US2576074A - Method and apparatus for continuous strip metal treatment - Google Patents

Description

Nov. 20, 1951 J. s. NACHTMAN 2,575,074

METHOD AND APPARATUS FOR CONTINUOUS STRIP METAL TREATMENT Original Filed Feb. 18, 1959 s Sheets-Sheet 1 INVENTOR FigJA.

Nov. 20, 1951 r J. s. NACHTMAN 2,576,074

METHOD AND APPARATUS FOR CONTINUOUS STRIP METAL TREATMENT Original' Filed Feb. 18, 1939 i s Sheets-Sheet 2 INVENTOR Nov. 20, 1951 J; 5. NACHTMAN 2,576,074

METHOD AND APPARATUS FOR CONTINUOUS STRIP METAL TREATMENT Original Filed Feb. 18, 1939 3 Sheets-Sheet I5 INVENTOR Patented Nov. 20, 1951 METHOD AND APPARATUS FOR CONTINU- OUS STRIP METAL TREATMENT John S. Nachtman, Youngstown, Ohio Continuation of application Serial No. 257,107,

February 18, 1939.

This

1946, Serial No. 675,897

'Ihisapplication is a continuation of my prior application for Method and Apparatus for Continuous Strip Metal Treatment, filed February 18, l939,=SerialNo. 257,107, now abandoned, which was a continuation-in-part of my application for l manner that it can be collected in separate coils of a desired length. 1

In one phase,- the invention especially pertains to the proper control and handling of metal strip being plated, and particularly, being electroplated. When I speak of strip, it should be understood that I have reference to any suitable form or shape of material and that the principles of the invention are not limited to any particular type of material; of course, a flexible metal material which has been generally designated as metal strip is preferable. It will also be appreciated that certain phases of the present invention deal with the feeding, tensioning, handling,

the joining and the separating of pieces of strip, while other phases deal particularly with a controlled continuous treatment of metal strip.

'Where plating or electrode position forms part 01' the continuous process, the strip may be of any suitable metal. The same, of course, is true of the plated metal. However, for'purposes of illustrating the invention, I have referred particularly to the electroplating of iron or steel strip with tin. In carry-out such a plating process, strip is supplied to the plating line in reels or coils of fairly great length. The process of preparing the strip for plating, washing, drying, etc.. is preferably conducted continuously, one length or strip being suitably secured to another length of strip to form a continuous strip progression for the treating or plating line. It will be apparent that a number of strips may be fed through the apparatus or line at the same time in multiple.

I have found that additional problems have arisen in connection with a continuous treatment of strip from a commercial standpoint as com- 9 Claims. (Cl. sue -2s) application June 11,

pared to a laboratory standpoint. That is, the length of strip undergoing treatment at one time will be greater in the former case and its velocity of movement should be relatively high, much higher than possible heretofore prior to the present invention.

Heretofore, movement of the metal strip through the cleanin pickling, and plating stages has been carried out solely by the pulling action of a wind-up reel or its equivalent that operates at the end of the plating line. I have discovered that in using such an apparatus, the plating of extremely thin strips or fine wires was not possible at high speeds, that is, I discovered that there was a progressive building up of tension in the strip and that this building up was particularly great in the case of a long plating line which is, of course, required in connection with high speed operation. high as well as unsuitable tension of the strip being treated, as well as surging of the line, not only tend to distort the strip but also to spoil the plating operation and the coating provided thereby. That is, I discovered that there are a number of factors involved in electroplating from the standpoint of conveying or moving the strip continuously past or through the necessary treatment zones that entered into the characteristics of the products as well as the effectiveness of the individual and collective treatments.

I also determined that it is important thatsubstantially the same amount of metal should be deposited upon'each unit area of the strip and that as long as the strip passes continuously through the plating line and apparatus at a uniform rate and the current employed in electrode position is constant, the plating thickness can be kept substantially uniform. In case the speed of the strip is varied, the electroplating current should be varied proportionally, and vice versa, in order to provide a uniform deposit.

In view of the above and other considerations. it has been an object of my invention to provide new and improved procedure and/or, apparatus for plating suitable material such as metal strip.

Another object has been to provide a procedure and/or apparatus for continuous and uninterruptedtreatment of a plurality of suitable lengths of strip metal or other suitable material.

Another object has been to provide procedure and/or apparatus for continuously and uninterruptedly moving strip through or past suitable treatment zones and for automatically segregat- 3 ing suitable lengths of the continuous strip thereafter.

A further object of my invention has been to provide new and improved procedure and/or apparatus for suitably tensioning and/or controlling strip material while it is being suitably treated and/or fed.

A further object has been to provide procedure and/or apparatus for suitably proportioning the tension, speed, and rate or treatment of material. parrlzilcularly, while continuously moving the mate A still further object oi my invention has been to provide a commercially practicable continuous plating procedure for utilizing strip metal in coil form.

These and many other objects of my invention will appear to those skilled in the art from the description, the drawings, and the appended claims.

