Fly system By trimming the lift lines, loads are more evenly distributed to them. Turnbuckles are moused (secured against free rotation) to prevent the jaws from slowly unscrewing over time due to vibrations incurred during normal use. Counterweight lift lines typically connect to the tops of arbors with shackles. A block is a pulley used to support and direct lift and operating lines. A block consists of a grooved wheel, known as a sheave (pronounced "shiv"), steel side plates, spacers, shaft, flange bearings, mounting angles and clips, etc. Blocks are sized based on anticipated live loads, operating speeds, line type and other
Lifting bag a hazardous operation with high risk of entanglement in an uncontrolled lift or sinking. If a single bag is insufficient, multiple bags may be used, and should be distributed to suit the load. There are also lifting bags used on land as short lift jacks for lifting cars or heavy loads or lifting bags which are used in machines as a type of pneumatic actuator which provides load over a large area. These lifting bags of the AS/CR type are for example used in the brake mechanism of rollercoasters. The volume of the bag determines its lifting capacity: each litre