US3747808A

US3747808A - Molten metal pouring device having pantograph tilting mechanism

Info

Publication number: US3747808A
Application number: US00198360A
Authority: US
Inventors: J Richman
Original assignee: Pennwalt Corp
Current assignee: Stokes Vacuum Inc
Priority date: 1971-11-12
Filing date: 1971-11-12
Publication date: 1973-07-24
Anticipated expiration: 1990-07-24

Abstract

A metallurgical casting furnace for pouring one or a plurality of horizontally spaced molds. System utilizes a cradle which is adapted to arcuately position a crucible for pouring while allowing either horizontal or vertical ingot charging. A pantograph tilting mechanism permits the crucible to be retained in upright position during arcuate displacement and is also adapted to tilt the crucible independently for teeming into one mold at a time. Vacuum, air melt or controlled atmosphere environments may be employed.

Description

United States Patent [1 1 Richman MOLTEN METAL POURING DEVICE HAVING PANTOGRAPII TILTING v MECHANISM [75] Inventor: Jay Leivis Richman, Philadelphia,

[73] Assignee: Pennwalt Corporation, Philadelphia,

[22] Filed: Nov. 12, 1971 21 Appl. No.: 198,360

[52] US. Cl. 222/166, 164/136 [51] Int. Cl 822d 37/00 [58] Field of Search 222/165, 166, DIG. 8;

[56] v References Cited UNITED STATES PATENTS 3,393,837 7/1968 Takeshima... 222/166 521,519 6/1894 Adams 222/165 [4 1 July 24, 1973 FOREIGN PATENTS OR- APPLICATIONS 143,082 10/1930 Switzerland 222/166 404,496 Germany 222/166 Primary Examiner-Robert B. Reeves Assistant Examiner-David A. Scherbel Attorney-Stanley Bilker [57] ABSTRACT A metallurgical casting furnace for pouring one or a plurality of horizontally spaced molds. System utilizes a cradle which is adapted to arcuately position a crucible for pouring while allowing either horizontal or vertical ingot charging. A pantograph tilting mechanism permits the crucible to be retained in upright position during arcuate displacement and is also adapted to tilt the crucible independently for teeming into one mold at a time. Vacuum, air melt or controlled atmosphere environments may be employed.

5 Claims, 4 Drawing Figures PATENIEBJULZMSB SHEET 1 0F 2 lwm r .58

M/VENTOR JAY LEW/S R/CHMAN ATTORNEY mmmmz I 3,741. 808

' m: z or 2 INVENTOR JAY LE WIS R/CHMAN ATTORNEY MOLTEN METAL POURING DEVICE HAVING PANTOGRAPH TILTING MECHANISM This invention relates to a metallurgical furnace and more particularly relates to a melting furnace which is adapted to pour and cast one or more molds under vacuum, air or controlled atmosphere environments. The system is especially adaptedv for molds introduced into a vacuum chamber in horizontally spaced disposition with each other.

The present invention concerns a research and development furnace for studies especially directed to vacuum melting and casting of high quality vacuum grade alloys, including the fabrication of directionally soliditied castings. The instant system is semi-continuous in nature and is particularly adapted to a system in which a mold is elevated into a vacuum mold chamber by means of a lift assembly operating within an airlock. After the mold is poured,- provisions may also be made to allow the mold itself to be withdrawn at a controlled rate within a mold heater, if desired, such that crystal growth can be oriented in a predetermined direction.

It is therefore an object of this invention to provide a metallurgical casting furnace in which a furnace crucible may be positioned and tilted in opposite directions in order to serve a plurality of molds.

Another object of this invention is to provide a vacuum melting furnace in which the crucible may be positioned for either vertical, horizontal or angular charging without requiring alterationin the positioning cradle assembly.

Still another object of this invention is to provide a plural casting vacuum melting furnace in which a single cradle is adapted to hold the crucible in upright position during melting and/or charging, and after displacement over the various mold positions permit tilting of the crucible into pouring disposition.

Other objects of this invention are to provide an improved device of the character described that is easily and economically produced which is sturdy in construction and both highly efficient and effective in operation.

With the above and related objects in view, this invention consists of the details of construction and combination of parts as will be more fully understood from the following detailed description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a sectional elevational view of a vacuum melting furnace with plural casting means embodying this invention. 4

FIG. 2 is a sectional view taken along lines 2-2 of FIG. 1.

FIG. 3 is a side elevational view, and partly in section, of another embodiment of the vacuum melting and casting furnace.

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 3.

melting a charge of metal loaded therein. Electrical power and cooling water are supplied to the crucible A. through a flexible conduit 12 which passes through a seal plate 14 mounted on the vacuum chamber B.

