US698596A

US698596A - Casting-machine.

Info

Publication number: US698596A
Application number: US243500A
Authority: US
Inventors: Curtis H Veeder
Original assignee: Individual
Current assignee: Individual
Priority date: 1900-01-23
Filing date: 1900-01-23
Publication date: 1902-04-29
Anticipated expiration: 1919-04-29

Description

\ N0'. 698,596.` Patented Anr. 29, |902.

c. H. valama.` CASTING MCHlNE.

(Application led Jax-1. 23, 1900.)

(No Model.) -8 Sheets--Sheet I.

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No. 698,596. Patented Apr. 29, |902.

c. H. vEEDER. CASTING MACHINE.

(Application filed Jan. 23,: 1900.)

(No Model.) 8 Sheets-Sheet 2.

wenfol," e Keer No. 698,596. l Patented Apr.'29, |902.

C. H. VEEDEB.

CASTING MACHINE:

(Application led Jan. 23, 1900.;

(Nn Model.) 8 Sheets-Sheet 3.

Fig 3.

No. 698,596. Patented Apr. 29, |902.

C. H. VEEDER. CASTING MACHINE.

(Application filed Jan. 23, 1900.)

8 Shasta-Sheet 4.

(N0 Mdel.)

n, m. ,WW 17m fw No. 699,596. Y Paf-mma Apri. 29, |902.

9 c. H. vienen. CASTING MACHINE.

A (Applimionjmd 'm1, 2s. 1900.) 'ma Model.) s sheets-sheet 5.

Mullin.:

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8 Sheets- Sheet l6.

No. 698,596. Patented' Apr. 29

` i c. H. vEEnEn'.

CASTING MACHINE.

` (Application led Jgn. 28. 1900.) (No Model.) l

me Nonms PETERS co. FjHoToLn'no., wlxsnmm'ou. ma.4

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- IPatented Apll. 29

C. H. VEEDER.

CASTING MACHINE.

(Appliation led Jin. 28, 1900.) v

s sheets-Sheer 7.

(No Model.)

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No. 698,596. Patented Apr. 29,1902.

C. H. VEEDER.

yOJSTING MACHINE.

(Application filed Jan. 23. 1900.)

8 Sheets-Sheet 3.

(No Model.)

ws noms meas no.. mornin-nox, wksnmumu, n. c.

UNITED STATES VPATENT OFFICE.

CURTIS II. VEEDER, OF HARTFORD, CONNECTICUT.

j C-AsTINe-MACHIN E.

SPECIFICATION forming* 0f Letters `PtteIrt N0. 698,596, dated. April 29, 1902. Application filed January 23, 1900. Serial No. 2,435. (No model.)

erations of planing, turning, the., butcan beused and assembled with other` parts with the bearing-surfacesin thefcondition in which they come from the molds and under conditions Where exceptionally Well-finished bearing-surfaces are required in order to permit the proper movement of parts upon one an-` other. This result I attain by employing a casting-machine so constructed and capable of operating in such a manner as to condense the molten metal most perfectly during` the making of the casting and before `the` completion thereof. I have found that the best results can be secured by producing a vacu um in the mold intowhich the metal is to be poured and then forcing molten metal under pressure into the exhausted mold until the mold is completely filled. When castings are formed in this way, all of the spaces and corners of the mold, no matter how small they may be, are completely filled by the molten metal forced thereinto and the cast ing corresponds Vexactly `in contour to the mold, every minute projection or indentation in which is reproduced perfectly as an indentation or projection in the finished casting, no matter how complex the pattern to be reproduced may be. Moreover, in every case castings formed in this manner are of a dense, homogeneous, and exceedingly fine crystalline structure throughout.

The present invention is in the nature of an improvement upon that shown, described, and claimed in my application, Serial No. 738,269, filed November 27, 1899, to Which reference may be made. The present invention embodies many important features of novelty not shown in said application, and the machine in which. these features are ein# bodied will preferably operate entirely autoat a high rate of speed Without requiring any special care from an attendant.

The molten metal may be delivered to the mold in many Ways; but I prefer to inject it into the same under high pressure, so that the stream Will be forced violently into every portion of the mold. In the present case I have employed for this purpose moldilling means operating as a hydraulic ram in which a plunger of relatively large diameter exerts at the proper time a violent pressure upon a column of molten metal and sets the same in motion before it is injected into the mold. Thus the movement of the plunger is converted into kinetic energyoroz's uioctof the molten metal before the latter is permitted to enter the mold, and hence when this molten metal is injected into the mold at the proper time it Will be moving under the influence not only of the pressure applied by the plunger, but also of its own kinetic energy, and the stream of meta-l forced vinto the mold will therefore be injected into the mold While traveling at a higher rateof speed than it Would have if it were forced out by a plun ger when not under the inlluence of its own lkinetic energy, as is the casein the operation described in my application hereinbefore mentioned. An additional advantage resulting from the use of a hydraulic ram for injecting the molten stream is that as the metal is in constant motion just before the casting operation it will have no opportunity to cool in the vicinity of the outlet-opening leading to the mold, and the molten bath at that point will at such time be in a condition of most perfect fluidity, owing to the constant circulation of the fluid and the consequent matcally in order that it may make castings commingling of the hottest portions of the bath with the molten metal adjacent to the Walls of the containing vessel and other points Where it is most likely to become cool, and therefore less fluid.

One of the most important features of the present invention as distinguished from that described in my aforesaid application is the provision of means forchecking crystal1ization of thecasting and chilling the same before it has cooled'off and has been removed from the mold. The object of this is to produce a casting in which the metal Will be of IOO 'a more dense and homogeneous structure and will exhibit when broken a finer fracture than castings made in substantially the same way, but not chilled. As is well known, many metalscrystallize most perfectly-that is,they tend to form crystals of maximum sizewhen permitted to cool slowly, the tendency to crystallize in this manner being more marked with some metals, of course, than with others, antimony being one which tends to form relatively large crystals unless the process of crystallization is checked and the tendency of the metal in cooling to form large crystals is overcome. It has been found in practice that while castings formed in vacuo and under pressure are close-grained and nely crystalline, yet when the casting so made is rapidly cooled and chilled before solidiication the resultant product has a very much ner grain, the crystals are much more finely divided, and hence the casting is much more perfect in every way and will produce better results. The improvement in the product resulting from this sudden cooling or chilling of the molten metal is not coni-ined to any particular metal, although it is of course much more marked with some metals or al- -1 loys than with others, and the action of the tion, such an alloy being one that will be used frequently in forming castings in a machine of this type.

