| 摘要 |
1526702 Tunnelling machines C GRANDORI 18 Jan 1977 [2 Feb 1976] 01961/77 Heading E1F A grid 11 is so rigidly secured to the front of the cutting tool-carrying, rotary head 1 of a full face, tunnel-boring machine that the cutting tools 3 only slightly project ahead of the grid through the openings therein, these openings have a size corresponding to the optimum dimensions of fragmentation of the material being mined by the machine for passage to the rear of the machine. Preferably the grid consist of a set of annular bands 11 disposed concentrically of the axis of rotation of the head and extend over the entire surface of the head. The bands may be subdivided into sectors located either between the spokes of an open type cutter head as shown in between the radial arrays of cutter tools on the front surface of a closed type cutter head. One or more of the sectors of such a grid may be removable from the head to allow of access from behind the head to the front of the head. |
