US2238046A

US2238046A - Casting machine

Info

Publication number: US2238046A
Application number: US222737A
Authority: US
Inventors: Donald H Garth
Original assignee: Individual
Current assignee: Individual
Priority date: 1938-08-03
Filing date: 1938-08-03
Publication date: 1941-04-15
Anticipated expiration: 1958-04-15

Description

CASTING MACHINE Filed Aug. 3. 1938 D. H. GARTH CASTING MACHINE April 15, 1941.

Filed Aug. 5, 1938 E5 mwwW-Smm 2 D. H. GARTH CASTING MACHINE Filed Aug. 3, 1938 m Shwwts-Shewt 3 Jhwni or W W 41mm Patented Apr. 15, 1941 UNITED STATES PATENT OFFICE astfil itllm Donald H. Garth, Chicago, Ill. Application Am #1938, Serial N0. 222,737

(Cl. 2H7) 8Claims.

This invention relates to a casting machine.

The particular embodiment which I shall herein illustrate and describe is a machine for die casting metal objects.

One of the main objects of the invention is to provide a casting machine which is operable expeditiously to provide a plurality of good castings of the same shape or in diflerent shapes at the same time, and a machine in which an variation in the shapes of any number or all the plurality of castings produced at the same time may be readily accomplished.

It is a further Object to reduce or substantially eliminate heat loss from the molten metal in its delivery from the molten metal container through the gate and runner means to the mold means, so as to prevent chilling or solidification of the molten metal in the gate or runner means or elsewhere in its passage to the mold means, and to assure that the molten metal is delivered into the mold means in the desired molten condition completely to 1111 the mold means and produce good homogeneous castings at all times.

The maintenance of the metal in molten condition in its passage through the gate and runner means eliminates cleaning of gates and runners from the finished work and clogging of the metal in its passage to the mold means. The master mold plates are preferably arranged so that the molten metal will drain from the runners and gates when the mold plates are parted, and the base section of the machine is preferably formed to hold a removable tray or crucible for catching the overflow or waste metal in operation.

It is a further object of the invention to provide an improved displacement method of delivering the molten metal from the molten metal container to the mold means. In the illustrated embodiment, this displacement method; in conjunction with the arrangement oi the mold plates, results in utilization of the force oi gravity to fill the molds without the use of forced air or the like, and permits accurately controlling the amount of metal delivered to the mold plates in accordance with that required properly to fill the molds. The lead for delivering the molten metal from the container therefor to the gate means of the mold plates is preferably enclosed to reduce oxidation 01' the metal.

It is also an object to provide an improved master mold plate for not only holding the replaceable molds or mold holders, but also adapted for artificially cooling the molds without loss of heat from the molten metal in its passage through the gate and runner means of the mold plate. It

desired, the mold plate may be utilized to apply heat to the molds to maintain the metal in the molds in molten condition until the desired filiin of the molds is accomplished.

Another object is to provide means for adjusting the casting molds in the master mold plates for the purposes to be hereinafter described, and for locking the molds in adjusted position; also adjusting means for securing perfect fitting of the matched mold plates and the molds carried thereby, and guide means for guiding the plates into perfect fit and for preventing relative sagging oi the plates. 7

Another object is to provide a casting machine of simple and inexpensive construction that may be operated conveniently, and an improved carriage arrangement and movement imparting means for the relatively movable master mold plate.

Further objects and advantages of the invention will appear from the following detailed description, taken in connection with the accompanying drawings, inwhich:

Flgure l is a side elevational view, partially in section, of a casting machine embodying the present invention;

Figure 2 is a vertical section taken on the line 2-2 of Figure 1;

Figure .3 is an end view of the casting machine looking from the left hand end, as viewed in Figure 1;

Figure 4 is a horizontal section taken on the line 4-4 of Figure 2;

Figure 5 is a fragmentary on the line 5-5 of Figure 4;

Figure 6 is a back side view of one of the master mold plates, showingthe means for delivering a cooling medium thereto and. discharging same therefrom;

detail section taken Figure 7 is a fragmentary detail section taken on the line 1-1 of Figure 3;

Figure 8 is an elevational view of the mold insert shown in Figure 5; and

Figure 9 is an elevational view showing a pair of cooperating complementary mold inserts for I producing another form of casting.

