| 摘要 |
850,170. Roof support advancing systems. GEWERKSCHAFT EISENUTTE WESTFALIA. Jan. 25; 1957 [Jan. 27, 1956], No. 2808/57. Class 20(2) The frame assemblies of a roof support advancing system each comprise two support frames connected to a shifting device between the frames by members resilient in the vertical sense, which together with supporting brackets on the outside of the frames give lateral stability during movement. Props 1, 2 and 4, 5 are joined together at the floor end by resilient bars 3, 6 and are also provided each with a projecting bracket 7 and stud 8. Straps 12, 11 connect the prop frames to a piston rod 10 and the cylinder 9 respectively of a shifting device. Resilient extensible struts may also connect the frames at the roof end. |
