Roller Backstop Device .

ND (also designated NJ, NYD) are Tianiu roller-type contact backstops for low-speed shafts: a compact, light design with torque arm, reliable engagement, smooth freewheeling and modest mounting accuracy requirements. 17 sizes from ND16 to ND7000: backstop torque 1,600–700,000 N·m, bore 50–450 mm (H7, shaft h6, key to GB/T 1095-1979), inner race speed up to 150 rpm for small sizes and up to 50 rpm for large ones. Up to ND380 the torque arm is a single plate, from ND500 a double plate. The arm rests against a stop with axial and radial play and must not be clamped.