Heavy equipment machinery

April 21, 2007

Will bulldozers make it better?

Filed under: Bulldozers

Blame the people, blame the politicians, blame the buildings. Elizabeth Farrelly wonders if architectural change offers any hope for Redfern.

Redfern hits the headlines again. So in-yer-face and still so secret, Redfern’s the Block - in stark contrast with Bondi’s The Block - sits at the burnt-out end of the glamour spectrum, regarded by most of us, sight unseen, as scary and squalid. And while the kind of determinism that Band-Aids architectural solutions onto social problems is long discredited, recent events can only exacerbate calls for demolition.

At first glance this might seem like a good and reasonable thing, completing from within what the "natural" forces of lifestyle redevelopment and government sanitisation have begun from without. But, although the Block’s traditional terrace-house stock has hindered improvement efforts, outright obliteration of this cultural landscape would be a profound cultural loss for Sydney.

Redfern, in sickness and in health, has been the centre of urban Aboriginal culture in Australia for generations - a crossroads, literal and metaphorical. Like a node in Rover Thomas’s Roads Cross, the Block (bounded by Hugo, Young, Eveleigh and Caroline streets) is that to which all paths eventually lead. For white culture too, though, Redfern has been a nodal point, the crossing of mainline rail and two major roads (Regent and Cleveland). It’s an inner-city six-ways, albeit one we might rather ignore. And crossing - between cultures as well as thoroughfares - is at the core of Redfern’s dilemma, as well as its history.

Aboriginal Redfern exists because of jobs offered by the Eveleigh yards in the 1930s, and the cheap housing nearby. The architect Col James recently received the Institute of Architects’ President’s Award for 30 years of honorary work with the Aboriginal Housing Company (AHC) that owns the Block. "Country people," he says, "would arrive looking for roots, gravitate to Redfern, become [say] fettlers, find work in the goods yards."

Since then, there have been waves of creative energy, intercut with waves of dereliction. The bad old ’70s days of riot police and street strife were followed by self-help redevelopment euphoria in the ’80s - its successes and failures - then full-on heroin culture in the ’90s. It is this, the drug stranglehold, that recently impelled the AHC to demolish most of the houses on the Block, resulting in relocation of all but four of the 15 known drug houses.

Nevertheless, now must be one of Redfern’s ebb points. It’s alive, but hardly vigorous, while upscale land-uses clamour at the gates. Current descriptions dust-off old terminology - slum, eyesore, squalor - guaranteed to nurture the reactive "comprehensive-redevelopment" impulse.

Which is exactly what the so-called RED (Redfern-Eveleigh-Darlington-Waterloo) strategy promises.

RED, a supposedly all-encompassing, all-of-government project, inspires in this consultation-fatigued community as much mistrust as optimism; not least because of the secrecy-cloaked-as-consultation that surrounds it. The Premier’s Department won’t talk, not on record, and local member Clover Moore has repeatedly queried RED’s real agenda, in and out of Parliament. Bob Carr’s reply? "The Government’s approach is to go to the market with a plan to seek comprehensive redevelopment that takes account of the need for social renewal of the area as well as other matters."

That’s planning. Ask the market. They closed the local primary school because RED’s population dropped beneath 20,000 (from more than 50,000 in the 1920s), not seeing that the market had taken Redfern into its own hands. All around - along Broadway, on the old Carlton United site, and at Green Square - upscale residential has sprouted in vast quantities, morphing daggy old South Sydney into the designer-res hinterland of a newly global city.

Even in Redfern, the council’s shiny new community centre is nearly finished, while virtually everything outside the Block has been invisibly mended into Newtown, Chippendale, Darlington or Strawberry Hills. Council plans to revamp the roller-shuttered high street may or may not survive the merger, but at North Eveleigh’s Wilson Street carriageworks site, the Government quietly commissioned from Tonkin Zulaikha Greer a $35 million performance space and approved its masterplan for a residential and cultural redevelopment, up to 12 storeys with 600 units and 8000 square metres of offices.

Even the public housing along Elizabeth-Phillip streets is up for redevelopment. There’s talk of rehabilitating Redfern Oval, next to Redfern Park (where Keating made his famous "we committed the murders" speech of 1992) and across from the Rabbitohs to public access, and "serious" consideration to sending a mini-tunnel under the Regent-Gibson street intersection, healing one of Sydney’s worst pedestrian-hating crossings.

Transport is the key, and the incentive. RED studies show Redfern could provide 20,000 jobs within 400 metres of the station while the Australian Technology Park (ATP) masterplan allows its floorspace to quadruple, employing 6500 people at Eveleigh and several hundred more at Eveleigh North. Redfern has the infrastructure; trains, buses, parks. Plus the Parramatta-Chatswood line, if and when, makes Redfern an essential bead on the so-called "think-link", joining five universities (Macquarie, UWS, Sydney, UTS - all three campuses - and UNSW) with the Royal North Shore and Westmead teaching hospitals, as well as the bio-med and high-tech facilities at the ATP.

Central to it all, of course, is Redfern station, or what’s left of it. Proposals involve a total revamp: fringing the heritage station with street-friendly retail, flanking it with 12-storey residential towers (so you’d scarcely notice Nati Stoliar’s $25 million TNT twins, one lately occupied by South Sydney Council), bridging over the tracks and reorienting the lot towards the street.

All this may be inevitable; certainly it’s a trend any new super-council will intensify. But within it all, Redfern-the-Block is pincered. Redfern station, capacity-rich, is barely used; it serves seven of Sydney’s 10 lines but is only ninth-busiest in the network. Town Hall Station, meanwhile, is full, grubby and virtually unexpandable. Redfern, next along, is close, breezy and convenient, but no one gets off there because, even with a permanent police presence, that reputation, that fear-factor, outweigh all else.

Ten years hence, if the Premier’s Department and the 45 government "partners" in its RED Strategy have their way, Redfern as we know-it will be no more. Question: is this a good thing?

Sure, there’s graffiti. There are troubled and un-tame people. There are goomies (the old name for metho drinkers) and gatherings and even bonfires on the street, night and day. It is intimidating; no doubt about it. The sense of territory around the Block is palpable. Nothing is defined, not a word said. And yet the demarcation is clear. Partly, this is genuine threat; part is the invisible membrane with which marginal communities surround themselves. But is erasure the answer? Or are we simply intimidated by difference, and by Redfern’s active dissent from our oh-so aspirational culture?

This has to be understood since, if Redfern is to survive, it will need to withstand not just the sanitising urge sweeping our town but also societies’ instinct to destroy the object of fear.

So, consider. It is possible to see Redfern differently. To see it as core cultural fabric, enriching the entire city; to see its very difference rendering it not less but more important, the closer we come to glossed-out globalism. It is possible to see that the Block itself, as a made urban landscape, has its own beauty, a beauty which we owe it to ourselves to see. Hang the graffiti and the paint-patched walls in a gallery, they’d be instant art. Valuable, even. So, what can be done?