In the drawings Figures 1A, 1B, and 1C are side views in elevation partially sectioned and diagrammatic, which when placed end-to-end from right to left respectively, illustrate a preferred embodiment of my invention.

Summarized briefly, I provide metal strip in coil form, continuously unreel a given piece of strip from its coil, and continuously subject it to suitable treatments. Means is provided, a slack producer, for storing a suitable length of the strip and for continuously paying it out while the trailing end of an exhausted coil is welded, or in another suitable manner, secured to the leading end of a. second or new coil strip. After the strip lengths of two coils have been thus. joined or secured, the slack producing means is operated to take up a suitable length of the strip of the second coil in readiness for later Joining its trailing end to the leading end of a third coil. In this manner, suitable individual lengths of material are continuously fed or passed through various plating operations which may include the steps of pickling, wet-mechanically cleaning. washing, electroplating, washing, and drying.

As it is advantageous to. collect the treated strip in suitable lengths, possibly of substantially the same length as the individual coils at the beginning of the operation, I have provided apparatus that is automatically operable to select strip of suitable lengths and to sever th'eselected lengths and separately coil them. The operation is preferably carried out in such a manner that the tension of the strip being treated ahead of the apparatus is maintained at the desired value irrespective of other operation being done. That is, the tension of the continuous strip being severed and coiled into individual lengths is automatically controlled in such a manner as to not adversely affect the prior operations of the continuous plating line.

In the plating operations, I preferably provide suitably selected driven rolls that are interposed in such a manner as to suitably tension the strip for preceding and succeeding treating operations.

The plating and/or pickling current employed is suitably proportioned to the rate of movement.

or in other words, to the speed of the driven rolls in such a manner that a high efficiency and effectiveness of treatment is obtained. j

Further, in accordance with the present invention, the steps of joining one coil to another,

. of continuously treating the strip, and of severing the strip and recalling suitable severed lengths thereof, are all correlated in such a man- 1B, and 10, respectively. As shown particularly in Figure 1A, one or more coils or reels of strip metal 4 are paid out from positions I over suitable guide rolls 6 to the strip treatment line. In general, the illustrated layout includes, reading from right to left, a payout reel stand or support A. a guide table 13, a welding mechanism C, a guide table D, a slack producer and surge control apparatus E, an electrocleaning apparatus F, a wet-mechanical cleaning unit G,'a cold water rinse bath H, a pickling vat I, a wet-mechanical cleaner J, an electroplating means or unit K, cold and hot baths R and K, respectively, a drier L, a bridle stand or pull rolls M, a photoelectric control unit N, a shearing unit 0, reel selector mechanism P, and a wind-up reel unit Q.

In carrying out the invention, the strip 4 is taken from one of the reels 5, is guided by suitable guide rolls 6 through the welder C over the table D to the pass of a pair of pinch rolls I of the slack producing unit E. The strip is then guided over an idler guide roll 8 of a primary, vertically-movable payout roll carriage III, over a fixedly-positioned idler guide roll Lover an idler guide roll 8 of a. secondary, verticallymovable dancer-roll carriage 2|, and then out over a suitable guide roll 6 to unit F. In normal operation, the position of the strip 4 is indicated by the dotted lines beneath the carriage III while the secondary carriage 20 is in some suitable position such as shown in the drawing. The full line position of the strip shown in Figure 1A is the normal position during welding of the trailing end of the strip of one coil to the leading end of the strip of a second coil.

The lower pinch roll 1 is indicated as being driven bya suitable motor H9 which is constructed and arranged as will be hereinafter more fully explained to provide a desired tension or pull upon the strip adjacent the entrance to the slack producer unit E. i

The payout roll carriage I0 is counterbalanced by a rope or cable ii having a counterweight l3 and is guided over a suitable guide roll 6a and a driven roll or cable-driving pulley II. The pulley I2 is actuated by a reversible payout motor I! to raise and lower the carriage It as will be hereinafter more fully described. In like manner, the secondary or dancer carriage 20 is counterweighted through the agency of a cable or rope H and counterweight 13; the rope ll leaves over pulley guide 6a and rheostat control pulley 22. The pulley 22 is operably connected to an arm of an adjustable rheostatll in such a manner that automatic control is obtained over the pinch roll motor Ill and the payout motor I! in response to oscillation or rotation of the pulley 22, and thus, dependent upon the position of the dancer roll carriage 20. The carriage II maintains a substantially constant tension in the strip, moves vertically in response to operation of the loopproducing carriage l0, and eflectively "irons out line surges without transmitting them.

I The loop-producing carriage- It is provided,- as shown. with an extending switch-operating arm l4 that in its extreme upper position opens a normally-closed payout switch II and that in its extremelower position closes a normally- 'open payout-start-limit switch is. In like manner. the dancer roll carriage is provided with a switch operating arm 2| that first opens a normally-closed emergency slow-down switch 24 and while holding this switch in such a position, opens an emergency-stop switch 25. An emergency-stop-iimit switch I8 is positioned beneath the payout roll carriage l0 and is moved from its normally closed (make) position to an open position (break). if and when the carriage ll moves to its extreme bottom-position.

