Technical Innovations
Virtually safe cranes from Grove
 Several groups of Canadian researchers used a crane lab donated by Grove to develop a 3-D simulator that would increase the safety and decrease the cost of training crane operators. |
Training crane operators takes a lot of time, is relatively costly, is weather dependent, and, quite obviously, requires cranes. But a collaborative effort involving the Virtual Environment Technology Center at the Integrated Manufacturing Technology Institute (IMTI) of the National Research Council of Canada; the Operating Engineers Training Institute of Ontario (OETIO); the Ministry of Training, Colleges, and Universities; and Grove has resulted in the development of a 3-D crane simulator.
Grove donated the crane cab used in the project, which is now at the point where real-life situations are replicated in the actual working model. Gerry Hughes, Director of OETIO, has been a driving force behind the simulator development. He had first-hand knowledge of the benefits of simulator use as an effective training tool for air traffic controllers when he was Director of Training at the National Transport Canada Training Institute prior to joining OETIO. According to Hughes, most accidents are attributed to human error, not machine malfunction, and better operator training is as critical a factor in safe crane operation as it is in safe flying.
There are numerous benefits in using simulation in the training process as an adjunct to actual crane operation. Screening and selecting potential crane operators can be done in a safe, controlled 3-D environment that realistically replicates crane operation without any of the risks involved with putting someone in a crane without any experience. While actual crane operation is a comprehensive method of learning and incorporates visual, audio, and touch senses, it is expensive and potentially dangerous for a novice. The 3-D simulator replicates actual operation and allows the trainee to use his or her senses just as they would in an actual crane.
The simulator programs produce a consistent standard applied across the board to all trainees. Also, no limits are placed on the simulation, allowing hazardous situations to be simulated in a risk-free environment. This freedom allows the limits of approach to power lines to be explored as well as tipping limits. Actual visual playback of performance allows an immediate review of operations with corrective action able to be taken on the spot.
The Project Leader, Oliver Schoenborn of IMTI, worked closely with Hughes in turning the Grove cab into a virtual environment for crane operation. All of the parties involved brought together the technology, crane operating experience, and training experience to develop the 3-D simulator. Presently in Ontario, compulsory training for a mobile hydraulic crane operator requires 6000 h of on-the-job training and two six-week in-school periods conducted in the classroom and on the OETIO's fleet of cranes. This program has been credited as the major factor in reducing crane and rigging fatalities in Ontario by almost 80% since its inception. The use of simulators is hoped to supplement the actual "seat-time" in the program and give operators more confidence and skills to safely operate cranes on the job.
- Jean L. Broge
Miller's new air plasma cutter
 According to Miller Electric Mfg. Co., its new Spectrum 375 CutMate air plasma cutter offers 60% faster cutting performance, the ability to cut metal 25% thicker, and up to 400% longer tip life than the Spectrum 300 CutMate it replaces. |
Miller Electric Mfg. Co.'s engineers developed several technologies that improved the performance of its new Spectrum 375 CutMate air plasma cutter over the Spectrum 300 it replaces. "These (technologies) include a pilot arc controller, power factor correction, line voltage compensation, and diagnostic capabilities," said Steve Hidden, Product Manager, Miller Electric. The machine is designed to improve efficiency in the HVAC, automotive, maintenance, and construction industries.
The unit's pilot arc controller turns on for a few milliseconds to initiate or reignite the arc, then shuts off. This step allows the machine to direct all its power to the cutting arc, increasing power from 25 to 27 A. It also allows standoff cutting. With this technique, the operator manually holds or sues a device that keeps the torch tip 1.6 to 3.2 mm (1/16 to 1/8 in) off the metal surface. Standoff cutting improves the flow dynamics of the plasma jet, where drag cutting tends to disrupt the flow.
"This machine cuts 9.5-mm (3/8-in) steel at 250 mm/min (10 in/min) when drag cutting, and 400 mm/min (16 in/min) when standoff cutting," said Hidden. "Using a standoff also increases maximum cutting capacity by 3.2 mm (1/8 in)" Miller offers roller guide accessories to aid in holding a consistent standoff to maximize cutting.
The pilot arc controller also extends consumable life by up to 400% through minimizing double arcing and keeping the plasma jet in a focused column. A continuous pilot arc, such as the one on the previous model, acted like a magnet that pulled the jet toward the tip and caused some wear. The pilot arc controller automatically restarts the pilot arc without retriggering the torch when cutting across air spaces, which is helpful when cutting grates, chain link fence, or other expanded and perforated metals.
According to Miller, the air plasma cutter is less susceptible to nuisance trips because it incorporates power-factor correction. This technology allows the unit to draw 20% less current than the previous model (28 vs. 34 A). Nuisance trips occur when drops in voltage create an amperage spike. Long extension cords often create voltage drops. Its line-voltage compensation feature regulates the input power to a fixed value, even if primary power fluctuates by 15%. Most other units operate within a 10% window.
"Rather than being susceptible to the voltage drops that normally occur at the very end of the cut," said Hidden, "the Spectrum 375 provides a brief burst of peak-performance power to cleanly sever the last piece of metal, reducing or eliminating grinding."
Onboard diagnostics features include LED indicators that turn on if gas pressure and power are lost, if the cup is removed, and when excess consumable wear is detected. The LEDs will blink for 60 s following a momentary glitch, enabling troubleshooting to be simple and fast.
"More often than not, simple problems related to the air line, primary power supply, or worn consumables are not easily detected by the operator," said Hidden. "Because many of these problems are only momentary, such as air filter or hose congestion, machines of the past have been unable to capture them. Now, operators can quickly tell if the problem is temporary, as well as determine its source."
The new unit features an ICE-27C torch and safety trigger guard that prevents accidental misfire. The electrode, cup, and swirl ring are interchangeable with the previous ICE-25C torch. The new swirl ring only fits into the torch one way, unlike the old ring that could be accidentally inserted upside down and cause inconsistent airflow and torch meltdown.
- Jean L. Broge
