Abstract:
A contacting device for a galvanization apparatus comprises contacting rollers with a continuous rigid external face, which is joined to a jacket section. The jacket section is provided with an inner opening that is wider than a rotating shaft on which the contacting roller sits. This allows the contacting roller to be moved in a radial direction, wherein electric contacting and securing of a basic position is obtained via springs in every one of the radially moved positions. The moveability of the contacting roller ensures good contact as the contacting roller rests against substrates also when the substrates are uneven. The contact pressure can be relatively small.

Description:
FIELD OF APPLICATION AND PRIOR ART  
       [0001]     The invention relates to a device for the treatment of substrates or flat articles, particularly a galvanizing device for substrates or for the coating of solar modules.  
         [0002]     DE-A-10323660 discloses a contact roller for the electrical contacting of substrates to be coated and contact zones are individually provided along the outer circumference thereof. Said zones are either movable or are elastically connected to a roller body, which is in particular made from flexible plastic, or elastically with the rotating shaft. This is in particular intended to engage the surface-extended contact zones as flat as possible on the substrates in order to bring about optimum contacting.  
         [0003]     It is also known for permanent contacting purposes, for example as a guard electrode to engage metal wheels or the like, which are continuous on the outside, as contacting means with substrates to be coated or treated.  
       PROBLEM AND SOLUTION  
       [0004]     The problem of the invention is to provide an aforementioned device or contacting means which can obviate the problems of the prior art and which in particular make it possible to keep low the pressure of the substrates exerted by the engagement of the contacting means, whilst ensuring the necessary contacting.  
         [0005]     This problem is solved by a device having the features of claim  1 . Advantageous and preferred developments of the invention form the subject matter of the further claims and are explained in greater detail hereinafter. By express reference the wording of the claims is made into part of the content of the description.  
         [0006]     The substrates run on a passage path through a treatment chamber, which contains a treatment medium, for example an electrolytic solution. For passage purposes conveying means are provided and they both support the substrates and convey them through the treatment chamber. In addition, there are contacting means with which by means of a conductor device there is an electrical contacting or power supply with the substrates. Said contacting means have a rigid or closed continuous surface or outside with which they engage on the substrates. They also have a substantially rigid carrier or support ring as a type of inside part, the aforementioned surface or outside being fitted to the support or carrier ring as a separate part or is integrally formed by the same. According to the invention the carrier ring has a continuous inner opening. The inside diameter of this inner opening exceeds the diameter of a shaft on which a contacting means is held or rests. There is also a flexible or continuous electrical contacting from the surface or outside with the conductor device. As a result of the larger inside diameter of the inner opening the carrier ring has a certain mobility on the shaft or can be moved away or evade substrates. Thus, the contacted substrates are protected or kept free from any mechanical stressing, such as is normally the result of the application of a contacting roller or the like. In order to bring past the contacting means any unevenness or thicker areas of the substrates whilst maintaining contacting, the contacting means are in their entirety moved away or deflected, whilst maintaining contacting. As a result of the additional flexible contacting of the surface or outside with the conductor device or a power supply or the like, despite the mobility of the contacting means on the shaft a reliable electrical contact occurs. In a further development of the invention it is possible for the power supply to take place via the shaft or at least via a portion of the shaft. This is for example an infeed on an outer end of the shaft with a tap in the vicinity of the contacting means.  
         [0007]     According to the invention the carrier ring need not be mounted directly on the shaft and instead can be placed on a thickening or an additional collar or the like. What is in fact important for the invention is that a carrier ring of the contacting means is located or held radially on the shaft, advantageously in a random radial direction. It need not necessarily be in direct contact with the shaft.  
         [0008]     The inside diameter of the inner opening of the contacting means or the carrier ring can be at least 5%, preferably approximately 10% larger than the shaft cross-section. Preferably the inner opening and shaft have a similar cross-section and in particular circular in each case.  
         [0009]     The carrier ring can be sleeve-like, collar-like or tubular with a certain length extension along the shaft. As a result of said length extension, apart from the greater inside diameter and therefore a somewhat looser seating, the carrier ring can be deflected away from the shaft, but cannot excessively strongly laterally tilt. As a measure for this it is for example possible to make the carrier ring longer than the diameter of the shaft or the inside diameter of its inner opening. From said sleeve-like or tubular part of the carrier ring can project radially a type of flange with the surface or outside. The flange projects advantageously centrally from the carrier ring. Particularly advantageously the surface or outside forms a widening or flattening of the projecting flange for increasing the contacting surface area on engagement with a substrate. If the contacting means is constructed in mirror symmetrical manner to a surface perpendicular to the shaft and passes through the centre of the outside, when resting on a substrate no tilting moment is exerted and there is a very uniform contacting.  
