Tier 4 Final Engine Innovation: Caterpillar Launches D Series Skidder Designed to Boost Productivity and Lower Costs

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Tier 4 Final Engine Innovation: Caterpillar launches D Series skidder designed to boost productivity and lower costs

More than just a new series of machines, the innovative D Series Wheel Skidder by Caterpillar Forest Products demonstrates that new emissions compliant designs can deliver on performance, productivity and operational costs. Building on its more than forty years in the industry, Caterpillar recently rolled out its D Series machines after four plus years of testing and development involving input from loggers, dealers and experts in the field.

Major improvements from the C Series include a six-speed transmission with more gears in the working zone, lock-up torque converter and independent front and rear differentials for more pulling power and control, high capacity cooling system and reversing fan, a roomy, quiet and cool operator station and tilting cab for servicing. The engine also meets U.S. EPA Tier 4 Final emission standards.

“The D Series out pulls other skidders. It is also more stable and agile and gives the operator a smoother ride because we optimized the wheelbases and the component layout,” said Matt McDonald, product specialist for Caterpillar Forest Products. “The customer has a more versatile machine that is highly effective in sensitive applications such as first thinnings while maintaining the stability for working in tough conditions.”

One of the operators who was part of the test program, Ricky Jackson of Jackson Brothers Logging in Rutherfordton, North Carolina, commented, “Caterpillar has been very responsive in listening to our input. This is one experience where I am very glad to have been a participant.”

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Describing why he liked the new design so much, Jackson explained, “The new cab is an operator’s dream as far as the seat being very comfortable, the cab is balanced well for a smooth ride. It also offers improved visibility making the job easier on the operator too.”

Jackson added that the new design is extremely quiet allowing him to operate near residential areas where noise levels can make a difference.

Jeremy Carter of Carter Logging in Walterboro, South Carolina, stated, “Overall with the changes that they have made having to go Tier 4 Final, the D Series has been a pretty good improvement. The new design stays down better in the front end. It is very comfortable to run. Everything Caterpillar has done to improve the skidder is a plus.”

Carter explained that the new emissions requirements for Tier 4 Final engines were a concern because some feared the design requirements would impact productivity or overall performance. But those fears were proven unfounded with the D Series, which is the first Tier 4 Final compliant full tree skidder released in the U.S. marketplace this year.

A couple of challenges with Tier 4 Final designs are the larger cooling systems and the overall packaging of the emissions system. This is where designing the machine from end to end becomes even more critical. McDonald proclaimed, “We are getting more power, better production and performance out of the D Series. Overall, our test data has proven fuel efficiency improvements of 3-17% by model.”

Caterpillar recently unveiled its new D Series at a special event for its dealer network and the trade press held in the Atlanta area. The event included a tour of the LaGrange, Georgia manufacturing plant where the D Series is produced. This impressive facility focuses on quality control and eliminating any defects through numerous checks along the production process.

Powerful, Efficient Design

The D Series equipped with the Cat® C7. 1 ACERT™ engine is designed to deliver more power than ever before, while still achieving the highest levels of total fluid efficiency, reliability and durability. “The emissions technologies are designed to be transparent, so the operator can concentrate on the work,” McDonald said.

The D Series features a cross-flow configuration and compartmentalization of the engine and cooling system, which maximizes efficiency and reduces debris collection. Carter explained, “With the cooling package turned sideways, the machine does run cleaner. It doesn’t get debris up in the air filter compared to other tractors.”

The same cooling system designed for the largest model is equipped in all models boosting efficiency even in smaller models. The high capacity cooling system and on-demand hydraulically driven reversing fan keep the machine running at the proper operating temperature, optimizing performance, durability and fuel efficiency.

Unlike some other designs, cool ambient air is pulled in from the side — not from the engine compartment. Air is exhausted out the opposite side. This prevents hot air from circulating and debris from collecting in the engine compartment.

The oversized fan spins at a slower speed, only as fast as needed to maintain proper operating temperatures, and automatically reverses every 20 minutes of run time to blow out debris.

Also, the D Series comes with a six-speed transmission that has gears more evenly distributed in the working zone to maximize efficiency on any terrain and ground conditions. The torque converter allows the machine to ease smoothly into a start when the skidder has a heavy load in the grapple, and then the lock-up clutch automatically engages and the transmission goes into direct drive for high efficiency hauling and up to 15% faster travel speeds in the same gear.

The D Series is easy to maneuver even in dense woods and slippery or steep conditions. In normal operation, all four wheels move independently. In poor ground conditions, the independent front and rear differential locks can be engaged separately for better pulling and maneuverability. The locks are hydraulically actuated and can be engaged on the go.

Heavy-duty Cat axles approved for dual tires up to 30.5L-32 inner and 24.5L-32 outer and wide floatation tires up to 73-44 with chains are standard on all D Series skidders.

