US2367727A - Apparatus for casting articles in permanent metal molds - Google Patents

Description

Jan. .23, E945. H. E. MCWANE APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 15, 1941 6 Sheets-Sheet 1 M 49, awzqgw Wag v Jan. 23, 1945. H. E. McWANE APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 13, 1941 6 Sheets-Sheet 2 Jim, 1945- H. E. McWANE 2,367,727

APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 13, 1941 6 Sheets-Sheet 5 jam. 23; 1945. H. E. MCWANE 2,367,727

APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 15, 1941 e Sheets-Sheet 4 v W 45 if ,4 I W W {I (@[iszr 23 Fig-45. McWANE 2,367,727

APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 13, 1941 6 Sheets-Sheet 5 APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Filed Dec. 15, 1941 e Sheets-Sheet 6 Patented Jan. 23, 1945 APPARATUS FOR CASTING ARTICLES IN PERMANENT METAL MOLDS Henry E. Mcwane, Lynchburg, Va.

Application December 13, 1941, Serial No. 422,912

3 Claims.

The present invention relates to the art of casting and more particularly to an apparatus for casting articles in permanent metal molds whereby deleterious strains due to shrinkage of the casting on cooling are eliminated. This case is a continuation in part of my co-pending application, Serial No. 281,973, filed June 29, 1939, and entitled Apparatus and method of casting.

It is, of course, well known that relatively thin articles, such as, plow mold boards and points, cool rapidly after the metal has been poured.

' the casting.

These articles are often formed with ribs, flanges,

apertures and the like, and the casting if maintained securely within a rigid permanent mold will cause weakened metal, or fractures between the ribs, flanges, etc., if the metal shrinks between them. Naturally the mold parts must be securely held in close contact with each other as the metal is being poured and while it sets to obtain a good casting. However, if the mold parts are held in the closed position during the cooling cycle of the metal, the. shrinkage of the cooling metal will cause the casting thus held to stretch beyond its elastic limit.

One of the paramount purposes of the present invention is to provide a permanent metal mold, the parts of which may be cracked or moved away from each other a. small distance after the molten material has been poured and has set, thereby permitting a free shrinkage of the casting independently of the mold. Or, to express it in a different manner, there is provided by the present application a method and apparatus whereby binding of the shrinking metal within the mold is eliminated.

.An important object of the present invention is to accomplish the above purpose.

And another object of the present invention is to provide an apparatus wherein a movable mold part is moved into operative position with respect to a fixed mold part during the pouring cycle,

then moving the movable mold part a suificient distance after solidification but before shrinkage of the molten material to permit the material to shrink in the mold but not far enough to allow the casting to fall from the mold and finally moving the movable mold part completely away from the fixed mold part to enable the .cast article to be removed.

And another object is to provide a timing cycle for casting in permanent metal molds whereby the mold is first automatically closed for pouring and is held in the closed position under pressure for a predetermined period whereupon the mold parts are separated slightly for a me determined period of time to enable the molten material to shrink and lastly the mold parts are completely separated to permit the removal of Yet a further object of the invention is to provide a novel time operated valve mechanism for actuating the movement of the movable mold part with respect to the stationary mold part.

And a further object of the present invention is to provide a plunger construction for moving a movable mold part away from a fixed mold part which operates in conjunction with a pressure closing means to separate the mold parts a predetermined distance.

To accomplish the above and other advantageous objects, I employ a fixed mold section and a movable mold section which is adapted to be moved into operative position with respect to the fixed mold section. The movable mold part is held against the fixed mold part for a predetermined period of time during the pouring step. The movable mold section is maintained in this position under pressure until the molten material has solidified but before it begins to shrink, at which time the movable mold section is automatically moved a short distance away from the fixed mold section to permit the casting to shrink freely within the mold. After the casting has completely cooled, the movable mold section is moved a further distance away from the fixed mold section thereby permitting the operator to have easy access to the mold for removing the cast article. A timing device is provided to control the cycle of the above functions.

In the drawings in which like numerals designate the same or similar parts:

Figure 1 is a top lan view of a casting machine embodying my inventive concept.

Figure 2 is a view in side elevation of the machine illustrated in Figure 1. Figure 3 is a sectional view taken along the line 3-3 of Figure 2. looking in the direction of the arrows.

Figure 7 is a sectional view taken along the line 1-1 of Figure 2 looking in the direction or the arrows.

Figure 8 is a sectional view taken along the line 8-8 of Figure 2 looking in the direction of the arrows.

Figure 9 is a conventionalized sectional view of the various mechanisms for operating the movable mold part.