Quite a lot, probably. No one would suggest that Redfern’s problem is primarily architectural, but many agree that getting rid of the London-type terraces would help. Not only are they dark and depressingly internalised, but their yards and lanes are so secluded they seem designed for the drug-deal. Even half-demolished, Eveleigh Lane is known as "million-dollar lane" for its annual turnover; Caroline Lane, where the needle bus (until recently) dropped its daily load, is a shooting alley so deep in needles the fire brigade comes to sluice it out. Occasionally. Plus, says Col James, if the local kids want in to a house they simply scoop a hole in the century-old lime mortar and sandstock, and walk through the wall.

Is there a better model? If so, what? And how, after all the well-meant failures, will we know? Can house-design cross cultural boundaries? How real are such boundaries, anyway? And how can you design for a largely itinerant population without a clear paradigm for urban Aboriginality?

The architect Dillon Kombumerri, now with the Government Architect’s Merrima group, is collaborating with the AHC on its Pemulwuy rebuilding project. Kombumerri, with family ties in Redfern, worked with the AHC in the ’80s "when Charlie [Perkins] was still around". He believes the first step is to abandon preconceptions about what is "culturally appropriate" and design "as any good designer would", from first principles and an open mind.

There are important differences, of course, from "ordinary" Australian housing. These include, says James, the need for bigger houses (allowing seven or eight per house) with at least half the floor area outside and duplicate facilities to allow cooking, eating, sleeping and even bathing to happen under the stars. "That’s the beauty and the wonder of the place that you can interact spontaneously and in a large, social way," Kombumerri says.

And where white culture (with the possible exception of those in the Horizon) stresses privacy, early Pemulwuy sketches show all balconies, gardens and streets subject to communal supervision. Another key concept is to open Red Square, opposite the station and always the ignition-point of Redfern’s troubles, to competition, redesigning this gauntlet of intimidation as a large and welcoming public place.

There’s also a desire for symbolism. One proposal, drawn from Mandawuy Yunupingu’s 1993 Boyer Lecture, is ceremonially to replace the "poisoned waterhole" of the old Railway View Hotel, corner Lawson and Eveleigh, with a billabong, doubling as a functional retention basin to reduce flooding on Vine Street. The mingling of salt and fresh water would symbolise the black-white cultural mix, but also the constant renewal of Redfern’s heartland with fresh rural blood.

James recognises that the Block, like an overstressed adolescent, has suffered periods of self-harm. But he remains stubbornly optimistic: "I think we’re doing better than we’ve done in the past. We’ll make mistakes, but we’ll learn from them. I think we’ll get a lot of it right. Aboriginal people like comfort, just like anyone else."

To many, of course, white as well as black, being truly Aboriginal means living bush. Even in Redfern, says Kombumerri, with its deeply urban history, "there is a hard core of traditionalists who would like to have a bush setting. But it’s not sustainable - for example with hygiene. You’d need a much bigger paddock."

As to the question of an urban paradigm. "I think it’s there," says Kombumerri. "People just need to get it in their heads that just because they’re in the city, it doesn’t mean they’re not black. They just need some pride in themselves and in their culture." That’s the ask. It may not work, but it has to be more promising than a kneejerk engagement in Dispossession II.

Doze More Dirt

Filed under: Bulldozers

Challenge conventional thinking and reevaluate your production dozing. Making every move count calls for working back to front.

Steep hourly cost makes operating efficiently more important to crawler dozers than most other construction equipment. The cost is largely associated with undercarriage wear, so the best dozer operators make every move count whether they’re doing production earthmoving, finishing or clearing land.

Some of the best ideas for improving dozer productivity defy operators’ assumptions.

"A lot of operators who are doing production dozing think they should make long cuts. They want to see dirt boil or roll in front of the blade," says Brad Van De Veer, senior product consultant at Caterpillar’s Edwards Demonstration/Application Center. "In reality, the blade will only hold so much dirt. Once it’s full, you start losing dirt off both sides of the blade, leaving windrows that will have to be moved again. It wastes horsepower and fuel, and it can cause track slip and undercarriage wear.

"You should be able to get a full load on the blade in two lengths of the tractor at the most — and that applies to any size tractor. Once the blade is full, you stop cutting and slide the dirt in front of the blade."

Short, aggressive cuts set up what is perhaps the most energy-saving way to doze dirt — what Caterpillar calls "front-to-back or slot dozing."

"You start one to two tractor lengths back from where you’re going to move the dirt, instead of on the opposite side of the field," says Van De Veer. "Fill the blade and start a pile or fill the area."

The next step is to back up one to two tractor lengths behind the start of the first cut, fill the blade, and slide the load, or carry it, through the slot created by the first pass and deposit it on the spoil pile. Use first gear to aggressively fill the blade. In small and medium sized tractors, shift up to second when sliding the load. Repeat the process, sliding a full blade load through the slot further with each pass.

Working in the slot increases blade load by as much as 30 percent and prevents material from falling from the blade.

Front-to-back dozing cuts undercarriage costs. Instead of backing the entire length of the cut after each push, you only reverse the tractor the distance of the previous push plus one or two tractor lengths.

"Running in reverse causes the most undercarriage wear, and it’s the most unproductive time in the work cycle," says Van De Veer. "Working front to back, you reduce the amount of reverse operation, which decreases operating costs and increases productivity."

Van De Veer says slots can be dug as deep as the blade is high.

After the first slot is completed, back up to about two tractor lengths from the spoil and move over, leaving about one-third of a blade width between the edge of the blade and the first slot. This berm will hold material in front of the blade on the second slot.

After the slots are cut to the desired grade, the work pattern reverses for clearing the berms.

"You want to work from the rear of the cut, or the opposite end from the spoil, rather than front to back," says Van De Veer. "Load up the blade quickly, and use blade tilt to steer into one of the slots to carry the load to the pile or fill."

A criss-cross pattern will help keep the cut level: If you slide the load up the left slot on the first pass, swing into the right slot on the second pass, and then back to the left slot on the third.

Some simple techniques will make fine grading more efficient, too.

A videotape called Tips From the Pros: Crawler Dozer from VISTA Start Smart Training recommends: "When finishing or dressing, working with a partially loaded blade is better than working with an empty one. It smoothes out the ride and distributes fines across the blade.

Load only half of the blade to keep windrows on one side of the machine. The blade can overlap previous passes to act as a depth guide.

"The smoothest finishing jobs happen when dirt is worked from at least two different directions [passes oriented at 45- to 90-degree angles to each other]," according to VISTA. "It’s the same principle as an orbital sander on wood. Irregularities get smoothed out if attacked from more than one direction."

Van De Veer adds a special reminder to stay alert when finishing.

"When you’re finish dozing, you usually have grade checkers or other laborers on the ground, you’re working in a confined area with grade stakes, and maybe curb and gutter or drain tile. You can get pretty focused on the blade and the job in front of you, but you have to pay attention behind when backing up."

A crawler dozer’s basic design makes the machine a prime candidate for working where other machines fear to tread. They’re not immune to danger, though.

"Low center of gravity and power in the tracks make crawler dozers excel in slope work — working in areas that other machines can’t or shouldn’t touch," says VISTA’s Tips videotape. "But know your machine’s limits. Rollovers are a leading cause of injuries and fatalities."

