US1913071A - Apparatus for pouring melted metal under pressure - Google Patents

Description

l June 6, 1933- R. v. cHRlsTENsEN yErr AL 1,913,071

APPARATUS FOR POURING MELTED METAL UNDER PRESSURE Filed Jan. 2, 1951 2 Sheets-Sheet 1 Inventors i@ M M M 5f Ama/L4 ,0M/La, /lforneys June 6, 1933. R. H. v. cHRlsTl-:NSEN Er AL 1,913,071

APPARATUS FOR POURING MELTED METAL UNDER PRESSURE Filed Jan. 2, 1931 2 Sheets-Sheet 2 3 Z2- 7 W (y.

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Y AMM 4 zum 4% M4 Patented .lune 6, 1933 UNITED STATES PATENT ori-lcs BEINHABDT HARALD A PPABA'TUS FOB POUBING HELTED METAL UNDER PRESSURE Application lled- January 2, 1931, Serial No.

`This invention aims to provide an improved process and apparatus for pourlng molten metal, such as iron, phosphor-bronze and aluminium under pressure.

In castings of this nature it is known to withdraw the molten metal from the crucible by means of a pourin ladle, which is then connected to the moul The process according to the present invention is distingulshed from -this in that the metal isA transferred from the ladle to the mould bythe creation in the mould of a relatively low differential pressure, for instance a vacuum, that the inlet of the mould is then closed, and that the metal enclosed in the mould is then exposed to a pressure. According to the 1nvention the vacuum in the mould may be produced by the air in the mould being sucked out at several points.

The apparatus according to the invention is partly characterized in that a portion of the inlet of the mould is formed by a cylindrical channel adapted to receive a piston, which piston, when moved forward towards the mould cavity, first closes the connection to the latter and then exerts a pressure on the. enclosed metal. Other distinguishing features of the apparatus will appear from the foilowing description of various practicable embodiments of the invention as shown in the drawings, wherein Fig. 1 lillustrates a casting machine, in side elevation, partly in section,

ig. 2 is a top view of the same, ig. 3 illustrates another constructional form of casting machine in side elevation,

partly in section; and

Fig. 4 is across-section of the latter on the line IV``IV of Fig. 3, showing associated valve mechanism employed vin both constructions.

The casting machine shown in Figs. 1 and 2 embodies a frame 10 fitted at the ends with brackets` 11 interconnected by round bars 12 serving as guide bars. Two holding `plates 13 and a holding member 14 are adapted to slide on these bars, and the member 14 is adjustably connectedto one of the holding plates 13 y means of threaded sleeves 15 provided on the bars 12. The parts 16 506,280, and in Denmark January 7, 1980.

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of the mould areconnected to or between the holding plates 13 in such positions that the mould parts will engage one another correctly, when the holding plates are drawn toward one another. In one of the brackets 11 a shaft 17 is journaled, which shaft supports two toothed segments 18 engaged by pinions 19, which are mounted on another shaft 20 journaled in the same bracket and actuated at one end b a capstan wheel 21. Arms 22, integral wit the segments 18, together with length-adjustable link members 23 form knee-presses adapted to actuate the holding member 14 when the capstan 21 is rotated.

At one end of the casting machine a vfurnace 24 is provided, containlng a crucible 25, in which the casting material is heated.

The transfer of the molten metal to the mould 16 is effected by a pouring ladle 26 which in the present instance is made of a vrefractory material shaped like a block and having a mainly U-shaped channel 27 adapted to hold the mould charge. This ladle is suspended with free pivoting on a crank 27', the shaft 28 of which is journaled in a bracket 29 attached to one of the brackets 11 and adapted to be actuated by means of a crank handle 30. For transferring the ladle from the crucible to the mould,v the shaft 28 is turned through an angle of 270 b the handle 30, whereafter the ladle will in the position shown in Fig. 1. In this position, one orifice of the channel 27 communicates with the inlet 31 of the mould by way of a refractory lining 32 inserted in one of the holding plates 13. The other orifice of the channel 27 communicates with the at-` mosphere by lway of a sleeve 33 forming a resilient support for the ladle 26, as the sleeve 33 is adapted to slide in the above mentioned bracket 11, counteracted by a spring 34. When the pouring ladle is situated in theI above mentioned osition, then the mould parts 16 are moved) together by means of the aforedescribed knee- presses 22, 23 actuated b the capstan 21. When the mould parts ave come into contact with one another, they are moved to ether a short distance by further rotation o the capstan,

