US3470941A

US3470941A - Apparatus for casting metal into each of a series of molds

Info

Publication number: US3470941A
Application number: US525797A
Authority: US
Inventors: Earl A Thompson
Original assignee: EARL A THOMPSON Manufacturing CO
Current assignee: EARL A THOMPSON Manufacturing CO
Priority date: 1966-01-10
Filing date: 1966-01-10
Publication date: 1969-10-07
Anticipated expiration: 1986-10-07

Description

APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS Filed Jan. .10, 1956 Oct. 7, 1969 E. A. THOMPSON 7 Sheets-Sheet 1 I INVENTOR. EARL A. TH OM PSON Oct. 7, 1969 E. A. THOMPSON APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS Filed Jan. 10, 1966 7 Sheets-Sheet 2 INVENTOR.

EARL ATHOIVIPS AGE/VT Oct. 7, 1969 E. A. THOMPSON APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS 7 Sheets-Sheet %,4, fl #Ml N .0 m8 4 m w M w M m 5 H m IV. 6 RB J A E w 2 0 yam-W6 M44. 4 I a 6M. 0 p3 AGENT 1969 E. A. THOMPSON 3,470,941

APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS INVENTOR.

EAR%YA.THOMPSON W fwd AGENT Oct. 7, 1969 E. A. THOMPSON 3,470,941

APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS Filed Jan. 10. 1966 '7 Sheets-Sheet 5 w s: I

lxvzslvTok. EARL A THOMPSON Attorney Oct. 7, 1969 E. A. THOMPSON 3,470,941

APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS Filed Jan. 10. 1966 7 Sheets-Sheet R IN VEN TOR.

EARL ATHOMPSON AGENT Oct. 7, 1969 E. A. THOMPSON APPARATUS FOR CASTING METAL INTO EACH OF A SERIES OF MOLDS Filed Jan. 10, 1966 7 Sheets-Sheet 7 INVENTOR. EA R 1 A. THGIVI PSO N United States Patent US. Cl. 164-337 13 Claims ABSTRACT OF THE DISCLOSURE Small articles, for example bodies for hydraulic valve lifters, are cast of two metals by indexing a series of molds past a pair of bottom-pour furnaces. A melting furnace and portable holding furnace are associated with each bottom pour furnace. The bottom-pour arrangement includes a valve seat up inside the furnace to surround the seat with molten metal. It also includes a delivery passage whose walls are remote from the pour orifice of the valve, and separated from the pour orifice by an abrupt edge to prevent spattering of metal onto the walls. The disclosure includes a method of casting wherein the metal is heated well above its melting point before the valve is opened to prevent sticking of the valve to its seat.

This invention relates to improvements in machines for automatically casting metal articles sequentially in mass production quantities, and specifically for casting each article of a plurality of metals.

l "This application is a continuation-in-part of my application Ser. No. 207,673, filed July 5, 1960, to be abandoned.

Conventional foundry practice involves large molds having a number of mold cavities, often numbering in the hundreds, which are filled in one long pour from "a ladle which transports molten metal from a melting furnace. Such a process has an inherently limited yield because of the long passages by means of which the casting cavities in the mold are connected.

Various proposals for automatic casting machines utilizing single mold cavities indexed past a metal pouring stationhave proved unsatisfactorily especially for metals having high melting points such as ferrous metals. One problem has been to provide a completely satisfactory method of repeatedly metering precise amounts of a high melting point metal to successive molds. One difiiculty has been'designing valves of suitable refractory material which function reliably at elevated temperatures to measure accurately quantities of the order of a teaspoon full.

Accordingly, it is one object of the present invention to provide an improved casting machine for individually pouring castings from high melting point metals at a rapid rate.

Another object of the present invention is to provide an improved fully automatic casting apparatus especially one including a mechanicohydraulic motivator of the rotary cam and liquid column type, for metering successive quantities of different molten metals to each of a plurality of identical molds presented one after another.

Another object is to provide an improved bottompour casting furnace which prevents freezing and sticking of the poured metal around the valve apparatus or in the delivery passage.

'Still another object is to provide an improved valve apparatus which will not stick, and which will open the valve a precise amount, time after time, in pansion due to change in temperature.

spite of ex- 7 3,470,941 Patented Oct. 7, 1969 Another object of this invention is to provide an improved bottom-pour casting furnace including an oscillatory valve of refractory material connected to meter precise amounts through a novel delivery opening directly into a mold.

Another object of this invention is to provide an improved machine for placing a predetermined amount of one molten metal in a mold, allowing it to cool for a predetermined time, and then placing another predetermined amount of another molten metal in the same mold to produce a composite casting.

Further objects and advantages of the present invention will be apparent from the following detailed description, with reference to the accompanying drawings in which like reference characters refer to the same parts throughout the several views, and in which:

FIGURE 1 is a plan view of the supply furnaces for the casting machine of this invention;

FIGURE 2 is a diagrammatic cutaway elevational view of the supply furnaces for the casting machine;

FIGURE 3 is a diagrammatic fragmentary plan view of the index table supporting the molds and forming a part of the casting machine;

FIGURE 4 is a sectional elevational view of the index member showing the drive mechanism therefor;

FIGURE 5 is a sectional view on line 5-5 of FIGURE 4 showing further details of the drive for the index member;

FIGURE 6 is a view, partly in section and partly in elevation of the casting or pouring furnace of this invention;

FIGURE 7 is a perspective view of the linkage length compensator utilized by the valving apparatus of the casting furnace;

FIGULRE 8 is a sectional view on line 88 of FIG- URE 7 showing further details of the linkage length compensator;

' FIGURE 9 is an enlarged vertical section of the casting furnace showing the valve mechanism therein;

FIGURE 10 is a plan view with parts broken away showing the general scheme of the transfer arm loading means for the fresh molds;

FIGURE 11 is a vertical section of the mechanism for swinging and elevating a transfer arm;

FIGURE 12 is a sectional view on line 12-12 of FIGURE 11 showing the fluid motor for swinging a transfer arm;

FIGURE 13 is a diagrammatic plan view showing the general scheme of the transfer arm unloading means for the filled molds; and

FIGURE 14 is a view in schematic fashion showing the mechanicohydraulic motivator for both powering and controlling the casting machine of this invention.