Caterpillar’s equipment-training program for crawler dozers admonishes operators to work more slowly on slopes, keep attachments low, and work up and down slopes if possible.

"Don’t think you can jump clear of a tumbling machine," warns VISTA. "Always wear your safety belt and make sure the ROPS is in good condition.

"When pushing dirt off a high wall or a steep slope, don’t push each load over the edge," the Tips video recommends. "Leave one blade load at the edge to act as a stop. Let the second blade-full push the first one over the edge. This keeps your machine back away from danger."

When you’re working down a slope, remember that gravity can be your friend.

"Pile several loads at the brink of the hill, then push them down the hill in one pass," VISTA recommends. "You’ll be able to move more material.

"Keep the machine under control at all times. Many newer machines have hydrostatic transmissions with automatic holdback. But on machines with torque converters, never coast downhill in neutral, and don’t change gears while going downhill. Save the wild rides for the amusement park."

Van De Veer reminds slope workers to check machine manuals for recommended adjustments to oil levels. Working on certain inclines, a sump that’s not properly filled can leave the oil-intake high and dry and the engine starved for lubricant.

Clearing trees is another potentially dangerous job for which crawler dozers are remarkably suited. Make sure the dozer’s falling-object protective structure (FOPS) is in good condition.

Look for a tree’s natural direction of lean. It will be the best direction to push the tree. Adjust the direction of fall to avoid obstacles. Check the tree for dead branches that could fall.

Sever roots with a series of V cuts. VISTA recommends leaving the roots on the intended direction of fall untouched. They should act as a hinge, controlling the tree on its way to the ground.

Push the tree over with the center of the cutting edge, raising it high to improve leverage.

"When the tree starts to fall, reverse the dozer quickly to avoid the rising root mass," says VISTA’s Tips video.

Large stumps can be uprooted in similar fashion. Although with no risk of a tree falling on the machine, you can V cut roots all around the stump for easier removal.

One key that operators hold to improving crawler-dozer efficiency has nothing to do with operating technique. It’s maintaining track-chain tension, and it can reduce undercarriage wear by 50 percent. Caterpillar field surveys have found 20 percent of tracks too tight.

Operators are crucial to long undercarriage life because chain tension can require more-than-daily maintenance. Chain tension is judged by measuring sag — the amount that the track hangs down between the sprocket and the idler, or the idler and carrier roller. Operator’s manuals include the recommended amount of track sag, and describe how to adjust chain tension.

There is no regular interval for checking chain tension. When mud starts packing in the sprockets — whether it rains, or the tractor hits a wet layer of earth, or the haul trucks start dumping wet spoil in the fill — someone has to stop and adjust chain tension.

Conditions may change again before the day’s out — the spoil starts coming dry, or the tractor moves to higher ground, or the sun heats up and the wind starts to blow. To keep the loose chain from binding in front of the idler, the tension must be adjusted again.


http://www.buyerzone.com/industrial/bulldozers/rbic-doze-more-dirt.html

Human shields or bulldozers? Or neither?

Filed under: Bulldozers

Nine months ago, Israel’s Supreme Court forbade the Israeli Army to use civilians as human shields when it raided houses to arrest Palestinian combatants. Last week, the Israeli newspaper Haaretz reported that the consequence of the ruling has actually been to place Palestinian civilians in greater danger. Instead of soldiers entering houses to find their targets, the army is using bulldozers to knock the houses down.

 
The army of a democracy fighting an insurgency - Israel in the West Bank, like the United States in Iraq - faces tough choices. Its government requires it to observe rules of war intended to protect the rights and lives of civilians. At the same time, commanders must protect their soldiers. The two imperatives often conflict.
 
When I served as an Israeli infantry reservist in the West Bank in the 1980s and ’90s, sometimes my company would be sent to apprehend a terrorist. Under the direction of an agent from the Israeli counterterrorism agency, Shin Bet, we’d surround and then raid the house where the man was believed to be hiding.
 
We usually had a Palestinian to help us. He was called "the pointer," because his job was to enter the house with us and identify the man we were after. He was a collaborator - a Palestinian serving the Israeli cause.
 
Most of my friends hated going on these raids. We’d surround the house and break in after midnight, waking everyone inside. Women would scream, children cry. As often as not, the man we were after had been tipped off and fled. If he was there, it was worse, because he’d be armed and dangerous.
 
The pointer made some of us feel safer. It seemed logical that the terrorist would hold his fire if he saw that he might hit a Palestinian.
 
We used Palestinian civilians for other tasks as well. If we discovered that the boys in the village had jury-rigged a roadblock during the night, we’d grab some nearby civilians and order them to dismantle it. This was partly an act of collective punishment, but there was also a safety factor. If the roadblock was booby-trapped, they’d get hurt instead of us.
 
I always felt queasy about using civilians to protect us. It didn’t seem to me that we had the right to put someone else’s life in danger to protect our own. I voiced my reservations on occasion, but nothing changed.
 
Sometime during the years that followed, the pointer and roadblock clearers evolved into something even more questionable: the human shield. Soldiers who had to raid a house or patrol a dangerous stretch of road would grab a nearby civilian and place him in front of them.
 
The routine became much more widespread in April 2002, when Israel reoccupied the West Bank in response to a wave of Palestinian suicide bombings and other acts of violence against Israeli civilians.
 
In August of that year, a Palestinian man, Nidal Abu Mohsen, was killed while serving as a human shield. Israeli human rights organizations filed suit to halt the practice, and last October, the Supreme Court handed down its ruling banning its use.
 
Many in the army were upset. They felt they had been robbed of a tool which helped the commanders protect the lives of their soldiers.
 
But morality in combat is not just an abstract principle. It is an element of an army’s strength. It is also essential to the society that sends the army into battle. If the safety of soldiers becomes the standard according to which an army designs its missions, the army will not have the courage to take risks. So it’s not unreasonable - in fact, it’s essential - for a society to demand that its army observe moral standards, even if the price to be paid is that more soldiers are killed.
 
But sometimes eliminating one morally questionable practice opens the door to others. Once the Israeli Army banned the use of human shields, it had to come up with another way of extracting the Palestinian guerrillas from their hideouts. Hence the bulldozer. Of course, this method is much more dangerous for the family inside.
 
Israel can’t stop hunting down its enemies. Can it do so without bulldozing houses that harbor terrorists? Certainly it can. Raiding a house is a dangerous operation, but good intelligence, proper planning and careful execution can, in most cases, reduce the risk to a reasonable level.
 
In some cases, the risk may be too great and the operation may be canceled or postponed until the next opportunity comes around.
 
Laws and moral rules are another set of constraints. In a purely military sense, armies could better do their jobs if they could ignore the civilians on the battlefield. But we don’t allow them to ignore civilians. And truth be told, I’ve never met a soldier who thinks armies ought to be able to maim and kill civilians with impunity.
 
Getting rid of the bulldozer may well mean that some terrorists will get away, and sadly, that more soldiers will die. But in the final analysis, Israel and its soldiers will not be less secure. They will occupy the high ground, and that is the most secure place to be.

http://www.iht.com/articles/2006/06/21/news/edwatz.php

What is a Bulldozer?

