The portable roller stand for supporting boards ejected from a wood planer is designed with a micro- fine height adjustment produced by turning the knurled knob of the adjusting screw with a torque M. The single-thread screw with square threads has a pitch p (advancement per revolution) and is threaded into the collar at B to control the distance between A and B (and hence C and D). The roller E and supporting box have a mass m1, and the four uniform links (two on each side) have a combined mass m2 and a length 2b for each. Neglect all friction and find the torque M necessary to raise the roller for a given value of ().
