Abstract: A robot arm including a first joint, a second joint, and a coupling element is provided. The first joint has a first inclined surface. The second joint is jointed to the first joint and has a second inclined surface. The coupling element has a third inclined surface and a fourth inclined surface opposite to the third inclined surface, wherein the third inclined surface contacts the first inclined surface, and the fourth inclined surface contacts the second inclined surface.

Abstract: A multilevel container having a circumferentially continuous wall or bottom elements of sheet metal with radially outwardly beaded end faces. The wall and bottom elements are placed on top of each other on butt joints so as to seal the end faces and are detachably braced with a minimum of one neighboring container level. The multilevel container also comprises one or more sealing rings and bracing components that act on neighboring end faces. In order to provide a readily manufacturable and form a stable multilevel container without multiple beads in alternating directions or weldings in the butt joint portions, a separate and independent shape retaining ring is provided. This ring reinforces the container and has shape retaining surfaces on its two end faces. In the region of their end faces, the neighboring wall and bottom elements are set on and tightly braced against the shape retaining surfaces of the reinforcing shape retaining ring.

Abstract: The present invention provides a fuel tank or a fuel pipe excellent particularly in the corrosion resistance of the outer surface in a salt damage environment, and is a fuel tank or a fuel pipe excellent in corrosion resistance characterized by: being formed by using a steel sheet or a steel pipe containing Cr of 9.0 to 25.0 mass % as the base material; on the outer surface thereof, having any one or more of welded portions, brazed portions and structurally gapped portions contacting components; and having one or more of metals, whose electrode potential in a 5%-NaCl aqueous solution at 30° C. is ?0.4 V or less relative to a saturated calomel electrode, attached to at least a part or parts of said portion(s) of the outer surface in an electrically conductive manner.