Filed under: Bulldozers

A bulldozer is a heavy piece of earthmoving equipment which uses a front-mounted ‘dozer’ blade to push soil forward and create a level surface for construction sites. A modern bulldozer consists of a tracked chassis, protective driver cage, rear-mounted ripper claw and a variety of front-mounted blades. Some militaries add armor plating to a standard bulldozer for even more protection and deconstruction power.

The earliest bulldozer models were little more than farming tractors equipped with straight front-mounted plates for rough landscaping and plowing. Earthmoving equipment manufacturers such as Case, Terex and International Harvester refined the basic design, curving the front blade for improved cutting power through hardened topsoil. Another modification was the addition of a rear-mounted ‘ripper claw’ for breaking up boulders and sections of roadway materials. Some bulldozer blades can also slice through trees or double as front-end loader buckets.

There are several theories concerning the origin of the word bulldozer. Technically, the word only applies to the front dozer blade, not the entire machine. Some sources suggest that the power and noise of the chassis suggested a restrained bull, while others point to the extreme medical practice of bull-dosing. What began as a term for a strong dosing of medicine became slang for intimidating tactic. Whatever the original etymology, there is no doubt that a bulldozer can be a very intimidating sight when placed outside a condemned structure.

The most common place to find a bulldozer is a new construction site. The operator may use the rear-mounted ripper claw to break up rocks, pavement or hardened ground. The next step is to set the front-mounted blade at a prescribed depth and literally push the loosened soil forward. Tracks similar to those used on military tanks allow the bulldozer to remain stable on sandy or muddy soil. Eventually the entire site should be level enough for construction to begin. A bulldozer is not usually involved in the more subtle aspects of site preparation, but occasionally it may be used for rough deconstruction or as an auxiliary front-end loader.

The world’s militaries also depend heavily on modified bulldozers for battlefield engineering projects and a form of local ‘gunship diplomacy.’ Perhaps the most famous military bulldozer is the Case D9, used primarily by the Israeli army for decades. The driver’s compartment is protected by bullet-resistant glass, while the rest of the machine is heavily armor-plated. When the front blade is raised to the level of the driver’s compartment, the Case D9 can drive through most obstacles unscathed.

http://www.wisegeek.com/what-is-a-bulldozer.htm

Bulldozers

Filed under: Bulldozers

Powerful crawler equipment with a blade is called a bulldozer. Even though any heavy engineering vehicle is known by the term "bulldozer", practically the term refers only to a tractor with dozer blade.

Earlier tractors were used to plough the fields and the first bulldozer was adapted from this tractor. During the First World War a bulldozer was used as an armoured tank because of its versatility in grounds which were soft.

A big thick metal plate is fixed on the front of the bulldozers for use in earthmoving jobs, raising dams and digging canals. As the tractor advances, the blade in front removes layers of soil. To move coal in the coalmines, to move large boulders or cut tree stumps, various specialized blades are used. Earlier, the driver used to sit on top of the bulldozers, which lacked a cabin. When powered down bulldozers were introduced in the 1930’s it became the excavation equipment preferred by contractors. Find more info at http://www.just-bulldozers.info

When equipment was needed to execute large-scale earth works, several bigger models were manufactured by various engineering firms. These machines were noisy, large and powerful and that’s where it got its name "bulldozer".

More powerful engines, better tracks, more reliable drive tracks, raised cabins and instead of the usual cable operations, hydraulic arms were some of the important improvements included in the bulldozer development.

More precise blade manipulation was made possible by hydraulic systems. To loosen soils which were rocky, or for pavement bread-up, a ripper claw was also added to bulldozers.

Throughout the world, these durable and tough machines are used by construction units of the military, they are also the preferred equipment for civil construction. Some of the other uses of bulldozers include demolition of enemy structures and clearing mines.

The tracks on the bulldozers give good hold on ground and easy mobility over rough terrain. In order to prevent it sinking in muddy or sandy ground, the wide tracks help the distribution of the weight of the bulldozer over large area. The torque divider in the bulldozer converts its power into ability to drag.

The power of the bulldozer can be gauged by its ability to tow tanks weighing around seventy tons. Areas of obstacles such as shrubbery, and burnt vehicles can be cleared easily.

Over time, bulldozers have been further modified to become a new machine capable of working in various ways which was not possible with the original bulldozer, for instance a hydraulic arm and a large bucket, which can be raised or lowered to scoop earth and load it into trucks.

http://www.articlesbase.com/autos-articles/bulldozers-59282.html

Declaration Regarding Caterpillar Violations of Human Rights

Filed under: Bulldozers

Declaration Regarding Caterpillar Violations of Human Rights

WHEREAS

The Caterpillar Corporation’s machinery is directly implicated in grave abuses of human rights and humanitarian law by the Israeli army;

The Israeli army has used Caterpillar equipment to uproot hundreds of thousands of olive trees as well as orchards of dates, prunes, lemons and oranges, causing widespread economic hardship and environmental degradation in rural areas of Palestine;

Since 1967, the Israeli army has used Caterpillar equipment, including specially modified D9 and D10 bulldozers to destroy over 12,000 houses in the West Bank, Gaza Strip and East Jerusalem, leaving tens of thousands of men, women and children homeless;

Since September 2000, the Israeli army has used Caterpillar equipment to destroy more than 3,000 homes, hundreds of public buildings and private commercial properties and vast areas of agricultural land;

Home demolitions are usually carried out without warning, often at night, and the occupants are forcibly evicted with no time to salvage their belongings. Often the only warning is the rumbling of the Israeli army’s US-made Caterpillar bulldozers beginning to tear down the walls of their homes;

The Israeli army has continued bulldozing homes even when notified that residents were still inside the targeted homes;

Dozens of Palestinians have been killed in such instances, such as Nabila al-Shu’bi, who was seven-months pregnant, as well as her three young children and four additional members of her family, left to die under the rubble of their Nablus home when it was bulldozed on April 6, 2002;

On March 16 2003, 23-year-old American peace activist Rachel Corrie was murdered by Israeli soldiers driving a Caterpillar D-9 bulldozer, while she was standing in non-violent protest of a home demolition in Rafah;

All these home demolitions and civilian deaths are illegal under international law, specifically violating the Hague Regulation of 1907 and the Fourth Geneva Convention;

The Israeli army uses Caterpillar bulldozers to build a separation wall with significant portions of it inside the Occupied Palestinian Territory;

The International Court of Justice considered the construction of such a wall to be contrary to international law-specifically violating the Hague Regulation of 1907; the Fourth Geneva Convention; the International Covenant on Civil and Political Rights; the International Covenant on Economic, Social, and Cultural Rights; and the Convention on the Rights of the Child;

The sale of Caterpillar bulldozers to the Israeli army is carried through the U.S. Foreign Military Sales Program and is in violation of the U.S. Arms Export Control Act, U.S. Public Law 90-829, which prohibits the use of U.S. weapons against civilians and for anything outside of "internal security" or "legitimate self-defense";

