Internal Geneva Mechanism
THE INTERNAL GENEVA MECHANISM
AIM:
To design the 3D model of internal geneva mechanism to obtain various plots and results.
OBJECTIVE:
- To Create 3D models for driver and driven wheels
- To Perform motion analysis by rotating the driver wheel at 10rpm.
- To Obtain the following plots
- Contact force (between driving and the driven wheel) as a function of time.
- Angular Displacement of the driven wheel.
- To Compare the contact forces with and without "Precise contact"
- To Show image for precise contact selection
- To export the results to Excel and make the plots over there.
- To make a plot of the driver wheel's angular velocity by changing 20 rpm.
OVERVIEW:
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 drive wheel also has an elevated circular blocking disc that "locks" the rotating driven wheel in position between steps.
An internal Geneva drive is a variant of 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 time switch is, therefore, greater than the time the driven wheel stands still.
APPLICATION AND USES:
- One application of the Geneva drive is in film movie projectors and movie cameras
- Geneva wheels having the form of the driven wheel were also used in mechanical watches
- A Geneva drive was used to change filters in the Dawn mission framing camera used to image the asteroid 4 Vesta in 2011.
- 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 MODEL:
DRIVING WHEEL:
DRIVEN WHEEL:
ASSEMBLY:
BODY OF THE CONTENT:
- For 10 rpm and 60 frames per second :
Without precise- contact force
The angular displacement of the driven wheel
For 10 rpm and 60 fps-with precise contact
Comparing the contact force -with and without precise contact
Image for precise contact selection:
For 20 rpm and 120 fps –angular velocity
RESULT:
Thus the 3D model of internal geneva mechanism has been designed and the plots for with &without precise contact forces and angular displacement(10 rpm @ 60 fps) & angular velocity ( 20 rpm @120 fps) has been plotted and compared.it is found that reaction force reaches its maximum value while entering the slots of the driven wheel.
https://drive.google.com/drive/folders/100Azmbj5P_-lX4a_wqgq_bGLFLgD73mV?usp=sharing