Putting the arm on refuse: Needing highly repetitive automated cycles, Wittke, Cat OEM Sales develop new automated side-loading system - Mobile Hydraulics

Diesel Progress North American Edition, July, 2003 by Mike Osenga

Automation is the Holy Grail in the refuse collection market. The path toward that grail is automated, single-operator trucks. The benefits of an automated approach to collecting refuse and recyclables are readily apparent; reduced collection work hours, lower operating vehicle hours and as a result, lower total annual costs.

The challenge is in changing customer behavior, especially in residential garbage pick up. Waste haulers have to convince municipalities to organize household trash collection to take advantage of the automation today's refuse vehicles can offer. To do this, many waste collection companies are offering significant price discounts to encourage more automated collection.

The three types of refuse vehicles - front-loading, rear-loading and side- loading -- all have advantages and disadvantages for the various types of refuse pick up encountered. Both front-and rear-loading trucks are widely used in commercial refuse collection. Rear-loading trucks are also widely used as a central processing point, with smaller collection vehicles roaming a neighborhood and delivering refuse to the truck for compaction.

Automated side-loading (ASL) trucks are increasing in popularity, especially in residential refuse collection. The trucks can move down a street, pick up, dump, replace the container and move to the next house without backing in or out.

The potential for single-operator automated collection is significant, and interest in ASL trucks continues to grow. While most popular in the western U.S., interest in ASL trucks continues to grow in new subdivisions, housing developments and retirement communities where automated collection routes can be designed in from the beginning.

One of the major manufacturers of ASL trucks is Wittke, part of Federal Signal Corp. Federal Signal is a manufacturer of refuse trucks, street and parking lot sweeping vehicles, industrial vacuuming trucks, municipal catch basin/sewer cleaning vehicles and water blasting equipment sold under the Wittke, Leach, Ravo, Elgin, Vactor, Guzzler and Jetstream brand names.

Waste Management, one of Federal Signal's major customers and a company that purchases approximately 28 percent of all refuse trucks sold in North America, had some concerns about the hydraulic automated side-loading mechanism on its Wittke trucks. The hydraulic loading mechanism grabs the waste container, raises and dumps it into the truck and returns the container to the curbside.

According to Federal Signal's Bill Krupowicz, group director, marketing, the as-designed hydraulic system gets tweaked to provide ever faster cycle times. This causes the mechanism to become jerky bang against the truck body and cause damage to the ASL assembly itself, as well as the truck body. This results in machine downtime, which affects the productivity of the truck and causes extended mute pick up times. It is also noisier, a special consideration in residential neighborhoods.

"The problem is the mechanism and especially the mechanism arm, which was designed to handle as much as 1300 lb." Krupowicz said. "This is the very worst case scenario and not at all representative of what the truck would see in normal residential operation.

"Plus, the brute force type of hydraulics and controls used in the refuse market are not really designed for the highly repetitive automated cycles needed for these kind of route operations," Krupowicz added. "We needed a control system that would control the arm at the extreme ends of the cycle, especially when emptying the can and replacing it."

As a result, Wittke is now testing and has recently placed its first production order for a new ASL control system that uses an electronic controller, proprietary software and a patented position-sensing cylinder from the OEM Sales Group at Caterpillar Inc. The new system is expected to be on Wittke trucks by the third quarter of this year. It was first shown to the refuse market at Waste Expo in New Orleans in June 2003.

The Wittke ASL control package represents a debut of sorts for Caterpillar's OEM Sales Group, especially on the hydraulic side. According to Rik Doro, marketing manager, Cat Hydraulics & Hydraulic Systems, the OEM Sales Group is responsible for providing deeply integrated systems such as the Wittke control system.

Doro and Andy Dlugokecki, hydraulics business development manager, said the group can draw from all of Caterpillar's products and technologies. These products include electronics, hydraulics, engines, transmissions, undercarriages, cabs, testing and logistics. Additional details on Caterpillar's OEM Sales Group will be detailed in a future edition of Diesel Progress.

The new ASL package will control nearly identical automated side-loading assemblies on Wittke's Automated Side Loader and Crocodile models, both built in Medicine Hat, Alberta, Canada. The Automated Side Loader has a 5.0 cu.yd. hopper that allows between six to eight pick ups before triggering the pack cycle and has a body design based on Wittke's front-loader truck. The packer and automated side-loading assembly are powered by a fixed displacement pump driven off the front of the engine. There is a separate pump for the lift arm circuit.