US3587714A - Foundry sand article forming machine - Google Patents

Abstract

FOUNDRY SAND ARTICLE FORMING MACHINE AND METHOD UTILIZING A SAND-RESIN MIXER, BLOWING THE MIX INTO A HORIZONTALLY SPLIT MOLD BOX; A GASSING HEAD WHICH CAN BE MOVED ABOVE THE BOX AND CLAMPED THERETO WITH AND AIR LINE CONNECTED THERETO AND AN INJECTOR OPERATIVE TO INSERT A PREDETERMINED AMOUNT OF CATALYST INTO THE LINE TO BE BLOWN THROUGH THE MOLD AT HIGH PRESSURE TO CURE THE MIX; UNLOCKING THE BOX HALVES WHILE LOCKING THE UPPER HALF TO THE GASSING HEAD, UNCLAMPING THE BOX VERTICALLY TO SEPARATE THE HALVES WITH STRIPPING MECHANISMS INCORPORATED IN EACH HALF.

D R A W I N G

Description

United States Patent 2,957,212 10/1960 Nikiatchen 164/16 3,030,675 4/1962 Chiabotti..... 164/16X 3,059,294 10/1962 Dunn et a1. 164/16X 3,253,304 5/1966 l-latch 164/12 Primary Examiner-J. Spencer Overholser Assistant Examiner.l0hn S. Brown Attorney-Oberlin, Maky, Donnelly and Renner ABSTRACT: Foundry sand article forming machine and method utilizing a sandresin mixer, blowing the mix into a horizontally split mold box; a gassing head which can be moved above the box and clamped thereto with an air line connected thereto and an injector operative to insert a predetermined amount of catalyst into the line to be blown through the mold at high pressure to cure the mix; unlocking the box halves while locking the upper half to the gassing head, unclamping the box vertically to separate the halves with stripping mechanisms incorporated in each half.

7 '10 H 44 f i l 53 I \f- 52 43\ 40 \/LH 28 I 29 30 i 24 J82 r84 25 I 1 i fi nNi-fi 87 75 mw |H|||| PATENIEU JUN28|97| 5 77 saw 1 or 3 IOI 9O INVENTORS ROBERT W. ELLMS 5.25. E V EDWARD 0. ABRAHAM ATTORNEYS PATENTED m2 8 I971 SHEET 3 OF 3 INVENTORS ROBERT W. ELLMS M H N M M Km 6 0 m M W lumm a imb FOUNDRY SAND ARTICLE FORMING MACHINE This invention relates generally as indicated to a foundry sand article forming machine and method and more particu larly to a machine and method for quickly and completely curing a foundry sand article.

In, for example, the ASI-ILAND process for producing foundry sand molds or cores, sand is first mixed with a resin which can then be blown into a mold box and when a catalyst, triethylamine, known as TEA is added, this causes the mixture to harden in seconds without heat. The basic problem is to ensure that the formed foundry sand article is quickly and thoroughly permeated or gassed with the catalyst. Additional problems arise because of the nature of the catalyst which can, under certain circumstances, be explosive. The catalyst is also toxic and inconvenient to handle. These latter problems are accentuated if excess catalyst is employed in an effort to ensure complete curing. When excess catalyst is used, it is necessary to capture the exhaust fumes and pass them through a scrubber.

Heretofore, the catalyst has been placed in a tank and nitrogen bubbled through it to suspend and carry the catalyst into the core or mold by relatively low pressure air or actually drawn through the mold or core by vacuum. In any event, gas generating apparatus utilizing what might be termed a bubbler method or carburetion process employing vacuums result in relatively complex equipment wherein it is difficult to meter the precise amount of the catalyst required to cure correctly the mold or core.

It has been discovered that the catalyst in liquid form can be injected in a metered quantity directly into an air line to be blown into and through the mold or core.

It is accordingly a principal object of the present invention to provide a foundry sand article forming machine and method wherein the catalyst for curing the sand-resin mix can be injected directly into an air pressure line in liquid form.

Another principal object is the provision of such machine and method wherein the catalyst in liquid form is finely divided or atomized and forced by high pressure air through the blown mold or core.

A further object is the provision of a foundry sand article forming machine and method wherein the amount of catalyst required to cure the mold or core can be carefully metered.

Another object is the provision of a foundry machine utiliz ing a highly simplified system for introducing the required amount of catalyst into the sand article.

Yet another object is the provision of such machine utilizing a unique mold or core box permitting the complete curing of the sand article automatically stripping the article therefrom when the box is opened.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

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 principles of the invention may be employed.

