How to select gravity roller for roller conveyor?

Gravity roller’s strength is different by conveyed product’s bottom side material and loading impact force.

1) Gravity roller loading weight calculation formula.
     (A)Conveyed product’s bottom is hard and not deformed(for example, steel,plastc)
          Gravity roller loading weight for 1 pc=conveyed product(1 pc)/2.

     (B)Conveyed product’s Bottom is flexible.
          Gravity roller loading weight for 1 pc=conveyed product(1 pc)/(conveyed product contacted roller quantity-1)
 

 2) If loading impact force exist, please multiply by below coefficient(N)     

Loading Impact ForceExampleCoefficient(N)
not existonly conveyed product1
a littleLoaded slowly by hand1.5
a little strongLoaded by forklift1.5~2
StrongHoist,Crane2~3
Loading from people’s shoulder3

    (A) If  loading impact is imposed  evenly on rollers(above 4 pcs).
          Gravity roller loading impact for 1 pc=Gravity roller loading weight for 1 pc*Coefficient(N).

  (B) If loading impact is imposed on only one pc.
        Gravity roller loading impact for 1 pc=Conveyed product Weight*Coefficient(N).

 3) In case of double tracks’ roller conveyor.
      Because supporting rollers is increased, so roller conveyor can convey normal weight’s 1.5 times to 1.8 times.
      (Normally, conveyed with pallet).

 4)  Roller’s strength.

      1 pc roller’s strength>=1 pc roller’s loading weight*Coefficient(N).