The Gears subcategory within Power Transmission encompasses a range of mechanical devices used to transmit torque and change the speed or direction of motion in machinery. Gears operate by interlocking their teeth with those of another gear, which allows them to alter the torque and speed between a driving and a driven machine component. Gears are fundamental in a variety of mechanical systems, from small devices like watches to large industrial machinery. They are crucial for efficiently increasing or decreasing speed, distributing power among components, or changing the direction of rotation. Common types of gears include spur gears, helical gears, bevel gears, and worm gears, each designed for specific applications and load requirements. Gears are key to enhancing the functionality and performance of many types of machinery, providing precise motion control and power transmission capabilities.