VPAT Standards for Variable Pitch Angle Tilt. Often shortened to PAT Blade. Versatility is a key feature of VPAT Blades. They can handle a variety of applications from site development to general dozing work. Blade lift, lowers, angle and tilt are controlled with one lever. Foldable versions of this blade type are also available to facilitiate machine transport in width restricted areas. VPAT Blades can be mechaniclaly tipped forward for improved penetration or to shed sticky material tipped backward for finish grading and improved productivity.
SU Blades combine the desirable characteristics of U-Blades and S-Blades into one. The addition of short wings increases blade capacity. The wing provide improved load retention while maintaining the blades ability to penetrate and load quickly in tighly pakced material, and to handle a wide variety of materials in production applications. Equipped with a push plate, it can be effective for push-loading scrapers.
This blade is best for lighter or relatively easily dozed material. The large wings on this blade make it the most efficient for moving large loads over long distance. Applications include land reclamation, stockpile work, charging hoppers, trapping for loaders, overburden removal, landfill and stockpiling of coal and woodchip piles.
Straight blades provide excellent versatility. Because they are smaller than SU or U Blades, they are easier to maneuver and can handle a wider range of materials. S Blades are more aggressive in penetrating and obtaining a blade load, plus they can handle heavy material easily.
The Komatsu Sigma Dozer Blade is the Komatsu improvement upon the Caterpillar SU Blade. The Sigma Dozer Blade reduces digging resistance and smoothly rolls material up for increased blade loads. The middle section of Komatsu’s Sigmadozer® blade acts like a V-shaped bucket with aggressive ground penetration. Its lateral blade edges help to push the rolling material continuously towards the centre. Combined with the blade’s deep curve this largely increases effective capacity and reduces spillage and fuel consumption. The blade’s fl at cutting edge and the standard pitch function also offer top grading performance. Overall, the Sigmadozer® blade increases dozing productivity by more than 15% compared to a conventional Semi-U blade.
Caterpillar actually holds the patent for the high-drive track-type vehicle design, which was assigned to them back in 1974.
There are several advantages to the high track design unique to the Caterpillar Dozer range. Firstly, the higher cab placement of the high track design dozer gives better visibility to the operator. The dozer blade on a high track machine also lifts twice as high which is ideal for forestry application involving stick raking or tree pushing.
It is also easier to clean the tracks on a high track dozer, and the drive sprocket is kept out of the ground which reduces exposure to abrasive material/mud/rocks and therefore prolongs undercarriage life. Maintenance on a high track dozer is also a major plus. The sprocket comes out in three pieces without breaking the track. Repairs are also easier to undertake on a high track machine: removal of a final drive on high track is 4-5 hours – versus jacking up and breaking the track on an oval track machine which can take 1-2 days.
On an oval track machine the loose track is either in front of or behind the drive sprocket depending on reverse or forward operation, whereas on a high track machine the track remains tight in front of or behind the elevated drive sprocket at all times. This is important is hilly applications and another instance where a high track dozer is very advantageous. When reversing up a hill on a conventional oval track dozer, the tracks are driven by the sprocket located at the back of the machine. What this therefore means is that since the sprocket is rotating anti-clockwise to achieve the reverse operation, the track will tend to have slack under the rollers – opening up the possibility of the track coming off the rollers if the operator attemps any sort of turning while reversing. In comparison a high track dozer keeps the tracks tight on the ground – whether in reverse or forward, which allows the operator to turn on steep ground safely.
Overall a high track machine is much more stable and has 25% more rail than a standard oval track. The ground speed is also much higher due to this fact. In terms of machine tip-over risk on high track machines, this is mostly hearsay as the powertain sets just as low as an oval track machine. In addition to this, the final drives and gearbox are located to the rear of the machine which acts as a counterweight and improves stability of the machine.
Available in multi-shank or single shank. The 2 vs 4 barrel difference in rippers is harder to understand until you see it spelled out. The reference to ‘barrel’ refers to hydraulic cylinders. A 4 barrel ripper will have 4 hydraulic cylinders on it. A pair of them will be placed diagonally across the parallelogram to raise and lower the ripper bar by pulling the upper front and lower rear corners of the parallelogram together, etc. On a 4 barrel system, the upper linkage will also be hydraulic cylinders. This permits the operator to adjust the angle of attack of the ripper points. This is critical in hard ripping because as the point wears you can adjust it to get a new bite. This will greatly extend the useful life of the ripper points which are both expensive and extendible.
Available in multi-shank or single shank. The Adjustable Parallelogram ripper can vary the tip angle beyond vertical for improved penetration and can be hydraulically adjusted while ripping to provide the optimum ripping angle in most materials. All modern tractors use adjustable parallelogram rippers, available in single shank and multi-shank arrangements. The single shank models are built for the toughest ripping work, where maximum penetration and depth is required. The multi-shank arrangement will accept three shanks for use in less dense materials.
The multishank ripper is intended as a high production ripper in hard-packed soils and for loosened embedded rock. It is intended to be used in material that can be ripped with at least two shanks. It is intended for applications where ripping with a single center shank is required less than 20 percent of the time. It is not intended for high production ripping in rock with a single center shank. One shank should be used in material which breaks out in large slabs – so the slabs either fracture or pass around the single shank. When two or more shanks are used in this situation, the shank can act as a rake and wedge the larger slabs under the ripper beam. Or, as often happens when using two shanks in difficult materials, one of the shanks may become stalled by a hard spot. This causes off-center loads to be placed upon the ripper beam and mounting, and thus the tractor. A single shank can be used in the center pocket of a multishank ripper in order to gain penetration in more difficult material. The multishank frame provides the flexibility to achieve the greatest ripping production in various strengths of materials. The use of only one shank centers the load in the beam and mounting assembly and allows full force to be exerted at a single point. Even if the material can be handled by two shanks, production can often be increased by using a single shank for smoother operation and less slippage and stalling. Two shanks can be most effective in softer, easily fractured materials which are going to be scraper loaded. In some cases, two shanks may be required by job conditions such as ripping along a high wall or the toe of a slope. Three shanks should be used only in very easy-to-rip material such as clay hardpan or soft shales.
A deep rip shank should be used where laminations or other places of weakness exist
that cannot be reached with the standard length shank. These longer shanks also have the potential to produce greater volume per ripping pass in many materials compared to a standard single shank. Common applications include relatively easily ripped material such as clay hardpans, coal, and some sandstones and shales. Caution must be applied when using deep shanks in harder material, because the extra shank length reduces their ability to handle ripping loads when compared to conventional shanks. These shanks are designed for light to moderate duty and therefore can break when used in the extended positions in hard material.
Rock that is extremely difficult to penetrate and rip can often be lightly blasted (called “preblasting” or “pop” blasting) and then ripped successfully. In many applications preblasting can provide cost and environmental benefits over complete blasting. The procedure simply involves light charges on wide centers to improve initial ripper penetration. Ripping normally then has the advantage of fracturing the material into smaller pieces than blasting. This method has produced cost savings in some applications, but must undergo careful cost evaluation. It is also cost effective in many operations to rip as much material productively as possible and then blast the unrippable material. This allows the operation to move as much material as possible at the lowest possible cost.
Cross-ripping involves ripping an area with a series of longitudinal passes (east to west, for example) and then covering the same area while ripping in a transverse direction (north-south). In general, cross-ripping makes the pit rougher, increases scraper tire wear, and requires twice as many passes; however, it does help break up “hard spots” or material which comes out in large slabs, and will loosen vertically laminated material in which single-pass ripping produces only deep channels. When material is extremely hard to penetrate, cross-ripping will often separate fracture planes set up by the first pass and allow ripper use where blasting would otherwise be required. Cross-ripping is often done to reduce material size to better facilitate scraper loading of the material, or in order to meet crusher throat limitations. When considering cross-ripping, careful analysis should determine if material removal efficiency is increased enough to offset the increased time and expense
Generally, ripping direction is dictated by the job layout. However, there are certain conditions under which ripping direction will greatly affect results. When ripping in a scraper cut, it is always best to rip in the same direction that the scrapers will load. If the rock formation lies in such a manner that cross-ripping is required, the final pass should always be in the direction of scraper loading. This procedure yields several advantages. It greatly aids scraper loading, reduces the chances of damaging or springing the scraper bowl, allows the ripping tractor to double as a pusher in certain situations, and it permits traffic to flow in the same direction. Occasionally, a rock formation will be found containing vertical laminations or fractures that run parallel to the cut, in which case, ripping in the direction of the cut may result only in deep channels. When this occurs, it may be necessary to rip the material across the cut first to obtain proper fracturing, then make the final pass in the direction of the cut. Material such as caliche tends to break out differently than most materials. This “buttercutting” effect lowers productivity and demands additional ripping passes. When applied to ripping, buttercutting is a term used to describe material breakout similar to the slicing of a knife through butter. There is minimal fracturing of the ripped material except in the vicinity of the shank. This can occur in soft or non-brittle materials that display discontinuous breakout. Discontinuous breakout occurs in rock because there are no preferred planes of weakness for a fracture to propagate along. Examples of materials which can exhibit this type of breakout are cemented gravels, caliches, and breccias. It’s also advantageous to rip downhill whenever possible. Gravity helps the tractor take maximum advantage of its weight and horsepower. However, uphill ripping is occasionally used to get more rear-end down pressure or to get under and lift slabby material. If the material is laminated and the plane of the laminations is inclined upward toward the surface, it’s best to rip from the shallow end (where the laminations reach the surface) toward the deep end. This helps keep the ripper tip in the ground. When ripping is done in the opposite direction, the tip tends to “ride over” the laminations and be forced out of the ground.