In said annexed drawings:

FIG. 1 is a side elevation partially broken away of a machine in accordance with the present invention as viewed from the line 1-1 ofFlG. 2;

FIG. 2 is a front elevation ofthe machine shown in FIG. 1;

FIG. 3 is an enlarged vertical section illustrating the mold or core box clamped in blow position with the sand article blown therein;

FIG. 4 is a view similar to FIG. 3 illustrating the gassing head being positioned between the box and the blow head;

FIG. 5 is a view similar to FIG. 3 illustrating the gassing head between the box and blow plate;

FIG. 6 is a view similar to FIG. 4 illustrating the box opened with the upper portion being locked to the gassing head;

FIG. 7 is a view similar to FIG. 6 illustrating the box being reassembled and unlocked from the gassing head;

FIG. 8 is an enlarged view of the catalyst gassing unit; and

FIG. 9 is a schematic diagram of such gassing unit showing the high pressure airline into which the catalyst is injected.

Referring now to the annexed drawings and more particularly to FIGS. 1 and 2, it will be seen that the illustrated machine comprises a base 1 on which is mounted an upstanding C-shape frame comprised of upper and lower horizontal members 2 and 3 and a vertical member 4 at the rear of the machine. The lower frame member 3 supports for vertical movement a clamp table 6 on bellows 7 while the upper frame member includes at its outer end a reservoir 8, the lower end of which is provided with a blow plate 9 having nozzles 10 projecting downwardly therefrom. A cutoff valve is mounted in housing 11 while a fill sleeve 12 extends thereabove. A blow valve 14 is mounted on the upper frame member 2, which when the cutoff valve within housing 11 is closed, will admit high pressure air to the reservoir 8 to blow the sand-resin mix therewithin through the nozzles 10.

Sand-resin mix is admitted to the reservoir when the valve within housing 11 is opened from a three stage mixer shown generally at 15 which is supported on frame 16 in turn mounted on the upper frame 2. The mixer is driven by motor 17 and is effective thoroughly to mix one or more resin binders with sand being fed to the mixer through hopper 18. The output of the mixer is discharged directly into the fill sleeve 12.

Mounted on the clamp table 6 is a mold or core box shown generally at 20 and in greater detail in FIGS. 3 through 7. Although in the illustrated embodiment a core is being formed, it will be appreciated that the terms mold" or core as far as the context of the machine is concerned may be used interchangeably since in any event a sand article is formed.

The box is of the horizontally split type including an upper and lower section 21 and 22, respectively. The lower section of the box 22 is mounted on the clamp table 6 and includes notches 24 and 25 at each side adapted to receive projections 26 and 27, respectively, of escapement pawls 28 and 29. These pawls are pivoted at 30 and 31, respectively, on brackets 32 projecting from the side of the upper box section 21.

As seen more clearly in FIG. 2, these pawls may be pivoted simultaneously in opposite directions by means of pistoncylinder assembly 34, the blind end of the cylinder being pivoted at 35 to the pawl 28 while the rod is pivotally connected at 36 to the pawl 29. Extension of the piston-cylinder assembly 34 will move the pawls to the position seen more clearly in FIG. 5, for example, while retraction will move the pawls to the position shown more clearly in FIGS. 3 or 4, for example.

The upper ends of the pawls 28 and 29 are provided with inwardly directed projections seen at 38 and 39 which are adapted to flt within slightly vertically elongated notches 40 and 41 of gassing head 42. Such gassing head includes a bottom relatively thick plate 43 and upstanding sidewalls 44 and 45 as well as upstanding front and back walls 46 and 47, respectively, seen more clearly in FIG. 1. The gassing head is thus in the form of an open top box and the upper peripheral edge thereof may be provided with a seal seen at 49 which, when the head is elevated, bears against the peripheral ring or gasket 50 on the underside of the blow plate 9. The depth of the boxlike head is, of course, sufficient completely to enclose the downwardly projecting nozzles 10 so that sand within such nozzles as seen in FIG. 5 cannot be exposed to the catalyst.

The bottom plate of the head is provided with a manifold seen at 52 in FIG. 5 which is connected to flexible air line 53. The manifold is provided with one or more ports 54 on the underside of the plate 43 communicating with the open top 55 of the upper mold box section 21. Such opening is formed by an inwardly directed plate or flange 56 downwardly from which extend rods 57 on which are mounted stripping plate 58. Compression springs 59 surround the rods between the flange 56 and the plate 58 urging the stripping plate downwardly as seen.

