武汉某装卸公司钢坯料场龙门吊车额定起重量为20t,平时用钢丝绳套住4～8根钢坯起落。以往装卸和堆积钢坯时,是由人工握住吊钩,拉动吊钩下的重物,扳转一定角度,待放稳后才能放下手中吊钩。一天日夜三班作业,劳动强度大,工效低,操作紧张,很不安全。经革新后改为电动旋转吊钩,见图。 Wuhan, a loading and unloading company billet yard gantry cranes rated lifting capacity of 20t, usually with wire rope sets of 4 to 8 billet landing. In the past loading and unloading billet, it is manually hold the hook, pulling the weight under the hook, pull a certain angle, to be stable before you can put down the hook. Day and night three shifts a day, labor-intensive, low efficiency, tight operation, it is not safe. After the reform to electric rotary hook, see figure.