| 摘要 |
<p>The structure is movable by hand power and has a supporting frame with wheels, being for an internal transport trolley, mobile stepladder etc. Near each wheel (2) are one or more protrusions (5) extending towards the ground (7) and ending just short of the latter, so as to support the frame in a lower position in the event of wheel breakage. There can be two protrusions for each wheel, one on each side, or where it is a caster wheel one can be fixed to its swivel bracket. The design protects against sudden tilting or instability, particularly when transporting dangerous materials etc.</p> |