Proper gear and speed selection is critical to obtaining maximum ripper production and efficient tractor operation. Generally speaking, first gear is used in most ripping situations because a speed of 1 to 1-1/2 mph, at about 2/3 throttle, gives the most economical production. Just a small increase in speed above the optimum can result in ripper tip wear, excessive track slip, and ultimately in lower production and higher costs. Excessive speed generates excessive heat at the ripper tip and greatly shortens tip life. Therefore, when ripping in easy-to-rip materials, it is better to rip deeper at regular speed or use two or three shanks than to use one shank and increase ripping speed.
Ripping depth is normally determined by job requirements, material hardness, bedding thickness and degree of fracturing. Ideally, ripping with standard shanks should be done at the maximum depth that penetration and traction allow. This results in maximum production per unit of fuel and tip wear material used. Sometimes, however, it may not be practical to rip at maximum depth. When opening a cut on a very hard or smooth surface where grouser penetration is limited, making a series of shallow cuts significantly improves traction and penetration by providing a “bed” of loose material for the track grousers to grip. Or where considerable stratification is encountered, it is usually best to rip and remove the material in its natural layers rather than try to make a full-depth pass. An initial pass at less than full-depth will often break the material loose so that the second pass can be made at the optimum depth and achieve more complete fragmentation. Ripping depth and the number of shanks to be used should be considered together. While deep ripping with a single shank usually yields maximum production, many soft or thinly laminated materials can often be better handled by multiple shanks at a more shallow ripping depth.
Using the correct shank angle during the pass is very critical to ripper production. For best results in most situations, follow these guidelines. Adjust the shank angle forward until the tractor feels “pulled into” or pinned to the ground. Due to shank design, a shank angle that may appear to be too far forward can actually be in the best position for ripping. The ripper tip should be slightly below the heel of the shank.This angle is best for ripping because the force exerted on the small area of the tip initially fractures and weakens the material. Then as the shank passes through, the material is shattered from the bottom to the tip. If the shank pitch angle is too far back (not moved forward enough after penetration), it causes the tip to drag across the rock and puts the face of the tip and shank in contact with the material being ripped. This results in excessive wear and increased resistance, lifting the rear of the tractor, so that traction is lost and ripping effectiveness reduced. Operating with the shank angle too far back is the most common error made by ripping tractor operators. For parallelogram rippers, the operator can estimate when the shank is in the best ripping position by observing the tilt cylinder rods. After finding the best ripping angle for the material you are working in, see how much of the cylinder rod is extended and use this as a guide for future reference. At the proper shank angle, the tip will penetrate and split the rock much as a wedge is used to split a log. At the same time, this will help keep the tip short by wearing more on the bottom surface than on the top. It’s also very important to avoid moving the shank too far forward. This permits the tip to rise above the shank heel, resulting in rapid heel wear and loss of penetration.
Sweeps are used in forestry applications to provide additional guarding. Constructed of formed steel tubing, they are mounted on the tractor with rubber isolation mounts for vibration and shock resistance. Sweeps are designed to protect only the tractor itself; they do not provide additional falling object protection or rollover protection for the operator.
Window screens help protect windows from breakage during land clearing applications or when a tractor is equipped with a winch.
