Bevel Gears are used to change the direction of rotation between shafts that meet at an angle.

• A. Spur Gears
• B. Helical Gears
• C. Bevel Gears
• D. Rack and Pinion

Answer: (C)

Bevel gears are cut on a conical surface, which lets them mesh when the two shafts intersect at an angle. This conical tooth geometry lets power flow between axes that cross, changing the rotation direction from one shaft to the other, typically at 90 degrees but at other angles as well. Spur gears have straight teeth on a cylinder and are meant for parallel shafts; helical gears also assume parallel axes and smooth out noise but don’t accommodate intersecting shafts in the same way. Rack and pinion converts rotary motion to linear motion rather than changing the direction between angled shafts. So bevel gears are the appropriate choice for transmitting rotation between shafts that meet at an angle.