US3064166A - Clamps - Google Patents

Description

Nov. 13, 1962 A. G. E. ROBIETTE 3,064,166

CLAMPS Filed June 5, 1959 4 Sheets-Sheet 1 FIGI.

INVENTOR AL'F'RED G. E. RoBiETTE Nov. 13, 1962 A. G. E. ROBIETTE 3,064,166

CLAMPS Filed June 5, 1959 4 Sheets-Sheet 2 INVENTOR ALT-"RED e. E. ROBI'ETTE A19 ks.

Nov. 13, 1962 A. G. E. ROBIETTE 3,064,166

CLAMPS Filed June 5, 1959 4 Sheets-Sheet 3 INVENT ALFRED Q E. R BI'ETT NOV. 1962 A. G. E. ROBIETTE 3,064,166

CLAMPS Filed June 5, 1959 4 Sheets-Sheet 4 IN VENTOR ALFRED G, E. ROBI'E'I'TE 57 ZMQJM Filed dune 5, 19%, Ser. No. 818,443 1% tjiaims. (til. 317-463) This invention has reference to clamps for supporting furnace electrodes of the continuous, self-baking type, that is to say electrodes of the type comprising a cylindrical sheet-steel casing or shell into which a carbon paste is fed, rammed down and subsequently baked hard by the heat generated within the furnace.

When a furnace provided with electrodes of the said type is in operation, it is known practice to grip each electrode in a clamp through which electric current is also supplied to the electrodes, and to raise and lower the clamp and electrode automatically by a winch, hydraulic cylinder or equivalent means actuated in response to variations in current values so as to maintain a substantially constant liberation of power within the furnace. Further, since the lower and operative end of each electrode is consumed gradually during normal furnace operation, it is customary, for the purpose of compensating for such consumption and ensuring the lower electrode end or tip may, at all times, be capable of being lowered to a predetermined minimum distance from the furnace hearth, to extend the electrode periodically by welding an additional cylindrical section to the upper end of the shell and ramming more carbon paste into the previously existing shell, whereupon the electrode is allowed to slip downwardly within the clamp and/ or the clamp is moved upwardly along the electrode, in a controlled manner; to enable such controlled relative movement between the clamp and electrode to be a steel strip on to the drum of a winch mounted above the electrode and, as each additional section is welded to the upper end of the electrode shell, to weld the said strip to and along the external surface. of the section: hence, as and when the clamp is releaesd preparatory to carrying out the said relative movement, the electrode is supported from the winch by the strip so that either the electrode may be lowered by turning the drum to unwind the strip and/or the clamp be raised upwardly along the shell.

The principal object of the present invention is to provide an improved clamp for supporting a continuous, selfbaking furnace electrode, which is capable of being actuated quickly and easily from a remote position so a to grip and release the electrode as and when desired, the clamp preferably being separate, from and independent of the means for supplying electric current to the electrode thereby avoiding any necessity to vary the contact between the said means and the electrode to permit relative movement.

A further object of the invention is to enable relative movement to take place between the clamp and electrode in a simple, effective and controlled manner.

Still another object of the invention is to minimize the possibility of the clamp or electrode being worn or otherwise damaged as a consequence of such relative movement.

The above and other embodiments of the invention will be clear from the following specification when read in conjunction with the accompanying drawings which show two alternative embodiments of the invention.

In the said drawings:

FIGURE 1 is an elevation showing the upper end of a continuous self-baking furnace electrode gripped within a clamp.

FIGURE 2 is a section,

on an enlarged scale, along the line II-II, FIGURE 1.

- Q 9 carried out, it 18 known to wind 3,954,156 Patented Nov. 13, race w IQ FIGURE 3 is a section along the line III-III, FIG- URE 2.

FIGURE 4 is an elevation, simiiar to FIGURE 1, showing the electrode gripped within a modified or alternative clamp.

FIGURE 5 is a section, on an enlarged scale, along the line VV, FIGURE 4, and

IGURE 6 is a section along the line VIVI, FIG- URE 5.