         [0010]     In a simple construction of the contacting means, the carrier ring is integrally manufactured together with the surface or outside, namely from the same material, preferably metal, such as for example copper. For this purpose either different parts can be assembled or the contacting means can be shaped from a single metal part.  
         [0011]     The flexible contacting on the surface or outside can be resilient or elastic. In particular, this compensates movements of the carrier ring or outside relative to the shaft, particularly if they are radial movements. It is also possible to influence these movements, which will be explained in greater detail hereinafter.  
         [0012]     In an advantageous development of the invention an elastic or resilient holding of the carrier ring on the shaft takes place. In a normal position the carrier ring can be seated roughly concentrically on the shaft and in particular the surface or outside is concentric to the shaft. If the carrier ring or contacting means is deflected from the normal position, particularly radially and away from the substrate, the resilient holding action builds up a force bringing about a return to the normal position. The normal position is such that in it the contacting means precisely contacts in the desired manner a moving past substrate. As a function of the desired use or desired guide-back force of the contacting means the magnitude of the resilience on the holder can be determined. It is for example also possible to implement the resilient holding together with the aforementioned flexible contacting or to carry out contacting by means of the resilient holder, i.e. both functions are combined in a single component.  
         [0013]     In a further development of the elastic holder, it is possible to construct it in such a way that the carrier ring can be moved in the longitudinal direction of the shaft out of the normal position by a small amount. Advantageously following the longitudinal movement through the resilient holder a guide-back force is built up, particularly through the same spring or same spring mechanism as for the guide-back following the radial movement. As a result the surface or outside and therefore the entire contacting means are mounted in movable manner on the shaft. As a result of the resilient holder they are brought out of their deflected position back into the normal position. Advantageously the resilience bringing about a return to the normal position is very small, so that in the case of an unevenness the contact pressure on the substrate to be contacted is limited and in this way for example in the case of sensitive solar modules made from thin glass damage can be avoided.  
         [0014]     Such a resilient holder can for example run in helical spring-like manner over a longitudinal area of the shaft. It can engage on the shaft laterally alongside the carrier means or can be connected thereto, for example by at least one closely engaging turn. In lateral extension towards the carrier ring the turns can become larger and can engage over an aforementioned collar-like or tubular section of the carrier ring in order to hold the same. Such a resilient holder can be provided on both sides of the carrier ring and can maintain the same in the normal position. As mentioned hereinbefore, they can also form the electrical contacting via a shaft on the carrier ring and therefore on the contacting means.  
         [0015]     It is advantageous that in the case of the inventive device the treatment medium only reaches the underside of the substrate. Thus, the top of the substrates can be kept free, which can be advantageous with respect to a contacting behaviour and also greatly reduces contamination. In conjunction therewith the contacting means engage on the top of the substrates, i.e. in the area free from the treatment medium. In particular, the contacting means only engage on the top side. If the contacting means do not come into contact with the treatment medium, it is possible to avoid the coating material being undesirably deposited on the contacting means. As a result it does not have to be removed in a complicated manner.  
         [0016]     In a further development of the invention it is possible to provide light sources in the treatment chamber below the substrates. Particularly when coating solar modules, this offers the advantage that through light action the coating process can be positively influenced, as is known to the expert from the prior art, for example from EP-A-542148. The light sources are elongated or in the form of tubes and optionally run transversely to the passage path.  
         [0017]     These and further features can be gathered from the claims, description and drawings and the individual features, both singly and in the form of subcombinations, can be implemented in an embodiment of the invention and in other fields and can represent independently protectable constructions for which protection is claimed here. The subdivision of the application into individual sections and the subheadings in no way restrict the general validity of the statements made thereunder. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     Embodiments of the invention are described in greater detail hereinafter relative to the attached diagrammatic drawings, wherein show:  
         [0019]      FIG. 1A  plan view of inventive contacting means on a shaft in the passage direction.  
         [0020]      FIG. 2 A  greatly enlarged representation of the contacting means of  FIG. 1 .  
