Flaskless Molding Machine

Abstract

A flaskless molding machine is disclosed for producing continuous stacks of molds. The machine comprises four operating stations disposed on ninety degree spacing about its periphery. Two oppositely disposed stations are mold forming stations and the alternate two stations are the receiving ends of oppositely spaced mold decks upon which the completed molds are stacked. A body containing four mold forming chambers oscillates between two positions to place the respective chambers alternately in alignment with the mold forming stations and the ends of the mold decks where the operations are performed.

Description

BACKGROUND OF THE INVENTION

Flaskless molding machines are known in which sand molds are successively formed between opposed pattern boards by the application of pressure to sand blown into the cavity formed between the pattern boards and the formed molds then transferred to a mold deck where they are horizontally stacked. The molds are continuously advanced along the deck where pouring of molten metal occurs to form a casting, and thereafter the casting is cooled and broken from the mold. In machines of this type the molds are commonly formed by blowing sand between a stationary pattern board and one that is movable and thereafter squeezing the boards together to apply pressure for forming the molds. The formed mold is thereafter stripped from the flask head and transferred to the mold deck.

Because the pressure required to form the molds and, concomitantly, the unbalanced reaction forces produced in the machine parts are of a high order of magnitude, the parts must necessarily be constructed of heavy structural members that add to the equipment costs of the machine. Additionally, the productivity of prior art apparatus of the described type is limited by the fact that only one mold can be produced by the machine at a time thereby increasing the unit cost of the castings produced. Productivity of this machine is also adversely affected by the fact that castings of only a single configuration can be produced by machines of this type without having to change the pattern boards in the mold forming apparatus.

SUMMARY OF THE INVENTION

According to the invention there is provided a flaskless molding machine of the described type comprising four operating stations disposed on ninety degree spacing about its periphery. Two of the stations are oppositely disposed molding stations while the remaining two stations are transfer points for moving completed molds to a stacking deck. A body containing four integrally formed flask heads is centrally located between the operating stations and is adapted for oscillating movement between two positions. With the body in one position molds are produced within two of the flask heads at the respective mold forming stations and previously formed molds are transferred from the other two flask heads to the respective mold decks. The body is then rotated to its second position where molds are formed in the two empty flask heads while those containing formed molds are placed in alignment with the mold decks and the molds transferred thereto.

Because the mold forming stations in the present invention are oppositely spaced, the forces produced in the machine are oppositely directed and balanced thereby enabling them to be easily accommodated as tensile forces in the machine frame. This enables the machine to be constructed of lighter, less costly structural members. Additionally, because duplicate operations are performed concurrently, the productivity of the machine is considerably greater than that achieved in similar prior art apparatus.

Another important advantage of the invention is that castings of different configurations can be concurrently produced thereby giving the machine a degree of versatility that is lacking in similar apparatus heretofore known in the art.

Other objects and advantages of the present invention will become evident when the following description is read in conjunction with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric representation of a flaskless molding machine constructed according to the present invention;

FIG. 2 is a plan sectional view of the flaskless molding machine of FIG. 1; and

FIG. 3 is an elevational section taken along line 3-3 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A flaskless molding machine constructed according to the present invention is indicated generally as 10 in the drawings. It comprises a frame 12 about the periphery of which are located four operating stations disposed on 90.degree. spacing and indicated as A, B, C, and D, disposed on ninety degree spacing. As will be explained hereinafter, stations A and C are mold forming stations while stations B and D are those in which finished molds 14 containing casting cavities 16 produced at the forming stations are transferred to elongated stacking decks 18.

The frame 12 of the machine 10 includes a base plate 20 here shown as having a substantially circular peripheral edge and an elongated rectangular top plate 22 that is spacedly attached at its ends to the base plate by upstanding end plates 24. The top plate 22 mounts a pair of sand delivery apparatus indicated generally as 26, each being disposed adjacent the respective ends of the top plate and being operative at the respective mold forming stations A and C. The sand delivery apparatus 26, as is well known, each include a sand hopper 28 that connects with a blow chamber 30 through a gate valve 32. A discharge conduit 34, opening from the bottom of the blow chamber 30 passes through the top plate 22 for supplying sand to the mold forming chambers under the influence of air admitted through blow valve 36 as hereinafter more fully described.

