Manufacture of Geneva Gear

HARDWARE PROJECT(MEE218)

PROJECT TITLE:

FABRICATION OF GENEVA GEARGUIDE:PROF.SURESWhat is Geneva Mechanism?TheGeneva driveorMaltese crossis agearmechanism which translates a continuousrotatory motioninto 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. The drive wheel also has a raised circular blocking disc that locks the driven wheel in position between stepsApplicationsMechanical watchesMovie projectorsCNC machinesBanknote countingIndexing tables in assembly line

How it works?In most of the arrangements, the driven wheel has four slots and thus advances by one step of 90degreefor each rotation of the drive wheel. If the driven wheel hasnslots, it advances by 360/nper full rotation of the drive wheel.Working Model

IBM 1402-7 tooth geneva gearDimensions and Tolerances

Past ResearchEffect of manufacturing tolerances on indexing accuracy and synthesis of Geneva mechanism.It is observed that indexing accuracy is different for constraint and unconstraint design corresponding to the same values of tolerances.The indexing accuracy of Geneva mechanism is affected by the impact experienced during the entry of the pin in the slots. Other ReferencesDesign of Geneva mechanisms with curved slots for non-undercutting manufacturing.Jyh-John Lee, Bin-Heng Jan

Synthesis of conjugate Geneva mechanisms with curved slots.Giorgio Figliolini, Jorge Angeles

Effect of Tolerances and Clearances in the Geneva mechanism.Akihiro Takanashi

Objective of the projectOur aim is to study the effect of tolerances on indexing and other kinematic phenomenon.The present mechanism in watches involves a 4-way slot of the driven gear. We wish to modify the mechanism by changing it to a 6-way slot of driven gear and study the effect on undercutting and tolerances.For this purpose, we plan to create a wooden prototype and study the effects. THANK YOU!