| 摘要 |
A travelling face support has an attached extensible shield which, besides providing the means of shoring up the roof of the seam and providing a connected coal cutting shield, has both a packing shield to protect the coal cutting area and a floor beam. One or more pull-back cylinders act upon a supporting frame divided into sections along its length. A continuous recess, transverse to the direction of the prop conveyor, is provided in each section of the supporting frame to receive a forward longitudinal section of the corresponding floor beam. A lifting device, which is supported on the prop floor, is fixed in a recess of a section of the supporting frame in the rear part of the extensible shield beneath the coal cutting shield. The lifting mechanism of this device is used to control the position of the forward longitudinal position of a heel plate of the supporting frame section.
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