US3293347A - Electrode stub clamp - Google Patents

Description

Dec. 20, 1966 P. J. WOODING I 3,

ELECTRODE STUB CLAMP Filed Oct. 24, 1965 2 Shee ts-Sheet 1 IIVVEIVTOR PATH/CK J. WOOD/N6 f M f g ATTORNEYS.

Dec. 20, 1966 P. J. WOODING ELECTRODE STUB CLAMP 2 Sheets-Sheet 2 Filed Oct, 24, 1965 F/G. 4 Y

NW BH uwewrok PATR/C'K J. WOOD/1V6 By S z ATTORNEYS.

United States Patent 3,293,347 ELECTRODE STUB CLAMP Patrick J. Wooding, Moorestown, N.J., assignor to Consarc Corporation, Rancocas, N.,l., a corporation of New Jersey Filed Oct. 24, 1965, Ser. No. 504,498 9 Claims. (Cl. 13-14) This application is a continuation-in-part of my copending US. patent application Serial No. 253,220 filed on January 22, 1963, now Patent No. 3,215,974.

In order to develop the ultimate in physical properties, many alloys are consumably remelted after initial production of chemically sound electrodes by conventional air melting or vacuum induction melting techniques. These electrodes may be cast in electrode molds specially designed for the purpose or forged from cast ingots. Consumable remelting is effected by suspending the electrode in a water-cooled mold and melting is progressively accomplished by arc or resistance heating. The melting maybe carried out in a vacuum, under an inert gas blanket, or in air with a layer of slag to protect the are or create a resistance heating path.

Regardless of the means .of producing the electrode, it must be supported in an upright position and so aligned that there can be no danger of arcing or other contact between the electrode and the inner surface of thewatercooled mold. The normal means of suspension is a water-cooledram designed to carry currents of the order of many thousand amperes. For example, a furnace designed to produce a maximum electrode weighing twelve tons would have a ram designed to carry approximately 35,000 amperes.

The present invention relates to a means for releasably connecting the electrode .to the water-cooled, currentcarrying ram. Many different .types of clamping devices have been proposed heretofore. Most of thedevices proposed heretofore require lengthy periods of adjustment and/or are expensive to maintain.

Therequirements of .a clamp'or connecting means for this purpose are thatit should be effective .over a wide range of electrode weights; it should be capable of carrying the furnacemaximum rated current; it should connect and disconnect virtually instantaneously without the use of heavy wrenches orother tools; it should lock the .electrode on the upright axis of the furnace and prevent swinging of the electrode due to electromagnetic or other forces at the lower end of the electrode; the locking and disconnecting actions should be positive; it should include provision for welding sections of electrodes together in the furnace or related equipment by applying pressure in a downward direction. without danger of electrode misalignment; it should have arelatively low initialcost; and it should have very low or minimum maintenance cost due to replacement of wearing parts.

In my co-pending application Serial No. 253,220, now Patent No. 3,215,974, referred to hereinbefore, one solution of the. problem involved was set forth. The solution set forth therein utilized two sets of gripping ball members which were adapted to cooperate with the outer surface of the electrode stub. One set of ball members was utilized to retain the electrode stub while the second .set of ball members was utilized to prevent the electrode from swinging under the influence ofthe electromagnetic forces involved.

The clamp of the present invention also overcomes the deficiencies of prior clamping devices. The stubs which cooperate with the clamp of the present invention may be reused indefinitely and may be welded directly to the electrodes while supported by the clamp of the present invention. Therefore, machining and replacement costs of stubs are very small relative to pounds of metal produced per stub.

It is an object of the present invention to provide a novel clamp adapted to be releasably engageable with an electrode stub.

It is another object of ,the present-invention to provide an electrode stub clamp which is simple, capable of being connected or disconnected with a minimum of effort, and which prevents swinging of an electrode due to an electromagnetic force at the lower end of the electrode.

It isanother object of the present invention to provide a novel electrode stub clamp adapted to support an electrode in an upright position.

It is another object ofthe present invention to provide an electrode stub clamp which has a relatively low initial cost and little maintenance cost due to replacement of ,shown in the drawings a form which is presently .pre-

ferred; it being understood, however, that this-invention is not limited to the precise arrangements and instrumentalities shown.

FIGURE 1 is a sectional view of the clamp of the present invention prior to engagement with the stub of an electrode.

FIGURE 2 is a sectional view of the clamp of .the present invention illustrating a relationship between the parts of the clamp and the stub during the connecting action.

FIGURE 3 is .a sectional view of the clamp of the present invention showing the relationship between the elements of the clamp and the stub when the stub is locked to the clamp.