The end plates 24 of the frame 12 each mount a cylinder 38 that forms part of the squeeze motor 39 of the molding machine. The cylinders 38, as shown, are oppositely directed and each contain a ram 40 at the end of which is attached a molding platen 42 adapted for reciprocable movement into and out of its molding forming position. The squeeze cylinders 38 are connected to a source (not shown) of high pressure operating fluid that is utilized to impart a squeezing force to the sand for forming the molds. Squeezing pressures of the order of 200,000 pounds are typical for this purpose.

Mounted within the frame 12 for horizontal pivotal movement is an integrally formed hollow body 44 of generally cruciform shape. The body 44 contains a hub portion 46 through which a vertical shaft 48 extends and is fixedly attached to the body. The opposite ends of the shaft 48 are received in bearings 50 that are fixedly mounted in the facing surfaces of the base plate 20 and top plate 22 of the frame. A second bearing 52, which is a thrust bearing of enlarged diameter, is positioned between the body 44 and base plate 20 in concentric relation to the shaft 48.

The body 44 is provided with four flask heads 54 that are disposed on ninety degree spacing and which extend outwardly from hub position 46. Each flask head 54 comprises a receptacle formed of substantially rectangularly disposed sides 56 that define the periphery of a mold forming chamber. The upper side of each flask head 54 contains an opening 57 to permit passage of molding sand from the discharge conduit 34 of the sand delivery apparatus 26. The radially inner end of the receptacle contains a shoulder surface 58 that opens to the axis of the body to permit passage of stripping motors 60. The stipping motors 60 are fluid motors comprising cylinders 62 the ends of which are fixedly attached to the four sides of a rectangular sleeve that is mounted on the shaft 48 between the hub portions 46 of the body. The cylinders 62 are connected to a source (not shown) of operating fluid to reciprocate rams 66 that are operative to eject finished molds from the receptacles to the stacking decks 18. Stripping pressures of the order of 20,000 pounds are normally sufficient for this purpose. The rams 66 each carry a stripping platen 68 that is attached for reciprocable movement within the flask heads 54. The stripping platens 68 are each of a size to abut the shoulder surface 58 in the respective receptacles when the former are in their withdrawn position. The rear surfaces of the stripping platen 68 contain a skirt 70, the surfaces of which engage raised surfaces 78 on the interior of the body 44 to guide the reciprocating movement of the platen 68.

An additional fluid motor, termed the oscillator motor 74, is connected between the frame 12 and the body 44 and operates to impart oscillating movement to the latter. The motor 78 comprises a cylinder 76 connected to a fluid pressure source (not shown) and is pin connected as at 77 to the frame 12. Its associated ram 78 is also pin connected, as at 80, to the surface of the body 44 whereby its reciprocation produces oscillating movement of the body through 90.degree..

The machine whose operation is described hereinafter employs dissimilar pattern boards 80a and 80b having raised hemispherical and conical forms respectively. This is to illustrate the ability of the machine to form molds for producing alternate castings having different configurations. It should be understood, however, that all of the pattern boards employed in the machine can, alternatively, be such as will produce castings of identical shape.

Pattern board 80a is attached to the molding platen 42 associated with the squeeze motor 39 at station A. Pattern board 80b is similarly attached to the molding platen 42 associated with the squeeze motor 39 at station C. The stripping platen 68 in the respective flask heads 54 attach pattern boards, indicated as 80a' and 80b', that compliment the pattern boards 80a and 80b respectively. With the body 44 positioned as shown in FIG. 2 the stripping platens 68 in the flask heads 54 disposed at stations C and D attach pattern boards 80a' while those at stations A and B attach pattern boards 80b'.

