WHITWORTH QUICK RETURN MECHANISM

IT IS SIMPLE WITH AN UNDERSTANDING DIAGRAM AND HAS THE BASIC APPLICATIONS.

1. WELCOME

2. PRESENTATION ON WHITWORTH QUICK RETURN MECHANISM : PRESENTED BY , GOWTHAM.S - 15BME110 KINEMATICS OF MACHINERY

3. In slotter, the rotary motion of the electric motor will be converted into reciprocating motion of the ram. More over, the return stroke will be faster than the cutting stroke. QUICK RETURN MECHANISM :

4. The whitworth quick return mechanism generally used in slotter. An electric motor drives a pinion at constant speed. The pinion drives a bull gear at uniform speed. The bull gear has a crank pin (C) fitted with a sliding block. A crank plate is pivoted eccentrically on the bull gear at the point ‘o’ by a pin. WHITWORTH QUICK RETURN MECHANISM :

5. The crank plate has a slot along its length. The crank pin with sliding block slides along the slot of the crank plate. The other end of the crank plate is connected to a connecting rod through a pin ‘p’. The ram is fitted to this connecting rod. It is unlike the crank and slider mechanism, the forward reciprocating motion is slower rate than the return stroke . WHITWORTH QUICK RETURN MECHANISM :

6. When the bull gear rotates, the crank pin rotates about its centre. At the same time, the sliding block slides along the slot of the crank plate. This makes the crank plate to rotate about the point ‘o’. Thus the rotary motion of the crank plate is converted into the reciprocating motion of ram through the connecting rod. WORKING :

7. In the fig, C 1 & C 2 r epresent the two extreme positions of crank pin with sliding block. During the cutting stroke, the crank pin rotates from C 1 to C 2 in anti-clockwise direction through an angle θ 1 During the return stroke, the crank pin rotates from c 2 to c 1 in anti-clockwise direction through an angle θ 2 . The speed of the bull gear & the length of stroke during both the strokes are same. Referring the fig, angle (return stroke) is less than angle (cutting stroke). So the time taken for return stroke is less. Hence the ram moves faster during return stroke. WHITWORTH QUICK RETURN MOTION :

8. Quick return mechanisms are found throughout the engineering industry in different machines : Shaper Screw press Power-driven saw Mechanical actuator revolver mechanisms Water pumping system APPLICATION OF WHITWORTH QUICK RETURN MECHANISM :

9. Shaping machine

10. Water pumping system

11. Power driven saw machine

12. ROTARY ENGINE :

13. THANK YOU