| 摘要 |
1,236,029. Mining machines. GREENSIDE MACHINE CO. Ltd. 3 Feb., 1969 [9 Feb., 1968], No. 6655/68. Heading E1F. [Also in Division F4] A roof shield for a mining or tunnelling machine comprises ducts 6 extending the length of the shield and through which dust laden air is drawn from the cutting face to the rear end 2 of the shield. Each duct 6 is connected by a flexible pipe 8 to a blower 9 or to a blower common to all the ducts and through a pipe or pipes 10 to a dust extractor. The ducts may be integral with or separate from the shield. In another emodiment, a central section 3 of the shield is also provided with two ducts 6. The shield may be constructed as described in Specification 1,133,109. |
