STRIP TREATING APPARATUS

Abstract: An apparatus for treating a strip such as a steel sheet. A first object is to provide an electrode switching device of a simple construction. A second object is to uniform the flow of the treating liquid around the electrodes. A third object is to prevent uneven treatment caused by variation in liquid level of the treating liquid between the electrodes. To attain the first object, there is provided a switching device for fixing one of the mutually facing electrodes and moving the other. To attain the second object, flow straightening plates are provided to the electrodes to define liquid staying spaces between the electrodes and the flow straightening plates, and slots for permitting the treating liquid to uniformly flow between the electrodes from the liquid staying spaces are made in a direction perpendicular to the movement of the strip. To attain the third object, bus bars for supporting the electrodes are curved at portions supporting the electrodes, whereby the electrodes are always immersed in the treating liquid.

Description: The present invention relates to an apparatus for treating a strip such as a steel strip, for example, a plating apparatus, a cleaning apparatus and the like, and especially to a strip treating apparatus in which homopolar electrodes as anodes or cathodes are arranged so as to face to each other in a bath tank, and a strip is travelled between these electrodes. For the purpose of increasing production and improving productivity in the above-described strip treating apparatus, it has been required to decrease the distance between a strip and each of the electrodes such as anodes or cathodes, to stir a treating solution such as a plating solution between the strip and each of the electrodes such as anodes or cathodes, and to supply ions between the strip and each of the electrodes such as anodes or cathodes. In view of these circumstances, the applicant has developed an apparatus in which insulators (stabilizers) are provided so as to be projected face to face or in zigzags on opposite inner surfaces of homopolar electrodes arranged so as to face to each other, and each of these insulators is provided with a slant face inclined from a side of the electrode toward the strip in a travelling direction of the strip (Japanese Patent Provisional Publication No. H3-20494). It became thus possible to extremely decrease the distance between the homopolar electrodes so as to remarkably improve productivity with the use of the strip treating apparatus. However, the above-described strip treating apparatus has involved problems, and has been required to be further improved. There is the first problem which relates to a mechanism for adjusting the distance between the electrodes. In the above-described strip treating apparatus, the distance between the electrodes is extremely short. Use of the electrodes stationarily arranged thus makes it impossible to pass a rope between the electrodes, which is to be used for passing the strip through the strip treating apparatus prior to the start thereof. The connecting portion of the strips by means of a welding and so on has a relatively large thickness. It has therefore been considered at the time of development of the apparatus that the above-mentioned connecting portion would be in contact with the stabilizer to cause the breakage thereof. For these reasons, there has been required a mechanism for opening and closing the electrodes. There have conventionally been provided an opening and closing mechanism and operating members thereof, in which both of the electrodes were openable against each other as shown in Fig. 13, in order to secure a space necessary for an operation of passing a rope between the electrodes, which is to be used for passing the strip through the strip treating apparatus prior to the start thereof, and to prevent the welded portion of the strips from being in contact with the stabilizer during travelling of the strip. A treating solution such as a plating solution (not shown) is filled in a vertical-pass type bath tank 1 as shown in Fig. 5. As electrodes 2, there may be used one of anodes and cathodes, or electrodes which are changeable into anodes or cathodes. The upper portions of the respective electrodes 2 are supported by means of upper electrode-holders 3. On these upper electrode-hold er 3, there are provided pneumatic cylinders 4 for opening and closing the upper portions of the electrodes. The lower portions of the respective electrodes 2 are supported by means of lower electrode-holders 5. On these lower electrode-holders 5, there are provided cams 6 for opening and closing the lower portions of the electrodes. The opening or closing of the electrodes is carried out by operating all of the pair of pneumatic cylinders 4 and the pair of cams 6 for each electrode. Both of the electrodes are movable in this manner. There has been a necessity of securing in the bath tank 1 a space necessary for moving also the electrode arranged farthest from a conducting drum 7, i.e., the electrode 2a arranged at the side of the wall of the bath tank 1, and a large-sized bath tank has therefore been required, leading to an increased cost. When the strip treating apparatus was attempted to be mounted on the conventional bath tank 1 in which there could not be prepared the above-mentioned space, there has been a problem of