The sale of the Caterpillar bulldozer to the Israeli army contravenes the United Nations’ Norms on the Responsibilities of Transnational Corporations and Other Business Enterprises with Regard to Human Rights, which stipulate that transnational corporations "shall not engage in nor benefit" from war crimes or other violations of human rights and humanitarian law (article C3); and that transnational corporations "shall refrain from actions which obstruct or impede" the realization of basic human rights, such as the right to development, adequate food and drinking water, adequate housing, and the highest attainable standard of physical and mental health (articles E11 and E12);

Caterpillar’s involvement in the above-described abuses has attracted the attention of the United Nations and leading human rights organizations;

The Office of the UN High Commissioner on Human Rights has written to Caterpillar CEO James Owens that "allowing the delivery of your. . . bulldozers to the Israeli army. . . in the certain knowledge that they are being used for such action, might involve complicity or acceptance on the part of your company to actual and potential violations of human rights…";

Amnesty International has issued a call to Caterpillar to "take measures - within the company sphere of influence - to guarantee that its bulldozers are not used to commit human rights violations, including the destruction of homes, land and other properties";

Human Rights Watch has called on Caterpillar to suspend the sale of its D9 bulldozers, parts or maintenance service to the Israeli army, so long as the military continues to use the bulldozers to violate international human rights and humanitarian law;

The Presbyterian Church (USA) General Assembly voted July 2, 2004 to start a process of a phased and selective divestment of its nearly eight billion dollar portfolio from select companies that profit from sales of products or services that cause harm to Palestinians or Israelis or both. The Presbyterian Church (USA) researchers are working to determine which companies profit most "from building settlements, from constructing the wall and from selling machinery that destroys Palestinian homes, vineyards and orchards." The case of Caterpillar is currently being considered by the group’s Mission Responsibility Through Investment (MRTI) Committee;

The Israeli Committee Against House Demolitions supports divestment from companies that profit from involvement in the Occupation, including Caterpillar whose bulldozers demolish thousands of Palestinian homes;

All of the facts described above are a matter of public knowledge;

The sale of the Caterpillar bulldozer to the Israeli army contradicts Caterpillar’s own Code of Worldwide Business Conduct, which states that "Caterpillar accepts the responsibilities of global citizenship" and recognizes that Caterpillar’s "commitment to financial success must also take into account social, economic, political, and environmental priorities";

Spokespeople for Caterpillar, Inc. have acknowledged that Caterpillar is aware of the Israeli army’s use of Caterpillar equipment to destroy civilian homes, infrastructure and agricultural resources but Caterpillar has, nevertheless, refused either to condemn these practices or to take actions necessary to halt the sale or transfer of Caterpillar equipment to the Israeli army;

THEREFORE

We call on Caterpillar to stop selling bulldozers to Israel until Israel stops using these machines to destroy Palestinian lives and livelihoods in contravention of human rights and humanitarian law;

We call on Caterpillar to establish transparent and credible mechanisms for independent monitoring and verification, with the assistance of human rights ngos, to establish when these conditions are met;

We further call on Caterpillar to adopt a code of conduct which complies with the UN Human Rights Norms for Business and ensures the application of Article 11, which states that Trans National Corporations and other business enterprises should take stringent measures to prevent any products or services they produce or supply from being used to commit violations of international human rights or humanitarian law.

We further call on civil and human rights activists, faith-based organizations, peace activists, Arab-American organizations, Jewish groups, students, and others who promote peace and justice in Israel and Palestine to join us in our efforts.

http://www.catdestroyshomes.org/article.php?id=242

Emergence Of The Multipurpose Dozer

Filed under: Bulldozers
Caterpillar D6

Advances in drivetrains and controls enable the Komatsu D65 mid-size dozers to be used in a variety of applications, including fine grading.

The John Deere 850 transmits power to the ground through an efficient hydrostatic transmission.

In between the 400–hp pure production dozers and the under 100–hp finish models lies the mid–size dozers. The role of these units continues to evolve with advances in controls and drivetrain technology.

“These dozers have not traditionally been used for fine grading,” says Brett Errthum, John Deere. “But more contractors today are finding they can be used for fine grading.”

This is driving a trend toward extended track models. “Customers are asking for better grading capability,” notes Errthum. “The easiest way for us to do that is to put a longer track on it.”

Speed And Fine Grading Critical

Rodman Excavating, Frisco, TX, relies on mid–size dozers for fine grading. The company owns 45 dozers, including 31 185–hp John Deere 850s, a few John Deere 750s, plus five Caterpillar D8s, four D9s and one D10. “We really don’t have a use for the small fine–grade dozers,” says Les Foster, senior vice president — operations.

The John Deere 850s are popular with Rodman Excavating due to the hydrostatic transmission, which is unique in this dozer size class. The hydrostatic transmission matches Rodman’s applications — cutting swales and fine grading building pads. “It cuts them very quickly. Then we can fine grade the pad very quickly,” says Foster.

These dozers are equipped with six–way blades and wide shoes for low ground pressure. “We are fine grading a lot of pads and if it is a little wet, we don’t want to sink in,” says Foster.

When confronted with very tight spaces, Rodman Excavating will rent smaller dozers. However, Paul Herron, fleet manager, points out, “Ninety–eight percent of the jobs can be completed just with the John Deere 850.”

Operators have a lot of input into which dozers they run. “They are the ones out there every day. They have to be comfortable and be able to put that machine to use,” says Herron.

A Versatile Solution

Another contractor using medium–size dozers for a variety of applications is Robinson Paving Co., a Georgia–based firm with an equipment fleet numbering over 200 pieces. “We do a fair amount of grading,” says Darrell Robinson, general superintendent. “I have a couple of jobs right now that each have about 900,000 cu. yds.”

Robinson Paving uses four Caterpillar 621 wheel scrapers and eight Noble 417 pull–type scrapers pulled in tandem by 9000 Series John Deere four–wheel–drive and Caterpillar Challenger tractors.

Its dozer fleet is almost entirely Caterpillar D6 machines. “I don’t think this company will ever move away from a Caterpillar D6 because it is such a dependable machine,” says Robinson. “It has just done such a good service for us.” Yet, the company recently purchased a 190–hp Komatsu D65EX extended track model to supplement its fleet.

Due to the nature of its business, the dozers in Robinson’s fleet need to be versatile to handle multiple tasks. The contractor’s current project provides a good example. “On this particular project, we are running four 30–ton Volvo [articulated trucks] in the same grading operation with the Noble pans,” Robinson explains. “A lot of times, we will put the Komatsu D65EX in the fill area to push the piles from the articulated trucks.”

This machine floats around as needed. For example, Robinson has a Caterpillar D6M slope machine with a wide track. Because there is more slope work on the current project than one machine can handle, the D65EX also gets pressed into a little slope work. “It does well there,” says Robinson.

But the primary task of the D65EX has been in the cut.

The material on this project is mostly clay, but it can quickly turn to sand. “You just run into a band of sand. A lot of times this will be a pretty good–sized area,” says Robinson. “With the pull pans, you will not get quite full pulling through the sand.” The D65EX is used to help push the scrapers. “You get good, heaped loads out of it, especially when we are in just a short cut,” he states.

