Twin City Truck Develops, Markets Stinger Axle for Vocational Trucks

DANIEL St Onge develops his ideas into viable products for the trucking industry. "I'm an innovator," says St Onge, president of Twin City Truck Equipment Inc near Minneapolis in Lakeville, Minnesota.

As a salesman for a concrete mixer manufacturer, St Onge designed the Tuck-A-Weigh, a flip-down tag axle that was first used in 1984 on ready-mix concrete trucks, he says. The axle design is in use on many ready-mix concrete trucks in the United States. By 1990, half as many ready-mix trucks were in operation as in 1966, but they were hauling twice as much concrete.

But because of the large steel draft arms on each end of the Tuck-A-Weigh, it is impractical for use on many other vocational trucks such as vans and dump trucks. St Onge says his challenge was to provide other vocational trucks with the same weight carrying advantage as ready-mix trucks.

Increasing the Payload An extendable axle designed by St Onge allows the technology used in the tag axles of ready-mix trucks to be used on other vocational vehicles such as dump trucks. St Onge designed and built a prototype of this axle in the 20,000-sq-ft shop at Twin City Truck Equipment.

In 1995, St Onge began designing the axle, which he named the Stinger. Twin City employees on a team that helped with the axle design were Pete Maye, a design engineer; Ralph Winzig, a master welder; and Virgil Oltman, shop foreman.

"For a year, we worked as a group brainstorming and solving problems as we developed the Stinger," St Onge says.

The result was the extendable Stinger axle, which can be installed up to 150 inches farther back than a conventional tag axle that is mounted 52 to 60 inches behind the rear drive axle. When the Stinger is fully extended, the axle spread allows a vehicle with a heavier load to meet federal bridge laws. On a truck chassis with a 237-inch wheelbase, the maximum bridge is 36 feet.

Hydraulic cylinders extend and retract the axle underneath the chassis frame so the truck can perform its vocational function. This is very important for vocational trucks such as van bodies, roll-off hoists, and dump trucks.

"When we designed this axle, I simply found a place to put the wheels," St Onge says.

A nitrogen-charged accumulator cylinder attached to the Stinger axle dampens road shocks from potholes, debris, and other obstacles. The accumulator cylinder has hydraulic oil on one side and compressed nitrogen on the other.

Advantage for Vocational Trucks For two years, a prototype Stinger has been in use on a single axle dump truck used to haul asphalt. This truck has a 64,000-lb GVW with 18,000 lb on the front axle, 18,000 lb on the drive axle, 11,000 lb on one pusher axle, and 16,000 lb on the Stinger. Weight laws in Minnesota provide a grace threshhold of 1,000 lb, which allows this dump truck to have a GVW of 64,000 lb.

An even larger truck has a 25-ft Bibeau dump body with 48-inch sides and an 80,000-lb GVW with the Stinger. Hydraulically operated bars flip up from the Stinger axle assembly when the truck is in the dump mode to support the frame of the truck.

By installing a Stinger axle on a tandem-axle garbage truck with a 49,000-lb GVW, the payload is increased by two thirds, St Onge says. The truck weighs about 35,000 lb and has a legal payload of 14,000 lb. The Stinger adds 2,500 lb, bringing the weight of the truck to 37,500 lb. This increases the GVW of the refuse packer to 61,000 lb, but increases the payload by 9,500 lb for a total payload of 23,500 lb.

"One of the most promising uses for the Stinger axle is in the refuse-hauling business," St Onge says. "If Browning-Ferris Industries or Waste Management installs a Stinger axle on one of their refuse packers, every refuse hauler in the business will want one."

More Route Stops The benefit is obvious for a refuse packer, St Onge says. A refuse packer truck cannot exceed 40 feet in overall length. At each stop on a collection route, a refuse truck picks up about 50 pounds of garbage.

A truck with a legal payload of 14,000 lb can make 280 stops. By increasing the payload with a Stinger axle to 23,500 lb, the same refuse packer can make 470 stops.

"A refuse packer with a Stinger axle wouldn't have to go to a landfill until the end of the day," St Onge says.