The strip continuously leaves the slack producer E as a continuous length having a suitable speed and tension. It is shown as then introduced into a suitable electrocleaning tank F having immersed and driven contact rolls II and immersed and cooperating guide rolls i. Current is supplied by generator 32 that is preferably driven at a constant speed by a motor 33; the generator 32 is electrically connected with the contact rolls iii and with a spray pipe assembly 3| positioned above and below the strip 4. The current supplied by the generator 82 may be varied in the conventional manner and is also preferably varied automatically to properly correspond to the conditions of operation as will subsequently be explained.

From the cleaning tank F, the strip 4 passes through a scrubber G having cooperating pairs comprising driven brushes 3!, idler rolls 36, and driven squeegee rolls 36a. Rolls 36 may be driven, if desired, by a motor H8. The sprays for water of suitable temperature have been indi cated by the numeral 31. The strip is then conveyed through acold water wash tank H, between driven tension roll b and a cooperating guide roll 6, through a pickling bath 1, between driven tension roll 35 and a cooperating roll 6, to a driven wet-mechanical cleaning unit J similar to the unit G previously described.

The strip 4 is now ready for'immediate entry into the electroplating bath K and the operation is preferably carried out in such a manner that the cleaned strip will be covered with a coating of the wash fluid, preferably water, after it leaves the unit J until it enters the bath of the unit K. The number of plating elements, etc..

7 of the unit K have been reduced in the drawing IB, but it will be understood that any suitable number may be provided. The unit comprises idle and submerged guide rolls 42 above which are operably-mounted complemental roll pairs which comprise upper, contact and driven rolls 4., and lower, positioning rolls 4i. Motors ill actuate the rolls to provide the necessary electrical contact with the strip and to prevent an undesirable building up of tension of the strip during movement through the bath K. As shown. the rolls 40 are connected to one terminal of a pair of plating generators 44 that arev preferably driven at a constant speed by motor 45;

and in this manner, the strip 4 is converted into. a cathode as it passes in a multiplicity of loops through the bath of the plating unit K. Verti-.

cally-extending anodes 43 of plating material such as tin are disposed in the bath within the spaces ail'orded by the strip loops in such a manner that there are, in effect, two groups of anodes; one group will plate one side of the strip and the second group will plate the other side.

tension and squeegee roll flb, cooperating with a guide roll- I. It then enters and. is guided through cold and hot cleaning baths R and H by suitable guide rolls 4; it is introduced into and leaves the baths by way of pinch roll pairs comprising a driven tension roll lib and a guide I roll 8.

The strip then passes through the drying unit L which may include a drier 41 and nozzles 44. and then enters the bridle stand apparatus M. The bridle stand apparatus or unit M is coordinated with a photo-cell unit N, a shear unit 0, a selector unit P, and a coiling, reeling or wrapping unit Q, in such a manner that the desired tension of the strip is maintained aheadof the bridle stand while at the same time a suitable tension and/or feed of the strip is provided following the bridle stand during the selection of suitable lengths of strip, the severance of those lengths. and the coiling of those lengths into suitable coils. The bridle stand M is, in effect, set into operation through the agency of the photo-cell unit N. In this connection, I preferably punch a hole in the strip after welding one coil toanother adjacent the unit C in order that a beam of light from the lanip ID on one side of the strip will pass therethrough and transmit energizing light to the photo-electric cell ii. The cell ll initiates a number of automatic operations. Of course, it will be apparent that any other suitable means may be employed in this connection for initiating the correlated operation of the units which will be hereinafter more fully explained.

The strip 4 after leaving the drier unit L is guided by roll I into the bridle stand M and over three rubber covered rolls III, 5i, and 52 that serve to drive and tension the strip and to keep it in'check during the cutting and take-oil operations. Roll 60 is operably geared (see Figure 1G) to the roll Ii. Rolls Ill, II, and i2 grip anddraw the strip; roll II is driven by a suitable motor 43-! that is preferably under automatic speed control as will be explained later. A one-revolution mechanical clutch 54 is mounted on the shaft II of the driven bridle-stand roll II.

Clutches of this character are per se well known.

being operable upon actuation to intercouple the clutch with the shaft 55 for aperiod of a single revolution of the latter; the clutch thereafter returns to its initial position for subsequent actuation. The clutch 54 is provided wit-h an arm 58 that is connected by a link to the magnetic core 51 of a magnetic solenoid 51a in such a manner that when the solenoid 51a is energized to lift its core 51, the arm I6 is oscillated to pro- 7 armor;

provided for confining movement in the plane of the strip 4. The other ends of the shear arms 60 carry shear blade supports 61 that are operably mounted above and below the plane of the strip and have rollers 62 for guiding them between a pair of horizontallyextending rails 69. A compression spring is positioned between the upper and lower supports 6| normally to urge them apart or out of an operating position with respect to the strip 4. Pairs 01' cutting blades 63 are mounted upon the ad- Jacent opposite ends of the upper and lower supports 6| in such a manner that they can be thrust towards each other to cut a suitable size piece out of the strip 4, preferably corresponding substantially to the area of weld between the strip of two coils. Thus, the shearing action preferably is timed in such a manner that the overlapped and/or welded terminals or ends of a pair of joined strips are cut in this operation.

