US3156958A

US3156958A - Foundry molding machine

Info

Publication number: US3156958A
Authority: US
Publication date: 1964-11-17
Anticipated expiration: 1981-11-17

Description

Nov. 17, 1964 L. F. MILLER ETAL FOUNDRY MOLDING MACHINE 2 Sheets-Sheet 1 Filed July 9, 1962 FIG I FIG 2 INVENTOR.

LEON F.' MILLER 8 ROBERT W. ELLMS OherImIIIIIIwIL IlomMIq FIG 3 ATTORNEYS 1964 F. MILLER ETAL 3,156,953

FOUNDRY MOLDING MACHINE Filed July 9, 1962 2 Sheets-Sheet 2 FIG4 INVEN TOR. LEON F. MILLER 8 y ROBERT W. ELLMS vwmmuww y FIG 6 ATTORNEYS United States Patent This invention relates generally, as indicated, to a foundry molding machineand more. particularly, to certain improvements in a squeeze head for a foundry molding machine adapted to produce rapidly foundry molds of uniform desired hardness.

In the copending application of Edmond K. Hatch and Leon F. Miller, Serial No. 127,616, entitled Squeeze Molding Machine, filed July 28, 1961, there is disclosed a foundry molding machine having a diaphragm squeeze head which has been found to be particularly suitable for exerting uniform squeezing pressure on said molds in high speed automatic sand molding operations and which has proven quite durable in spite of the frequency of use and high pressures involved.

With diaphragm foundry molding machine squeeze heads, it is dir-lcult to maintain a uniform high degree of pressure over the entire upper surface of a sand mold especially when the amount of sand within such mold may vary from one cycle of operation of the machine to the next. If the diaphragm over a high point of the pattern should contact a solid inflexible back-up as the result of insufflcient sand being within the mold, considerable damage may result to the pattern and, of course, an improper mold will be formed. Moreover, the pres sure exerted by the diaphragm upon the sand will not then be distributed uniformly over the entire top of the sand mold.

It is accordingly a principal object of the present invention to provide a squeeze head for a foundry molding machine which will exert a uniform high degree of pressure on the sand mold regardless of variations in the amount of sand employed.

A further principal object is the provision of a squeeze head for a foundry molding machine having a flexible sand engaging surface provided with a laterally displaceable yet incompressible safety back-up.

Yet another principal object is the provision of a squeeze head for a foundry molding machine utilizing both a compressible and incompressible fluid.

A yet further object is the provision of a diaphragm squeeze head for a foundry molding machine employing a relatively small volume of compressible fluid and a separate back-up body of displaceable yet incompressible fluid.

Yet another object is the provision of a squeeze head for foundry molding machine which will exert a uniform high degree of pressure on the order of in excess of 200 pounds per square inch on the surfaces of relatively large sand molds.

()ther objects and advantages of the present invention will become apparent as the following description proceeds. a

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

in said annexed drawings:

FIG. 1 is a vertical section of a squeeze head in accord ance with the present invention shown above a sand filled flask prior to the compaction of sand therein;

Patented Nov. 1?, i964 FIG. 2 is a vertical section similar to FIG. 1 showing the relative position ofthe squeeze head and flask during the final stages of thesqueezing operation;

FIG. 3 is asitnilar vertical section showing the squeeze head and flask separated after the squeezing operation;

FIG. 4is a top, plan view of another form of squeeze head in accordane with the present invention;

FIG. 5 is a vertical section ofsuch squeeze head shown in sandsqueezing position taken substantially on the line 5 of FIG. 4; and,

