Title of Invention	DEVICE AND METHOD FOR SURFACE TREATMENT OF PARTS
Abstract	The invention proposes a device and a method for surface treatment of parts by dipping processes, having treating stations (15) for treatment of the parts (42, 42') by a dipping process, conveyor means (92) for transport of the parts, which extends outside the treating stations (15) and along which can be moved a plurality of carrying elements each provided with a holding fixture (40) for fixing at least one of the parts to be treated, each of the parts (42, 42') being mounted on the holding fixture (40) for pivotal movement about a horizontal pivot axis (100) in a position outside the treating station (15) from where it can be moved into and withdrawn from the treating station (15) by a slewing movement.

Title of Invention

DEVICE AND METHOD FOR SURFACE TREATMENT OF PARTS

Abstract

The invention proposes a device and a method for surface treatment of parts by dipping processes, having treating stations (15) for treatment of the parts (42, 42') by a dipping process, conveyor means (92) for transport of the parts, which extends outside the treating stations (15) and along which can be moved a plurality of carrying elements each provided with a holding fixture (40) for fixing at least one of the parts to be treated, each of the parts (42, 42') being mounted on the holding fixture (40) for pivotal movement about a horizontal pivot axis (100) in a position outside the treating station (15) from where it can be moved into and withdrawn from the treating station (15) by a slewing movement.

