3.1. Considerations in Transmission Motion

GEAR TRAINS

Gear trains consist in at least two gears that meet and mesh with each other. These systems are used to transmit motion between two or more closely positioned parts.

Elements to consider when building gear trains

The two main types of teeth in gear trains. In gears with straight teeth, the teeth grooves are parallel to the rotational axis. In gears with helical teeth, the groves are not parallel to the axis. Gears with straight teeth are noisier that helical teeth, but more efficient.

CHAIN AND SPROCKET SYSTEM

Like gear trains, chain and sprocket systems consists on at least two gears. However the gears do not mesh. They are connected by a chain and they are referred to as sprockets. Since sprocket teeth do not meet directly but mesh with a chain, chain and sprocket systems are used to transmit motion between two ore more distant parts. The main elements to consider when building a chain and sprocket systems are the following ones:

• 1. The teeth on the system sprockets must be identical

  2. The chain links must mesh easily with the sprocket teeth

  3. The system requires frequent lubrication to avoid the rapid wear of the chain and the teeth

  4. The smaller the sprocket, the faster it turns

WORM AND WORM GEARS SYSTEM

They are formed by a single worm (screw) whose rotational motion is transmited to one or more worm gears. The worm is also called an endless screw because it can drive the gear screw indefinitely . The elements to consider when building a worm ans worm gear systems are: