Suggested Technique for Creating a Helical Spring Around a Non-Linear Trajectory



This technique will go through the steps for creating a helical shaped solid using a variable section sweep, a sketcher relation that makes use of the trajpar parameter and a swept protrusion. This technique does not use the actual #Helical Sweep feature.


  1. Sketch a curve that defines the trajectory (shape) of the spring. Then create another curve parallel to the original by selecting #Feature, #Copy, selecting on the original curve and using the #Translate option to create a copy that is parallel to the original curve.

    Figure 1



  2. Create a surface using a variable section sweep: Select #Feature, #Create, #Advanced, #Done, #Var Sec Sweep, #Done. Select the default options for the feature, select one curve for the Origin Trajectory and the other curve for the X-Vector trajectory. Then sketch the section below. Note: Actual dimensions may vary.

    Figure 2


    Before completing the section, write the following sketcher relation: sd# = trajpar*360*N, where sd# is the symbol of the angular dimension in the sketch and N is the number of coils.



  3. Next create a swept protrusion using the outside edge of the surface as your trajectory: Select #Feature, #Create, #Protrusion, #Sweep, #Solid and #Done. Use the default options for the feature and when selecting the trajectory, use #Tangent Chain and select the outside edge of the surface. Now sketch your desired section on the cross-hairs (centerlines) as seen below.

    Figure 3



  4. Finally, the surface and datum curves may be placed on a layer and blanked to show the resulting helical coil.

Figure 4



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Laatst bijgewerkt: 22 November 2002