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Log loaders keep evolving. I'm not quite sure how to put them in generations or even how to organize the log loader section. If this section seems disorganized it is because it is. We have seen log loaders evolve from a several things which makes tracking them difficult. Several pages in this section are devoted to Prentice. This company developed the knuckleboom loader. Meanwhile, out West folks were using modified 'shovels' to load logs. A "shovel" in historical terms refers to what as a child I called a "steam shovel" though I never saw one with a steam engine. In any event, it was usually on tracks and you could mount various 'fronts' on it. As a material loader the machine would have a 'shovel front'. This differed from a backhoe in that it the bucket was turned around and it dug pulling away from the machine instead of towards the machine. Into the 1950's they were standard solutions to loading rock or dirt out of a pile.
Occasionally someone would take the bucket off of a 'shovel' and replace it with an air operated grapple, and call it a 'scissor boom' loader. Anyhow these shovels worked with cables, and about all that remains today is the name.
The 1960's and '70's saw the 'shovels' change into what we now call 'excavators' and become hydraulic controlled. Classic names in American history of shovel makers included American, Bucyrus-Erie, P & H, Link-Belt, Kohring, and a number of others. They all produced hydraulic products and gradually began the transition away from the mechanical drive behemoth that we knew as a shovel to what we know as an excavator. Uniformly however, then didn't move fast enough, and in the recession of 1980 they were all rolled over by a wave if light, fast and less expensive Asian imports.
Most of these classic names disappeared, or at least bailed from the excavator market. Link-belt regrouped and used its strong market position to simply become a marketer for an Asian import. Indeed the same product is sold in this country under several names you would recognize with only the paint and the decals being different.
I tracked some of the Pre-1980 innovations in my discussion of the American 35A Loader as well as the Hopto 900a and the American 35 These new wave Asian excavators, and ultimately loaders are different all the way through.
Gone were the noisy smoky 2 cycle Detroit Diesel engines. In their place we find Isuzu, or Mitsubishi or more recently Cummins engines. These light weight high performance engines do nothing but turn a hydraulic pump. The pump is the next change. Gone on the classic 'gear pumps' which operated at about 2000 lbs. PSI and in is a high pressure hydraulic system working at 4000 PSI or more. Doubling the pressure implies stronger hoses and the like, but also implies that you have to move half as much oil to do the same work, and the cylinders only have to be half as large etc. This allowed the machines to get smaller, lighter, and faster. Then the controls changed. I have recounted how the Hopto, and the American 35 had manual controls---long levers connected mechanically to the main spool valves--and you had to pull hard. The next generation of controls are called 'piloted controls'. In this context the operator works a 'mini' control system that activates the 'real thing' Kohring went with air pilots. The operator had joy sticks that when moved tripped air valves that used air pressure to activate the main spools. The American 35A had hydraulic pilots which used a mini-hydraulic system to move the spools on the main system. Both of these approaches require a lot of plumbing. The Asian wave brought electric pilots. In this approach, you have joy sticks plugged into a wiring harness. These work pretty much on the same principal as the gas gauge in your car---the motion of a float in the gas tank up and down translates into a needle that moves back and forth on the dash board. The nice thing about the electric controls from a user standpoint is that they feather nicely. If you want to move the boom 2 inches you can.
On the bottom side, high pressure hydraulics powered drive motors that make the machines as agile as and fast as a bull dozer, and then there are the tracks----The asian supplies uniformly used bulldozer tracks as they didn't have a vested interest in the old clunky 'shovel tracks'.
As for the Link-Belt's, you will find the 1970's models with a Detroit in them. Instead of putting the engine in the machine crossways as has been popular, I've seen a couple larger models (the 5800) and another even larger one that had a Detroit 8V-71 set with the pumps forward and the radiator toward the counterweight. Link-Belt finally got it right (almost) with the CII series which was produced from 1989 to 1995. This proved to be a very popular machine with only a few nagging problems. One was the undercarriage. Early models have tiny carrier rollers set very low. This left no place for mud,and they packed in quickly and then didn't turn. Improvements elevated the carriers, and put a larger roller in (and added a link to the tracks (to 51 links from 50).
The Quantum line replaced the CII in 1995 and had a production run until 2002. Changes over the decade were not dramatic. They moved from the Isuzu engine to the Cummins C8.3 (and then in 2002 back to the Isuzu). The Quantum line had a bit smarter computer, and a heavier undercarriage, but overall these machines are more alike than different.
That brings me to the 'computer', yes in the heart of the Link-Belt is a computer. What they did with the computer is to add some fuel economy modes that back off the engine when it isn't being used, take advantage of the electric controls to permit intelligent 'flow control'. For example, if you want to lift and swing, you want the boom to get up by the time the swing is complete. Of couse, sometimes you are only swinging a quarter turn, and other times you are swinging a full 180. A switch lets you readjust the flow divider to accommodate this issue.
The Logmaster series incorporates a series of aftermarket modifications to the basic excavator model which make it quite different from the excavator. Several parties make aftermarket 'logger' conversions to the basic excavator. Pierce, Young, and Jewell are among the most common in this area. Deere is actually making their own conversion packages in Langly, B.C. The logger aftermarket package consist of several things:
Of course, a Link-Belt loader isn't a Link Belt at all. Link-Belt is an old line American crane maker which has been gobbled up by a machine conglomerate ultimately owned by Fiat. The Link-Belt excavators are identical to the Case excavators (Case is owned by the same conglomerate), and Case doesn't make them either. They are Japanese machines (like most excavators on the market today) which are private labeled.
Beginning in 2002, Link-Belt (and Case) abandoned their numbering system and joined the industry wide trend on assigning model numbers based on the metric ton weight of the machine. The occasion for the new models was the introduction of Tier II emission controlled engines, and a switch from Cummins back to Isuzu engines. The only thing that remains of the Link Belt traditions in the new models is the classic Red and White Link Belt Color. Everyone else in the industry, it seems, has drifted to some shade of Yellow.