US2338560A - Centrifugal casting apparatus - Google Patents

Description

Jan. 4, 1944. H G YARUSS 2,338,560l

GENTRIFUGAL CASTING APPARATUS Filed Dec. `2, 1942 2 sheets-sheet 1 mveutor Hmew G. www.;

Gttorneg Jan. 4, 1944. H. G. YARUSS 2,338,560

yCENTRLFUGAL CASTING APPARATUS Filed Dec. 2, 1942 z sheets-shet 2 lwcntor l HARK y G. muss (lttorncg Patented Jan. 4, 1944 CENTRIFUGAL CASTING APPARATUS Harry G. Yaruss, Brooklyn, N. Y., assignor to .1. F. Jelenko & Co. Inc., New York, N. Y., a cor-7 l poration of New York Application December 2, 1942', Serial No. 467,589

9 Claims.

This invention relates to centrifugal casting apparatus of the type intended primarily for use in dental, jewelry or similar arts or, more generally, for use in casting comparatively small articles or small parts of various articles.

The primary object of the present invention is the provision of a centrifugal casting apparatusv having a furnace heated by a gaseous or other fuel burner in such manner that the interior of the crucible positioned in the furnace is out of communication with the flame of the burner or the combustion products thereof, whereby to prevent any impairment of the metal which is melted in the crucible preliminary to the casting thereof. Heretofore, when gases were utilized for melting metal in the crucible 'of a centrifugal casting apparatus, the heating flame, for example the flame of a blow pipe or the like, was applied to said metal in the crucible, with undesirable results, at least in most cases, because of the oxidizing or,other harmful effect of the flame on the metal. This objection and disadvantage are eliminated by the present invention.

Another object of the invention is to provide a centrifugal casting apparatus having a furnace in which steel and steel alloys can be melted preliminary to the, casting thereof.

The above and other objects, featuresand advantages of the invention will be more fully understood from the following description, considered in connection with the accompanying i1- lustrative drawings: y

In' the drawings: Fig. 1 is a side view in elevationand partly in section, of a centrifugal casting apparatus ernbodying the present invention;

Fig. 2 is a sectional view on the line 2-2 of i tor, but which can be any other type of motor,

35 ther detail.

through holes 36 in barv portions 28. Supporting arms 22 are provided with integral extensions 38 which project below bar I6. A contact carrying block is removably secured between arm extensions 38 by suitable bolts 42.' i

The outer Wall 24 of furnace I8 is preferably formed of sheet metal and is cylindrical. One end of said cylindrical wall is provided with a peripheral flange 44.,to which the rear wall 46 of the furnace is secured in any suitable way, for example by being welded thereto. A front metal wall 48 provided with a central opening 50 is secured to the opposite end of cylindrical wall 24 in any suitable way, preferably byfsecuring the peripheral flange 52 of said front wall to the adjacent edge of the cylindrical wall, for example by screws 54.

A cylindrical refractory muille 56, preferably of alundum, is positioned internally of the furnace and forms the inner peripheral wall of the heaty ing chamber. The opposite ends of the cylindrical muiiie 56 are embedded in 'the end refractory walls 58 and 60 which form the opposite end walls of the heating chamber, said end walls also being preferably formed of alundum. l'I'he peripheral wall'of the 'frace is provided on its -inner surface with a refractory lining Wall 62 which is spaced radially from the'outer surface is mounted for actuating the rotary shaft I4. A

horizontal bar I6, hereinafter to be more specifically described, is removably. secured to the upper end of shaft I4 to rotate therewith. vThe furnace I8 is releasably secured to bar I6 at a point between shaft I4 or the axis of rotation of bar I6 and one end of said bar. The support for furnace I8 comprises a pair of arms 20 and a pair of arms 22 secured at their upper ends to the outer casing 24 of the furnace by screws 26. The lower ends l,