Full Text	1 DEVICE AND METHOD FOR SURFACE TREATMENT OF PARTS The present invention relates to a device for surface treatment of parts having treating stations, especially treating baths, for treating the parts comprising conveyor means for transport of the parts along which is movably guided at least one carrying element provided with a holding fixture for fixing at least one of the parts to be treated, the holding fixture being pivotally supported on a slewing device with a substantially horizontal pivot axis, the arrangement being such that movement of the carrying element causes the parts to be moved along the conveyor means into an operating position above or below a treating station, the carrying element being configured so that the parts can be swung into and out of the treating station in their working position above or below a treating station. 2 The invention further relates to a method for the surface treatment of parts in treating stations, wherein the parts are mounted on a holding fixture pivotally supported on a carrying element that can be displaced along conveyor means, whereby during movement of the carrying elements the parts are moved to the treating stations along the conveyor means, are positioned above or below the latter, and are swung into and out of the treating stations by a slewing movement about a substantially horizontal pivot axis. The term "surface treatment of parts" as used in the present application is meant to describe any chemical and/or physical treatment of parts, including any chemical pre-treatment, such as, for example, ungreasing, washing, activating, zinc phosphating operations, etc. Alternatively, or in addition to this interpretation, the term "surface treatment of parts" is intended to include also a coating process or some surface treatment of the parts as such, including for example a dip-coating process. A device and a method of the before-mentioned kind have been known from DE-A-200 22 634. In this case, guide means are provided in the area of the treating stations for guiding the movement of bogies each of which is provided with a rotatable support for a vehicle body, the arrangement being such that the vehicle body can be moved into and out of the treating station by rotation about an axis of rotation. Each of the bogies is provided in this case with a separate drive and can be moved independently one from the other. 3 Although such a design permits the transport of the parts between the treating stations to be realized in a relatively simple way, and facilitates movement of the parts into and out of a treating station, such a device and such a method frequently cannot guarantee the quality demands placed on the quality of the finished surface that have become more stringent lately. Now, it is the object of the present invention to provide a device and a method for the surface treatment of parts at the highest possible quality whereby the least possible amount of defects on the finished surface, for example the coated surface, can be achieved. At the same time, the invention is intended to provide a structure with the highest possible reliability and cost-saving effect. This object is achieved, by a device of the kind described above, in that a holding fixture is pivotally mounted on pivot bearings which, in a working position in which a part is to be swung into or out of a treating station, is positioned laterally outside the treating station. With respect to the method, the object is achieved by a method of the before-mentioned kind in that during the slewing movement into and out of the treating station, the parts are held, and are preferably driven, laterally outside of one of the treating stations. The object of the invention is thus perfectly achieved. 4 Given the fact that according to the invention the holding fixture intended to mount the parts in a working position, for being swung into and out of a treating station, is arranged laterally outside the treating station, contamination of, for example, treating baths by lubricant or the like leaking from the pivot bearings is prevented. The possibility of foreign particles being introduced into the treating stations is thereby reduced to a minimum. The statement that the pivot bearings are arranged "laterally outside the treating station" is intended to mean in the context of the present invention that the pivot bearings are offset relative to the treating station far enough to ensure that contamination of the treating station by contaminants from the pivot bearings is avoided. If, for example, the treating station is a treating bath this means that the pivot bearings must not be arranged vertically above the surface defined by the treating bath, but must be offset laterally to the outside. When the treating station is protected from the outside by a housing, the pivot bearings may be provided inside the housing, but in a position laterally offset from the surface defined by the treating bath. Further, the invention ensures by a suitable arrangement and configuration of the conveyor means and carrying elements that the parts to be treated can be swung into and out of a treating station by a slewing movement. This guarantees an especially simple and cost-saving process flow. The conveyor means extends in this case preferably laterally beside the treating stations or, alternatively, above or below 5 the treating stations. In cases where the conveyor means is arranged laterally beside the treating stations a cantilever arm, projecting horizontally in the direction of a treating station, enables a part to be positioned in a working position above or below a treating station where a single slewing movement is required to swing the part into or out of the treating stations. When the conveyor means is arranged above the treating stations, at least in part, the carrying elements are suspended on the conveyor means and can preferably be displaced along the conveyor means by a separate drive. According to a preferred further development of the invention the conveyor means extends outside the treating station. Such an arrangement, in which the conveyor means is arranged laterally offset from the treating station, prevents contamination of the treating station by contaminants that may leak out from the conveyor means. In this connection, the conveyor means may further be separated from the treating station by a wall. According to an advantageous further development of the invention, the slewing device comprises a slewing drive located laterally outside the corresponding treating station in its working position. This also prevents contamination of the treating station by the slewing drive. 6 According to a further advantageous embodiment of the invention, the carrying element comprises a cantilever arm, projecting from it in horizontal direction, on which is provided the holding fixture which can be positioned above of below a treating station. This permits the conveyor means for the respective carrying elements to be provided completely laterally outside the treating stations. Transferring the parts into the working position, for being swung into a treating station, is rendered possible in this case by the cantilever arm projecting in horizontal direction. The conveyor means being thus arranged completely laterally outside the treating stations, it is easily accessible for maintenance and repair work. In cases where the treating station is separated from the conveyor means by a wall, the cantilever arm preferably extends through a slot provided in the wall. This minimizes any contamination of the parts during surface treatment thereof. According to a further development of the invention, there is provided a control device, which is coupled at least with the conveyor means and the slewing devices for controlling the movement of parts to be treated. This permits optimum treatment of the parts in the treating stations to be achieved. 7 The slewing device permits movements into and out of the working position to be realized at any desired angle. This considerably reduces any inclusion of air during the dipping process so that coating defects are avoided. The slewing movement can be effected also during the treating and/or coating time within the treating station, whereby a more intensive flow around the part being treated can be achieved. Due to the relative movement of the part, this also allows any air bubbles, that may still be present, to migrate so that all surfaces can be pretreated and/or coated in the best possible way. Depending on the particular design of the slewing device and the cantilever arm on which it is received, a slewing movement of up to 180° or even a slewing movement over full 360° or more can be realized. This permits the parts to be moved into a treating station, and to be later removed from it, by a single slewing movement without the need for additional lifting means. It is, thus, possible to swing the parts from a horizontal position into an overhead position in a treating station. This permits surfaces, that need to be pre-treated and coated at high quality, to be positioned in the treating station with the face down, whereby any contamination by deposition of particles on such surfaces in the treating baths is excluded. Further, a slewing movement permits optimum draining off of the parts to be dipped so that entrainment of bath liquid, for example between different treating baths, is minimized. Even more complex, scoop-type parts can be coated in this way free from defects. In addition, the sequence of the dipping and/or lifting operations can be adapted in this way to the geometry, stability and the dripping behavior of a vehicle body, for 8 example. For example, a part can be stopped for a given time in vertical position in order to improve the dripping process. According to a further advantageous embodiment of the invention, each carrying element comprises a drive for displacement along a guide of the conveyor means. One thereby achieves the greatest possible flexibility for the movement of the different carrying elements and, thus, the parts to be treated. Even a limited return motion is rendered possible. This is advantageous in particular for smaller systems . For example, it is possible to use a single washing bath after two different processes, such as an ungreasing and a phosphating process, by moving the part from the phosphating bath back to the washing bath. This allows an especially compact structure for smaller throughputs. In this case, the slewing device preferably comprises a slewing drive, which is supplied with energy via the conveyor means. Preferably, this is effected by supplying the slewing drive with energy via a carriage mounted for displacement along a guide of the conveyor means. One avoids in this way the use of trailing cables, which otherwise would be required for the energy supply of the slewing drives. According to a further advantageous development of the invention, the conveyor means is configured as a telpher line system. 9 As is generally known, telpher line systems comprise a carrying and guide element for example in the form of an I section. The carrying and guide element is further provided with integrated current busbars by means of which vehicles guided on a carriage can be supplied with energy. Further, such busbars serve to exchange control signals so that the vehicles can be driven independently and can be displaced in a controlled way. Preferably, the different vehicles are equipped in this case with a separate small SPS control system. Such a conveyor arrangement permits especially flexible production processes to be guaranteed for the surface treatment of parts. A highly flexible process flow can be guaranteed especially in combination with a central host computer coupled with the separate control systems of the vehicles. In an advantageous further development of the invention, the holding fixture comprises a preferably U-shaped, H-shaped or rectangular slewing frame mounted on pivot pins, on which mounting elements for mounting the part to be treated are received. This ensures an especially simple structure of the holding fixture, suited for a swinging motion for swinging parts into and out of the respective working position. An especially favorable dripping behavior is achieved, in particular, with a Ushaped frame. Preferably, the slewing frame as such is located outside of the dripping area of the part to be treated, for which purpose inwardly projecting brackets or tongues, on which 10 struts holding the parts are arranged, may be provided on the slewing frame. This minimizes any contamination. According to another embodiment of the invention, a plurality of carrying elements is driven by means of a circulating conveyor. This provides an especially cost-saving way of driving the conveyor means. The carrying elements are driven in this case either jointly by one trailing drive, or preferably independently. According to an additional further development of the invention, a lifting device is provided on the at least one carrying element, by means of which the cantilever arm is received on the carrying element for displacement in vertical direction. This permits a lifting movement to be carried out in addition to the slewing movement, whereby optimum treatment is rendered possible. The slewing movement and the lifting movement can be adapted in this case to the particular structure of the parts to be treated so as to achieve an especially favorable dipping behavior, minimization of the formation of air bubbles during treatment, an especially uniform treatment and best possible draining off when the part is removed from a treating bath. In an additional further development of the invention, the conveyor means is configured as a circulating conveyor one working section of which extends along the side faces of the treating stations in a first direction (X direction), while