Every logging contractor who runs skidders wants to maximize production per gallon of fuel burned. Two recent upgrades help John Deere skidders do exactly that.

Deere has enhanced its product line with a new lockup torque-converter option for the 640H and 648H Skidders and a standard brake declutch on all direct-drive skidders. "The lockup torque converter is very popular on our 848H Skidders, we applied the same concept to the 640H and 648H," said Elizabeth Quinn, John Deere skidder product marketing manager.

Higher Production
The lockup torque converter gives skidder operators a significant increase in productivity versus a standard torque converter. Indeed, Quinn says, the more a skidder operates in lockup mode, the more work it will get done, because the lockup unit increases the power that reaches the ground.

The Deere lockup torque converter stays locked during shifting and through a wider range of ground speeds than competing units. That maintains machine momentum through shifts and helps ensure a smoother ride, with less power lost between the engine and the ground.

In a productivity comparison, a 648H Skidder with the lockup option moved 24.4-percent more tons per hour under maximum load than a unit of the same size equipped with a standard torque converter. "Assuming a usual 14 truckloads per day, that's an extra three loads of logs going to the landing each day," Quinn said.

What's even better, the 648H with lockup torque converter boosts productivity without an increase in horsepower. The skidder continues to be rated at 184 horsepower, with six forward and three reverse gears. But more available power is now delivered to the ground, particularly in lower gears.

Brake Declutch
The brake-declutch feature, previously standard on all John Deere torque-converter and lockup torque-converter skidders, is now standard on direct-drive 540G-III, 548G-III, 640H, 648H, and 748H Skidders.

"With the flip of the brake-declutch switch, operators no longer have to work the clutch pedal or the forward-neutral-reverse shifter when using the grapple," Quinn said. "That makes the skidder easier to operate, which improves productivity." The clutch pedal is retained to provide machine control when needed, particularly for inching during forward and reverse in more precise operations.

Three factors put the H-Series at the head of the class when it comes to fuel efficiency, says Quinn. One is the direct-drive transmission. "With a direct-drive transmission, you lose less power than with a standard torque converter transmission or a hydrostatic-drive system," says Quinn. "Direct drive is a more efficient way of transferring power to the ground. Direct drive gives the operator the ability to put the machine in the right gear. He can downshift or upshift to run at the proper engine speed for the terrain."

The second factor is smart weight management. "The H-Series has enough weight to be extremely productive, but we don't add extra weight that you don't need to haul large loads," says Quinn. "Plus, our lighter weight allows a logger to get into the woods sooner after a rain. Our competitors with heavier machines have to wait a day longer to go to the woods."

Thirdly, the John Deere H-Series uses Exhaust Gas Recirculation (EGR) to achieve Tier 3 emission standards. EGR technology recycles exhaust energy from the engine and puts it to work, Quinn says. The result: improved efficiency.

Turbocharged Service
For H-Series Skidders, improved productivity and efficient service go hand in hand. Here are some examples of how Deere has improved serviceability on the H-Series:

• Remote-mounted engine, hydraulic, and transmission filters are positioned for easy access.
• The cab can be hydraulically tilted sideways to provide unrestricted access to all critical components.
• Engine oil-change intervals are 500 hours.
• The hydraulic oil cooler and air-conditioner condenser swing out for easy cleaning.
• The side-by-side cooling-system design allows access to all coolers for cleaning.

With their PowerTech Plus Tier 3 engines, the new Deere H-Series engines pack more power and torque than their predecessors. These six cylinder engines boast new features such as a variable-geometry turbocharger, power bulge, four-valve cylinder heads, and a high-pressure common- rail fuel system, which each contribute to improving engine power and machine performance, while improving fuel used per ton of wood moved. Power ratings, fuel economy, torque levels, transient response time, and other features meet or exceed Tier 3/Stage standards.

"Our new H-Series Skidders are the most fuel-efficient and productive machines in their class --bar none," says Quinn. "As John Deere himself said, 'I will never put my name on a product that does not have in it the best that is in me.' And that's what we give you with the H-Series -- the best that is in us."

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