What function does the holding valve on a vertical outrigger jack perform?

The holding valve on a vertical outrigger jack is essential for maintaining safety and stability during crane operation. Its primary function is to hold pressure in the vertical ram of the jack if there is a hydraulic connection failure. This is crucial because, in the event of a hydraulic system malfunction, the holding valve prevents the jack from retracting unexpectedly, which could lead to a loss of support and potentially dangerous situations.

By ensuring that the pressure remains in the ram, the holding valve keeps the outrigger extended and stable until the operator can safely address the hydraulic issue. This function highlights the importance of safety mechanisms in crane operations, contributing to overall equipment reliability and operator safety.