US3327276A - Current collector head - Google Patents

Description

T. MASSEY, JR, ET L 3, 6

7 June 20, 1967 CURRENT COLLECTOR HEAD 3 Sheets-Sheet J Filed June 29, 1964 INVENTORS 777o/7 ms Masse m .5 E h 3 Rd June 20, 1967 MASSEY, JR ET AL 3,327,276

CURRENT COLLECTOR HEAD Filed June 29, 1964 3 Sheets-Sheet 2 INVENTORS 7710mm; Massey Jr. Roy E. IVI'C/7 o/s /o/m E. 620/72 June 20, 1967 -r MASSEY, JR" ET AL 3,327,276

CURRENT COLLECTOR HEAD 3 Sheets-Sheet 5 Filed June 29, 1964 INVENTORS 7770/7746 Massey J): Ray E. Niche/s United States Patent 3,327,276 CENT COLLECTOR HEAD Thomas Massey, Jr., Ray E. Nichols, and John E. Swift, Baltimore, Md., assignors, by mesne assignments, to Bethlehem Steel Corporation, a corporation of Delaware Filed June 29, 1964, Ser. No. 378,538 1 Claim. (Cl. 339-5) This invention relates to a collector head assembly, and more particularly to an assembly adapted for use in the continuous electrolyzing of metal strip.

In one commonly adopted form of electroplating metal strip, as, for example, tin electroplating of steel strip, the strip is passed horizontally across a bath of electrolyte solution containing an electrode connected to a source of electric current. A rotatable contact roll engages the moving strip, and is connected to the source of electric current to complete the electric circuit through a portion of the strip.

Normally, the strip passes the contact roll at the exit end of the plating cell, the common practice being that of passing the strip between two rolls, with a metal, usually steel, contact roll at the top, and a backing roll, covered with some non-conductive substance such as rubber, bearing on the strip immediately below the contact roll, the center lines of the two rolls being in vertical alignment.

The contact rolls, which are generally made in the form of a hollow cylinder, may vary in diameter, depending on the type of operation, from possibly 3 inches to 15 inches or more. In a modern, high speed tinplating line of the horizontal type, the roll will have a diameter of about inches, and a width sufficient to take care of a 42 inch wide strip. Each end of the roll has a reduced diameter portion to form a journal which fits a journal bearing. A portion of the reduced diameter section of the roll extends beyond the journal bearing, and this extended portion is fitted with a copper sleeve, which acts as a collector ring on which carbon brushes are in slidable electrical contact.

In the operation of a high speed tinplating line, there are times when a condition known as tin-pickup develops on the contact rolls. Tin becomes transferred from the coated strip to the metal roll, and in time increases to such magnitude that an unsatisfactory contact exists between the roll and the moving strip, resulting in an ineflicient operation. Tin-pickup may be removed from the roll during the plating operation by an abrasive operation known as stoning, but this operation, if continued for long periods, may cause a camber in the roll, and require that the roll be removed, from the line and reconditioned.

As it is desirable that the contact roll move at all times in an even plane, in relation to the strip and backing roll, the journal bearing in which the roll rides is made to a relatively close tolerance which in turn, leads, at times, to galling between the journal and bearing. Generally, when galling becomes severe, the only solution to the problem is to stop the line, remove the roll and replace it, after restoring the bearing to an operable condition.

Formerly, in conducting the current from the collector ring of the contact roll, via brushes to the collector head, brushes have been arrayed around the entire periphery of the collector ring, the brushes being held in fixed position against the collector ring, and being physically attached to a copper distributing plate and steel backing plate, which formed part of the collector head.

With this type of collector head it was necessary, whenever a contact roll was removed from the line, to remove the collector head or brush holder arms also. As it is normally the practice to use brushes on each end of the roll, this meant a double removal operation. In removing a collector head, and restoring it to an operative position 3,327,276 Patented June 20, 1967 after a roll has been replaced, brushes and brush holder arms are frequently damaged, requiring further repair, delay or expense during a roll change.

An object of the present invention, therefore, is to produce a collector head assembly for contacting a contact roll, wherein the roll can be removed from its position in an electrolytic cell, without removing the collector head.

Another object is to provide a collector head which has a retractable brush assembly, to permit a simple and positive current disconnecting means.

A further object is to provide a collector head assembly, wherein the brushes are not exposed to damage upon removal or replacement of a conductor roll.

An additionalobject is to provide a simple method for retracting groups of brushes to minimize wear, when full capacity is not required.

With these objects in mind, we have developed an improved collector head assembly, which provides for the rapid removal and replacement of the contact roll, and which, at the same time, minimizes the possibility of damage to any part of the collector head during the roll changing operation.

In the drawings:

FIG. 1 is an end view of the collector head assembly, with brushes in engagement with the contact roll.

FIG. 2 is an end view of the collector head assembly, with brushes disengaged from the contact roll.

