US2484865A - Electric furnace workpiece ejector mechanism - Google Patents

Description

Oct. 18, 1949. H. A. sTRlcKLAND, JR

ELECTRIC FURNACE WORKPIECE EJECTOR MECHANISM Filed Jan. 10, 1946 HAROLD AST-RICKLAND, JR

. A TTORNE Y Patented Oct. 18, 1949 ELECTRIC FURNACE WORKPIECE EJECTOR MECHANISM Harold A. Strickland, Jr., Detroit, Mich., assigner, jby mesne assignments, to The Ohio Crankshaft Company, Cleveland, Chio, a corporation of Ohio Application January 10, 1946, Serial No. 640,229V

5 Claims.

This invention relates to ejector equipment, having particular utility as'applied to induction furnace chambers. y

Ininduction furnaces the heating chamber is usually formed by a Acylindrical coil dening a tubular interior within which the workpiece is positioned for heating through inductive action. The inlet or mouth end of the furnace is at one end of the coil o-fsuch a furnace the other end may be open for insertion of mechanism as desired. Insertion of the workpiece is usually by manual means through the mouth-piece, the same being placed fully within bothends of the coil so that the inductive action may be uniform. In this position theworkpiece may not be easily grasped for removal by tongs or the like applied at the inlet end.

One of the primary'objects of the present invention is to provide ejector mechanism which by simple mechanical manipulation may be made to force out the heated workpiece from the heating chamber of the furnace to a point where the operator by means of tongs or other devices may readily grasp the same and remove it bodily from the chamber. Another object of the invention is to provide such a push-out mechanism as may be readily utilized in conjunction with tubular work-pieces, for example, shells. Still another object is to provide a push-out device usable in connection with tubular work-pieces which in its structure tends to prevent substantial heating therein resulting in injury to the device and improper and undesired absorption of energy. An object also is to provide a push-out device which lends itself without any mani-pulation to a disruption of current flow in its structure during the period of heating by the furnace, but which automatically when subjected to pressure in the push out operation adjusts itself to a plural contact upon theworkpiece, thus facilitating easy removal of the `workpiece and properly balancing the `load on the push-out device. An object of importance in conjunction with the apparatus also is the employment of magnetic units inl order to divert the liux flow from the push-out device and thus aid in preventing undue heating thereof. An associated object is the provision of iiux diverting means which is not only protective to the push-out device itself, but also aids in modifying the heating effect along the workpiece as desired. Another object related to the use of the mechanism is the employment of means for protecting the support of the push-outl device so that `even though the support may be contained `in part within `the furnace interior end,

2 walls, the action of the inductiondoes notfunduly overheat the same bringing about a malformation of the Vsupporting structure when subjected to load impact while in aA heated condition. Other objects of theinvention will be apparent on consideration of a form ofthe invention which may be preferred hereinafter described and .i1- lustrated in theaccompanying drawing-,-in which:

Figure 1 is a side elevation partly in sectionof a portion of a furnace illustrating the placement and mode of operation of the push-out mechanism;

Figure 2 is a section through the push-out rod and support taken alonglines 2-2 `of Figure 1, illustrating the split support tube andthe `mode of application of the T-bar to the workpiece; and

Figure 3 is.anenlargedfragmentary sectional View showing the push-out mechanism of Figure 1 in greater detail.

In my copending application SerialNo. 384,503, filed March 2l, 1941, Electric furnace machine, now Patent No. 2,408,350, issued September 24, 1946, I have illustrated and describedmechanism of the general type herein-disclosed butapplicable primarily to a solid rod or bar positioned as a load within an induction coil. While the structure of this prior application is useful under certain conditions of use, .there is a tendency for the rod end of the push-out device to become overheated and to flare outwardly due to impact of the load when being pushed into position. Also, the supporting tube or stock-gauge, as it is called, is also liable to overheatingand as a resulttends to mushroom through load impact thus destroying thel usefulness of the device. 'Ihe structure of the herein described mechanism tends to overcome these deficiencies by preventing undue development of eddy currents in the push-rod end, and also yby slotting the end of the support tube diminishes the eddy current flow in the supporting tube itself.

Referring to Figure l of the drawing, there is disclosed a section of an induction furnace including a support plate I to the ends of which is attached a casing having a front face 3 and a rear face 4. The front face of the casing is apertured to receive a mouthpiece plate 5. This mouthpiece is centrally apertured and provided with inwardly extending fingers 6 which are spaced from each other and converge to define an inlet opening for the guidance of workpeces into the chamber of the furnace. The induction coil unit of thefurnace'is set up in `prolongation of the mouthpiece opening, being shown as mounted upon I-bars T and 8 resting on the base I and adjustably secured by C-clamps 9 and III which in turn rest on the I-bars l and 8. The C-clamps are provided with adjustable devices II and I2 which are preferably yieldable so that a firm grip of these holding devices-there being three provided--is secured.

