Method and apparatus for surface treatment on automotive bodies

A car body surface treatment method comprising:

• carrying car bodies along an assembly line;
• stopping and immersing said car bodies in surface treatment baths, the car body being placed into and taken out of the bath while being held in a side posture with a width extending in a vertical direction;
• and
• intermittently turning the car body in the bath of surface treatment solution about a longitudinal horizontal axis of the car so that the car bodies are held stationary, for a certain period of time, in a side posture with a width extending in a vertical direction, wherein the surface treatment bath is an electrodeposition coating bath.

A batch type car body surface treatment method wherein a car body being carried is stopped and immersed in a surface treatment bath for electrodeposition coating, said method further comprising the steps of:

• turning the car body about a longitudinal axis of the car so that the car body may be in a side posture with a width extending in a vertical direction;
• putting the car body into the bath while being held in the side posture;
• energizing electrodes provided in the surface treatment bath and at the same time rolling the car body about said longitudinal axis so as to carry out electrodeposition;
• and
• while keeping the electrodes energized, changing the car body to a horizontal posture and then slowly lifting the car body without interruption until the car body is taken out of the bath.

A batch type car body surface treatment apparatus comprising:

• a surface treatment line;
• a plurality of treatment stations spaced from one another along said surface treatment line;
• a plurality of surface treatment baths, one surface treatment bath being provided at each treatment station;
• a hanger conveyor for conveying, in order, car bodies along said surface treatment line from one treatment station to another, said hanger conveyor including hangers, each hanger having a pair of hanger arms supporting the car body, said hanger conveyor being located above said surface treatment baths;
• a jig means, provided at each treatment station, said jig means for receiving the car bodies from one of said hangers of said hanger conveyor, for immersing the car bodies into the surface treatment bath, said jig means moving vertically and rotating about a longitudinal horizontal axis of the car bodies, wherein, at least when the car body is being placed into the surface treatment bath, said jig means moves vertically with said car body being in a side posture;
• a pair of lifting frames, that are vertically movable, being provided on both lengthwise sides of each surface treatment bath, and wherein the jig means is pivotally supported between the lifting frames in such a way that said jig means can be rotated about the longitudinal horizontal axis of the car body;
• and
• an opening/closing means for opening and closing said pair of hanger arms to transfer the car body between the hanger and jig means.