| 摘要 |
The manhole or gully grating comprises a frame 10 and at least one removable cover part 14 or grating part, the or each part being hinged to the frame by a hinge, the hinge comprising a boss 42 on the frame and a formation on the part to enable the part to pivot on the boss. The formation comprises an arm 68 with a lower flat surface and the boss has an upwardly facing flat that is at an acute angle to the horizontal so that when the part is pivoted up from the closed position, the part can be pulled in the direction away from the boss so that the lower surface of the part at the end rests on the upper surface of the frame and the flat surface of the arm is parallel to and slides on the flat on the boss so that the part can be removed by sliding. The flat on the boss is preferably at an angle of around 10 degrees while the lower flat surface is designed to be substantially horizontal when the cover/grating part is closed. The formation may comprise a second flat 78 at 90 degrees to the first so that when the part is in the open position the second flat lies on the flat on the boss. The formation may also include a second arm 66 to form a fork which receives the boss and the frame may include an element 46 behind which the second arm of the fork drops when the part is opened beyond vertical so as to inhibit movement back towards the closed position. |