Generally speaking, the machine may involve moving a mold and a pouring crucible relative to one another until the mold is near the crucible. Then, a predetermined amount of molten metal is metered from the crucible to the mold. Thereafter, the mold and the crucible are moved relative to one another to move the mold away from the crucible and present a new mold. In the casting of composite metal articles where separate metal charges must be introduced successively to the same mold, the mold is then moved to a second pouring furnace or crucible. Then a metered amount of a second molten metal is poured into the mold into contact with the first metal already in the mold. Means, including mechanism for regulating the rate of relative movement between the mold and the successive pouring furnaces, is provided to insure a predetermined time lapse between the introduction of the first and second molten metals to the mold. Furthermore, additional means are provided for keeping the various pouring furnaces filled with a desired amount of molten metal.

Novel valving mechanism associated with each of the pouring furnaces is provided to insure preclse, troublefree metering of predetermined small amounts of molten metal on a mass production basis.

To this end (see FIGS. 1, 2), the machine of this invention may include a shiftable member such as a unrtary rotary table 10 supported on a base or pedestal 12 located on a foundry floor. Small individual molds 14 (see FIG. 3), preferably of the shell mold variety, may be carried along an endless path around the periphery of the table in walled holders 16 extending laterally beyond the table edge and each secured to the table by locating pins 18 and a single bolt 19 through the side portion of the holder. Each holder 16 may further include a central aperture 20 to receive a locating boss (not shown) formed on the bottom of each mold. Each mold contains a casting cavity (not shown) of suitable shape. Such individual mold holders may be formed of brass to resist adhesion of stray amounts of molten ferrous metal, and each is readily detachable and replaceably as a separate individual unit without reconstruction of the entire table. A depending lip or rim 22 (FIG. 4) may further be secured to the edge of the table beneath the holders 16 to prevent stray molten metal from running along the underside of the table 10 and entering the indexing mechanism.

Beneath the table 10, an inner thrust bearing race 24 may be secured by fasteners 26, and the inner portion of the race may further include a ring of internal gear teeth 28. An outer bearing race 30 may be secured in a horizontal plane to the base 12 by fasteners 32 in position to retain ball bearings 34 and thus support the table 10'for rotary motion.

Drive mechanism for the table may include a pinion 36 meshing with the gear teeth 28 of the table and driven by a shaft 38 which also forms the rod of a double-acting piston 40 both axially and rotationally shiftable within a cylinder 42 formed in the base 12 of the indexing member. Elongated pinion teeth 44 on the periphery of the piston between the oppositely facing U cup seals 46 are engaged by the teeth 48 of a rack 50 shiftable to and fro tangentially of the piston 40 within a second cylinder 52 (FIG. Hydraulic fluid under pressure, herein called return oil, admitted to the upper end of the cylinder 42 through a connection 54 constantly urges the piston 40 downwardly toward a position disengaging the pinion 36 from the gear 28 so that the rack 50 may be reset. Hydraulic fluid at a higher pressure, admitted to the lower end of cylinder 42 through a connection 56, overcomes the return oil pressure and shifts the piston 40 upwardly within its cylinder to engage the drive pinion 36 with the gear 28. Likewise, return oil under pressure admitted to one end of the second cylinder 52 through a connection 58 shifts the rack 50 to one end of its cylinder. Hydraulic fluid pulsed at higher pressure to the other end of the cylinder 52 through a connection 60 shifts the rack in the other direction to turn the elongated pinion teeth 44, to drive the pinion 36.

When the table has been indexed through the distance between centers of adjacent holders 16 and the drive pinion 36 is lowered so that the rack 50 may be reset, the table is located and locked by the apparatus shown in FIG. 4. Such a device may include a gear tooth 62 secured to the rod 64 of a piston 66 axially shiftable in a cylinder 68. Return oil admitted to the cylinder 68 through a connection 70 retracts the piston 66 and allows rotary motion of the table 10. Hydraulic control fluid admitted to the other end of the cylinder 68 through a connection 72 shifts the piston 66 to engage the gear tooth 62 with a tooth of the ring of gear teeth 28 on the table. This accurately locates and locks the table in position while metal is being poured into one of the molds 14, and while the drive gear 36 is lowered for resetting.

Positioned around the table 10 on the foundry floor, in addition to a mold holder cleanout station including an air blast nozzle 73 (FIG. 3), may be a plurality of metal pouring stations. Two

such stations

74 and 76 are shown in FIGURE 1. Since both stations may be composed of similar elements, description of station 74 will provide a disclosure of both, structural elements of the pouring station 76 will be designated by similar reference numerals with the addition of a prime mark.

A pouring station may comprise a pouring or casting furnace 80, a holding and transfer furnace 82, and a melting and alloying furnace 84 spaced from the index table along a generally radial line. The melting furnace 84 may be a conventional induction heating unit tiltable by means of an overhead lift connection 86 about trunnions 88 to transfer molten metal from the metal containing portion 90 to the transferring and holding furnace 82. Each holding furnace 82 may comprise a similar induction coil heating unit including a metal containing pot 92 with a pouring spout 94 of conventional design. The supports 96 for the trunnions 98, however, are formed as upstanding side parts of a dolly 100 (see FIG. 2) having wheels 102 rollable in upper and lower confining trackways 104. The trackways 104 extend from the melting furnace 84 to the pouring furnace 80.