The main frame of the particular machine illustrated in the drawings comprises a base section Ill supported upon suitable legs or standards- II. The base section I 0 and standards ll may be formed of cast iron or other suitable material. The two master mold plates for holding the molds are indicated at [2 and I3. One of these plates, 1. e., the master mold plate i3, is relatively stationary. This relatively stationary plate I: is formed integral with an upright supporting member l4, and is supported in upright position thereby as shown. The supporting member or standard I4 is of angular and webbed or other suitable structural form at the bottom, and is bolted at l5 to the base section Ill. The base section III is hollowed out at I6 to receive a removable tray or crucible I'I formed of graphite or other suitable material. This crucible is adapted to catch the overflow and waste metal in the operation of the machine.

A carriage I8 is mounted for sliding movement upon the top of the base section 10. Tongue and groove engagement is provided at I! between this carriage l8 and the base section l0 (Figure 3) for guiding the carriage it toward and away from the mold plate I3. The cooperating portions of the base section and carriage l8 are fully machined, and the carriage may be formed of cast iron or other suitable material. The carriage I! has an aperture adapted to register with longitudinally spaced apertures 2| in the base section III, and a pin 22 is provided for insertion through the aperture 20 and into any of the apertures 2| with which the aperture 20 is registered to lock the movable carriage l8 in any desired position along the base section Ill.

A second carriage 25 is mounted for sliding movement upon the top of the carriage l8. Dovetail engagement is provided at 26 between this second carriage 25 and the carriage l8 (Figure 3) for guiding the upper carriage 25 upon the lower carriage l8 longitudinally toward and away from the mold plate IS. The cooperating portions of the carriages l8 and 25 are fully machined, and the upper carriage 25 may be formed of cast iron or other suitable material.

A handle 21 is provided for manually moving the upper carriage 25 longitudinally along the lower carriage I! on the ways provided by the dovetail engagement at 26. The handle 21 is fixed upon the outer end of a cross shaft 28 which is turned by turning the handle. The shaft 28 is joumaled in the carriage I8, and has a gear 29 fixed thereon to turn with the shaft 2!. The gear 25 meshes with a flat bed gear or toothed rack 30 mounted on the under side of the top carriage 25, so that when the handle 21 is turned the action of the gear 29 on the rack or gear 30 will cause the upper carriage 25 to move toward or away from the mold plate l3.

Instead of manually turning the cross shaft 28, I contemplate the provision of power means for this purpose. I also contemplate automatically controlling the power means for moving the upper carriage 25 automatically to close and open the mold means. Where the machine is operated automatically, the automatic operation will preferably be timed to permit unloading or removal of the castings while the movable master mold plate is parted from the stationary master mold plate. I also contemplate automatically controlling the displacement delivery of the molten metal to the mold means so that this delivery of molten metal will be timed to take place when the mold is closed.

The upright and relatively movable master mold plate I2 is bolted at 32 to a generally elbow shaped arm 33, which arm 33 in turn is bolted at 34 to the top of the upper carriage 25. The movement of the lower carriage l8 provides for bringing the mold plate l2 into and out of the desired relation with respect to the matching mold plate I: and for providing relatively great travel to free the mold plates from relatively long objects. The movement of the upper carriage 25 provides for bringing the movable mold plate l2 into and out of engagement with the relatively stationary mold plate [3.

Adjusting bolts 36, threaded through flanges on the upper carriage 25 and into engagement with the mold plate l2, are adapted for adjusting this plate l2 into parallel relation and accurate registration with the mold plate l3 so that these mold plates and the casting molds carried thereby and the cooperating gates will match or fit perfectly when in closed relation when the plate I2 is in closed position. Further to insure perfect fitting of the matched mold plates, the plate l3 has guide pins 31 secured at 31' thereto, and these pins 31 have sliding engagement in apertured lugs 38 projecting laterally from the opposite sides of the mold plate I2 to guide the plate l2 into perfectly fitting engagement with the plate 13 and to prevent relative sagging between the mold plates.