Sealed and lubricated track chains have counter-bored track links. They also have polyurethane seals that seat in the track link counter bore and make contact with the bushing ends when the track links are pressed together. The polyurethane seals keep lubrication sealed between the pins and bushings, and keep abrasives out. Lubrication provides a film of oil between the pin and bushing internal contact surfaces, reducing friction and virtually eliminating internal pin and bushing wear. Elimination of the pitch extension slows down sprocket tooth wear and bushing outside diameter wear. Sealed and lubricated chain life is approximately 50-percent longer than for sealed track chain. Sealed and lubricated track chain not only reduces bushing outside-diameter wear and sprocket tooth wear, it reduces noise and increases machine fuel efficiency. No matter what type of track chain you have, the track pins rotate approximately 180 degrees on the inside-diameter surface of the bushings as the track chain pivots into and out of the sprocket and idlers. On sealed track chain, wear will occur on about 180 degrees of the track pin outside diameter and bushing inside diameter. On sealed and lubricated track chain, lubrication virtually eliminates this wear.
Caterpillar’s SystemOne undercarriage takes much of the friction (and subsequent wear) out of the track-chain assembly by lubricating the pin-and-bushing joint and by allowing the bushing to turn while under load in the sprocket tooth. The pin and bushing in the SystemOne undercarriage actually form a sealed, internally lubricated cartridge. The SystemOne chain is composed of box sections — two links turned in and pinned together by two cartridges. Each box section is attached to the next by a pair of links facing out. (All the links are identical.) The inner links are pressed on to the inner portion of the cartridge (the “insert”), and the outer links are pressed on to the cartridge’s outer ends (“the collars”). The outer links hinge around the inner links, effectively eliminating any relative motion between the insert (bushing) and the sprocket tooth. Wear that does occur, says Caterpillar, results from abrasives in the soil. Compared with machines running with a conventional SALT undercarriage, says Cat, many of the 7,000-plus machines now running with SystemOne have exhibited a 50-percent improvement in undercarriage life. According to the company, this improvement results not just from the new cartridge/link assemblies, but also from a redesign of other undercarriage components, such as the Center-Tread Idler, which contacts only the center (insert) of the System One cartridge — not the link rails — and thus avoids a critical source of wear in conventional undercarriages.
Standard Track (EX), wide track (WX) and low ground pressure (PX/LGP) track. On rocky ground, the EX undercarriage, with small-width shoes, ensures maximum contact area between the machine and the ground. The PX version has the widest undercarriage shoes and is ideal for soft surfaces. Finally, the WX machine is perfectly suited for most jobs with medium width undercarriage shoes and the same length of track on ground as an EX model machine. The main benefit of the WX model machine is a larger blade allows for productive capacity, where more dirt can be pushed per blade load.
Select the narrowest track shoes possible — make sure they give you the flotation you need. Wide track shoes used on a hard surface will put an increased load on the track-chain pin and bushing joints, and can affect pin and bushing retention in the track links. Lubricated track chain seal integrity also can be affected. A wider than necessary shoe width also increases stress and load on idlers, rollers, and sprockets. The wider the track shoe and the harder the under-track work surface, the faster track shoes, pins, bushings, rollers, and idlers will wear.
To check chain tension on either an oval-type or elevated-sprocket undercarriage, place the machine in its work environment and allow it to roll to a natural stop in forward. Don’t brake, because the track may bunch up and not yield a true indication of track sag. Place a straight edge across the highest grousers on the upper portion of the track, and then, at the approximate midpoint between the components that are supporting the chain, measure perpendicularly from the straight edge to the top of the grouser below. The optimum measurement should be 2 inches. If either chain uses a carrier roller, make two such measurements. Chances are the measurements will be close, but if not, you’re probably best off adjusting the tightest section of track to the optimum sag dimension.
Reverse operation accelerates wear on the reverse-drive side of the track bushings and sprocket teeth. The only time bushings rotate against sprocket teeth under load is during reverse operation. During reverse operation, approximately 75 percent of pins and bushings are under contact, load, and motion, from the bottom of the front idler to the first pin and bushing joint engaged by the sprocket tooth. Make reverse travel productive. Forward operation puts about 25 percent of the pin and bushing joints under contact, load, and motion.
KOMTRAX is Komatu’s remote equipment monitoring and management system that records data from the machine during operation. KOMFAX is the report that is produced from this data, which is then used to determine the working condition of the Komatsu Machine.