of supporting arms 20 are secured to the laterally spaced parts 28 of b'ar I6 by bolts 30 projected through holes 32 formed in bar portions v26. The lower end portions of arms 22 are similarly'secured to bar portions 2l by bolts 34 passing of cylindrical muille 56 forming an annularv space 59 between said muille 56 and said lining 62. 'The top of the furnace is provided with an -outlet opening 64 for the products of combustion, and the bottom of said furnace is provided with an opening 66 in which a fuel burner"68 is removably positioned as will hereinafter be described in fur- The muiile 56 hasan inwardly projecting portion 10 within which a thermocouple `'I2 ispositioned, Asaid thermocouple being connected by suitable Wiring 13 to the terminal contacts 14 on contact block 40. A movable contact holder 16 is mounted on base I0 and carries contact members 18, which engage the contact members on said block when said holder is projected outwardly. Contacts 18 are connected tc a pyromeyter (not shown)` for indicating the temperature- Awithin the crucible 80. Holder 16 is mounted for sliding movement on base I0 from a retracted position in which said holder is out of engagement with block 40 and the contacts carried by said block to a projected position in which said holder engages said block and the holder` carried contacts engage thejbl'ck carried contacts.` It

will be understood that when holder 16 is moved outwardly so that the contacts 18 engage .con-

, tacts 14, rotation of bar I6 and of the parts carried thereby isprevented and that upon completion of the heatingoperation, as indicated by the pyrometer, the movement of holder 18 inwardly to disengage the same from block 40 allows rotation of bar I6 by motor I2 ,through shaft I4.

Crucible is of cylindrical shape and ilts retion.

movablywithin` the heating chamber of the furnace, and more particularly within muflle 55. Crucible 80 is preferably formed of carbon. Said 1 crucible has a rear wall 82 terminating in a sprue 84 which projects through an opening 86 in rear Wall 46 of the furnace. The front .wall 80 of the crucible is .provided with an inlet opening 90 through which the metal to bemelted can be placed in the crucible. The furnace is provided with an insulated door 92 pivoted to front wall 48 as indicated at 94 and provided at its lower end with a catch 06 which releasably engages a spring projected latch 98 carried by bar I6 whereby to prevent accidental opening of said door.

The burner 68 which is utilized, in accordance with the present invention, for heating the munie 56 for applying heat to the metal within crucible 80 will now be more particularly described. Said burner comprises a chamber supplied with the gaseous or other fluids through valve-controlled supply pipes |02 and |04. For example,

illuminating gas may be supplied through pipe,

|02 and air under pressure may be supplied through pipe |04, when a temperature of about i-2300 F. is required, or other gases may be supplied through said pipes |02 and |04 when higher temperatures are desired. For example, oxygen and acetylene may be supplied to chamber |00 through pipes |02 and |04, respectively, or hydrogen and acetylene may be supplied through said pipes, respectively, when the required heating temperature is about 3800* -F. Chamber |00 is provided with a plurality of branches |06 pref- '.erably of arcuate form (Fig. 2), said branches being of'arcuate form to conform to the cylindrical contour of mufile 56. Said branches |06 carry the burner nozzles |08 for directing the llames of said burner nozzles against the outer Y surface of muflie 56. It will be understoodthat the products of combustion pass upwardly through the annular space 59 around muilie 56 tion of the heating operation as indicated by the pyrometer connected to the thermocouple 12, burner 68 isremoved in order to permit rotation of bar IE and of the parts carried thereby during the casting operation. As here shown, burner 58 is mounted for vertical adjustment on a standard or othersuitable support or base 60. It will be understood that the supply ofiuel and air or other gases to the burner can be controlled automatically by the pyrometer in a manner which is well known and need not -be described as it does not per se form part of the present inven- Referring now in operative position within thefurnace and to be removed from the furnace to-allow rotation of bar I6 and of said furnace during the casting operation, In orderl to provide bar Il with said laterally spaced portions 28, said bar is formed' longitudinally of the bar. An adjustable counterweight ||4 is mounted on bar I6 and is adjustable longitudinally of the latter. Said counter- `nweight is provided with an upwardly extending handle llffor the Vpurpose of facilitating the windingof the spring motor I2 between operai more particularly to bar I0, it -will be noted that the laterally spaced portions 28 of said bar permit the burner 58 to be-inserted and out of the furnace through outlet opening 64. It will be understood that upon the completions of the casting apparatus. A flask holder ||8 is slidably mounted on bar `I6 for movement to adjusted positions toward and away from the outlet opening of the furnace, a clamping screw |20 operable by a handle |22 being provided for releasably clamping the holder ||8 in adjusted position. A flask or mold |24 is mounted between the furnace and the flask holder |I8 and is supported on a cradle |26 which is slidably mounted on bar I6. Cradle |26 supports mold |24 at the proper height in position to be engaged by the flask holder ||8 which holds the forward end of said mold |24 against the outer surface of rear wall 46, with the sprue opening of the crucible in registry with the opening of the mold.