FIGURE 4 is a partial sectional view of the present invention illustrating the relationship of .the elements .upon the electrode.

FIGURE 8 isa perspective view of the sleeve within which the pressure pins are mounted.

Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown an electrode stub clamp, designated generally .as 10.

The clamp 10 is suspended at the lowermost end of a wa ter-cooled, current-carrying ram-12. The clamp 10 includes an. annular housing 14 made from a copper alloy or otherv good current carrying material. The housing 14 is generally cylindrical and is provided with a guard,16 made from a lightweightstainless steel or other suitable material. The ram 12 is threaded at its lower portion 13 thereof and is threadingly connected to the uppermost end 18 of the housing 14.

'The end of the housing 14 remote from the. uppermost end 18 is provided with an axial aperture 20. A cage 22 extends through the aperture 20 into the housing 14 and is reciprocally guided .by the aperturel t). The cage Patented Dec. 20, 1966 clearly shown in FIGURES 1 and 3.

22 may be made from a material such as mild steel and is in the nature of a cylindrical sleeve. Cage 22 is provided with a radially inwardly directed lip 23 at its uppermost end. At its lowermost end, cage 22 is provided with a radially outwardly directed extension 24. The steel guard 16 is connected to the extension 24 by means of screws 17. Washers 19 are provided between the connection of the steel guard to the extension 24 of the cage 22 to prevent electrical and thermal heat conduction between the housing 14 and the steel guard 16. The screws 17 are also composed of a material which will substantially prevent electrical and thermal heat conduction.

The inner surface of the housing 14 is provided with two axially extending portions 26 and 27 which function as guides for reciprocating the cage 22. Hereinafter the surfaces 26 and 27 may be referred to as axially extending walls. Thus, it is readily apparent that the cage 22 is guided for reciprocation by aperture 20 and axially extending walls 26 and 27, all of which are axially spaced along the axis of the housing 14.

The inner surface of the housing 14 at the lowermost end thereof is irregularly shaped. Commencing beyond the axially extending wall 27 is an arcuate surface 28 merging into a tapered surface 30 which converges towards the aperture 20. The tapered surface 30 merges into an axially extending surface 32 which merges into a further tapered surface 40 which converges towards the ram 12. The tapered surface 40 merges into a radially extending surface 41 which merges into the axially extending wall 26.

The cage 22 is provided with a row of holes 36. A plurality of spherical balls 38 are supported in the space between the outer surface of the cage 22 and the inner surface of the housing 14 below the radially extending surface 41. Eight balls are provided in the illustrated embodiment, however a greater or lesser number may be provided if desired. The balls 38 are preferably made from a good electrically conductive material which may be identical with the material of the housing 14. The balls 38 are adapted to project through the holes 36 as will be made clear hereinafter.

A plurality of aligned bores on an inclined axis are provided in the housing 14 for receiving a latch member 46. Latch member 46 may be provided with outwardly projecting opposing pins 48 which are adapted to cooperate with a stationary member 49 having slots therein for receiving the pins 48. The latch member 46 is biased toward the upper end portion of cage 22 by spring 50. In FIGURES 1 through 3, the pins 48 engage the outer peripheral surface of the member 49, thereby overcoming the bias of spring 50 and retaining the latch member 46 in an inoperative position. The cage 22 is provided with a peripheral groove 42 which cooperates with the latch member 46 in a manner to be described hereinafter.

Three pressure pins 52, which may be made out of stainless steel or other suitable material, extend through holes 53 provided in the uppermost end 18 of housing 14.

Each pin 52 is provided with a ceramic ball 54 at the lowermost end thereof. The three pins 52 are equally spaced around the housing 14 as readily seen in FIGURE 5. The pins 52 move vertically Within mutilated sleeves 56 which are fixedly positioned in the housing 14. The sleeves 56 are provided with arcuate edges 58, as clearly shown in FIGURE 8, for a purpose which will be described hereinafter. The sleeve 56 adjacent latch member 46 is also provided with an opening 60 which permits passage of the latch member 46 therethrough.

The pressure pins 52 can be locked in their lowermost positions by means of locking drifts 62. The locking drifts 62 are generally rectangular in shape and are made of rectangular bar stock which is generally commercially available. The drifts 62 are positioned so that their diagonals are substantially horizontal and vertical as The lowermost corner of each of the drifts is partially removed to form a sloping bevel 63 (see FIGURE 7). Each drift 62 has an opening 66 therein through bevel 63 which is large enough to permit passage of the pins 52 therethrough.