As can be seen from FIGURE 2, the pouring furnace 80 is located above the rotary table 10, and the trackways 104 are positioned on a stepped floor section of the foundry to locate the pouring spout 94 of the holding furnace 82 at the desired elevation to transfer molten metal from the pot 92 to the casting furnace 80. Similarly, at the other end of the trackway 104, the melting furnace 84 is located on another stepped floor section of the foundry at an elevation whereby metal may be poured from its pot 90 to the pot 92 of the holding furnace 82. Thus, metal melted and alloyed in the furnace 84 may be transferred to the holding furnace 82, which in turn may traverse the trackways to the pouring furnace 80 to keep the latter relatively small furnace filled with the desired amount of molten metal. If desired, in place of an overhead hoist type tilting mechanism, a rotary tilt motor 106 may be mounted on the trunnion support 96 of the traversing furnace structure to swing an arm 108 having a slot and pin connection 110 with the bottom of the furnace 82.

The casting furnace 80 (FIGS. 6, 9) may comprise a helical electric induction heating coil 112 concentrically surrounding a cylindrical container 114 separated therefrom by a centering and insulating layer of packed casting sand 116. The container 114 and heating arrangement 112 may be supported upon suitable slabs of refractory or ceramic material located upon a framework 118, and may be separately replaceable as a unit on the framework to exchange one such furnace for another of different characteristics required for casting, for instance, of a different article. A split disc-shaped cover 119 may be utilized across the top of the container.

In addition the framework 118 supports actuating mechanism for valving arrangements constructed to meter predetermined small amounts of molten metal from the casting furnaces to a mold 14 positioned on the table. Such a valving mechanism may comprise an elongated shiftable valve member 120 (FIGS. 6, 9) of refractory ceramic material having a semispherical bottom end portion 122 extending down into the container 114, and an upper portion 124 extending above the container 114. An actuating lever 126 of the first class pivoted at 128 on the framework 118 may be pivotally connected at 130 with the upper portion 124 of the valve. Oscillation of the lever 126 in a vertical plane about its pivot axis 128 will raise and lower the valve. Such motion may be effected by a fluid motor 132 fixed on the framework 118 having an upper connection 134 through which bydraulic medium may be pulsed to lift the valve 120, and a lower connection 136 through which return oil may be conducted continuously to urge the valve downwardly in the container 114.

Connecting the lever 126 with the piston rod 138 of the fluid motor 132 is a compensating mechanism 140 to automatically adjust the valve actuating linkage to accommodate thermal expansion or contraction of the elongated valve rod member 120 orparts of the linltage. One form of such a compensator may comprise a housing 142 (FIGS. 7, 8) including external pivot connections 114 with the lever 126, and a central aperture 146' for a piston rod extending in a direction normal to the axis of the pivot connection 144. A compressible sleeve 148 may be located within the aperture 146, and may be formed by longitudinal-slots 150 in an elastic metal sleeve having a relaxed, normal internal diameter only slightly larger than the diameter of the piston rod 138 of the fluid motor 132. A plunger 152 in a laterally extending section 154 of the housing 142 of the compensator may radially abut the. slit end of the sleeve 148. Hydraulic fluid pulsed througha connection 156 in the end of the housing portion 154 serves to hold the plunger 152 laterally against the resilient sleeve 148 and thus clamp the piston rod 138 in fixed relation to the lever pivot 144. When the .valve is closed, and the fluid motor 132 is in its rest position, fluid pressure may be relieved from be.- hind the plunger 152 to let the split sleeve 148 expand and release the connection between the rod .138 'and housing 142 to allow an automatic sliding compensating adjustment of the connection between the lever pivot 144 and the piston rod 138.

A valve seating spring 158, the tension of which may be adjusted by a nut 160 on the piston rod 138, holds the valve 120 closed, with desired downwardseating pressure when the valve is not being held open by the fluid motor ,132. Y Y

'The lower rounded end 122 of the valve 120 below the level of the molten metal in the container 114 mates with an upwardly facing dished valve seat .162 formed in an annular support 164 (FIG. 9) also of refractory ceramic material similar to that in the valve. The support 164 may include an outer shoulder 166 separating larger andsmaller outer circular portions thereof. The smaller circular portion may be snugly received in an aperture 168in thebottom wall of the container 114 and its supporting, structure, and ;the larger portion mayext'endupwardly, to position the valve seat 162 awayfrom the containerwall whereby molten metal and the field of the induction coil 114 will essentially surround the valve and its'seat. v.

- The-metal pouring passage in the member 164 includes a port172 of relatively small diameter, selected to control the pouring of metal at the desired rate. The port 172 leads from valve seat 162 to an abrupt edge 176 within a passage 174 of large diameter, which in turn leads'to a mold 14. Preferably the upper end of the large passage 174 overlaps the lower end of the small passage 172 so that the abrupt edge 176 is on a lip which projects some distance into the large passageI-Iowever some advantages of theinvention may be achieved without this overlap as long as the corner between 172 and 176 issharp. This is especially the case Where there is a sufiicient head of molten metal to project a clean stream past the edge, even though the surfaces are not reversed as in FIG. 9.

For .example the lip, as shown in FIG. 9, includes a narrow annulus perpendicular to the passage 172. This annulus extends toward the wall 174 in a plane perpendicular to. the wall of passage 174. The annulus may extend all theway to the wall of passage 174.