necessity of modifying the bath tank 1. In addition, the operating members for the cams 6 for opening and closing the lower portions of the electrodes 2 have necessarily been arranged so as to project outside from the side wall of the bath tank 1, and more specifically, holes for these operating members have necessarily been formed in the bath tank 1, thus leading to a problem of leakage of the bath. After a practical operation, it has been recognized that a welded portion formed by lap-welding the strips each having a thickness of 1.2 mm could pass through between the stabilizers arranged apart from each other by a distance of 6 mm, without being in contact with the stabilizers. It has also been recognized that the opening and closing of the electrodes 2 was required only when carrying out the operation of passing the rope between the electrodes, which is to be used for passing the strip through the strip treating apparatus prior to the start thereof. The above-mentioned facts have been to confirm the solvability of the problems described above, as well as the possibility of installing the strip treating apparatus in a smaller space. In view of the foregoing, at least in the preferred embodiment there is provided a strip treating apparatus such as a plating apparatus or a cleaning apparatus, which has an opening and closing mechanism for electrodes, which is able to be secured to a small-sized bath tank designed as a facility having the irreducible minimum scale of a demand, or the conventional bath tank, and in which mechanism a leakage of a bath is prevented. According to the present invention there is provided apparatus according to claim 1. When the homopolar electrodes are arranged vertically so as to face to each other in the bath tank, all of operating members of the opening and closing mechanism are preferably positioned above the surface of a bath in the bath tank. The opening and closing mechanism may comprise a pair of electrode holders positioned on both end portions of the other electrode, frame-shaped followers provided at the both end portions of the other electrode, cam shafts rotatably supported on the electrode holders, cams secured to both end portions of the cam shafts, and fitted into the frame-shaped followers, and operating members provided at one end portions of the cam shafts. When the homopolar electrodes are arranged vertically so as to face to each other in the bath tank, the opening and closing mechanism may comprise a bus bar connected to an upper end of the other electrode, upper electrode-holders positioned on an upper end portion of the other electrode, a sliding system for slidably supporting the bus bar on the upper electrode-holders, and a linear-type actuator for sliding the bus bar on the sliding system. A function of the strip treating apparatus of the preferred embodiment will be described hereafter. One electrode of homopolar electrodes which are to be arranged so as to face to each other is arranged at a prescribed position, and stationarily secured thereto. The other electrode is movably arranged at a prescribed position, and an opening and closing mechanism for the other electrode is provided. When passing through a rope between the electrodes, which is to be used for passing a strip through the strip treating apparatus prior to the start thereof, the other electrode is only opened to obtain a prescribed distance necessary for passing through the rope between the electrodes. In this stage, the above-mentioned one electrode is stationarily secured at the prescribed closed position. Since insulators (stabilizers) are also provided on this electrode, the strip may slide on the insulators without being in contact with this electrode during the passing of the rope between the electrodes, which is to be used for passing the strip through the strip treating apparatus prior to the start thereof, thus preventing the contact of the strip with the electrode. In this stage, the insulators (the stabilizers) are not damaged or broken, since the strip is not tensed. The construction in which the electrode on the side of the wall of the tank is designed as the stationary electrode, permits the use of a small-sized bath tank, since there is no need of preparing a space for moving the above-mentioned electrode, and also permits the application of the strip treating apparatus to a conventional bath tank which does not have such a space. Since the opening and closing mechanism provided only for the other electrode suffices, the cost of the opening and closing mechanism can be reduced by half. In case that the homopolar electrodes are arranged vertically so as to face to each other in the bath tank, it is possible to release the necessity of forming holes for operating members of the opening and closing mechanism in the wall of the bath tank and of arranging the above-mentioned operating members so as to project outside from these holes, by arranging all of the operating members of the opening and closing mechanism above the surface of the bath in the bath tank, resulting in prevention of leakage of the bath, and prevention of the damage of the operating members caused by the immersion of the operating members in the bath. The operating members mean portions which generate the force for operating the opening and closing mechanism, they mean portions to be operated by hands of an operator, if manually