Internal Geneva Mechanism

AIM: CREATE THE 3D MODEL & ANALYSE FOR INTERNAL GENEVA MECHANISM USING SOLIDWORKS.

OBJECTIVE:

• Create 3D models for driver and driven wheels.
• Perform motion analysis by rotating the driver wheel at 10rpm.

Obtaining the following plots

• Contact force (between driving and the driven wheel) as a function of time.
• Angular Displacement of the driven wheel.
• Comparison of the contact forces with and without "Precise contact", & image for the precise contact selection

• The "Precise Contact" follows the two conditions

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

• plot of the driver wheel's angular velocity and discussion of the results

Export the results to Excel

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.

External Geneva mechanism: 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

figure: external Geneva drive in operation

Internal Geneva mechanism

In this type of mechanism, the Geneva cross and cam drive are connected internally in the closed box. The driver and driven wheel rotate in the same direction

Figure: assembly of internal Geneva mechanism

Uses and applications

One application of the Geneva drive is in film movie projectors and movie cameras, other applications of the Geneva drive include the pen change mechanism in plotters, automated sampling devices, banknote counting machines, and many forms of indexing equipment used in manufacturing (such as the tool changers in CNC machines; the turrets of turret lathes, screw machines, and turret drills; some kinds of indexing heads and rotary tables; and so on). The Iron Ring Clock uses a Geneva mechanism to provide intermittent motion to one of its rings.

1.3D Models Of The INTERNAL GENEVA DRIVER WHEEL

2. 3D MODELS OF THE INTERNAL GENEVA DRIVEN WHEEL

3. ASSEMBLY OF THE INTERNAL GENEVA MECHANISM

BODY OF CONTENT:

1. Study-1 (with 60 frames per second and 10 rpm motor speed)

Firstly we will set up the motor speed to 10 rpm and the contacts between the parts. (without precise contact)

→ Required Values Set Up Images

→RESULTS

Comparison of the contact forces with and without "Precise contact", & image for the precise contact selection

The "Precise Contact" follows 60 frames per second and 10 rpm motor speed.

2. Study-2 : (120 frames per second and 20 rpm motor speed)

Firstly we will set up the motor speed to 20 rpm and the contacts between the parts.

Comparison of the contact forces with and without "Precise contact", & image for the precise contact selection

The "Precise Contact" follows 120 frames per second and 20 rpm motor speed.

motion analysis video