Internal Geneva Mechanism
INTERNAL GENEVA MECHANISM ANALYSIS USING SOLIDWORKS MULTIBODY DYNAMICS
AIM
To create a part and assembly for the given drawing of the internal Geneva mechanism and analyze the multibody dynamics using Solidworks.
OBJECTIVE
- To create 3D models for driver and driven wheels.
- To perform motion analysis by rotating the driver wheel at 60 frames per second and 10 rpm motor speed.
- 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 perform motion analysis by rotating the driver wheel at 120 frames per second and 20 rpm motor speed.
- To obtain a plot for the Angular velocity of the driving wheel.
OVERVIEW
Geneva mechanism, one of the most commonly used devices for producing intermittent rotary motion, characterized by alternate periods of motion and rest with no reversal in direction.
Early motion-picture projectors used Geneva mechanisms to give the film a quick advance while the shutter was closed, followed by a dwell period with the shutter open.
EXTERNAL GENEVA
In this type, the Geneva cross is connected with cam drive externally which is the most popular and can withstand higher mechanical stresses.
INTERNAL GENEVA
In this type, the Geneva cross and cam drive are connected internally in the closed box. The driver and the driven wheel rotate in the same direction.
APPLICATION
- One application of the Geneva drive is in film movie projectors and movie cameras, where the film is pulled through an exposure gate with periodic starts and stops.
- Geneva wheels having the form of the driven wheel were also used in mechanical watches.
- Other applications of the Geneva drive include the pen change mechanism in plotters, automated sampling devices, banknote counting machines, and many forms of indexable equipment used in manufacturing.
3D MODELS
- DRIVEN WHEEL
2. DRIVER WHEEL
3. ASSEMBLY
BODY OF CONTENT
- Study-1(Plot for 10rpm 60Fps without precise contact)
(Plot for Angular Displacement at10rpm 60Fps)
(Plot for 10rpm 60Fps precise contact)
Image for precise contact selection
Comparing reaction force for with and without precise contact
2. Study-1(Plot for 20rpm 120Fps without precise contact)
Result
Thus the Internal Geneva mechanism is analyzed using Solidworks multibody dynamics and it is found that the reaction forces reach its peak when the cam of the driver enters the slot of the driven. It is also found that the no of readings within the given time is more for precise contact than without precise contact. In this way, the reaction force is observed closely. To reduce the reaction force either the driven component slot size can be increased or the cam of the driver can be reduced.
This is the link for motion analysis
Solidworks files
https://drive.google.com/drive/folders/17kggd6dL_Hb8-vHTnC7UTiX8uw_au0UK?usp=sharing