Fast Fours Mechanical Advantage System
The Fast Fours is a simple variation on a standard set-of-fours. The difference is that the far end of the rope is not terminated on the becket of a pulley. Instead it is run through another progress capture pulley. This means that an operator can either pull on both ends simultaneously to yield a fast take up 2:1 or a single strand for a 4:1.
There is another unique advantage of this system for fallen worker and confined space recovery. If capable, the fallen worker can pull on one end of the system while the rescuer pulls on the other which speeds the recovery, halves the individual work, and involves the victim in the task.
Products Used in this demonstration
The new Advance Tech HX is ideal for all rescue applications where a small mechanical advantage system is being used.The SMC Advance Tech HX Pulley is a double pulley with an integrated cam that provides immediate progress capture without the need of prussik loops.
The Petzl MICROTRAXION is a high-efficiency pulley with a cam device built in. The cams teeth ensure good traction on the rope even under less than ideal conditions, such as a frozen or muddy rope. The MICROTRAXION can be used in personal haul systems for immediate progress capture, for complex split-pull mechanical advantages and for self belay during climbs. The cam may also be locked off allow the MICROTRAXION to be used as a standard micro pulley.
Peace on your days…