A cam element 65 is pivotally mounted at B6 and is provided with a cam face extending beyond the upper and lower rails 69 for operating the shear mechanism. The cams 65 are normally retained in abutment with a fixed stop 68 by a tension spring 6! that is connected between the cam and the stop. As the rollers 62 of the shear carriages 6| travel over the cams 65 to the left. the latter are prevented from swinging by the stop 68 and the shear support carriage 65 and their associated blades are thrust towards each other sufliciently to compress the spring interposed therebetween to cause the blades 63 to sever a section of the strip. Return movement of the shear 63 to its original position illustrated is permitted by the springs 61 without cuttin the strip a second time; that is, the cams are permitted to turn about their pivot points 66 when the rolls 62 of the shear carriages are re turned to their original position from left to right in the drawing in Figure 1C. The cams 65 are thus forced to swing counter-clockwise on their pivots 66 until the rollers 62 have cleared them. The reel selector mechanism or unit P is operated or actuated by the gear 53 which is in mesh with a larger gear 86; the ratio is preferably two to one such that the gear 80 will turn half a revolution upon each actuation of the one-revolution clutch 54. A crank arm 8! is operably mounted on the gear 80 and is pivotally connected to a selector unit operating link 82; the turn, pivotally connected to a pivotally-mounted operating and strip-selecting lever means 83. As shown, the lever 83 has an upper portion that terminates in a selector plate that can be swung to one or the other of two strip guiding positions as illustrated in full and broken lines of Fi ure 1C. In the full 'line (lower) position, the plate of the lever or selector element 83 cooperates with a guide roll 6 and stationary guides 88 and 88 to guide and permit the strip 4 to pass to the lefthand wind-up reel 90a of the unit Q. In this position, the lower switch portion of the selector element 83 has moved the coil motor selector switch 85 to the position shown in such a manner that the motor 9211 is actuated to wind up the lefthand reel 90a. At the same time, the right-hand motor selector switch 84 is pressed to the full line position, by its compression spring opening the line to the armature of the righthand coil wind-up motor 92b. Thus, the righthand motor 92b and its associated coiler 90b are stationary at this time.

When the selector arm its "extreme right position,

83 has been moved to the 'leithand selector this axis to horizontal switch 4| opens the armature circuit of the lefthand wind-up motor 82a and closes the armature circuit of the rlghthand motor 92b through the agency oi the rlghthand selector switch 84, see the dotted line position, 0! this latter switch. In this position, the deflector plate portion of the lever 83 is raised to intercept the oncoming severed strip end and to direct it over guide plate 81 to the righthand coiling reel 90b. Actuation oi the selector mechanism P closely Iollows and is timed to the shearing step which takes place during the first quarter revolution of the mechanical clutch. For each full cycle shearing operation, there is thus only a one-halt cycle operation of the selecting mechanism. In the case of both of the coils 80a and Nb, a belt wrapper mechanism 8| .0! conventional design is operable to catch an oncoming end or a severed strip and to start it around the empty reel or drum as it is turned by its motor 92a or 92b for reception of the elongated strips.- Such belt wrappers are well known and form per seno part of the present invention.

The actuating or motor drive for driving the various contact, pinch, and/or tension rolls by the numeral H8. The fields of the motors I It as well as the fieldsot the wind-up motors 92a and 92b, of the slack-producer pinchroll motor I IQ, of the payout carriage drive motor of the bridle stand motor 63-1. and a sepalink is, in v 7 speed of rately-exclted field 95 or generator 93 are sum plied with current by a suitable constant voltage generator HI, Figure 10, connected to constant voltage supply lines 2 and H3. A constant speed motor H0 drives the generator III as well as a variable voltage generator H5. The arma ture of the variable voltage generator 5 is connected to the current supply lines Hi and III which, in turn, provide the current for actuating the armatures of the motors H8, 1 l8. l9, and 63l. The separately-excited field vi the gemerator H5 is controlled by resistance I21 and control rheostat 120 to vary the current supplied to the mains H6 and I". It will also be noted that the fields of the electrocleaning gen:- erator 32 and of the electroplating generator armatures 44 are connected to the current supply mains I I8 and H1 in such a manner that their field excitation will vary in proportion to the the motors above-mentioned.

The armatures of wind-up motors 92 are sup-.- plied with current by a generator 93 that is driven by a suitable motor 96 and has a separately-excited field 95 and a shunt salt-excited field .84 and a diflerential series field 54a. A lefthand contactor mechanism 91, Figure 1C, having three pairs or sets of contact points, controls the supply oi actuating current to the armature of the lefthand wind-up motor 921: from the generator 93 which is preferably driven at a constant speed and delivers a normally constant horsepower output. As shown, it is provided with differentiallycompounded field coils 94, 94a, and 95. The

. righthand contactor 98 is in like manner provided with'three pairs of contact points for controlling the supply ofcurrentrrom the supply generator 93 to the motor 921:.

