|Fiat Allis 745C >|
Before you have rock to grade,you generally will have to load it and haul it from somewhere. What you see here is a Fiat Allis 745-C made by what is now called FiatAllis North America. This is an intermediate sized rubber tired loader of approximately a 4 yard capacity. A loader is generally said to be matched for size if it will load the haul truck in 3-5 scoops. Quick math will disclose that this size loader is reasonably matched in capacity to the haul trucks that you see on the truck page such as the Payhauler or theM123A1C with a 20 yard belly dump.. This particular machine is of a late 1970's vintage and curiously spent its first life in quite a different job. For many years this machine was equipped with pole forks and bucked poles and piling around in the McCormick and Baxter pole yard located under the St. John's Bridge. It has an extra counterweight and a 3rd spool for the hydraulic system which are necessary for that application. It also has an extra duty brake system. The brakes are air over hydraulic disk brakes, which are split with dual master cylinders and this is followed through dual all the way complete with dual calipers on the disks on both ends. You see, brakes are much more important in a pole yard that at a rock loading site, because at the latter, you always have a pile of rock around to stop you, but in a pole yard, there is nothing that needs to be run over.
Interesting, brakes have always been an issue with rubber tired loaders. They must reliably and repeatedly stop heavy weights. and since all a loader does is run back and forth, brakes get a lot of use. The technology for full air brakes is well understood. It has been used on trains for over 100 years and trucks for 50 years but it has its limitations. It works well with the pressures and configurations characteristic of shoe brakes, but air brakes have a Characteristic which doesn't make it ideal in all applications. Air Brakes are squishy. They do not set up suddenly. They make contact and build pressure to their full application force as the air feeds into the chamber. With the dynamics of a truck or a train this is fine because they are not going to 'stop on a dime' anyway and the modulation reduces skids and shock loads. The requirements of a loader are different though. It needs to be able to drive up and stop precisely a few inches from the truck to dump the load. If the large tires rotate as much as a quarter of a turn while the brakes are setting the loader has moved forward about 6 feet which means that you are just coming out the other side of the truck. The point here is that you need brakes that will lock the wheels suddenly from low speeds. Disk brakes have the kind of braking capacity to handle these requirements, but the action required to set the calipers (which are similar to those found on the front wheels of most cars these days--only larger requires pressures which can not be readily generated by direct action air. Air assist is the easy choice over the vacuum assist used in 'power brakes' in automobiles because the pressures generated by air are much higher than those available in a vacuum assist, and, of course, because there is no ready source of vacuum on a turbo charged diesel engine. You see on a traditional gasoline engine the intake manifold runs a good vacuum level so with a gasoline powered vehicle there is a built in vacuum supply for power brakes by simply running a hose off the intake manifold, but diesel engines have no throttle body and even the naturally aspirated ones don't have all that much vacuum in the intake manifold, and, of course, the turbo charged ones, by definition have a pressurized intake manifold. For this reason, the air assist on the hydraulic disk brakes is sort of a 'no-brainer'.
This machine also varies from the standard configuration in that it has the optional larger 26..5x25 tires instead of the standard 23.5x25 tires. Machines of this type (with folks) can be used to load logs in the woods, but generally they are not, because the landings are usually too small for them to have the 'running room' they need. Bucket loaders such as this machine are relatively new to the machine world.
We give Wagner credit (see the Skidder page) for developing the articulated design for loaders in the 1950's, and a time when rubber tired loaders generally were very rare. Indeed, into the early 1960's Allis Chalmers was making rubber tired loaders that were steered instead of articulated, and generally these loaders were not large. Hough, Michigan, and even Caterpillar made steered rubber tired loaders before then began making articulated ones. Arch typical of the steered machines is the Allis Chalmers TL-30, however the first one this writer recalls seeing was a somewhat smaller Hough with a Hercules engine in it.
Indeed in the 1950's and for many years before that, a power shovel (steam shovel) was the standard for loading aggregate. It was only the development of rubber tired scoops of a size class larger than this (7-8 yard) that put the cable controlled power shovel into the scrap yard. Now, of course, there are 15-20 yard loaders and even larger being made. That seems large, but if you have a 100 ton haul truck, and want to efficiently fill in 3 to 5 scoops that is what is required. It is all a matter of scale.
In many ways, however, the front end loader has fallen out of favor for general construction work in favor of the excavator. It is sort of a full circle in machine usage. We used to have cable shovels loading trucks. Then we saw lots of scrapers, and large front end loaders loading trucks. Now hydraulic excavators have displaced (but not completely) both front end loaders and scrapers on many construction jobs. In order to load with a front end loader the material needs generally to be dug loose and piled with a dozer. by contrast the excavator will dig its own material loose, and while a larger ripper dozer such as the Fiat Allis 31 will handle harder rock than an excavator, the latter will still work under moderately difficult conditions. For example, a heavy excavator such as the Hopto 900A will dig through rock just about as well as a light rock dozer such as the Fiat Allis 16B particularly if the dozer of this class lacks a ripper. The advantage that the Rubber tired loader has over the excavator is that it can not only load, but it can also transport material practically for short distances. For example, one would use a loader to feed a rock crusher because the task usually involves transporting the material as well as scooping it up. In another application, there is a very special breed for low profile loader used for tunnel mucking, however the most common and proper use of a front end loader is to load out of a pile.
The tires represent a major operating cost for a front end loader and consequently if one is thinking of loading rock with a front end loader the tire costs need to be contemplated carefully. A careless operator who charges a rock pile and spins the wheels while filling the bucket can leave some serious chunks of rubber on the quarry floor. While a careful operator can nearly always fill the bucket without spinning the wheels, and peeling off the tread of tires that cost thousands of dollars each, not all operators are so careful. It's harder to destroy an excavator, but it's not that you can't. The way you maim an excavator is to slap the sides of the ditch banks with the side of the bucket while swinging, or slap the side of the truck (which usually doesn't help the truck either). These swing slaps over stress and ultimately crack and break the excavator booms because of the twisting pressures they apply.
Interesting these larger loaders have their place in the timber industry, but it is not in the woods. It is at the truck destination. The loads of logs properly need to be removed from the log trucks in a single bite with the forklift. A load of logs may weigh in the range of 60,000 lbs which is equal to quite a few yards of aggregate at 3,000 lbs to the yard. A machine that charges loads of logs doesn't need to be quite as strong as one that charges rock piles, but it surely needs to handle a log of weight. This is why our 745-C which was a former pole handler was beefed up with an extra counterweight, and oversized tires and extra brakes.
|Main Frame cut to 4 pieces|
|Further cut to #1 scrap almost|
Every machine has it's time. What you see here is actually a frame that we had to buy in order to get the bucket. The guy selling it want the same price for the bucket as he did the frame, axles and bucket so we took the whole thing. The axles will be put aside for spares incase we break a planatary or drop a differential, but the frame seems of little value so it is shown here being cut up. Of interest is that we used a large plasma cutter. Notice that the cuts barely burned the paint. This is typical of the plasma cutter and contrasts with an ox-acy/propane torch that heats everything up. Before this goes I'll unbolt the axles from their pieces and take the hinge bushings out and save them for our surviving machine. Plasma cutters are not in fashion for scrapping, but with a big enough one, the cutting goes quickly. Here I used a Lincoln Pro-cut 80 set pretty well open. IT's suppose to cut 1 1/4" and some of the hinge pieces are that. While I suppose that you can technically cut 1 1/4" with it, don't figure on it. One inch and less yes, but I'll use the Ox and propane to finish the job here.