What switch type is not commonly used on hydraulic elevators?

The broken tape switch is not commonly used on hydraulic elevators primarily because hydraulic elevators rely less on physical barriers or detachment for operation compared to other systems. A broken tape switch functions by detecting when a tape or wire is pulled or broken, which is more common in systems that require strict positioning or have safety protocols based on the integrity of a tape that could be subject to wear and tear.

In contrast, proximity sensors, limit switches, and foot switches are widely used in hydraulic elevator systems. Proximity sensors can detect the position of the elevator car without physical contact. Limit switches are crucial for defining the upper and lower stops of the elevator to prevent overtravel, ensuring safe operation. Foot switches can be used for specific control actions, allowing for hands-free operation which can be beneficial in certain applications of hydraulic elevators.

Because of this functionality and operational reliability, the broken tape switch does not align with the typical requirements and safety measures employed in hydraulic elevator systems.