Patent GB-564643-A (GB)
Title: Method of and means for tunnelling
IPC: E21D9/10
Filed: 1943-02-22
Abstract: 564,643. Tunnels and tunnelling. AYERS, F. P. Feb. 22, 1943, Nos. 2911 and 9850. [Class 85] Tunnelling is effected by starting a boring, lining it as far as possible with a lining having a helical track on its inner face, mounting a supporting frame for, a rotary cutter on said track, rotating the frame so that it runs on said track to advance the cutter into the working face, and continuing the lining behind the cutter and in advance of the supporting frame so as to extend the helical track. The lining may be built of pre-formed arcuate sections of iron, concrete, &c., each formed centrally, along the edge or otherwise, with a length of track, and with a recessed inner face providing rims 2, Fig. 7, for connection of the sections ; the outer surfaces of the sections and of the rims may have grooves, pockets, &c. into which cement &c. may be injected through holes in the sections. The sections may be rhomboidal and laid with one edge parallel' to the tunnel axis, or rectangular and laid with the edges inclined to the tunnel axis, or they may be rectangular with projections 7, Fig. 7, on opposite ends of opposite sides, such sections being assembled end to end circumferentially of the tunnel so as to give a spiral advance ; the sections are of such length that adjacent circumferential runs break joint. The track portion of the section may comprise a groove or a grooved rib or a V-section or like rail 3 ; the end rims of the sections may have cutaway parts 4 adjacent the track. The lining may also be formed in situ by rotatably mounting a roll of sheet metal in a rotary shield carrying the cutter so that the sheet metal is laid helically against the tunnel wall in abutting turns which are connected as by fish-plates and supported by segments of section iron forming the track ; in another form, the sheet metal is replaced by expanded metal or the like on which a quick-drying concrete lining is cast, the tracks being formed thereon. A flat base may be formed in the tunnel by pre-cast sections 8, Fig. 3, engaging rims 2 of the sections and further supported by feet 9 with grooved &c. ends engaging further rims 2. The cutter supporting frame 14, Figs. 1 and 2, has at three points a pivoted &c. shoe 10 with wheels engaging the track ; this three-point support may be multiplied longitudinally of the tunnel to engage various turns of the track. The frame 14 may be rotated around a stationary shaft 13 by worm gearing 17, 18, driven by hand or by a motor 19, the rear of the shaft 13 being adjustably supported, to allow for curves in the tunnel, in a framework 16 clamped by jacks 24 and provided with pairs of cheeks 23 engaging the arms of a spider 22 ; the shaft 13 may be hollow, and a pilot drill may be contained therein. In another form, the shaft 13 rotates with the frame 14, which carries a cutter 20 rotated as by a motor 21. The working face may be supported by a shield 29, Fig. 13, with a helical front wall 25 and a tubular casing 26 housing the cutter head 20. An elevating device 30, 32, Fig. 1, may be rotatably supported on the shaft 13 and used for placing liner sections.