This arrangement delivers molten metal into the free space in passage 174 out of contact with, and remote from, the wall of that passage. While the edge, whether its sharp corner is or is not on a projecting lip as shown in FIG. 9, tends to reduce or eliminate spatter, the passage 174 should be large enough to prevent any spatter reaching thewalls of the passage. As a practical matter the diameter of the passage should be as large as it can be without reducing the heating efiect of the molten metal on the passage 172. The larger the diameter of passage 174, the longer is the heat conducting path through the member 164 from the molten metal to the passage 172. This path must be maintained short enough to insure maintenance of adequate temperature of the walls of passage 172.

In the arrangement of the support 164 just described, because the valve tip and seat are completely within the field of the heating coil 112 and are completely surrounded with molten metal, this has the additional advantage of preventing sticking of the valve when the furnace is first operated.

For one reason which I do not understand, when a refractory ceramic valve and a seat of similar material are used, with ferrous metals at least, it sometimes happens that molten metal gets into the space between the valve and seat before the metal is hot enough to pour. At this particular temperature, this forms an adhesive which appears to be a reaction product of the ceramic and the ferous metal at a particular range of temperatures. This prevents satisfactory operation of the valve. But when the adhered valve is exposed sufficiently long to molten metal at the proper temperature, the adhesive quality of any byproduct seems to disappear and the valve can be satis factorily operated. Because the seat is surrounded by molten'metal and by the field of the heating coil I believe this adhesion is less likely to happen, is not as severe when it does occur, and is more readily and quickly eliminated, than is the case with other arrangements of valve and seat.

The entire support 164 including the delivery opening and valve seat may be formed as a replaceable insert whereby a new unit may be substituted for a worn one with very little effort. Furthermore, since the size of the delivery opening 172 governs the rate of flow from the container 114-viscosity and static head remaining constant-the amount of metal metered in a given time may be varied simply by replacing valve seat inserts 164 with those having the desired orifice size for the particular metal being cast. A second opening 178 in the container bottom spaced from the delivery opening may be plugged by suitable snug fitting closure means 180, removeable to drain the pot 114 of casting material without removal of the valve seat support 164.

For loading and unloading the mold 14 to and from the holders 16 on the shiftable member 10', a pair of

transfer arms

184, 186 may be provided, as shown in FIG. 1 one at a first station ahead of the plurality of pouring stations and one at a final station following the series of pouring stations. The loading means 184 at the first station isillustrated in FIGURE 10; the unloading means .186 at the final station is illustrated in FIGURE 13. Each means may comprise horizontally swinging transfer arms with a gripper at the outer end and an elevating mechanism at the pivot, and they may be identical in structure differing only in operation characteristics of moving parts-thus, detailed description of one will suffice to disclose the structure of both.

As can be seen in FIGURES lO-l3, such a transfer arm may comprise a generally horizontally extending swinging body member 188 fixed at one end on a vertical pivot shaft 190 which is journalled in and axially shiftable through suitable bearings 191 in the machine base. Pinion teeth 192 integral with the pivot shaft are engaged by the teeth of a rack 193 shiftable normal thereto. A pair of U-cup sealed piston faces 194 on either end of the rack 193 reciprocate in aligned cylinders 195 to shift the rack to-and-fro between adjustable limit stops 196. Return oil admitted through a connection 197 swings the arm away from the index member 10, and pulsator fluid admitted through a connection 198 swings the arm in the opposite direction towards the index member 10, as can be understood.

The lower end of the arm pivot shaft 190 (FIG. 11) has a swivel connection 199 with the upper end of the rod 200 of a piston 201 vertically reciprocable in a cylinder 202 in the machine base. Return oil admitted to the cylinder 202 through a connection 203 biases the shaft downwardly on the machine base, and hydraulic medium admitted through a connection 204 elevates the shaft '190 and consequently lifts the arm 188 bodily upward a predetermined distance. It will be noted that the pinion teeth 192 are axially elongated so as to retain their meshing engagement with the rack 193 as the arm is raised and lowered.

On the outer end of such a transfer arm, a pair of gripper jaws 205 are shiftable in opposition to one another along the arm axis. They shift in unison by means of a double rack and central pinion assembly 206 housed in the arm itself. Double piston cylinder arrangement 207 in the arm serves to close the jaws when subjected to hydraulic pressure through a connection 208, and open the jaws when subjected to hydraulic pressure through a connection 209.

The transfer arms, as well as the other fluid motors discussed above, may be operated by the mechanicohydraulic motivator (explained in detail below) in the following fashion. First, the jaws of the loading arm 184 close to grip a fresh shell mold 14 at a supply station, illustrated in FIGS. 1, 10, continuously replenished with fresh molds by suitable means such as an endless belt. Then the loading arm is raised to lift the mold clear of guide rails at the supply station and other molds previously loaded on the table 10 so that it may swing clockwise to position the gripped mold over a holder 16 on the table 10 presented at the loading station, as indicated in phantom lines in FIG. 10. Lowering of the arm and subsequent opening of the jaws serves to deposit the mold on the index member, which may begin its next indexing movement prior to the arm again lifting and then swinging counterclockwise back to the mold supply station.

The unloading arms 186 (FIGURE 13) may move through a somewhat similar cycle. As a filled mold is indexed by the member 10 to the unloading station, the jaws of the unloading arm close to grip the mold, crunching through any loose sand, if necessary, and engaging the cooling casting itself. Then, the arm will raise bodily, lifting the casting clear of the fixture 16, free to swing counterclockwise to a position above a step-by-step cooling conveyor. After lowering of the arm, the jaws may open and allow the workpiece to be deposited upon the cooling conveyor which, after the arm is again raised, moves the casting toward a gate removal operation. Thus, the loading and unloading means, identical in structure, follow similar programs to render the casting machine of this invention entirely automatic and well suited to modcm high valume, mass production requirements.

