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Log Loader

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Forestry Equipment
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2001 John Deere 330LL Butt-N-Topp Log Loader
A log loader is a machine used to load and unload timber from log transportation vehicles and storage piles.[1] While some log loaders are made specifically for loading tasks, others are derived from hydraulic excavators. The purpose-built types are advantageous as they include cabs that can tilt and adjust upright while the loader is traveling on a slope. Stationary loading methods such as the crosshaul can still be applied,[2] but loaders such as knuckleboom loaders and mobile loaders are much more efficient and widely used in the forestry sector today.

Contents

[edit] History

Before the dawn of log loaders as they are known today, hand rolling was employed. In this method, logs were rolled by hand onto a wagon or sled. This was accomplished using a peavy, a hand tool with a hook and a wood handle five to six feet (1.5 to 1.8 m) long—essentially, a wooden lever with a strong spike. The spike was inserted into the side of a log to facilitate skidding the log to a spot from which it could be rolled onto a loading vehicle. This method was extremely inefficient and arduous, and has been replaced with less demanding practices.

Following the hand-rolling method, other methods were devised with the view of loading logs more rapidly, often involving spar trees and guylines to lift logs into their respective loading cars. Gin pole and A-frame loading, for example, were used to lift logs, rather than rolling them, into a load truck using a single loading line. In crosshaul loading, a rope was tied around a log, which would roll when the end of the rope was pulled.[3] The crosshaul is still used today in some smaller applications. It would not be long before steam-powered, mobile log loaders would arrive on the scene.

[edit] Decker Self-propelling Log Loader

This loader, introduced in the early 1900s, was manufactured by the Clyde Iron Works Co. The Decker resembled a small cabin on four legs, and operated on wooden or steel rails. A boiler was mounted on top of its platform and power was supplied to the wheels with the use of a chain drive to move it along the rail spur lines. This loader had portable tracks running through its underside where empty cars would pass through, enabling the Decker to load them continuously with its front-mounted boom. Once loaded, the cars could be connected to a locomotive, and transported to a mill for processing.

[edit] Lidgerwood Portable Logger

Further advancements were made, and by the beginning of the 20th century came the introduction of the Lidgerwood Portable Logger. This massive machine, mounted on a 98-foot  (30-m) rail car, combined the tasks of skidding and loading. On one side of the car was a 98-foot (30-m) steel tower; at the other end, a steel loading boom. The machine’s skidder had a platform that was raised on steam jacks resting on railway ties. The skidder’s car could be removed in order for log cars to be pulled underneath it. The loading boom would then load the cars in succession as they were pulled under the skidder’s platform. This sophisticated machine took a crew of approximately 20 men to operate.[4]

[edit] McGiffert Loader

Soon, the McGiffert loader, named after its developer, was introduced by the Clyde Co. This steam-powered machine was a heel-boom type loader. It was mounted on wheels that could swing up on hinged supports, whereby the loader would be left to stand on four legs resting on rail ties. Empty cars would be pulled underneath the loader in order to be loaded at the front with a fixed boom. These loaders, utilizing a crew of nine men, had the capacity to load 3,270 cubic yards (2,500 m3) of logs in a day.[5]

[edit] Barnhart Loader

The Barnhart loader was a different type than its predecessors. This machine was mounted on portable tracks on the rails cars that were to be loaded. It pulled itself along the tracks using a rope made of wire. This machine’s engine, boom, and winches were mounted on a turntable that could swing 360 degrees; it was the first to do so.[6] Competing companies began to produce variations of this machine, often including gear-driven turntables.

1996 Komatsu PC300HD-6 Shortwood Log Loader

[edit] Logger’s Dream

After World War II, improved loading methods were once again needed in response to increased logging done by power saws and trucks. Arguably, the first such factory-made loader was the truck mounted mobile loader known as the Logger’s Dream, developed by Taylor Machine Works.[7] The Logger’s Dream was mounted on the deck of a two- or four-ton truck, and consisted of a one or two-drum winch and an A-frame. Operators often made use of a mule to transport the mainline tongs out to the logs. The Logger’s Dream used a crotchline, two lengths of wire rope suspended from the end of a loading line and terminating in end hooks. The ends hooks were placed at the end of a log for loading, and workers guided logs onto the loader with ropes. This was an efficient, affordable loader that gained widespread popularity.