The vacuum chamber B includes a steel water jacketed shell 20 which houses the crucible A and a pair of

locks

22 and 24 situated therebelow for loading the molds D into the melt chamber 20 through a flapper valve 26 into a pouring position below the crucible. The furnace or crucible A can be positioned for vertical charging through ingot or slug charging mechanism 28. As an alternative, horizontal ingot charging may be accomplished through slug loading mechanism 30 shown in phantom by the broken lines. The vertical charger 28 (and the horizontal charger 30 option, if employed) is equipped with valved evacuation lines and vacuum break valves (not shown) to permit repeated use while maintaining chamber vacuum. Regardless of whether vertical, horizontal or angular charging is selected, the mechanism is capable of loading ingots 4 inches to 20 inches in length and from 2% inches to 4 inches in diameter.

The valved ingot charger 28 is designed to reliably place the alloy slug on the bottom of the empty crucible A, including the ability to add an ingot to a partially filled crucible containing molten metal. In addition to the charging mechanisms, there is also included a valved port 32 by way of which thermocouple leads (not shown) may be passed for treating melt temperature. The port 32 may also be employed for a bridge breaker assembly, as a means for alloy addition, for observation and as a way of sampling the melt.

The tilting mechanism C includes a rotary positioning shaft 34 which is journaled in

bearings

36 and 38 suspended from the roof of the melt chamber 20. The shaft 34 extends through a rotary seal 40 at one end of the melt chamber 20 and is rotatably actuated by a drive motor-gear-reducer system 42. A pair of spaced support arms 44 and 46 are rigidly affixed to the shaft 34 as by welding.

Trunnions

48 and 50 outwardly extending from the crucible A are rotatably journaled in bearings at the lower ends of the respective support arms 44 and 46. Thus, the crucible A is so mounted that it is free to rotate with respect to the support arms 44 and 46. A sprocket 52 is affixed to trunnion extension 51, and a chain 54 engages sprocket 52 and one side 56 of double sprocket 57 in a closed loop. The other side 58 of double sprocket 57 carries a chain loop 60 which is driven by drive sprocket 62. The hub of double sprocket 57 is free to rotate about support shaft 34. Tilt drive shaft 64 is keyed to drive sprocket 62 and is rotatably journaled in bearing seal 66 mounted in the melt chamber wall 20. Motor drive 68 is adapted to turn shaft 64 upon demand.

For operation during positioning, shaft 34 and support arms 44, 46 are rotated by drive unit 42 so as to arcuately position the crucible, as desired. The tilting mechanisms (sprocket 52, sprocket 57 and sprocket 62 via the chain belts 54 and 60) are held meanwhile in restraint by drive motor 68 and shaft 64 so that the crucible A itself does not rotate. This serves to maintain the crucible A in an upright position to prevent premature tilting whereby controlled conditions for charging, melting, etc., are achieved. That is, the double sprocket 57 rotates freely on support shaft 34 while the latter is turned. Therefore chain 54 is free. to wrap and unwrap about

sprockets

52 and 56 in the manner of a parallelogram of forces or a pantograph. However, after the crucible has been positioned along the arc, the drive 68 may be actuated so as to rotate the crucible out of its upright vertical position into pouring position at I or I or vertical charging position II (or into horizontal charging position as at III). With the foregoing arrangement, the crucible A can be positioned and/or tilted in two diametrically opposed directions to serve two molds.

Referring now to the alternative embodiment of FIGS. 3 and 4, there is shown a modified form C1 of the pantograph positioner in which the pivotal axis of the suspension is located below the level of the crucible A. In the embodiment C1, the crucible A, the vacuum chamber B and the

mold locks

22 and 24 as well as the molds D may be substantially identical to the system shown in FIGS. 1 and 2, or variations may be included without departing from the spirit of this invention. As shown, the

flapper valves

26 and 27 are shown in closed position, valve 27 being also shown in dotted lines to indicate the manner of its being swung into open disposition to permit passage therethrough of the mold D. The melt chamber B is evacuated through port 70 which is connected to a vacuum pump (not shown) through suitable conduit. Mold

heaters

72 and 74 are illustrated and permit the molds D to be heated and cooled under controlled conditions, such as for directional solidification. A mold locker door 76 is depicted in leg 24 to show the means in which the molds D are loaded and unloaded into the melting chamber B. A ram or elevator (not shown) is included within each of the

legs

22 and 24 for raising the molds D into the melt chamber and then retracting the molds at a controlled rate from the mold heaters.

The pantograph positioner and tilt mechanism C1 includes a rocker 78 rotatably supported with respect to an internal journal 80 and outside journal 82. The rocker 78 actually constitutesa sleeve which is coaxially disposed and freely rotatable about tilt shaft 84, the latter being journaled at its right hand end, as shown in FIG. 4, within block 86 while the outside periphery of rocker 78 is joumaled within left hand bearing 82. Rotary motion for the rocker 78 is provided by a sprocket or crank 88 which is connected to a suitable drive actuator (not shown), such as by a chain or piston. Rotary motion for the tilt shaft 84 is furnished by a suitable motor 90. A pair of upstanding arms 91 and 92 are fixedly secured to the rocker 78 and constitute a cradle for the crucible A. Trunnions 94 and 96 out-, wardly extending from the crucible are pivotally supported in respective bearings in the cradle arms 91 and 92. A sprocket 98 secured to the right hand end of trunnion 96 is coupled by way of a chain 100 to sprocket 102 keyed to tilt shaft 84.