the return section is guided back at a distance from the treating 11 stations, with head sections formed between the working section and the return section that comprise a transfer position, for allowing the parts to be treated to be taken over at one of the head sections, and a takeover position allowing the parts to be treated to be discharged at the other head section. There is also the possibility to use the different head sections for both the takeover and the discharge of parts. One thus achieves an especially compact and cost-effective overall arrangement. For, a circulating conveyor is in a position to run around all treating stations. The cornering movements in the transition area between the working section and/or the return section and the head sections permit the parts conveyed, which as a rule contact the respective sections in lengthwise direction, to be directly taken over in that position at the transfer position by the holding fixture of a slewing device, and, during the next following cornering movement, to be brought to the correct position in which it can be dipped into a treating bath, for example, by a corresponding slewing and/or lifting movement. Correspondingly, it is also possible to discharge the treated parts at the opposite head section of the circulating conveyor in the transfer position, either in a first direction (X direction) or in a direction perpendicular thereto, in order to convey the parts to a subsequent process, for example to a baking system. This avoids the need for additional conveyor means, such as turntables or the like. Basically, there is of course also the possibility to arrange the transfer operation along the longitudinal sections. According to an additional further development of the invention, at least one of the treating stations is configured as a 12 spray tunnel or a washing tunnel. In this case, the treating station is preferably provided with cover plates that can be moved together above the treating station. This then even permits a spray treatment to be carried out. Preferably, the cover plates are provided with longitudinal slots for the forward and return movement of the carrying elements, and with transverse slots that permit the carrying element to be slightly pivoted about a pivot axis extending in the conveying direction. It is possible in this way to perform a movement during the spray pre-treatment in order to achieve a uniform spray pattern. According to a further development of the invention, at least one of the treating stations is configured as a drying station, baking stove, inspection room, cooling station, bonding station or underbody coating station. This permits the use of the conveyor means to guarantee full transport of the parts not only through the pre-treating stations, but also through other stations, such as a dip-coating system. This avoids the need for transfer operations, which improves the quality of the surfaces produced. In the case of stations enclosed by a housing, a lead-in opening enabling a carrying element to be swung into the housing is provided for this purpose, preferably in the bottom or in the cover, which opening is connected, via a slot extending in the 13 direction of the conveyor means, with a Lead-out opening enabling the carrying element to be swung out of the housing. This permits a part, which is received on a carrying element, to be swung into the housing at the beginning of the housing, to be transported therein in vertical position, and to be swung out of the housing at the end of the treatment. As this permits the parts to be transported, for example, in upright position during treatment, for example in a dryer, one thereby obtains surfaces of especially high quality. It is understood that the features of the invention mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention. Certain preferred embodiments of the invention will be described hereafter with reference to the drawings in which: Fig. 1 shows a diagrammatic, largely simplified overall top view of a device according to the invention; Fig. 2 shows a largely simplified cross-section through the device according to the invention, taken in a plane perpendicular to the first direction (main transport direction); Fig. 3 shows a modification of the embodiment illustrated in Fig. 2; 14 Fig. 4 shows another modification of the invention, represented in a simplified front view, of a holding fixture for a part to be treated; Fig. 5 shows a side view of the carrying element and the holding fixture of an embodiment slightly modified by comparison with Fig. 1; Fig. 6 shows another modification of the invention, represented by a simplified top view, of a carrying element with cantilever arm; Fig. 7 shows an enlarged section of a device according to the invention, as shown in Fig. 4; Fig. 8 shows another modification of the embodiment of Fig. 4, where the treating station is configured as a spray tunnel; Fig. 9 shows a top view of the cover plates of the spray tunnel according to Fig. 8; Fig. 10 shows another modification of the invention, where the holding fixture with the parts received on it can be transported through a slot in the bottom of the treating station in upright position; and Fig. 11 shows a simplified bottom view of the device according to Fig. 10. 15 Fig. 1 shows a largely simplified top view of a device according to the invention for the surface treatment of parts, indicated generally by reference numeral 10. The device 10 comprises a plurality of treating stations in the form of treating baths 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 of rectangular outline, having their long sides arranged one adjacent the other, so that their short sides extend in a first direction (X direction). The treating baths 12-21 may for example include baths for dip-ungreasing, dip-washing, activation, zinc phosphating, dip-washing in fully desalinated water, dipcoating, and the like. A plurality of carrying elements 36, of which only four elements 36, 36', 36', 36'', intended to transport the parts through the device 10 and to dip and remove the parts into and from the treating baths 12-21, are shown by way of example, are illustrated in different positions. Each of the carrying elements 36 comprises a cantilever arm 41 that projects in a substantially horizontal direction. The outer end of each cantilever arm 41 carries a slewing arrangement, indicated generally by 37, by means of which a holding fixture 40 for parts 42 to be treated can be swung about a pivot axis 38, as indicated diagrammatically by double arrow 39 near the slewing device 37. Parts 42 to be treated, which may for example consist of vehicle bodies (body shells), are each mounted on the holding fixture 40 of a slewing device 37, are moved to the respective treating baths 12-21 by corresponding movements of the carrying elements 36, are dipped into and removed from the baths by operation of the slewing device 37, and are finally caused to leave the last treating bath 21 before they can be transferred 16 to a subsequent system at a position indicated by reference numeral 42'. The transport of the carrying element 36 is effected by conveyor means 22, indicated generally by reference numeral 22, which takes the form of a circulating conveyor that may be driven by a trailing drive or may comprise individually driven, separately displaceable carrying elements 36. The conveyor means 22 comprises a working section 24, extending along the short sides of the treating baths 12-21 in a first direction (X direction), a return section 26, extending in parallel to and at a distance from the working section 24, for the return movement of the carrying elements, a first head section 2 8 and a second head section 30. In the area of the first head section 28, the carrying element 36 with its holding fixture 40 occupies a transfer position 32 in which the parts 42 to be treated can be conveyed from a preceding production station in the direction indicated by arrow 43 in a first direction (X direction) and can be fixed on the holding fixture 40. As a result of the movement along the conveyor means 22 out of the transfer position 32 in the direction indicated by arrow 44, a part 42 having been taken over in the transfer position 32 is now pivoted by 90°, whereafter it arrives at the treating baths 12-21 along which it is transported in the X direction, as indicated by arrow 45. Once it has left the last treating bath 21, the carrying elements are once more pivoted by 90°, as indicated by arrow 46, at the transition from the working section 24 to the second head section 30. This leads to a transfer position 34 at the second head section 30 in which parts 42 ' , that have been treated, can be either withdrawn in the X direc- 17 tion or displaced laterally in the Y direction, perpendicular to the X direction, as indicated by arrow 47, for being transferred to a subsequent production station, for example a baking installation. The structure of the carrying elements, together with the slewing arrangements, will now be described in more detail with reference to Figs. 2 to 4. In Fig. 2, a treating bath 15 can be seen with a carrying element 36 arranged in front of its end face. The carrying element 36 is received on a guide 52 of the conveyor means 42, shown diagrammatically only, which is separated from the space in which a treating bath 15 is enclosed by a wall 53. The carrying element 36 comprises a cantilever arm 41, projecting in a di rection toward the treating bath 15, so that a slewing device 37 carried at the end of a cantilever arm 41 has its pivot axis 38 located centrally above the treating bath 15. The cantilever arm passes through a slot 55 extending in the wall 53 in the direction of extension of the conveyor means 22. Mounted on the slewing device 37 is a holding fixture 40 in which a part 42 to be treated is fixed. In the position illustrated in Fig. 2, the part 42 to be treated can now be pivoted in downward direction by a slewing movement about the pivot axis 3 8 in the direction of double arrow 51, until the part 42 to be treated is completely submerged in the treating bath 15. The slewing process may also be continued during the treating time in order to achieve uniform treatment and to remove as far as possible any air bubbles that may adhere to the surfaces. At the end of the treatment, the part 42 is removed from the treating bath 15 by the reverse motion sequence and can then be transported on by 18 operation of the conveyor means 22 or of an independent drive of the carrying element 36. Other carrying elements 36' with a cantilever arm 41', a slewing device 37, which can be swung about the pivot axis 38', and a holding fixture 40' is shown in the right half of Fig. 2, in the area of the return section 26 of the conveyor means and, thus, during its return movement in the direction toward the transfer position 32 of the conveyor means. A slightly modified embodiment is shown in Fig. 3 and indicated generally by reference numeral 60. In this and the following figures, corresponding parts are indicated by corresponding reference numerals. The essential difference to the embodiment discussed with reference to Fig. 2 consists in that in this case, instead of being mounted directly on the respective carrying element 36, the cantilever arm 41 is mounted on a lifting arrangement 48 mounted on the carrying element 36 to move vertically (in the 2 direction) in the direction indicated by double arrow 4 9. The carrying element 36 is again firmly mounted on a guide 54 of the conveyor means 22, but is located in the space in which the treating bath 15 is put up, though at a lateral distance therefrom. The slewing device 37 mounted at the outer end of the cantilever arm 41 by means of which the holding fixture 40 for a part 42 can be swung in the direction indicated by arrow 50 can be additionally lifted or lowered in the direction of arrow 49. 