FIG. 6 is a vertical section illustrating the manner in which the various chambers of the squeeze head are filled with the respective. fluids Referring now to the annexed drawings and more particularly to the embodiment of the invention shown in FIGS. 1 through 3, it will be seen that the squeeze head shown generally at 1 is employed with conventional foundry sand molding apparatus such as the flask 2, pat tern plate 3, and pattern 4 supported on such pattern plate within the confines of the flask. In conventional foundry practice, the flask 2 is filled with a molding sand S and the squeeze head and flask are then positioned in approximately. the relative positions shown in FIG. 1 either by laterally moving the flask after thus filled with sand to a position beneaththe squeeze head 1 or by shifting the squeeze head over the sandfilled flask. When the squeeze head and sand filled flask are thus vertically aligned as shown, they are moved relatively to each other to cause the squeeze head to engage the upper surface 5 of the sand within the flask to compress such sand against the pattern 4. When the sand has been compressed to the desired pressure by such relative movement as seen in FIG. 2, the head and flask will be moved apart to the FIG. 3 position and the flask containing the now compressed sand will generally be shuttled from the machine to have the pattern drawn therefrom. The squeeze head of the present invention may be employed, for example,

with a machine of the type set forth in the disclosure of the aforementioned Hatch et al. application, Serial No. 127,616 entitled Squeeze Molding Machine wherein the pattern plate 3 is positioned on a vertically movable table adapted to elevate the pattern and flask filled with sand against a relatively fixed squeeze head. The squeeze cylinders supporting the table and, of course, the pattern plate then provide the squeeze pressure. It will also be understood that the squeeze head may be mounted for vertical movement by overhead squeeze cylinders such as those shown in the copending applica ion of Edmond K. Hatch and Leon F; Miller, Serial No. 133,700, entitled Gverhead Squeeze'Molding Machine, filed August 24, 1961. In machines of this type, the flask containing the sand will be generally fixed relative'to the vertically movable head supported by overhead squeeze piston-cylinder assemblies. the flask and head, usually by high pressure hydraulic piston-cylinder assemblies, is all that is required for the squeeze head to exert the desired pressure upon the sand within the flask, squeezing the same to provide a sand mold of the desired uniform hardness. The flask, pattern plate, and pattern, of course, form no part of the present invention.

The squeeze head 1 comprises a downwardly opening cavity forming a chamber having a lower or bottom flexible sand engaging wall in the form of two juxtaposed relatively

thick diaphragm members

7 and 8, These diaphragm members extend across the bottom of the chamher or cavity and are held to the peripheral side walls 9 of such chamber by elongated screws or the like it passing through a peripheral clamping ring 11. Such fastoners It) also pass through a further clamping ring 12 In any event, relativevertical movement of i and 8 and, of course, on the sand S will increase.

in their unsupported position will bulge downwardly as indicated below the plane of their peripheral edges secured to the cavity. The clamping ring 12 may be held to the sides 9 of the chamber or cavity by similar fasteners indicated at 14. The top wall of the chamber is formed by the plate 15 which may be welded or otherwise suitably secured to the peripheral downwardly projecting sides 9. Back-up plates 16 may be secured to the top of the top plate 15 to rigidity the same and to facilitate the attachment of the head to the head of a foundry molding machine frame or the like.

The intermediate diaphragm 13 held by the clamping plate 12 then serves to compartment the chamber in the squeeze head formed by the side walls 9, the top plate 15 and the bottom flexible sand-engaging wall 7, 3. In this manner, the squeeze head is provided with two sealed

chambers

17 and 18 being horizontally separated by the intermediate diaphragm 13.

Into the compartment 18, there is provided a substan tially incompressible fluid such as water W and such water may be placed in such compartment by means of a fill aperture 19 and a vent aperture 20, both being ilmay mean a total pressure in excess of 100 tons. Since, of course, the air is laterally displaceable, the pressure over the entire upper surface of the diaphragm will always he the same at any spot thereon. Thus even though the diaphragm may bulge upwardly as indicated at 35, the pressure exerted by that portion of the diaphragm will be the same as that where it may bulge downwardly as indicated at 36. It is noted that the irregularities in the surf-ace of the diaphragms tend to conform to the irregularities in the surface of the pattern 4 and at high points of the pattern. The diaphragm will bulge upwardly and conversely, at lower points the diaphragm will generally bulge downwardly maintaining a somewhat uniform sand depth over the entire upper surface of the pattern. Since the air is quite compressible, it is desirable to have-a relatively small volume of air in the final compression stages of the operation as indicated in FIG. 2.

lustrated as plugged. The fluid in compartment 18 preferably completely fills such compartment and, in elTect, constitutes a water back-up for the compartment 17 and the lower relatively

thick diaphragms

7 and 8. A passageway 21 leading through the clamping ring 12, the side walls 9 and' the top plate extends to air inlet 22 through pressure regulator 24 and check valve 25. Through such inlets, a compressible fluid such as air A may be supplied to the compartment 17.

