Size Fr Max. (N) @ Ta Max. (Nm) M0 70 1.5 M1 100 3.4 M2 200 7.1 M3 300 18 M4 500 38 M5 800 93 M6 1300 240 M7 2100 340 M8 3100 570 7 19100 x P 2 x Ta Dmin = ------------------- = ------------ (m) Fr Max. x n Fr Max. P = Power rating (kW) Fr Max. = Maximum radial force (N) (see table, left) N = rotating speed of input shaft (rpm) Ta = Driving torque (Nm) Radial Loads TEL: 01827 288122 sales@wmh-trans.co.uk FAX: 01827 253390 www.wmh-trans.co.uk WMH screw jacks have rated radial forces that can be applied to the input shaft of each jack. These have been calculated for Ø ~ 30° or 330° as these are the worst case scenario for the bearings based on lifting force and rotation direction. Although most applications use flexible couplings or cardan shafts to connect the screw jacks to drive motors, it is possible to mount and provide power via spur gears, sprockets and / or pulleys directly mounted to the input shafts of the screw jacks. In this scenario, it is even more crucial to pay close attention to the rated radial load capacities of each screw jack being used. A formula for calculating max power, torque and speed is provided below: Permitted radial force (Fr) on application of force in L/2 Minimum diameter (D) for spur gear or pulleys: