Also known as the upgrade limit position limiter, that is, when the tower crane hook rises to the limit position, the rising power supply of the lifting mechanism is automatically cut off. The mechanism can be used for descending movement, and action test verification should be done during security inspection.
Variable limiter:
(1) Variation of the car. The tower crane adopts a horizontal arm frame and hangs heavily on a crane, depending on the horizontal movement of the car on the arm frame to achieve variation. The variable amplitude limiter of the car is to use two-stroke switches and buffers installed on the head and root of the lifting arm to limit the running position of the car.
(2) Dynamic arm variation. The operating radius(amplitude) of the tower crane transformation is realized by changing the elevation angle of the lifting arm. The light signal is transmitted to the instruction plate of the driver's cab through the change of the contact point of the device.It also indicates the number of elevation angles. When the elevation angles of the control arm are respectively at the upper and lower limit levels, the lower limit switches are respectively pressed to cut off the power supply to prevent the tower from instability caused by exceeding the elevation angle.
There is no derailment accident during the control operation of the rail tower crane. During the security check, the walking action test of the tower crane should be carried out, and the reliability of the collision limiter should be verified.