The induction heating unit itself is a coil of tubular conductor I5 preferably rectangular in cross-section, insulated on its outer surface by heat-resistant material such as Transite and on its inside by insulating tubing I6 andan inner layer of firebrick I1. Embedded in the rebrick as a cylindrical grill is a plurality of hollow tubes or rails axially extending and provided with load bearing plates I8 for supporting the load I9, which in the present instance is a pipe or shell. This grill is fixedly secured in direct alignment with the inlet opening of the mouthpiece 5 so that when the workpiece is inserted through the mouthpiece it enters the heating chamber of the coil and may be pushed completely therein.

The push-out mechanism generally indicated by the numeral is placed adjacent the end of the heating unit opposite from the mouthpiece, that is, on the rear side of the furnace. The mechanism includes a supporting bracket 2I bolted to the rear casing plate and adapted to receive adjustably the push-out rod support 22. This support is tubular and movable for adjustment not only in the bracket 2|, but through an aperture formed in the casing plate, so that from a point exterior to the casing the support tubing may be axially adjusted. Alternatively, this support is frequently referred to as a stock-gauge in that it gauges the extent of inner movement of the stock or workpiece inside the furnace. Inasmuch as the stock-gauge has a limiting function for the workpiece, it is preferably slotted for a short distance at the furnace end, as indicated by the numeral 23, for a purpose hereinafter to be described.

The push-out rod 24 is slidably movable in the direction of its axis within the support tube 22. This rod is of extended length and is provided adjacent its outer end outside of the casing with an adjustable collar 25. Supported also on the rear casing are brackets 26 and 21, one above the other, the bracket supporting a hydraulic motor 28 having a movable piston 29 adapted to have pivotal attachment at its end to a lever arm 30 pivoted at 3| for movement thereof. The lever arm 30 is xedly connected to a second lever arm 32 which at its free end is engageable with the collar 25 on the push-out rod so that when uid pressure is exerted within the motor bringing about outward movement of the reciprocatable member 29, the pivoted lever 383--32 rotates on the pivot 3| `to cause movement of the collar 25 and attached rod 24 toward the furnace. A spring 33 tends to return the extensible member 29 of the motor, as well as the arm 32 0f the lever, to inoperative position, permitting unrestrained outward movement of the push-out rod 24. Hydraulic pressure is applied to the motor-through the tubing 34 as controlled by the valve 35 which may be either adjacent the casing or at a point displaced therefrom as, for example, in front of the casing where it may be easily accessible to the operator.

The inner end of the push-out rod 24, that is, the end movable into the furnace chamber, is fitted with a cross bar which preferably is transverse to the rod. The function of this cross bar is to engage at its ends the end of the tubing, such as a shell. which may constitute the workpiece of the furnace so that when the push-out rod is manipulated to move inwardly from the rear, by such engagement the shell is moved outwardly to a point where it may be completely removed by the operator. It is pointed out that this cross bar, while it extends on either side of the push-out rod to points adjacent the shell end, makes contact only at point 4I in the normal heating position of the workpiece, whereas at the point 42 there is a physical disconnection between the cross bar end and the shell end. The purpose of this construction is to insure that during the heating operation there is no short circuiting of the metal constituting the cross bar and shell resulting in an undue heating of the bar with deleterious effects. However, it is also desirable that during the actual push-out of the workpiece there should be contact on opposite sides of the shell in order to insure balanced pressure against the workpiece. This is accomplished by the structure as shown, utilizing for the cross bar metal of such dimensions and substance that the yield under pressure permits contact at the top as well as the bottom of the bar. The degree of yield need be but small since the only requirement as regards the gap at the point of disconnection at the top of the bar, as shown in Figure 1, is that there be no actual conduction of current.

