Geneva Mechanism

Introduction:

The Geneva drive 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.

AIM:

The aim of the project is to understand the motion of the internal gear and perform a motion analysis of the internal geneva mechanism.

We have two wheels in the assembly:

1. Driving Wheel

2. Driven Wheel

We are going to perform two sets of calculations by giving different speed to the driving wheel and will plot a graph of 'Reaction Force' with 'Time'.

2D CAD Drawings of the internal Geneva Mechanism:

3D Assembly of the internal Geneva Mechanism:

Case 1: Driving Speed: 10 RPM @ 60 fps.

Contact Force plot with Time (Without precision):

Angular Displacement of the Driven Wheel (Without precision):

Case 2: Driving Speed: 20 RPM @ 120 fps.

Contact Force plot with Time (Without precision):

Angular Displacement of the Driven Wheel (Without precision):

Comparison of the contact force with and without Precision contact:

Case 1: Driving Speed: 10 RPM @ 60 fps.

Without Precision Contact: With Precision Contact:

Case 2: Driving Speed: 20 RPM @ 120 fps.

Without Precision Contact: With Precision Contact:

Angular velocity of the Driver Wheel:

Results:

1. Upon the comparison of the contact forces (With Precision or Without Precision) in both cases, we clearly understand that the magnitude of forces has increased to an extent.

2. The Driver's speed remains constant for the entire motion analysis.