The photo-cell control when the photo-cell II is energized by receiv- 7'5 ing light from the source 10 through a hole in,

or through an intentionally placed irregularity on the strip 4, it will energize a holding coil II of a control relay I2 that, in turn, energizes the solenoid 01' a time delay relay I9. When the time relay I9 is energized, it will open a normallyclose contact TI and insert resistance 19 into the circuit feeding the field of the bridle stand motor 93--I and the separately excited field 99 of the wind-up motor generator 93. This will increase the pull on the strip exercised by the bridle stand motor 93-4 as applied to the rollers ll and 92 and will decrease the pull on the right, or left, wind-up motor 92a or 92b, as the case may be, to thus eflect a low tension pull (enough to take up slack) by the righthandreel 99b upon the strip that is to be sheared. That is, the throwing oi' the resistance I9 in the separately excited field 99 of the generator 93 will decrease the current supplied by it to the wind-up motor 92a or 92b.

The contactor I2 on closing will also energize the coil of the solenoid 91a to raise the magnetic core El and oscillate the arm 59 and produce an engagement of the one-revolution mechanical clutch 54, which operates the shear as previously explained. Assume for the purpose of this discussion that the strip is being fed to the lefthand coiler 99a and that the selector switch 95 is closed to actuate the lefthand wind-up motor 92a. Then, the strip 4 will be severed by the actuation of the clutch 54 and the shear mechanism the selector arm 93 will be moved to the right by the operative engagement between the clutch gear 53 and the operating wheel 99. The righthand movement of the selector arm 83 will cause the holding coil 98 to be de-energized and the holding coil I99 to be energized. Thus, the switch contact points of the contactor 91 will be opened and those of the contactor 99 will be closed to actuate the armature oi the righthand wind-up motor 92b, and thus, the righthand wind-up reel 99b. Simultaneously therewith, the selector plate moves the cut end of the strip down along the guide 81. 4

During the time that the switch selector arm 33 is leaving switch 85 and is moving towards switch Starting 0r initiating the operation of the line The apparatus is started by first moving ad- Justabie arm of'start rheostat I29, see Figure 18, to contact point I2I. At this time. a resistance I21 is connected between the rheostat I29 and the separately-excited field of the variable voltage generator H9. The closing or the contact point I2I directly connects the holding 0011 I29 of a general line contactor switch I25 to the motor field current supply line II3; the other side 01' the coil I29 is directly connected to the line H2. The energization ofthe general line contactor switch I29 closes its three pairs or sets of contact points, the left set of which connects the switch side of the armature of the generator III to the motor armature and generator field current supply line I H, the center set of which energizes the separately excited fields of the plating generators 44 through the lines I I9 and I I 'I, and the right set oi. which connects the side oi. the relay coil I29 that was closed by the rheostat I 29 to the line I I3 through an emergency stop contactor I29, Figure 1A. Thus, the contactor I29 will remain closed when the arm of the starting rheostat I29 is moved off point I2I to the left 01' Figure 1B and suitably resistance-adjusted to provide a desired strength 01' field for the generator II9.

- It will be noted that the closing of the righthand switch points or the contactor I29 also closes 84, both contactors 91 and 99 will be open and the armatures of both of the wind-up motors 92 will be ole-energized. Mechanical interlocking means I M i provided for preventing a simultaneous closure of both contactors 91 and 99, but permitting a simultaneous opening of them. The opening of the switch contact points of the lefthand contactor 91 will de-energize the relay coil I3, the coil of the time delay relay l9, and the coil of the clutch operating solenoid 51a. The coil of the time delay relay I9, however, will not close its contact 'II immediately, but will remain open for a definite time period following the deenergization of its coil. This time delay is sufllcient to keep the resistance I8 in the field of the motor 93-I and the field 95 of the generator 93.

while the selector lever 93 moves from its lefthand position and closes the righthand selector switch 84. This, of course, energizes the coil I99 of the righthand contactor 99 and closes the switch contact points thereof to insert the righthand wind-up motor 92b in the operating circuit. The leading end of the strip 4 upon reaching the reel 0! 99b will be wrapped around the reel block several times by the belt wrapper 9| and then the wrapper will be withdrawn. At this time, the

contact arm 11 of the time relay I9 will open,

short-circuiting the field resistance I8 and increasing the strength of the field oi the bridle the connection between the line I I3 and one side of the light source I9, Figure 1C, and of the selector circuit P which includes the switches 94 and and contactors 91 and 99. In other words, it will appear that the excitation of the field 99 of the wind-up motor supply generator 93 will depend upon the position of the righthand pair of contact points or the contactor I25, and that the wind-up motors 92a and 92b will be actuated depending upon the position or theselector arm 93 to initiate the actuation of one of the wind-up reels 99a or 99b. The closing or the point I2I' of start rheostat I29, in addition to energizing the armatures oi the various motors such as H9, H9, 93, and 92, also, as previously set forth, energizes the fields oi. generators 93, 44, and 32. After the starting has been accomplished, the arm of the rheostat I29 may be moved along the resistance to control the voltage of the field oi. generator H5 to set it to provide a desired voltage for the armatures of the various motors as well as for the fields of the electroplating and electrocleane ing generators 44 and 32, respectively. 9

Operation of continuous feeding while welding set of which connect opposite sides of the arma ture of a payout motor I9 to the current supply mains H9 and Ill. The motor 19 is thus actuated to turn the pulley i2 and raise the payout roll carriage I to provide a reserve or loop of the strip 4. When the payout carriage l0 reaches the top of its travel, it will be stopped automatically by payout switch I which is opened by the extending arm I4.