Figure 10 is a diagrammatic representation 01 the timing mechanism for operating the casting cycle illustrating the mold parts in the operative position.

Figure 11 is a diagrammatic representation of the same parts shown in Figure 10 illustrating their position when the movable mold part is in position against the fixed mold part for the pouring step.

Figure 12 is a diagrammatic representation of the control cycle showing the relative position of the elements when the movable mold part is moved slightly away from the fixed mold part to permit the casting to shrink within the mold.

Figure 13 is a diagrammatic representation of the position of the elements constituting the control means when the movable mold part is moved completely away from the fixed mold part to permit the cast article to mold.

Referring to Figure 1, there is shown a casting machine designated generally I which employs a fixed bed plate 2 and a movable bed plate 3. The movable bed plate 3 is adapted to slide toward and away from the fixed bed plate 2 on tracks 4. A guide member is carried by each side of the movable bed plate 3 and adjustinggibs 6 are associated therewith for compensating for wear. One end of each guide rail 4 is secured to the fixed bed plate 2 as shown at I, and a yoke 8 joins the opposite ends of the guide rails 4.

The bed plate 2 is hingedly fixed to a support leg 9 as shown at ill to enable the frame i to be moved from the horizontal position illustrated in Figures 1 and 2 to the vertical position shown by the dot dash lines in Figure 5. The yoke 23 is adapted to rest on a support II when the frame is in the horizontal position and attention is called to Figure 2.

Bolted to the fixed bed plate 2 is one half [2 of a water jacketed permanent metal mold iii. The structure of the mold i3 is shown and described in my co-pending application, Serial No. 413,214, filed October 1, 1941. Conduits i l and i5 are in communication with the water jacket for circulating the necessary cooling medium in the water Jacket.

Secured to the movable bed plate 3 is the opposite half l6 of the mold l3 and when the two halves are in operative position they define therebetween a casting cavity ii. The mold half I6 is constructed in a manner similar to that of the mold half i2, and water is introduced and withdrawn from the jacket through conduits l4 and i5.

Hinging the machine i to enable it to bepositioned vertically, as shown in dot dash lines of Figure 5, greatly facilitates attaching the mold parts l2 and i6 thereto. These parts are, of necessity, bulky and heavy and difiiculty has been experienced in the past in properly aligning them in proper register with one another;

By positioning the machine vertically and separating the bed plates 2 and 3 by air pressure in the cylinder or otherwise, the mold part l2 may be easily positioned on the plate 2 in its approximately correct position. The part I6 is then be removed from th placed on top of the part l2 where it will naturally register with this part due to the shape of the parts, doweling or otherwise. Next the plate 3 is lowered into contact with the mold and the parts are bolted to their respective plates before the machine is lowered to its horizontal operative position.

In order to impart longitudinal movement to the bed plate 3 and as a consequence to the mold half i6, it will be seen that a spider I8 is suitably affixed to the movable bed plate 3. One end of a piston rod I9 is detachably secured to the spider as shown at 20. The rod l9 extends through a stuifing box 2| provided in the yoke 8 and into a cylinder 22 bolted to the yoke 8 as at 23. The opposite end of the rod l9 supports a piston head 24 which reciprocates within the cylinder 22. The end of the cylinder 22 is closed by means of a cap 25 and gasket 26 will afford a leak-proof union between the cap and the cylinder.

In the present invention, the movable mold half I6 is adapted to be moved into operative position with respect to the fixed mold half i3 by virtue of the piston 24 and held thereagainst under pressure for a predetermined P riod of time to enable the molten material to be poured into the mold l3. Means are then adapted to move the movable mold part IS a short distance away from the fixed mold part after the metal has solidified thereby eliminating deleterious strains due to shrinkage on cooling of the molten metal. The piston 24 is then moved to move the movable mold part l6 completely away from the fixed mold half l3 to enable the casting to be removed from the mold.

To release the movable mold part i6 immediately upon the expiration of a predetermined time interval from the fixed mold half, I provide a pair of release members 28. The release member 28 comprises a socket 29 that is detachably secured to the guide rail 4 slightly forward of the fixed bed plate. Mounted within the socket is a helical spring 30, one end of which bears against a threaded plug 3| that closes the end of the socket. The other end of the coil spring 30 engages a plunger 32 which projects through an aperture 33 in the other end of the socket. A bolt 34 havin a head 35 is threaded into the bore of the plunger 32. The spring 30 will maintain the parts normally in the position shown in Figures 1 and 4. When the piston 24 moves the bed plate to the position where the mold half I6 is in engagement with the mold half i3 for the pouring cycle, the guide members 5 carried by the movable bed plate will engage the bolt head 35 and compress the spring 30 to move the plunger to the position shown in Figure 3. However, as soon as the fluid pressure on the piston head 24 is released, the spring forces the plunger 33 and the bolt 35 toward the right thus cracking slightly the mold parts l6 and I3 and enabling the casting to shrink freely within the mold cavity. Of course, by proper manipulation of the bolt 34 it is possible to vary the amount of movement of the movable part away from the fixed part. This structure will eliminate undesirable strains which would be encountered during the shrinking of the molten metal if the mold had not been cracked.