         [0021]      FIG. 3 A  galvanizing device with said contacting means in side view. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0022]     Considered in the passage direction,  FIG. 1  is a plan view of the contacting rollers  20  constituting contacting means and which are mounted on a shaft  30  and rest on the top side of a substrate  16 , such as a solar module or a printed circuit board.  FIG. 1  shows that two juxtaposed contacting rollers  20  are arranged on shaft  30  for a substrate  16 , for example for a per se known better surface distribution of the electrical contacting. The electrical contacting on shaft  30 , which is made from metal or which is at least electrically conductive, takes place by means of the conductor device  21 . It is also possible to convey in juxtaposed manner several webs of substrates  16 , in certain circumstances whilst also adapting their format, so that different formats of substrates can be worked in precisely adapted manner. Thus, for the passage path there can be several juxtaposed conveying rollers, where the substrates are positioned precisely between said rollers. As a result they are secured against lateral displacement. The resting of the substrates on the conveying rollers can also be such that in this area the rollers have a conical construction, as can be gathered from  FIG. 1 . Thus, a centring and straight alignment of the substrates with the conveying rollers take place. The laterally projecting edge of the conveying rollers prevents a strong displacement of the substrates.  
         [0023]     The precise construction of the contacting rollers  20  is apparent from the much larger scale view of  FIG. 2 . A contacting roller  20  has a sleeve  22  constituting the aforementioned collar-like or tubular part. Said sleeve  22  has an inner opening  23  through which passes the shaft  30 . As the inside diameter of the inner opening  23  significantly exceeds that of the shaft  30 , the gap  29  is formed. Both inner opening  23  and shaft  30  are circular, so that the sleeve  22  can move the contacting roller  20  upwards or downwards by the size of the gap  29  in the case of unevenness on the substrate  16 , as will be explained hereinafter.  
         [0024]     A flange  24  projects roughly at right angles from the central area of sleeve  22 . It passes outwardly into outer ring  26  with a widened, flat outside  27 . As can be gathered from  FIG. 2 , the contacting roller  20  is here in one piece, for example of a metal such as copper. Through the length of the sleeve  22  an excessively strong tilting of contacting roller  20  on shaft  30  is prevented. As a result of the narrow or thin construction of sleeve  22 , flange  24  and outer ring  26 , whilst ensuring security against tilting and a wide contacting surface through outside  27 , a more lightweight construction can be achieved. This is particularly important, because the weight of contacting roller  30  plays a part in connection with the force with which it rests on the top of substrate  16 .  
         [0025]     Helical springs  32  engage over both ends of sleeve  22 . In each case the helical springs  32  rest directly on shaft  30  with a remote, narrow end  34 , advantageously accompanied by non-positive, frictional, immovable connection. This connection can be further improved by a groove in shaft  30 . Towards the contacting roller  20  or flange  24  the turns of helical springs  32  become broader and engage over the outer areas of sleeve  22 . As shown, the latter can be flattened on its outside in order to permit a continuous rise in the width of the turns of helical springs  32 . By means of a wide end  36  the turns of the helical springs  32  engage directly on sleeve  22 , very close to flange  24 . The turns of helical springs  32  at the wide end  36  can also be such that they rest in non-positive, frictional manner on sleeve  22 , in certain circumstances further improved by a milled in groove.  
         [0026]     The resilient holding of contact roller  20  on shaft  30  by helical springs  32  leads to the contacting roller in the case of an upward deflection, not only being applied to the substrates again in the downwards direction as a result of its weight, but also as a result of spring tension. This makes it possible to ensure that on the run-up to an edge of substrate  16 , the contact roller  20  does not jump upwards with a brief interruption of the electrical contacting and instead always remains pressed on. This pressure force is relatively limited in order to protect sensitive substrates. As a result of the resilient holder the contacting roller  20  is secured against longitudinal displacement, a certain mobility existing. However, following a deflection, the contacting roller  20  is always forced back by the helical springs  32  into the normal position shown in  FIG. 2 . In addition, the helical springs  32  also fulfil the function of electrically contacting the contacting roller  20  with shaft  30 , once again on conductor device  21  and power source  13 .  
         [0027]     If in the case of a similar contacting or galvanizing device a greater mobility of the contacting roller on shaft  30  is required, it would be possible to enlarge the inner opening  23  or gap  29 . It is also conceivable that in place of the outwardly engaging helical springs  32 , a spring mechanism could be placed in the inner opening  23 , for example with a radially resilient action and it could also be in the form of a very elastic foam or the like. Such a foam could be introduced as a further sleeve or hose-like article between shaft  30  and inner opening  23 . Electrical contacting then takes place for example either via a helical spring or an electrical conductivity of the foam or a freely connected conductor between contacting roller  20  and shaft  30  or conductor device  21 .  
         [0028]     Besides compensating a possible unevenness on the substrate  16 , the mobility of the contacting rollers  20  relative to shaft  30  also serves to raise the same by means of a displacement device  40 . The latter engages with a hook-like section from at least one side and preferably with two facing hooks from both sides, below the outer ring  26  and can bring about a forced raising of the contact roller  20  from substrate  16 . This can for example be used for removing undesired coatings of electrolytic solution  14  on outer ring  26  by reversing the polarity of power source  13 .  