Robinson Paving has been happy with the addition of the D65EX to its fleet. “It is such a versatile machine,” says Robinson. “It is a good size that you can put in heavy work or light work. It is good for finish work, cutting ditches, cutting slopes and pushing. It is just a good all–around machine.”

Comfort is an important issue for Robinson. “I like to hear what an operator says about a machine,” he says. “If they like to run it, they can do a better job.

“The hydrostatic steering system has been so much easier for the operators to run,” he adds. “They are more productive with it. I have a guy on it that has been running dozers all of his life. He likes being on it. The controls are just operator friendly. That can really make a big difference with the production and the quality of the work.”

Robinson is also excited about a Caterpillar D6R purchased in October 2003. This tractor is equipped with the Rotating Bushing Track, which should help in the abrasive sand. “I think that is going to be one of the big benefits for the Caterpillar D6. It could cut your costs way down. You don’t have the downtime, and there are costs of pulling the tracks and sending them in to have pins and bushings turned,” he states.

The Rotating Bushing Track is designed to increase chain life when operating in sandy or abrasive conditions. “With the rotating bushing track, you do not get relative motion between the sprocket and the bushing,” says Kent Lynch, sales engineer for track–type tractors, Caterpillar.

However, as with any track configuration, there are limitations. “It is not recommended in high–impact conditions,” says Lynch. “When you get into conditions that might twist the undercarriage, it is probably not as solid as a standard chain.” Unless it is used in sandy or abrasive environments, you may also be unable to justify the cost premium.

Control Advances

“The biggest change has been toward electrohydraulic or electronic controls for steering and transmission, as well as implement control,” says Ronald Schultz, commercial manager, Caterpillar. “The electrohydraulic/electronic controls currently use smaller movements and less force.

Through on–line interactive adjustment, they can provide varying response rates to meet the needs of different applications or operators.”

While the ability to tailor the “feel” of controls to the individual operator is a relatively simple task on Caterpillar dozers, the company is about to release another leap forward. Lynch claims the dozers will soon be equipped with a small 4x5 screen. “You will have the specific settings on that screen by operator name. You just call up a name, hit a button and the machine will set itself to those preferences,” he explains.

Another emerging technology is the onboard diagnostic panel. “From the smallest Komatsu dozer to the largest, all will feature onboard diagnostics,” says Ed Warner, product manager — dozers, Komatsu. “No longer does the technician have to come out with a set of gauges or a laptop computer. It’s all done through the onboard diagnostic panel.”

Other benefits to the onboard monitor are the ability to accurately track forward and reverse travel distance for track maintenance and as a supervisor tool, as well as the ability to track and schedule preventive maintenance, such as oil changes.

Operating parameters can also be controlled through the monitor. “If you want to lock out third speed reverse, we can do that,” says Warner.

Some manufacturers are also striving to standardize controls across the entire size range so operators can more easily jump from one machine to the next. For example, Errthum reports that John Deere has standardized controls across its dozer product line.

Komatsu has taken a similar approach with the Palm Command Control System on its dozer line. “Now an operator can get off any of the Komatsu dozers, jump to another model and he is right at home,” says Warner. “There is no change.”

The Correct Choice

All manufacturers stress the importance of comfort when choosing a dozer. “Select the dozer that is going to keep the operator happy,” advises Warner. “Make sure the operator is comfortable and the machine has good ergonomics.

Look at the visibility. Take 180º and note what you can see with the tractor. Look at maintenance. Those items that are going to give you a good cost per hour give you the competitive edge when you are bidding on a job.”

Finally, make sure the tractor is spec’d to provide optimum performance on your particular jobsites. The combination of track lengths, gauges and shoe widths complicate dozer selection. “For a Caterpillar D6R, you are probably talking 15 to 20 different configurations,” says Lynch. “So it gets rather complex. I don’t think customers always know how many options are out there.”

These choices allow an optimum solution for almost any task. “There are so many different applications, the biggest asset any of these companies has is to work with their dealer,” says Lynch. “They are the ones that really understand what goes on in a particular geographic territory and what other customers are doing in similar types of work.”

——————————————————————————————————–

Hydrostatic vs. Torque Converter Drive

Dozers under 100 hp typically feature hydrostatic drive. This allows the tractor to maneuver more quickly in finish grading applications. “The hydrostatic transmission is beneficial in a utility application where maneuverability is required,” says Ronald Schultz, Caterpillar. But there is disagreement regarding the efficiency of hydrostatic transmissions in mid–size dozers.

Most mid–size dozers use powershift transmissions with torque converters. “With technology currently available, the best hydrostatic transmission is 5% to 15% less efficient than a powershift transmission with torque converter drive,” claims Schultz. “In cases where dozing performance is of key importance, a mechanical transmission will generate a higher percentage of engine power transmitted to the blade or ripper, given that both machines are well balanced.”

Schultz asserts that powershift transmissions can also tackle finish grading. “A powershift transmission, when backed by a differential steering system, can give the level of maneuverability to larger tractors when finish dozing is a required part of the owner’s needs,” he explains. There is also a trend toward electrohydraulic controls that simplify operation. “All of our machines are moving in that direction.”

Komatsu America also equips its mid–size and larger dozers with powershift transmissions with torque converters. They are coupled with the Komatsu Hydrostatic Steering System for ease of maneuverability, according to Ed Warner. “A torque converter allows you to have that ‘umph’ you need when you initially need to load the blade or if you are digging a stump. You just don’t get that with the hydrostatic transmission,” he claims.

However, Brett Errthum argues that hydrostatic transmissions in the mid–size John Deere dozers are just as efficient as torque converter drives, plus they simplify operation. “In the past, hydrostatic dozers had limitations,” says Errthum.

“We have a long–term relationship with our component supplier to develop pumps and motors specifically for our application. Really, the breakthrough came in better electronic controls that help divert the power to where it is necessary.

We have been able to overcome what has been the traditional downfall of the hydrostatic transmission on a large dozer.”

John Deere dozers use a load–sensing hydrostatic system. “When they sense that a load is bogging the tractor down, they will actually slow down the hydrostatics,” says Errthum. “By slowing it down, you are going to get more pushing power.” There is no need for the operator to shift the transmission to compensate for the load. “With a powershift transmission, you generally have three speeds,” he continues. “We have an infinite range.

It will just vary infinitely to the point that it needs to carry the load through. The operator doesn’t do anything that whole time. All he does is focus on that load in front of the blade, making sure his blade is positioned well as he carries the dirt forward.”


http://www.forconstructionpros.com/print/Equipment-Today/Features/Emergence-Of-The-Multipurpose-Dozer/5FCP203

Environment Drives Dozer Design

Filed under: Bulldozers

The environment affects crawler-dozer choices in two distinctive ways in today’s market. First, jobsite conditions determine size, undercarriage and blade choices. Second, and more pertinent to the current state of the machine category, regulations handed down by the Environmental Protection Agency have introduced advances in electronics, which have changed machine control and production.

