NJ(NYD) contact type wedge holdback (hereinafter referred to as “holdback”) is a type of contact type anti-reversing device installed on the low speed shaft of the reducer or pulley shaft, compared with conventional holdback (roller holdback etc.), it has the advantages of big brake moment, reliable drive force, easy release, convenient installation (the requirement for installation accuracy is not high), it is composed of several wedges arranged in certain pattern between the raceways formed by inner race and outer race, when the inner race rotates in opposite direction, under the action of spring force, the inner race and outer race are wedged into an integral part so as to bear the holdback moment (see Fig. 7), it is widely used on the equipment with holdback requirement such as belt conveyor, bucket elevator etc. 

The service environment of NJ(NYD) holdback complies with the provisions for service environment of NJD(DSN) low-speed holdback.