After the strip c0115 is completely paid out, the operator will press a stop-payout switch (break) button I35 that will de-energize holding coil I of a pinch roll control contactor I40; this, in turn, will disconnect the armature of the pinch roll motor I I9 from the current supply line H1. It will be noted that the left and center pairs of contacts of controller I40 are of the make type while the righthand set or pair are of a "break" type; thus. the latter will make" at this juncture to energize holding coil I45 of contactor I38 through line H3 and the closed contacts of stop-limit switch I8. The actuation of holding coil I45 will, in turn, close three sets or pairs or switch contacts, the first two of which reverse the current supply leads H5 and H1 to the armature of the payout motor l9 and the third or righthand set will close the holding circuit in parallel with contacts I42. The payout carriage control motor l9 will thus be actuated in a reverse direction to lower the payout carriage I0, and to feed the strip to the plating line as needed by progressively decreasing the size of the loop beneath the carriage. The dancer roll' carriage 20 will automatically regulate the speed oi the payout motor I9 through the operative connection of the pulley 22 with the field current control rheostat 23 to give a uniform payout of strip to the plating line. Push break switch I44 provides for an emergency stop of motor l9 when carriage I0 is being raised.

The operator will weld the leading endof a new coil of strip to the trailing end of the exhausted coil at the welder C while the carriage I0 is being moved downwardly. As the carriage I0 approaches its lower position, it will reclose the (normally open) payout-start-limit switch It and current will flow from the supply line I It to the coil I of the contactor I40 to energize the coil and close its first and second pairs of contacts (from left to right). Its right set I42 are opened. The opening of the contacts I42 has no eiiect, as it is paralleled by the holding circuit on switch I45. The closing of the make pairs of contacts ofthe contactor I40 connects the armature of the pinch roll motor H9 to the supply line I", thus initiating its movement. It will be lowest position, it will be stopped automatically by stop-limit switch I8. That is, the carriage strikes the switch I9 and breaks" or opens it. Should any emergency condition arise whereby noted that rheostat 23 also controls the speed of the motor H9 would fail to start at the time the payout carriage l0 recloses the payout start limit switch I 0, the carriage I0 will continue on to the bottom and stop, and since the line is receiving strip and no further strip can be paid out by the carriage I0, the dancer roll carriage 20 will lower automatically. As the dancer roll carriage 20 reaches the emer ency slow-down switch 24, its extending arm 2| will break or open it, and this will, in turn, tie-energize emer gency slow-down contactor coil I30, opening its contact points and inserting resistance I21, see Figure 1B, in the field of variable-voltage line current supply generator H5, see Figure 10; this will bring the strip driving motors H8, the pinch roll motor H9, the bridle stand motor 83-I, etc., down to a creeping speed and will cut down the field energization of the generators 32 and 44 in proportion thereto. If the emergency is such that the dancer roll 20 continues to move downwardly, its arm 2| will continue to hold the switch 24 open and additionally will open or break" the emergency stop switch 25 which will, in turn, de-energize contactor coil I29. The opening of the lefthand portion of the contactor I28 through the de-energization oi! the coil I29 will, in turn, cause a de-energization of the coil I20 of the contactor I25 and an opening of the entire line circuit. Thus, the generators are deenergized and the motors are stopped. The plating line only can then be started by raising the dancer roll frame 20 to its normal operating position.

In accordance with a preferred operation, the pinch roll motor H9 as well as the bridle stand motor 63-4 are normally driven to provide a drag tension. During severance of the strip at O, the motor 03-I is adjusted by field control 18 to increase its torque to provide a for.- ward pull on the strip 4; the wind-up motor 92a or 921) is changed from a forward to a substantially zero pull (enough to take up slack). It, therefore, follows that the shearing operation is accomplished under conditions of minimum tension. I haveiound to prevent tearing and distorting of the strip and also to permit an uninterrupted continuation of the plating operations or line treating operations and to initiate the coiling of a new section or length of the strip that is being fed. It is apparent that the automatic control of the present invention makes possible a high flexibility of operation such that the desired arrangements can be carried out regardless oi the particular operations involved. I have found that the strip can be tensioned properly during the treating operations and that line surges such as may arise particularly in a long line can be welded to the leading end of a new coil at the unit C, the pin roll motor H9 is then preferably adjusted in effect. to tension the strip or hold it back in the direction of its normal movement; this gives the welder an opportunity to attach quickly the two coil ends together and thereafter normal operation again may be assumed.

