One of the best mechanical prusiks for tree care!
The Petzl ZigZag Mechanical Prusik allows the user to move around efficiently in a tree using a classic prusik pulley system technique. The linked rings provide precision and fluidity when moving around. The pulley is mounted on sealed ball bearings to allow the slack to be taken up easily. The steel construction offers great durability.
1. Redesigned attachment holes to help keep the karabiners loaded correctly on the major axis.
a. Rope end attachment hole – The Zig Zag has a flexible elastomer ring that helps keep the karabiner in its optimal working position, thus reducing the risk of poor positioning (cantilever and/or reversal).
b. Harness attachment hole (swivel) – It has been enlarged to reduce the risk of poor karabiner positioning. This change also helps prevent karabiner sleeves from snagging.
Important: These two changes were tested and approved using OK (TRIACT-LOCK) and Am’D (TRIACT-LOCK/BALL-LOCK) karabiners. Other karabiner models of similar shape may be used, but their compatibility must absolutely be verified by the user. These two changes do not exempt the user from needing to be vigilant about the proper positioning of karabiners, whose strength is greatest when loaded on the major axis.
2. Increased strength of the rope end attachment hole. In normal use, the flexible positioning ring helps keep the karabiner from tilting. This tilting could be caused by an inappropriate movement or by rubbing against a branch, for example. This is why the rope end attachment hole has been reinforced to increase its strength for such an event. The following tests were performed to precisely measure the strength associated with different cases of poor positioning. These tests were performed using OK (TRIACT-LOCK) and Am’D (TRIACT-LOCK/BALL-LOCK) karabiner.
Test 1: rope end karabiner slightly askew:
Test 2: cantilevered rope end karabiner:
Test 3: cantilevered harness attachment karabiner:
The lowest value obtained in these tests for poor karabiner positioning was always greater than 12 kN.
3. Additional improvements:
a. Rope path exit – The Zig Zag side plates have been extended to better guide the rope in the sheave. They are also now flared to ensure smooth operation even if the rope rubs on the side plates.
b. Chain stop – The side plates have been modified to improve the chain stop contact surface and to increase the angle.
c. Riveting – The rivets have been modified to facilitate assembly during production. This change has no effect on product performance.