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Geneva Mechanism Design Equations

Machine Design and Mechanics

Geneva Mechanism Design Equation and Calculator

The Geneva Mechanism or Maltese cross is a gear mechanism that translates a continuous rotation movement into intermittent rotary motion.

The rotating drive wheel is usually equipped with a pin that reaches into a slot located in the other wheel ( driven wheel ) that advances it by one step at a time. The main wheel also has an elevated circular blocking disc that "locks" the rotating driven wheel in position between steps.

Related:

Geneva Mechanism Animation

Geneva Mechanism External Design Equations

Kinematics of the External Geneva Drive. Assumed or given: a, n, d, and p.

a = crank radius of driving member
and
m = 1 / ( sin (180/n) )

n = number of slots in drive
d = roller diameter
p = constant velocity of driving crank, rpm
b = center distance = am

D = diameter of driven Geneva wheel

ω = constant angular velocity of driving crank = pπ/30 rad/sec
α = angular position of driving crank at any time (degrees)
β = angular displacement of driven member corresponding to crank angle α.

Reference:

Handbook of Machining and Metal Working Calculations, Ron A. Walsh 2001