直心力骨式茄子在线观看视频把左旋、右旋的螺线交互编入，并以直心力骨连接，力骨距未满螺距两倍的称为A2，力骨距大于螺距的称为F2。
Left-wound and right-wound spirals are alernately Arranged and jointed with sraight rods.If rod pitch Is less than tw0-fold spiral pitch,belt is called A2. If rod pitch is equal to or greater than two-flod spiral Pitch,belt is called F2.

Advantages
1. 表面平滑，可搬送不稳定的制品
Surface is flat and unstable itens can be carried.
2. 允许张力大，可搬送重负载物
Allowable tension is high and heavy load can be Carried.
3. 可用于高温情况
Belt can be used at high tiemperature.
4. 网目细小，所以可搬送小物品 
Belt can have tight mesh and can carry small Items.

Typical specification of F2(nominal size) 
规格Specification       重量Weight(kg/m2 ) 
F2-8.5-30-6.0-4.0              43.5
F2-7.5-26-4.0-3.2              28.4
F2-6.0-20-3.2-2.6              14.8   
F2-4.2-15-2.6-2.0              20.2 
F2-3.4-14-2.0-1.4               20.2  
F2-3.0-12-1.8-1.4                20.2   
F2-2.6-10-1.6-1.2                11.4 

规格Specification       重量Weight(kg/m2 ) 
A2-9-16-4.0-3.2          30.5
A2-8-14-3.2-3.0          28.3
A2-6-8-2.6-2.0            21.0
A2-5-6-2.0-1.8             20.2
A2-4-3-1.4-1.4             19.3