Laterally of the mold surface 60 formed by the mold box section 21 plungers 62 and 63 project through the box and in their lowermost position project beyond the interface 64 between the upper and lower mold box sections 21 and 22, respectively. The stripping plate 58 is also provided with stripping pins seen at 65 which when the plate is extended will project downwardly stripping the mold or core formed within the box from the mold surface 60. The stripping plate 58 is provided with apertures seen at 67 which accommodate the nozzles 10.

In the blow condition, with the assembled box halves clamped against the blow plate 9, the nozzles 10 fit within the countersunk bores 68 in the upper wall 69 of the mold section 21 with the tips 70 of the nozzles being substantially flush with the mold wall surface. As seen, vents 71 may be strategically arranged in the upper wall 69. A peripheral seal 72 is provided on the upper outer edge of the top mold box section 21.

The lower mold box section 22 is provided with a cavity 75 in which is mounted stripping plate 76 on posts 77 with compression springs 78 surrounding such posts and urging the stripping plate upwardly. The stripping plate is provided with plungers 79 and 80 aligned with the plungers 62 and 63 of the upper stripping plate 58 which, when the stripping plate is extended, would extend beyond the interface 64 between the two mold box sections. These plungers are, of course, positioned laterally of the mold surface 82. Stripping pins 83 are provided projecting upwardly from the stripping plate and through the mold wall 84, the upper ends of which are flush with the mold surface when the upper ends of the plunger 79 are flush with the interface 64. Again, the mold wall 84 is provided with strategically arranged vents as seen at 85. The cavity 75 is in communication with the flexible exhaust line 86 connected to the side of the lower mold box section as seen at 87. A peripheral seal 88 is provided at the top of the lower section.

Referring again to FIGS. 1 and 2, it will be seen that the gassing head 42 is provided with front and back extensions 90 and 91 by means of which the head is pin supported on the legs of a U-shape frame 92 which is mounted on bushing or collar 93. A gusset plate 94 is provided between the underside of the back or bight portion of the frame 92 and the collar 93. The collar may be journaled on a hollow pin extending between upper and lower brackets 96 and 97 mounted on the side of the vertical frame 4. A piston-cylinder assembly 98 pivotally mounted between brackets 99 and 100 also on the side of the frame 4 has its rod pin-connected at 101 to the collar so that the entire collar and frame 92 can be pivoted approximately 90 upon retraction or extension of the pistoncylinder assembly'98 to position the gassing head 42 between the blow plate 9 and the mold box 20. For convenience, the flexible air pressure line 53 may extend through the hollow pin pivotally supporting the collar 93. It can thus be seen that by retraction ofthe piston-cylinder assembly 98, the gassing head 42 may be pivoted to the side of the machine and upon extension the gassing head will be positioned directly vertically between the mold box and the blow plate.

The catalyst injection system 102 may be mounted in housing 103 seen in FIG. 1 directly behind the machine. This unit, with the housing removed, is seen in greater detail in FIG. 8 and comprises a base 104 having an upstanding mounting plate 105. On one side of the plate 105 there is provided a scrubber tank 106 and on the other side there is secured by suitable brackets a tank 107 for the liquid catalyst, and injection pump 108. A line lubricator 109 and filter 110 may also be included as well as additional valves and controls seen better schematically in FIG. 9.

From FIG. 9, it can be seen that the injection pump comprises a cylinder 112 having a rod plunger 113 with piston 114 on the end thereof. A compression spring extends between fixed partition 115 through which the rod 113 projects and the piston 114 as indicated at 116. The plunger projects through the partition 115 into what may be termed metering chamber 117. The extent to which the plunger projects into the metering chamber is governed by adjusting screw 119.

Air for operating both the injection pump and forcing the catalyst through the mold or core is supplied from source 121 at relatively high pressure, for example, from about to about I00 p.s.i. The air passes through filter and safety valve 122 to pilot operated shutoff valve 123 which may be operated either automatically or manually from pilot line 124. The line 125 leading from the valve 123 includes a branch 126 leading to pilot operated two way valve 127. In the position illustrated for such valve, the line 128 connected to the injection pump is vented. When the valve 123 is opened, the line 125 and thus the branch 126 is pressurized shifting the valve 127 to apply the line pressure through lubricator 109 to the piston 114. This causes the plunger 113 to move forwardly to the extent permitted by the position of the screw 119 forcing liquid catalyst from the chamber 117 through check valve 130 into the line 125. The high pressure air in line 125 hits and carries the liquid catalyst into the box 20 through the gassing head 42 through filter 131 which may be of the porous metal type. The filter may assist in atomizing the liquid catalyst in the air stream. The gassing head and core box will, of course, be clamped together and in the position indicated more particularly in FIG. 5.