Although for the purpose of illustration, I have applied my invention to an electroplating line and have used a particular type of layout preferably employing direct current roll-driving m tors for simplicity of control and operation, it will be apparent to those skilled in the art that other suitable arrangements and connections may be employed as well as any suitable type of motivating means without departing from the spirit and scope of the invention as indicated in the appended claims. It will also appear that the present invention makes possible a substantially complete automatic operation of a series of treating steps upon a piece of material that is provided in suitable separate lengths and that after treatment again may be cut and gathered into suitable lengths without disturbing the continuous operation of the treatment line. It will also be apparent that the invention makes possible a suitable practicable control and tensioning that this is highly desirable similar to that oi motors I".

13 of the strip on the basis of any particular treatment to which it is to be subjected 'at any point along the line, regardless of prior or after types of treatments. In view of these andother considerations,- it is felt that the present invention shouldnot be limited to particular details and structural parts but that suitable modifications. additions, substitutions, omissions, etc, may be made without departing from the spirit and scope oi'- the invention. For example, it it is desired that strip be cut to length after treatment in the line, a leveller, flying shear, and piler may be used in place oi reels "a and! and their associated apparatus. Obviously, in such a case, the bridle-stand motor "-4 will be adjusted to provide a forward torque, and leveller, shear, and piler motors will have connections I claim: 1.In a method of continuously electroplating coiled discontinuous metallic strip with coating of metal, the steps 01' unreeling said discontin ous metallic strip from supply coils, joining e discontinuous strips end to end, conveying the Joined strips uninterruptedly under tension through a loop variable in response to tension changes and then in a fixed path through an electroplating operation by applying propulsive power to the strip after said electroplating operation, automatically segregating the plated strip into discontinuous lengths and automatically recoiling said discontinuous lengths, establishing a predetermined tension in the strip by.

applying power to the strip between the unreelingcoils and said variable loop, and automatically regulating the rate of unreeling strip by controlling the magnitude and direction of the tension-establishing power in-response to variations in said variable loop due to tension changes,

2. In a method of continuously electroplating coiled discontinuous metallic strip with coating of metal, the steps of unreeling said discontinuous metallic strip from supply coils, Joining thediscontinuous strips end to end, conveying the joined 'strips 'uninterruptedly under tension through a'loop variable in response to tension changes and then in a fixed path through an electroplating operation by applying propulsive power to the strip after said electroplating operation, automatically segregating the plated strip into discontinuous lengths and automatically recoiling said discontinuous lengths, establishing a predetermined tension in the strip by applying power to the strip between the unreeling coils and said variable loop,.accumulating a portion of'the unreeling strip in a storage loop between the point of applying the tension-establishing power and the electroplating operation while automatically regulating the rate of unreeling strip from said coils by controlling the magnitude and direction of the tension-establishing power in response to variations in said variable loop due to tension changes. stoppin a portion of the lmreeled strip between the storage loop and said supply coils and simultaneously starting paying out strip from the storage loop through the electroplating operation, and automatically regulating the rate of such paying out from the storage loop in response to variations in said variable loop due to tension changes.

3; In a method of continuously electroplating a metallic coating on metal strip supplied in discontinuous lengths irom coils requiring a varying pull, the steps or moving the strip from the coils l4 continuously at predetermined speed in a fixed path through an electroplating operation by applying propulsive power to the strip after the electroplating operation, establishing a predetermined tension in the strip passing through said electroplating operation by applying power to the strip between said electroplating operation and said supply coils, and automatically regulating the magnitude and direction of said tension-estabiishing power in response to tension changes in the strip portion between the point of applying said tension-establishing power and said electroplating Operation to compensate for the varying pull oi the supply coils and maintain said predetermined tension in said strip portion.

4. In the method as defined in claim 3, the step of applying propulsive power to the strip within the electroplating operation in an amount equal to the power required to prevent a building up of tension in the strip in said electroplating operation.

*5. In the method as defined in claim 3, the step of automatically regulating the electroplating current in the electroplating operation in direct proportion to the strip speed to give a uniform thickness of electroplated coating.

6. In a method of continuously electroplating metal strip supplied from coils, the steps of unreeling strip from saidv coils continuously at a predetermined speed through a fixed path in an electroplating operation by applying propulsive power to the strip after the electroplating operation, establishing a predetermined tension in the strip passing through said electroplating operation by applying power to the strip between said electroplating operation and said supply coils. accumulating a portion of the unreeling strip in a storage loop between the point of applying said tension-establishing power and the electroplating operation in preparation for attaching a new supply coil to the end of an unreeled coil, then adlusting said tension-establishing power to stop the strip momentarily for attaching said new coil and simultaneously starting paying out strip from said storage loop, and then while starting unreeling from said newly attached coil automatically regulating said tension-establishing power in response to tension changes in the strip portion between the point of applying power and said electroplating operation.