For the purpose of giving coordinated motivation to the various fluid motors described above, there is provided a mechanicohydraulic programming system for producing a cycle of cooridnated movement, illustrated diagrammatically in FIGURE 14. This system may be constructed as a self-contained unit having its own housing, not illustrated, which may be positioned at any convenient location on or adjacent the machine and connected to the various hydraulic cylinders by suitable flexible piping. The mechanicohydraulic drive unit comprises a master camshaft 236 carrying a plurality of cams 238, the followers of which operate the transmitter pistons 240, each of which forms part of a liquid column type motion transfer device of which there are ten units shown in the diagram of FIGURE 14. Each piston reciprocates in a cylinder 242 having a head B which contains a suitable inlet replenishing check valve 308 and a high pressure relief valve 310 both of which communicate with a low pressure oil reservoir 312 preferably formed in a housing enclosing the drive unit.

For turning the camshaft 236, a motor 246 drives an input shaft 248 of the two-speed transmission through a belt drive 250. The input shaft 248 drives a pinion 252 and also the input member of a hydraulically-engaged, spring-released clutch 254. Pinion 252 drives a gear 256 secured to a countershaft 258 which carries a pinion 260 at its opposite end. Pinion 260 drives a gear 262 and therewith constitutes a set of change speed gears. Gear 262 drives the input member of a second hydraulically engaged, spring-released clutch 264. The driven members of clutches 254 and 264 are secured to the opposite ends of a shaft 266, having a worm 268 thereon and brake drum 270. The latter has a spring-biased hydraulic motor 272 for engaging the brake. Worm 268 drives a worm wheel 274 secured to the master camshaft 236.

For the purpose of automatically controlling the starting, stopping, and speed of the transmission, there is provided a hydraulic control pump 276 driven from gear 262, which may circulate a body of oil contained in the housing surrounding the transmission. The pump 276 may deliver to a combined accumulator and relief valve comprising a spring loaded piston 278 and also supplies oil to a bank of

control valves

280, 282 and 284. In the diagrams, each valve is shown as a two-position valve, spring-biased to the position illustrated in which the connections shown in the cross-hatched rectangles are established. Single-headed arrows are used to indicate flow at reservoir pressure and double-headed arrows to indicate flow at pump delivery pressure. Each of the valves, when shifted, establishes the connections shown in the unhatched rectangles immediately below the hatched rectangles.

Valve 280 is arranged to be shifted by a solenoid 286. Valves 282 and 284 are arranged to be shifted by the

adjustable cams

288 and 290, respectively, which are positioned on camshaft 236. In addition, the valve 282 has a hydraulic holding cylinder 292 which holds the valve 282 in its shifted position unitl it is released by the shifting of valve 284. Valve 280 in the position shown delivers pressure fluid to engage the brake 272 and also exhausts fluid to release the low speed 264. When shifted, valve 280 exhausts fluid to release brake 272 and supplies pressure fluid to engage the low speed clutch 264, subject, however, to a conjoint control by the valve 282.

The latter valve, in the position illustrated, exhausts fluid at release the high speed clutch 254 and places the low speed clutch 264 under the control of valve 280. In its shifted position, valve 282, provided valve 280 has been shifted, delivers pressure fluid to engage high speed clutch 254 and exhausts fluid to release low speed clutch 264. As previously explained, the valve 284 is merely a reset valve for bypassing the holding cylinder 292 to permit valve 282 to return to its spring biased position shown in the drawings.

Thus, energization of solenoid 286 will start the camshaft rotating at slow speed. Thereafter, the cam 288 will shift the transmission to drive the camshaft at high speed, and still later the cam 290 will again shift the transmission to slow speed. So long as the solenoid 286 remains energized, the camshift 236 will continue to rotate, first at a slow speed and then at a high speed during each revolution, controlling its own speed changes by operation of the

cams

288 and 290.

For the purpose of controlling the drive motor 246 and solenoid 286, there is provided an electric control circuit connected between a pair of electric supply lines, designated L1 and L2. The circuit may include a master relay 294 of the holding type having a manual master start switch 296 and a manual master stop switch 298. Relay 294 controls the motor 246 and also a cycle control relay 300 of the holding type having a manual cycle start switch 302 and a manual cycle stop switch 304. The normally open contacts of relay 300, which are of the makebefore-break type, control energization of cycle solenoid 286 directly. The normally closed contacts of relay 300 also control solenoid 286, but are in series with a cam switch 306 on the end of the camshaft 236 and arranged to be opened once during each revolution thereof. The arrangement is such that when the cycle stop switch 304 is operated at any point in the rotation of camshaft 236, relay 300 will be de-energized, but solenoid 286 will remain energized until cam switch 306 opens at the predetermined stopping point. Operation of the master stop switch 298, however, will de-energize solenoid 286 immediately, regardless of the point in the cycle and will also de-energize motor 246.

The camshaft 236 as previously mentioned drives a number of cam operated hydraulic pulsator sections designated a through i, inclusive. Each section may comprise units duplicating the single acting pulsating cylinder 242, the head B of which contains the replenishing check valve 308 and the spring closed relief valve 310. All the replenishing and relief valves are connected to a common'oil reservoir 312 formed in the housing of the unit. The reservoir 312 is preferably subjected to a low, super-atmospheric pressure by a body of compressed air or other pressure maintaining arrangements. Check valves 308 allow flow from the-reservoir 312 to the cylinder 242, while relief valves 310 allow flow oppositely when the cylinder pressure exceeds a certain value. Thus each of the pair of

valves

308 and 310 may be referred to as a balancing valve and serve to balance the volume of fluid in each of the liquid column sections.