Referring to such FIG., it will be seen that the air stream with the finely divided liquid catalyst therein enters the gassing head through the line 53 passing into the manifold 52 and from the ports 54 moving through the blown core or mold by means of the vents 71 as well as the openings 67 and 68. It has been found that the catalyst carried by the high pressure air will reach all parts of the blown mold or core and start the curing process immediately. The air pressure will pass through the sand article and out the vents 85 into the chamber 75 in the lower box section and then through the line 86 to the scrubber tank 106. The mold or core will harden in approximately 6 to 10 seconds and the air pressure may be held on for approximately 1 or 2 additional seconds to purge the mold or core of any undesirable products attendant to the chemical reaction of the cure or any excess catalyst.

With this injection process, it is possible to dispense with the scrubber 106 because a precisely metered amount of catalyst can be injected into the line thus avoiding excess catalyst in the exhaust line 86. However, a scrubber may be provided if desired by health or safety standards. In any event, the exhaust may bubble through the acid bath in the scrubber and to atmosphere as indicated at 133.

At the completion of the injection cycle, the valve 123 is shutoff and the valve 127 returns to its position shown venting the line 128 so that the spring 116 will return the piston 114 to the end ofits stroke. This, of course, draws additional catalyst into the chamber 117 from the tank 107 through the check valve 134. The pump is thus automatically replenished for the next injection cycle.

The precise volume of the pump for any particular mold or core can be obtained empirically during setup and to facilitate this the screw 119 may be provided with a micrometer type adjustment. For a given core or mold, the operator may cure specimen cores increasing the volume of the pump in given increments until the precise amount of volume of liquid catalyst required properly to cure the core is obtained. Once the precise volume setting is obtained for any given article, the setting, of course, will be left at that position for all subsequent given articles. With this injection process, it has been found that the cores or molds can be cured so quickly that the finished sand article can easily be stripped from the mold, there being very little time for the article to bond to the mold wall surfaces.

OPERATION Referring back to FIG. 3, it will be seen that the box, with the halves held together by the pawls 28 and 29 in the position shown, is elevated by the clamp table 6 against the blow plate 9. In such position, the pawls 28 and 29 are in engagement with the notches 24 and 25 in the lower mold box section holding the mold box halves together. When the box halves are held together by the pawls, the opposed plungers 62, 79 and 63, 80 compress the stripping springs 59 and 78 and hold the stripping pins flush with the mold surfaces. As the assembled box is elevated, it is clamped against the blow plate 9 and the nozzles are accordingly inserted into the apertures therefor so that the assembled mold is held in place to be filled with the sand-resin mix. When the sand-resin mix is blown into the mold as seen in FIG. 3, the mold will be filled and vented through the vents indicated. A valve 140 seen in FIG. 9 may be opened necessary the blow to provide the necessary venting. This valve is connected to lines 141 and 142 and will be closed during the subsequent gassing operation.

Moving now to FIG. 4, the assembled box is lowered to permit the gassing head 42 to be swung into proper position thereabove between the top of the mold box and the blow plate 9 as seen in FIG. 4. This is, of course, accomplished by extension of the piston-cylinder assembly 98 seen in FIG. 1. The table 6 is now again elevated picking up the gassing head from the supporting arms and clamping the mold box against the gassing head which in turn is clamped against the blow plate 9. This encloses the nozzles 10 and, of course, excludes any catalyst from the sand still within the nozzles. At this point, the piston-cylinder assembly 34 can now be extended rocking the pawls 28 and 29 to the position shown in FIG. 5. The mold box halves will still be held together due to the action of the clamping table 6. At this point the valve 123 is opened to send high pressure air through the formed sand article simultaneously injecting into the high pressure air line the given volume of liquid catalyst. As previously indicated, the air pressure will remain on the few seconds longer than that necessary to force the catalyst through the sand article to purge the lines and the sand article of any possible harmful undesirable byproducts or excess catalyst. At the end of the relatively short gassing cycle of from about 6 to about 12 seconds, the valve 123 is closed and the metering pump 108 automatically recharges itself for the next cycle. In certain instances it may be desirable to give the article another shot" and this can be done by again opening valve 123.

Moving now to FIG. 6, with the box halves unlocked, the table 6 is now lowered. The upper half 21 of the box will be lifted off the lower half as the table descends when the gassing head is supported on the arms of the frame 92. This permits the stripping springs to extend stripping the sand article C from the mold surfaces and as seen in FIG. 6 it will be supported on the lower pins 83 so that the operator may reach in and remove the same from the machine. Automatic sand article removal devices may be provided if desired.

