目前作业过程中,起下油管经常使用的吊卡是活门或月牙吊卡。吊卡手柄销子在来回开启、关闭过程中时常发生倒扣脱落现象。操作人员在上、卸油管丝扣时,极易发生月牙吊卡突然开启,油管从高处落下伤人;特别是冬季作业更容易发生吊卡手柄销子倒扣脱落现象。因此,设计、使用吊卡防掉 At present, the operation process, from the tubing often used elevator is the valve or crescent elevator. Elevators handle pin back and forth in the opening and closing process often happen inverted buckle off phenomenon. Operators in the unloading pipe threaded, prone to a sudden opening of the crescent elevator, pipe fell from the height of the wounding; especially in winter is more likely to happen elevator handle flip down the phenomenon. Therefore, the design, use the elevator anti-off