In the said drawings, 1 is the upper end of the cylindrical shell of a continuous self-baking furnace electrode which, when the furnace is in operation, is adapted to be gripped by a clamp 2 supported upon an apertured platform 3 so that longitudinal movement of the electrode relatively to the platform is prevented. The platform is carried upon the rams 4 of hydraulic cylinders which, under the control of any known and suitable mechanism, are adapted to raise and lower the platform and the gripped electrode automatically in response to variations in the values of the electric current supplied to the electrode so as to maintain a substantially constant liberation of power within the furnace. However, it is to be understood that the said cylinders may be replaced by any other suitable means which is capable of raising and lowering the platform for this purpose. Preferably, a ring or equivalent device (not shown) disposed around and making frictional contact with the external surface of the electrode shell, is adapted to supply current to the electrode and is so suspended from the underside of the platform that it moves with the said platform as and when the latter is raised or lowered.

The clamp 2 shown in FIGURES 1-3, comprises two annular and superimposed groups 5 and 6 of electro-magnets which groups are located around the exterior of the shell 1 above the level of the baked carbon paste rammed into the interior of the said shell. The lower magnet group 5 is supported upon the platform 3 around an aperture through which the shell passes and the upper magnet group 6 is so supported upon the lower group by rams 7 of a system of pneumatic or hydraulic cylinders 3, such tllilai the two groups are spaced apart lengthwise of the 5 ct.

Each magnet comprises eight (or any other desired number) U-shaped yokes or pole pieces 9 which are pitched at equi-angular distances apart around the electrode and of which the arms embrace a single annular coil enclosed in a non-magnetic metal casing 2th disposed around, and substantially concentrically to, the exterior of the shell. The bases of the pole pieces extend vertically across the external periphery of the coil casing and their arms extend horizontally above and below the said casing towards the shell. The pole pieces of the lower magnet group seat and are adapted to slide upon the platform, a corresponding one of the cylinders 8 is mounted upon each pole piece of the said lower group, and each pole piece of the upper magnet group seats and is adapted to slide upon the ram 7 of a corresponding one of the said cylinders.

The pole pieces of the lower magnet group are surrounded by one of three rings 11 which are carried in concentric relationship to the electrode shell, by standard 12 fixed upon and perpendicularly to the platform, the pole pieces of the upper magnet group being surrounded by the other two rings 11; the internal diameter of the said rings is such that each pole piece is free to make a limited floating movement towards and away from the electrode shell so that the pole pieces of the said groups are adapted to move into and out of contact with the shell. The limited floating is preferably of minimum dimension so as to reduce the air gap that may be created between any one of the pole piece faces and the shell surface; if

3 so desired, the movement may be negligible so that the said faces do not actually move out of contact with the said surface when the magnets are de-energized.

If desired, the shell-contacting faces of the arms of the several pole pieces may be coated with a material (not shown), such as rubber, a thermosetting plastic or an asbestos compound, having a high co-efiicient of friction so as to minimize any tendency for the electrode to slip downwardly under its own weight when gripped within the clamp. In addition, the external surface of the electrode shell may be roughened by shot blasting or otherwise, for the same purpose.

As shown in FIGURES 2 and 3, two annular groups 13, 14 of magnetisable segments or keeper plates 15 are suspended by rods 16 within the interior of the shell; the plates of each group alternate with inwardly-projecting radial fins 1a provided on and extending along theinternal surface of the shell to key the carbon paste which is rammed into the shell, the group 13 is disposed in transverse alignment with the lower magnet group 5, and the group 14 is disposed in transverse alignment with the upper magnet group 6. The rods 16 depend from an annulus 17 of a yoke 18 having radial arms 19 which are socketed on to and are supported by the upper ends of pillars 20 fixed upon and perpendicularly to the platform 3.

The upper end of each rod projects through and beyond corresponding holes in the annulus and is formed with a peripheral groove or throat which is engaged by a washer 21 having a radial slot of a width sufiicient to permit passage of the'throat into the eye of the washer, the washer eye being of a diameter which is equal to the width of the slot but less than the diameter of the rod sov that when the throat is disposed within the eye, the head of the rod seats upon and is supported by the washer. To prevent inadvertent disengagement of the washers from their respective rods, the rod heads are received in concentric pockets in the upper surfaces of the washers.

The lower end of each of the rods passes freely through a corresponding one of the keeper plates in each of the groups 13 and 14, the plate in the lower grOup 13 being seatedupon the supported by a nut or washer 22 carried by the rod, and the corresponding plate in the upper group being seated upon and supported by a coil spring 23 disposed around the rod between the two plates (see FIGURE 3).

If desired, the faces of the keeper plates 15 may also be coated with a material, such as rubber or an asbestos compound, having a high co-efficient of friction.