operated, and they mean portions which generate the operating force, i.e., operating portions of rotary-type actuators such as rotary-type cylinders, linear-type actuators such as pneumatic actuators, and the like, if automatically operated. The opening and closing mechanism comprises camshafts rotatably supported on a pair of electrode holders, having cams secured thereto in respective positions of both end portions of the other electrode, and having the operating members at the respective end portions; and a pair of frame-shaped followers which are respectively secured onto the both end portions of the other electrode, and into which followers the cams of the cam shafts are respectively fitted. According to this construction, it is possible to compose the opening and closing mechanism in a small-size and in a simple construction. In addition, the both end portions of the other electrode are moved so as to be opened or closed by means of the cam shafts supported on the pair of electrode holders, thus securing the opening and closing operation. In case that the homopolar electrodes are arranged vertically so as to face to each other in the bath tank, the opening and closing mechanism comprises a sliding system provided between upper electrode-holders and a bus bar for the other electrode, and a linear-type actuator for sliding the other electrode on the sliding system. According to this construction, it is possible to move the other electrode in low friction, with the result that the electrode can be moved by a small force, thus making it possible to use small-sized actuators. Various embodiments of the present invention will now be described, by way of example only, together with other arrangements given for illustrative proposes only with reference to the accompanying drawings in which: Fig. 1(a) is a perspective view illustrating the strip treating apparatus of the preferred embodiment of the present invention, and Fig. 1(b) is a descriptive plane view illustrating the fitting condition of the cam into the frame-shaped follower as shown in Fig. 1(a); Fig. 2 is a perspective view illustrating the modified embodiment of the strip treating apparatus as shown in Fig. 1; Fig. 3 is a perspective view illustrating the strip treating apparatus of another preferred embodiment of the present invention; Fig. 4 is an enlarged front view illustrating the opening and closing mechanism of the modified embodiment of the strip treating apparatus as shown in Fig. 3; and Fig. 5 is a perspective view illustrating a conventional strip treating apparatus. An embodiment of the strip treating apparatus of the present invention will be described hereafter with reference to the drawings. A plating solution (not shown) is stored in a vertical-pass type bath tank 1, and anodes 2, 2 are vertically arranged face to face in the plating solution so that the upper end portions 2d, 2d of the anodes 2, 2 are located above the surface of the bath (not shown) in the bath tank 1, as shown in Fig. 1(a). Insulators (stabilizers) are provided so as to be projected on the inner surface of each of the electrodes 2. Each of the insulators has a slant face (not shown) inclined from the side of the electrode toward the strip in the travelling direction of the strip (i.e., in the downward direction in Fig. 1(a)). A bus bar 2c is secured to the upper end of the electrode 2. An electric current is supplied through the bus bar 2c to the electrode. One electrode 2a of the homopolar electrodes arranged so as to face to each other is stationarily secured. More specifically, upper electrode-holders 3 and lower electrode-holders 5 are secured in the bath tank 1 so that bus bar fitting portions 3a of the upper electrode-holders 3 and bus bar fitting portions 5a of the lower electrode-holders 5 are placed at the respective prescribed positions, the bus bars 2c respectively provided at the upper and lower ends of the one electrode 2a are fitted into the above-mentioned bus bar fitting portions 3a, 5a. The one electrode 2a is arranged at a prescribed position and stationarily secured thereto in this manner. The upper electrode-holders 3 are arranged above the surface of the bath in the bath tank 1. The one electrode 2a may be stationarily secured in close proximity to the wall of the bath tank 1. The upper bus bar 2c for the other electrode 2b is slidably mounted on the upper electrode-holders 3. The other electrode 2b is therefore openable and closable relative to the one electrode 2a. Stopper portions 3b, 5b for limiting the sliding position of the other electrode 2b under the closed condition are provided on the upper and lower electrode-holders 3, 5, respectively. There is provided an opening and closing mechanism 20 for the other electrode 2b. More specifically, cam shafts 20a are rotatably supported in the upper and lower pairs of electrode-holders 3, 5, respectively. Cams 20b are secured to the cam shafts 20a at positions of the both end portions of the other electrode 2b. Operating members 20c comprising manually operated levers are fixed to the respective upper ends of the cam shafts 20a. The operating members 20c are arranged above the surface of the bath in the bath tank 1. Each of the cams 20b comprises a disc-shaped eccentric cam as shown in Fig. 1(b). When the manually operated lever 20c is turned to a position at right angle to the electrode, the other electrode 