Each drift is mounted in a sleeve 64. Each sleeve 64 is preferably composed of round bar stock and has a rectangular inner periphery. Such bar stock is readily commercially available. Each sleeve 64 has an opening 65 therein which is substantially the same size as, and adapted to be aligned with, the opening 66 in the drifts 62. Each drift 62 is provided with limit stops 68 which limit the horizontal movement of the drift 62 within the sleeve 64. For purposes of convenience, the position wherein the openings 66 of the drifts 62 are aligned with the openings 65 in the sleeves 64 and the pins 52 will be referred to as the inoperative position of the drifts. Conversely, the position wherein the openings 66 are not aligned with the openings 65 and the pins 52, will be referred to as the operative position of the drifts 62. The limit stops 68 cooperate with housing 14 to limit the extent of movement of the drifts 62 between operative and inoperative positions.

The clamp 10 is adapted to be releasably engaged with a stub 70. Stub 70 is provided with an end face 74 and a beveled surface 72 extending between the surface 74 and the outer peripheral surface of the stub. The stub 70 is formed with a reduced diameter portion 76 at the uppermost end thereof. A peripheral groove 78 is spaced from the portion 76 by a normal diameter portion 80 of the stub 70. The portion 80 has a radially inwardly extending edge 81 at the uppermost portion thereof which is formed due to the difference in diameter between the portion 76 and the portion 80. The distance between the groove 78 and the end face 74 is slightly less than the distance between the end face 74 and the row of holes 36 as clearly shown in FIGURE 2.

The end of the stub 70 remote from the face 74 is adapted to be welded to one end of an electrode (not shown) and substantially concentric therewith. For purposes of illustration, one embodiment of the present invention utilizes a stub 70 having a diameter of approximately seven inches and a length of approximately twelve inches. The stub 70 is adapted to be utilized with an electrode having a diameter of up to twenty-six inches. The stub 70 is preferably made of steel.

The clamp of the present invention is utilized as follows:

A stub 70, possibly already welded to one end of an electrode, is positioned below the clamp pin and aligned approximately on the same axis as the ram 12. The ram 12 and the clamp pin are then lowered over thestub 70. The taper of surface 72 guides the stub into the cage 22. When the surface 74 on stub 70 contacts the ring of balls 38, further downward movement of the cage 22 is prevented until the housing 14 has moved down a suflicient distance to permit the balls 38 to roll up the tapered surface 30.

The ram 12 and housing 14 continue to descend until the extensions 24 of the cage 22 come into contact with the bottom of the housing 14. This relationship may be readily ascertained by means of a scribe line on the stub 70 or by the position of the upper edge of the steel guard with respect to a reference mark on a housing 14. During the descent of the ram 12 and the housing 14, the drifts 62 are in inoperative position thus allowing the pins 52 to move upwardly from a position substantially as shown in FIGURE 1 to a position substantially as shown in FIGURE 2. Accordingly, the operating mechanism for the ram 12 is reversed, thereby causing the ram 12 to move upwardly. At this point, it should be noted that the groove 78 is above the ring of balls 38, see FIGURE 2. As the ram 12 and housing 14 move upwardly, the balls 38 roll down the tapered surface 30 onto the arcuate surface 28 wherein they project through the holes 36 into the groove 78. Hence, the stub 70 sleeves 56 should be readily apparent.

and the electrode attached thereto will now move up wardly with the clamp 10.

The reason for the arcuate edges 58 on the mutilated The arcuate edges 58 on the sleeves 56 allow the cage 22 and the stub 70 to move upwardly without being impeded by the sleeves 56. Thus, each sleeve 56 effectively functions as a sleeve and also does not protrude into the path of any moving parts.

At this point, the pressure pins 52 will have moved downwardly through the sleeve 56 into engagement with the beveled surface 72 of the stub 70. In order to lock the pins 52 into positive engagement with the surface 72 the drifts 62 are moved from their inoperative to their operative position. One of the limit stops 68 cooperates with the housing 14 to define the inoperative position of the drift 62. In order to move the drift 62 to its opera tive position it need only be moved horizontally to move the other limit stop 68 toward engagement with the housing 14. In actual practice, this is accomplished by merely hitting the drift 62 with a hammer in the direction of movement desired. After the drifts 62 are moved into their operative position, the pressure pins 52 will be locked in engagement with the beveled surface 72 of the stub 70.

Such engagement prevents the electrode which is fixedly -of the electrode and stub 70 to be supported frombelow.

