| 摘要 |
PROBLEM TO BE SOLVED: To enable selection between regulation and non-regulation of wheel rotation when seating. SOLUTION: When an operation lever is turned to a free position, an operation body 28 is rotated to position a step portion 33 of an working body 32 forward, and a bottom surface of the working body 32 contacts a front upper surface of a supporting body 18. The working body 32 is interposed between a wheel 2 and a frame 1 via the supporting body 18, and downward movement of the frame 1 and a moving body 15 due to seating load is prevented. Therefore, a tooth 16 of the moving body 15 is not engaged with an engaging portion 14, and a wheel 2 rotates freely. On the other hand, when the operation lever is turned to a lock position, the operation body 28 is rotated to position the step portion 33 of the working body 32 backward. A space for the frame 1 to move downward is formed between the bottom surface of a large diameter portion of a storage portion and the step portion 33 and a front upper surface of the supporting body 18. Therefore, the frame 1 and the moving body 15 are moved downward by seating load, and the tooth 16 of the moving body 15 is engaged with the engaging portion 14 to regulate the rotation of the wheel 2.
|
