indexing movement another mold is completed and withdrawn for the pouring of metal into its sprue opening.

If desired, the method herein disclosed may be practiced by replacing permanent boxes for flaskless molds with frames to receive tight fl'askswhich will produce tight flask molds. l l

The operation would stillinvolve the ninety degree rotation of the flask-carrying frames in exactly the manner in which the permanent boxes are rotated in the manufacture of flaskless molds. The operation will then be as follows:

At Station I tight flasks and pattern will be positioned, assembled and rotated ninety degrees. The operations at the other stations will be as described except at Station V the complete tight flask mold will be discharged instead of pushing out the flaskless mold as ports with the supply nozzles. At Station lll, sand will be injected thus making the mold exactly as above described. At-Station IV, the assembly will be rotated back ninety degrees and the cope moldwill be drawn and pushed down a conveyor to a remote closing station. At Station V, the drag mold will be lowered'from the pattern and pushed down a conveyorto the closing station, the pattern thereupon being transferred back to Station I. There can be any desired number of core setting stations to accommodate additional core setters when the core setting time exceeds the machine cycle time.

Obviously, from a method standpoint, the significant ninety degree rotation is exactly the same as above described and it serves the same purpose.

Iclaim:

1. A method of making a sand mold which comprises the steps of making an assembly of form boxes by superposing the form boxes on an interposed generally horizontal pattern plate, rotating the assembly to position the pattern plate in a generally vertically position, covering the open faces of the form box with platens constituting temporary faces therefor, propelling sand into the form box, compressing the sand in the form box to constitute a mold, withdrawing the platens and returning the assembly to a position with the pattern plate generally horizontal, and removing the pattern plate.

2. A method of making a sand mold, said method comprising the steps of making an assembly of form boxes and a pattern plate by superposing the form boxes upon an interposed pattern plate, the boxes having sand receiving openings in their ends and after the assembly is made the boxes are turned on end and the respective openings are registered with and engaged by filling nozzles through which the sand is introduced.

3. A method according to claim 2 in which the boxes have no faces opposed to the pattern'plate and are temporarily closed by platens fitting their respective margins at opposite sides of the pattern plate during the introduction of sand into the boxes, the said platens being thereafter advanced concurrently in opposite directions toward the pattern plate to compress the sand with which the boxes have been filled.

4. A method according to claim 3 in which the said platens are withdrawn from the boxes and the boxes and their sand mold contents are restored to horizontal and separated, the pattern plate being thereupon removed and the boxes and their sand mold contents are reassembled.

5. A method according to claim 4 including the further steps of confining the sand mold contents of the boxes between upper and lower platens and effecting relative movement between the boxes and the sand mold contents thus confined, thereby ejecting the sand mold contents from the boxes.

6. A method of making a mold including the step of making a box by making an assembly of two open form boxes upon a pattern plate in horizontal position and turning the assembly on end, and disposingthe box between platens providing temporary top and bottom for the box, the filling of the box with sand involving the introduction of sand independently into the respective form boxes at opposite sides of the pattern plate, the advance of the platens producing compressed sand molds in the respective form boxes, and removing the pattern plate and thereafter assembling compressed sand molds made in the form boxes, and removing the assembled compressed sand molds from the assembly of form boxes.

UNITED STATES PATENT oFFIc-E CERTIFICATE OF CORECTION I Patent No. 3,730,250 Dated May 1, 1975 Inventor(s) Harrison E. Fellows It is certified that error appears in the above-identified patent and that saidLetters Patent are'hereby corrected as shown below:

Column 1, line 7, after "No. 355,285" insert issued March 18, 1969 Column 1, line 55, insert pivotally between the words "trunnions" and "carried' Column 5, line. 35', insert roviding a way after Y "rollers; l t

Column 5, lines 6 8c 7, delete the entire sentence--- Ihe turntable then indexes to advance the closed assembly of Fig. 11 to Station II.

Column 5, line ll, after upwardly. insert the following sentence The turntable'then indexes to advance the closed assembly of Fig. ll to Station II.

Signed and sealed this 29th day of January 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents FORM P0-10 0 (10-69) I USCOMM-DC 6037B-P69 w 1 U.S. GOVERNMENT PRINTING OFFICE: IBIS 0-366-334.

Claims

3. A method according to claim 2 in which the boxes have no faces opposed to the pattern plate and are temporarily closed by platens fitting their respective margins at opposite sides of the pattern plate during the introduction of sand into the boxes, the said platens being thereafter advanced concurrently in opposite directions toward the pattern plate to compress the sand with which the boxes have been filled.

6. A method of making a mold including the step of making a box by making an assembly of two open form boxes upon a pattern plate in horizontal position and turning the assembly on end, and disposing the box between platens providing temporary top and bottom for the box, the filling of the box with sand involving the introduction of sand independently into the respective form boxes at opposite sides of the pattern plate, the advance of the platens producing compressed sand molds in the respective form boxes, and removing the pattern plate and thereafter assembling compressed sand molds made in the form boxes, and removing the assembled compressed sand molds from the assembly of form boxes.