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Whitworth Quick Return Mechanism
The Whitworth quick return mechanism converts rotary motion into reciprocating motion, featuring a slower forward stroke than the return stroke, hence its name. It comprises a driving crank and a driven slider crank with kinematic analysis covering position, velocity, and dynamic forces. This mechanism is historically used in machines like crank shapers and rotary engines.
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Whitworth Quick Return Mechanism
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- 2. INTRODUCTIONThe Whitworth quickreturn mechanism converts rotary motion into reciprocating motion, but unlike the crank and slider, the forward reciprocating motion is slower rate than the return stroke. This is why it is called quick return mechanism. This mechanism is made of a driving crank and of a driven slider crank. In the considered configuration, the fixed pivot of the driven crank is located on the outside of the circle on which the end of the driving crank moves. This leads to an alternated motion of the slider crank. The angular speed of the driven crank is variable. The duration of the motion for its part corresponding to the blue arc is shorter than the one related to the red arc. This is why this device is named quick return mechanism, which was used in crank shapers, with the slow part or the stroke being used for the working time of the tool and the quick part for the non-productive time.
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- 5. History cutting machine bySir Joseph Whitworth
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- 7. Power driven Sawmachine
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- 14. Kinematic Analysis ofthe Whitworth Quick Return Mechanism (FIG 1)
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- 22. Dynamic Analysis ofthe Whitworth Quick Return Mechanism
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- 24. Figure3 FBD oflink 2
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- 35. SIMULATION ON ADAMS(SLIDER)
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Editor's Notes
- #6 Whitworth quick return mechanism was developed by the British manufacturer Sir Joseph Whitworth around 1840.He was a machine tool builder and he sensed that speed of cutting tool on the shaping machines in his factory were not quick enough. So he adopted an inversion of the slider crank mechanism and fixed the crank. In the resultant mechanism backward stroke was faster than the forward stroke hence this mechanism speeded up the return of the cutting tool to the beginning of the cutting stroke thus saving time.