The company was using a basic valve combination when it started making drilling attachments. Sometimes, when the user touched the handle on the attachments that employed this set-up, all of the flow went to the drill at one time and caused it to move too fast, making it unsafe for the operator.

But that wasn’t the only issue that the old valves presented.
“With the old valve sections we were using, no matter what you did when you pushed that handle down, that function was draining 20 gallons per minute,” according to Sue Frank, TEI president. “Normally, you only have 40 gallons per minute for any machine, so your first two functions are essentially eating up everything that machine can put out. As a result, that third function might not operate quite as well.”

The valves TEI was using - that were at the core of the problem - were of the non-proportional variety. Consequently, when the company began employing 360° positioning capabilities on the attachments, it needed to find a proportional valve in order to control the flow of oil directed to the positioner. This would allow the operator to ease the attachment into position instead of slamming it, which is the way the non-proportional valves function.

TEI discovered Hawe Hydraulik, a Munich, Germany-based company could supply the ideal proportional valves for all of its applications. The company began purchasing Hawe valves from the company’s Charlotte, NC, facility in March 2004. The company uses a wide range of Hawe components, from the Size 2 to the Size 5 PSL valves, and purchases between 75 and 100 valves per year.

Most important was the fact that the Hawe valves would provide the stability that TEI’s drilling attachments - as well as its limited access drills - required. Concerns about operator safety would become a thing of the past.

“When we started out, we were making solely static mounts,” said Frank. “There were no positioning systems, so instability wasn’t a problem. When we incorporated positioning capability, we started with a modest 20 degrees side-to-side, which presented no safety issues to speak of.

“Still, sometimes a customer would fit a drill on a skid-steer at 20 degrees on the top of the feed mast. With all of the weight distributed at the top like that, the machine was actually prone to lifting to one side. No machine has ever tipped over, but the possibility was always there.

“The Hawe valves have solved that problem. With a more controlled flow of oil to the positioner, the attachment doesn’t ‘jerk’ the way it used to, making it far safer for the operator.”

Since the company is installing its drilling attachments on another vendor’s equipment, there is a limited amount of hydraulic flow at TEI’s disposal. This makes it essential that the available flow is used as efficiently as possible.

The size and shape of the Hawe valves are also crucial factors in the successful function of the drill attachment. In fact, ergonomic and contemporary machine design depends on compact hydraulics. Hawe valves offer space savings of between 20 and 40% in comparison to standard products.

Because units can be easily be stacked in different sizes, the valves can be kept compact. Rather than having eight large valve sections, two Size 5 valve sections and six Size 2 sections for positioning functions can be specified. Because valve sizes smaller, the various combinations ultimately mean less oil is consumed.

Hawe components are also capable of abating leakage because of their internal steel construction. So in the unlikely event that a drilling attachment is not properly manufactured, the Hawe valve can compensate minor engineering glitches.

The technical side of Hawe’s operation is excellent, said Frank. “We can send a schematic of what we have been doing as far as our valving, and tell the Hawe engineers what we’d like to accomplish,” she said.

This article was contributed by Hawe North America, Inc.
www.hawehydraulics.com