The matched master mold plates I2 and iii are formed of metal or other suitable material that is preferably a relatively good conductor of heat. Each plate is hollow and shaped generally to a four-sided hollow box-like form. The

cavity 40 (Figure 4) within each plate [2 and I3 is provided primarily for holding and circulating water or other suitable cooling medium within the plate and around the bodies of the molds or mold holders which are in direct contact with the cooling medium, as will presently appear. This cooling hastens congealing or solidification of the hot metal. It is to be understood, however, that the metal will congeal or solidify with natural cooling and that, therefore, the cooling arrangement shown may be omitted within the scope of the broader aspects of the present invention. Moreover, if desired, the cavity 40 of the mold plates may hold a heating medium for applying heat to the molds to maintain the metal in the molds in molten condition until the desired filling of the molds is accomplished.

In the illustrated embodiment of the invention, the mold plates l2 and 13 are provided with a plurality of matched mold holders 42. Six of these mold holders 42 are shown in each of the mold plates l2 and I3, but the particular number of such mold holders in each mold plate may vary .widely within the scope of the present invention. I contemplate one or more molds within the broader aspects of the invention.

Each mold holder 42 is of generally tubular form, provided at its mold carrying end with an integral annular flange or collar 43, and threaded externally at 44. The opposite end of each mold holder 42 is reduced and externally threaded at 45. The mold plates l2 and I3 have registering openings 46 and 41 through which the mold holders are inserted from the front sides of the respective mold plates and into the positions shown in Figure 4. The threads 44 on the mold holders have threaded engagement with the front side of the mold plate at the openings 46, but, the reduced and threaded ends 45 pass freely through the openings 4'I,in the back wall of the mold plate. The mold holders are thus inserted into the mold plates from the front sides of the respective plates, and continue through the cavities 40 and through the .back sides of the mold plates.

The outer surface of the front wall of the mold plate I3 is provided with a recess concentric with each pair of aligned openings 46 aasaocc and 41 for receiving the flanges or collars 43 on the mold holders 4:, and also receiving adjusting nuts 5| threaded upon the threaded portions 44 of the mold holders. Suitable washers 52, beneath the nuts 5|, seat upon the inner ends of the recesses SI and seal the openlugs 46.

The outer surface of the front wall of the mold plate It is faced with a layer 54 of very good heat insulating material such as asbestos mill board, dolomite refractory, or other suitable material which is a Very poor conductor of heat. A suitable material for this Purpose is formed of asbestos and magnesia, the asbestos providing the desired heat insulating characteristic and the magnesia making the material resistant to high temperatures so that the facing will not break down or decompose under such temperatures. The facing 54 may be formed of any material having the desired heat insulating properties to accomplish the results which will presently appear. This facing may be secured to the outer surface of the mold plate I3 by screws (not shown), or in any other suitable or preferred manner.

In the illustrated embodiment of the invention, the mold members 60. are in the form of inserts preferably formed of metal or other good heat conducting material. The outer ends of the particular mold inserts shown are enlarged to seat upon the outer ends of the mold holders 4%. These enlarged outer ends of the mold inserts fit in openings 6| in the heat insulating facing 51. The inner reduced ends 62 of the mold inserts 60 fit telescopically within the mold holders 42, and the mold inserts are readily removable so that they may be replaced or interchanged as desired.

As shown in Figure 5, pins 64, secured to the mold plate I3, project into the recesses III, and are adapted to engage in openings in the nuts 5! to hold these nuts 5| against turning when the mold holder n is inserted into place. Thus, by grasping the opposite end of the mold holder 42 or engaging a suitable tool therewith, the

mold holder may be turned, and this turning movement threads the mold holder axially through the nut 5| to dispose the outer flanged end 43 in position to seat the mold insert 60 with its outer end flush with the'outer surface of the same securely in place. The various mold holders may be adjusted selectively as desired merely by loosening the lock nuts 65 and turning the mold holders to adjust same axially to the desired position, whereupon they may be secured in adjusted position by tightening the nuts 65. Washers 61 are preferably interposed between the lock nuts 55 and the back surface of the mold plate I3 to seal the openings 41.