In using the apparatus of the present invention, the spring motor is first wound up by grasp- `ing handle ||6 and rotating bar I0, the contact- VVmaking electrical connection between contacts 14 and 18 of the thermocouple to the pyrometer. The metal to be melted in the furnace is then placed in the crucible and the door 82 is closed. Burner 68 is then placed in ,position for heating the furnace. Then, after the operation of the burner for a suitable lengt-hof time, so that the metal in the cruciblefis melted and the proper temperature is reached, as indicated by the pyrometer which is connected to the thermocouple as indicated above, the bumer is removed and holder 1S is retracted, thereby releasing bar I6 for rotation. Preferably, just before the metal is heated to the desired temperature, the mold is' clamped in position in the apparatus. It will be understood that when Aholder 15 isretracted, bar I6 and the furnace `I8 carried thereby are rotated by spring motor I2, and that the centrifugal force thereby generated causes the molten metal to flow from the crucible through sprue 84 intothe mold |24. y

It will vbe noted that during the'heating of the molten metal in crucible Il, the heating flames are out 'of contact with the metal in tne crucible and that the interior of said crucible is out of communication with the productsof combustion, whereby the metal in the crucible is unimpaired bythe flame of the burner or by the products of combustion. Crucible 0I is preferably formed oi' carbon. as stated above, for

avoiding or counteracting oxidizing action on the metal within the crucible during the melting operation. It will when the metal to carbon thereto, the crucible will be formed of a suitable refractory material, which. will not materially alter-,the composition of the particular type of steel or an alloy thereof. Any refractory material heretofore used in melting steel or its alloys can be used, many of such materials being well known to those skilled in the art. Further, it-will be understood that the crucible is preferably formed ofl carbon when it is desired to add carbon to the steel or steel alloy whichis melted in the crucible preliminary to the centrifugal casting thereof.

It will be understood that various changes may be made in the'casting apparatus embodying the be understood, however, that be melted in the crucible is steel or a steel alloy and it is not desired to add A present invention, and it will be understood also that the burner may be of a different Construction than that illustrated.\ Accordingly, in view of the fact thati various changes may be made without departing from the underlying idea of the present invention, I do not wish to be limited to the construction herein specifically shown or described except to the extent which may be required by the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. In a4 centrifugal casting machine having a furnace adapted to be heated by a fuel burner, said furnace having an outer peripheral wall, a muille positioned within said outer Wall, means supporting said furnace at one side of a vertical axis for rotation about said axis in the casting operation, means releasably engaging a part of said furnace for holding the latter stationary, said furnace having an openingthrough which `said fuel burner may be removably projected for applying heat to said muflle externally thereof while said furnace is stationary, and means for rotating said furnace when said holding meansv is disengaged from said part of the furnace.