. determined by the tension of the sprin 'until the front holding plate 13 strikesa suitable stop. During this last motion the` ladle 26 is pressed firmly between the lining 32 and the sleeve 33 under a pressizie B thismeans it is assured that the la e 26 will not be subjected to excessive lateral pressures or stresses. .The liquidmetal taken up in the channel 27 of the ladle is drawn. in to the cavity 35 of the mould b a vacuum created in the latter. From t e mould cavity a .channel 36 extends, whichl at the start is situated in the dividing surface between the `mould parts, i. e. half of the channel is worked into -each mould part, and then `the channel is continued in the foremost mould part 16 (situated next to the furnace 24) From the channel 36 extends a flexible pipe` 37, which by way of a valve 38 leads to av suction pump (not-shown g If desir the liquid metal may also be transferred to the mould by supplying compressed air, at a relatively low pressure to the sleeve 33 on the other side of theladle A portion of the inlet of the mould is formed by a cylindrical channel 38 adapted to receive a rod-like plunger 39 which latter when moved forward towards the mould cavity 35, first cuts off thev connection from p the pouring ladle 26 to said cavity, and then exerts a pressure on the enclsed metal. The axis of the plunger 39 is mainl situated in the dividing plane of the moul in 'such amanner that the solidified plug of metal below the lunger can be removed together with the ead head inthe inlet, when the mould parts are separated at the removal of the casting. t i

'The' plunger 39 supports at lts extreme end a disc 40 forming the piston for a cylinder 41, to the top part of which compressed air can be supplied by way of a 'valve 42 and a pipe 43 from a not shown source of compressed air, when said piston is to Alie-moved inward. The cylinder 41 is sup rted by a bracket 44 attached to the front olding plate 13, so that the cylinder is always in firm connection with the fore? most mould part 16. The piston 39' will therefore continue to be inl contact with this mould part, when the other mould part is withdrawn during removal'of the casting. To the rear holding plate 13 there is attached an arm 45, the extreme bent end of which co-operates with a stop "46 on the plunger 39, whenthe said holding plate is moved back, so that the plunger 1s` automatically returned to the initial positionv l'when the mould is opened.-

The valves 38 and 42 are conveniently mounted in a bracket affixed to the front holding plate or frame, with the first-named -'(38) thereof controlling a connection of the pipe 37 with a pipe 72 leadin ,to the aforetageously-controlled by a common device which in the illustrative example is forme by a two-armed lever 47, which is pivoted on a pin 48 and one arm of which co-o erates with the spindles of the valves, whi e the other arm is adapted tobe actuated from v the rear end of the casting machine by a cord or chain 49. By this arrangement the advantage is attained that the two valves are always o rated jinproper succession, the valve 38be1ng opened first and then the valve 42.

It should be noted thatl the first art of the exhaust channel 36 is so narrow t at the melted metal vwill 'solidify from` cooling against the form parts l16 before assing any appreciable distance into this c annel, which will therefore become clogged. Accordingly, the melted metal cannot possibly be suckedv out through the pipe 37.

The modification or construction of the casting machine shown in Figs. 3 and'4 will now be described in so far as it differs from that just described.

the rear holding plate 13 and the mold part .16 supported y the same,l a 'su orting member 51, whereby space isprovi ed for a not shown mechanism serving to withdraw any cores used in connection with the mould. The front holding plate 13 is stationary, and is constructed as a bracket attached directly to the frame 10. f

The-melted metal is supplied to the mould by way of 4an angular inlet pipe 52 made preferably from refractory material. This pipe is placed in such manner that one branch thereof is vertical and the other one horizontal. The horizontal branch passes air-tight through the front holding plate 13, against which the corresponding mould part 16 is pressed air-tightly, and lends ata cavity 53 in the mould, from which cavity the inlet proper 54to the cavity 35 of the mould extends. The outlet orifice from the horizontal branch opens to the inlet 54. The

inlet orifice at the free end of the vertical avslit. 57 or the horizontal branch of the inlet pipe and, along a' horizontal plane some In this machine there is inserted, between i 4u of the miaou distance abovev the bottom, lone or more openings 58 determining the to level of the quantity of metal contained 1n the pipe.

The pi 56 is suspended on a mechanical A `l moving evice actuated automatically by the of the movablemould part towardsthe stationar mould part the pipe'56 will be raised to suoli a level that just one mould charge will be taken up to be transferred from this pipe to the inlet pipe 52 by suction through the last mentioned pipe. The distance between the liquid level in the raised pipe v56 and the downward. facing orifice of the pi 52 is in fact the feature determining t e quantity of metal to be transferred to the mould, because when the liquid level reaches the said orificel the intake of metal will cease, l whereafter only the column of metal con tained in the pipe 52 will be conveyed to the mould owing toits kinetic energy.