With the sand article removed, the box may be reassembled by again elevating the table 6 causing the plungers 79 and 80 to engage the plungers 62 and 63 compressing the springs 59 and 78 repositioning the tips of the stripping pins flush with the mold surfaces. When this has occurred and the assembly is clamped in the position shown in FIG. 7, the piston-cylinder assembly 34 may be retracted repositioning the pawls to lock the box halves together as seen. The table 6 is now lowered to place the gassing head on the frame 92 which is then retracted by retraction of the piston-cylinder assembly 98. The machine will then repeat its above-described cycle to form another sand article.

It can now be seen that there is provided a highly simplified machine and method for quickly forming sand molds or cores wherein the catalyst for curing the sand-resin mix is injected directly into a high pressure air line in liquid form and is forced in finely divided form through the formed sand article. In this manner, the precise amount of catalyst required thoroughly to cure the sand article can be employed avoiding the usual hazards present when excess catalyst is used. Moreover, the machine itselfis provided with a unique box arrangement cooperating with the gassing head quickly automatically to strip the sand article from the mold surfaces.

Other modes of applying the principles of the invention may be employed, change being made as regards the details 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:

We claim:

1. In apparatus for forming foundry sand molds, cores and the like, means operative to place a sand-resin mix into a mold box, an air line leading to said mold box, and metering pump means operative to inject a predetermined amount of liquid catalyst into said air line to be forced through said mold to cure such sand-resin mix.

2. In apparatus for forming foundry sand molds, cores and the like, means operative to place a sand-resin mix into a mold box, an air line leading to said mold box, and means operative to inject a predetermined amount of catalyst into said air line to be forced through said mold to cure such sand-resin mix, said last mentioned means including a tank for liquid catalyst, a second line leading from said tank to said air line, an injection pump in said second line operative on one stroke to force liquid into said air line and on the other to draw liquid from said tank,

3. Apparatus as set forth in claim 2 including check valves on opposite sides of said pump limiting liquid flow from said tank to said pump to said air line only.

4. Apparatus as set forth in claim 3 wherein said pump includes a chamber in liquid communication with said second line with a piston projecting therein, and means to move said piston to displace liquid from said chamber.

5. A paratus as set forth in claim 4 including an adjustable abutment for said piston whereby the volume of liquid displaced by said piston may be precisely controlled.

6. Apparatus as set forth in claim 5 wherein said means to move said piston comprises air pressure from said air line.

7. Apparatus as set forth in claim 6 including a spring return for said piston, and a two way pilot operated valve operative to pressurize said piston when said air line is pressurized.

8. Apparatus as set forth in claim 1 including a gassing head, said air line being connected to said gassing head, and means operative to clamp said head against said box before pressurization ofsaid air line.

9. Apparatus as set forth in claim 8 including table means operative to elevate said box against a blow plate for filling of said box, and means operative to interpose said gassing head between said blow plate and box to be clamped therebetween by elevation of said table.

10. In apparatus for forming foundry sand molds, cores and the like, means operative to place a sand-resin mix into a mold box, an air line leading to said mold box, means operative to inject a predetermined amount of catalyst into said air line to be forced through said mold to cure such sand-resin mix, a gassing head, said air line being connected to said gassing head, means operative to clamp said head against said box before pressurization of said air line, table means operative to elevate said box against a blow plate for filling of said box, and means operative to interpose said gassing head between said blow plate and box to be clamped therebetween by elevation of said table, said blow plate including downwardly projecting nozzles, said gassing head including upstanding walls operative to enclose and seal off said nozzles during the curing of the sand article.

11. Apparatus as set forth in claim 8 including a frame supporting said gassing head, and means operative to swing said frame to and from a position above said box.

12. In apparatus for forming foundry sand molds, cores and the like, means operative to place a sand-resin mix into a mold box, an air line leading to said mold box, and means operative to inject a predetermined amount of catalyst into said air line to be forced through said mold to cure such sand-resin mix,

said last-mentioned means comprising a pump having an adjustable volume.

13. In apparatus for forming foundry sand molds, cores and the like, means operative to place a sand-resin mix into a mold box, an air line leading to said mold box, and means operative to inject a predetermined amount of catalyst into said air line to be forced through said mold to cure such sand-resin mix, said last-mentioned means comprising a piston type single acting pump having an adjustable stroke.

14. In apparatus for forming foundry sand molds, cores and having a predetermined stroke. the like, means operative to place a sand-resin mix into a mold Apparatus as set forth in claim 1 including means open box, an air line leading to said mold box, and means operative nve to pressurize said air line at approxlmately 90 pm. to

to inject a predetermined amount of catalyst into said air line f to be forced through said mold to cure such sand-resin mix, owe sald Injected catalyst through sald mold said last-mentioned means comprising a single acting injector

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