Internal Geneva Mechanism

AIM:-

To perform and stimulate the Multibody Dynamics using Solidworks for the Internal Geneva Mechanism.

OBJECTIVE:-

To create motion study for two conditions:

1. 60 frames per second and 10 rpm motor speed.
2. 120 frames per second and 20 rpm motor speed.

To create 3D models for driver and driven wheels.

To perform motion analysis by rotating the driver wheel at 10 rpm.

To obtain a plot for contact force between driving and driven wheel.

To obtain a plot for Angular displacement of the driven wheel.

To compare the contact forces with and without “Precise contact”.

To obtain a plot for Angular velocity of the driving wheel.

To export the results to a spreadsheet.

OVERVIEW:-

The Geneva drive or Maltese cross is a great mechanism that translates a continuous rotation into an intermittent rotary motion. The rotating drive wheel has a pin that reaches into a slot of the driven wheel advancing it by one step.

EXTERNAL GENEVA:-

In this type of mechanism, the Geneva cross is connected with cam drive externally which is the most popular and can withstand higher mechanical stresses. The driver grooves lock the driven wheel pin during dwell. During movement, the driver pin mates with the driven wheel slot.

INTERNAL GENEVA:-

An Internal Geneva drive is a variant on the design. The axis of the drive wheel of the internal drive can have a bearing only on one side. The angle by which the drive wheel has to rotate to effect one step rotation of the driven wheel is always smaller than 180° in an external Geneva drive and always greater than 180° in an internal one, where the switch time is therefore greater than the time the driven wheel stands still.

APPLICATION:-

• Stepper
• Mechanical Watches
• Plotters
• CNC Machine
• Iron Ring Clock

3D MODEL:-

DRIVEN WHEEL:-

DRIVER WHEEL:-

ASSEMBLY:-

Internal Geneva Mechanism Animation

BODY OF CONTENT:-

PLOT:

For 10 rpm and 60 frames per second - without Precise Contact:

Angular Displacement of Driven Wheel:

For 10 rpm and 60 frames per second - with Precise Contact:

Comparing the contact forces with and without "Precise contact":

Image for Precise Contact selection:

Angular Velocity for Driving Wheel – 20 rpm and 120 frames:

RESULT:

Thus the Internal Geneva Mechanism is been stimulated and performed using MULTIBODY DYNAMICS in solidworks. Here the reaction force is seen when the driver CAM enters the Slot of driven wheel. Also the number of values is more precise for the Contact force. Thus the Motion Study helps us to simulate the real time performance of the Internal Geneva Mechanism.

Link for Part and Assembly Files: Internal Geneva PART and ASSEMBLY FILE