Geometric Design of Closely Intermeshing Profiles

The following provides an outline of a geometrical design that enables self-cleaning profiles to be produced using elementary geometry. As a first step we determine the center M of the profile and draw the symmetry lines 1 and 2. 

If Z= 1 (single-flighted profile), the lines of symmetry 1 and 2 merge at the center of the profile. These two lines are the profile s lines of symmetry. The profile diameter reaches its largest point at line 1 and its smallest point at line 2. 

First we draw two circles with center M circle 3 with external diameter DE and circle 4 with the interna] diameter DI of the fully wiped contour. 

Between the lines of symmetry 1 and 2, we draw the angle-bisecting line 5 on the side facing away from the profile to be drawn. Following this line 5 by half the centerline distance, we obtain point R 

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