Ladder Climbing Assist Device (Angel Lift)
A device consisting of a length of wire rope reeved over a sheave, with one end attached to a counterweight and the other end attached to a belt that passes under a person’s buttocks. As a person ascends or descends the mast ladder, the device acts as an assist by lightening the person’s weight.
Source: Petroleum Safety Orders–Drilling and Production, Definitions, California Code of Regulations, 8 CCR § 6505, December 2012. Regulations