Dozers move material, and those conditions and applications drive the choices in machine size, undercarriage and blade. Power-angle-tilt blades, also known as PAT, with 6- or even 7-way maneuverability are becoming popular in larger dozers. Smaller dozers, less than 100 horsepower, tend to be used to finish grade, and their bigger siblings rely on brute power to move large quantities of material from place to place.

According to Construction Equipment’s 2002 Universe Study, 43 percent of crawler dozers are less than 100 horsepower. Primary life of a dozer averages 11 years, and scrappage occurs at about 19 years. In 2002, the average age of crawler dozers in the machine universe was 8.6 years. And equipment managers have stretched machine life and productivity during the recent economic downturn.

Manufacturers are fielding machines now that take advantage of EPA-engine-emissions mandates to introduce more electronic controls and operating benefits. Add to that the reliability of machine-control systems and today’s crawler dozers offer managers much-improved choices.

As manufacturers have implemented engine electronics, they’ve been able   to provide the plumbing for additional features such as auto shift. "When you can tell that engine that you’re in the process of shifting, and it can momentarily make the shift then bring the engine on task, you have the best of both worlds," says Warren Groth, track-type tractor product support engineer for Caterpillar. "You can extend the life of components and give the operator smooth and comfortable changes." Caterpillar, Komatsu, John Deere and Case have implemented electronic hydrostatic drives, which enable the machine to match the pumps that drive the individual tracks, giving the operator better turning control. "Electronics allow you to absorb full power of the engine so the inside track can slow down," says Rob Warden, Komatsu’s product manager, dozers.

Most manufacturers—except Deere—keep hydrostatic transmissions to the smaller machines, usually cutting off at 100 horsepower. Larger machines typically require higher levels of torque in order to move loads, and the standard there is still direct-drive powershift transmissions.

The other technological boon for dozers is in machine-control systems, specifically blade control. Laser- and satellite-based systems have reached such levels of acceptance and accuracy that end-users report substantial savings in costs and improvements in productivity.

These successes include some applications that hadn’t been accurate with staking, such as fine-finish grading. Although motor graders aren’t in danger of being replaced, properly equipped dozers can do the fine-finish work in some applications, such as house pads.

"You can go from dirt to finish with a crawler with blade control," says A. John Holmes, John Deere’s product sales consultant for crawlers. "Mainly, you reduce transportation and maintenance [of the grader], and you reduce the number of operators."

Caterpillar and Komatsu have teamed up with specific suppliers to offer grade-control systems: Caterpillar with Trimble and Komatsu with Topcon. Komatsu is in the "infancy of the alliance," says Warden. Caterpillar has formed a joint venture with Trimble, called Caterpillar Trimble Control Technologies. This company supplies components to both Cat and Trimble. Caterpillar has designed its AccuGrade Laser Grade Control System and is factory-installing it on the D3, D4 and D5 G-Series track-type tractors.

Both manufacturers say the reason they partner with one supplier is to make it easier to install such systems on their machines. "We wanted to fully integrate a blade-control system into our machine," says Caterpillar’s Groth. "The best way was to go with a selected company so we could best integrate their product and our tractor."

Cat customers who use different grade-control suppliers will have to rework the machine, Groth concedes, but it will still take less time to install because the hydraulics and electronics have already been made ready.

Other dozer manufacturers try to make their machines control-ready, as well, leaving the vendor choice fully in the end-user’s hands. Deere, for example, manufactures its GPS-ready dozers with open power connections in the fuse block and well-protected hydraulic control valves.

Average Crawler-Dozer Costs Size Range List Price Hourly Cost*
*Monthly ownership cost (based on list price) plus operating expenses, divided by 176 hours.
Source: EquipmentWatch.com, 800/669-3282
105–129 hp $144,857 $53
130–159 hp $187,354 $75
160–189 hp $229,477 $89


100-hp Crawler-Dozer Competitors Manufacturer Model Operating weight (lb.) Net horsepower Dozer blade type Blade cap. (cu. yd.)
About 43 percent of the crawler dozers in operation are less than 100 horsepower. In this comparison of the 100-hp category, we’ve lined up the low-ground-pressure versions, all of which have PAT blades.
 

http://www.constructionequipment.com/article/CA457524.html

Spec Master: Crawler dozers

Filed under: Bulldozers


Length with blade in straight position, without ripper(feet, inches) [position 1]
If the blade is further out away from the machine, you gain some visibility but lose operator response. If the blade is placed closer to the machine, you have quicker operator response but lose some visibility. The total length of the machine also becomes a factor when transporting medium dozers.

Track length on ground(feet, inches)
[position 2

The more track on the ground (fore or aft), the less machine pitch and greater stability. Longer tracks give you a more stable platform and are good for light dozing and finish grading. The additional track length, however, also adds more weight and makes the machine slightly less maneuverable.

Height to top of cab(feet, inches)
[position 3]

Also a transportation issue, especially with medium dozers, which tend to move from job to job and need to clear bridges and other overhead obstacles.

Ground clearance(inches)
[position 4]

This comes into play especially in forestry and pioneering work, where working around stumps and uneven ground is an issue. Another application where this becomes a factor is soft underfoot conditions. The more ground clearance you have, the better chance you have of not getting stuck. This needs to be balanced by machine designers, however, with center of gravity.

Track gauge(inches)
[position 5]

Track gauge is measured from the mid-point width of one track to the mid-point width of the other track. A wider gauge typically gives you better machine performance when working on slopes.

Operating weight with dozer blade and
without ripper(pounds)

Make sure you know which dozer blade is being figured into this since blades can vary in weight. The weight and balance of the machine are critical. Typically more weight and horsepower is required when you need to push heavy loads in a mass production situation. Balancing the front of the machine with either a counterweight or ripper comes more into play when finish dozing.

Net horsepower
Horsepower is usually more critical in heavy dozing, when you’re looking for high productivity. With finish dozing, it becomes a factor in steering. A dozer should have a good horsepower-to-weight ratio. If you have too much horsepower and not enough weight, you’ll spin the tracks, lose productivity and waste undercarriage life. When there’s not enough horsepower and too much weight, the machine will struggle to stay up with productivity demands.

Transmission and drive
Transmission type

Power-shift transmissions have generally taken the lead over mechanical transmissions in heavy dozers, although mechanicals are still used. Power shifts offer less operator fatigue since operators shift with buttons instead of levers. Smaller dozers feature hydrostatic transmissions, which give you infinitely variable speeds and greater maneuverability. Hydrostatic transmissions, however, are more susceptible to contamination, keeping them out of heavier dozers. Torque-divider transmissions are more efficient than torque-converter types, but they also take up more space and are more expensive. Both torque-divider and torque-converter transmissions are seen on heavier machines.

Steering system type
Most present-day clutch-brake systems are electric over hydraulic, allowing finger-tip control in large tractors instead of the old lever-pedal controls. Clutch-brake systems allow you to pivot turn by locking up one track and turning on the other track. Differential steer systems are a bit more costly, but you gain the ability to power turn and counter rotate since there’s power to both tracks. Dual-path hydrostatic transmissions are used primarily on smaller machines, and give you the ability to pivot turn, counter rotate and maneuver in tight spaces.