' In the drawings accompanying and forming part of this application, Figure lis a side elevation of an automatic casting-machine embodying my present invention. Fig. 2 is an enlarged plan of the same with portions of the framework and other parts broken away. Fig. 3 is a sectional elevation of the same, the section being taken in line 3 3, Fig. 2, looking in the direction of the arrow. Fig. et is a side elevation of the same and shows the parts in the same positions as in Fig. 1. Fig. 5 is a substantially central longitudinal section of the same with the parts in the positions shown in Fig. Ll--that is, the positions which they assume at the end of the casting operation. Figs. 6 and '7 are views similar to Fig. 5 of a portion of the mechanism and illustrate the parts in successive positionsat other stages of the operation. Fig. S is an enlarged vertical section of one of the airpumps. Fig. 9 is a sectional detail of the upper portion of the same, the section being taken in a diiferent plane. Fig. 10 is a sectional elevation of the upper portion of the other air-pump. Fig. 11 is a vertical section of the same, the section being taken in a different plane. Figs. 12 and 13 are enlarged sectional elevations, viewed in the same direction, of the two main portions of the mold. Fig. 14 is a transverse section of that portion of the mold shown'in Fig. 12. inclusive, are transverse sectionsillustrating the successive steps in the operation of stripping the casting from the separable mold;

Figs. 15 to 18,A

and Fig. 19 :is an enlarged perspective view of a casting which may be made by my improved machine.

Similar characters designate like parts iu all the gures of the drawings.

In my application hereinbefore referred to I illustrated a simple type of mechanism for forming castings; but in the present case I have shown a complete automatic machine, by means of which castings may be formed and ejected from the machine regularly and at a high rate of speed without requiring any considerable amount of attention from an operator.

The several operative parts of my improved machine may be mounted on a suitable framework or bed, such as A, supported on legs in the usual manner and having a main shaft 2,

,which may be driven by a band-Wheel 3 from any suitable source of power, and from this shaft the movements of all of the automatically-operatiug parts of the machine may be derived.

Any suitable means may be employed for melting and holding the metal from which castings are to be formed; but in the present 'case I have shown at one end of the framework A two melting-pots, one of which is designated in a general Way by M and may be employed to melt the stock and may also form a reservoir, from which the metal may be drawn off from time to time into another or main vessel, such as the melting-pot M', for use. The contents of these two pots maybe kept hot in any suitable manner, ordinarily by gas-jets. From time to time the meltingpot M may be replenished from the meltingtank M, as through a channel 4, controlled by a valve 5.

In the construction shown herein the melting-pot M' has a well 6, from which a passage 7 leads to a chamber 8, having two or more openings leading therefrom. One of these openings is indicated herein by 8 and isintended to receive molten metal from the tank M at a point considerably below the surface of the metal and keep the chamber 8, the passage 7, and the well o' filled with the molten metal. rIhe other opening, which is designated by 10, serves as an outlet,1.hr0ugh which the metal may be delivered to the mold at each operation. The chamber 8 in the present case is formed partly within and partly without the melting-pot M', a nozzle, such as 12, being secured to said melting-pot in the construction shown and being so shaped internally as to contain a portion of the valvechamber 8 and also the discharge-opening 10.

For the purpose of controlling the flow of molten metal into the mold I prefer to mount within the valve-chamber 8 and the openings 8' and 10 a valve so constructed as to close the opening 10 when a casting is not being made. This valve may also serve to open communication through the passage S with the main body of metal in the melting-tank and when so constructed as to accomplish IOO IIO

both of these results constitutes a doubleaction valve. y y u For the purpose of supplying a charge of metal to the mold I prefer to' make use of moldfilling means embodying a member which will act upon the'metal in such a manner as to force the molten charge under high pressure into the mold, and thus assure the filling of all corners thereof. Ordinarily a plunger, such as p, will work in the Well 6 and when depressed will cause the metal to be injected in a small column or stream into the mold.

Y The plunger p may be carried at the lower end of a plunger-rod 26, which may be supported for vertical reciprocation in a support or cross-piece 27, bolted in this case to the upper side of the melting-pot M', said plunger-rod being operated in this case by one end 28' of a lever mounted on a rock-shaft 28,

which `may be jonrnaled in suitable bearings on said melting-pot, the other end- 28" of said lever being secured to a connecting-rod 29, the operation of which is controlled by the main shaft 2. In the construction shown the lower end of the connecting-rod 29 is pivoted tothe forked end o'f one arm of an angle-le- "ver 30, pivoted on a short pin or shaft 3l at one end of the framework, the other arm 30' of the angle-lever having secured thereto a coiled spring 32, connected at its otherend to a xed point. In this case a rectangular block 30" is supported in the bifurcated arm of the angle-lever 30, and it mayY have a quick-let-off face, as shown in Fig. 4, to coact with a corresponding quick-let-off face of a cam 33 on the shaft2 in order to permit the plunger p to be forced down rapidly by the action of the spring 32 when the block 30" drops off from the face of the cam 33.

The valve o is intended to reciprocate in` the chamber S and in the openings 8 and 10 l and during a portion of` a complete cycle of operations will be controlledin its movements by the molten metal in the various passages `and in the main portion of the melt` ing-pot lvl' and will move back and forth freely in accordance with theiow of the metal in the one direction or the other; butduring another portion of the cycle of operations it is intended in this case that the valve shall` be controlled positivelyto close the passage l0, open the passage S', `and maintain `the passage 8' openduring the early stages of thel The valve is practically unbalanced, the area of the pas-` sage 8' being greater than that of the pas-- next descent of the plunger p.

sage 10 and the inertia of the valve, the hydrostatic pressure of the molten metal, and

the suction at the opposite side of the mold- Space being sufficient to hold the valve closed to close the passage 8', and consequentlyopen the passage A 10, so A that the molten metal whilemoving at a high rate of speedwillbe diverted from one passage into `the other.

The construction and operation of these parts will be added to the force exerted by the mere thrust of the plunger p and will therefore increase the velocity with which the molten metal will be forced through the outlet l0 in` the nozzle 12 and thence into the mold. The

action just described does not take place in operating the mechanism shown in my application hereinbefore referred to, for the reason that in that case the parts are so organized as to cause the closure of the passage S'before the molten metal in the well 6, the passage 7, andthe chamber 8 is set in motion.

4Hence in the present case the streamof molten metal is not only injected forcibly into the mold, but is forced out through theopening l0 While under the influence of its own kinetic energy or fv/L's rfi/Ua, andtherefore the mold-filling means herein shown constitute and operates as a hydraulic ram.

