A pneumatic scrap removal device keeps material flowing for one agricultural OEM
December 2012 - Is it possible to yank a tablecloth out from under a setting of plates, wine glasses and silverware without everything crashing to the ground? Consulting an episode of Discovery Channel’s “MythBusters” or reading up on the laws of motion offer entertaining insight. However, the same physics behind the tablecloth trick also are the basis for a simple, effective scrap removal device being used by New Holland Agriculture.
The New Holland, Pa.-based company, a part of CNH America LLC, manufactures equipment such as combines, harvesters and hay balers and produces about 70 percent of its own components for the machines. Its 500,000-square-foot building is a massive operation in eastern Pennsylvania. The company punches various components on 100-ton to 250-ton mechanical punch presses, which leave behind scrap steel, according to Ernie Walker, plant maintenance supervisor at New Holland.
To continually move the punched parts and scrap material into separate bins, New Holland uses the Model 320 Transporter, made by Vibro Industries, Port Royal, Pa. The Transporter is a linear scrap removal device built around a pneumatic cylinder that, when fitted with a tray to catch scrap, pumps back and forth, shuttling the material down the tray, similar to a conveyor belt. Before installing the Transporter, New Holland’s operators would rake scrap away from the punch presses manually.
“What led us to Vibro was that we were looking for the best way to get the material both moved into the machine and out, as far as our punch presses, separating our scrap from our good parts,” says Walker.
New Holland feeds coiled steel sheet directly into its punch presses and processes the parts, which fall into one tray. Adjacent to the part tray is the scrap tray that empties into a scrap bin. Both parallel trays in this instance are powered by one Transporter—achieving twice the work in one operation.
“The trays are just long scrap steel runs that are bent and fastened to a bracket and attached,” Walker says. “It’s a home-built assembly. We have our in-house tool and die shop in the plant that can build the trays how we need them.”
Yank the cloth
At first look, the Transporters are simple devices. Ranging in size from a brick to a shoebox, they easily mount to a machine manifold or other fixture via two bolts. With a tray fastened on the top, all the Transporters need is air to get moving. That single variable eliminates headaches and costs associated with other conveyance systems. The Model 320 weighs 13 pounds and can support a 25-pound tray.
Slow acceleration in the forward stroke transports scrap material forward. On the rapid return stroke, material remains stationary as the tray pulls back underneath, the same way the plates remain as a tablecloth disappears beneath them.
New Holland can adjust the air pressure to accommodate material load weight. The Model 320 runs on a range of 35 psi to 80 psi. The easy air pressure adjustment reflects the simplicity of the design.
Lee Johnson, president of Vibro Industries, says a choke-like adjusting rod regulates the airflow.
“If you have heavy parts like slugs for a truck frame, you can use 50 psi,” Johnson explains. “But if you have the adjusting rod all the way in, it covers half the orifices. You have to back the rod off, which will let more air in the unit. If you’re running small parts, you don’t need high pressure because the weight is what you need the air for.”
New Holland now has about 20 Transporter units installed in one-, two- and three-tray configurations. Each unit is connected to an air hose running off a five-compressor central system. As a safety measure, the Model 320 automatically stops and restarts in case of an obstruction without hurting the unit or the operator.
“The air is piped over and plumped off of each machine, then we just plug them in,” Walker adds. “We’re running them full-time, as much as we’re punching, especially when we’re running automatic jobs. We adjust the Transporters based on the speed of our coils going through.”
No springs, no problem
What sets the Transporter apart is its reliance on air, and only air, to power it, says Johnson. Similar linear material handling systems use air-actuated pistons and incorporate a spring to generate oscillation. Springs can fatigue or break. The fact that the Model 320 only consumes 35 psi makes it remarkably efficient, as well.
“One of our sales representatives once demonstrated a Transporter with a bicycle pump. They use very little air,” Johnson says, noting the Transporter line is certified by two independent companies for its low air consumption.
Vibro offers three other Transporter models in addition to the 320, which is the second smallest in terms of capacity. Each is engineered as a rugged, reliable unit that can fit into tight spaces at the point of scrap ejection without necessarily being close to the tool. Vibro initially introduced the Transporter in Europe in 1984 as a solution to automating scrap removal for machine shops, then brought it to the U.S. market six years later. Johnson cold-called companies in Pennsylvania, leaving behind a Transporter to try.
“Two weeks later, one company said, ‘I’ll give you an open purchase order for two per month for a year.’ That’s how it started, door to door,” he adds.
The Model 320 and Model 450 are single-action transporters manufactured from steel, while the Model 250 and Model 850, the smallest and largest, respectively, are made from aluminum. Each model contains stainless steel liners for the cylinders. The whole Transporter line is capable of moving material from 12 to 40 linear feet per minute. In the course of a month, New Holland generates approximately 60 tons of scrap material including scrapped parts, with a majority of it carried by the Transporter, according to Walker.
Occasionally the piston seals can get gummed up, “but a lot is from the process of the oiling of the steel sheets as they’re coming through the punch,” Walker says. Besides regular maintenance by the machine operators, the Transporters require little upkeep.
Vibro provides a two-year warranty with each Transporter, Johnson says. After two years, customers can send theirs back in for new bearings, pistons and carriage rails. “Then, we warranty it again for another two years for a quarter the price of a new one,” he says.
Because the Transporters are uncomplicated devices, they easily adapt to an array of industries. Johnson says initially Vibro concentrated on the automotive and OEM industries, but it’s not uncommon for food industry customers to source Transporters. Island Princess, a macadamia nut processor in Hawaii, uses the Transporter to sort nuts from their shells.
“We never thought we’d be in the food industry,” says Johnson.
From a maintenance aspect, keeping the Transporter working properly is easy.
“We like to say our Transporters are built like a Ford Model T. It’s not like a Mercedes where you have to send it back to the factory for maintenance or rebuilding. Any good mechanic can change two O-rings,” Johnson says. “And you can have any color you want, as long as it’s black.” MM