[edit] Big Stick Loader

This machine, first introduced by Brown Machinery Service of Louisville, Mississippi, was comprised of a boom, often hydraulically-powered in the more sophisticated versions, mounted behind a truck cab. It had a winch that made use of the truck’s power take-off. Though many inexpensive imitations of this machine were being manufactured, the more costly Brown version was said to be the most reliable.[8] This machine was one of the first to employ a mechanical device that eliminated the need for hand loading pulpwood.[9]

[edit] Knuckleboom Loader

These loaders made their North American debut in 1958 when Bob Larson, a dealer located in Minnesota, bought the rights to a Swedish design. Larson marketed the machine as the Hiabob, derived from its Swedish name, the Hiab.[10] Another knuckleboom loader was being developed around the same time by Leo Heikkinen of Wisconsin. Heikkinen’s knuckleboom was mounted on a trailer towed behind a crawler tractor, rather than today’s common truck tractor configuration. Knucklebooms are one of the most predominantly used types of loaders today, especially in eastern Canada.[11]

[edit] Features/How it Works/Types

Today, there are several kinds of log loaders, each operating in different ways, using different parts and configurations. Knuckleboom loaders are stationary, while other loaders such as crane loaders, forklift loaders, heel boom loaders, and butt-n-top loaders are self-propelled.

[edit] Knuckleboom Loaders

1990 Skogsjan 1088XL 8x8 Log Loader
These loaders, mounted on a trailer and towed by a truck tractor, consist of a hydraulically operated boom (sometimes a converted excavator arm)[12] that imitates the movements of a human arm or finger. It uses two short booms linked with pivots and hydraulic cylinders; one of the booms is attached to a short pipe mast that is located on a truck bed. The end of the boom is outfitted with a hydraulic grapple, and can swing hydraulically in a 190-degree arc. Knuckleboom loaders are efficient and precise in their movement.

Presently, Knuckleboom loaders are capable of increased lift capacity. Such companies as Deere & Co. offer loaders like the 335C with a lift capacity of 23,700 pounds (10,750 kg) at 10 feet (3 m), and a maximum boom reach of 27 feet (8.2 m), and the 437C with a reach of 32 feet (9.8 m) and a lift capacity of 26,100 pounds (11,839 kg) at 10 feet (3 m).[13]

[edit] Self-propelled Log Loaders

Though knuckleboom loaders have been in existence for a half-century and remain widely used, mobile loaders, mounted on rubber wheels or tracks, have become common in log-loading tasks. Self-propelled loaders are sometimes purpose-built, and are sometimes derived from other machines. Tracked loaders that are not purpose-built are often excavator-based, and rubber-tired versions are often based on wheel loaders or rubber-tired excavators. They employ the use of rotating grapples to grasp and move logs.

[edit] Crane Loaders

The machines referred to as crane loaders are essentially specially configured cranes. A standard mobile crane is outfitted with a special loading boom in order to make it suitable for loading jobs. These log loaders include a machinery deck carrying a power unit, a hoist unit with multiple drums, a travel and swing unit, and controls inside an operator’s cab. This machinery deck is mounted on a turntable, enabling it to rotate. Most crane loaders are self-propelled with a diesel engine, mounted on tracks or rubber tires; the turntable can also be mounted on a motor truck. Rubber-tired versions usually include hydraulic outriggers for stability.

Crane loaders are outfitted with a heel boom, which is a loading boom that uses tongs that force one end of a log against the boom’s underside. There are two main types used in crane loading, the more widely used of which is the gooseneck boom.[14] The curved gooseneck boom is built in two segments; the lower section is hinged to the front of the crane. The upper section is configured in such a way that it supports the boom hoist line, which is responsible for raising and lowering the boom. This boom grasps a log off-center with tongs or grapple, and the end of the log is heeled against the underbelly of the boom’s upper segment. The log is unable to slide back further than the bend in the gooseneck.

