Whitworth Quick Return Mechanism: Definition, Working, Advantages and Applications
Explain Whitworth Quick Return Mechanism.pdf: A Guide to the Single Slider Crank Chain Inversion
Whitworth quick return mechanism is a type of mechanism that converts rotary motion into reciprocating motion, but with different speeds for the forward and return strokes. It is an inversion of a single slider crank chain, which consists of three turning pairs and one sliding pair. It is commonly used in shaper machines and slotting machines, where the forward stroke is slower for machining purposes and the return stroke is faster as there is no machining process to be done.
Explain Whitworth Quick Return Mechanism.pdf
In this article, we will explain Whitworth quick return mechanism.pdf in detail, covering its definition, history, parts and construction, working principle, advantages and applications. We will also provide some resources for further reading and learning.
Definition of Whitworth Quick Return Mechanism
Whitworth quick return mechanism is a mechanism that converts rotary motion into reciprocating motion, but with different speeds for the forward and return strokes. The forward stroke is slower as it is the power stroke, while the return stroke is quicker as it is the idle stroke. The name implies that the mechanism returns quickly to its original position after completing the forward stroke.
Whitworth quick return mechanism is an inversion of a single slider crank chain, which consists of three turning pairs and one sliding pair. A turning pair is a joint that allows relative rotation between two links, while a sliding pair is a joint that allows relative translation between two links. A single slider crank chain has one link fixed, one link rotating about the fixed link, one link sliding along a fixed path, and one link connecting the rotating and sliding links.
History of Whitworth Quick Return Mechanism
Whitworth quick return mechanism was invented by British manufacturer Joseph Whitworth in 1840. He patented his invention in 1841 and used it in his shaping machines. Whitworth was a pioneer in mechanical engineering and precision manufacturing. He developed many innovations in machine tools, firearms, screw threads, metrology, and education.
Parts and Construction of Whitworth Quick Return Mechanism
Whitworth quick return mechanism consists of four main parts: crank, slotted bar and slider, connecting rod, and ram.
Crank: The crank rotates with uniform angular velocity. It gets power from a pinion wheel or motor. It has a slider mounted at its end that slides along a slotted bar.
Slotted bar and slider: The slotted bar is a bar with a slot for guiding the slider. The slider is connected to the end of the crank. The slotted bar is pivoted at a fixed point. Its other end is connected to the connecting rod.
Connecting rod: The connecting rod converts the rotary motion of the end of the slotted bar into reciprocating motion. It has a ram attached at its end that reciprocates along a horizontal direction.
Ram: The ram reciprocates in the horizontal direction. It has a cutting tool mounted on it that performs the machining operation on the workpiece.
The construction of Whitworth quick return mechanism can be illustrated as follows:
As shown in the above figure, link AC is fixed. Crank AB rotates about point A with uniform angular velocity. The slider b is mounted at the end of crank AB and slides along the slotted bar BC. The slotted bar BC is pivoted at point C and rotates about point C. At the end of the slotted bar BC, connecting rod CD is attached that converts rotary motion to reciprocating motion. The ram DE is connected at the end of the connecting rod CD and reciprocates along with the cutting tool E.
Working Principle of Whitworth Quick Return Mechanism
Forward stroke: For forward stroke, the crank AB moves from B2 to B1 in a clockwise direction. At the same time, point X on connecting rod CD moves from B1 to B2 in a clockwise direction and the ram DE moves in forward direction from Y1 to Y2. The movement of forward stroke is shown in the figure with a green dotted line.
Return stroke: For return stroke, the crank AB moves from B1 to B2 in a clockwise direction. At the same time, point X on connecting rod CD moves from B2 to B1 in a clockwise direction and the ram DE moves in reverse direction from Y2 to Y1. The movement of return stroke is shown in the figure with a red dotted line.
For forward stroke, crank AB has to complete angle α. For return stroke, crank AB has to complete angle β. Since α > β, it takes more time for crank AB to complete forward stroke than return stroke. Therefore, forward stroke is slower than return stroke.
Advantages of Whitworth Quick Return Mechanism
Some of the advantages of Whitworth quick return mechanism are:
It reduces the idle time of the machine by making the return stroke faster than the forward stroke.
It increases the productivity and efficiency of the machine by reducing the total time required for one cycle.
It reduces the wear and tear of the machine parts by minimizing friction during return stroke.
It simplifies the design and construction of the machine by using simple parts and joints.
Applications of Whitworth Quick Return Mechanism
Some of the applications of Whitworth quick return mechanism are:
It is used in shaper machines for shaping flat surfaces on metal workpieces.
It is used in slotting machines for cutting slots or grooves on metal workpieces.
It is used in planer machines for planing large surfaces on metal workpieces.
Conclusion
In this article, we have explained Whitworth quick return mechanism.pdf in detail. We have covered its definition, history, parts and construction, working principle, advantages and applications. We have also provided some resources for further reading and learning.
We hope this article has helped you understand Whitworth quick return mechanism.pdf better. If you have any questions or suggestions, please feel free to leave them in the comments below.
Conclusion
In this article, we have explained Whitworth quick return mechanism.pdf in detail. We have covered its definition, history, parts and construction, working principle, advantages and applications. We have also provided some resources for further reading and learning.
We hope this article has helped you understand Whitworth quick return mechanism.pdf better. If you have any questions or suggestions, please feel free to leave them in the comments below. ca3e7ad8fd