| 摘要 |
535,621. Manhole covers. HARTLEY, C. J. Oct. 17, 1939. No. 28029. [Class 107] A manhole cover and frame of the kind in which two triangular shaped covers 16. 17 are mounted back to back in the frame 10, each cover being supported at three points and adapted to open about an axis across the centre of the frame, has a removable cross bar 15 disposed across the frame between the backs of the covers and against which the covers abut, the ends of the cross bar being fitted in flattened portions of the frame, which accomodate the dual seats at the adjacent ends of the covers. The cross-bar may be of T or other bulbine section, and the ends of the covers may slide as the covers are raised. Specifications 390,806 and 474,250 are referred to. |