2. In a centrifugal casting machine having a furnace adapted to be heated by a fuel burner,

said furnace'having an outer peripheral wall, a muflle positioned within said outer wall, means supporting said furnace at one side of a vertical axis for rotation about said axis inthe Casting operation, means releasably engaging a part of said furnace for holding the latter stationary, said furnace and said supporting means having registering openings through which said fuel burner may be removably projected for applying heat to said muilie externally thereof while said furnace is stationary, and means for rotating said furnace when said holding means is disengaged from said part of the furnace.

3. In a centrifugal casting machine having a furnace adapted'to be heated by a fuel burner, said furnace having an outer peripheral wall, a

l mullie positioned within said outer wall, means supporting said furnace at one side of a vertical axis for rotation about said axis in the casting operation, means releasably engaging a part of said furnace for holding the latter stationary, said furnace having a bottom opening through which said fuel burner may be removably projected for applying heat to said muffle externally thereof while said 4furnace is stationary, and a top opening for the escape of 'the products of combustion, and means for rotating said furnace when said holding means is disengaged from said part of the furnace.

4. In a centrifugal casting machine having a furnace adapted to be heated by a fuel burner, said furnace having an outer peripheral wall, a mufile positioned within said outer wall, means supporting said furnace at one side of a vertical -axis for rotation about said 'axis in the casting operation, means releasably-engaging a part of said furnace for holding the said furnace having an opening through wlnch said fuel burner may be removably projected for applying heat to said muifle externally thereof while said furnace is Stationary, and a Crucible in said muille heated thereby, said mullle being peripherally continuous and imperforate and completely surrounding said Crucible for preventing access of the flame or products of combustion of the burner to the interior of the crucible.

5. In a centrifugal casting machine having e.

furnace adapted to be latter stationary,

heated by a fuel burner,4

axis for rotation about said axis in the castingoperation, said muffle being heated externally by said burner, and a Crucible in said muille heated thereby, said mule being peripherally continuous and imperforate and completely surrounding said crucible for preventing access of the flame or products of combustion of the burner to the interior of the Crucible.

6. -In a centrifugal Casting machine having Va furnace adapted to be heated by a fuel burner and supported at one side of a vertical axis for rotation about said axis in the casting operation, a muiile in said furnace adapted to be heated eX- ternally thereof by the fuel burner While the furnace is stationary, and a Crucible in said muille heated thereby, said mule being. peripherally continuous and imperforate and completely surrounding said Crucible for preventing access of the flame or products of combustion of the burner to the interior of the Crucible.

7. In a centrifugal casting machine having a furnace adapted to be lheated by a fuel burner, a bar mounted for rotation about a vertical axis. said bar having laterally spaced portions, said furnace being mounted on said bar in position over said laterally spaced portions and having a bottom opening in registry with the space between said laterally spaced portions of the bar, and a 'muflle in said furnace in position to be heated by said fuel burner, said spaced bar portions permitting the burner to be removablyy positioned in heating relation to said mule when said bar and the furnace mounted thereon are said laterally spaced portions of the bar, and a v muflle in said furnace in position to be heated by said fuel burner, said spaced bar portions permitting the burner to be removably positioned in heating relation to said muille when said bar and the furnace mounted thereon are stationary and a Crucible in said mufe heated thereby, said mulile being peripherally continuous and imperforate and completely surrounding said Crucible for preventing access of the flame or products of combustion of the burner to the interior of the Crucible.

9. In a centrifugal casting machine having a. horizontal bar mounted for rotation about a vertical axis, a furnace carried by said bar at one side of said axis and rotatable with said bar about asid axis, a muflle having a continuous peripheral Wall disposed in said furnace, said furnace having a wall spaced radially from the outer surface of said peripheral wall providing a space for the passage of hot products of combustion in heat exchange relation with said Wall of the muiiie, said furnace having an outlet for said products of Combustion, and a crucible in said muile heated thereby, said mullle being peripherally continuous and imperforate and completely surrounding said Crucible for preventing access-of the flame or products of combustion of the burner to the interior of the Crucible.

HARRY G. YARUSS.

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