When machinery binds or jams, which protective device is typically engaged?

• A. Overload clutch
• B. Relief valve
• C. Check valve
• D. Safety interlock

Answer: (A)

When a machine binds or jams, protection should stop the drive before heavy damage occurs. An overload clutch is designed for this scenario: it allows the drive to continue normally up to a preset torque, and if the load becomes too high because of a jam, the clutch slips or disengages. This prevents damage to gears, shafts, and the motor by limiting transmitted torque and stopping the drive. The relief valve is about releasing excess hydraulic or pneumatic pressure, not preventing a jam in a mechanical drivetrain. A check valve controls flow direction, not drive protection in a jam. A safety interlock prevents operation under unsafe conditions but doesn’t automatically disengage the drive when a jam happens. So the overload clutch is the protective device that engages to protect the machinery during a jam.