Tower lift hoist must be equipped with five stopper

(A) from the weight limiter
Also known as the overload limiter, is a way for lift hoist operation without overload safety device, when more than nominal weight lifting, the lifting mechanism can

automatically cut off the power to stop or alarm. Lifting limiters with mechanical and electronic two.
(2) the torque limiter
For luffing lift hoist, lifting a certain extent only allow certain hoists, if overweight, since there is emphasis on the danger of tipping. Torque limiter is developed

according to the characteristics of a protective device. In a certain extent, if suspended matter exceeds its corresponding weight, the circuit is cut off, the lift can not

ensure the stability of the lift hoist. Torque limiter with mechanical, electronic and composite three.
(3) height limiter
Also known as the hook height limiter. Are generally mounted on the head of the boom, when raised to the limit position the hook slide, then hold the lever. Pressure limit

switch, cut off the circuit stop, and then closing, the hook can only decline.
(4) stroke limiter
Prevent or limit the lift hoist crash occurred within a certain range with safety device. It is generally installed on the active trolley inside, is to install a pull to the

trip can toggle switch. The other end of the track (in the running position defined) limit position of installation of a fixed baffle, when the lift hoist operation to this

position, the limit switch trip baffle that pull the touch, the power cut-off control of walking, and then close the gates lift hoist only run in the opposite direction.
(5) the amplitude limiter
Also known as the amplitude or magnitude limit indicator, the general boom lift hoist lifting arms are hung in a range indicator. It is composed of a fixed circular dial,

mounted in a vertical center of the disk activity indicator. When the amplitude, the pointer indicates the various amplitudes under the rated capacity. When run to the upper and

lower arm when the two extreme positions, namely pressure limit switch, cut off the main control circuit, luffing motor stop, to limit the role.
From the weight limit, torque limits, height restrictions, travel restrictions, amplitude limit, that limit tower five. A new generation of tower lift hoist black box basically

have these five functions, and can expand wind detectors, some of the black box also has tower Rope hoist anti-collision system functions.