Hinge-type heel booms are another type used on crane loaders. These booms are straight, and are hinged to a vertical support that is mounted on the front of the crane. The vertical support includes a cab guard projecting from either side. This type of boom has a greater lifting capacity than the gooseneck boom, due to its ability to heel a log closer to the machinery deck.[15]

The booms on crane loaders were traditionally equipped with loading tongs made of forged steel, which are hinged near the upper end. In order to set the tongs on a log, the legs of the tong would have to be separated manually by a worker, and then set on the log. Once the log was lifted and lowered onto a truck, a worker would have to release the tongs manually as well. If tongs were not secured onto a log properly, they could pull off a piece of the log. Additionally, tongs would leave wasteful holes in the log they were lifting. In most jobs, crane loaders eventually began to employ a cable-operated set of jaws known as a grapple to grip the logs.

[edit] Forklift Loaders

These self-propelled loaders were originally adapted from converted front end loaders with buckets, used in earthmoving applications.[16] The loaders were then outfitted with forks. These forks, still in use today, are designed to lower to the ground, slip underneath a log, and then tip backwards to allow the logs to roll back on the loader. To retain the logs, the loader includes clamps that lower onto the load while it is being moved. Unloading involves the opposite process, as the loader is tipped forward and the clamp is released. One of the first machines to employ the forklift method was the Drott Skid-Loader,[17] which was mounted on an International Crawler Tractor. This machine was able to gather a bundle of pulpwood in grapple arms, and, once it had skidded the load to the roadside using the grapple as a sled, it would lift the grapple to load the logs into a truck. Today, forklift loaders are available from such manufacturers as Deere and Company and Caterpillar with their 980 Model, and make use of changeable attachments such as grapple arms to grasp and lift a load of timber.

[edit] Mobile Heel Boom Loader

This log loader is a self-propelled version that makes use of a hydraulic grapple arm. This loader is outfitted with a hydraulic attachment on the grapple that enables it to grasp a log in two places at once, while bringing it closer to the boom, or “heeling” it. This allows greater control of the log that is being loaded. It differs from the heel boom on a crane loader in that the crane-type loader uses cables as opposed to hydraulics, and heels the butt of the log against to the body of the crane rather than simply bringing it closer to the boom.

[edit] Butt-N-Top Loader

This self-propelled loader is outfitted with a specialized grapple. With extensions on either side of the grapple, it is able to grip logs and turn rotate them. By doing so, this loader can load logs on a transportation vehicle or storage pile, alternating the logs’ butts and tops for a secure and steady load.

[edit] Common Manufacturers

[edit] Additional Photos

1996 Link-Belt 2800Q Heel Boom Log Loader
2001 Komatsu PC270LC-6LL Butt-N-Top Log Loader
2003 Liebherr A934 Litronic 4x4 Mobile Log Loader
2005 Kenworth T800 Quad-A Log Loader
T-MAR / Kobelco SK475 Log Loader
T-MAR / Kobelco SK370 Log Loader

[edit] References

  1. Ritchie Bros. Auctioneers. Equipment Valuation Assistant. Ritchie Bros. Auctioneers Incorporated: 2004.
  2. Stenzel, George and Walbridge Jr, Thomas A. and Pearce, J. Kenneth. Logging and Pulpwood Production. John Wiley and Sons: 1985.
  3. Stenzel, George and Walbridge Jr, Thomas A. and Pearce, J. Kenneth. Logging and Pulpwood Production. John Wiley and Sons: 1985.
  4. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  5. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  6. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  7. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  8. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  9. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  10. Drushka, Ken and Konttinen, Hannu. Tracks in the Forest. Timberjack Group Oy: 1997.
  11. Stenzel, George and Walbridge Jr, Thomas A. and Pearce, J. Kenneth. Logging and Pulpwood Production. John Wiley and Sons: 1985.
  12. Ritchie Bros. Auctioneers. Equipment Valuation Assistant. Ritchie Bros. Auctioneers Incorporated: 2004.
  13. Knucklebooms. John Deere. 2008-09-09.
  14. Stenzel, George and Walbridge Jr, Thomas A. and Pearce, J. Kenneth. Logging and Pulpwood Production. John Wiley and Sons: 1985.
  15. Stenzel, George and Walbridge Jr, Thomas A. and Pearce, J. Kenneth. Logging and Pulpwood Production. John Wiley and Sons: 1985.
  16. Conway, Steve. Logging Practices. Miller Freeman: 1982.
  17. Stenzel, George and Walbridge Jr, Thomas A. and Pearce, J. Kenneth. Logging and Pulpwood Production. John Wiley and Sons: 1985.