At or slightly before this point, the drifts 62 will be moved from their operative position to inoperative position. Thereafter, the ram 12 will be lowered downwardly until the cage extensions 24 are seated against the bottom of the housing 14. In this position, the groove 42 of the cage 22 is in alignment with the latch member 46. In moving the ram downwardly, the balls 38 will be caused to roll up the tapered surface 30 and thereby be no longer in contact with the stub 70. At this point, the latch member 46 will be moved inwardly. In the illustrated embodiment this will be accomplished by rotating the latch until the opposed pins 48 align with the slots in the stationary member 49 as illustrated in FIGURE 4, thereby enabling the springs 50 to move the latch member inwardly into groove 42. Thus, the latch 46 will lock the cage 22 in a fixed vertical position. The cage 22 may still be rotated about its axis.

During the lowering of the ram 12, the pressure pins 52 have been permitted to move upwardly through the openings 66 in the drifts 62, since the drifts are in their inoperative position.

At this point, the cage 22 is positively held in position by the latch member 46 cooperating with the groove 42. The ram 12 is now raised in an upward direction. As the ram 12 moves upwardly, there is no relative movement between the housing 14 and the cage 22. Since the balls 38 will not project through their holes, continued upward movement of the ram 12 results in a separation between the clamp and the stub 70 and the electrode carried thereby on its supporting surface.

The advantages of the present invention include positive locking and unlocking features which are virtually automatic. The clamp exerts high radial pressure on the electrode stub in proportion to the mass of the electrode thereby permitting transfer of the melting currents involved which are also roughly proportional to the mass of the electrode. The clamp 10 components are simple and relatively loosely fitting and, therefore, by proper selection of materials, the clamp 10 is capable of withstanding temperature of several hundred degrees Fahrenheit during the melting operation. Also, the steel guard 16 is connected to the cage 22 and serves to protect the clamp from radiant heat and metal splatter and also gives external visual indication of the position of the cage inside the clamp. The visual indication of the position of the cage inside the clamp is obtained by providing a vertical index groove on the upper surface of the guard 16 which may be aligned with any one of various numbered graduations equally spaced on the exterior of the annular housing 14. In order to minimize wear of the various elements, it has been found desirable to rotate the cage after each use of the clamp which is accomplished by utilizing the index groove on the guard member 16 and the graduations equally spaced on the exterior of the housing 14. The pressure pins 52 which cooperate with the drifts 62 prevent automatic disconnection of the clamp 10 with respect to the stub 70 except when desired. Also, by

utilizing the sloping beveled bottoms 63 of the drifts 62 to cam the pins 52 downwardly when the drifts 62 are moved to operative position, the pins 52 permit downward pressure to be exerted on the electrode stub 70, without misalignment, for Welding purposes.

The wearing parts of the clamp 10 are the balls 38. The 'balls 38 are preferably made of a tough current carrying copper alloy. After the wear on the balls 38 has become excessive, it is necessary to replace them. This is achieved by raising the cage 22 upwardly until the extensions 24 come into engagement with the bottom of the housing 14. In this position the latch member 46 is aligned with the groove 42 of the cage 22. The latch member 46 is moved inwardly to engage the groove 42 and lock the cage in a fixed vertical position. At this point, the guard 16 is removed by simply disengaging screws 17 from the extension 24 of the cage 22. This permits ready access to the threaded plug 39. After the plug 39 has been removed the balls may be replaced individually by rotating the cage 22 until the ball to be replaced is in line with the plug opening. Thus, the balls can be replaced in a simple, quick, and efficient operation.

It will be appreciated that the stub 70 may be interconnected with the clamp 10 as described above and then welded to one end of an electrode by passing current through the ram 12, clamp 10 and stub 70, thereby striking an are between the lowermost end of the stub and the juxtaposed end face of the electrode. When an electrode has been consumed, only a small plate-like portion will remain integral with the stub 70. The plate-like portion will then be separated from the stub 70 by a cutting torch or the like. Thereafter, the stub 70 will be welded to a new electrode and reused in the same manner described above.

The present invention may be embodied in other specific forms Without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims rather than to the foregoing specification as indicating the scope of the invention.

I claim:

1. Apparatus comprising a hollow body open at one end, a perforated cage disposed in said hollow body, said hollow body being reciprocably disposed with respect to said cage, movable members in said body, means for moving said movable members for partially projecting them into said cage, said cage being rotatable in said body about its longitudinal axis, latch means for retaining said cage in a definite position with respect to said body while permitting the cage to rotate about said longitudinal axis so that relative reciprocable movement between said body and said cage is prevented, a current carrying means connected to the other end of said body, said body and said members being made from a material which is a good electrical conductor.

