What safety device is typically found between the driving unit and hydraulic pump drive shaft?

The presence of a pump drive coupling shear section between the driving unit and hydraulic pump drive shaft serves a critical safety purpose within hydraulic systems. This component is designed to prevent damage to the hydraulic pump and the driving unit in the event of an overload or a mechanical failure.

When excessive torque is applied due to a jam or a blockage, the shear section is designed to fail, breaking the connection between the driving unit and the pump. This failure effectively disconnects the driving force, preventing further damage to more expensive components and enhancing overall system safety. By protecting both the hydraulic pump and the driving unit from potential catastrophic failures, the shear section plays a vital role in maintaining the integrity of the hydraulic system.

In contrast, other options like a pressure gauge monitor system pressure but do not provide a safety function directly related to mechanical failure, an emergency stop switch is more for immediate shutdown rather than a preventive measure between components, and the fluid reservoir serves the function of storing hydraulic fluid, rather than acting as a safety device. Therefore, the pump drive coupling shear section is specifically designed to handle issues arising from mechanical overload, making it the correct choice for this question.