As is apparent from the foregoing description in connection with FIGS. 3 and 4, rotation of the crucible A to its desired arcuate position is accomplished by rotation of rocker 78 through drive 88. Since the rocker 78 freely rotates on the now rotatably-fixed shaft 84, the sprocket 98 and chain 100 will follow the arcuate position in the manner of a pantograph such that the cruelble A can remain upright in all positions. In arcuate position IV with the crucible A upright, the crucible can be vertically loaded by slug or ingot charger 104. In order to pour the crucible contents into a mold D, the rocker 78 is arcuately turned until the crucible is located over the corresponding mold D as in position V or V. The crucible A is then tilted so as to pour the molten metal through the open upper aperture in the

mold heater

72 or 74 preparatory to casting.

Through the use of the pantograph positioning system C or C1, the crucible A can be oriented very close to the furnace wall B for charging, thereby reducing the stroke of the charging mechanism and overall height of the furnace. The crucible can be positioned for either vertical or horizontal charging without requiring any change in the basic positioner construction. The centerline of the crucible A always coincides with the centerline of the molds, and this position does not change throughout the positioning arc. It is also apparent that gears may be substituted for the chain and sprocket tilting mechanisms, and other modes of construction may also be employed as well.

Although this invention has been described in considerable detail, such description is intended as being illustrative rather from limiting, since the invention may be variously embodied without departing from the spirit, and the scope of the invention is to be determined as claimed.

What is claimed is:

l. A metallurgical furnace comprising a crucible, trunnions outwardly extending from said crucible, means constituting a rocker rotatably supporting said trunnions, said rocker being pivotally supported about a primary horizontal axis spaced from the axis of said trunnions, first drive means for pivoting said rocker so as to arcuately displace said crucible in a generally orbital path about the primary horizontal axis, endless loop means constituting a pantograph having one portion thereof rotatably supported freely about the primary horizontal axis and a second portion thereof coupled in direct rotatable engagement with said trunnions, and second drive means integrally coupled in direct engagement with said endless loop means for effecting rotation thereof, whereby actuation of said first drive means while said second drive means remains unactuated and stationary will cause arcuate displacement of said crucible without effecting tilting thereof and actuation of said second drive means while said first drive means is retained in unactuated disposition will produce tilting of the crucible in the same plane as the orbital plane of arcuate displacement.

2. The furnace of claim 1 wherein the axis of said trunnions is located below said axis of said rocker, said pantograph comprising a sprocket coaxial and rotatable with one of said trunnions, a second sprocket co-. axial with and freely rotatable about the axis of said rocker, and a chain inter-connecting said first and second sprockets whereby said chain and said second sprocket will rotate freely so as to maintain the crucible upright when said means for pivoting said trunnions is stationary and said means for pivoting said rocker is actuated.

3. The furnace of claim I wherein said rocker constitutes a shaft, a sleeve rotatably supported coaxially about said shaft, means for rotating said sleeve, and means for rotating said shaft.

4. The furnace of claim 1 wherein the axis of said trunnions is located above the axis of said rocker.

5. The furnace of claim 4 wherein said rocker constitutesa shaft, a sleeve rotatably supported coaxially about said shaft, means for rotating said sleeve, means for turning said shaft, a sprocket coaxial with and rotatable with said shaft, a second sprocket coaxial with and rotatable with one of said turnnions, and a chain interconnecting said first and second sprockets.

t! t t t

Claims

2. The furnace of claim 1 wherein the axis of said trunnions is located below said axis of said rocker, said pantograph comprising a sprocket coaxial and rotatable with one of said trunnions, a second sprocket coaxial with and freely rotatable about the axis of said rocker, and a chain inter-connecting said first and second sprockets whereby said chain and said second sprocket will rotate freely so as to maintain the crucible upright when said means for pivoting said trunnions is stationary and said means for pivoting said rocker is actuated.
3. The furnace of claim 1 wherein said rocker constitutes a shaft, a sleeve rotatably supported coaxially about said shaft, means for rotating said sleeve, and means for rotating said shaft.
4. The furnace of claim 1 wherein the axis of said trunnions is located above the axis of said rocker.
5. The furnace of claim 4 wherein said rocker constitutes a shaft, a sleeve rotatably supported coaxially about said shaft, means for rotating said sleeve, means for turning said shaft, a sprocket coaxial with and rotatable with said shaft, a second sprocket coaxial with and rotatable with one of said turnnions, and a chain interconnecting said first and second sprockets.