31-03-2017, 03:02 PM
A rapid return mechanism is an apparatus that converts circular motion into a reciprocating motion in presses and forming machines, which are used to form metal stocks on flat surfaces, Through mechanical engineering. The fast return mechanism is the basis behind the power of these machines. The mechanism consists of an arm attached to a rotating disk that moves at a controlled uniform speed. Unlike the crank, the arm of the mechanism operates at a different speed than the disc. By making the disk operate at a different speed than the joined arm, productivity increases because the amount of time required for a cut is reduced. The design of this mechanism specializes in vector calculus and physical aspects of kinematics (study of motion without the effects of forces) and dynamics (study of forces affecting motion).
![[Image: Crank-and-Slotted-Link-Mechanism.jpg?resize=730%2C690]](https://i1.wp.com/www.educationdiscussion.com/wp-content/uploads/2015/04/Crank-and-Slotted-Link-Mechanism.jpg?resize=730%2C690)
'KA' indicates the starting point of the forward cut stroke and 'KB' at the end of the cutting stroke. The rotation of the crank 'OP' clockwise through the angle P1RP2 refers to the forward cutting stroke. The rotation of the crank in the same direction through the angle P2LP1 refers to the return stroke. Since the angle P2LP1 is less than the angle P1RP2, the time taken for the return stroke is less than that of the forward stroke. Therefore, it is evident that the speed at which the ram travels during the return stroke is more.
