Technology gives direction to innovation
Spur gear represents gear technology in the most fundamental form, i.e., contact of teeth (gear mesh), speed of rotation and change in direction. Spur gears are widely used in instruments and control systems.

The essential features of a gear mesh are:

• Center distance.
• The pitch circle diameters (or pitch diameters).
• Size of teeth (or module).
• Number of teeth.
• Pressure angle of the contacting involutes.

Constancy of angular velocities or proportionality of position transmission is a prerequisite for gears. High-speed and/or high-power gear trains also require transmission at constant angular velocities in order to avoid severe dynamic problems. "A common normal to the tooth profiles at their point of contact must, in all positions of the contacting teeth, pass through a fixed point on the line-of-centers called the pitch point. (Law of Gearing)" It ensures proper and maximum transfer of speed and direction.