Which type of gear mechanism is characterized by two non-parallel shafts?

Bevel gears are specifically designed for applications where two shafts need to be connected at an angle, typically 90 degrees, although other angles are also possible. Their unique shape allows for the transfer of motion and power between non-parallel shafts, making them ideal for changing the direction of rotation. This characteristic is crucial in various machinery where space constraints or alignment issues necessitate the use of angled shafts, allowing them to be widely used in automotive applications, machine tools, and power transmission systems.

In contrast, spur gears are used primarily for parallel shafts and provide straightforward motion transfer along a single plane. Helical gears, while capable of handling greater loads and smoother operation than spur gears, are also designed for parallel shafts but have their teeth cut at an angle. Worm gears, on the other hand, are used primarily for non-intersecting shafts and high gear reduction, which differs from the mechanics of bevel gears. Therefore, the distinctive feature of bevel gears is their ability to connect non-parallel shafts, making them the correct answer in this context.