Neenah Enterprises Secures Patent for Trench System Improvement

Neenah Enterprises Inc. (NEI) is helping prolong the life of municipal drainage systems with a recently approved patent. NEI manufactures grates that bolt onto frames covering trenches that carry away storm water from parking lots and roadways. The patent is for a debris chute that helps avoid the problem of the bolt holes filling with dirt and sand. Instead of the debris gathering at the bottom of the bolt hole, the chute allows it to fall straight through into the trench below, keeping it from interfering with tightening and adjusting the bolt.

“We’d been hearing about occasional problems with bolted trenches beginning to lift away from the concrete, creating a gap between the concrete and frame,” says Steve Akkala, P.E., manager of technical support and product development for NEI. “The simple adaptation of creating the chute doesn’t cost any more to produce, but is a better way of handling the problem, and helps the system last longer.”

Akkala, who has been an engineer with NEI for 33 years, says that when debris gathers at the bottom of a bolt hole, it prevents the bolt from turning down completely and properly holding the grate to the frame. Installers may try to use more force to turn the bolt, which puts more force on the frame, causing it to separate from the concrete. Or, the installer may end up shearing the bolt off.

“Once the frame starts moving, it may break the concrete. Then, vehicle traffic starts everything vibrating, and soon the frame will work itself out of the concrete,” says Akkala. “The whole trench system winds up needing to be rebuilt.”

In addition to the debris chute that lets dirt and sand harmlessly pass through the bolt hole, the patented system includes a bent rebar that helps better hold and anchor the frame. The rebar bends down into the concrete, which keeps the frame firmly in place.

This latest patent is one of nearly a dozen Akkala has secured for new and improved designs of municipal castings during his tenure at NEI.

Source: Neenah Enterprises Inc.