Starting with the body 44 in the position shown in FIG. 2, the gate valves 32 and blow valves 36 in both sand delivery apparatus 26 are actuated to admit sand to the chambers defined between the plates 42 and 68 in the two opposed flask heads 54 at stations A and C. After the chambers are filled with sand, the valves 32 and 36 are closed and operating fluid is admitted to the cylinders 38 of the squeeze motors 39 whereby pressure is applied to the sand by extension of the rams 40. The opposed pattern boards mounted on the platens 42 and 68 respectively are retained in compressed relation for a brief period (about 4 seconds) to form the respective molds. The rams 40 are then retracted and operating fluid is admitted to the cylinder 76 of the oscillator motor 74 to retract the ram 78 whereupon the body 44 is rotated ninety degrees counterclockwise. This places the flask heads 54 bearing the finished molds 14 at stations B and D adjacent the receiving ends of the mold stacking decks 18 and empty flask heads 54 at stations A and C. At this point, operating fluid is admitted to the cylinders 62 of the two opposed stripping motors 60 whereby the rams 66 are caused to be extended to eject the two finished molds from the flask heads 54 and to transfer them onto the decks 18. Substantially simultaneously with the actuation of the stripping motors 60 at stations B and D the sand delivery apparatus 26 at stations A and C are activated to admit sand to the mold chambers in the flask heads now disposed at these locations and the molding motors are actuated whereby the mold forming procedure is repeated. Thereafter oscillator motor 74 is activated to extend the ram 78 thereby rotating the body 44 clockwise through ninety degrees. This places the finished molds 14 at the transfer stations B and D and the empty flask heads 54 at the mold forming stations A and C.

The above described operation repeats continuously to produce a horizontal stack of formed molds 14 on each of the opposed stacking decks 18. With each activation of the stripping motors 60 the stack of molds 14 are advanced along the respective stacking decks 18. Means (not shown) for pouring molten metal into the molds 14, for cooling the castings, and for breaking the castings from the molds are disposed at spaced locations along the length of the decks thereby to provide a continuous casting operation.

The pouring of molten metal may or may not occur in timed sequence with the production of the molds. Under certain conditions it may be desirable. However under other conditions it may be more practical first to produce a stack of casting molds and thereafter pour the total number of mold cavities in this stack before the production of another stack of molten metal of molds is initiated.

It will be understood that various changes in the details, materials, and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention, may be made by its skill in the art within the principle and scope of the invention as expressed in the appended claims.

Claims

What is claimed is:

1. Apparatus for use in the production of casting molds in a flaskless molding process comprising:

a frame having a plurality of mold forming stations and a plurality of mold transfer stations alternately disposed about its periphery;

a flask head assembly pivotably mounted upon said frame for oscillation between two positions, said assembly having a plurality of flask heads arranged for operative disposition alternately between said mold forming stations and said mold transfer stations when said assembly is disposed in each of said positions;

said mold forming stations and said mold transfer stations each being arranged in groups consisting of two oppositely spaced stations;

fluid motor means operatively attached to said frame at each of said stations, said fluid motor means including molding motors at said mold forming stations and stripping motors at said stripping stations, the motors in each of the respective groups being arranged in oppositely facing relation; and

means for simultaneously actuating the fluid motors in each of the respective groups.

2. Apparatus according to claim 1 in which said flask head assembly comprises a body centrally disposed between said stations and containing a plurality of integrally formed flask heads, each defining a mold forming chamber; a pivot connection at the center of said body attaching the same to said frame; a stripping platen movably mounted in each of said flask heads; and said stripping motors being operatively connected to said stripping platens.

3. Apparatus according to claim 2 wherein said stripping motors connect between said pivot connection and said stripping platens.

4. Apparatus according to claim 2 wherein said molding motors each contain a movable molding platen and means for extending said molding platens into said flask heads when the same are operatively disposed at said mold forming stations.

5. Apparatus according to claim 4 wherein said frame comprises oppositely spaced, horizontally disposed top and bottom plates; means in said plates for attaching said pivot connection; upstanding end plates disposed at said mold forming stations and spacidly attaching said top and bottom plates; and means in said end plates for horizontally mounting said molding motors.

6. Apparatus according to claim 5 including means operatively mounted upon said frame for discharging sand into said flask heads when the same are disposed at said mold forming stations.

7. Apparatus according to claim 5 in which said frame includes one group each of said mold forming stations and said mold transfer stations and said body contains four flask heads circumferentially spaced for operative disposition with respect to the stations in said groups when said assembly is in each of its operating positions.

8. Apparatus according to claim 7 wherein said stations and said flask heads are disposed at right angles with respect to one another.

9. Apparatus according to claim 8 in which the stripping motors associated with the flask heads at said mold transfer station are arranged for simultaneous actuation with said molding motors.

10. Apparatus according to claim 9 including pattern boards attached to platens and wherein each of said molding platens attaches a pattern board carrying a pattern different from that on the pattern board attached to the stripping platen in the flask head with which it operates.