What are cables? Steel cables, a.k.a. wire ropes for cables over 3/8″ diameter, are a flexible connection mechanism used on a variety of lifting equipment. They are an evolution from chain links which were notorious for catastrophic failure. Unlike chain, steel cables are made from many strands of wires twisted into specific patterns for improved strength and flexibility. Failure of a single strand in the cable is less critical as the other strands can take up the load.
In the automotive repair industry steel cables are most commonly seen on 2 post and 4 post style automotive lifts.
A typical 2 post lift, consists of a high pressure hydraulic cylinder assembled into each tower. When powered up, these cylinders support the weight of the vehicle while the cables are used to balance out any uneven lifting conditions. Even though they don’t directly support load, they are still performing an important role of keeping the vehicle level on the lift.
Two post lifts typically have small diameter sheaves due to space constraints in their design. Smaller sheaves mean tighter bending radius and higher bending stresses on the wires. So, inspect your wire ropes and sheaves frequently as detailed in your owner’s manual.
On 4 post lifts, the wire ropes are responsible for supporting the weight of the vehicle andthe lift. Hydraulic cylinders pull on the ropes, which in turn raise the load. As you can imagine, if a wire rope on your 4 post hoist fails, the load will free-fall “until and if” the mechanical locks stop it. The “if” in that statement depends on the condition of you locking system. Clean, inspect and replace damaged or broken parts of your locking system immediately. Never use a lift with a malfunctioning locking system.
You may think this will never happen to you, but many owners and operators take their cables for granted making cable failure more common than you think. So please inspect your cables frequently and take them out of service when they don’t meet the standards.