| 摘要 |
<p>Travelling inverted 'U' section shuttering for reinforced concrete tunnels has a retractable longitudinal strip or plinth at the base of the vertical members secured by pins is retracted by swinging up a hand lever from the horizontal to the vertical. The plinth permits the shutter to be struck and lowered onto rollers, and the design avoids taking the weight of the shutter on the tie plate pins. The plinth may be an angle iron with an edge rebate giving positive alignment with the base of the uprights. The tie plate may be pinned to two plates which are welded to the plinth and the base, and may incorporate the hand lever. The plinth may be locked by a cotter in alternate plates holes.</p> |