In Michigan where higher GVWs are allowed, a milk truck tank with a Stinger axle and seven axles would have a 91,000-lb GVW. Weight laws in Michigan allow a vehicle to haul 13,000 lb on each axle with up to 11 axles as needed. A single-axle milk truck with a Stinger axle can haul a 60,000-lb payload in Michigan.

Many applications for the Stinger axle exist in the bulk transportation business, St Onge says. The money earned by a bulk-hauling fleet depends partially on how lightweight the trucks are. Fleets often spend a lot of money on lighter aluminum components such as fuel tanks and wheels.

Saving Weight in Bulk To save one pound of weight on a bulk-hauling truck, the average expense in this industry is $5 per pound, St Onge says. For the $18,000 price tag of a Stinger axle, the payload of a straight truck can be increased by 9,000 lb. The Stinger can save one pound of weight for $2 compared to the average cost of $5 per pound.

Besides bulk transportation, the Stinger axle is ideally suited for other vocational applications, St Onge says. Trucks and trailers that deliver frozen meat to restaurants often cannot stack the product more than one pallet high because of its weight.

A chassis with a large refrigerated van body and a Stinger axle could haul a load of frozen meat several pallets high, which could be a larger load than is hauled in a refrigerated van semitrailer. Depending on the weight of the chassis, a 24- to 30-ft refrigerated van body could haul up to 45,000 lb. A typical payload in a 48-ft refrigerated van trailer is 40,000 to 45,000 lb.

Vans with Stingers have an added advantage because they are much easier to maneuver in city delivery situations than a van semitrailer.

"It is critical for a vocational truck to maneuver easily in and out of a job site," St Onge says. "A Stinger doesn't change the steering radius of a straight truck."

City Delivery Trucks In many vocational applications, a straight truck with a Stinger axle offers advantages over a tractor-trailer combination because of its high payload and tighter turning radius, St Onge says. Another advantage is that a straight truck cannot jacknife like a tractor-trailer combination and typically has a shorter stopping distance.

As an added convenience for city delivery vans, on-board scales in production models will automatically extend the Stinger axle when the extra weight-carrying capacity is needed.

Twin City developed its own data from five Stinger prototypes that currently are in use and have logged about 200,000 miles, he says. To date, St Onge has invested $300,000 developing the Stinger axle and bringing it to market. In October, a design patent for the Stinger axle was issued to St Onge.

Stinger Axle Patent "The claim of the axle being retracted underneath the truck frame gives us broad protection," St Onge says. "What makes the Stinger axle special is that it is self contained."

During development of the Stinger, material and component suppliers aided St Onge's efforts. A hydraulic valve manifold to sequence the Stinger axle was developed by the Component Engineering Company in Chanhassen, Minnesota. The manifold switches the valves needed to operate three hydraulic cylinders that deploy the Stinger.

Hydraulic power is provided by a fanbelt-driven pump mounted on the engine. The pump is a six gallon-per-minute self-compensating model.

Primary Products Besides its Stinger axle, the primary products sold and installed by Twin City include Bibeau dump bodies, Tafco flatbeds, Mailhot hydraulic cylinders, and Auto Crane truck-mounted cranes. Twin City recently became a distributor for Chagnon refuse bodies and roll-off hoists.

One of the most popular products sold and installed by Twin City are Bibeau dump bodies manufactured in St-Felix-de-Valois, Quebec, Canada. Bibeau dump bodies are available for trucks ranging in size from one-ton chassis to heavy-duty 80,000-lb GVW chassis.

Twin City was the first Bibeau distributor west of Ohio. The distributor overcomes the freight disadvantage of selling Bibeau dump bodies by focusing sales presentations on product quality.

Floors of Bibeau dump bodies are made of 400 brinnel alloy steel, sides are 500 brinnel alloy, and long sills are 250 brinnel alloy, St Onge says. The unibody construction of the dump bodies makes them among the strongest available.

Sole Stinger distributor Unlike other products sold by Twin City, the company is the sole distributor for the Stinger axle, St Onge says. Twin City does all sales and installation of the Stinger axle.

The Stinger axle is expected to create a regional, Midwestern market for Twin City Truck Equipment so the company can expand beyond its local market, St Onge says. In the meantime, the distributor's current focus remains as a full-line truck equipment distributor.

"The potential market for the Stinger axle is great," St Onge says.

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