'For the purpose of holding the valve o during the early stages ofthe descent of the pistonp in the position shown, for example,`in Fig. `5, with the passage 8" OpemImaymake use of any suitable valve-controlling or valveoperating mechanism; but here Ihave illustrated at 35 a rock-arm carried by a rockshaft 35, mounted in suitable bearings and also controlled iny its movements by the main shaft 2. be any suitable for the purpose,ibut` in this case are substantially similar to those previously described-for operating the plunger. A

rock-arm 35", secured to the rock-shaft, isA pivoted-in this instance at its free end tothe upper end of a connecting-rodBG, the `lower in suitable bearings on the framework and somewhat similar to the angle-lever 30. i This rock-frame may be constructedin any proper manner, but in this case embodies a pair of angle-arms 37l` and 37", the former of which IOO The connections to this shaft may IIO `end of which is pivoted in turn to arock- `frame 37, pivoted on a short shaft 38, carried hassecured thereto a lever formed from a pair of strips 39, properly spaced, and between which an antifriction-roll `4() is supportedto c operate with a cam il on the shaft 2, said Y cam havingasmall wi er 4l' rejecting thereb l b from forshifting the rock-arm 35' away from the valve fu momentarily when a casting is to be made; i A spring 42, connected to the arm `37" and to a `fixed point, serves to hold the antifriction-roll 40 in the path of the wiper Lilon the cam 4l and to operate the rock-arm 35quickly to close the valve o and cut olfthe supply of the metal to the mold. lIn order to enable the operator to Withdraw the roll 40 from the path of the Wiper 41', I have shown at 43 a lever or arm to which the strips 39 are pivoted, said lever having a long heel 43', the short end of which will rest on the rock-frame 37 when the roll 40 is in its operative position, and the long side` of which will rest on said rock-frame when the lever 43 is turned to shift the roll 40 out of action.

An important feature of my present invention is the employment, in connection with mold-filling means and with a mold of suit- "able construction, of mechanism which will operate to advance one of these toward and retract it from the other alternately, usually at regular intervals, and in the construction shown I employ a separable mold `having a plurality of mold-sections, one or more of which may be shifted relatively to another or others and also relatively to the dischargenozzle of the mold-filling means. Vhen such a separable mold is employed, it may have not only a movement toward and from the moldfilling means to withdraw the sprue of the casting from the latter, but the mold-sections may be alsov shifted relatively to each other or to one another in such a manner as to strip the casting from the mold, it being understood that no matter how many mold-sections there may be the movements thereof should be controlled by the mechanism automatically and that the mold-sections should have such relative movements as to separate properly without impairing the casting while it is being stripped therefrom.

Many different styles ofy molds may be employed in connection with my improved machine for forming castings of various shapes so long as themolds diifer only in the shapes of the mold-spaces; but in the present case I have illustrated a mold embodying three moldsections capable of movement relative to 'one another to permit the stripping of the completed casting therefrom. The mold shown is designated in a general way by O and has three mold-sections, which are indicated, respectively, by o, o, and o". (See Figs. l2 to 18, inclusive.) Here the mold-section o has the usual ingate or sprue-hole 17, adapted to communicate with the opening l0 in the nozzle 12. Said mold-sections may also coperate with a pair of nipples, such as 18 and 19, the latter of which in this case practically forms part of the mold and coacts with the mold-section o and with the opening 10 in the nozzle 12 to form the sprue-hole. The

parts

18 and 19 may be readily replaced at any tim e, as will be evident, and are so connected as to permit the section o to be moved without be# ing shifted themselves.

All of the sections of the mold may be supported by mold-carriers, each mold-section in this case having a separate carrier on which it is supported and by means of which its movements are controlled. Preferably each mold-carrier will be supported by another and in such a manner that each carrier and its mold-section may be positively located and guided during the movements thereof, one mold-section being supported in this case on a main mold-carrier, while the other two moldsections are carried,respectively, by auxiliary mold-carriers both supported on the main mold-carrier and movable relatively thereto and to each other. Here the mold-section 0/ is fastened directly to the main mold carrier or carriage, which may be substantially a skeleton frame, such as that designated herein by H, this skeleton frame being supported in this instance for movement toward and from the discharge-opening 10 and also having a slight vertical movement, owing to the fact that in the construction illustrated it is actuated by means of and forms one element of a parallel movement. At the end thereof adjacent to the mold this frame H is supported by a two-part swiveled yoke pivoted on the framework at 51, said yoke being des ignated by 50. At the-end thereof remote from the mold the skeleton frame may be supported by a rock-framev also pivoted on the framework, as at 53, the upright portion of the rock-frame being preferably parallel with the yoke 50. Here this rock-frame consists of a pair of rock-arms 54, parallel with each other and pivoted at their upper ends to the rear end of the skeleton frame H. An antifriction-roll 55 is mounted between these arms 54 and cooperates with a cam 56 on the shaft 2, which cam controls the movements of said frame and of the mold. In the present construction I have also shown an angle-arm 57 in xed relation With the parallel frame-supporting arms 54, and from this angle-arm 57 a link 58 leads to a strong helical spring 59, the lower end of which is connected to a cross-bar 60 of a rock-frame, (designated in a general way by R,) which serves to operate the moldexhausting means, (hereinafter to be described,) the rock-shaft of this rock-frame being designated by 6l and being supported between two of the legs of the machine. rlhis spring of course tends to force the skeleton frame and the mold-section carried by it toward the discharge-opening 10, and if the other mold-sections are also supported on the skeleton frame they may also be controlled to a considerable extent by said spring.

In the present construction the mold-section o is supported on a mold-carrier positively guided by guide members or openings on or in the skeleton frame. This auxiliary moldcarrier is in this instance a sliding frame having a pair of parallel slide-rods 62, sliding in parallel guideways in cross-pieces, such as 63 and 64, secured to and forming part of the skeletonlframe I-l. This sliding frame is designated in a general Way by h, and the slide-rods 62 thereof are connected at their forward ends to a cross-head 65, in which the mold-section ois mounted. The auxiliary carrier 7?, may derive its movements partly from the main carrier H and partly IOO IIO

from a pair of springs 66, coiled aroundthe slide-rods 62 and working between a pair of stops 67,1ixed to said slide-rods, and the crosspiece 64C of the frame H. These springs will normally tendto separate the nipple 18 and the nozzle 12 and will normally hold the rear ends of the slide-rods62 in contact with astopface or stop-faces, such as 68, on the framework, these stop-faces being of such height as to provide for the slight vertical movement of the slide-rods. The third mold-section o isalso preferably mounted on an auxiliary mold-carrier carried on and guided'by the main frame H. In the construction shown thisl second auxiliary mold-carrier, which is designated by 7i', consists, essentially, of 'a cylindrical bar70,supported for reciprocation in corresponding rounded' openings in. the members 7l and 72 of the. skeleton frame, a link-frame, such as 73, being pivoted to the rear end of the bar h and also pivoted` to one arm 74 of an angle-lever pivotcd on the frame II at 75and also connected by means of a spring 76 with a fixed -point on said frame. The other arm 74.' of said angle-lever carries in this case an antifriction-roll77, adapted to coperate with a fixed actuator or cam 78 on the `main frame ofthe machine. Itwill be evident now` that the bar h', carrying the mold-section o,will be advanced by the spring 76 to its closed position and-will be retracted by the angle-lever when the latter is operated by the cam 78'on the withdrawal of the main frameH from the mold-filling-means.

