| 摘要 |
A right side frame member has a locking pin. A left side frame member has a pivotal locking member with multiple locking positions for engagement with the locking pin. The combined length of the right and left side frame members can be varied. At least two antiskid members are disposed at each of the radial outer end portions of the right and left side frame members. The antiskid members are provided with studs for improving the traction. The studs are disposed at the middle of the antiskid member and are longer than those disposed above the side. The length of the right side frame member is separately and additionally adjusted so that the device can be further adjusted for all type sizes.
|