It is noted that the peripheral exterior dimension of the squeeze head is somewhat smaller than the peripheral interior dimension of the flask 2. As seen in FIG. 2, this relative dimensioning of the flask and squeeze head permits the squeeze head to telescope within the flask as the squeeze head and flask are moved relative to each other. To avoid wear on the exposed peripheral edges of the

diaphragms

7 and 8, peripheral side plates are provided shown at 27 and 28. These side plates also serve properly to rigidity the peripheral structure formed by the clamping ring 11 which, of course, serves as an annular squeeze biscuit adapted to engage the sand near the outer periphery of the flask to provide a rigid firm squeeze where the sand is deepest as indicated at 30 and 31 in P16. 2, since the pattern 4 does not generally extend too closely to the flask walls. The sides of the clamping ring 11 as well as the outer surface of the

plates

27 and 28 are beveled as shown to facilitate sand penetration. The outer side walls of the clamping ring 11 are similarly so beveled and also the inner side walls of such ring. Thus without reducing the clamping area of such ring, greater sand penetration is obtainable.

It can now been seen that there is provided in the FIGS.

1 through 3 embodiment, a foundry molding machine head comprising essentially a horizontally diaphragm compartmented chamber having a flexible sand engaging Wall provided by the

lower diaphragms

7 and 8 with fluids of different compressibility being segregated by the compartmenting diaphragm 13 and sealed in such compartments.

As seen in FIGS. 2 and 3, when the head and flask are movedrelatively to each other, the head will telescope withinthe flask squeezing the sand against the pattern 4.

.As the squeeze pressure increases, the flexible sand engaging wall of the squeeze head chamber formed by the

diaphragms

7 and 8 will flex and conform to the upper surface of the sand mold being produced. As the squeeze pressure increases, the air trapped in the chamber 17 by the check valve increases in pressure and, of course, reduces in volume. As the volume decreases, the pressure exerted by the air in the chamber 19 on the diaphragms 7 In fact, pressures in excess of 200 pounds per square inch are obtainable, and for medium size squeeze heads, this However, it is not desirable to have the sand engaging diaphragm touch a solid backing at the high points of the pattern as indicated by the upward bulge 35, since no further lateral displacement of the air would obtain at that spot. Accordingly, uniform pressures will not be then exerted over the entire upper surface of the sand mold. The water in chamber 18 segregated from the air in chamber 17 by the diaphragm 13 then serves to provide a backing for the squeeze head composed of an incompressible yet displaceable substance. When the

diaphragms

7 and 8 bulge upwardly as indicated at 35 and the upper diaphragm 7 engages the segregating diaphragm 13 as indicated at 37, the fluid within chamber 18 will displace laterally causing the diaphragm 13 to bulge downwardly as indicated at 39 as the liquid is thus laterally displaced. Such displacement of the liquid will, however, not affect the uniformity of the pressure per area force exerted by the squeeze head. Nor will such displacement affect the volume of compartment 17 and thus the pressure exerted by the air A. Only the movement of the sand against the

diaphragms

7 and 8 will reduce the volume of compartment 17. The liquid upper portion of the squeeze head is accordingly a safeguard obtaining both a small volume of air for the squeezing operation and a safety back-up for the squeeze diaphragm precluding pattern damage and non-uniformity of hardness in the sand mold.