Of course the mold-section o" may beformed in many dierent Ways; but here I have illustrated a mold-section having a longitudinallybored hub 20,With a pin 20' driven therein at one end, while the other end of the bore is threaded to receive the end of a long screwbolt 2l,by means of which the member 20 may be firmly wedged in place in the bore h.

It will be noticed that all of the several mold-carriers are actuated toward and from the mold-filling means (in this casein a single path) and that their movements are only varied as to the extent of their travel in such path and as to the time during which suchl movements takeplace.

One of the most important features shown and described in my aforesaid application is the employment of means forexhausting air from the mold prior to the casting operation, and this feature is retained in the present mechanism, but in a very much improved form. I have found that the best results cannot be obtained by exhausting the mold `at a single operation, as the resultant vacuum is not high enough, and the quantity of air left in the mold while not great is still sufficient to interfere with the casting operation and prevent the obtainment of the finest prod uct. In the present case I have shown in connection with the mold mechanism a plurality of separately-effective. mold-exhausting means, and in the preferred construction a` `pair of successively-effective mold-exhaust- V t l ing devices or air-pumps will be employed to exhaust the air from a single mold, as I have found in practice that after one pump has operated and has almost completely exhausted the mold if another is brought` into action and its piston is moved a considerable distance before communication is made with the injected into the molduntil the latter has been completely exhausted, and it should be injected before the vacuum so produced can be impaired. i

The differentially-operative mold-exhausting means which l will ordinarily make use of will be a pair of pumps, such asP and P', the former of which is the partial-exhaustion pump and the latter the complete-exhaustion pump. In most respects they may be of any well-known construction, but will be effective at diiferent times, and one of themin this case the pump P'-may serve as a means for supplying air to the interior of the mold after a casting has been made, in order that the outside atmospheric pressure on the moldsectiens may be relieved and the latter separated readily. Of course the air should be admitted to the mold only after the complete formation of the casting, and hence the mold will be alternately exhausted and supplied with air. For the purpose of supplying air to the mold after the casting has been completed one of the air-pumps may not only have a valve for opening communication between the pump-cylinder andthe mold, but ,also an additional or auxiliary valve in the `nature of a relief-valve for establishing communication between the outer air and the mold at the proper time. Here the pistonrods 8O and 80' of the two pumps,'each passing through an appropriate stuing-box 80", are adj ustably connected with the rock-frame R and are operated by crank-arms 8l and 8l',

Iconnected to a pair of

cranks

82 and 82 on the `main shaft 2, and hence the pistons of the air- :pumps are operated directly from such shaft, `the spring 59 assisting during the ascent' of the pistons. Each pump will have a piston, as S3, with a valve, as S-i, therein and an exhaust-valve, as` 85, in the cylinder, and each ofthe two pumps inthis case will also have a cover, such as 89 or 89', supporting a valve controlling communication between the pump-cylinder and the mold, but these valves shouldnot operate in unison, but instead the valve 86 of the pumpP is intended IIO casting operation.

Ato the mold, and the pump P' may also have an additional valve or ad mission-valve,\vhich will control communication between the outer air and the pump-cylinder. This auxiliary valve or admission-valve may be a puppetvalve, such as 88,. seated in a bore in the main puppet-valve 86' and controlling communication between the port 87" and the outer air, all of these

valves

86, 86', and 88 being operated in proper timing,preferably from the main shaft. 2, through suitable connections, such as those shown herein. The valve 86 is held to its seat by a spring 90 and is raised therefrom by one end of a lever 91, the other end of which is pivoted to a connecting rod or link 92, the lower end of which in turn is connected to one arm of an angle-lever 93, pivoted on the framework of the machine, the other arm of the angle-lever carrying an antifriction-roll 94, coacting with a cam 95lon the main shaft 2. The connections from the valve-operating lever for the valve 86' to the shaft 2 being substantially the same as those just described need not be particularly described, but are indicated herein by corresponding figures and prime-marks. It should be noted, however, that the cam 95' for operating the valve 8G' is not located in the same position on the shaft 2 as the cam 95, but instead is so placed as to raise the valve 86' after the valve 86 has been liftedand closed again, in order that the mold may be irst partially and then completely exhausted.

Referring now particularly to Figs. l0 and 11, I have illustrated the meanswhich I prefer to employ for operating the auxiliary p'uppet-valve 88 for establishing communication between the outerairand the mold. Here the bifurcated end of the valve-operating lever 91 carries a pivoted liftingpawl 96, the working face of which is adapted to engage a co- Ywhile when the Valve 86' descends to its seat the pawl 96 will lift the relief-Valve 88 from its seat and open communication between the outer Yair and the port 87'. This action of course should not take place until after the Proper outlets are provided, as at 97 and 97', for the escape of the air from the pump-cylinder.

For the purpose of assuring the obtainment of a very high vacuum in each of the cylinders I have illustrated at 98 and 98" a pair of pipes which will lead to an oillreservoir, (not shown,) from which reservoir oil will be drawn by the pistons, and this oil will serve not only to lubricate said pistons, but also to form airseals between the pistons and the walls of thecylinders and between the outlet-valves (one of which is shown at 85) and their seats. Of course this supply of oil should be regulated, as by means of valves 99 and 99', so that only a tine stream will be drawn through the pipes 98 and 98', and hence only a small quantity will enter the cylinders at each operation, the oil sodrawn in being raised by the piston and forced with the exhausted air through the exhaust-valves of the air-pumps, from which. it may pass by way of pipes 97 and 97' back to the reservoir to be used again. Each piston 83 is shown provided with suitable channels 83' for the passage of the oil and of course may be appropriately packed, as shown at 83".

The pulnps shown herein are stationary on the bed or framework of the machine, and the mold is movable by means of the mold-shifting mechanism hereinbefore described, and hence it will be evident that a suitable movable or flexible connection from the mold-exhausting means to the mold must be provided in the present case. As the connection from the pump P to the mold is the same as from the pump P', a description of the connections from the former will be sufficient for both. Here I prefer to make use of a pipe for establishing this connection, such pipe being indicated herein by lOO and being connected with the pump and with the mold by ball-andsocket joints, as clearly illustrated in Figs. 2, 3, 9, 1l, 12, and let, the ports in the pumpcylinders which lead to the mold having ballsockets, as clearly shown, while the mold-section 0 has corresponding sockets, (indicated herein by 101.) Each pipe is preferably adjustable in length and forms a toggle member, which is straightened out when the mold is closed, and thus tightens the joints and pre- Ventsleakage of the air during the exhaustion of the mold.

