What component ensures both doors travel at the same speed in opposite directions in a center opening cable relating device?

The midpoint clamp is the correct answer because it serves a crucial role in regulating the movement of the doors in a center-opening elevator system. When the elevator doors are designed to open in the center, they typically move in opposite directions on the same vertical plane. The midpoint clamp functions to synchronize the speed of both doors, ensuring they open and close at the same rate and maintain a balanced operation. This is essential for safety and the smooth functionality of the elevator system, as it prevents one door from obstructing the movement of the other and ensures that doors close properly without gap or misalignment.

Other components, while important for overall elevator operation, do not have the same direct role in ensuring door synchronization. For example, the drive sheave is involved in moving the elevator car but does not control door speed. The control panel manages the operation and commands of the elevator system but does not directly influence the physical movement of the doors. Lastly, a limit switch is important for detecting the position of the doors, ensuring they are fully opened or closed, but again, it does not coordinate the speed of the doors during motion.