2b is moved and urged against the stopper portions 3b, 5b so as to set the other electrode in the closed position. When the manually operated lever 20c is turned to a position parallel to the electrode, the other electrode 2b is moved together with frame-shaped followers 20d described later so as to set the other electrode in the opened position. The eccentricity of the cam 20b is previously determined so as to secure a prescribed distance between the electrodes, which permits the passing of a rope between them by only moving the other electrode. The frame-shaped followers 20d are provided at the both end portions of the other electrode by securing these followers 20d to the bus bars 2c. Each of the frame-shaped followers 20d has a rectangular space, and the short side of this rectangular space has a length substantially identical to the longer diameter of the cam 20b so that the cam 20b is fitted into the frame-shaped follower 20d. When the eccentric cam 20b is turned, the frame-shaped follower 20d follows the eccentric cam 20b to change its position. A conducting drum 7 is arranged in the bottom portion of the bath tank 1. The strip travelling between the pair of electrodes 2, 2 is stretched over the conducting drum 7 so as to change the travelling direction thereof. When there is conducted a work of passing through a rope between the electrodes in the strip treating apparatus having the above-described construction, prior to the start thereof, the manually operated lever 20c is turned to a position parallel to the electrode (as shown by dotted lines in Fig. 1(b)). As a result, the frame-shaped followers at the both of the upper end portions and the lower end portions of the other electrode move in the following action of the turning of the eccentric cams, to cause the other electrode to be set in the opened position. In this stage, the both of the upper end portions and the lower end portions of the other electrode are moved, thus ensuring the opening and closing. The opening and closing operation can easily be conducted by only turning the manually operated levers 20c arranged above the surface of the bath in the bath tank. In this stage, the one electrode is stationarily secured at the prescribed closed position, as mentioned above. Since the insulators (the stabilizers) are provided on this electrode, the strip may slide on the insulators without being in contact with this electrode during the passing of the rope between the electrodes in the strip treating apparatus prior to the start thereof, thus preventing the contact of the strip with the electrode. In this stage, the insulators (the stabilizers) are not damaged or broken, since the strip is not tensed. After the completion of the work of passing through the rope between the electrodes in the strip treating apparatus prior to the start thereof, the strip is stretched over the conducting drum 7 so as to change the travelling direction thereof. Then, the manually operated lever 20c is turned to a position at right angle to the electrode (as shown by solid lines in Fig. 1(b)) As a result, the frame-shaped followers 20d move in the following action of the turning of the eccentric cams in a direction opposite to that in the above-described opening operation, to cause the other electrode to be set in the closed position. When the other electrode is in contact with the stopper portions 3b, 5b, the closing operation is completed. The closing condition of the other electrode can be firmly maintained by urging the bus bars 2c against the stopper portions 3b,5b by means of the eccentric cams 20b. Each of the manually operated levers has a prescribed length so that it can be turned by a small force under the action of leverage. After the thus completion of the work of passing through the rope between the electrodes in the strip treating apparatus prior to the start thereof, the strip is subjected to the plating treatment at a high current density. In case of passing through the weld-connected portion of the strips, which has a relatively large thickness, between the electrodes, the other electrode 2b is again moved to its opened position to pass through the above-mentioned weld-connected portion between the electrodes, and then, the plating treatment is carried out at a high current density in the same manner as mentioned above, if necessary. In the above-described embodiment, the manually operated levers can be substituted by automatically operating means. A rotary cylinder 20f for turning the cam shaft 20a is for example provided at the upper end of each of the cam shafts 20a as shown in Fig. 2. In this case, the rotary cylinder 20f is arranged above the surface of the bath in the bath tank 1, thus making it possible to prevent the rotary cylinder 20f having electric circuits being exposed to the treating solution such as a plating solution in the bath tank 1. Now, another embodiment of the strip treating apparatus will be described hereafter with reference to Fig. 3. In Fig. 3, the other electrode 2b is slidably arranged on the upper electrode-holders 3 so as to be openable and closable. A pneumatic cylinder 21f as the opening and closing mechanism is fixed to each of the upper electrode-holders 3. More specifically, the free end of the operating shaft 21a of each of the pneumatic cylinders 21f is secured to each of the both end portions of the upper bus bar 2c for the