Figs. 8, 9, and 11, it will be understood, represent the cylinders as detached from their positions on the machine and the connectingpipes 100 100 removed, showing only the cu pshaped bearings at the outer extremities of the ports 87 and 87', in which the mentioned ball-and-socket connections of the connecting-pipes tit.

For the purpose of exhausting the air from the mold I deem it desirable to provide an opening which will intersect the meeting face of one of two slightly-separated mold-sections, and in this case such an opening is shown in the mold-section o. Here there is preferably a channel-102 in the meeting face the mold and substantiallyconcentric with the mold-space, and from this channel passages, such as 103, may lead to the sockets 101. As before stated, the molds which I employ will IOO IIO

preferably be separable, and I have found that the air can be exhausted most perfectly when it is drawn directly from the meet-ingline of juxtaposed sections. Moreover, with such aconstruction only one mold-section need have outlet-passages for the air and the cen, ical faces at the edges ofthe mold-section may form the air-tight joint.

I have now described, among other things, the various mechanisms and devices by means of Which the mold may beproperly exhausted and molten metalinjected into the exhausted mold; but I have not described any means for cooling and chilling the casting suddenly before it has hardened and is in condition to be stripped from the mold. Any means suitable for the purpose may be used to cool the contents ot' the mold suddenly and check the crystallization thereof; but I prefer to circulate around the casting a cooling medium, such as a stream of cold Water, while the castingis in the mold. Usually this cooling medium will be circulated directly through the mold, preferably th rough one or more of the mold-sections, and in thiscase the sections o and o are subjected to the ac` tion of diiferent circulating streams of Water. The mold-section 0 is cooled and chilled in the present construction by circulating Water through a peripheral groove or channel 105, communicating through pipes, such as 106, with a suitable source of supply, (not showin) While the section o may be correspondingly chilled by circulating the stream through an annular channel 107 in the forward face of the member 7l`of the skeleton frame I-I, (see Fig. 15,) the water being supplied to this channel in substantially the same manner as to the mold-section o. The circulation of these streams of water around the casting during the Whole of the time that the latter is forming results in a very rapid cooling and hardening of the samebefore the metal has had time to form large and Well-defined crysals'. Hence the the result is, as before stated, a casting of much ner grain and more perfectly chilled than when the casting is not subjected to the action of a cooling medium, and, moreover, the formation of the castings is more rapid and a larger product can be turned out in a given time than when the castings are not so chilled.

In connection With the mechanism for separating the several sections of the mold to strip the casting therefrom after the latter has been completed I prefer to employ a mechanicallyoperativecasting-strippersuch,forexample, as that shown herein at s-said stripper in this case Workin g between the tWo main moldsections to strike the sprue of the casting and positively strip and eject the latter from the mold and comprising, preferably, an oscillatory plate, such as 110, secured to a pair of rock-arms, such as 112, pivoted on the frame H, preferably at the point where the yoke 50 is connected to said frame. By referring to Fig. 4 it will be seenthat one of these arms 112 has pivoted thereto a link 113, connected at its rear end to a fixed stop 114 on one of the slide-rods 62, and .hence said stripper is supported on one of the mold-carriers and is operatively connected with the other, the movements of the parts being such that the stripper will be effectivel to strike the sprue of the casting after the mold-carrier h has been retracted to the position shown in Figs. 5 and 1S.

It may happen occasionallythat for some reason-as, for instance, if the parts'are not adjusted properly--themain frame H may not move forward farenough to close the moldsections properly,which,it Willbe noted by referring to Fig. 7, are positively held together by spring-pressure when the antifriction-roll 55 withdraws slightly fromthe cam 56 and it is desirable to provide means for preventing the injection of molten metal into the mold at such a time and the consequent Waste of metal. For this reason I deem itdesirable to make use of a safety device-such,forex ample, as the spring-pressed locking-pawl ll-which will engage a portionof the plunger-operating mechanism of the mold-filling means--as, for example, the stop 29 on the connecting-rod 29-and will not bereleased from such stop unless the mold-sectionscome together properly. To assu re this,I may make use of a paWl-releasing device, such as a plate 116, on one of the mold-carriers--in this case `on themain mold-carrier-which releasing device will cooperate with a face or arm, such as 1151, in fixed relation with the pawl 115, but Willnot strike such arm, and hence will not release the pawl from-the stop 29', unless the main mold-carrier has movedto'its proper position and the mold -seetions have been brought together properly. `The pawl will engage the stop at each operation of the ma chine to forma casting; but it will not be released at any operation unless themold-sec tions are in position to form a perfect casting.

For the purpose of getting the molten metal in the tank M in circulation, thus assuring the presence of an extremely hot and most perfectly fluid metal around the valve fu and in the chamber 8 and the adjacent passages, I deem it desirable to provide an additional supply-passage leading into the chamber 8, preferablyfrom a different portion of the melting-tank than the passage 7 In this case I have shown a series of communicating passages and chambers leading from the upper portion of the tank, Aso as to 'take their sup-` ply from a point somewhat near the top of the molten bath. Here a passage 120 leads into 'a' chamber 121, which is connectedwith another chamber 123 by a passage 122, and from the chamber 123 another passage 124; establishes l communication with the valvechamber S. The iow o f molten metal through these passages and chambers maybe prevented except during the period when the machine is being started, and for the purpose of cutting off the supplyand yet permitting accu- IOO IIO

mulated air and gas to escape I may make' use of a valve, such as 125, substantially similar to that shown at 5., Before the casting operation begins, however, this valve may be opened, while the lever 43 is up and the valve@ remains closed, and the machine may be started, which of course will result in circulating the metal not only through the passages 7 and 8' into the `chamber 8 from the bottom of the bath, but also through the passages just described' from a point near the top of the bath, thus assuring a very perfect circulation of the metal in the tank and in the chamber S before the actual casting operation begins. The principalfunctions of this valve 125, however, are to prevent the lowering of the pressure of the jet of molten metal, the cushioning of its blow, and the formation of blow-holesin the casting, all of which would result from the accumulation of air and gas in the chamber S.