In order to insure proper synchronization of the driving and driven elements of each pulsator section, it is desirable to provide slightly more fluid displacement in the driving ortransmitting elements 240-242 than is present in their respective fluid motors at the opposite end of the liquid column line. Thus at the end of each advancing stroke of the transmitter piston 240, a small amount of fluid will be discharged to reservoir 312 through its relief valve 310. This amount plus any amount lost by leakage will be returned to the liquid column at the end of the return stroke by the operation of the replenishing valve 308.

In FIGURE 14 there are shown'several circles marked R connected to the end of some of the motive cylinders opposite the liquid column connections. These symbols designate the return oil connections by means of. which a pulsator system may be hydraulically biased so as to maintain the follower in close contact withthe cam as the falling portion of the cam contour recedes from the follower. This bias is maintained by a high pressure accumulator or oil reservoir, not shown, which may be provided with a manifold whereby all of the R0 connections are joined together and to the high pressure reservoir. The showing of separate return oil connections in FIGURE 14 is indicative of any suitable type of biasing pressure source, whether it be a single accumulator or multiplicity thereof. The contours of the individual cams 238 are likewise not illustrated in specific detail since they may be formed in accordance with the usual practice to cause motivation of each of the respective hydraulic motors in accordance with the particular operating cycle desired for the machine. Likewise the speed ratio between the high and low speeds of the camshaft 236, and the duration of the high speed portion of the cycle, may be selected as desired through use of the appropriate change gears 260-262 and through the adjustment of the

cams

288 and 290, if desired. Of course, the two speed feature of the transmission may be omitted and the high speed clutch 254, the

cams

288 and 290 and the valves 282 and 284 eliminated.

As can be seen from FIGURE 14, the pulsator section a is connected by a closed liquid column line 314a with the connection 204 of the fluid motor for raising and lowering the loading arm. The pulsator section b is connected by a closed liquid column line 314b with the connection 72 of the fluid motor which operates the locking and holding finger 62 for the index table. The pulsator section c is connected by a closed liquid column line 3140 with the connection 198 of the fluid motor which swings the loading arm. The pulsator section d is connected by a closed liquid column line 314d with the connection 56 ofthe fluid motor which raises and lowers the drive pinion 36 for indexing a shiftable table 10.

The pulsator section e is connected by a closed liquidcolumn line 314e with the connection 209 of the fluid motor for operating the gripper jaws 205 of the loading arm. The pulsator section 1 is connected by a closed liquid column line 314] with the connection 134 of the fluid motor 132 which operates the metal metering valve at the pouring station 74. The pulsator section g is connected by a closed liquid column line 314g with the connection 134' of the fluid motor 132 which operates the metal metering valve at the pouring station 76. The pulsator section it is connected by a closed liquid column line 314k with the connection 156 to operate the clamping plunger 152 of the compensating mechanism 140 for the metal metering mechanism at the pouring station 74. The pulsator section i is connected by a closed liquid column line 314i with the connection 60 of the fluid motor which operates the rack 50 to index the table drive pinion 36. The pulsator section j is connected by a closed liquid column line 314 with the connection 156 to operate the clamping plunger of the compensating mechanism 140' for the metal metering mechanism at the pouring station 76. At least three additional pulsator sections (not shown) may be provided to operate further fluid motors to control the unloading arm 186, and the like.

It will be noted from FIGURE 14 that liquid column lines 314]- and 314g are interrupted by three-way, two position solenoid actuated

valves

316 and 318, respectively, spring-biased to their normal positions in which the connections shown in the cross-hatched rectangles are established. These are liquid column disabling valves which, in the normal position shown, allow free operation of the liquid columns but, in the shifted position, establish the connections shown in the unhatched rectangles whereby the liquid columns are directly connected, or dumped, into the low pressure reservoir 312 thus allowing the fluid motors 132 and 132' to return to their normal positions responsive to the return bias from the source R0. This closes the metal metering valves at the pouring stations even though the cams at pulsator sections f and g still present rise contours to their respective followers.

The

valves

316 and 318 are each moved to their shifted position by timing

mechanisms

320 and 322, respectively, individually adjustable to determine the length of time the metal metering valves are opened, and thus governing the amount of metal metered to the molds at each of the pouring stations. Each timer is started during every cycle of the machine by suitable electric circuitry of conventional design responsive to a rotary cam activated limit switch 324. As each-timer times out and actuates the solenoid after the metal metering valve has been opened by the cam at pulsator sections f or g, the liquid column is disabled and the valve is closed at the adjustable, predetermined time dictated by the timer. Later in the cycle, after the pulsator cams at these stations have again presented their base circles to their followers, a second cam operated limit switch 326 may be employed to reset the two timers and deactivate the solenoids. If desired, of course, the fine adjustment provided by the timers may be eliminated, and the metal metering valves may be controlled directly by the cams at the respective pulsator sections.

In operation, the casting machine of this invention works through repetitive cycles of coordinated motion programmed by the mechanicohydraulic motivator. With the casting furnace at the pouring station 74 filled with one variety of molten metal, and the casting furnace 80 at the pouring station 76 filled with a different variety of molten metal, operation of the machine may commence. As noted above, fresh empty shell molds 14 are loaded to the holders 16 on the indexing member 10 by means of the loading arm 184. This arm first grips the mold with the jaws 205 under control of motivator station e, then raises bodily under control of motivator section a, and then swings horizontally under control of motivator section 0. After the mold is positioned above a newly presented empty holder 16 on the table, the arm lowers under control of the motivator section a and the jaws 205 open responsive to motivator section e to thus deposit a fresh mold on the table. Thereafter the arm may raise and then swing back to the supply station to get another fresh mold. During this time, the unloading arm 186 is going through its above-noted cycle under control of three similar pulsator stations (not shown) to remove filled molds from the holders 16 on the opopsite side of table and deposit them on the removal conveyor for further cooling.

