Extension Springs - Modified Design Dialog Box (AutoCAD Mechanical Toolset)

Material

Specifies required material in accordance with the selected standard

Wire diameter d

Specifies wire diameters in accordance with the selected standard.

Outer Diameter Da

Enter a value for either the Outer Diameter Da, or index ratio Dm/d, where Dm is mean coil diameter, d is wire diameter of the spring.

Length L0

Specifies the unloaded length of the spring. The recommended value of unloaded length is displayed beside of edit box. If you want to change this value, switch on the check box and enter your value into the edit box. If the spring is specified by 2 forces and 2 lengths there is only one possible length L0, which is automatically calculated and edit box is disabled. Values L0 and F0 are dependent, that is why if you change the value of L0, the value of F0 is recalculated.

Preload Force F0

Specifies the preload of the spring. Preload can be defined only if check box “Overlapping Coils” is switched on. The recommended value of preload is displayed beside of edit box. If you want to change this value, switch on the check box beside of text “F0” and enter your value into the edit box. If the spring is specified by 2 forces and 2 lengths there is only one possible value of F0, which is automatically calculated and edit box is disabled. Values L0 and F0 are dependent, that is why if you change the value of F0, the value of L0 is recalculated.

Overlapping Coils

If this check box is activated, it means that the extension spring is preloaded with force F0 on distance L0.

Helix Direction

Select one of two spring helix directions: Right, or Left.

End Coils

Enter a required number of end coils together for both spring ends.

Left, Right tabs

After clicking on these tabs, you are able to set left and right spring end types. After press of spring end image button, you can select the required spring end in compliance with DIN 2097. Select one of them, and click OK. Now you can enter dimensions of end in the edit boxes Lh1, m1 or Lh2, m2. These input values are automatically restricted by type of selected hook and outer diameter of spring.

Results: Loads tab

 

Spring dimensions:

d-wire diameter x Da-outer diameter x L0-unloaded length. Depending on the selected standard, instead of outer diameter Da mean diameter Dm can be displayed.

 

Force:

F1- load in state 1, F2- load in state 2, Fn- maximum allowed load.

 

Deflection

s1- deflection in state 1, s2- deflection in state 2, sn- maximum allowed deflection.

 

Length:

Lengths of spring caused by corresponding forces (L1, L2, Ln). Number of displayed forces depends on selected specification.

Results: Stresses tab

 

Stress:

Stress in spring calculated according to the forces.

 

Allowed:

Allowed stress in spring

 

Safety:

Safeties calculated as a ratio between stress and allowed stress in the spring