Shaft couplings, collars, and universal joints are parts that connect equipment to transmit power and help protect against shock, vibration, misalignment, backlash, and overload. Jaw couplings, sleeve couplings, and tire couplings do not require lubrication and are commonly used on electric motor applications, such as gearboxes, conveyors, and medical equipment. Motion control couplings provide good rigidity in moderate- to high-torque applications like servomotors, robots, and machine tools. Oldham couplings maintain constant velocity with low bearing loads and are ideal for applications with high parallel misalignment. Rigid couplings allow minimal backlash between shafts of the same dimension and are suitable for continuous-motion applications. Shaft collars, adapters, and keyed shafts hold bearings, sprockets, and gears to shafts and other components and can act as mechanical stops. Universal joints transmit torque between rotating shafts that are at an angle to each other.