`In this modified construction as shown 1n Fig. 4, the piston 39 and the cylinder 41 are 35 disposed in sloping manner, in order to provide space for the end of the pipe 52 situated in the cavity 53. V

TheV channel by way of which the mould is evacuated is in this case ramified and con- 0 nected to the mould vcavity 35 at several points. Hereby any accumulation of' air in v the mould during the pouring will be avoided, and the effect of any leaks will be eliminated. The ramification is effected by cut- 5 ting furrows or grooves 63 in the contacting surfaces of the `mould parts, which grooves when the mould parts are placed together form a channel, which encircles all the cavities 'of ythe mould, and from Where branches 64 extend to the said cavities. The annular channel is connected to the suction line 37' by Way of the channel 36 in the front stationary mould part 16.

The machine isotherwise constructed in 55 similar manner to that first described, and the corres onding parts in the two machines are mar ed with the same reference numerals.

In this construction of the machine the 6 liquid metal transferred by way of the pipe 52 will first be received by the cavity 53, which is sufficiently large to hold the entire mould charge. From this cavity the metal is conve ed to the mould cavity, mainly by 05 action o gravity alone.

art. The screw 62 can be adfv 'The here describedconstructions may be modified 1n various respects without deviation from the essential features of the inention. `Thus the iston which `limits the mould charge recelved by the mould and exerts a pressure thereon may be moved by purely mechanical means, such as a screw or the like, instead of the valve mechanism shown and described in detail with reference to Figs. 1 and 2. y i

vThe advantage of the process accordin to the present invention is not only that allbys and metals with high melting point and being difficult .to pour can be cast, but lalso denser and more uniform .castings are attained than according to the here known squirting method of casting, accord- 1ng to which a metal superheated above the fusmg point is flung forcefully into the moul By this last mentioned casting method the introduction of the metal is so `violent thatv it is flung against the walls of the mould in such a' manner that at certain points the air in the mould may become enclosed, while the metal, where the wall' is thin, may become solidified before the entire pouring is finished, the consequence be- .ing that the advantages of the pressure used cannot manifest thelnselves. The castings will therefore be porous and less uniform. and may contam air blisters. These drawbacks may certainly be avoided by another.

known casting method, i. e., the so-called chill casting, which method, however, is not suited for mass-production and does not give so fine and sharp castings as does lthe squirting method. A' distinguishing feature of th rocess according to the present method is tfi at the metal is introduced into the mould by a rela? tively loW differential pressure, so that the conditions will be approximately the same as if the metal were poured' into4 the mould, and that the metal is then exposed to a considerable pressure, so that it will fill the mould entirely. The use of a high pressure on the metal, after the same is introduced into the mould, is mainl rendered practicable by the feature that t e pressure does not act on the ladle.

Having now particularly described and ascertained the nature of our invention and in what manner the same is to be performed `We declare that what We claim is:

1. In an apparatus for casting metal under pressure, a mould, a ladle adapted to receive molten metal and to be subsequently connected with the mould, an inlet channel in the body of the mould arranged to colnmunicate with the ladle when the latter is connected with the mould and situated above the mould cavity so as to allow the molten metal to be transferred against the action of gravity from the ladle to said inlet channel and to fill the mould cavity by gravity,

a second'channel situated in the body o f the mould and communicating with said inlet channel, and a plunger arranged to advance in said channel so as to cut of the flow of 5 the molten metal from the ladle to the inlet channel and to subsequently subject the metal in the mould to pressure.

2. An apparatus for castin metal under pressure, comprisin a mou d formed, in

10 two parts, an inlet c annel for molten metal disposed in the body of the mould above the mould cavity, a ladle adapted to receive molten metal and to be connected with the mould so as to communicate with said inlet channel of the latter by an upwardly disposed passage through which the metal may be transferred from the one to the other against gravity action, a channel formed by the two parts of the mould and communicating with said inlet channel, and a plunger arranged to advance in the lastnamed channel so as to cut olf the flow of the molten metal from the ladle to the mould and to thereafter subject the metal in the mould to pressure.

3. An apparatus for casting molten metal under pressure, comprising a mould formed in two parts, an inlet channel. in one part of the mould above the mould cavity, a channel formed by the two parts of the mould in communication with said inlet channel, a ladle adapted to receive molten "metal and to be connected with the mould, communicating passages with -means for forcing the molten metal from the ladle into said inlet channel against gravity action and to allow the molten metal thereafter to fill the mould cavity by gravity, a plun er located in the second-named channe and means for advancing the plunger in said second-named channel so as to first cut off the molten metal suppl from the ladle to the mould and then subject the molten metal within the mould to pressure.