The two master mold plates l2 and I3 and the various mold holders l2 and mold inserts 60 in each of the master mold plates I2 and I3 are identical, except for the casting cavities 68 which may be alike or different, as desired, so that the foregoing description will sufllce for all. In the illustrated embodiment, the mold holders are inserted before the insulating facing 54 is applied, but this may vary within the scope of the present invention.

Each mold insert has a casting cavity 68 for casting the metal object to the desired shape.

The present machine will handle all kinds of metals or alloys, such as aluminum, bronze, white brass, or any other metals or alloys, and is adapted for producing dense and homogeneous objects of any shape or size. The molds shown in Figures. 4 and 8 have the mold cavities 6| shaped to produce water pump impellers for a well known make of automobile. To provide an opening for receiving the shaft for the impeller the molds 60 shown in Figures 4 and 8 are bored at 69 to support cores III of suitable core material in the casting operation. This may, of course, vary widely within the scope of the present invention. For example, the shaft may be placed directly in the casting machine, with a knurled or otherwise roughened portion disposed in the casting cavity, and the impeller may be cast directly upon the knurled or roughened portion of the shaft. The double carriage arrangement provides adequate movement for introducing and freeing relatively long members upon which castings may be formed.

The matching mold inserts shownat I2 and I3 in Figure 9 have complementary casting cavities II and I5 for producing a metal object of different shape. One of these mold inserts I2 is carried by a mold holder on one of the master mold plates I2, 13, and the other mold insert I3 is carried by the aligned mold holder on the other master mold plate. When the movable mold plate is closed into casting position, the cavities I4 and I5 make up together the complete cavity for casting the desired object.

The mold inserts I2 and I3 are interchangeable with the mold inserts Bil, and mold inserts with other forms of casting cavities may be provided for casting objects of any desired shape or size. By using mold inserts with different casting cavities on the same mold plates at the same time, different objects may be cast in the same casing operation. The mold inserts may be readily removed and replaced or interchanged, and it ispossible to change any one or more objects produced by the machine expeditiously and without changing the master mold plates.

The outer surfaoes of the heat insulating facin'gs 54 of the master mold plates l2 and I3 are provided with vertically disposed matching gates 18 open at the top, as indicated at I9, and closed at the bottom at (Figure 2). These gates open into or communicate with upwardly inclined runners or gates 82 which, in turn, open into or communicate at their opposite ends with the casting cavities in the mold inserts. In Figure 2, communication between the gates or runners 82 and the casting cavities 68 is aiforded through one of the spaces in which the blades of the impeller are formed, the outer ends of the casting spaces for the other blades of the impeller being closed by the surrounding refractory facing 54.

Instead of having a portion of the casting cavity open to the refractory facing 54, the cavity may be confined or enclosed wholly within the metal body of the mold insert, and matching openings may be provided as shown at 84 (Figure 9) for delivering the molten metal into the casting cavities from the gates or runners 82. In any event, the adjustable mounting of the mold holders 42 not only affords the adjustment already described, but provides for adjusting the molten metal receiving openings of the mold inserts into proper registration with the gates or runners 82.

Where the mold is cooled, water or other cooling medium is supplied into the cavities 40 in the master mold plates I2 and I by a cooling medium supply line 00 having, for example, flexible connection at 00 with the cavity 40 in the master mold plate I 0 and flexible connection at 90 with the cavity 00 in the master mold plate I2. The cavity 00 of each plate I2 and I0 is provided in proximity to the top thereof with air vent openings 03. Upright overflow pipes 04 within the cavities 00 of the respective plates I2 and I0 discharge through overflow or discharge lines 05.