FIG. 3 is a top view, taken substantially along the line 33 of FIG. 1, showing one set of brushes in engaged position.

FIG. 4 is a top view, taken substantially along the line 33 of FIG. 1, showing one set of brushes in disengaged position.

FIG. 5 is a front elevation of the complete assembly, partly in section, with one set of lower brushes in engaged position, taken substantially along the line 5-5 of FIG. 1.

FIG. 6 is a view, in some detail, of a single brush, and a portion of a brush holder, with the brush in engaged position, taken along the line 6-6 of FIG. 5.

FIG. 7 is similar to FIG. 6, but with the brush in disengaged position and electrical cables omitted.

In broad outline, salient features of this invention include two fixed yokes, or supporting plates, upon which the assembly depends. The yokes, being open at the top, provide for the free vertical movement of the contact roll, when roll changes are made, Without removal of any part of the collector head assembly. A plurality of brush holders, supported between the yokes, are arranged in spaced relation about the periphery of a collector ring, attached to a lower segment of an extension of the contact roll. This lower segment comprises about percent of the cross-sectional area defined by the periphery of the collector ring. Brushes, attached to the brush holders,

and which make contact with the reduced end portion of the contact roll, are retractable, so that they may be positioned in contact with the roll during normal plating operations, and withdrawn from such contact to permit the necessary roll changes.

The improvement comprising this invention will be readily understood by reference to the drawings. Referring particularly to FIGURES '1 and 5, contact roll 11 has a collector ring, in the form of a copper sleeve 12, which is force fitted to reduced cylindrical contact roll portion 13, and secured by lock-nut 16. Collector ring 12, which carries spiral grooves 62 on its surface, acts as the collector ring for the contact roll. The collector head assembly 10 is positioned around the collector ring 12, as shown in FIG. 1.

In the complete collector head assembly, there are four sets of brush holders 17, 17, 17" and 17". Each brush holder supports six brushes 18. As the upper set of brushes in the facing position has been omitted from FIG. 5, a clearer view of the relationship of each set of brushes to the collector ring can be obtained by reference to FIG. 1. In FIG. 1, the brushes are shown making contact with the collector ring 12. FIG. 2 is substantially the same view as that shown in FIG. 1, but with the brushes retracted, and out of contact with the collector ring.

The entire brush holding assembly of four brush holders is supported between the yokes 14 and 15 by rods 34 as shown in FIG. 5. The yokes are in turn supported on support plate 21, yoke 14 being connected to plate 21 by bolts 22 and 23 through supporting rib 26, with yoke 15 being likewise connected to plate 21 by bolts 24 and 25 through supporting rib 26. Lock nuts 28 and 30 hold bolts 22 and 25 respectively against ribs 26 and 26, while adusting boltheads 27 and 29 can be operated to position ,the collector head assembly in a vertical direction.

A copper distributor plate 31 is secured to yoke 14. The distributor is connected to a bus bar, not shown, and it also makes electrical connection with the brush holder assembly, the current flowing from distributor plate 31, into the brush holder 17 to lugs 32 and through connecting leads, not shown, to brushes 18.

The whole assembly may be covered with a sheet metal lid 19. This lid is merely for the purpose of preventing dirt fro-m falling on the assembly, and can be readily removed by handle 20, when it is necessary to make roll changes, or adjustments to the assembly.

Each set of brush holders is held between the two facing plates, 'or yokes 14 and 15, by a rod 34, extending through each individual brush holder. Rod 34 is attached to yokes 14 and 15 by means of nuts 36 and 36' respectively. A locating pin 37, extending through yoke 14 and distributor plate '31, is centered in an opening in the brush holder at 38. Pin 37 prevents rotary movement of the brush holder.

With each brush holder located between the yokes, in the manner just described, brushes 18, supplied to brush holders 17, 17', 17" and 17", bear against the contact roll collector ring 12 in the manner shown in FIG. 1. The brushes, which are made of a metal graphite composition, are slidably mounted in the copper brush holder, and have a curvilinear contact surface, which conforms with the periphery of the collector ring 12. Copper strip 39, welded to the brush holder, as shown in FIGURES 3 and 4, acts as support for each brush, either in the engaged or disengaged position. Each brush has a slot 40 at the center of its sliding face, to accommodate a corresponding raised portion on the brush holder area upon which the brush moves. The purpose of the slot is to maintain proper alignment of each brush.

To ensure a positive electrical contact between distributor plate 31 and brushes 18, a set of six electrical cables extend from each lug 32 to each brush 18. Electrical cables 41 are shown in FIG. 6. The cable ends are embedded in drilled holes in the end of the brush, and are held in place by a cement containing conductive metal powder.

Referring to FIG. 3, it will be observe-d that each brush 18 carries an insert 42. The insert 42, against which hammer 44 bears, is made of insulating material. The insert is force fitted into a keyway in the brush, and is held there by two dowels 43, as shown in FIG. 6.