When the squeeze head and flask are moved relatively apart as seen in FIG. 3, the

diaphragms

7 and 8 will reassume the position shown in FIG. 1 and the pressure within the chamber 17 will drop back to its original low level. The pattern will then be drawn, the sand mold removed, and a new flask placed in position and filled with sand.-

In FIGS. 4, 5 and 6, there is illustrated another embodi ment of the present invention wherein the squeeze head 1 is provided with a central support for the formation of a sprue opening and pouring basin in the sand mold. As seen more particularly in FIG. 5, the pattern comprises two main sections 4% and 41 interconnected by a dowei or like member forming the interconnecting passageway 42 and having a sprue pin or dowel extending vertically therefrom as indicated at 43. The members 42 and 43' form the gating system for the pattern, which, it will be understood, will be the passageways or sprue openings for the introduction of molten metal into the pattern formed cavities in the sand mold. A pouring'basin indicated at 44 will be formed in the finished sand mold adjacent the top of the vertically extending sprue opening provided by the sprue dowel 43. To form this pouring basin, the squeeze head is provided with a centrally located depending conoidal projection 45 having a centrally located vertically extending aperture 46 adapted to mate with the vertically projecting sprue dowel 43. The

pouring basin forming member 45 is supportedon the block 47 by elongated screws or the like 48. The block 47 is in turn welded directly to the underside of the top plate 15 of the squeeze head 1. Collars. or the like 4.9 sur-- rounding the screws 48 will serve rigidly to support the member 45' with respect to the plate 15 and thus the head i. The member 45 also serves as 'a center support for the

diaphragms

7 and 8 which are compressed between the flange portion 59 of the member 45 and spacer 51 separating such diaphragms from the diaphragms 13. in this embodiment, the

diaphragms

7, 3 and 13 are provided with central apertures aligned with central apertures in the blocks 4-7, 51 and the pouring basin forming member 45. Also, apertures may be provided in the plates 15 and the support 16 as indicated also aligned with the sprue dowel 43 to vent the aperture 46 as the squeeze head is brought into compression engagement with the mold box. Fasteners in the forms of screws 52 may be employed to hold the spacer 51 properly in position against the block 47 compressing the diaphragm thereagainst in sealed relation. Aside from the central support for the formation of the sprue and pouring basin, the squeeze head is otlerwise identical in form to the squeeze head shown in the embodiment of the invention in FIGS. 1 through 3. The

diaphragms

7, 8 and 13 are, however, both peripherally and centrally clamped to the squeeze head to provide, in effect, an annular flexible sand engaging wall, and similarly during the squeezing operation as shown in FIG. 5, as the

diaphragms

7 and 8 bulge upwardly due to the higher pattern portion 41, such diaphragms may engage the diaphragm 13 causing it also to bulge upwardly laterally to displace the water W causing the diaphragm 13 to bulge downwardly as indicated at 55' over the lower pattern portion 40.

Referring now to FIG. 6, to set up the squeeze head, it may be placed on a flat block 56 having a center cut-out portion 57 accommodating the pouring basin forming projection 45. The block is dimensionally smaller than the interior of the clamping ring 11 so that the head will be supported entirely upon the bottom diaphragm 3. Initially, the vent 20 may be unplugged, and the top chamber 18 may then be filled with water through the water inlet 19. When water has reached the vent level and runs over, the water may be shut off and both the vent and inlet passages may then be plugged. The squeeze head may then be removed from the flat block 56 and air pressure will be inserted into the lower into the lower relatively smaller chamber through the pressure regulator 24. Such regulator maintains a continuous low minimum of pressure within the chamber 17 and the

diaphragms

7 and 8 are caused to bulge downwardly as indicated, for example, in FIGS. 1 and 3. This low pressure is maintained at all times and during the squeeze operation, the check valve 25 traps air in the chamber 17 which thereby develops extremely high pressures as the squeeze stroke progresses.

Although the upper diaphragm 13 may seldom be bulged or distorted as indicated in FIGS. 2 and 5, it does provide an added safety feature in that should the flask be filled with insufficient sand, the patterns will not be damaged as the result of the

diaphragms

7 and 8 contacting a rigid non-displaceable back-up.