19 It is understood that the slewing movement about the pivot axis 38 and the lifting movement in the direction of arrow 49 can be jointly controlled in this case by a central control 56, for example a SPS control, in order to thereby realize optimum conditions for the dripping and removal motions and, if desired, predetermined motion curves during the time of treatment. This permits surface treatments of especially high quality to be achieved depending on the nature of the respective parts to be treated. An embodiment of the device according to the invention, that has been slightly modified by comparison with the embodiment illustrated in Fig. 2, is illustrated in Fig. 4 and indicated generally by reference numeral 70. The holding fixture 40 intended to receive a part 40 to be treated is mounted on the carrying arm 41 of the carrying element 36. The holding fixture 40 comprises a substantially U-shaped slewing frame 97 on which four struts 98 are provided in the illustrated arrangement, the outer ends of which carry a part 42 to be treated, for example a body shell, which is fixed on it by mounting elements 99 (such as clamps). Laterally, the slewing frame 97 is pivotally seated on pivot pins 100 in pivot bearings 101. The pivot bearings 101 are mounted on the cantilever arm 41. The pivot bearings 101 are located a sufficient distance laterally outside the treating bath 15 provided underneath so that the vertical downward projection from the pivot bearings 101 comes to lie outside the treating bath 15. Any contaminants that may leak out from the pivot bearings 101 are thereby prevented from getting into the treating bath 15. Further, the chain wheels 20 (or alternatively rollers) of two pivot drives 102, 103 (not shown), by means of which the pivot pins 100 can be pivoted via a chain or a toothed belt 106, are indicated at the outer ends of the pivot pins 100 in Fig. 4. The arrangement of the slewing frame 97 preferably is such that the slewing frame 97 as such is already located outside the dripping area of the part 4 2. Only four brackets or tongues 118, that carry the struts 98 and that project inwardly from the slewing frame 97, are located in the dripping area. This minimizes both contamination and entrainment of the baths. Generally, seating the elements and their drive laterally outside the treating bath 15 located underneath guarantees that no contaminants from a seating or driving system for the slewing arrangement can get into the treating bath 15. The position of a part that has been pivoted in downward direction and into the treating bath 15 is indicated by the broken line 42 '. Fig. 5 shows an embodiment slightly modified by comparison with the embodiment according to Fig. 4, which is indicated generally by reference numeral 90. In this case, the cantilever arm 41 is arranged in the same plane as the pivot bearings and the pivot drive 103. This permits the conveyor means with the carrying element 36 to be separated by a wall 53 from the space in which the treating bath 15 is set up. The pivot drive 103 is driven by a chain or a belt 106 that extends through a slot 55 in the wall 53, in the same plane as the cantilever arm 41. All drive elements are, thus, separated by the wall 53 from the space in which the treating bath is set up, being connected 21 with it merely via a thin slot 55. The carrying elements 36 may be driven, by rollers and associated drive motors (not shown), for independent displacement on a guide 52 provided below them. Another modification of the device according to the invention is illustrated in Fig. 6 and indicated generally by reference numeral 110. Here again, the bearing and drive systems of the slewing frame 97 are configured in such a way that a treating bath 15 located underneath cannot be contaminated by contaminants issuing from them. Again, a cantilever arm 41 is mounted on the carrying element 36 and projects through the slot in the wall 53 in horizontal direction relative to the treating bath 15. A slewing frame 97 of substantially U-shaped configuration is pivotally mounted on the outwardly projecting free ends of the likewise substantially U-shaped cantilever arm 41. On the slewing frame 97, there can be seen four struts 98 serving to connect the frame with a part 42 indicated in broken lines. As has been discussed before in connection with Fig. 4, the slewing frame 97 is received on pivot pins 100 in pivot bearings 101 seated on the free ends of the cantilever arm 41. Two drive motors 111, indicated on the carrying element 36, are coupled via a shaft 109 for driving toothed belt drives 102, 103 via drive pulleys 110, 111. Further, two drive motors 112, 113 ensuring the movement along the guide 32, and a support roller 114 intended to support the 22 carrying element 36 at its upper end on the wall 53 can be seen on the carrying element 36. Fig. 7 shows an enlarged detail of Fig. 4. As can be clearly seen in Fig. 7, the brackets 118 project inwardly a sufficient length to provide a vertical distance d between the outer edge of the mounted part 42 and the slewing frame 97. The slewing frame 97 as such is, therefore, already located clearly outside the dripping area, as indicated by the distance d between the lateral edge of the part 42 and the slewing frame 97. Optionally, additional small nozzles may be provided on the slewing frame 97 to provide the possibility to shortly rinse the parts, which may have been contaminated by the bath liquid, above the bath before they are transported to the next bath. Another modification of the device according to the invention is illustrated in Figs. 8 and 9 and is indicated generally by reference numeral 140. In this case, the treating station takes the form of a spray tunnel 141. The spray tunnel 141 is closed off on its upside by two cover plates 146, 147, which can be laterally closed, for moving the parts in and out, as indicated by arrows 148, 149. Once a part has been moved into the spray tunnel 141, the cover plates 146, 147 are closed and the spray treatment can begin. As can be seen in Fig. 9, slots 150, 151 may be provided in the cover plates 14 6, 147, which altogether provide two H-shaped openings and which during the spraying treatment permit both a forward and backward movement and a slight slewing movement so that a uniform spay pattern can be achieved. There can be further seen in Fig. 8 the reservoir 143 in which the treating 23 liquid is collected and from which the treating liquid is supplied to the numerous spray nozzles 142 by a pump 144. A further embodiment of the invention is illustrated in Figs. 10 and 11 and is generally indicated by reference numeral 160. This embodiment is modified relative to Figs. 8 or 9 in that it shows a treating station 162, for example in the form of a dryer for a KTL baking process, through which the parts 42 can be moved in upright condition. This means that during treatment the parts 4 2 are held on the slewing frame 97 from below. Conveying the part 42 in upright position through the housing 164 is rendered possible by a longitudinal slot 166 in the bottom 165 of the housing 164 enclosing the dryer 162. It can be seen in Fig. 11 that a lead-in opening is provided in the bottom 165 on the inlet side of the housing 164, which permits a carrying element 36 with a part 4 2 mounted thereon to be pivoted into an upright position from below. This position is then followed, for example, by three treating positions inside the housing 164, as indicated by broken lines. At the outlet end of the dryer 162, there is correspondingly provided a lead-out opening 170 through which the carrying element 36 with a part 42 mounted thereon can be removed by a downward pivoting movement. 24 A device for surface treatment of parts having treating stations (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 141, 162), in particular, treating baths, for treatment of the parts (42, 92) , comprising a conveyor means (22, 92) for transport of the parts along which is movably guided at least one carrying element (36) provided with a holding fixture (40) for fixing at least one of the parts (42) to be treated, the holding fixture being pivotally supported on a slewing device (37) with a substantially horizontal pivot axis (38), the arrangement being such that movement of the carrying element (36) causes the parts (42, 92) to be moved along the conveyor means (22, 92) into a working position above or below a treating station (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 141, 162), the carrying element (36) and the holding fixture (40) being configured so that the parts (42, 92} can be swung into and out of the treating station (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 141, 162) ' in their working position above or below a treating station, characterized in that the holding fixture (40) is pivotally mounted on pivot bearings (101) which, in a working position in which a part is to be swung into or out of a treating station, is positioned laterally outside the treating station (12-21, 141, 162). The device as defined in claim 1, characterized in that the conveyor means (22) along which the at least one carrying element (36) can be moved, extends outside the treating stations (12-21, 141, 162 ). 25 3. The device as defined in claim 2, characterized in that the conveyor means (22) is separated from the treating station (15) by a wall (53). 4. The device as defined in claim 1, claim 2 or claim 3, characterized in that the carrying element (36) comprises a cantilever arm (41), projecting from it in horizontal direction, on which is provided the holding fixture (40) which can be positioned above of below a treating station (12-21, 141, 162). 5. The device as defined in claim 4, characterized in that the cantilever arm (41) extends through a slot (55) in a wall (53) which separates the conveyor means (22) from the treating stations (12-21, 141, 162). 6. The device as defined in any of the preceding claims, characterized in that the slewing device (37) comprises a slewing drive (102) which in the working position is located laterally outside the corresponding treating station (12-21, 141, 162), being preferably separated therefrom by a wall (53). 7. The device as defined in any of the preceding claims, characterized in that each carrying element (36) comprises at least one drive (112, 113) for displacement along a guide (52) of the conveyor means (22). 8. The device as defined in any of the preceding claims, characterized in that the holding fixture (40) comprises a preferably U-shaped, H-shaped or rectangular slewing frame 26 (97) mounted on pivot pins (100), on which mounting elements (99) for mounting a part (42) to be treated are received. 9. The device as defined in claim 8, characterized in that the slewing frame (97) can be pivoted by more than 180°, preferably by 360°. 10. The device as defined in any of the preceding claims, characterized by a lifting device (48) by which the holding fixture (40) is mounted on the carrying element (36) for displacement in vertical direction. 11. The device as defined in any of the preceding claims, characterized by a control device (56) which is coupled at least with the conveyor means (22) and the slewing device (37) for controlling the movement of parts (42) to be treated. 12. The device as defined in any of the preceding claims, characterized in that a plurality of carrying elements (36) is driven along a circulating conveyor (22). 13. The device as defined in claim 12, characterized in that the conveyor means (22) is configured as a circulating conveyor one working section (24) of which extends along side faces of the treating stations (12-21) in a first direction (X direction), while a return section (26) is guided back at a distance from the treating stations (1221, 71), with head sections (28, 30) formed between the working section (24) and the return section (26) that com- 27 prise a transfer position (32) , for allowing parts (42) to be treated to be taken over at one (30) of the head sections (30, 32), and a takeover position (34) allowing parts (42) to be treated to be discharged at the other head section (32) . 14. The device as defined in any of the preceding claims, characterized in that the slewing device (37) comprises a slewing drive (102, 103) which is supplied with energy via the conveyor means (22). 15. The device as defined in claims 1 to 11, 13 or 14, characterized in that the conveyor means is configured as telpher line system. 16. The device as defined in any of the preceding claims, characterized in that at least one of the treating stations (141) is configured as a spray tunnel or a washing tunnel. 17. The device'1 as defined in claim 16, characterized in that the treating station (141) is provided with cover plates (146, 147) that can be moved together above the treating station (141). 18. The device as defined in claim 17, characterized in that the cover plates (146, 147) are provided with longitudinal slots (150) for the forward and return movement of the carrying elements (36) , and preferably with transverse slots (151) that permit the carrying elements (36) to be 28 slightly pivoted about a pivot axis extending in the conveying direction (22). 19. The device as defined in any of the preceding claims, characterized in that at least one of the treating stations (162) is configured as a drying station, baking stove, inspection room, cooling station, bonding station or underbody coating station. 20. The device as defined in claim 19, characterized in that the at least one treating station (162) is enclosed by a housing (164) the bottom or cover of which comprises a lead-in opening (168) for permitting the carrying element (36) to swung into the housing (164), which opening is connected, via a slot (166) extending in the direction of the conveyor means (22), with a lead-out opening (170) enabling the carrying element (36) to be swung out of the housing (164). 21. Method for surface treatment of parts in treating stations (12-21, 141, 162), especially in treating baths, wherein the parts (42) are each mounted on a holding fixture (40) pivotally received on a carrying element (36) that can be displaced along a conveyor means (22), the parts (42) being transported to the treating stations (12-21, 141, 162) by moving the carrying elements (36) along the conveyor means (22), being positioned above or below the stations and are swung into and out of the treating stations (12-21, 141, 162) by a slewing movement about a substantially horizontal pivot axis (38), characterized in that the parts (42), are mounted and preferably driven laterally 29 outside a treating station (12,21, 141, 162) at any time during movement into and out of the treating stations (12-21, 141, 162). 22. The method as defined in claim 22, characterized in that the parts (4 2) are moved by the conveyor means (22) through at least one treating station (162) which is enclosed by a housing (164), being swung into the housing (164) through a lead-in opening in the bottom or the cover of the housing (164), being then transported through the housing (164) in upright or suspended condition, and being thereafter swung out of the housing (164) through leadout opening (170). The invention proposes a device and a method for surface treatment of parts by dipping processes, having treating stations (15) for treatment of the parts (42, 42') by a dipping process, conveyor means (92) for transport of the parts, which extends outside the treating stations (15) and along which can be moved a plurality of carrying elements each provided with a holding fixture (40) for fixing at least one of the parts to be treated, each of the parts (42, 42') being mounted on the holding fixture (40) for pivotal movement about a horizontal pivot axis (100) in a position outside the treating station (15) from where it can be moved into and withdrawn from the treating station (15) by a slewing movement.