There is also provided to add further protection to the cross bar in the prevention of undue heating thereof an accessory unit generally indicated by the numeral 45. This unit consists of a plurality of radially extending laminated plates of usual transformer iron-containing composition. This laminated unit is attached to the push-out rod 24 in any effective manner and serves for the purpose of diverting the flow of flux which normally passes through the shell interior in such a manner that less density of ux develops in the cross bar 40 than would be the case if the unit were absent. This unit is preferably adjustable as to its point of attachment on the push-out rod so that the point of greatest effectiveness may be found at which the unit is permanently held. It is pointed out in connection with this unit that its action in diverting flux may be useful also at displaced points along the interior of the workpiece in that the density of ux in the workpiece itself may be modified and consequently the heating effect. Where it is desired that different degrees of hardness, for example, be imparted to a shell by properly spacing flux-diverting units as that illustrated at 4'5, such a result may be brought about through a diversity in the heating of the shell from point to point. These various units may be all secured to the push-out rod as a convenient means of support.

Summarizing the operation, the workpiece is inserted through the mouthpiece and forced to the rear limit of the furnace chamber engaging the cross bar 40 of the push-out mechanism and moving it to the rear point until it contacts with the stock-gauge 22. At this point the collar 25 of the rear end of the push-out rod is in engagement with the lever arm 32 of the operating mechanism. The heating cycle is commenced and the shell brought up to temperature. During this heating the electromagnetic energy is effective not only on the shell, but on the cross bar 40 as well as upon the end of the stock-gauge 22. However, by reason of the slotted end of the stock-gauge the circuital currents in the stockgauge are effectively diminished, and as regards the cross bar, the contact of the same with the workpiece at only one point is effective in conjunction with the diverting action of the laminated unit 45 to very substantially reduce the heating effect of the magnetic flux. On the completion of the cycle the operator manipulates the valve means 35 bringing about activation of the motor and an inward movementof the push-out rod 24, both ends of the cross bar 40 engaging the workpiece and forcing the same outwardly through the mouthpiece to the point of rod engagement by the operator.

The apparatus as described is preferred, but of course there may be modifications. For example, the motor is described as the hydraulic type; other types maybe used. Also, the apparatus has been specifically related to an induction furnace. However, we believe the apparatus may be successfully applied to the other units wherein it is desired to provide ready means for removal of a tubular load normally subject to magnetic flux. Other modifications may be made such as may come within the scope of the appended claims.

What is claimed is:

1. In electrical furnace equipment, an induction coil having a chamber adapted to receive a generally cylindrical workpiece, a recprocatable rod movable in said chamber in alignment With the workpiece, a workpiece-engageable element forming the chamber end of the rod, and means for reciprocating said rod to shift the workpiece outwardly from said chamber, said element comprising a member with at least two branches extending angularly from said rod engageable with the workpiece for ejection thereof with one branch nominally extending into the chamber beyond the other branch.

2. A push-out rod for tubular workpiece subject to inductive electromagnetic iiux and contained in a tubular furnace, comprising an elongated member, means fcr supporting said member for axial movement into and out of said furnace, plural `workpiece engaging elements xed to the end of the member adjacent the furnace, one only of said elements being normally in metallic electrical conductive relationship with the workpiece during the heating cycle, the other of said elements normally moving into contact with said workpiece on the application of pressure on the member to force the workpiece out of said chamber.

3. A push-out rod mechanism for tubular workpieces subject to magnetic iiux and contained in a tubular electric induction furnace, comprising a push-out rod, means for supporting said rod for axial movement into and out of said furnace, a

workpiece engaging member fixed to Said rod for p engagement ywith the workpiece, means for moving the rod and member toward said workpiece, and means for reducing the ux density effective in said member during the time of power application to said furnace.

4. A push-out rod mechanism for tubular workpieces subject to magnetic flux and contained in a tubular furnace, comprising a push-out rod, means for supporting said rod for axial movement into and out of said furnace, a workpiece engaging member fixed to said ro-d engageable with said support and workpiece, and separate means for reducing the flux density in said support and said member during the time of power application to said furnace.

5. In an induction furnace, a tubular conductor coil forming a furnace chamber adapted to receive a tubular workpiece, a rod normally positioned along the coil axis, a support for said rod, means for moving the rod axially of the coil, workpiece engaging means secured to the rod for engagement with, and movement of, a tubular workpiece, and means mounted on Said rod for modifying the flux density of the coil effective in said contact means and workpiece.

HAROLD Ai. STRICIUJAND, JR.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,367,124 Colby Feb. 1, 1921 1,862,120 Northrup June 7, 1932 2,182,341 Hulster Dec. 5, 1939 2,257,580 Trompeter Sept. 30, 1941 2,337,258 Limpel Dec. 21, 1943 2,363,724 Ford Nov. 28, 1944 2,371,066 Richter Mar. 6, 1945 FOREIGN PATENTS Number Country Date 583,460 France Oct. 31, 1924

Images