To reduce timf of seeking and changing fixtures,thus assuring quick installment

and uninstallment of fixture and reducing labor use.

To assure orderly placement of heavy items like fixture without occ-upying too

much room.

Thebering of weight of eachply of shelly board is 800kg the beari-ng of overhead

traveling crane is 800kg it can slide horizontally.

It can be re-joined and re-installed as per size field thus assurina easy installment.