From the Field: Operator Presence System Sometimes Tricky on Older Walk-Behind Trenchers

Editor’s Note: Our readers recently told us they want more “real-world” product information; testimonials from peers about issues that have come up with equipment and how they were dealt with. The following is the result of our effort to bring more of this sort of product coverage to our audience. Please let us know what you think, and if you’ve had issues with a type of equipment and are willing to share your experience. You can do so by emailing Jenny Lescohier at jenny.lescohier@cygnus.com

Here’s the problem

Brent Younker, president at Total Rental in Gesham, OR says he’s had trouble with the operator presence system on some of the older models of walk-behind trenchers he has in his fleet.

“The operator presence systems use an electronic module and receive info from the different controls by means of micro-switches and wires to tell the module if the operator was present or not, or if that control was in neutral so it could start the engine. The modules would go bad and switches would break, get out of adjustment, freeze, get dirty… Then we could not even start the engine, and it took a while to figure out which switch it was.”

Solutions vary

Manufacturers of today’s walk-behind trencher models have worked to alleviate this problem through a variety of methods. Some continue to use electronic switches, but have improved their system by beefing up componentry and its protection within the unit.

“Electronics and electronic modules in trenchers have improved greatly over the years — both in reliability and capabilities — which improve operator presence systems,” says Jon Kuyers at Vermeer Corp. “The switches on a walk-behind trencher today can resist contaminants and moisture much better, which caused premature failure in the past. The control modules themselves are also more industrial strength and provide greater capabilities, such as utilizing lights or symbols to identify controls or levers that are out of neutral, which did not allow the operators to start the machine.”

Other manufacturers have opted for moving away from an electronic operator presence system altogether in favor of a mechanical design.

“The more electrical components you have, the more chance you have of something going wrong,” says Matt Collins at Ditch Witch. “In rental, reliability is crucial.”

In 2007 the Ditch Witch organization launched a new line of walk-behind trenchers with a mechanical operator presence system without micro switches and modules. These changes were made to provide a more intuitive and user-friendly product. Ultimately, models are changing and evolving in all areas to meet customers’ needs.

“At the end of the day, we’re doing our best to improve reliability and productivity for our customers,” Collins says. “Manufacturers always have to walk a fine line between sophistication and reliability.”

At Barreto Mfg. Inc., the operator presence system has always been mechanical.

“We do not use micro-switches on any Barreto equipment. We never have – on our older equipment or on our new equipment,” says Jackie Leonard at Barreto. “Micro switches do tend to be a common maintenance item and when we produced our first trencher in 1995, we wanted to provide a solution by having a mechanical answer to operator presence rather than electrical.”

She continues, “The clutch lever we use to engage our hydraulics is our operator presence control. If the operator lets go of that lever for any reason, the wheels and trenching chain stop, but the engine continues to run, eliminating the need to restart the machine to resume trenching.”

Older models still in fleet?

If you own older walk-behind trenchers and are experiencing problems, you might have options.

“On older model trenchers, rental owners should make sure that the machine has the most up-to-date switch for the application,” Kuyers says. “Many manufacturers will continue to support their equipment and make improvements in these areas, if possible, in order to increase uptime and customer satisfaction. However, if the issue is not solved, then it might be time to trade up to a newer unit with the improved switches and modules.”

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