Full Text

1
DEVICE AND METHOD FOR SURFACE TREATMENT OF PARTS
The present invention relates to a device for surface treatment of parts having treating stations, especially treating baths, for treating the parts comprising conveyor means for transport of the parts along which is movably guided at least one carrying element provided with a holding fixture for fixing at least one of the parts to be treated, the holding fixture being pivotally supported on a slewing device with a substantially horizontal pivot axis, the arrangement being such that movement of the carrying element causes the parts to be moved along the conveyor means into an operating position above or below a treating station, the carrying element being configured so that the parts can be swung into and out of the treating station in their working position above or below a treating station.

2
The invention further relates to a method for the surface treatment of parts in treating stations, wherein the parts are mounted on a holding fixture pivotally supported on a carrying element that can be displaced along conveyor means, whereby during movement of the carrying elements the parts are moved to the treating stations along the conveyor means, are positioned above or below the latter, and are swung into and out of the treating stations by a slewing movement about a substantially horizontal pivot axis.
The term "surface treatment of parts" as used in the present application is meant to describe any chemical and/or physical treatment of parts, including any chemical pre-treatment, such as, for example, ungreasing, washing, activating, zinc phosphating operations, etc. Alternatively, or in addition to this interpretation, the term "surface treatment of parts" is intended to include also a coating process or some surface treatment of the parts as such, including for example a dip-coating process.
A device and a method of the before-mentioned kind have been known from DE-A-200 22 634. In this case, guide means are provided in the area of the treating stations for guiding the movement of bogies each of which is provided with a rotatable support for a vehicle body, the arrangement being such that the vehicle body can be moved into and out of the treating station by rotation about an axis of rotation. Each of the bogies is provided in this case with a separate drive and can be moved independently one from the other.

3
Although such a design permits the transport of the parts between the treating stations to be realized in a relatively simple way, and facilitates movement of the parts into and out of a treating station, such a device and such a method frequently cannot guarantee the quality demands placed on the quality of the finished surface that have become more stringent lately.
Now, it is the object of the present invention to provide a device and a method for the surface treatment of parts at the highest possible quality whereby the least possible amount of defects on the finished surface, for example the coated surface, can be achieved. At the same time, the invention is intended to provide a structure with the highest possible reliability and cost-saving effect.
This object is achieved, by a device of the kind described above, in that a holding fixture is pivotally mounted on pivot bearings which, in a working position in which a part is to be swung into or out of a treating station, is positioned laterally outside the treating station.
With respect to the method, the object is achieved by a method of the before-mentioned kind in that during the slewing movement into and out of the treating station, the parts are held, and are preferably driven, laterally outside of one of the treating stations.
The object of the invention is thus perfectly achieved.

4
Given the fact that according to the invention the holding fixture intended to mount the parts in a working position, for being swung into and out of a treating station, is arranged laterally outside the treating station, contamination of, for example, treating baths by lubricant or the like leaking from the pivot bearings is prevented. The possibility of foreign particles being introduced into the treating stations is thereby reduced to a minimum.
The statement that the pivot bearings are arranged "laterally outside the treating station" is intended to mean in the context of the present invention that the pivot bearings are offset relative to the treating station far enough to ensure that contamination of the treating station by contaminants from the pivot bearings is avoided. If, for example, the treating station is a treating bath this means that the pivot bearings must not be arranged vertically above the surface defined by the treating bath, but must be offset laterally to the outside. When the treating station is protected from the outside by a housing, the pivot bearings may be provided inside the housing, but in a position laterally offset from the surface defined by the treating bath.
Further, the invention ensures by a suitable arrangement and configuration of the conveyor means and carrying elements that the parts to be treated can be swung into and out of a treating station by a slewing movement. This guarantees an especially simple and cost-saving process flow.
The conveyor means extends in this case preferably laterally beside the treating stations or, alternatively, above or below

5
the treating stations. In cases where the conveyor means is arranged laterally beside the treating stations a cantilever arm, projecting horizontally in the direction of a treating station, enables a part to be positioned in a working position above or below a treating station where a single slewing movement is required to swing the part into or out of the treating stations. When the conveyor means is arranged above the treating stations, at least in part, the carrying elements are suspended on the conveyor means and can preferably be displaced along the conveyor means by a separate drive.
According to a preferred further development of the invention the conveyor means extends outside the treating station.
Such an arrangement, in which the conveyor means is arranged laterally offset from the treating station, prevents contamination of the treating station by contaminants that may leak out from the conveyor means.
In this connection, the conveyor means may further be separated from the treating station by a wall.
According to an advantageous further development of the invention, the slewing device comprises a slewing drive located laterally outside the corresponding treating station in its working position.
This also prevents contamination of the treating station by the slewing drive.

6
According to a further advantageous embodiment of the invention, the carrying element comprises a cantilever arm, projecting from it in horizontal direction, on which is provided the holding fixture which can be positioned above of below a treating station.
This permits the conveyor means for the respective carrying elements to be provided completely laterally outside the treating stations. Transferring the parts into the working position, for being swung into a treating station, is rendered possible in this case by the cantilever arm projecting in horizontal direction. The conveyor means being thus arranged completely laterally outside the treating stations, it is easily accessible for maintenance and repair work.
In cases where the treating station is separated from the conveyor means by a wall, the cantilever arm preferably extends through a slot provided in the wall.
This minimizes any contamination of the parts during surface treatment thereof.
According to a further development of the invention, there is provided a control device, which is coupled at least with the conveyor means and the slewing devices for controlling the movement of parts to be treated.
This permits optimum treatment of the parts in the treating stations to be achieved.

7
The slewing device permits movements into and out of the working position to be realized at any desired angle. This considerably reduces any inclusion of air during the dipping process so that coating defects are avoided. The slewing movement can be effected also during the treating and/or coating time within the treating station, whereby a more intensive flow around the part being treated can be achieved. Due to the relative movement of the part, this also allows any air bubbles, that may still be present, to migrate so that all surfaces can be pretreated and/or coated in the best possible way.
Depending on the particular design of the slewing device and the cantilever arm on which it is received, a slewing movement of up to 180° or even a slewing movement over full 360° or more can be realized. This permits the parts to be moved into a treating station, and to be later removed from it, by a single slewing movement without the need for additional lifting means. It is, thus, possible to swing the parts from a horizontal position into an overhead position in a treating station. This permits surfaces, that need to be pre-treated and coated at high quality, to be positioned in the treating station with the face down, whereby any contamination by deposition of particles on such surfaces in the treating baths is excluded. Further, a slewing movement permits optimum draining off of the parts to be dipped so that entrainment of bath liquid, for example between different treating baths, is minimized. Even more complex, scoop-type parts can be coated in this way free from defects. In addition, the sequence of the dipping and/or lifting operations can be adapted in this way to the geometry, stability and the dripping behavior of a vehicle body, for

8
example. For example, a part can be stopped for a given time in vertical position in order to improve the dripping process.
According to a further advantageous embodiment of the invention, each carrying element comprises a drive for displacement along a guide of the conveyor means.
One thereby achieves the greatest possible flexibility for the movement of the different carrying elements and, thus, the parts to be treated. Even a limited return motion is rendered possible. This is advantageous in particular for smaller systems . For example, it is possible to use a single washing bath after two different processes, such as an ungreasing and a phosphating process, by moving the part from the phosphating bath back to the washing bath. This allows an especially compact structure for smaller throughputs.
In this case, the slewing device preferably comprises a slewing drive, which is supplied with energy via the conveyor means.
Preferably, this is effected by supplying the slewing drive with energy via a carriage mounted for displacement along a guide of the conveyor means.
One avoids in this way the use of trailing cables, which otherwise would be required for the energy supply of the slewing drives.
According to a further advantageous development of the invention, the conveyor means is configured as a telpher line system.

