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JACKE-49Shaft supporting length Lshaft end freeJack fixed15001250100075050040030025020015010075502510251100Graph1 fixed-freelySizenf =1/450010000500020001000kNAxial direction loadAxial Supporting length(㎜) Allowable axial direction loadScrew jack, depend on application, must preventeffect of buckling on screw, there is limitation ofapply of the axial direction load.Allowable buckling-load can be calculated by thefollowing formula.W=nf・π2・E・Ⅰ・α(Eulers formula)L2W:permissible buckling load (N)E:vertical modulus elasticity factor 2.06×105(N/㎜2)Ⅰ:minimum sectional secondary moment of screw shaft(㎜4)Ⅰ=πd464d:screw shaft root diameterL:shaft supporting lengthnf:factor by installation methodFixed-freelynf=1/4(0.25)Supported-supportednf=1Fixed-supportednf=2α: safety factor 0.25Example of calculationJack size JTA050From the basic specification, screw shaft rootdiameter d= 31.5(㎜), minimum sectional secondarymoment of screw shaft.Ⅰ=π×31.54=48329(㎜4)64The shaft supporting length L= 1000(㎜)Installation method: fixed-freelyPermissible buckling load is:W=0.25×3.142×2.06×105×48329×0.2510002≒6135(N) = 6.1(kN)In addition, in the case of permissible buckling loadexceeds nominal capacity, the permissible axialdirection load should be limited to nominalcapacity, the permissible axial direction loadshould be limited to nominal capacity.

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