While the loading and unloading arms are not Working directly over the table 10, it may be indexed by raising the drive pinion 36 under control of motivator section d to engage the table gear teeth, and then imparting rotary motion to the table via the pinion 36 by shifting the rack 50 under control of motivator section i. After an indexing movement is complete, the drive pinon 36 is lowered under control of the motivator section d so that the rack 50 may be reset by the falling cam face at motivator section i.

When the index table 10 is stopped, the locating and locking finger 62 under control of motivator section b holds the table in its newly indexed position While the index drive is being reset, the loading and unloading arms are working over the table, and the metal metering valves at the various pouring

stations

74, 76 are operated to deliver a predetermined amount of molten metal from the respective casting furnaces to the mold juxtaposed thereto.

To meter metal, the valve rod 120 in the casting furnace is raised slightly from its dished seat 162 by the fluid motor 132 controlled from motivator section 1 of the mechanicohydraulic motivator. While the valve rod 120 is off its seat, metal pressurized by the static head of molten metal in the pot 114 flows across the seat 162 and out the outlet opening 172 of the valve mechanism and then flows by gravity directly into the mold 14. With a given viscosity to the molten metal, a given size to the orifice 172, and a static head of metal within allowable tolerances, the quantity of metal metered from the casting furnace to the mold may be very accurately controlled by the amount of time the valve 120 is held off its seat by the mechanicohydraulic motivator. The valve may be closed by operation of the timer controlled solenoid valve 316 for disabling the liquid column 3149 which actuates the fluid motor 132. Thus, it will be clear that the head or amount of metal in the casting pot 114 is maintained at or near a desired level for product continuity. To this end, the reserve furnace 82 is employed which receives molten metal from the melting furnace 84, traverses the trackway 104 to the pouring furnace, and then tilts to transfer desired amounts of molten metal to the pouring furnace 80. While the metal metering valve at pouring station 74 is operating, the valve at pouring station 76 is also operated to meter metal to a mold juxtapositioned therebeneath by the table 10.

As a given or particular fresh mold, after being loaded on the table, is indexed beneath the casting furnace 80 at the first pouring station 74, a predetermined amount of a certain molten metal is metered thereto. The metal flows by gravity to the bottom of the mold cavity and assumes the position it is to occupy in the finished article. Thereafter, the partially filled mold is indexed by the table through several cycles as the molds following it also receive their initial amount of the first molten metal. Eventually, after a predetermined time has elapsed which is governed by the distance between the pouring

stations

74 and 76, by the spacing of the mold holders 14 from one another on the table periphery, and by the table speed and distance of index, the given mold partially filled with metal is indexed beneath the pouring furnace at station 76. Here, the mold cavity receives an additional amount of a different molten metal which flows into the mold on top of the previously introduced metal, and fills the mold to thus complete the casting process. Further indexing motions of the table bring the given mold to the unloading station, where the unloading arm deposits it upon the removal conveyor to transport it to a gate removal operation.

It will, of course, be obvious that if so desired, the second pouring station 76 may be rendered inoperative and articles cast solely of one metal may be produced by the casting machine of this invention. Conversely, more than two metal pouring stations may be provided about the table periphery to produce multimetal castings utilizing three or more separate varieties of metal.

Thus a casting machine has been disclosed that is readily adaptable to a number of casting problems. Notably, composite casting of multi-metal articles is rendered commercially feasible due to such improved structure including the metal metering arrangement suitable for high melting temperature metals.

While the above described embodiment constitutes a preferred mode of carrying out this invention, many other forms might be adopted within the scope of the actual invention, which is variously claimed as:

1. Apparatus for automatically casting small metal articles sequentially comprising in combination indexing means, a plurality of mold holders spaced on the means, drive means connected to shift the indexing means to move the holders along a path, a bottom-pour furnace for molten metal positioned at one location above the path, a melting furnace for metal positioned remote therefrom, a portable holding furnace for transferring molten metal from the melting furnace to the bottompour furnace, and the drive means further including valving means for intermittently pouring predetermined amounts of molten metal from the bottom-pour furnace.

2. Apparatus for automatically casting small composite articles of plural metals sequentially comprising in combination indexing means, a plurality of mold holders spaced around the means, drive means connected to shift the indexing means to move the holders along a path, first and second bottom pour furnaces for different molten metals positioned at spaced locations above the path, first and second melting furnaces for the dilferent metals both positioned remote from the bottom pour furnaces and from each other, and first and second portable holding furnaces for transferring molten metals from the respective melting furnaces to the respective bottom-pour furnaces, the drive means including valving means for intermittently pouring a predetermined amount of a first molten metal from the first bottom pour furnace into a given mold, second valving means for pouring a predetermined quantity of a second metal from the second bottom-pour furnace into the same mold and means for providing and measuring a predetermined time interval between the pourings of the two metals.

3. Apparatus for automatically casting small composite metal articles sequentially comprising in combination a table shiftable past a plurality of spaced stations, a plurality of mold holders at spaced locations on the table, a separate container of molten metal at each station, the metal in one container being different from the metal in another container, heating means associated with each container to maintain the contained metal molten, valving means associated with each container and including a seat within the container, a delivery passage wider at the bottom than at the top downwardly directed from the seat through the container bottom toward an adjacently positioned mold holder, a valve member shiftable relative to the seat, motor means for shifting the valve member relative to the seat, linkage means connecting the motor means with the valve member, compensating means connected to 13 adjust the effective length of the linkage means, drive means connected to shift the table member step-by-step, and a common programming system connected to synchronize the drive means 'with the motor means at each of the spaced stations.