2. Apparatus comprising a hollow body open at one end, a perforated cage disposed in said hollow body, said hollow body being reciprocably disposed with respect to said cage, movable members in said body, camming means for moving said movable members between an operative and inoperative position, movable means adapted to contact an electrode stub, a drift element supported by said body movable between a locking and an open position, said drift element cooperating with said movable means to permit movement of said movable means when said drift element is in open position, said drift element and said movable means cooperating with said movable members when said movable members are in operative position to lock said hollow body to an electrode stub and prevent relative reciprocal movement between the electrode stub and said body, and means for connecting an electrical conductor to the other end of said body.

3. The apparatus as set forth in claim 2 wherein a shield partially surrounds said body, and said body and said members being made from a material which is a good electrical conductor.

4. The apparatus as set forth in claim 2 wherein a guard is connected to the lowermost end of said cage for shielding said body.

5. The apparatus as set forth in claim 2 wherein a latch is provided for locking the cage in a predetermined position while permitting the cage to rotate about its axis so that relative reciprocable movement between the body and said cage is prevented.

6. Apparatus as set forth in claim 2 wherein a radial bore is provided in said body through which said movable members may be replaced.

7. The apparatus as set forth in claim 2 wherein said drift element has an opening therein, said movable means includes at least one vertically movable pressure pin, said pressure pin aligned to be received by the opening in said drift element when said drift element is in open position, said drift element being horizontally movable to move said opening out of alignment with said pin to a position wherein said drift element is in locking position to thereby lock said pin in a substantially fixed vertical position.

8. Apparatus as set forth in claim 7 wherein said drift element has a sloping bevel for camming said pin into its locked vertical position.

9. Apparatus comprising a hollow housing open at one end, a cage having spaced openings therein disposed in said hollow housing, said cage reciprocably disposed with respect to said housing, movable members in said housing, means for moving said movable members so that they ipartially project into the spaced openings in said cage, at east one drift element supported by said housing for movement between a locking position and an open position, an opening in said drift element, at least one movable pressure pin, said pressure pin being aligned to be received by the opening in said drift element when said drift element is in open position, said drift element being movable to move said opening out of alignment with said pressure pin to a position wherein said drift element locks said pressure pin in a definite position, said drift element and said pressure pin being adapted to cooperate with said movable members to lock an electrode stub to said housing when said drift element is in a locking position, a guard connected to the bottom of said cage for shielding said housing, a latch for locking the cage in a predetermined position while permitting the cage to rotate about its axis to prevent relative reciprocal movement between said housing and said cage, means for connecting a current carrying conductor to the other end of said housing, said housing and said movable members being made from a material which is a good electrical conductor.

References Cited by the Examiner UNITED STATES PATENTS 685,677 10/1901 Furbish 285-277 1,031,637 7/1912 Fischer 2853l5 1,997,649 4/ 1935 Ohlund 287 2,126,674 8/1938 Stout 33975 2,394,236 2/1946 Eastman 285277 2,429,202 10/ 1947 Estill et al 285277 2,969,410 1/1961 Darngen et al 339241 X 3,032,359 1/1962 Cator 285-277 3,046,319 7/1962 Daley 1314 3,215,974 11/1965 Wooding 13-l6 X JOSEPH V. TRUHE, Primary Examiner.

Claims (1)

1. A APPARATUS COMPRISING A HOLLOW BODY OPEN AT ONE END, A PERFORATED CAGE DISPOSED IN SAID HOLLOW BODY, SAID HOLLOW BODY BENG RECIPROCABLY DISPOSED WITH RESPECT TO SAID CAGE, MOVABLE MEMBERS IN SAID BODY, MEANS FOR MOVING SAID MOVABLE MEMBERS FOR PARTIALLY PROJECTING THEM INTO SAID CAGE, SAID CAGE BEING ROTATABLE IN SAID BODY ABOUT ITS LONGITUDINAL AXIS, LATCH MEANS FOR RETAINING SAID CAGE IN A DEFINITE POSITION WITH RESPECT TO SAID BODY WHILE PERMITTING THE CAGE TO ROTATE ABOUT SAID LONGITUDINAL AXIS SO THAT RELATIVE RECIPROCABLE MOVEMENT BETWEEN SAID BODY AND SAID CAGE IS PREVENTED, A CURRENT CARRYING MEANS CONNECTED TO THE OTHER END OF SAID BODY, SAID BODY AND SAID MEMBERS BEING MADE FROM A MATERIAL WHICH IS A GOOD ELECTRICAL CONDUCTOR.

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