Geneva Mechanism for a Rotary Indexing Table
A rotary worktable is driven by a Geneva mechanism with six slots, as in Figure 16.7. The driver rotates at 30 rev/min. Determine the cycle time, available processing time, and the lost time each cycle to index the table.

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Accepted Answer

With a driver speed of 30 rev/min, the total cycle time is given by Equation (16.2):

[latex]T_{c} = \frac{1}{N}[/latex]

[latex]T_{c} = (30)^{-1} = 0.0333 min = 2.0 sec[/latex]

The angle of rotation of the worktable during indexing for a six-slotted Geneva is given by Equation (16.1):

[latex]θ= \frac{360}{n_{s}}[/latex]

[latex]θ= \frac{360}{6}= 60º[/latex]

Equations (16.3) and (16.4) give the available service time and indexing time, respectively, as

[latex]T_{s} = \frac{(180+θ)}{360N}[/latex]

[latex]T_{s} = \frac{(180+60)}{360(30)}= 0.0222 min = 1.333 sec[/latex]

[latex]T_{r} = \frac{(180-θ)}{360N}[/latex]

[latex]T_{r} = \frac{(180-60)}{360(30)}= 0.0111 min = 0.667 sec[/latex]

Question 16.1: Geneva Mechanism for a Rotary Indexing Table A rotary workta...

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