PURPOSE: To obviate the formation of any clearance in coupling even without welding, by forming a sheet material to a cylindrical shape, and engaging the engaging part and the part to be engaged formed on each joining end of the sheet material.
CONSTITUTION: The side edges of a sheet material 1 cut from a sheet steel into a rectangular shape are formed to joining ends 2a, 2b. A press-contact surface 6 which is cut off in a step shape on the top face side is formed to one joining end 2a, and an engaging projected line 7 projected upward along the joining end is provided to the end of the press-contact surface 6. This projected line 7 is used as an engaging part 3. The other joining end 2b is formed onto the surface 8 to be press-contacted of which the under surface side is cut off in a step shape. Next, this sheet material 1 is curved to a cylindrical shape, and the surface 6 and the surface 8 are caused to press-contact, thereby penetrating the projected line 7 into the surface 8 and forming the surface 6 and the surface 8 into one piece. In this case, the part of the surface 8 dented by the projected line 7 serves as an egaging groove 9 and this groove 9 is the part 4 to be engaged. In this way, the coupling B is formed.
OBATA SOTOJI
OGASAWARA MASANOBU
OZASA TAKASHI
| JPS54149369A | 1979-11-22 | |||
| JPS54149370A | 1979-11-22 | |||
| JPS5154864A | 1976-05-14 | |||
| JPS5154863A | 1976-05-14 | |||
| JPS4925549A | 1974-03-07 | |||
| JP51079548B |