国上泽大大李 Torque Loading-Basic Terms 3 .To raise the load-tighten a screw or bolt >P must push the load up the incline >a frictional force will work against it. .To lower the load-loosen a screw or bolt >P must push the load down the incline >The frictional force will work against it,so in the opposite direction than before. a 47 圈上大峰 Torque Loading-Load Raising3 (Tightening screw) Summing the forces in vertical and horizontal directions gives: Z FH =P-N sin -fN cos=0 ΣFy=F-Ncos+fN sin2=0 f-frictional coefficient47 Torque Loading - Basic Terms 3 •To raise the load – tighten a screw or bolt P must push the load up the incline a frictional force will work against it. •To lower the load – loosen a screw or bolt P must push the load down the incline The frictional force will work against it, so in the opposite direction than before. 48 Summing the forces in vertical and horizontal directions gives: FH = P - N sin  - f N cos  = 0 FV = F - N cos  + f N sin  = 0 f — frictional coefficient Torque Loading-Load Raising3（Tightening Screw）