... ), tower type, such as masts and packaged-type. · A thigh-derrick with rectangular or triangular cross-section, such as type, capacity ... and local stability. The use of inter-connecting pin. Derrick low installation, use Renzijia rely on the power winch from ... patch truss structure, the use of the inter-pin connection. Derrick low installation, use Renzijia rely on the power winch from ...