Each of the coils in the casings is so wound that when connected across a source of direct current supply, magnetic poles of opposite polarity are induced at the shell contacting faces of the two arms of each of the pole pieces in the corresponding magnet group. Consequently, upon closing the coil circuit, the pole pieces of the said group and the keeper plates of the plate group which is in transverse alignment therewith, are attracted magnetically into contact with the external and internal surfaces respectively of the shell 1 so that the latter is gripped securely but with minimum possibility'of distortion irrespectively of the gauge of the sheet steel from which it is constructed, between the pole pieces and keeper plates and is held against relative longitudinal movement in the clamp. Normally, when the furnace is in operation either or both of the coil circuits may be closed so that the clamp and electrode are raised and lowered with the platform as the latter is displaced by the rams 4,

However, when it is necessary to lower the electrode within the clamp to compensate for consumption of the lower end or tip of the electrode, the coil of the upper magnet group is energized, the coil of the lower magnet group is wholly or partially de-energized, and the rams 7 are retracted inwardly of their respective cylinders 8. Since the combined weight of the electrode and the upper magnet and keeper plate groups is sufficient to compress the coil springs 23, the total or partial de-energization of the lower magnet group and the retraction of the rams 7, enables the electrode to slip downwardly between the said lower group and the keeper plate group 13 in a controlled manner through any desired distance not exceeding a maximum which brings the upper group of magnets into abutment with the cylinders 8. Having lowered the electrode, the coil of the lower magnet group is energized, the coil of the upper magnet group is de-energized and the rams 7 are projected from their respective cylinders to raise the upper magnet group relatively to the electrode to its initial spaced relationship to the lower magnet group; as the upper magnet group is raised, the springs 23 expand to restore the initial spaced relationship between the upper and lower groups of keeper plates.

As and when it is necessary to extend the electrode shell, the hook 24 of a hoist (not shown) is attached to the crown of a bridge 25 projecting upwardly from the yoke annulus 17, the washers 21 are disengaged from the throats of their respective rods 16, whereupon the hook is raised to lift the yoke from engagement with the pillars 20. The removal of the yoke permits an additional cylindrical shell section to be lowered downwardly of and around the rods until, the lower edge of the said section abuts the upper edge of the shell 1, whereupon the abutting edges are welded together to unite the section to the shell. The yoke may be lowered into r e-engagement with the pillars, the washers may be re-engaged with the rod throats, and the hook 214 may be disengaged from the bridge 25, before or after more carbon paste is fed into and rammed down within the extended shell.

Since the grip exerted on the electrode shell by the clamp is determined by the intensity of the magntic field, induced in the pole pieces by the closing of either or both of the coil circuits and the field intensity may be varied by adjusting the current loads in the said coil or coils, it follows that either or both magnet groups and their respective keeper plate groups may be actuated to grip or release the shell by actuation of control means connected into the coil circuits at any desired remote situation relatively to the clamp. Moreover, since endwise displacement or slip of the electrode shell relatively to either magnet group is permitted by decreasing the intensity of the magnetic field induced in the pole pieces of the group so as to relieve the grip exerted onthe shell by the said pole pieces and their respective keeper plates, it follows that such endwise movement or slip is capable of being controlled closely and accurately and is able to take place with a minimum of wear or damage to the clamp or the shell.

The modified or alternative clamp, shown in FIGURES 4-6, comprises a single annular group of electro magnets 26 which is disposed around and externally of the electrode shell 1, and a single group of rod-suspended keeper plates 27 disposed around and internally of the shell in transverse alignment with the magnet group.

Each magnet is of the box type, has a shell-contacting face which is curved transversely to conform to the external contour of the shell, and houses a corresponding coil'28 which is adapted to energize the magnet when connected to a source of electric current supply. The coil circuits of the several magnets are connected in electrical parallel so that if, for any reason, any one of the magnets develops a fault, the clamp is not rendered inoperative, the grip exerted on the shell by the clamp may be varied by adjusting the current load in each coil individually and independently of the load on the other coils, and any one magnet may be dismantled from the clamp and replaced by afresh magnet without interfering with the function of the remaining magnets.