The operation of a casting-machine constructed in accordance with my present invention as hereinbefore set forth is as follows: The valve 125 will be opened while the lever 43 remains up, whereupon the machine will be started and the driving-wheel permitted to make a few rotations in order to get the molten metal in circulation, and thus assure the filling of the chamber 8 with hot and perfectly fluid metal. Thereupon the valve 125 may be closed again and the lever 43 pushed down to permit the valve o to be operated by wiper 40, all this being merely preliminary to the operation of the machine for forming a casting. Assuming that all of the parts are are in their normal positions-that is, with the valve v closed and the sections of the mold in their open positions relative to one another, as shown in Fig. 5-the driving-wheel 3 and the shaft 2 will be rotated in the direction of the arrow, and as the antifriction-roll 55 rides down the face of the cam 56 the spring 59 will shift the frame H toward the opening 10 and at the same time slightly elevate said frame to bring the sprue-hole into position to register with such opening, although the frame 7?, will not at first move toward the opening 10, but will merely rise, owing to the fact that the springs 66 will be effective to keep the slide-rods 62 in contact with the stopfacesS until the main frame H reaches the position shown in Fig. 6 and becomes effective to actuate said frame h and its mold-section positively, the shifting of the frame H in this direction being effected by a spring 59 and said frame being firmly pressed forward as the antifriction-roll 55 leaves the face of the cam 56. Hence said spring 59 exerts at such time a constant pressure upon these frames and tends to press the mold-sections o and 0' firmly together and also to hold the nipple 18 tightly against the nozzle 12. Before the mold-sections o and o' close, however, the antifriction-roll 77, rising from the cam 78,permits the spring 76 to become effective to shift the bar 7L' toward the opening 10 Thereafter and while the mold-sections are closed the cams 95 and 95 on the shaft 2 will operate successively to raise the

puppetvalves

86 and 86,and thus first partially and afterward completely exhaust the mold, the valves S6 and S6' opening and closing successively and the pistons then rising inthe pump-cylinders to force out through the

pipes

97 and 97 the air exhausted from the mold and also the oil in said cylinders. By this time the block 30 will have slipped off the face of the cam 33, and the spring 32 will be effective to force down the plunger p and set in motion the metal in the passage 7 and the chamber 8, and the kinetic energy of the moving metal will when the valve c is opened serve as an additional means for forcing the jet of molten metal into the exhausted mold. The cam 41is so located as to open this valve o (see Fig. 7) before the plunger reaches the limit of its downward movement, and hence as the valve o opens the passage 10 and closes the passage 8/ the whole force of the plunger will be added to the m's wird of the moving body of metal. to force a stream of molten metal under very high pressureinto the closed and exhausted mold. This molten metal will be cooled and chilled almost instantaneously as it enters the mold, owing to the circulation of the streams of water around thel mold-sections, and the tendency of the cooling body to crystallize will be checked and a very high grade casting with an extremely line crystalline structure will result. As soon as the proper amount of metal has been supplied to the mold the valve o Will close again and the plunger p will rise, and thereupon the mold may be opened; but before the mold-sections separate the auxiliary or admission valve 8S, carried by the puppet-valve 86, will open communication between the outer air and the mold in order to facilitate the separation of the mold-sections. Thereupon the antifriction-roll 55 will ride up the face of the cam 56 and retract and l'ower the main frame H, the rst movement being to the position shown in Fig. 16 to withdraw a portion of the sprue of the casting c from the opening 10, whereupon the ends of the slide-rods 62 will again strike the stop-faces 68, and the frame l?, will be at the rearward limit of its slight reciprocatory movement. The main Y frame H, however, will continue to move to the rear, as seen in Figs. 5 and 17, and the major portion of the casting will be stripped from the mold-that is to say, it will be IOC) IIO

stripped from the mold-section o. When the antifriction-roll 77 comes into contact with the cam 78, theframe h will beshifted to the rear to strip the mold-section o from the casting, as shown in Figs. 5 and 18. If the casting still adheres to the mold-section 0', as Will frequently be the case, the stripper .s

Will then strike the sprue of the casting c and strip the last portion of the engaged surface away from the mold, whereupon the casting will drop and may be received ina suitable receptacle, (not shown,) the stripper being afterward retracted from its position between the mold-sections by an upward movement. It should be understood, of course, that the valve 88 Will have closed before the pumps become effective tov exhaust the mold again during the next cycle of operations of the machine. Each time that the plunger reaches the limit of its upward movement the stop 29m will be engaged by the pawl 115, and if the mold-sections come together properly the paWl-I'eleasing plate 116 will strike the arm 115 and release said pawl to permit the plunger to descend again; but if the mold-sectionsdo not come together properly the pawl will not be released, the plunger will not descend, and there will be no Waste of the molten metal.

Having described my invention, `I claim- 1. In a casting-machine, the combination with means for subjecting a mass of molten met-al to a pressure greater than atmospheric, and a mold, of a plurality of` air-pumps for producing a vacuum in the mold; a valve for controlling the entrance to the exhausted mold of molten metal; a power-driven device in the machine; and mechanism operatively connected with such device which first renders one of the air-pumps effective to exhaust the mold, then renders such pump ineective and a second pump effective to further exhaust the partially exhausted `mold, and finally during the second exhaustion actuates the said valve and thereby admitsmolten metal under pressure to themold.

2. In a casting-machine, the combination with means for subjecting a mass of molten metal to a pressure greater than atmospheric, and a mold, of a plurality of air-pumps communicating with the mold for producing a vacuum therein; valves controlling the passage-Ways leading from the air-pump cylinders to the mold; a valve for controlling the entrance to the exhausted mold of molten metal; a power-driven device inthe machine,

` and mechanism operatively connected with such device, which first` actuates the pistons of the air-pumps, and opens the valve in the ducing a vacuum therein; valves controlling the passage-Ways leading from the air-pump cylinders to the mold; a valve for controlling the entrance to the exhausted mold of molten metal; a power-driven device in the machine; and mechanism operatively connected with such device, which first actuates the pistons of the air-pumps and opens the valve in the passage Way leading from one of the airpump cylinders to the mold, then closes this latter valve and opens the valve in the passage-way leading from a second air-pump cylinder, and finally, before the piston of the last-mentioned cylinder has reached the end of its stroke, actuates the plunger and opens said valve controlling the flow of molten metal to the mold. 4 n

` 4. In a casting-machine, the combination with means for subjectinga rnass of molten metal to a pressure greater than atmospheric, a mold, and an'air-valve for admitting air to the mold at a predetermined time, of a plurality of air-pumps for producing a vacuum in the mold; a valve for controlling the entrance to the exhausted mold of molten metal; a power-driven device in the machine; and

mechanism operatively connected with such` device which first renders one of the" airpumps eective to exhaust the mold,`then renders such pump inedective anda second pump effective to further exhaust the partially-exhausted mold, then during the second exhaustion actuates the said metal-controlling device and admits molten metal to the mold, and inallyopenssaid air-valve and admits air to the mold.

