GB472760A - Improvements in or relating to covers and frames for manholes and the like - Google Patents

Abstract

472,760. Road surface boxes. ELKINGTON, V. March 27, 1936, No. 9144. [Class 107] A manhole cover 10 fitting closely within its frame and resting upon horizontally projecting parts c thereof, has inclined edges, and one pair of opposite sides at least of the cover and frame are inclined in a similar sense. Thus, as indicated in Fig. 2, a section through the cover perpendicular to the said opposite sides 19, 20, is roughly in the form of a parallelogram the angles of which are not right angles. The other two sides of the cover may also be inclined in a similar sense or they may be inclined in opposite directions. The sides may be plane or curved, or again, each side may consist of an upper part a and a lower part b, the lower part having a greater inclination to the vertical than the upper part. The frame consists of four sections 23 . . 26. Fig. 1, which are channelled as shown and, which are strengthened by cross webs 27. In assembling the frame, the sections 25 and 26 are first placed against the cover and then connected by bolts to the other sections 23, 24, the bolts passing through elongated holes in cross webs near the ends of each section. Hard lead or other keying metal is then run into the chambers 30, Fig. 1, formed between the various frame sections. The cover may be filled with concrete or wood blocks and the frame sections are concrete filled preferably by being pushed down into a bed of concrete. The trench cover, Figs. 5 and 6, is formed of cover parts 10a, 10b, 10c and frame sections which are substantially similar in construction to the manhole cover shown in Figs. 1-2. The cover parts vary in size within a few thousandths of an inch and the parts 10b, 10c are in part supported by one side of the adjacent cover parts 10a, 10b, respectively. The cover part 10a and its frame sections 23, 25a, 26a, are first assembled and the frame sections 25b, 26b and the cover part 10b mounted in position. The remaining cover parts and frame sections are added in succession. The frame sections of the trench cover, and of the manhole cover above described, are ground off to the exact length if originally too long and are made up to the exact length by the keying material if too short. To facilitate removal, the covers are fractionally wider at one end than at the other.