一、 General introduction

FKDX-HZ ring load lifting limiter is safety device used for tower crane and other kinds of lifter, which protect tower crane safe operation by limit Max. lifting capacity and Max. lifting capacity of relative hoisting speed, which applies with GB5144-1994 and GB6067-1995 standard and design requirements.

二、 Working principle

FKDX-HZ series ring load lifting limiter is made up of proving ring, micro travel switch and pulley. Elastic deformation of proving ring under tension forces cambered plate, which causes relative displacement between micro travel switch contact and governing screw, the displacement make a electrical signal. Debugging governing screw can process limit load needed.

三、 Main technical parameters

1. Load limitation scope ： 5KN-80KN (single ring)
2. Repeat accuracy: 2.5%
3. Supply interruption scope: 100% － 110% (tunable)
4. Pulley outer diameter: Φ150 、 Φ256 、 Φ330 、 Φ400 (pulley may be made to order of user)
5. Environmental temperature: － 20 ゜－ + 60 ℃

 

四、 Assembly

1. Single ring installs on tower crane lifting jib upper chord end, type of attachment may be decided by user according to practical situation, and please find following proposal for reference (shown in fig 1)

2. Double rings limiter installs on tower crane slewing tower. Installation position may be decided by user after debugging, pulley adapted to stress ring may be used instead of lifting jib guide pulley, and please find following proposal for reference (shown in fig 2)
 

 

五、Debugging  

Assembly ring weight limiter to appropriate position of tower crane (no interference to steel structure), debug according to working situation with testing weight. Adjust regulating screw according with requirements and lifting 3 times for each working situation, and lock check bolt after limit position determined. User may start normal work after above operation, and please find following debugging method:
    1、Adjusting of Max. lifting load switch: (within Max. radius of Max. lifting load)
   （1）Lifting rated Max. lifting load in low speed
　 （2）Adjust regulating screw till its head touch micro switch
　 （3）Add 10% to the lifting load and lift in low speed, repeat adjusting if the added load can be lifted.
　 （4）Tighten check screw
    Validate middle lifting speed for rated Max. load is available after adjusting.
    2、Adjusting of stepping weight limit switch (50% of rated Max. lifting load)
   （1）Lifting load in low speed and shift to high speed
   （2）Adjust regulating screw till its head touch micro switch
   （3）Add 10% to the lifting load and lift in low speed, then shift to high speed, repeat adjusting if high speed available.
   （4）Tighten check screw
    3、 Adjusting of 90% rated Max. lifting load early warning switch
   （1）Lifting 80% of rated Max. lifting load in low speed
   （2）Adjust regulating screw till its head touch micro switch
   （3）Add 10% to the lifting load and lift in low speed, repeat adjusting if the added load can be lifted.
    4、Tighten check screw
   Notes: Loading range of lifting load limiter is between rated lifting load of relevant working situation and 110% of rated lifting load, middle value of the two may be used for debugging.

六、Care and maintenances
    1、Tower crane driver must know principle, function and debugging of FKDX-Z very well. The driver must do pre-inspection and function test before operating.
    2、All rotatable parts and sliding parts must be lubricated regularly, and all fastening parts must be inspected and tightened regularly.