or tubes are provided with the spill plate for guide the cutting machine. For instance, a guide tube is provided for the shearer, a guide channel for the hook plow; and a face-side guide tube for haulage chain and a gob-side guide tube for the stabilizing bridge arm of the sliding plow.
B. Ramp Plates
The ramp plates are mounted on the face side of the pans. They are used to scoop up the remnant coal on the floor when the conveyor is being advanced. This way, it ensures that the conveyor is always advanced to the predetermined position thereby allowing the shearer or plow to cut a full web. It must be noted however that the ramp plate cannot be used as a major coal-loading device. If there is too much coal left on the floor in front of the conveyor, the ramp plate may climb up during conveyor advance, allowing the coal to slip under the conveyor. As a result, the conveyor will lean toward the gob side, the shearer or the plow will climb up and leave the bottom coal, and in severe cases it may cut into the roof or the support canopy.
There are many types of ramp plates. The most commonly used ones are the linear, the bending, and the curved shape. The bending shape consists of two sections with different slopes. The lower section has a smaller slope for better scooping action. The curves ramp plates are used mostly for the sliding plow.
2-5 Chain Units
The chain unit consists of the link chains and flight bars. The link chain is usually denoted by its diameter and nominal pitch [25], such as φ228
