Abstract: In an assembly line of a vehicle body W, vehicle body parts differentiated in accordance with the vehicle body type are clamped on respective carriages travelling on an assembly line 1 for sequentially executing temporary welding and power-increased welding for assembling the vehicle body W. An exclusive carriage 3A (3B), clamping parts of the vehicle body W in position for temporary welding, causes a reciprocative movement between a part-supplying station S1 and a temporary welding station S2. A common carriage 10A carrying the vehicle body W causes a reciprocative movement between the temporary welding station S2 and a power-increased welding station S3. Welding robots 29, 29 of the temporary welding station S2 perform the temporary welding for connecting the parts clamped in position on the exclusive carriage 3A (3B). Thus temporarily welded body assembly is lifted and transferred onto a side rotary jig 24 and supported in position for power-increased welding.

Abstract: A breather pipe mounted to a fuel tank is divided into an outer pipe and an inner pipe, a flange is integrally formed at an end part of the outer pipe on the tank side, then the flange is projection-welded to a wall part of the fuel tank, ensuring a sealability. An upper end of the inner pipe is inserted and held to a lower end of the outer pipe in the fuel tank, and the outer pipe and the inner pipe are sealed by a sealing member, tapering joint or caulking joint. Thus, the sealability at the joint part is ensured, while enhancing a joint strength without soldering which involves pollution.

Abstract: Molds are exchanged by moving a carrier loaded with a cradle between below a mold fitting position of a blow molding apparatus and the mold carrying in and out position. The cradle for supporting the mold is provided with an air blowing means for letting an air into a parison at the time of molding.

Abstract: In a first station, a first part is set to a work at a predetermined position thereof, and the work is then conveyed to a second station by a first jig truck, and the first jig truck which has finished such a conveyance, is then returned back to the first station from the second station. In the second station, the first part is spot-welded to the work, and the work thus spot-welded is conveyed to a third station by a second jig truck. In the third station, a second part is set to a predetermined position of the work with which the first part has been assembled, and the work is then conveyed to a fourth station by the second jig truck. In the fourth station, the second part is spot-welded to the work, and the second jig truck which has conveyed the work to the fourth station, is returned back to the second station from the fourth station through the third station.

Abstract: A detaching and attaching device is provided at one end side of a carrier which moves between below the parts fitting position and the parts carrying in and out position and a transferring device is provided at the other end side. Articles are attached to and detached from an object of attachments by moving the carrier toward below the parts fitting position and by the detaching and attaching device. At this time, by working the transferring device, while detached articles are received from the detaching and attaching device, articles to be fitted are delivered to the detaching and attaching device.

Abstract: A first plate member is insetted at its end portion between a body part and a return part of a second plate member. A first swelling part is formed at the end portion of the first plate member so as to protrude to a side of the return part of the second plate member. A second swelling part is formed at a portion corresponding to the first swelling part in the return part of the second plate member so as to be in face-to-face contact with the first swelling part. The first and second swelling parts are joined by laser welding.