On the quick–return motion capability of drag–link driven crank–slider mechanisms
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Abdullah Al-Dwairi [1] ; Duaa Al-Quran [1]
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[1] Jordan University of Science and Technology
Jordan University of Science and Technology
Jordania
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- Localización: Mechanics based design of structures and machines, ISSN 1539-7734, Vol. 53, Nº. 6, 2025, págs. 4746-4760
- Idioma: inglés
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Resumen
Quick–return motion is used in machines where a tool needs to move slowly in one direction and return rapidly for efficiency. Typical applications include shaper machines, powered saws, mechanical presses, and others. It is characterized by a time ratio (TR), which compares the duration of the slower stroke to that of the faster stroke. While a higher TR indicates greater productivity, it usually corresponds with a lower motion transmission quality. Therefore, when designing a mechanism, it is essential to identify the feasible TR ranges the linkage can achieve while maintaining acceptable transmission quality. Another constraint that often limits the attainable TR is the space occupied by the mechanism. This paper explores the feasible TR ranges of the mechanism using transmission quality and space occupation as design requirements. A non-dimensional model is developed and an inverse analysis is performed to find the time ratio function. We explore the design space by varying the pressure angles in the mechanism from 0 to 90 degrees. For each pressure angle, the mechanism proportions are calculated while independently varying the slider’s offset and crank–slider’s rigid connection angle to the drag link. Sample computations are presented in charts showing the TR adjustability ranges. A design example demonstrates how the charts can help select a mechanism for a desired stroke and TR. The methodology is applied to a deep-drawing press redesign case study, resulting in a smaller mechanism. The case study demonstrates how altering the connection angle impacts the overall output velocity profile, not just the time ratio
