1.This paper presents the structure, working principle and screw type selfadjusting unit of the brake unit of an Italian ASTRA dumper modelBM304F. Also structure, working principle and clearance adjusting method of the brake shoe and brake drum of hand brake are presented.
2.Lifting and dropping of the mechanical arm are realized through ball screw driven by gear motor with belt brake, meanwhile, double security protection is applied, namely, at normal operation limit, the proximity switch is adopted and at upper or lower limit, the stroke switch is available.