5. In a casting-machine, the combination with means for subjecting a mass of molten metal to a 4pressure greater than atmospheric, a mold, and an air-valve for admitting air to the mold at a predetermined time, of a plurality of air-pumpscommunicating With the mold for producing a vacuum therein;` valves controlling the passage-ways leading from the air-pu mp cylinders to the mold; a valve for controlling the entrance to the exhausted mold of molten metal; a power-driven device IOO IIO

in the machine; and mechanism operatively 4 connected with such device which rst actu` ates the pistons in theair-pumps and opens `the valve in the passage-Way leading from one of the air-pump cylinders to the mold, then closes this latter valve and opens the valve in the passage-Way leading from a second cylinder to the mold, then, before the piston of thelast-mentioned cylinder has reached the end of its stroke, opens the said metalcontrolling valve, and finally opens said airvalve and admits air to the mold.

G. In a casting-machine, the combination with a plunger for subjecting molten metal to pressure, a mold, and an air-valve for admitting air to the mold at a predetermined ti mc,

ILO

of a plurality of air-pumps communicating with the mold for producing a vacuum therein; valves controlling the passage-ways leading from the air-pump cylinders to the mold;

a valve for controlling the entrance to the exhausted mold of molten metal; a power-driven device in the machine; and mechanism operatively connected with such device which first actuates the pistons of the air-pumps and opens the valve in the passage-way leading from one of the cylinders to the pump, then closes this latter valve and opens the valve in the passage-Way leading from a second airpump cylinder to the mold, then, before the piston of the lastmentioned cylinder has reached'the end of its stroke, actuates the plunger and opens the said metal-controlling valve, and finally opens said air-valve and admits air to the valve.

7. In a casting-machine, the combination with a plunger for subjecting molten metal to pressure, and a mold, of a plurality of airpumps communicating with the mold for producing a vacuum therein; valves controlling the passage-ways leading from the air-pump cylinders to the mold; a valve for controlling the entrance into the exhausted mold of molten metal; a main shaft from which the pistons of said air-pump cylinders are actuated; and a series of cams operatively connected to the shaft, and with said plunger and the valves in the passage-ways leading from the air-pump cylinders, and with said metalcontrolling valve, and which actuate the same in the following order during the exhausting movement of the pistons, namely: first the valve in one of said passage-ways to open the same, then this valve and the valve in another of the passage-ways to close the first valve before opening the second, and finally the plunger and the metal-controlling valve to admit molten metal under pressure into the mold.

8; In a casting-machine, the combination with 1a plunger for subjecting molten metal to pressure, a mold, and an air-valve for admitting air at a predetermined time to the mold, of a plurality of air-pumps c ommunicating with the mold for producing a vacuum therein valves controlling the passage-ways leading from the air-pump cylinders to the mold; a valve for controlling the entrance into the exhausted mold of molten metal; a main shaft from which the pistons of said air-pump cylinders are actuated; and aseries of cams operatively connected to the shaft, and with said plunger and the valves in the passage-ways leading from the air-pump cylinders, and with said metal-controlling valve, and which actuate the same in the following order during the exhausting movement of the pistons, namely: first the valve in one of said passage-ways to open the same, then this valve'and a valve in another of the passage-ways to close the rst valve before opening the second, then the plunger andthe metal-controlling valve to admit molten metal under pressure into the mold, and finally the air-valve to admit air into the mold.

9. In a casting-machine, the combination with a separable mold, of means for first producing a vacuum in the mold; means for next causing the filling of the mold with molten metal; means for afterward admitting air to the mold; means for finally separating the mold; and mechanism for causing the operation of the several means in the order specified.

lO. In a casting-machine, the combination with a separable mold, of a plurality of separate means for producing a vacuum; means for causing the filling of the mold with molten metal; means for admitting air to the mold; means for separating the mold; and mechanism operatively connected to the machine for actuating the aforesaid means in the following order, to wit: to first render one of said vacuum-producing means effective to exhaust air from the mold, then to connect the partially-exhausted mold with a second vacuumproducing means, then to cause the injection into the mold of molten metal, then to admit air to the mold, and finally to separate the mold.

1l. In a casting-machine, the combination with a separable mold, of a plurality of sepa-v rate means embodying a pair of air-pumps for producing a vacuum; means for causing the filling of the mold with the molten metal; means for admitting air to the mold; means for separating the mold; and mechanism operatively connected to the machine for actuating the aforesaid means in the following order, to wit: to first render one of said airpumps effective to exhaust air from the mold, then to connect the partially-exhausted mold with the other air-pump, then to cause the injection into the mold of molten metal, then to admit air to the mold, and finally to separate the mold.

12. In a casting-machine, the combination with a mold and with mold-filling means, of an air-pump embodying a main puppet-valve controlling communication between the pump-cylinder and the mold, and an auxiliary valve carried by the lnain valve and controlling communication between the mold and the outer air. A

13. vIn a casting-machine, the combination with a mold and with mold-filling means, of an air-pump; a main valve controlling communication between the pump-cylinder and the mold; an auxiliary valve vcarried by the main valve and controlling vcommunication between the mold and the outer air; and a valve-actuating mechanism for operating the main and auxiliary valves with relation to each other.

14. In a casting-machine, the combination with a shiftable mold having mold-sections adapted to move toward and away from each other transversely to the plane of their surface of contact and provided with a `groove intersecting said surface, of a nozzle through ICO IIO

a flexible connection extending between the mold and the air-pump cylinder and communicating with said groove.

15. In a casting-machine, the combination with a mold having mold-sections adaptedvto move toward and away from each other transversely to their surface of contact and provided with a groove intersecting said surface, of mechanism for separating the mold-sections upon the filling of the mold, a conduit communicating with the groove through which air is exhausted from the mold; a valve for controlling the admission of air to the groove; means for applying a pressure to molten metal in the machine to edect its forcible injection into the exhausted mold; and mechanism for operating said valve to admit air into themold after the injection of the metal thereinto. i

16.v In a casting-machine, the combination with a discharge-nozzle, and an air-pump cylinder, of a mold shiftable relatively to the cylinder and to the'discharge-nozzle; means for guiding the mold, and for advancing the same into a casting position inwhich it contacts with said nozzle, and forwithdrawing it from such position; a flexible connection extend` ing between the mold and the air-pump cylinder; and mechanism operatively connected to the machine which rst causes the advance of the moldtoward the nozzle, then the eX- haustion of the mold, 'and nally the injection of molten metal into the exhausted mold.

haustion of the mold, then the injectionot` molten metal into the exhausted mold, and finally the admission of air to the mold subsequent to the injection of metal thereinto.