7. In apparatus for continuously electroplating continuous strip metal, an electroplating unit for continuously electroplating the moving strip, means for propelling the strip continuously under tension at predetermined strip speed from separate coils through the electroplating unit, motor drive means for paying out the strip from the coils to said electroplating unit, a movable carriage for maintaining a variable loop in the strip between the payout drive means and the electroplating unit, a movable strip storage carriage between thepayout drive means and the electroplating unit, means for driving selectively said storage carriage to create a storage loop and to pay out strip therefrom, and means operatively connecting the storage carriage drive to said variable loop carriage for automatically regulating the rate of payout from the storage loop in response to variations in the variable loop due to tensionchanges therein.

8. In apparatus for treating a continuous length of metal strip, a support for holding a coiled length of metal strip, pull rolls spaced from said support for pulling strip from said support through said apparatus, electroplating means between said pull rolls and said support, a first cleaning means between said electroplating port and the first cleaning means for applying drag tension to said strip,,welding mechanism adjacent said support for joining successive lengths of metal strip to form a continuous strip, control means for stopping saidstrip at said welding mechanism during the joining of successive lengths, said pull rolls and motor withdrawing strip from said storage loop and pulling said strip through the first cleaning means, electroplating means and second cleaning means at substantially constant speed while said strip is stopped at said welding mechanism and means following said pull rolls on the discharge side opposite said support for cutting said strip into predetermined lengths while said strip is .being continuously moved by said pull rolls through said first cleaning means, electroplating means and second cleaning means.

, 9. A method of electroplating a continuous length of metal strip, comprising essentially the steps of supplying metal strip 'in discontinuous lengths, then welding such lengths of strip together end to end with good contact between successive lengths to form a continuous strip, then forming a storage loop of the continuous strip, then cleaning the continuous strip, then electroplating the cleaned continuous strip, then cleaning the electroplated strip, pulling said strip through said first cleaning, electroplating and second cleaning steps continuously and at substantially'constant speed, stopping the portion of said strip being joined during the welding operation while withdrawing strip from said storage loop, applying drag tension to said strip between the supply and the first cleaning operation, con-. tinuously moving the strip through the first cleaning, electroplating and second cleaning operations under predetermined tension and cutting the cleaned electroplated strip into predetermined lengths 'while continuously moving said strip through the first cleaning, electroplating and second cleaning operations.

JOHN S. NACHTMAN.

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

UNITED STATES PATENTS Number Name Date 1,120,191 Gibbs Dec. 8, 1914 1,242,695 -Hood Oct. 9, 1917 1,517,910 Kirsohner Dec. 2, 1924 1,533,447 Newman Apr. 14, 1925 1,811,522 Shover et al June 23, 1931 1,928,409 Coe Sept. 26, 1933 1,991,817 Nachtman Feb. 19, 1935 2,007,614 Prentice July 9, 1935 2,009,856 Otis et al July 30, 1935 2,052,255 Shoulte Aug. 25, 1936 2,066,565 Iverson Jan. 5, 1937 2,075,332 Antisell Mar. 30, 1937 2,076,969 Sieger Apr. 13, 1937 2,201,417 Webster May 21, 1940 2,238,667 Wales Apr. 15, 1941 2,240,265" Nachtman Apr. 29, 1941 2,266,330 Nachtman Dec. 16, 1941 2,325,401 Hurlston July 27, 1948 2,459,674 Nachtman Jan. 18, 1949 FOREIGN PATENTS Number Country Date 427,436 Germany Apr. 13, 1926 279,787 Great Britain Sept. 6, 1926

Claims (1)

1. IN A METHOD OF CONTINUOUSLY ELECTROPLATING COILED DISCONTINUOUS METALLIC STRIP WITH COATING OF METAL, THE STEPS OF UNREELING SAID DISCONTINUOUS METALLIC STRIP FROM SUPPLY COILS, JOINING THE DISCONTINUOUS STRIPS UNINTERRUPTEDLY UNDER TENSION CHANGES AND THEN IN A FIXED PATH THROUGH AN ELECTROPLATING OPERATION BY APPLYING PROPULSIVE POWER TO THE STRIP AFTER SAID ELECTROPLATING ELECTROPLATING OPERATION BY APOPLYING PROPULSIVE POWER TO THE STRIP AFTER SAID ELECTROPLATING OPERATION, AUTOMATICALLY SEGREGATING THE PLATED STRIP INTO DISCONTINUOUS LENGTHS AND AUTOMATICALLY RECOILING SIAD DISCONTINUOUS LENGTHS, ESTABLISHING A PREDETERMIED TENSION IN THE STRIP BY APPLYING POWER TO THE STRIP BETWEEN THE UNREELING COILS AND SAID VARIABLE LOOP, AND AUTOMATICALLY REGULATING THE RATE OF UNREELING STRIP BY CONTROLLING THE MAGNITUDE AND DIRECTION OF THE TENSION-ESTABLISHING POWER IN RESPONSE TO VARIATIONS IN SAID VARIABLE LOOP DUE TO RENSION CHANGES.

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