4. Casting apparatus comprising in combination a container to hold molten metal, a heating source for maintaining the metal molten in the container, a valve within the container, a seat for the valve located away from the container walls so that the seat is generally surrounded by molten metal, and a delivery space wider at the bottom than at the top to preclude metal freezingthereindirected substantially vertically downwardly from the seat for delivering molten metal from the container, said delivery space including a first passage extending downwardly from the seat into a second and wider passage, the first and relatively narrow passage being joined to the second and wider passage by a lip surrounding the first passage and projecting into and spaced from the second passage.

5. Casting apparatus comprising in combination a container to hold molten metal, a heating source for maintaining the metal molten in the container, a valving mechanism in the container, a generally vertical passage extending downwardly from the valving mechanism through the container wall, replaceable tubular insert means of refractory material received within the passage to form a discharge opening, the insert means having a wider internal dimension at the bottom than at the top and having a reverse angle shoulder therein forming an overhanging internal lip located in the upper portion thereof in the range of the elevated temperature.

6. Casting apparatus comprising in combination a container to hold molten metal, valving mechanism including a valve member seated in the container and having a portion extending upwardly above the confines of the container, a lever connected with the valve member above the container and pivoted about a horizontal axis fixed in relation to the container, oscillating motor means connected to actuate the lever to impart generally up and down movement to the valve member relative to the container, and compensating means connected between the motor means and the lever to automatically adjust for dimensional variations of the valving mechanism to insure proper seating of the valve member in the container.

7. Casting apparatus comprising in combination a container to hold molten metal, valving mechanism including a valve member seated in the container and having a portion extending upwardly above the container, lever means connected with the valve member above the container and pivoted about a horizontal axis fixed in relation to the container, yieldable biasing means connected to urge the valve member into seating position, fluid motor means connected to actuate the lever means to impart generally up and down movement to the valve member relative to the container, compensating means between the motor means and the valve member connected to automatically adjust for dimensional variation of the valving mechanism to insure proper seating of the valve member, and a mechanicohydraulic motivator of the rotary cam powered and controlled liquid column motion transfer type connected to operate the fluid motor means through a predetermined operational sequence.

8. Casting apparatus comprising in combination a container for molten metal, a valve seat in the container and within the molten metal, a valve cooperating with the seat and extending above the container, a motor adapted to be held in either of two extreme positions and connected to the valve above the container for raising the valve from the seat and for lowering the valve against the seat, and compensating means connected between the motor and the valve to vary the relative positions of the motor and valve to assure constant positioning of the valve relative to the seat whenever the motor is in either of its extreme positions regardless of variations in the dimensions of parts of the apparatus.

9. Casting apparatus comprising in combination a container for molten metal, a valve seat in the container and within the molten metaL'a valve cooperating with the seat and extending above the container, a motor adapted to be held in either of two extreme positions and connected to the valve above the container for raising the valve from the seat and for lowering the valve against the seat, compensating means connectedbetween the motor and the valve to vary the relative positions of the motor and valve to assure constant positioning of the valve relative to the seat whenever the motor is in either of its extreme positions regardless of variations in the dimensions of parts of the apparatus, and means for preventing operation of the compensating means when the motor holds the valve open, said last mentioned means permitting operation of the compensating means when the motor holds the valve closed.

10. Casting apparatus comprising in combination a container for molten metal, a valve seat in the container and within the molten metal, a valve cooperating with the seat and extending above the container, a motor adapted to be held in either of two extreme positions and connected to the valve above the container for raising the valve from the seat and for lowering the valve against the seat, compensating means connected between the motor and the valve to vary the relative positions of the motor and valve to assure constant positioning of the valve relative to the seat whenever the motor is in either of its extreme positions regardless of variations in the dimensions of parts of the apparatus, and a second motor for at times preventing the operation of the compensating means.

11. Casting apparatus comprising in combination a container for molten metal, a valve seat in the container and within the moten metal, a valve cooperating with the seat and extending above the container, a motor adapted to be held in either of two extreme positions and connected to the valve above the container for raising the valve from the seat and for lowering the valve against the seat, compensating means connected between the motor and the valve to vary the relative positions of the motor and valve to assure constant positioning of the valve relative to the seat whenever the motor is in either of its extreme positions regardless of variations in the dimensions of parts of the apparatus, a second motor for at times preventing the operation of the compensating means and means for operating the second motor when the first motor holds the valve oil the seat.

12. Casting apparatus comprising in combination a container for molten metal, a valve seat in the container and within the molten metal, valve means cooperating with the seat and extending above the container, motor means adapted to be held in either of two extreme positions, a connection between the motor means and the valve means above the container for raising the valve from the seat and for lowering the valve against the seat, said connection including a movable rod, a housing surrounding the rod and connected to one of said means, the rod being connected to the other of said means, and means for releasably fixing the housing with respect to the rod to assure constant positioning of the valve relative to the seat whenever the motor is in either of its extreme positions regardless of variations in the dimensions of parts of the apparatus.

13. Casting apparatus comprising in combination a container to hold molten metal, a heating source for maintaining the metal molten in the container, a valve within the container, a seat for the valve located away from the container walls so that the seat is generally surrounded by molten metal, and a straight vertical unobstructed delivery space wider at the bottom than at the top to preclude metal freezing therein directed downwardly from the seat to a place near the mold for delivering molten metal from the container into the mold, said delivery space including a first passage extending downwardly from References Cited UNITED STATES PATENTS OTHER REFERENCES The Making, Shaping and Treating of Steel, United States Steel Corporation, 1957, page 493.

Nocheck "164-32 I. SPENCER OVERHOLSER, Primary Examiner g :g$ l 7; R. SPENCER ANNEAR, Assistant Examiner Wills 3222 566 Reinartz et a1 164.3-37 1 U'S' CL X'R' Summey 16 E327 XR 5 1 1 3 326; 22 -510 Summey 164,.251