Hoist Gate Operator

A shuttering machine is a specialized lifting equipment used for opening and closing gates (silt traps) in hydraulic structures. Like general-purpose cranes, it is a cyclic interval lifting machine. As a special-purpose crane, the shuttering machine has the following characteristics:

Large load variations occur. The previous chapters have introduced the calculation of gate opening and closing forces, which include the weight of the gate leaf, rolling friction, counterweight or water column pressure, lifting force, and downward suction force. All of these forces except the weight are related to the water pressure the gate withstands, and this water pressure varies with the movement of the gate leaf. Therefore, the load on the opening and closing mechanism is continuously changing, with a large range and unevenness. For instance, when the gate falls to close, the load on the flexible components of the opening and closing mechanism may drop to zero, meaning the gravitational force of the gate and its accessories is insufficient to overcome the frictional resistance, and additional counterweights or rigid rods must be used to apply closing force and push the gate down. In some cases, if the gate gets stuck during the lifting process due to unforeseen reasons, the maximum load may exceed the originally designed rated load.