Degrees of freedom

Degrees of freedomDr.G.SivakumarSYLLABUS : UNIT -1Definitions-Degree of Freedom, Mobility-Kutzbach criterion-Grashoff's law-Kinematic Inversions of 4-bar chain, single and double slider crank chains-Mechanical Advantage-Transmission angle. Description of common Mechanisms: Single, double and offset slider mechanisms - Quick return mechanisms - Ratchets and escapements - Indexing Mechanisms.

Ratchets & escapements : indexing mechanismsRatchets and escapements are used in locks, jacks, clockwork and other applications requiring some form of intermittent motion.Paul & ratchet mechanisms This mechanism is used in producing intermittent rotary motion member Ais theratchet wheel, andBis an oscillating lever carrying thedriving pawl,C. Asupplementary pawlatDprevents backward motion of the wheel. When armBmoves counterclockwise, pawlCwill force the wheel through a fractional part of a revolution dependent upon the motion ofB. When the arm moves back (clockwise), pawlCwill slide over the points of the teeth while the wheel remains at rest because of fixed pawlD, and will be ready to push the wheel on its forward (counterclockwise) motion as before.

GENEVA MECHANISMTheGenevadrive or Maltese cross is a gear mechanismthat translates a continuous rotation into an intermittent rotary motion. The rotating drivewheelhas a pin that reaches into a slot of the drivenwheeladvancing it by one step.

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