Five critical devices that can save equipment, materials--and lives
By Bernie Faloney
We read about it all too often--a person on a jobsite climbs behind the controls of crane to transfer a load. He "eyeballs" the load, and tries to save time by not setting outriggers, assuming the crane can do the job. In the midst of the move, the load shifts or proves to be too heavy, the crane begins to tip, and the entire rig falls over, causing damage to the jobsite, the crane and perhaps injury to the operator and others.
When a crane is pushed beyond its capacity, it is only a matter of time before damage occurs. Once equipment is forced to operate beyond its manufacturer's specifications, a crane can become unbalanced, rigging can break and people can get injured.
To help make crane owners and operators more aware of a crane's lifting limitations, manufacturers such as Fassi include safety equipment and alerts that make overextending a crane more difficult, or, at least, to keep a bad situation from becoming worse.
Before you buy or get behind the controls of an articulating crane, there are a few basic devices you should make sure are in place and up to date.
Lifting Moment Limiting Device
The scenario described in the introduction illustrates a crane collapse, which, according to the Bureau of Labor and Statistics, is the leading cause of crane-related damage, injury and death. Collapse often happens when a crane is pushed beyond its lifting limit at a given reach or if a crane's outriggers aren't properly placed.
A lifting moment limiting device can help prevent collapse by first alerting an operator to an overload, and, secondly, by stopping a crane from performing any further actions that might worsen the situation.
In a Fassi crane, pressure transducers on the lifting rams read the pressure brought about by the load inside the lifting ram cylinders. The transducer transfers the signal to sensors in an electronic card, which houses a preregistered, pre-set pressure limit. When the pressure reaches that limit, the card sends a power-down signal to the emergency solenoid in the crane's engine. The signal cuts off the pressure inside the distributor and, with the exception of rotation and retraction of the boom, the crane can no longer function.
Anti-2 Block (A2B) Device
Another significant cause of accidents and damage on a job site occurs when a load drops either from being released from the crane or when the wire rope breaks. A common reason for wear and tear on wire ropes, broken ropes, or loss of control of the load is when a two-block condition occurs. A two-block happens when the lower hook block is raised until it contacts any part of the boom tip hardware, which can cause the lower hook block to be drawn over the top sheave or cause the wire rope to break--either of which could cause the load to fall. A two-block situation can occur when a load is being winched up or when a boom is being extended.
An anti-two-blocking device (A2B) consists of a weighted ring around the hoist line; the ring is suspended on a chain from a limit switch that is attached to the boom tip. When the hook assembly touches the suspended weighted ring, the switch opens and an alarm in the cab warns the operator to stop hoisting.
Outrigger Monitoring System
Another cause of crane collapse is improperly placed--or unplaced--outriggers. A crane's outriggers provide stability and support for a load by displacing the weight of the crane and the load over a wider expanse of area. The outriggers can be adjusted to compensate for the position of the mounted crane or the angle of the load. Just as a load-limiting device suspends crane activity when the sensors read that the crane is overloaded, so an outrigger monitoring system automatically limits crane operation if lateral supports and outriggers aren't extended fully or at the proper angles. This system also monitors whether the surface beneath the outriggers is providing enough stability for the load. Depending on the model of crane, the supporting outriggers may compensate for failure of other outriggers.
Radio Remote Controls
Most modern articulating cranes are controlled by a wireless, radio remote control. But not all radio remotes are created equal. For the purposes of safety, a radio remote should keep an operator informed of all elements of the equipment, including the angle and position of the crane and the jib, the percentage load on the winch, the oil temperature, the level of battery charge, the angle of the outriggers and more. With all operational elements visible, a crane operator can monitor the crane's activity and have appropriate warning of any potentially hazardous situations.
Most cranes are uniquely identified with one radio remote, ensuring that no other remote controls can interfere with crane operation. Some radio remote operators have expressed concern over the proliferation of radio signals in the air and the potential for interrupted communication, but the US, like most countries, has protected bands exclusively for equipment operation.
In addition to monitoring a crane to prevent an accident or failure, safety devices can also keep track of equipment wear and service needs. This prevents gradual failure through a pre-programmed notification of developing problems and required service. A maintenance monitor can remind owners and operators when it is time to lubricate; check hoses, gaskets and fluids; or take a crane to a service center for more detailed maintenance. This not only keeps track of equipment wear to prevent failure, it can also save thousands of dollars in avoided downtime.
In addition to confirming key safety features such as the ones previously discussed, I would add that it is equally important, if not more so, to educate crane operators on warning signs, safety procedures, "pre-flight" checklists and best practices. Taking the time to assess a load, the equipment and the jobsite is a far better investment than having to look back at an accident site and determine how it could have been prevented.
About the author: Bernie Faloney is the CEO of Fascan International, the sole US distributor of Fassi Cranes. For more information call 800-632-7226, or visit www.fascan.com.