| 摘要 |
PURPOSE:To set a back bottom and a waist bottom to a cooperation state and an independent operation state by changing the connection positions of both bottoms. CONSTITUTION:In the connection part 3 connecting a back bottom 1 and a waist bottom 2, first and second connection holes 8, 9 are respectively provided to the second protruding piece 6 on the side of the back bottom 1 and the third protruding piece 7 on the side of the waist bottom 2 and both bottoms are connected by selectively inserting a connection pin 10 in the first and second connection holes 8, 9. The position (A) of the first connection hole 8 is present on the same axial line in the width direction of the bottoms as the stop place of the support arm 5 for supporting the back bottom 1 and a first protruding piece 4. The position (B) of the second connection hole 9 is present at the position close to the waist bottom 2. By this constitution, the back bottom and the waist bottom can be changed over so as to be independently moved or cooperated. |
