| 摘要 |
1375202 Making expanded metal EXPAMET CONTRACTS Ltd 8 March 1972 [10 March 1971] 6473/71 Headings B3A and B3W [Also in Divisions H5 and E1] Electric heating elements to be embedded in a roadway, e.g. between layers of asphalt on a concrete foundation-comprise rectangular mats of expanded metal each having two terminal bus bars and each of which is manufactured with a transverse curvature so that during installation it may be held flat against a road base 5 by central fixing 6-e.g. of mastic-without the need for edge fixings. Each mat, shown with a bus-bar 7 and cable 8, may be 20 feet long, 7 feet wide and have a curvature giving a central rise of 3-4 inches. The curved mat may be produced on a vertically reciprocating knife machine, Figs. 3, 4 (not shown), having its upper knife (9) bent relatively to its carrier (10) by central shims (12) so as to be convex, in the plane of cut, towards the lower knife (11). |
