| 摘要 |
PURPOSE: A height adjustable manhole is provided to reduce manufacturing costs by recycling the manhole by controlling the height of the manhole according to the height of concrete which is poured on the ground. CONSTITUTION: A height adjustable manhole comprises an indoor piping(10) and an outdoor piping(20). The indoor piping comprises a settling protrusion on the top. The indoor piping comprises the guide groove on both sides and a plurality of multi-layered grooves in the outer circumference. The outdoor piping comprises a guiding bump to be meshed with the guide grooves to move up and down. |
