Traveling block

{
  "id": "MLC-T-OAG-003909",
  "term": "Traveling block",
  "field": "Oil and gas",
  "definition": "A large, multi-sheave pulley system that moves up and down in the derrick, supporting the drill string and casing during drilling and tripping operations. It is reeved with the drilling line and works in conjunction with the crown block to provide the mechanical advantage needed to lift heavy loads. The traveling block is connected to the hook, which in turn supports the swivel or top drive.",
  "subject": "Drilling",
  "url": "https://mlchart.com/terminology/oil-and-gas/traveling-block/"
}