In making up the mold inserts, these inserts are preferably machined from the centers of the cavities in the mold holders to flt the cavities of the mold holders. As already pointed out, the mold inserts are fitted into the cavities of the mold holders for use and are readily replaced by other mold inserts, as desired. These inserts enable any desired mold to be removed from any multiple or single set plate without disturbing the balance of the molds or the machine setting. Moreover, the locking and adjusting of the molds or mold holders are accomplished independently and without disturbing the machine setting in any way. The use of mold inserts with mold holders enables absolute accuracy and low mold cost. The features of adjusting and holding the molds and inserts and of adjusting the.movable master mold plate are important aspects of this invention.

Instead of employing mold inserts in combination with the mold holders 02, the mold holders may have the casting cavities formed directly therein, within the scope of the present invention. This would eliminate the necessity of separate mold inserts, and in such case the mold holders 42 would be removed from any multiple or single set plate and replaced with other mold holders having different casting cavities to form different objects.

The right hand end of the machine as viewed in Figure I is provided with a metal heating furnace 00. This furnace 00 has a suitable burner 99 positioned below the container I00 for the molten metal- The burner 00, which may be an oil or gas burner or any other suitable burner, is supplied with fuel through a fuel supply line I02, and, for example, in the case of a gas burner, air may be admitted at I00. The fuel supply line I02 is provided with a control valve indicated at I00. The furnace 00 is supported in elevated position upon the base section I0 by uprights I05.

With the illustrated construction, the molten metal container I00 is positioned in close proximity to the mold means. The furnace 90 is covered as indicated at I00, and a suitable refractory lining may be provided as indicated at I00. The molten metal container I00 has a spout indicated at IIO, which opens into a refractory lead or trough II2. This lead or trough II2 slopes downwardly through the refractory lining I00 and covering of the furnace, and its opposite end is positioned to discharge the molten metal into the open upper ends of the gates when the mold is closed. The molten metal container I00 may be supported within the furnace in any suitable or preferred manner, as by means of diametrically opposite bosses or trunnions I II which engage in slots IIS in the furnace.

For the purpose of delivering the molten metal to the mold. I provide a displacement plunger IIO (Figure 1) which is adapted to be lowered into the molten metal container I00 to displace the molten metal therefrom and to be raised out '01 the container I00. The plunger 0 is pivoted at II! to a link IIO, which link is in turn pivoted at IIO to an operating lever I20. The lever I20 is pivoted at I2I to an arm or bracket I22 flxed. for example, to the furnace 00. The lever I20 is maintained in the position shown, with the displacement plunger Il0 elevated by means of a spring I20 coiled, .for example, about an arcuate guide I20 pivoted at I20 to the lever I20.

The particular lever arrangement shown provides one suitable means for manually operating the plunger 0. This means may vary widely within the scope of this invention, and, as already pointed out, the plunger may be operated automatically and in timed relation to the closing of the mold. When the mold is closed and the plunger IIO depressed into the container I00, the level of the liquid metalrises in the container until it reaches the level of the spout Ill. The liquid metal will then flow out of the container through the trough or lead H2 and into the matching gates 10 of the mold. Upon entering the mold plate, it is distributed direct to the one or more mold inserts or mold members through the openings provided in the insulating facings of the master mold plates. -When the mold receives all the metal necessary entirely to flll all of the impressions or casting cavities, the metal will rise and stand in the refractory lead, at which time the operator will make the necessary motion mechanically to cause the plunger IIO to rise up out of the container I00.

The speed at which the plunger is operated regulates the flow of metal from the container, and, as already pointed out, this displacement method in conjim'ction with the arrangement of the mold plates results in utilization of the force of gravity in filling the molds and permits accu rately controlling the amount of metal delivered to the mold plates in accordance with that required properly to fill the molds. The displace ment method minimizes the time and heat loss of getting the metal from the container to the mold plate, and oxidation of the metal caused by exposure to the atmosphere is rediiced.