4.l An apparatus for castin molten metal under pressure, comprising a mould formed in two parts, an inlet channel in one of said parts at a level higher than the mould cavity, another channel formed lin the two parts of the mould and communicating with said inlet channel, a ladle adapted to receive molten metal and to be connected with the mould in an upward passage communication with said inlet channel thereof, an evacuating channel in the mould body communicating with said mould cavity and therethrough with said inlet channel, means for creating a vacuum in the mould through the evacuating channel to draw the molten metal. from the ladle into the inlet channel of the mould a inst gravity action and allowing the meta to flow from said inlet channel into the mould by gravity, means for interrupting the vacuum action, a plunger working in the 5 second-named channel, and means for mov- Vof molten metal from the ladle to the inlet channel and then to subject the moltenpmetal fed into the mould cavity to pressure.

5. An apparatus for casting molten metal under pressure, comprising a mould formed in two parts, an inlet channel in one .of said arts at a level higher than the mould cavity, a cylindrical channel formed by the two parts of the mould and communicating with said inlet, a ladle adapted to receive molten metal and to beconnected with the inlet of the mould through an upwardly directed passage, an evacuating channel in the mould body -coinmunicating with the mould cavity, meansv for creating a suction through said evacuating channel to draw the molten metal against gravity action from the ladle into the inlet channel of the mould and allowing the metal to flow from said channel into the mould by gravity, a plunger working in the cylindrical channel, means for interrupting the suction action and means for moving said plunger to first cut off the iow of metal from the ladle to the inlet channel and then to subject themolten metal in and flowing to the mould cavity from the inlet channel by gravity to pressure.

6. An apparatus for casting molten met-v al under pressure, comprising a mould formed in two parts, an inlet channel in the body of the mould above the mould cavity, an angular inlet pipe projecting into said inlet channel through an airtight seal, a ladle encircling the lower end of a downwardly directed portion of said inlet pipe and arranged to receive predetermined amounts of molten metal, means for adjusting the ladle vertically to cause the molten metal therein to surround the lower end of said pipe (portion, an evacuating channel in the moul body communicating with the cavity of the mould, means for creating a suction in the mould through said evacuating channel to draw the metal through said inlet pipe from the ladle to the inlet channel of the mould, a cylindrical channel formed by the two parts of the mould in communication with the inlet channel, a plunger working in saidl cylindrical channel, means for interruptin the suction action in the mould when su cient molten metal has been drawn thereinto, and means for thereafter circling the lower end of a downwardl dilrected portion ofsald inlet pife an ar- 1 to receive predl'atermine quantities `of molten metal, means for adjusting the -l F ladle verticali to bring the molten metal therein aroun the lower end of said pre l rtion, an evacuating channel in the mo d y in cmmun'ication with the mould cavity, means for creating a suction -in the 1 0 mould through said evacuating channel to draw the metal from the ladle through the inlet pi to the inlet channel ofthe mould, a cylm rical channel formed by the two parts of the mould in communication with the inlet channel, a plunger working in said c lindrical channel, means for interruptin t e suction action 1n the mould when allE cient of the moltenmetal has been drawn thereinto and means 'for thereafter causin the aforesaid plunger in the cylindrica t channel to advance to first close the connec tion between the angular tube and the mould cavity and to then subject the metal in the latter to pressure. 8. An apparatus for castin metal under pressure, comgrising a mould ormed in two parts of whic one is stationa means for moving the other part to andv rom the stationary part, a `ladle adapted to receive 9 molten metal and movable automatically in cogeration with the aforesaid means to a etermined raised position when the mould parts are brought together,I an inletA channel in the mould, an an ular pipe having one branch fitted airti t in the inlet channel of the mould and t e other branch extended downwardly into the lower` end of K the ladle, an evacuatin channel in the mould body communicating with the cav- 4 ity of the mould, means for Aerecting a suction in the mould through said evacuating channel to draw the metal from the ladle through the angular pipe to the inlet channel of the mould, a cylindrical channel formed by the two parts of the mould in communication with the inlet channel,` a dplunger working in said cylindrical channel, means for interrupting the suction in the mould when suihcient molten metal has been drawn thereinto, and means for thereafter causing said plunger to advance in its cylin.- ldrical channel tocut oli' the molten metal dow from the ladle to the mould cavity and I to then subject the metal in the mould to pressure. A

REINHARDT HARALD VALDEIAR CIIRISTERSEN. RICHARD Sllfll-l DAHL. v

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