Each magnet is floatably supported on the platform by a corresponding pair of links 2h disposed on opposite sides of the magnet, each link being pivotally connected by its opposite ends to the magnet and a corresponding cantilever arm 30 which extends over the top of the magnet towards the electrode from the top of one of the upstanding arms of a corresponding U-shaped standard 31 of which the base is fixed upon a carrier ring 32; the carrler ring is secured upon and parallel to the upper surface of the platform by an interposed ring 33 composed of rubber or other electrical insulating material. The floating movement of the magnet towards and away from the electrode, is limited by a bridge piece 34 which is fixed to and between the arms of the corresponding standard 31.

If desired, the shell-contacting faces of the magnets may be coated with a material having a high coefficient of friction; also, the bridges may be so located as to prevent severence of contact between the said faces and the shell surfaces and may consist of electrical vibrators.

The keeper plates 27 are suspended from an overhead annulus by rods 16 and alternate with the longitudinal fins 1a provided upon the internal shell surface so that the shell-contacting faces, which are also curved trans- Versely to conform to the internal contour of the said shell, tend to remain in contact with the said internal surface when the magnets are de-energized. If desired, the number of keeper plates may be any whole multiple or sub-multiple of the number of electro-magnets so that one or more plates is or are associated with each electro magnet or each plate is associated with two or more of the magnets, and the said curved faces may be coated with friction material.

Normally, when the furnace is in operation, the coil circuits of all the magnets are closed and a current of the same maximum predetermined value is supplied to each coil so that a magnetic field of corresponding maximum density is induced and the shell is gripped securely between the magnets and the keeper plates so that the platform, clamp and electrode move in unison as the platform is lifted and lowered in response to variations in the values of the current supplied to the electrode.

However, to enable the electrode to be lowered Within the clamp as and when it is necessary to compensate for consumption of the lower electrode end or tip, any known and suitable means are provided in each coil circuit whereby, when the said circuit is closed, the current load in the circuit, and therefore the density of the magnetic field produced by the group of electro-magnets, may be reduced to any desired value between the maximum and a predetermined minimum so as to vary the grip exerted upon the shell by the corresponding magnet and its associated keeper plate or plates. The reduction in current load to permit the lowering of the electrode in the clamp, may be made in all the coils simultaneously; preferably however, the reduction is made in certain of the coils only whilst maintaining the maximum load in the remaining coils so that a greater degree of control of the electrode movement is obtained.

Also, means may be provided whereby, when he controlled downwards movement of the electrode in the clamp is permitted as a consequence of a reduction in the current load in all or certain of the coils, the initial current load is reinstated automatically in each of the coils after the electrode has moved through a predetermined distance downwardly of the clamp. For example, the clamp may be provided with one or more wheels (not shown) which make rolling contact with the electrode shell so that it is, or they are, rotated as the electrode moves, the or each wheel being adapted, after rotating through a selected one of a range of different angles, to actuate a relay whereby the initial current load is restored.

FIGURE 4 also shows a modified or alternative mechanism for suspending the rods 16. This mechanism comprises an annular yoke 35 having a number of sleeves 36 equal to the number of rods, on and pitched equidistantly apart around, its external periphery, a lesser number of radially projecting lugs 37 each of which is located between two corresponding sleeves, and a substantially inverted U-shaped and upwardly extending bridge 38. The

upper end of a separate one of the rods 16 is secured within each of the sleeves and the lower end of a rod 3Q is detachably connected to the crown of the bridge; the upper end of the rod 39' passes freely through and is supported on a cross bar 40 which is fixed to and between the upper ends of the pillars 20.

In radial alignment with each of the lugs 37, a corresponding pneumatic or hydraulic cylinder 41 is pivoted upon the internal periphery of a ring 42 secured to the pillars 29 at a lower level than that of the said lugs. The outer end of the piston rod of each cylinder is coupled to a corresponding pawl 4-3 which is pivoted on and projects upwardly from a small diameter ring 44 secured to the underside of and in concentric relationship, to, the pillar-supported ring 42.

Except when it is desired to extend the electrode shell by welding an additional section to its upper edge, the piston rods are retracted inwardly of their respective cylinders 41 and the rods 16 and yoke 35 are suspended from the cross bar 40 by the rod 39. To enable the electrode shell to be extended the piston rods are projected so as to take the noses of the pawls 43 into engagement with the undersides of their respective lugs and the rod 39 is disconnected from the bridge 38 and removed from the cross bar 40 by, for example, the hook of a hoist, the yoke thus being supported by the pawls. Due to the removal of the rod 39, the lower end of a cylindrical shell section may be passed over the bridge and located temporarily around the yoke, whereupon the rod 39' is reconnected to the bridge, the cylinders 41 are actuated to disengage the pawls from their respective lugs, and the section i lowered downwardly of the yoke and plate suspension rods 16 into abutment with the upper edge of the existing shell preparatory to being welded to the latter.

it is to be understood that the embodiments of the invention described above and shown in the drawings are only typical examples of how the invention should be carried into effect and that various modifications may be made within the scope of the following claims.