By its position in the opening I at the top of the furnace 00, the plunger 0 is subjected to the hot gases or heat of the furnace, so that it will not chill the molten metal in the container I00 when lowered, into the same. The plunger I I0 is preferably made of carborundum or of a combination of insulating and refractory. material of the character employed, as the facings 50, cast into shape, or of other suitable material, so that the plunger will not. be disintegrated or otherwise deleteriously affected by the hot metal, particularly by molten aluminum or any of its bronze alloys. 7

With the plunger displacement method of delivering the molten metal to the mold means of the machine, the plunger does not require a close fit in the molten metal container I 00. If the plunger wears down, its operation may be adjusted at III to secure proper displacement of the molten metal from the container I00 when the plunger-is lowered into the same. Moreover, with the utilization of the force of gravity indelivering the molten metal into the mold means, the danger of flashing of molten metal, particu larly if the molds do not close tightly, is eliminated. When the molten metal is delivered to the mold means under high pressures, as commonly done heretofore in the art, this danger of flashing of hot metal from the mold has presented a diiiicult problem.

As the molten metal passes through the openings in the refractory iacings 54 or the master mold plate, heat loss from the molten metal is reduced or substantially eliminated by reason of the heat insulating character of these faclngs. This prevents chilling or solidification or the molten metal in the gate or runner means or elsewhere in its passage to the mold, and assures that the molten metal is delivered into the mold in the desired molten condition completely to fill the mold and produce good homogeneous and dense castings at all times. Moreover, the maintenance of the metal in molten condition in its passage through the gate and runner means eliminates cleaning of gates and runners irom the finished work and clogging of the metal in its passage to the mold means. The arrangement of the master mold plates permits the molten metal to drain iromthe runners and gates in the heat insulating iacings lwhen the mold plates are parted by moving the mold plate l2 away from the mold plate l3, and this molten metalwhich drains from the runners and gates in the insulating facings flows into the removable tray or crucible ll.

Where a cooling medium isheld and circulated directly within'the master mold plates I2 and I3, it will be noted that the mold holders 4!, which are of good conducting material, are in direct contact therewith, and this, together with the good conductivity of the mold inserts 60, extracts the heat from the molten metal in the casting cavities to. This cooling hastens the congeal in or solidification of the hot metal in the casting cavities. At the same time, the insulating facings 54 prevent any cooling action upon the molten metal passing through the openings in these iacings 54, with the advantages already set forth.

The large cooling bodies provided in the master mold plates of my present invention provide for rapidly and effectively dissipating the heat from the mold holders and mold inserts. This protects these parts against cracking or other injury under excessive temperatures during the operation of the machine.

It is to be understood that the metal will congeal or solidify in the mold cavities with natural cooling, and that the'hollow formation and cooling medium may be omitted within the scope of the present invention. It is to be further understood that heat may be applied to the casting molds to maintain the metal in the desired molten condition until the casting cavities are completely filled. The top of the gate 18 in the facing 54 of the mold plate I! may be provided with an upwardly extending funnel-like portion I40, ii desired. The top of the furnace is shown as provided with a cover I42 having an opening 3 through which the plunger H6 operates. The facing plates 5t are preferably provided with notches, as indicated at I45 inFigure 2, to permit the escapeof air or gas from the casting cavities so that there will not be any trapping of such air or gas in these cavities such as might impair the homogeneity of the castings.

In the operation of the machine, the moldis closed by moving the movable master mold plate l2 into closed and accurate matching engagement with the relatively stationary mold plate 13. The mold holders andmold inserts, as well as the gates and runners in the respective master mold plates, match accurately, and when the mold is closed the plunger H6 is operated to discharge the molten metal into the mold by displacement. As soon as the mold cavities are filled and the metal in these cavities is set, the mold plate II is parted from the mold plate II, and the overflow and waste metal in the openings in the face plates 54 drains into the crucible II. Where the operation of the machine is automatic, it is timed to permit removal of the cast objects while the mold plate I! is parted from the plate ll. The cycle of operation is repeated as often as desired.

I do not intend to be limited to the precise details shown or described.

