A system for dipping workpieces into a coating tank that includes a conveyor disposed above the tank and a workpiece carrier movable on the conveyor along a path above the tank The carrier includes a box frame having pivotal corner connections and vertically spaced guide rollers disposed on lateraly opposed sides of the frame. Longing spaced cables suspend the carrier frame from winces on the conveyor for selectively raising and lowering the carrier with respect to the conveyor. The winches and cables are also selectively operable for rocking the carrier frame about a horizontal axis lateral to the path of travel along the conveyor. A pair of track rails are disposed in fixed position on laterally opposed sides of the conveyor for engaging the guide rollers on laterally opposed sides of the carrier frame during lowering of the frame into the tank and maintaining horizontal position of the carrier frame during rocking thereof within the tank. The method of this invention then includes lowering the vehicle body into an electrostatic dip tank, preferably at an angle, then rocking the forward and rearward ends of the vehicle upwardly and downwardly about a lateral axis generally perpendicular to the longitudinal axis of the vehicle, then raising the vehicle body out of the dip tank preferably at an angle relative to horizontal.

A system for dipping workpieces into a coating tank that includes a conveyor disposed above the tank and a workpiece carrier movable on the conveyor along a path above the tank. The carrier includes a box frame having pivotal corner connections and vertically spaced guide rollers disposed on laterally opposed sides of the frame. Longitudinally spaced cables suspend the carrier frame from winches on the conveyor for selectively raising and lowering the carrier with respect to the conveyor. The winches and cables are also selectively operable for rocking the carrier frame about a horizontal axis lateral to the path of travel along the conveyor. A pair of track rails are disposed in fixed position on laterally opposed sides of the conveyor for engaging the guide rollers on laterally opposed sides of the carrier frame during lowering of the frame into the tank and maintaining horizontal position of the carrier frame during rocking thereof within the tank.

A vertical dip pretreatment and electro-deposition system has a plurality of dip stations and a plurality of spray stations. The process limited dip stations, such as the degrease dip station, the phosphate dip station and the electro-coat dip station, have expandable dip tanks which can have a bulkheads that divide the tanks into two sections providing the tanks with two compartments, or have removable end walls that can be removed and replaced with a tank section. If the bulkhead divided tanks are used, during the initial period of operation when production rates would typically be less than ten to twelve jobs an hour, one compartment of each expandable dip tank is used for immersion and the other compartment left dry or used for other purposes such as storage. When volume increases to above the design capacity, the expandable tanks are expanded. If bulkhead divided tanks are used, the bulkhead is removed which joins the first and second compartments, thus doubling the length of the tank. If the removable end wall tanks are used, the removable end walls are removed and replaced with tank sections to double the length of the tanks. In operation, the system is then set up so that after the product is lowered in the expanded tank, it stays in the first half of the expanded tank for half or less of the process time. The product is then kept in the lowered position in the expanded tank and moved to the second section of the expanded tank where it remains until the end of the required process time. The index time for the system is thus half or less of the total cycle time of the process. In this manner, production throughput of the system is increased.

The invention relates to a conveyor device which is used to transport work-pieces, especially the work-pieces of motor vehicle bodies, through a processing area for surface treatment of said work-pieces, comprising a conveyor which brings the work-pieces which are respectively maintained by a holder into the processing area; transports them through said area and removes them therefrom. The inventive conveyor device requires less maintenance in comparison with known conveyor devices. The holders respectively comprise a base part which moves in a translatory movement along a conveyor device and a rotating part on which the work-piece is arranged and which is held in such a way that it is rotatable on the base part. The conveyor comprises at least one drive device enabling at least one directly driven respective holder to be driven directly in a movement along the conveyor device. The movement of the directly driven holder is transferred to an indirectly driven holder as a result of the contact between the directly driven holder and said at least one indirectly driven holder.