Parallel Crank Coupling

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According to Neil Sclater on page 315 of Mechanisms and Mechanical Devices Sourcebook, parallel-crank couplings are used to drive overhead camshafts in engines. Each shaft has at least two cranks connected by links for constant velocity action and to avoid dead points. The links must have full symmetry. However, this can lead to collisions between connecting bars at specific angles. To prevent this, full asymmetry is needed so the bars can vault over each other. Additionally, dynamic balance methods should be considered during design. In Autodesk Inventor v.2017, you can drive the angular constraint in the model browser for this purpose.