9
As is generally known, telpher line systems comprise a carrying and guide element for example in the form of an I section. The carrying and guide element is further provided with integrated current busbars by means of which vehicles guided on a carriage can be supplied with energy. Further, such busbars serve to exchange control signals so that the vehicles can be driven independently and can be displaced in a controlled way. Preferably, the different vehicles are equipped in this case with a separate small SPS control system.
Such a conveyor arrangement permits especially flexible production processes to be guaranteed for the surface treatment of parts. A highly flexible process flow can be guaranteed especially in combination with a central host computer coupled with the separate control systems of the vehicles.
In an advantageous further development of the invention, the holding fixture comprises a preferably U-shaped, H-shaped or rectangular slewing frame mounted on pivot pins, on which mounting elements for mounting the part to be treated are received.
This ensures an especially simple structure of the holding fixture, suited for a swinging motion for swinging parts into and out of the respective working position. An especially favorable dripping behavior is achieved, in particular, with a Ushaped frame. Preferably, the slewing frame as such is located outside of the dripping area of the part to be treated, for which purpose inwardly projecting brackets or tongues, on which

10
struts holding the parts are arranged, may be provided on the slewing frame. This minimizes any contamination.
According to another embodiment of the invention, a plurality of carrying elements is driven by means of a circulating conveyor.
This provides an especially cost-saving way of driving the conveyor means. The carrying elements are driven in this case either jointly by one trailing drive, or preferably independently.
According to an additional further development of the invention, a lifting device is provided on the at least one carrying element, by means of which the cantilever arm is received on the carrying element for displacement in vertical direction.
This permits a lifting movement to be carried out in addition to the slewing movement, whereby optimum treatment is rendered possible. The slewing movement and the lifting movement can be adapted in this case to the particular structure of the parts to be treated so as to achieve an especially favorable dipping behavior, minimization of the formation of air bubbles during treatment, an especially uniform treatment and best possible draining off when the part is removed from a treating bath.
In an additional further development of the invention, the conveyor means is configured as a circulating conveyor one working section of which extends along the side faces of the treating stations in a first direction (X direction), while the return section is guided back at a distance from the treating

11
stations, with head sections formed between the working section and the return section that comprise a transfer position, for allowing the parts to be treated to be taken over at one of the head sections, and a takeover position allowing the parts to be treated to be discharged at the other head section. There is also the possibility to use the different head sections for both the takeover and the discharge of parts.
One thus achieves an especially compact and cost-effective overall arrangement. For, a circulating conveyor is in a position to run around all treating stations. The cornering movements in the transition area between the working section and/or the return section and the head sections permit the parts conveyed, which as a rule contact the respective sections in lengthwise direction, to be directly taken over in that position at the transfer position by the holding fixture of a slewing device, and, during the next following cornering movement, to be brought to the correct position in which it can be dipped into a treating bath, for example, by a corresponding slewing and/or lifting movement. Correspondingly, it is also possible to discharge the treated parts at the opposite head section of the circulating conveyor in the transfer position, either in a first direction (X direction) or in a direction perpendicular thereto, in order to convey the parts to a subsequent process, for example to a baking system. This avoids the need for additional conveyor means, such as turntables or the like. Basically, there is of course also the possibility to arrange the transfer operation along the longitudinal sections.
According to an additional further development of the invention, at least one of the treating stations is configured as a

12
spray tunnel or a washing tunnel. In this case, the treating station is preferably provided with cover plates that can be moved together above the treating station.
This then even permits a spray treatment to be carried out.
Preferably, the cover plates are provided with longitudinal slots for the forward and return movement of the carrying elements, and with transverse slots that permit the carrying element to be slightly pivoted about a pivot axis extending in the conveying direction.
It is possible in this way to perform a movement during the spray pre-treatment in order to achieve a uniform spray pattern.
According to a further development of the invention, at least one of the treating stations is configured as a drying station, baking stove, inspection room, cooling station, bonding station or underbody coating station.
This permits the use of the conveyor means to guarantee full transport of the parts not only through the pre-treating stations, but also through other stations, such as a dip-coating system. This avoids the need for transfer operations, which improves the quality of the surfaces produced.
In the case of stations enclosed by a housing, a lead-in opening enabling a carrying element to be swung into the housing is provided for this purpose, preferably in the bottom or in the cover, which opening is connected, via a slot extending in the

13
direction of the conveyor means, with a Lead-out opening enabling the carrying element to be swung out of the housing.
This permits a part, which is received on a carrying element, to be swung into the housing at the beginning of the housing, to be transported therein in vertical position, and to be swung out of the housing at the end of the treatment. As this permits the parts to be transported, for example, in upright position during treatment, for example in a dryer, one thereby obtains surfaces of especially high quality.
It is understood that the features of the invention mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention.
Certain preferred embodiments of the invention will be described hereafter with reference to the drawings in which:
Fig. 1 shows a diagrammatic, largely simplified overall top view of a device according to the invention;
Fig. 2 shows a largely simplified cross-section through the
device according to the invention, taken in a plane
perpendicular to the first direction (main transport
direction);
Fig. 3 shows a modification of the embodiment illustrated in Fig. 2;

14
Fig. 4 shows another modification of the invention, represented in a simplified front view, of a holding fixture for a part to be treated;
Fig. 5 shows a side view of the carrying element and the holding fixture of an embodiment slightly modified by comparison with Fig. 1;
Fig. 6 shows another modification of the invention, represented by a simplified top view, of a carrying element with cantilever arm;
Fig. 7 shows an enlarged section of a device according to the invention, as shown in Fig. 4;
Fig. 8 shows another modification of the embodiment of Fig. 4, where the treating station is configured as a spray
tunnel;
Fig. 9 shows a top view of the cover plates of the spray tunnel according to Fig. 8;
Fig. 10 shows another modification of the invention, where the holding fixture with the parts received on it can be transported through a slot in the bottom of the treating station in upright position; and
Fig. 11 shows a simplified bottom view of the device according to Fig. 10.

15
Fig. 1 shows a largely simplified top view of a device according to the invention for the surface treatment of parts, indicated generally by reference numeral 10.
The device 10 comprises a plurality of treating stations in the form of treating baths 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 of rectangular outline, having their long sides arranged one adjacent the other, so that their short sides extend in a first direction (X direction). The treating baths 12-21 may for example include baths for dip-ungreasing, dip-washing, activation, zinc phosphating, dip-washing in fully desalinated water, dipcoating, and the like.
A plurality of carrying elements 36, of which only four elements 36, 36', 36', 36'', intended to transport the parts through the device 10 and to dip and remove the parts into and from the treating baths 12-21, are shown by way of example, are illustrated in different positions. Each of the carrying elements 36 comprises a cantilever arm 41 that projects in a substantially horizontal direction. The outer end of each cantilever arm 41 carries a slewing arrangement, indicated generally by 37, by means of which a holding fixture 40 for parts 42 to be treated can be swung about a pivot axis 38, as indicated diagrammatically by double arrow 39 near the slewing device 37. Parts 42 to be treated, which may for example consist of vehicle bodies (body shells), are each mounted on the holding fixture 40 of a slewing device 37, are moved to the respective treating baths 12-21 by corresponding movements of the carrying elements 36, are dipped into and removed from the baths by operation of the slewing device 37, and are finally caused to leave the last treating bath 21 before they can be transferred

16
to a subsequent system at a position indicated by reference numeral 42'.
The transport of the carrying element 36 is effected by conveyor means 22, indicated generally by reference numeral 22, which takes the form of a circulating conveyor that may be driven by a trailing drive or may comprise individually driven, separately displaceable carrying elements 36. The conveyor means 22 comprises a working section 24, extending along the short sides of the treating baths 12-21 in a first direction (X direction), a return section 26, extending in parallel to and at a distance from the working section 24, for the return movement of the carrying elements, a first head section 2 8 and a second head section 30. In the area of the first head section 28, the carrying element 36 with its holding fixture 40 occupies a transfer position 32 in which the parts 42 to be treated can be conveyed from a preceding production station in the direction indicated by arrow 43 in a first direction (X direction) and can be fixed on the holding fixture 40.
As a result of the movement along the conveyor means 22 out of the transfer position 32 in the direction indicated by arrow 44, a part 42 having been taken over in the transfer position 32 is now pivoted by 90°, whereafter it arrives at the treating baths 12-21 along which it is transported in the X direction, as indicated by arrow 45. Once it has left the last treating bath 21, the carrying elements are once more pivoted by 90°, as indicated by arrow 46, at the transition from the working section 24 to the second head section 30. This leads to a transfer position 34 at the second head section 30 in which parts 42 ' , that have been treated, can be either withdrawn in the X direc-

