The single rope skip buckets for vertical shafts are commonly used in small and medium-sized mines, as well as shallow wells. In China, the vertical shaft single rope coal lifting buckets used in coal mines are standardized by their nominal carrying capacity, available in 3, 4, 6, and 8-ton models. They are primarily composed of a frame, bucket box, gate, suspension device, guiding device, and roof. The frame forms the main structure of the bucket, made of steel sections and plates. The bucket box is designed for coal loading, also made of steel plates, with the top serving as the coal loading opening. Beneath the opening, there is an adjustable coal slide plate to adjust the position of the coal drop point within the bucket box. The bottom of the bucket box is the coal unloading opening, equipped with additional lining plates on the bottom board to mitigate the impact and wear on the board during coal loading and unloading. The gate is a critical component for controlling the unloading process, requiring reliable operation and quick unloading.
The gate of a single rope skip mainly consists of two structural forms: the curved track linkage under-open gate and the side bottom unloading fan-shaped gate. When the curved track linkage under-open gate is in the normal closed state, the linkage line forms an angle with the vertical position, creating an automatic lock. As the skip is lifted towards the unloading position, the unloading roller on the gate enters the unloading curved track, where it is opened by the action of the curved track. After coal unloading is complete, the skip is lowered, the unloading roller exits along the unloading curved track, closing the gate and reaching the locked position. This type of gate mechanism is simple, requires less effort to open, exerts minimal force on the shaft, and has a short unloading curved track, but sometimes the locking mechanism may fail due to incomplete coal unloading, causing the gate to open automatically during the lifting process, leading to accidents. The fan-shaped gate on the side bottom unloading is opened by the skip being lifted towards the unloading position, where the roller enters the unloading curved track, operating the fan-shaped gate through the linkage to open it, while extending the bottom plate of the skip for unloading.
After unloading, the skip is lowered, the roller gradually exits the curved track, and the sector gate falls under its own weight, pulling the bottom plate of the sieve back. This type of gate requires low investment and is easy to maintain, and was widely used in Chinese coal mines. However, the gate's opening subjects the shaft frame to significant stress and results in a large amount of spilled coal, so it is rarely used in new mine construction. It features a movable cover plate welded to the frame at the top of the skip box, with one end hinged to the side plate of the skip opening by a pivot pin. The cover plate is usually in an inclined position, serving as a coal挡 during loading. In case of necessity, the cover plate can be lowered to seal the top of the skip box, allowing for the lifting and lowering of personnel, materials, and equipment. The ceiling is a structure of I-beams and steel plates, installed on the top of the frame, providing protection against water leakage and safety, enabling maintenance personnel to stand on the ceiling for rope adjustment and inspection of the skip guides.