         [0029]     The advantage of such a movably mounted contacting roller  20 , which is admittedly rigid and solid, but is movable or resilient with respect to the substrates, is that compared with the inherently flexible contacting rollers known from the prior art, the construction of the contacting roller here is much simpler. As will be apparent, a contacting roller  20  according to  FIG. 2  can be relatively easily rough worked or cast from a solid piece. In particular, the contacting roller has no movable parts. There is also no particular problem encountered when manufacturing the helical springs  32  and this also applies to the fitting of the two parts on shafts  30 . The contacting rollers as wearing parts must be frequently replaced, quite independently of their construction, so that a simple, inexpensive manufacture of said rollers is very important.  
         [0030]      FIG. 3  illustrates the installation procedure of a complete galvanizing device  11 . It has a treatment chamber  12  with power source  13 , which on the one hand is connected to electrodes  15  in electrolytic solution  14  in treatment chamber  12  and on the other to conductor device  21 . Conveying rollers  18  are placed in known manner at the bottom of treatment chamber  12  and on the same engage substrates  16  and are conveyed therewith. Contacting rollers  20  engage on the top of substrates  16 . As can be gathered from both  FIGS. 1 and 3 , the shafts  30  engage via driving wheels  38  on conveying rollers  18  and by means of the same are also rotated or driven. As the substrates  16  run precisely between the shafts of conveying rollers on the one hand and shafts  30  of contacting rollers  20  on the other, conveying rollers  18  and contacting rollers  20  rotate at the same speed. As a result it is possible for only the shafts of conveying rollers  18  to be driven.  
         [0031]     Moreover, light tubes  42  are placed below substrates  26 , namely between the electrodes  15  in each case. There can also be light sources over substrates  16 . These light tubes emit with radiation or emission areas indicated in dot-dash line manner the underside of substrate  16 , which in this case are advantageously PV or solar modules. As a result the galvanizing action can be improved by self-generation of the galvanizing current, such as is for example known from EP-A-542148. The intensity of the light sources can be controlled in order to influence the deposition rates on the solar modules. The wavelength can be between 400 nm and 1100 nm. The light sources can as an alternative to light tubes also be individual emitters, for example in punctiform or rectangular form. To intensify the action reflectors can also be provided. The light tubes can also be equipped for immersion.  
         [0032]      FIG. 1  more particularly shows how the substrates  16  run entirely below the level of electrolytic solution  14 , i.e. are completely immersed. Thus, also the outer rings  26  of contacting rollers  20  run in electrolytic solution  14 . In another development of the invention the electrolytic solution level can be lower, for example at the level  14 ′ shown in broken line form, so that the underside only of substrates  16  is wetted. As a result the top of substrates  16  can remain dry and therefore the contacting rollers  20  or their outer rings  26  are free from electrolytic solution.  
         [0033]     Besides an advantageous use of contacting rollers  20  for electrical connection to power source  13  for galvanizing substrates  16 , said rollers can also be used to apply a protective potential to the substrates, for example to solar modules, which as substrates  16  run through the plant. A guard electrode can be constructed as a sacrificial anode. This also prevents corrosion, so that no power source is connected here. On the back of the solar modules is provided an aluminium coating. If said aluminium coating is contacted via contacting rollers  20  and via conductor device  21  a protective potential is applied, the dissolving of the aluminium can be prevented. In this case, the above-described generation of the galvanizing current by the light tubes  42  can be particularly advantageous.  
         [0034]     In addition, guard anodes can be provided, which can be positioned in spaced manner with respect to the cathodes or electrodes  15  and parallel thereto. They can have a soluble or insoluble construction. A protective potential can be applied by means of said guard anodes and in certain circumstances also by means of contacting rollers  20 . This can take place in the stripping operation, i.e. when undesired coatings are removed by reversing the polarity. This in particular makes it possible to remove undesired coatings from the contacting rollers  20  and here the substrates can be used as counterelectrodes. When the contacting rollers are in a raised position it is possible to use them as guard anodes. For a continuous, uninterrupted coating operation a contacting roller should always engage on a substrate. Thus, the contacting rollers can for example be raised in alternating manner for removing the coating and lowered for contacting the substrates.  
         [0035]     The application of the protective potential can take place overall and also locally in an adjustable, regulated or controller manner, which can take place by means of one or more rectifiers. In certain circumstances this can also apply to groups of contacting rollers or even individual contacting rollers, so that a removal of coatings can be carried out in planned manner, especially on individual contacting rollers. As a result other contacting rollers can continue to fulfil the contacting function.