I claim:

1. A clamp for a furnace electrode of the kind comprising a cylindrical shell, the said clamp comprising at least one annular system of electro magnets disposed around and externally of the shell and supported upon a platform through which the shell extends, means for disposing the platform relatively to and longitudinally of the shell, pillars projecting from the platform beyond one end of the shell, a carrier supported on the said pillars in spaced relationship to the said shell end, an annular system of rods connected to and depending from the said carrier through the said shell end into the shell interior, and at least one annular system of keeper plates mounted upon the said rods within the shell and in transverse alignment with the said magnet system, the rods being so connected to the carrier that the said keeper plates are free to float towards and away from the internal surface of the shell.

2. Apparatus for holding and adjustably feeding a furnace electrode comprising an electrode formed of metal and of tubular shape, a plurality of electromagnets disposed around and externally of the electrode, and a plurality of floating keeper plates disposed around and internally of the electrode and constructed and arranged to grip the electrode between the magnets and keeper plates upon ener ization of the magnets.

3. Apparatus for holding and adiustably feeding a furnace electrode comprising a cylindrical metal shell forming said electrode, a plurality of electromagnets disposed around and externally of the shell, and a plurality of keeper plates disposed around and internally of the shell, each of the said magnets including a floating pole piece and each of said keeper plates being fioatably supported within the shell, whereby upon energization of the magnets the pole pieces and keeper plates are attracted towards one nace electrode comprising a cylindrical a another into abutment with the shell and the shell is gripped between the magnet and plate systems.

4. Apparatus according to claim 3 in which each keeper plate is located in transverse radial alignment with a corresponding one of the electromagnets.

5. Apparatus according to claim 3 wherein said electrode shell is positioned substantially vertically and contains rammed carbon paste in the lower part thereof, the said magnets and keeper plates being disposed above the level of the carbon paste.

6. Apparatus according to claim 3 wherein said plurality of electromagnets include a single, annular, current conducting coil concentric to and surrounding the shell, and each of said pole pieces is of U-shape and embraces the coil with its arms extending towards the external shell surface.

7. Apparatus according to claim 3 wherein each of the said floating pole pieces encloses a corresponding current conducting coil.

8. Apparatus for holding and adjustably feeding a furmetal shell forming said electrode, two systems of electromagnets disposed around and externally of the shell and spaced apart lengthwise of the shell, means disposed between the magnet systems for varying the distance by which the said systems are spaced apart, and a corresponding system of floating keeper plates disposed around and internally of the shell in respective transverse alignment with each of the said magnet systems whereby upon energization of the magnets in either magnet system the keeper plates of the corresponding keeper plate system are attracted into contact with the shell and the latter is gripped between the magnets and plates of the said corresponding systems.

9. Apparatus for adjustably holding and feeding a furnace electrode comprising a cylindrical metal shell forming said electrode, a carrier located in spaced relationship to one end of the shell, a plurality of rods projecting through and beyond the same end of the shell with their projecting ends connected to said carrier, at least one annular system of electromagnets disposed around and ex-' ternally of the shell, and at least one annular system of keeper plates disposed around an internally of the shell in transverse alignment with the said magnet system, each of said keeper plates being carried by a corresponding one of said rods and being free to float towards and away from the internal shell surface.

10. A clamp for a furnace electrode according to claim 1 comprising further a second annular system of electromagnets positioned externally of the shell and spaced longitudinally of the shell from said first system, means for changing the said spacing systems of magnets, a second system of keeper plates inside the shell for cooperation with said second system of magnets and means for energizing said first and second systems of magnets individually.

References Cited in the file'of this patent UNITED STATES PATENTS 1.862,120 Northrup June 7, 1932 2,100,537 Chalker Nov. 30, 1937 2,453,488 Bowen Nov. 9, 1948 2,564,850 MacChesney Aug. 21, 1951 2,668,183 Foyn Feb. 2, 1954' 2,778,865 Kongsgaarden Jan. 22, 1957 between said first and second

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