Easy to Operate, Maintain and Monitor

When it comes to justifying the reason to switch to the D Series Skidder, the ease of use is a major reason that companies should consider upgrading.

Jackson explained, “Maintenance is much easier with the new design. You can get to things while standing on the ground.” The entire machine was designed so that maintenance is easier to do knowing that it is critical for any machine to run well for a long time.

The new D Series has the little extras that make it popular with operators including a Bluetooth radio. Jackson said that he put a new worker in the machine who was a young adult, and he didn’t want to move to the older machine because the D Series is so user friendly. Jackson said, “The learning curve to figure out how to run the machine is nothing because everything is simple. You have your gears on the steering wheel, it is very simple to operate.”

Cat Product Link™, Caterpillar’s machine monitoring system, is now standard on all forestry machines including the D Series. When installed at the factory, the system comes with a three-year subscription to VisionLink®, the user interface, at no charge.

Product Link is an advanced — but user friendly — remote monitoring technology for equipment. With Product Link, customers know where their equipment is, what it’s doing and how it’s performing. Armed with this information they can maximize efficiency, lower operating costs and improve maintenance tracking.

The system has been in use on many forestry products since 2007. Expanding availability and offering the service at no cost, will allow more forestry customers to experience the advantages of Product link on all their Cat harvesting and extraction machines.

“We know our forestry customers can benefit greatly by using Product Link. This is a tool that can improve their profitability,” said Kevin Thieneman, president of Caterpillar Forest Products.

Because logging sites tend to be in remote areas, information will be transmitted via satellite for more consistent communications. Customers will have remote access to equipment information over the web at any time and any place.

“You want to know what’s going on at your job site? Punch it up and find out. It’s that easy. You get a replacement warning on a filter? Click over to the Cat PartStore™ nd have filters delivered to you the next day. We’re working to better serve our customers in the coming years and Product Link is the key,” said Thieneman.

As part of orientation on a new machine, Cat dealers will provide training on Product Link. Caterpillar also offers online webinars.

“Not long ago people had basic mobile phones and didn’t think they needed anything else. Now everyone’s got a smartphone and can’t live without it. Telematics like Product Link will be mainstream in the near future,” Thieneman concluded.

D Series Specifics

The line has four models to provide loggers with options to match their application and business needs: 203 hp (151 kW) Cat 525D, 225 hp (168 kW) Cat 535D, 250 hp (186 kW) Cat 545D, and the 275 hp (205 kW) Cat 555D.

The new hydraulic system gives the D Series faster multifunctioning capability and greater lift capacity. Hydraulic system pressure boosts of 15% for the 525D and 535D and 23% for the 545D and 555D, matched to the boom length, increase the lift capacity of the D Series. “You can more quickly move your loaders to a new job site and get on with the work,” McDonald said.

The dual function arch and boom is available on all four models. The single function arch is available on the 525D and 535D and cable arch on all except the 555D.

Logging and retrieval winches are available as options. Both are hydraulically driven, have the same pulling power and feature friction style clutches for increased durability over cog-style. Both winches are operated by a joystick for more control over the reeling speed.

The new D Series cab is roomy, quiet and cool with great visibility, especially out the back. The standard Cat Comfort Seat swivels 30° to the right so you can watch skidder and grapple operations. The grapple is controlled through the seat-mounted joystick. “You can rest your forearm on the armrest and have full control of the grapple in your hand,” McDonald said.

A clean three-piece front windshield and tall, wraparound rear windows give the operator a 360° view, including the corners of the blade and winch drum.

The new D Series is certainly setting a new standard in the industry with its innovative design and Tier 4 Final capabilities. For more information visit www.cat.com/forestry or call your local Cat dealer.

D Series Skidder Features

1– Forward mounted engine

• Shifts weight forward without having to lengthen frame for stability on heavy pulls while providing excellent turning radius for thinning applications and easy movement on the landing

2 – Cross-flow cooling

• Gives the opportunity for an extra-large hyd. driven auto reversing cooling fan when not constrained by the front hood dimension

• The resulting segregation of the engine and hyd compartments allows the skidder to pressurize those areas to keep the power components clean

3 – Efficient Powerful Performance

• More gears in the working zone

• Better gear range allows faster cycles to move more wood, resulting in a lower fuel cost per ton

4 – Easy Maintenance

• Tilting cab for easy access to powertrain components

• Access to grapple head components for better serviceability

• Ground level engine service

5 – Comfortable Cab

• Quieter, cooler, more room, more visibility

• High back air suspension seat for premium operator comfort

Product Link Details

With Product Link customers can:

• Know the location and status of equipment, including alerts if their equipment is moved without their knowledge.

• Track fuel use and idle time.

• Monitor equipment efficiency and health, including fault codes.

• Access fluid analyses results and online parts ordering.

• Access model-specific daily safety and maintenance inspection checklists.