Gear speeds, forward and reverse
If the machine has a power-shift or mechanical transmission, it has three forward and three reverse speeds. Hydrostatic transmissions have infinitely variable speeds. While using third gear for long periods of time is discouraged because it accelerates undercarriage wear, this may be less of a concern in the future as undercarriage designs and materials advance.

Maximum travel speed
Be sure you balance the speed and gear selection in your dozer operations to the undercarriage wear. Because of their infinitely variable speeds, hydrostatic transmissions have more flexibility in this area than power-shift or mechanical transmissions.

Undercarriage
Track shoe widths available (inches)

As a general rule, try to use the narrowest shoe with which you can maintain flotation. Be aware that wider tracks start adding weight and tend to make the machine less maneuverable. Wider tracks are recommended, however, for jobs that have soft underfoot conditions or slope work. Some users run narrow track shoes with wide-gauge tracks, thinking it gives them better stability in finish grade work. Be careful of running wider shoes in rocky conditions since the track pads incur more stress.

Standard track shoe width(inches)
Standard track shoes will suffice for the majority of applications. Each type of undercarriage – extra long, extra wide or low ground pressure – will typically have their own standard shoe size, although all can be customized. The width of the dozer blade can also affect the width of the track desired.

Ground pressure(psi)
This is a factor of the weight of the machine, length of track on the ground and the width of the track pad. Wider tracks and more track on the ground lessens ground pressure.

Blade
Blade type

There are a number of blade options, all designed to address the needs of specific dozer applications. These include U blades, which are shaped to retain the material as you load, allowing you to move large volumes of material. Carry dozer blades add even more volume, but lose some penetration ability and so are better for loose material. Semi-U blades are suited for utility dozing and have a great deal of flexibility in changing ground conditions. Straight blades have limited applications because material retention is less. Power angle tilt, or PAT, blades are flexible and useful in finish grading and a variety of other applications.

Blade width(feet, inches)
This becomes a concern on smaller dozers if you want to be able to move the machine on a truck without taking the blade off. When you get into medium-size dozers, you’ll usually be required to take the blade off the machine in order to transport it.

Blade height(inches)
This dimension is critical for large tractors since you don’t want any material coming over the blade and getting into the radiator or the front of the tractor. Height also becomes a blade weight factor and must be balanced with the weight of the tractor. Blades are typically shorter on smaller dozers because visibility is so important.

Blade capacity(cubic yards)
This will vary depending on the type of blade used, but is usually listed in specification tables as the capacity of the standard blade. Consider the productivity you require on a job when selecting both the tractor size and the type of blade to match with the dozer.

Blade dig depth(inches)
This is a key factor, especially if you are doing a lot of finish grade utility work with smaller tractors.

Maximum blade tilt, hydraulic(inches)
The amount of blade tilt is limited by the track since you don’t want the blade push arms to touch the track. Dual-tilt tractors offer more blade tilt on both sides than does a single-tilt tractor. With a single-tilt tractor, there’s more tilt on one side than the other. Blade tilt is more important on medium-size tractors while blade pitch is generally more important on larger machines.

Ripper
Ripper depth, multi-shank (inches)

For medium-size dozers, a multi-shank ripper with curved teeth is usually used since you’re not trying to pry out large obstacles or rocks. This type of ripper loosens the top material so you can doze it.

Ripper weight with one shank(pounds)
The weight of the ripper many times serves as a counterweight on machines carrying a heavy blade. Parallelogram single-shank rippers are needed for rock or hard conditions. Depending on the application, there are shanks that can go as much as 15 feet deep working behind a large tractor.

http://www.equipmentworld.com/apps/news/articleeqw.asp?id=48058

Product Focus: Compact dozers

Filed under: Bulldozers

Dislodge stumps, clear land with D75, D85 and D95 dozers
The New Holland D75, D85 and D95 deliver blade angle forces up to 31,000 pounds and blade angle torque up to 85,200 foot-pounds. This allows these machines to dislodge tree stumps, clear land and do finish grading, ditching, backfilling or spreading. Rated at 75, 84 and 96 horsepower respectively, the dozers’ turbocharged engines have an integral water pump and oil cooler and a poly V-belt with automatic belt tensioning. The machines feature hydrostatic transmissions that provide smooth, precise steering control and speed changes from 0 to 6 mph. The transmission automatically adjusts dozer speed and torque to match changing load conditions. The counter-rotating track allows you to make 180-degree spot turns for fast direction changes and easier maneuvering in tight spaces.


Adjust the blade cutting edge angle with a quick wrench turn
The 450J, 550J and 650J John Deere dozers offer standard, infinitely adjustable blade pitch link. With only one wrench, the blade cutting edge angle can be adjusted to any position from 52 to 60 degrees. The J Series machines use Deere PowerTech 4045T engines with 500-hour oil change intervals. The engine’s wet-sleeve cylinder provides quiet operation, improved cooling and simplified design. The machines’ dual path hydrostatic drive transmission has infinite speed control, a power management system, live power turns, counter-rotation, dynamic breaking and automatic tracking control. A Speed-in-Grip transmission control system offers an increased number of user definable rates, allowing flexibility in tailoring the operating characteristics of the machine to your preferences.


PowerStat muscles full blades through curves and turns
Case Construction Equipment’s 650K, 750K and 850K Series 2 dozers have quiet, high-visibility cabs, hydrostatic PowerStat drive for maximum power throughout a turn and a tilting operator’s station for easy servicing. The PowerStat drive gives the machines extra muscle, and Case-designed PowerStat components for the high horsepower needed to push the fullest blades, even through curves and turns. This reduces the number of passes needed to move material. The hydrostatic drive is controlled by a single lever with electronic straight tracking, two bump-up, bump-down speed buttons with six speed increments and an adjustable ratio of reverse to forward speed.


Upgrade small machines with laser grade control system
Caterpillar’s G-Series small dozers – the D3G, D4G and D5G – produce 70, 80 and 90 horsepower at the flywheel, respectively. Standard equipment includes two heavy-duty, 12-volt 900 CCA batteries, a turbine-type precleaner, a 110-amp alternator for longer life, and an air intake heater for easier cold-weather starting and an adjustable suspension seat. The machines can be upgraded with the Caterpillar AccuGrade Laser Grade Control system as a factory-installed feature that allows you to fine grade with increased accuracy.


Tailor your speed to the job at hand
Komatsu America’s line of KomStat II dozers – the D31EX/PX-21, D37EX/PX-21 and D39EX/PX-21 – feature the company’s electronic control hydrostatic transmission and Palm Command Control System for advanced operator control. The hydrostatic transmission allows variable (20 increments of speed adjustment) or intermediate (three distinct speed ranges) speed selection. Both variable and intermediate modes allow you to match the dozing speed to jobsite conditions. The dozers also have adjustable reverse speed control, allowing the machine to reverse either slower or faster than the chosen forward dozing speed.

http://www.equipmentworld.com/apps/news/articleeqw.asp?id=56442

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