Yale Lifting Solutions was recently approached by a long-time client in the South African gold mining industry to provide a 200-ton capacity horizontal test rig used to proof load test humble hooks. Humble hooks are safety devices used to connect winder ropes to the main personnel cages and ore conveyances on hoists in vertical mine shafts.
How does the test rig work?
A humble hook is installed in the test rig and the operator sets the testing parameters. The test rig then automatically carries out the test and, upon completion, produces a test certificate containing relevant testing information that can be printed out or saved electronically. Typically, the rig tests each humble hook to 65 tons, but has a maximum testing capacity of 200 tons if needed. Each rig weighs more than 5,500 kg. (12,000 lbs.).
Also, because safety is a critical part of the way Columbus McKinnon does business, each test rig is fitted with a safety cage to prevent possible injury should something fail during the testing process. By use of strategically positioned limit switches working in conjunction with the control program, the test rig will only operate if the cage is closed. Once this test is complete, the humble hooks undergo an ultrasonic test before they are put into storage awaiting installation on the hoist.
In South Africa, it is a legal requirement that a short length of the front end of each winder rope on a mine hoist is cut off on a regular basis. Then, this wire rope sample is submitted to a testing laboratory for destructive testing and inspection, to monitor the residual strength of the rope. It is normal practice to replace the humble hook at the same time that the front end is cut. The humble hook in service is removed and the tested humble hook is installed in its place. To date, this is one of the largest manufacturing projects Yale Lifting Solutions has carried out in its newly formed manufacturing department.