other electrode 2b. A vertical shaft21b is firmly connected to the middle portion of the operating shaft 21a of each of the pneumatic cylinders 21f. The lower end portion of each of the vertical shafts 21b is bent at right angles to form a horizontal portion 21c. The free end of the horizontal portion 21c of each of the vertical shafts 21b is secured to each of the both end portions of the lower bus bar 2c for the other electrode 2b. The above-mentioned pneumatic cylinders 21f serve as automatically operating means. Stopper portions 3b, 5b for limiting the sliding position of the other electrode 2b under the closed condition are provided on the upper and lower electrode-holders 3, 5, respectively. In the above-described construction, when the pneumatic cylinders 21f are operated to retract the operating shafts 21a thereof, the other electrode 2b slides on the upper electric-holders 3 so as to be in the opened position. In this stage, the force is directly transmitted to the upper and lower end portions of the other electrode 2b by the movement of the operating shafts 21a, since the operating shafts 21a are connected to the lower bus bar for the other electrode 2b through the vertical shafts 21b. This makes it possible to smoothly open and close the other electrode 2b without causing the undesirable swing of the electrode 2b, even when the upper electrode-holders 3 have a relatively large coefficient of friction with the result that there may be easily caused the undesirable swing of the electrode 2b during the sliding thereof. In the above-described embodiment, the frictional force on the sliding face can be further decreased. There is provided a sliding system as shown in Fig. 4, which comprises an LM guide member 22a secured on the upper electrode-holder 3 between the upper electrode-holder 3 and the upper bus bar 2c for the other electrode 2b; and a fitting member 22b secured to the upper bus bar 2c, into which the above-mentioned LM guide member 22a is fitted. The linear actuator 22c comprising the pneumatic cylinder is fixed to the upper electrode-holders 3, and the free end of the operating shaft 22d of the linear actuator 22c is secured to the upper bus bar 2c. Since the frictional force on the sliding face is small in the above-mentioned construction, the other electrode can be opened or closed by the operation of small-sized pneumatic cylinders. The other electrode can be moved without swinging, resulting in relief of the necessity of providing the vertical shafts for connecting the operating shafts 22d with the lower portions of the other electrode, thus simplifying the opening and closing mechanism. The preferred embodiment is applied to the plating apparatus in the above-described embodiment. The preferred embodiment can also be applied to the other strip treating apparatus, for example, a cleaning apparatus in which impurities adhered on the surface of the strip are electrolytically removed in an alkaline treating solution. In this case, the electrodes serve as a cathode.

Claims: An apparatus for treating a strip, wherein homopolar electrodes (2) are arranged so as to face to each other in a bath tank (1), and said strip is travelled between said electrodes (2) to subject said strip to any one of a plating treatment, a cleaning treatment and another treatment, wherein insulators (8) are provided so as to be projected on opposite surfaces of said electrodes (2), and each of said insulators (8) has a slant face inclined from a side of each of said electrodes (2) toward said strip in a travelling direction of said strip, characterised in that : one electrode (2a) of said homopolar electrodes is stationarily secured to said bath tank (1); and an opening and closing mechanism (20) for adjusting a distance between said electrodes (2) is provided at said other electrode (2b). An apparatus for treating a strip as claimed in claim 1, wherein said homopolar electrodes (2) are arranged vertically and all of the operating members of said opening and closing mechanism (20) are positioned above a surface of a bath in said bath tank (1). An apparatus for treating a strip as claimed in claim 1 or 2, wherein said opening and closing mechanism (20) comprises a pair of electrode holders (3,5) positioned on both end portions of said other electrode (2b), frame-shaped followers (20d) provided at the both end portions of said other electrode (2b), cam shafts (20a) rotatably supported on said electrode holders (3,5), cams (20b) secured to both end portions of said cam shafts (20a), and fitted into said frame-shaped followers (20d), and operating members provided at one end portions of said cam shafts (20a). An apparatus for treating a strip as claimed in claim 2, wherein said opening and closing mechanism (20) comprises a bus bar (2c) connected to an upper end of said other electrode (2b), upper electrode-holders (3) positioned on an upper end portion of said other electrode (2b), a sliding system for slidably supporting said bus bar (2c) on said upper electrode-holders (2b), and a linear actuator (22c) for sliding said bus bar (2c) on said sliding system.

Inventors: FUJII TADASHI, SUGIOKA EIICHIRO, FUJII, TADASHI, SUGIOKA, EIICHIRO, FUJII, Tadashi, Toyo Kohan Co., Ltd., SUGIOKA, Eiichiro, Toyo Kohan Co., Ltd.
Applicants: TOYO KOHAN CO LTD, TOYO KOHAN CO., LTD
Application year: 1995
Main classification: C25D7
IPC codes: C25F7, C25D7