What prevents the mast from being lowered or raised when the mast is extended?

• A. Lock pin
• B. Pressure (anti jog) switch
• C. Hydraulic lock
• D. Interlock relay

Answer: (B)

When the mast is extended, a safety feature in the hydraulic control circuit called the anti-jog pressure switch comes into play. This switch monitors the hydraulic pressure in the lift system and, once it detects the mast in the extended position, it disables the directional controls that would command raising or lowering. In effect, it prevents any movement of the mast while it’s extended, guarding against unintended jogs, overshoot, or instability that could occur from hydraulic pressure changes or control noise. The other options are mechanical or electrical safety devices, but they don’t automatically lock movement based on the hydraulic state in the same way the anti-jog pressure switch does.