Calculating the load of basket hitches and bridles
When you’re calculating the load of basket hitches and bridles, remember that as the horizontal angle of a sling decreases, the resultant load on each leg increases. The horizontal angle of bridles with three or more legs is measured the same way as horizontal sling angles of two-legged hitches. If a bridle is designed with different leg lengths, it may result in different angles. The load on each leg must be calculated based on the position of the slings and the location of the lift’s center of gravity.
Adjusting the rated capacity of choker hitch 120 degrees due to the body of the sling being used in the choke, there is reduction in rated capacity. This is reflected in the choker rated capacity tables. Another reduction that must be considered is due to the angle of the choke (not the angle of the leg of the sling).
If the load is hanging free, the normal choke angle is approximately 135 degrees. When lifting and turning a load using a choker hitch, it is not uncommon to have a sever bend at the choke. When a choker hitch is used at an angle of less than 120 degrees, you must reduce the hitch’s rated capacity as shown in the chart at right. You always must adjust the rated capacity of the wire rope sling whenever you use a choker hitch to shift, turn or control a load, or when the pull is against the choke in a multi-leg lift.
As always, if more than one sling is used and the legs are not vertical, a further reduction in rated capacity must be made for the sling angle.
Choker hitches at angles greater than 135 degrees are not recommended since they are unstable. Extreme care should be taken to determine the angle of choke as accurately as possible.