17
tion or displaced laterally in the Y direction, perpendicular to the X direction, as indicated by arrow 47, for being transferred to a subsequent production station, for example a baking installation.
The structure of the carrying elements, together with the slewing arrangements, will now be described in more detail with reference to Figs. 2 to 4.
In Fig. 2, a treating bath 15 can be seen with a carrying element 36 arranged in front of its end face. The carrying element
36 is received on a guide 52 of the conveyor means 42, shown
diagrammatically only, which is separated from the space in
which a treating bath 15 is enclosed by a wall 53. The carrying
element 36 comprises a cantilever arm 41, projecting in a di
rection toward the treating bath 15, so that a slewing device
37 carried at the end of a cantilever arm 41 has its pivot axis
38 located centrally above the treating bath 15. The cantilever arm passes through a slot 55 extending in the wall 53 in the direction of extension of the conveyor means 22. Mounted on the slewing device 37 is a holding fixture 40 in which a part 42 to be treated is fixed. In the position illustrated in Fig. 2, the part 42 to be treated can now be pivoted in downward direction by a slewing movement about the pivot axis 3 8 in the direction of double arrow 51, until the part 42 to be treated is completely submerged in the treating bath 15. The slewing process may also be continued during the treating time in order to achieve uniform treatment and to remove as far as possible any air bubbles that may adhere to the surfaces. At the end of the treatment, the part 42 is removed from the treating bath 15 by the reverse motion sequence and can then be transported on by

18
operation of the conveyor means 22 or of an independent drive of the carrying element 36.
Other carrying elements 36' with a cantilever arm 41', a slewing device 37, which can be swung about the pivot axis 38', and a holding fixture 40' is shown in the right half of Fig. 2, in the area of the return section 26 of the conveyor means and, thus, during its return movement in the direction toward the transfer position 32 of the conveyor means.
A slightly modified embodiment is shown in Fig. 3 and indicated generally by reference numeral 60.
In this and the following figures, corresponding parts are indicated by corresponding reference numerals.
The essential difference to the embodiment discussed with reference to Fig. 2 consists in that in this case, instead of being mounted directly on the respective carrying element 36, the cantilever arm 41 is mounted on a lifting arrangement 48 mounted on the carrying element 36 to move vertically (in the 2 direction) in the direction indicated by double arrow 4 9. The carrying element 36 is again firmly mounted on a guide 54 of the conveyor means 22, but is located in the space in which the treating bath 15 is put up, though at a lateral distance therefrom. The slewing device 37 mounted at the outer end of the cantilever arm 41 by means of which the holding fixture 40 for a part 42 can be swung in the direction indicated by arrow 50 can be additionally lifted or lowered in the direction of arrow 49.

19
It is understood that the slewing movement about the pivot axis 38 and the lifting movement in the direction of arrow 49 can be jointly controlled in this case by a central control 56, for example a SPS control, in order to thereby realize optimum conditions for the dripping and removal motions and, if desired, predetermined motion curves during the time of treatment.
This permits surface treatments of especially high quality to be achieved depending on the nature of the respective parts to be treated.
An embodiment of the device according to the invention, that has been slightly modified by comparison with the embodiment illustrated in Fig. 2, is illustrated in Fig. 4 and indicated generally by reference numeral 70. The holding fixture 40 intended to receive a part 40 to be treated is mounted on the carrying arm 41 of the carrying element 36. The holding fixture 40 comprises a substantially U-shaped slewing frame 97 on which four struts 98 are provided in the illustrated arrangement, the outer ends of which carry a part 42 to be treated, for example a body shell, which is fixed on it by mounting elements 99 (such as clamps). Laterally, the slewing frame 97 is pivotally seated on pivot pins 100 in pivot bearings 101. The pivot bearings 101 are mounted on the cantilever arm 41. The pivot bearings 101 are located a sufficient distance laterally outside the treating bath 15 provided underneath so that the vertical downward projection from the pivot bearings 101 comes to lie outside the treating bath 15. Any contaminants that may leak out from the pivot bearings 101 are thereby prevented from getting into the treating bath 15. Further, the chain wheels

20
(or alternatively rollers) of two pivot drives 102, 103 (not shown), by means of which the pivot pins 100 can be pivoted via a chain or a toothed belt 106, are indicated at the outer ends of the pivot pins 100 in Fig. 4. The arrangement of the slewing frame 97 preferably is such that the slewing frame 97 as such is already located outside the dripping area of the part 4 2. Only four brackets or tongues 118, that carry the struts 98 and that project inwardly from the slewing frame 97, are located in the dripping area. This minimizes both contamination and entrainment of the baths.
Generally, seating the elements and their drive laterally outside the treating bath 15 located underneath guarantees that no contaminants from a seating or driving system for the slewing arrangement can get into the treating bath 15.
The position of a part that has been pivoted in downward direction and into the treating bath 15 is indicated by the broken line 42 '.
Fig. 5 shows an embodiment slightly modified by comparison with the embodiment according to Fig. 4, which is indicated generally by reference numeral 90. In this case, the cantilever arm 41 is arranged in the same plane as the pivot bearings and the pivot drive 103. This permits the conveyor means with the carrying element 36 to be separated by a wall 53 from the space in which the treating bath 15 is set up. The pivot drive 103 is driven by a chain or a belt 106 that extends through a slot 55 in the wall 53, in the same plane as the cantilever arm 41. All drive elements are, thus, separated by the wall 53 from the space in which the treating bath is set up, being connected

21
with it merely via a thin slot 55. The carrying elements 36 may be driven, by rollers and associated drive motors (not shown), for independent displacement on a guide 52 provided below them.
Another modification of the device according to the invention is illustrated in Fig. 6 and indicated generally by reference numeral 110.
Here again, the bearing and drive systems of the slewing frame 97 are configured in such a way that a treating bath 15 located underneath cannot be contaminated by contaminants issuing from them.
Again, a cantilever arm 41 is mounted on the carrying element 36 and projects through the slot in the wall 53 in horizontal direction relative to the treating bath 15. A slewing frame 97 of substantially U-shaped configuration is pivotally mounted on the outwardly projecting free ends of the likewise substantially U-shaped cantilever arm 41. On the slewing frame 97, there can be seen four struts 98 serving to connect the frame with a part 42 indicated in broken lines. As has been discussed before in connection with Fig. 4, the slewing frame 97 is received on pivot pins 100 in pivot bearings 101 seated on the free ends of the cantilever arm 41. Two drive motors 111, indicated on the carrying element 36, are coupled via a shaft 109 for driving toothed belt drives 102, 103 via drive pulleys 110, 111.
Further, two drive motors 112, 113 ensuring the movement along the guide 32, and a support roller 114 intended to support the

22
carrying element 36 at its upper end on the wall 53 can be seen on the carrying element 36.
Fig. 7 shows an enlarged detail of Fig. 4. As can be clearly seen in Fig. 7, the brackets 118 project inwardly a sufficient length to provide a vertical distance d between the outer edge of the mounted part 42 and the slewing frame 97. The slewing frame 97 as such is, therefore, already located clearly outside the dripping area, as indicated by the distance d between the lateral edge of the part 42 and the slewing frame 97. Optionally, additional small nozzles may be provided on the slewing frame 97 to provide the possibility to shortly rinse the parts, which may have been contaminated by the bath liquid, above the bath before they are transported to the next bath.
Another modification of the device according to the invention is illustrated in Figs. 8 and 9 and is indicated generally by reference numeral 140.
In this case, the treating station takes the form of a spray tunnel 141. The spray tunnel 141 is closed off on its upside by two cover plates 146, 147, which can be laterally closed, for moving the parts in and out, as indicated by arrows 148, 149. Once a part has been moved into the spray tunnel 141, the cover plates 146, 147 are closed and the spray treatment can begin. As can be seen in Fig. 9, slots 150, 151 may be provided in the cover plates 14 6, 147, which altogether provide two H-shaped openings and which during the spraying treatment permit both a forward and backward movement and a slight slewing movement so that a uniform spay pattern can be achieved. There can be further seen in Fig. 8 the reservoir 143 in which the treating

23
liquid is collected and from which the treating liquid is supplied to the numerous spray nozzles 142 by a pump 144.
A further embodiment of the invention is illustrated in Figs. 10 and 11 and is generally indicated by reference numeral 160.
This embodiment is modified relative to Figs. 8 or 9 in that it shows a treating station 162, for example in the form of a dryer for a KTL baking process, through which the parts 42 can be moved in upright condition. This means that during treatment the parts 4 2 are held on the slewing frame 97 from below. Conveying the part 42 in upright position through the housing 164 is rendered possible by a longitudinal slot 166 in the bottom 165 of the housing 164 enclosing the dryer 162. It can be seen in Fig. 11 that a lead-in opening is provided in the bottom 165 on the inlet side of the housing 164, which permits a carrying element 36 with a part 4 2 mounted thereon to be pivoted into an upright position from below. This position is then followed, for example, by three treating positions inside the housing 164, as indicated by broken lines. At the outlet end of the dryer 162, there is correspondingly provided a lead-out opening 170 through which the carrying element 36 with a part 42 mounted thereon can be removed by a downward pivoting movement.

