ABSTRACT
Geneva mechanisms are characterized by a roller entering a slot and indexing the Geneva wheel, which, when the roller exits the slot, is locked in its position until the roller starts entering the next slot. Geneva mechanisms belong to a group of mechanisms having intermittent motion, that is, when the driving member rotates continuously the output member has a prolonged dwell. In a Geneva mechanism, it is very important that the roller enters the slot tangentially because otherwise shocks are generated and this might lead to a destruction of the entire mechanism at high speed and/or high loads. Star wheels are a combination of gears and modified Geneva mechanisms. The gears may be made with pin gearing or with teeth as in ordinary gears. With star wheels it is important to have an angular acceleration that is continuous, at least for relatively high speeds.
