| 摘要 |
Apparatus for controlling the position of a mineral mining machine, such as a plough, guided for movement along a guide comprises inclined piston and cylinder units connected via ball-and-socket joints between connectors at the ends of elongate beams guided on roof supports and brackets on a conveyor forming or supporting the guide. The cylinder of each unit has a ball at its upper end received in a socket on one of the brackets. This upper ball has a stepped profile with a shoulder and an end region of different radii of curvature. The piston and interior of the cylinder are also stepped with innermost regions of reduced diameter. These measures reduce the overall length of the unit. |