It can now be seen that there is provided a foundry molding machine squeeze head providing a uniform pressure over the entire upper surface of the sand mold during the squeezing operation utilizing both a compressible fluid and a displaceable yet incompressible back-up fluid.

Other modes of applying the principle of the invention may be employed, change being made as regards the de tails described, provided the features stated in any of the following claims or the equivalent of such be employed.

We, therefore, particularly point out and distinctly claim as our invention:

1. A squeeze head for foundry molding machines and ing a flexible wall vis-avis said diaphragm, a compressible fluid sealed in said cavity between said diaphragm and said flexible wall, and a substantially incompressible fluid sealed in said chamber.

2. A squeeze head as set forth in claim 1 including a generally centrally disposed rigid support for said diaphragm and flexible wall.

3. A squeeze head as set forth in claim 2 including a rigid pouring basin forming member projecting from said support.

4. A squeeze head as set forth in claim 1 wherein said flexible wall and said diaphragm are both peripherally secured to said cavity in vertically spaced. relation.

5. A squeeze head as set forth in claim 1 including means operative to supply regulated low pressure air to said cavity between said diaphragm and flexible wall.

6. A squeeze head for a foundry molding machine comprising a horizontally compartmented chamber with a diaphragm partition and a flexible sand engaging wall, and fluids of different compressibility segregated by said diaphragm partition and sealed in such compartments.

7. A squeeze head as set forth in claim 6 wherein said flexible sand engaging wall comprises two relatively thick diaphragms peripherally secured to the bottom of said head.

8. A squeeze head as set forth in claim 7 wherein such fluids comprise water and air, such air being sealed beneath said compartmenting partition diaphragm, and such Water being sealed above said compartmenting partition diaphragm.

9. The squeeze head as set forth in claim 8 including means operative to supply regulated low pressure air to said squeeze head, and means to trap such air in said squeeze head.

10. A squeeze head as set forth in claim 7 wherein such fluids comprise air and water, such air being adapted to be compressed and laterally displaced by engagement of said squeeze head with a sand mold and the like, and such water being adapted to be laterally displaced by engagement of said flexible sand engaging wall with said compartmenting partition diaphragm after such air has thus been compressed.

11. A squeeze head for foundry molding machines comprising a flexible sand engaging diaphragm peripherally secured to said head, an air chamber behind said diaphragm adapted to contain a fixed quantity of aira liquid chamber behind said air chamber, a second diaphragm forming a common partition for said liquid and air chambers adapted to be engaged by said first diaphragm laterally to displace such liquid upon the application of said squeeze head to a sand mold and the like.

12. A squeeze head for foundry molding machines comprising a variable volume air chamber having a flexible sand engaging wall peripherally secured to said head, a fixed volume liquid chamber completely backing up said air chamber, and a flexible partition separating said air and liquid chambers.

13. A squeeze head as set forth in claim 12 including means to maintain a fixed quantity of air in said air chamber.

14. A squeeze head as set forth in claim 12 wherein said flexible sand engaging wall comprises two juxtaposed relatively thick diaphragms.

References Cited in the file of this patent UNITED STATES PATENTS Taccone July 3, 1962

Claims

1. A SQUEEZE HEAD FOR FOUNDRY MOLDING MACHINES AND THE LIKE COMPRISING A DOWNWARDLY OPENING CAVITY, A DIAPHRAGM PERIPHERALLY SECURED TO SAID CAVITY EXTENDING ACROSS THE BOTTOM THEREOF, A CHAMBER IN SAID CAVITY HAVING A FLEXIBLE WALL VIS-A-VIS SAID DIAPHRAGM, A COMPRESSIBLE FLUID SEALED IN SAID CAVITY BETWEEN SAID DIAPHRAGM AND SAID FLEXIBLE WALL, AND A SUBSTANTIALLY INCOMPRESSIBLE FLUID SEALED IN SAID CHAMBER.