Referring again to FIG. 6, a bronze hammer 44 connects with brush 18 through link 45 which in turn operates in slot 46, located in the insert 42 of brush 18. When the brush is in operating position, i.e. in contact with the collector ring 12, the tapered, or bearing, end of hammer 44 bears on insert 42, and holds the brush in electrical contact with the collector ring. The link 45 between hammer and brush is, at this point, in reposed position. To provide sufiicient force in the hammer bearing to hold the brush firmly against the collector ring, when in the operating position, pressure is maintained on the hammer by a high tensile, stainless steel coil spring 61, which is held in place at the pivoted end of the hammer. One end of the spring is restrained against an offset 47 of the brush holder frame. The spring is coiled around a protruding cone-shaped portion 48, which portion is integral with hammer 44 and journaled on rod 49. The other end of the spring, shown at 50, extends beyond the hammer, and is adjacent thereto. To maintain pressure on the hammer, sufficient to hold brush 18 in place, spring end 50 may be placed in locked position in any one of a number of slots 51 arrayed around the offset, curvilinear edge of the upper portion of hammer 44. To retract the brush and pull it away from the collector ring, the hammer is forced away from the brush, in which case link 45 is placed under tension, and operates to hold the brush in the retracted position shown in FIG. 7.

Referring to FIGURES 3 and 6, hammer control bar 52, extending substantially the length of the brush holder, is located adjacent each hammer 44, and is shown out of physical contact with the hammers when the brushes are in electrical contact with the collector ring. When it is desired to retract the brushes, bar 52 is forced against the hammers, pushing the hammers back to a point where the brush is pulled away from the collection ring. This latter position of bar 52 is shown in FIGURES 4 and 7.

The entire control bar assembly, shown in FIGURES 3 and 4, includes the bar 52, and pivoted arms 53 and 54. Arm 53 is pivoted in yoke 15 at 56, and arm 54 is pivoted in yoke 14 and distributor plate 31 at 57. The means, by which arm 54 is pivoted, extends beyond yoke 14 and through locking arm 55 at 58. Extension 58 is in the shape of a round projection, flattened to permit use of a wrench to raise or lower the brushes, and locking arm 55 is in slidable relation therewith. By manually pushing arm 55 along extension 58, in a direction away from yoke 14, arm 55 can be made to operate bar 52, and the free end of the arm can be placed on either side of stop 59, as desired by rotating extension 58 with a suitable wrench. Once the proper position of the arm, in relation to stop 59 is attained, the arm is pushed back along extension 58 in the direction of the distributor plate, and is thus locked in position, with the control bar held either in or out of operating position, as the case may be. Referring once again to FIGURES l and 2, it will be noted that when arm 55 is in a position in which the beveled portion 60 bears. against stop 59, bar 52 is out of contact with hammer 44, and brush 18 is in electrical contact with the contact roll. When the fiat side of arm 55 bears against stop 59, control bar 52 is forcibly held against hammer 44, to the extent that brush 18 is pulled away from, and out of contact with collector ring 12.

It will be obvious from the foregoing description, that changes can be made in the construction of the collector head assembly, without altering the nature or spirit of the invention. For example, the number of brushes in a brush holder unit can be reduced or increased, depending on requirements and adapatability to a given plating line. Then too, the number of brush holder units can be limited to one, two or three, depending on the current load required.

In the example given, each collector head is designed to operate at approximateily 4500 amperes, when either three or four sets of brush holders are placed in operation.

While it is possible to operate with a collector head at one end of the conductor roll only, for the most efficient operation a collector head assembly should be used at each end of the roll.

The invention is not limited to electroplating, but can be applied to any electrolyzing operation, where it is necessary to use a contact roll, which must be periodically removed and reinstalled.

We claim:

A collector device for collecting current from a horizontally disposed rotatable contact roll having a cylindrical end portion bearing a collector ring, comprising a plurality of brush holders disposed in spaced relationship about the periphery of a lower segment of said collector ring, at least one brush slidably mounted in each of said brush holders and connected electrically thereto and a separate hammer connected to each brush by a link and slot arrangement, spring engaging means mounted on each hammer for holding said brushes under proper compression When in slidable electrical contact with said collector ring, a bar movable toward or away from each said hammer and capable of contacting said hammer and locking said hammer and related brush in a retracted position out of contact with said collector ring, one end of each set of brush holders being mounted independently on and in electrical contact with a current distributing plate held by an adjacent supporting plate and the other end being 15 mounted independently on a supporting plate, said distributing plate and said supporting plates having openings sufiicient to permit removal of said collector ring.

References Cited UNITED STATES PATENTS ARTHUR L. LA POINT, Primiary Examiner.

STANLEY T. KRAWCZEWICZ, Examiner.

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