The control for operating the movement of the movable mold part with respectto the fixed mold part i3 is accomplished by means of an electrically operated valve control indicated generally 40. The valve control 40 comprises a solenoid operated three way valve 4| and a solenoid controlled pneumatic operated four way valve 42.

As best shown in Figure 9, the valve 4| includes a body portion 43, inlet seat 44 and outlet seat 45. The seats 44 and 45 are adapted to be closed by opposed spring loaded discs 46 and 47, respectively. The discs 48 and 41 are operated by a lever 48 that is operatively connected at 48 to a plunger of solenoid 5i mounted on the valve body 33.

The body is further provided with an inlet port E and an outlet port F which communicates with the head end of cylinder 22 through a conduit 52. Exhaust port G is also formed in the body 43.

The four way valve 42 comprises a body portion 42 and inlet port A through which fluid is introduced by pipe 52'. There is further provided an exhaust portB and an outlet port C which is connected to the-rod end of the cylinder 22 by means of a conduit 53. Mounted-within the valve body it are opposed spring loaded discs 54 and 55 that close valve seats 55 and 57, respectively, to control the flow of air to the pipe 53. Also, spring loaded discs 58 and 59 are adapted to seal seats 68 and ti, respectively, to control flow of air through port D to a pipe 53' connected with the inlet port E of the valve 4H. t

The discs 5d, 55, 58 and 59 are moved-by means of a mushroom head 53 that is actuated by a flexible diaphragm Bil secured within the body 42'.

The air which operates the diaphragm 84 is controlled by means of a solenoid valve 65 which is similar in construction and operation to the valve ll This valve has ports b, d slide and port b is connected with port a on the pressure side of the four way valve througha conduit 66. The

port d is in communication with the port 0 on theexhaust side of the four way valve through connection 68 and port 9 is connected to port f by means of a pipe 69.

The timing mechanism for operating the valve control fill and the movable mold part i6 is best shown in Figures 10 to 13 inclusive; It comprises a shaft it! which carries spaced segments ll, 12 and i8 and a collector ring i4. Rotary movement is imparted to the shaft 10 through a worm wheel '75 and a worm gear '78. Theworm gear 15 may be driven from any suitable source of power such as a constant speed motor 16'. In this particular embodiment, the cycle of casting operations extends for a period of one minute and consequently I provide 60 segments that are spaced 30 apart. It will be appreciated therefore that each cycle of operation occurs at intervals of ten seconds. While the above length-and stagger of segments are used as an illustration other variations may be employed to suit diiferent operating conditions.

asema'z The solenoids 5| and 85 are connected by lead lito one terminal of a source of electrical energy and the other terminal has a contactor 18 which contacts collector ring 14. A signal light I9 is interposed in the lead I? and is connected through line 80 witha contactor 8| that makes contact with the segment 7|. Solenoid 5| has a lead 82 which terminates in contactor 83 adapted to make contact with segment 13 and solenoid is also connected through a line 84 with a contactor 85 which will make contact with the seg-' ment '12.

In Figure 10 I have shown diagrammatically prise a double check valve.

. 3 inder through connection 52, port F, port E of the three way valve 4|, port D, and out through exhaust port B in the four way valve. At this particular stage the solenoids 5| and 65 are deenergized and the signal lamp 79 has just become lighted indicating a ten second interval before the mold closes. The position orthe solenoid valves is that shown in Figure Upon the expiration of the ten second interval, the circuit to the signal lamp 1! is still maintained through segment 1|, line 80 and line ll.

At the same time the circuit is completed to the solenoid 65, through segment 12, contactor 85, line 84 and back to the load line 17. At this time the air entering the four way valve 42 leaves through port D, through pipe- 53 to port E in the valv 4|, out through port F into the head end of the cylinder through pipe 52 to move the movabl mold part into operative position with respect to the fixed mold part for the pouring operation. The air is exhausted from the rod end of the cylinder through line 53. port C in the valve 42 and out through the exhaust port B.