18. In a casting-machine, the combination with a discharge-nozzle, and an air-pu mp cylinder, of a sectional moldshiftable relatively to the cylinder and to the discharge-nozzle; means for guiding the mold, and for advancing the same into a casting positionin which `it contacts with said nozzle, andfor-withdrawing it from such position; a iiexibleconnection extending between themold and the l air-pump cylinder; and mechanism operatively connected to the machine which iirst causes the advance of'the mold toward the nozzle, then the exhaustion of the mold, then the injection of molten metal into the exhausted mold, and inally the withdrawal of the mold from the nozzle, and its separation.

19. In a casting-machine, the combination with a discharge-nozzle, and an air-pump cylinder, of a sectional mold shiftable relatively to the cylinder and to the discharge-nozzle; means for guiding the mold in its movements, and for advancing the same intoa casting position in which it contacts with said nozzle, and for withdrawing it from such position; an air-admission valve; a iiexible connection extending between the mold and the airpump cylinder; and mechanism operatively connected to the machine which first causes the advance of the mold toward the'nozzle, then the exhaustion of the mold, then the injection of molten metalinto the exhausted mold, then the admission of air to the mold subsequent to the injection of metal thereinto, and finally the withdrawal of the mold from the nozzle, and its separation.

. 20. In a casting-machine, the combination with a discharge-nozzle, and a pair of airpump cylinders, of a sectional mold shiftable relatively to the cylinders and the dischargenozzle; means for guiding the mold in its movements, and for advancing the same into a casting position in which it contacts with said nozzle, and for withdrawing it from such position; an air-admission valve; flexible connections extending between the `mold and the air-pump cylinders; and Vmechanism operatively connected to the `machine which first causes the advance of the mold toward .the nozzle, then the exhaustionof the mold, then IOO A the admission of air into the mold subsequent to the injection of metal thereinto, andlinally the withdrawal of the mold from the nozzle, and its separation. .l

2l. In a casting-machine, the combination with a discharge-nozzle and an air-pump cylinder, of a sectional mold shiftable relatively `to said cylinder; means for guiding the mold in its movements and for advancing the same to a casting position in which it contacts with said nozzle and for withdrawing it from such position; an air-admission valve for said cylinder; means for positively operating such valve; means for separating the sections of the mold from each other and a flexible con- ,with said nozzle, and forwithdrawing it from such position; a main valve for admitting air from the mold to `the air-pump cylinder; an air-admission valve carried by the main valve for admitting air to the mold before its with- IIO IIS

drawal and separation and a iiexible connection extendingbetween and connecting-the air-pump cylinder with the mold.

y 23. In a casting-machine, the combination with a discharge-nozzle, and two air-pu mp cylinders, of a sectional mold shiftable relatively to said cylinders; means for guiding the moldin its movements, and for advancing the same Yinto a casting position in which it contacts with said nozzle, and' for withdrawing it from such position; an air-admission valve; iiexible connections extending between and connecting 4the air pump cylinders with the mold; and mechanism operatively connected to themachine which first causes the advance ofthe mold toward the nozzle, then the exhaustion of the mold, then the admission of a plurality of-air-pumps forproducing a vacu- 'umin the mold, of means for shifting the direction of flow of the molten metal; a powerdriven device in the machine; and mechanism operatively connected with such device which renders one of the air-pumps effective to partially-exhaust the mold, said pressure means effective vto establish the flow in the meta-l and the operating-pump subsequently ineffective and a second pump eifectivefto further exhaust the partially-exhausted mold;

:and then, subsequent to the establishment of the Vflow,actuates the means for shifting the Idirection of suchY movement, thereby effecting the diversion of the flow toward and into the mold.

25. Ina casting-machine, the-combination with a melting-tank and a chamber connected to the tank and normally shut off from communication with the mold, of means for subjecting a ma-ss of molten metal communicating with'that in the chamber to a pressure greater than yatmospheric and thereby set up 'a movement in' the body of metal in the chamber outward-into the tank; means for suddenly vopening communication between the chamber and the mold and for simultaneously arresting the flow of metal from the chamber into the tank; a plurality of air-pumps for vlproducing a vacuum in the mold; a power- ,driven device in the machine; and mechanism operatively connected with such device which rendersone of the air-pumps eective to partially exhaust the mold, said pressure means effective toestablish the flow of the metal in the chamber and the operating-pump `subsequently ineffective and a second pump effective to further exhaust the partially-exhausted mold; and then, subsequent to the establishment of such flow,actuates the means yforopeningcommunication between the chamber andthe mold and simultaneously arrest- 4ing the iow of metal in other directions, thereby diverting the direction of flow toward and into the mold.

26. In a casting-machine, the combination vwith a melting-tank, a mold and a chamber in'normal communication with the tank, of means for subjectinga mass of molten metal communicating with that in the chamber to a pressure greater than atmospheric and thereby set up a movement in the body of metal in the chamber outward into the tank; a valve for closing communication between the chamber and the tank; a valve for controlling the inlet of molten metal to the mold from the chamber; a plurality of air-pumps for producing avacuum in the mold; a power-driven device inthe machine; and mechanism operatively connected with such device which renders one of lthe air-pumps eifective to partially-exhaust-the mold, said pressure means 'effective -to establish the fiow of the -metal in the chamber, and the operating-pump sub- A sequently ineffective and a second pump effective to further exhaust the partially-exhausted mold;"and then, subsequent to the Vestablishment of such flow, actuates said Avalves to thereby close communication between the chamber and the tank and simultaneously open communication between the chamber and the mold.

27. In a casting-machine, the combination with a melting-tank; a mold and a chamber in normal communication with the tank, of means for subjecting a mass of molten metal communicating with that in the chamber to a pressure greater than atmospheric and thereby set up a movement in the body of metal in the chamber ou tward into the tank; a doubleaction valve for controlling communication between the chamber and the mold and -the chamber and the tank; a plurality of airpumps for producing a vacuum in the mold;

a'power-driven device in the machine; and mechanism operatively connected with such device which renders one of the air-pumps eifective to partially exhaust the mold, said pressure means effective to establish the flow Jof the metal in the chamber, and the operating-pump subsequently ineifective anda second pump effective to further exhaust the `partially-exhausted mold; and then, subsequent to the establishment of such flow, actuates-said valve to thereby simultaneously close communication between the chamber and the tank and open communication between the chamber and the mold.

28. In a casting-machine, the combination IOO IIO

with means for'subjecting'a mass of molten metal to a greater pressure than atmospheric;

means for holding the metal and permitting it to iiow in consequence of such pressure in -a ldirection other than into the mold; a nozzle; a shiftable mold; means for shifting the mold toward and away from the nozzle; and a plurality of air-pumps for producing a vacu-