20T Truck Crane Lifting Mechanism
Lifting mechanism is consist of hydraulic motor, decelerator, brake, steel wire rope, sheave etc.
There are two parts main and aux. Winches for the lifting. For this truck crane, the main and auxiliary winch are the same structure(only the length of the wire rope is different), the operation level is the same.
Stop: push the main winch joystick back to the neutral position and the object stops lifting.
There is balance valve in the hydraulic system, to keep smooth lifting and make the object stay in any position.
The main winch is for the main boom. When the main boom is working, as the boom extended, the lifting height increases, the wire rope length is not long enough. You can change the wire rope ratio. Be sure to install the height limit weight.
When the system pressure reaches the brake opening pressure valve. The normal-closed brake opens, piston moves, brake released, the output shaft of the motor passes through the deceleration device, drives the reel fixed to the rotate to achieve the lifting function.
When the system pressure gradually decreases, the brake piston gradually returns to its original position, press the friction plate, rotation stops to achieve the braking kinetic energy.
The working principle of declining is basically the same as that of lifting (motor rotates in reverse).
1) Choose the appropriate wire rope ratio according to the boom length. It is necessary to lower the object and unlock the wire rope completely if the hook rotates due to the wire rope rollings.
2) The number of wire rope loops on the hoist drum must not be less than three circles in any lifting condition.
3) When hoisting, lift the object off the ground for a while to make sure there is no safety hazard.
4) Before the object load off the ground, it is not allowed to lift from the ground by extension boom, only the lifting operation can perform.
5) Do not sharply change the joystick from “Lift” to “Drop” or from “Drop” to “Lift”. During the conversion, the handle should be returned to the neutral position, and after confirming that the reel stops rotating, continue the operation; otherwise, the mechanism will be damaged.
6) The slings should have sufficient strength, the lifting weight includes the weight of hook and slings.
7) Do not lift with high speed with loaded.