24
A device for surface treatment of parts having treating stations (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 141, 162), in particular, treating baths, for treatment of the parts (42, 92) , comprising a conveyor means (22, 92) for transport of the parts along which is movably guided at least one carrying element (36) provided with a holding fixture (40) for fixing at least one of the parts (42) to be treated, the holding fixture being pivotally supported on a slewing device (37) with a substantially horizontal pivot axis (38), the arrangement being such that movement of the carrying element (36) causes the parts (42, 92) to be moved along the conveyor means (22, 92) into a working position above or below a treating station (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 141, 162), the carrying element (36) and the holding fixture (40) being configured so that the parts (42, 92} can be swung into and out of the treating station (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 141, 162) ' in their working position above or below a treating station, characterized in that the holding fixture (40) is pivotally mounted on pivot bearings (101) which, in a working position in which a part is to be swung into or out of a treating station, is positioned laterally outside the treating station (12-21, 141, 162).
The device as defined in claim 1, characterized in that the conveyor means (22) along which the at least one carrying element (36) can be moved, extends outside the treating stations (12-21, 141, 162 ).

25
3. The device as defined in claim 2, characterized in that
the conveyor means (22) is separated from the treating
station (15) by a wall (53).
4. The device as defined in claim 1, claim 2 or claim 3, characterized in that the carrying element (36) comprises a cantilever arm (41), projecting from it in horizontal direction, on which is provided the holding fixture (40) which can be positioned above of below a treating station (12-21, 141, 162).
5. The device as defined in claim 4, characterized in that the cantilever arm (41) extends through a slot (55) in a wall (53) which separates the conveyor means (22) from the treating stations (12-21, 141, 162).
6. The device as defined in any of the preceding claims, characterized in that the slewing device (37) comprises a slewing drive (102) which in the working position is located laterally outside the corresponding treating station (12-21, 141, 162), being preferably separated therefrom by a wall (53).
7. The device as defined in any of the preceding claims, characterized in that each carrying element (36) comprises at least one drive (112, 113) for displacement along a guide (52) of the conveyor means (22).
8. The device as defined in any of the preceding claims, characterized in that the holding fixture (40) comprises a preferably U-shaped, H-shaped or rectangular slewing frame

26
(97) mounted on pivot pins (100), on which mounting elements (99) for mounting a part (42) to be treated are received.
9. The device as defined in claim 8, characterized in that
the slewing frame (97) can be pivoted by more than 180°,
preferably by 360°.
10. The device as defined in any of the preceding claims, characterized by a lifting device (48) by which the holding fixture (40) is mounted on the carrying element (36) for displacement in vertical direction.
11. The device as defined in any of the preceding claims, characterized by a control device (56) which is coupled at least with the conveyor means (22) and the slewing device (37) for controlling the movement of parts (42) to be treated.
12. The device as defined in any of the preceding claims, characterized in that a plurality of carrying elements (36) is driven along a circulating conveyor (22).
13. The device as defined in claim 12, characterized in that the conveyor means (22) is configured as a circulating conveyor one working section (24) of which extends along side faces of the treating stations (12-21) in a first direction (X direction), while a return section (26) is guided back at a distance from the treating stations (1221, 71), with head sections (28, 30) formed between the working section (24) and the return section (26) that com-

27
prise a transfer position (32) , for allowing parts (42) to be treated to be taken over at one (30) of the head sections (30, 32), and a takeover position (34) allowing parts (42) to be treated to be discharged at the other head section (32) .
14. The device as defined in any of the preceding claims, characterized in that the slewing device (37) comprises a slewing drive (102, 103) which is supplied with energy via the conveyor means (22).
15. The device as defined in claims 1 to 11, 13 or 14, characterized in that the conveyor means is configured as telpher line system.
16. The device as defined in any of the preceding claims, characterized in that at least one of the treating stations (141) is configured as a spray tunnel or a washing tunnel.
17. The device'1 as defined in claim 16, characterized in that the treating station (141) is provided with cover plates (146, 147) that can be moved together above the treating station (141).
18. The device as defined in claim 17, characterized in that the cover plates (146, 147) are provided with longitudinal slots (150) for the forward and return movement of the carrying elements (36) , and preferably with transverse slots (151) that permit the carrying elements (36) to be

28
slightly pivoted about a pivot axis extending in the conveying direction (22).
19. The device as defined in any of the preceding claims, characterized in that at least one of the treating stations (162) is configured as a drying station, baking stove, inspection room, cooling station, bonding station or underbody coating station.
20. The device as defined in claim 19, characterized in that the at least one treating station (162) is enclosed by a housing (164) the bottom or cover of which comprises a lead-in opening (168) for permitting the carrying element (36) to swung into the housing (164), which opening is connected, via a slot (166) extending in the direction of the conveyor means (22), with a lead-out opening (170) enabling the carrying element (36) to be swung out of the housing (164).
21. Method for surface treatment of parts in treating stations (12-21, 141, 162), especially in treating baths, wherein the parts (42) are each mounted on a holding fixture (40) pivotally received on a carrying element (36) that can be displaced along a conveyor means (22), the parts (42) being transported to the treating stations (12-21, 141, 162) by moving the carrying elements (36) along the conveyor means (22), being positioned above or below the stations and are swung into and out of the treating stations (12-21, 141, 162) by a slewing movement about a substantially horizontal pivot axis (38), characterized in that the parts (42), are mounted and preferably driven laterally

29
outside a treating station (12,21, 141, 162) at any time during movement into and out of the treating stations (12-21, 141, 162).
22. The method as defined in claim 22, characterized in that the parts (4 2) are moved by the conveyor means (22) through at least one treating station (162) which is enclosed by a housing (164), being swung into the housing (164) through a lead-in opening in the bottom or the cover of the housing (164), being then transported through the housing (164) in upright or suspended condition, and being thereafter swung out of the housing (164) through leadout opening (170).
The invention proposes a device and a method for surface treatment of parts by dipping processes, having treating stations (15) for treatment of the parts (42, 42') by a dipping process, conveyor means (92) for transport of the parts, which extends outside the treating stations (15) and along which can be moved a plurality of carrying elements each provided with a holding fixture (40) for fixing at least one of the parts to be treated, each of the parts (42, 42') being mounted on the holding fixture (40) for pivotal movement about a horizontal pivot axis (100) in a position outside the treating station (15) from where it can be moved into and withdrawn from the treating station (15) by a slewing movement.

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Patent Number

212700

Indian Patent Application Number

01014/KOLNP/2004

PG Journal Number

50/2007

Publication Date

14-Dec-2007

Grant Date

12-Dec-2007

Date of Filing

19-Jul-2004

Name of Patentee

EPV-TEC GMBH

Applicant Address

SANDWEG 20, 75179 PFORZHEIM

Inventors:

#	Inventor's Name	Inventor's Address
1	SAUPE DETLEV	KEPLERSTR. 27, 75203 KONIGSBACH-STEIN
2	WURSTER GERD	BIRKENDORTLE 15, 70191 STUTTGART

PCT International Classification Number

B65G49/04

PCT International Application Number

PCT/EP03/00473

PCT International Filing date

2003-01-18

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	102 02 625.4	2002-01-21	Germany
2	102 39 484.9	2002-08-21	Germany