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Cranes Communicate to Prevent Accidents

About four years ago, when his company was in the process of developing technology to solve the problem of tower crane collisions, Kendall Strysick came across a product that was tested and developed in Singapore. About a quarter of the way into his own R&D, he decided to switch gears and bring the technology back to the United States as sole distributor.

“When I discovered this system, we stopped all development for our system in order to bring it to the market that much quicker,” says Strysick, president of Persha International, located in Collegeville, Pa.

Now in its third generation, the TAC-3000 has been embraced by safety directors and safety managers across both North and South America. In its latest generation, this product sports updated components and upgraded software. Being adapted to tower cranes utilized on rails, it will be launched in 2008 with black box capability for event recording.

“We've seen an average around the world of up to one contact a day between tower cranes,” says Strysick. “When you have congested areas and multi-tower sites, the risk is just incredible.” But, utilizing this technology, he says, “Safety directors are finding themselves able to sleep at night now.”

Built from the Earth's foundation

Utilizing navigational technology similar to that of a cruise ship or aircraft, the system works off the Earth's magnetic flux, and is non-GPS, so crane positioning is given in real time, says Strysick. “It's most beneficial in congested areas,” he says.

The fully computerized anti-collision system is designed to detect and anticipate the risk of hook block, jib or counter jib collision when multiple tower cranes are operating on a construction site, according to product literature. Installation is a four- to eight-hour process and the system can be used on hammerhead and luffing cranes.

The crane operator controls the system unless safe parameters are breached. Once the TAC-3000 detects a risk of tower crane collision, it calculates the relative distance, in real time, between potential collision paths and sends a signal to the other cranes. Designed to give the operator information on collision direction as well as identification of the colliding tower crane, the system gives the operator both visual and audible warnings.

As the system alerts the operator, it automatically decelerates or stops the tower crane's movement in order to prevent the impending collision. “Slow,” “cut” and “brake” settings can be customized at intervals to prevent swing shock.

Can-do with CANbus

With CANbus technology for inter-module communication, the system also utilizes magnetic sensors, a 32-bit CPU, wireless and PC technology in order to communicate wirelessly between cranes. Components take a 128-bit data encryption incorporated into the software with a USB dongle and 32-bit CPU to build a high-security measure for wireless download.

In addition to its wireless features, the system eliminates the need for site-teaching of collision paths. The technician simply inputs necessary data into the PC and wireless uploads settings to the cranes from ground level. Data input can be performed off-site before the tower cranes are even up, and can be uploaded once the cranes are ready for operation.

The system's magnetic angle sensor is engineered to accurately report relative jib position under tough conditions. Its LCD display monitor, installed in the operator's cab, can autonomously detect any module failure as well as the operation status of the other tower cranes in its operating group.

Because some sites are more complex than others, the TAC-3000 can be preset with a 25-point boundary protection area within which the hook block cannot operate or fly over. The Zone Protection Safety System protects up to six prohibited zones, with eight points each, in which the hook block or jib are not allowed to operate. Function depends on the height of the protected zone, but the jib of the crane will also be prevented from colliding into the protected objects.

“We saw the need, heard the horror stories from crane operators and safety managers about all the contacts they've had,” said Strysick. “This technology is really needed in the U.S. and world market.” He says safety and risk drove development of the system. One week of downtime would cost a company three times what this system would cost, depending on the jobsite, says Strysick.

“When you can reduce the risk on a jobsite, anything and all things should be done and no cost spared because you're dealing with people's lives.”

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