Machines for positioning roof supports in a tunnel

摘要

The present invention is directed to a machine for positioning roof supports in a tunnel. The machine includes a body unit having a track engaging assembly by which the body unit may be suspended from an overhead track extending along the length of the tunnel. A drive motor is provided for impelling the body unit along the track. An arm assembly support member is mounted on the body unit for pivotal movement about a vertical axis under the control of a slewing actuator. In addition, an arm assembly is pivotally connected at one end thereof to the arm assembly support member for pivotal movement about a horizontal axis under the control of a lifting actuator. A yoke holder is mounted at the opposite end of the arm assembly so as to maintain a constant attitude during the raising and lowering of the arm assembly between a lowered position and a raised position of the arm assembly. Lastly, a yoke is provided for supporting a roof support and pivotally mounted to the yoke holder for pivotal movement about a vertical axis under the control of a pivoting actuator and control member to control actuation of the pivoting actuator and the slewing actuator so that movement of the arm assembly from a slewed position in which the arm assembly is in the lowered position and transverse to the length of the tunnel and the yoke is parallel to the length of the tunnel and adjacent a wall of the tunnel to a lifting position in which the arm assembly is in the lowered position and lies along the length of the tunnel with the yoke normal to the length of the tunnel includes two movements. One from the slewed position to an intermediate position during which the slewing actuator and the pivoting actuator are operated together to pivot the arm assembly while pivoting the yoke to maintain the yoke parallel to the length of the tunnel. A second movement is from the intermediate position to the lifting position in which the slewing actuator and the pivoting actuator are operated together to pivot the arm assembly to the lifting position while pivoting the yoke in a return movement to a position in which the yoke is normal to the length of the arm assembly. This movement of the yoke permits a roof support to be placed on the yoke in the slewed position while maintaining it out of contact with the tunnel walls during movement from the slewed position of the arm assembly to the lifting position.