At the beginning of the third cycle, the circuit to the signal lamp is broken as the segment 1| moves out of contact with contactor 8| indicating that the mold is' about to crack. Contactor 85 is still in contact with segment 12, thus keeping solenoid 85 energized. The contactor 83 now makes contact with segment 13 and the circuit to solenoid 5| is completed, thereby energizing said solenoid. At this time air pressure from the valve 42 is prevented from passing valve 4| and reaching the cylinder 22 by reason of the fact that the valve seat 44 of the valve 4| is closed. Exhaust port G of valve 4| is connected to port F as disc 41 is lifted from its seat 45. This allows free exhaust of the air in the head end of cylinder 22 through ports F and G of valve 4 I, thereby permitting free movement of the piston 24. Consequently the release members 28 may now function to move the mold part l6 slightly away from the mold part |2 to permit the casting to shrink free of the mold cavity.

At the beginning of the final cycle of operations, solenoid 5| is energized and solenoid 65 becomes de-energized and the signal lamp is out. The air entering valve 42 through port A leaves through port C through line 53 to the rod end of the cylinder to move the piston'head toward the right as shown in Figure 13. The air at the head end of the cylinder is exhausted through conduit 52 through port F at the valve 4| and out through exhaust port G. During this cycle the movable mold part I6 is moved to its completely open position to permit the casting to be removed from the mold.

Thetiming mechanism continues its operation and the cycles above described are again repeated and these cycles will continue to be repeated until the motor driving the worm wheel and worm gear 15 and 15, respectively, is stopped.

To control the rate of movement of the piston 24, speed control devices may be inserted in the air conduits 52 and 53. These speed controllers are designated 86 and 81, respectively, and com- Each valve is provided with a port 88 to permit air to be admitted to the cylinder 22' and a port 89 to permit air to be exhausted therefrom. Each of these ports is adapted to be opened and closed by discs 90 and.

provide a dampening efleot for the movement of the piston.

It is thought apparent from the above description that I have provided a casting machine wherein a movable mold section is moved into operative position with respect to the fixed mold section for a predetermined period of time to permit pouring of the molten metal into the mold. Immediately upon the expiration of a certain amount of time the movable mold part is moved slightly away from the fixed mold part to permit the casting to shrink freely within the mold thereby preventing deleterious strains being imposed on the castings. After the casting has cooled, the movable mold section is moved completely away from the fixed mold section to permit the casting to be removed from the mold.

The above cycle of operations is automatic and permits a multiplicity of castings to be cast within a minimum of time and with a minimum of effort on the part of the foundryman.

I claim:

1. In a permanent metal mold having a stationary mold block and a movable mold block adapted to be moved into engagement with the stationary block to close the mold and away from the stationary block to open the mold, a reciprocable actuating device responsive to differential in pressure on opposite sides thereof and operativel connected with the movable block, valve means serving to apply fluid pressure on either of said actuating device and release pressure on the opposite side, additional valve means associated with the first valve means for controlling the application and release of pressure on one side of said actuating device, and means for operating said valves whereby fluid pressure is applied to one side of the actuating device and released from the opposite side to close the mold, then simultaneously released from both sides to permit free movement of the movable block with respect to the stationary block and then applied to the opposite side and released from the first mentioned side to open the mold.

2. In a permanent metal mold having a stationary mold block and a movable mold block adapted to be moved into engagement with the stationary block to close the mold and away from the stationary block to open the mold, a reciprocable actuating device responsive todiflerential in pressure on opposite sides thereof and operatively connected with the movable block, valve means serving to apply fluid pressure on either side of said actuating device and release pressure on the opposite side, additional valve means associated with the first valve means for controlling the application and release of pressure on one side of said actuating device, means for operating said valves whereby fluid pressure is applied to one side of the actuating device and released from the opposite side to close the mold, then simultaneously released from both sides to permit free movement of the movable block with respect to the stationary block and then applied to the opposite side and released from the first mentioned side to open the mold, and spring means for separating the movable block irom the stationary block during the period of free movement of said movable block.

3. In a permanent metal mold having a stationary mold block and a movable mold block adapted to be moved into engagement with the stationary block to close the mold and away from the stationary block to open the mold, a reciproca-ble actuating device responsive to ditfcrential in pressure on opposite sides thereof and operatively connected with the movable block valve means serving to apply fluid pressure on either side of said actuating device and release pressure on the opposite side, additional valve means associated with the first valve means for controlling the application and release 0! pressure on one side of said actuating device,

means for independently operating the valves, and a timing device for controlling the operation of said operating means to thereby apply pressure to one side of the actuating device and release pressure from the opposite side to close the mold for a predetermined interval of time, then release pressure simultaneously from both sides of the actuating device for a second predetermined interval of time and finally apply pressure to the opposite side of the actuating device and release pressure from the first mentioned side to open the mold.

- HENRY E. McWANE.

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