Which component is specifically necessary for mounting a governor in elevator systems?

The correct answer highlights the importance of a lockwasher in securing components within an elevator governor system. Specifically, a lockwasher ensures that the screws or bolts used for mounting the governor remain tight and do not loosen over time due to vibrations or operational forces. This is critical in maintaining the safety and reliability of the elevator system since the governor is responsible for regulating speed and activating safety mechanisms during operation.

The lockwasher's function is to prevent the fasteners from backing out, which could lead to misalignment or failure of the governor. Such a failure could impair the elevator's performance and safety features, potentially endangering passengers.

In contrast, while other components like a sealing ring, pinion gear, and sprocket might play roles in various mechanical functions within an elevator system, they do not specifically address the need for secure mounting of the governor itself. Thus, their presence does not replace the necessity for a lockwasher in this context.