, I claim:

1. In combination, a master mold plate, a mold holder having screw threaded connection with said plate, a mold removably mounted in said mold holder, a heat insulating racing mounted on said mold plate and having an opening to receive said mold and gate means communicating with said opening for delivering molten metal to said mold, means for rotating said mold holder to adjust the position of said mold relative to the surface of said heat insulating facing, and means connected with the end of said mold holder opposite said mold {or locking said mold holder in adjusted position. v

2. In combination, a frame, a relatively sta-- tionary master mold plate on said frame, carriage means mounted for movement toward and away from said relatively stationary master mold plate, a relatively movable master mold plate mounted on said carriage means for movement to closed position relative to said first mold plate and adapted to be parted therefrom, readily removable casting molds on said mold plates, and. heat insulating facings formed of a material of low heat-conducting capacity mounted on said" mold plates and having cooperating gate means formed in said heat insulating facings for delivering molten metal to said molds.

3. In combination, a frame, a relatively stationary master mold plate on said frame, carriage means mounted for movement toward and away from said relatively stationary mold plate, a relatively movable master mold plate mounted on said carriage means for movement to closed position relative to said first mold plate and adapted to be parted therefrom, readily removable casting molds on said plates, heat insulating Iacings formed of a material of low heat-conducting capacitymounted on said mold plates and having cooperating gate means formed in said heat in- 5 sulating facings for delivering molten metal to saidmolds, and means for adjusting one of said mold plates to provide matching relation of said plates and the casting molds and gate means thereon.

4. In combination, a frame, a relatively stationary master mold plate on said frame, a carriage mounted for movement on said frame toward and away from said relatively stationary mold plate, a second carriage mounted for movement on said first carriage toward and away from said relatively stationary mold plate, a relatively movable master mold mounted on said second carriage for movement to closed position relative said first mold plate and adapted to be parted therefrom, casting molds on said mold plates, heat insulating facings formed of a material of low heat-conducting capacity mounted on said mold plates and having cooperating gate means for delivering molten metal to said molds, means for adjusting said casting molds in said plates and for securing same in adjusted position, and means for adjusting one of said mold plates to provide matching relation of said plates and the casting' molds and gate means thereon.

5. In combination, a mold plate having a cavity therein, said plate having aligned openings in the walls at opposite sides of said cavity, a tubular mold holder fitting through said openings, a threaded member held to said plate and having threaded engagement with said mold holder to produce axial movement of said mold holder by turning thereof, a nut having threaded engagement with said mold holder and cooperating with said plate to lock said mold holder in adjusted position, and a mold insert removably fitted in said holder.

6. In combination, a pair of relatively movable molds forming a mold cavity. cooling means therefor, complementary parts formed of heat insulating material carried by said molds and forming gate means communicating with said mold cavity, said parts being substantially non-conductive as regards the transmission or heat so that molten material in the gate means remains in molten condition after the metal in the cooled mold cavity becomes solid, means for parting said molds, and means for receiving the molten material flowing from said gate means when the molds are parted, said receiving means retaining the molten material from the gate means in a pool in which only the surface is exposed.

7. In a molding machine, a hollow mold plate having opposite walls, there being aligned apertures in said wall and one of said walls having an enlarged recess about the aperture therein, a tubular mold holder disposed in said aligned apertures and having a flange at one end disposed in said recess, means adjustably fixing the position of said mold holder in said aligned apertures, and a mold insert removably disposed in the tubular mold holder and having a head disposed against said flange.

8. In a molding machine, a hollow mold plate having opposite walls provided with aligned apertures, one of said walls having an enlarged recess about the aperture therein, a tubular mold holder extending through said aligned apertures and having a head disposed in said recess and a threaded connection with said recessed mold plate wall, the flange end of said tubular mold holder having an enlarged interior bore and the opposite end having a smaller tool receiving bore, a mold insert having a shouldered head and a shank portion adapted to be disposed in said enlarged bore with the shouldered head disposed against the flange of said mold holder, a heat insulating facing secured to said one wall of the mold plate and having an aperture adapted to receive the head end of said mold insert, rotation of said mold holder serving to position the head of said mold insert substantially flush with the outer surface of said heat insulating facing, and means at said other end of the mold holder for locking the latter in adjusted position in the mold plate.

DONALD H. GARTH.