January 2009: Cover Story

Unearthed Excavator Mysteries

Japan, 1930 — a mysterious new machine rolled out of Kobelco Construction Mfg. Co.’s manufacturing plant. Churning steel tracks carried the 50K electric mining shovel, casting a shadow that would be similar to future mechanical diggers. Three decades later, hydraulic excavators populated jobsites, turning monumental excavating projects into afternoon projects.

While excavators — with more than 15 manufacturers in the North American market alone — are a common sight on nearly any jobsite, developing technologies have altered the landscape of excavator offerings. New systems such as telemetrics and automatic grading, improved hydraulics, attachments and beyond led to new, efficient excavator operations. Utility Contractor investigated and — thanks to an anonymous tip and the brightest minds in excavator manufacturing — uncovered productive excavator solutions.

Digging up the Facts
Finding the Evidence for Renting Excavators
By Roger Johnson

One of the toughest questions a contractor has to ask is whether to buy or rent equipment. But the answer is no mystery. There are five very compelling reasons the excavator rental market is enjoying increased growth, and they all benefit the contractor who is renting and using the equipment. There are no capital or maintenance costs involved. The transaction is 100 percent deductible. There are no down-time expenditures. Today’s economic climate makes long-term rental usage both possible and desirable, and some companies actually offer rent-to-own programs.

Safe equipment operation is the first priority, so have your rental center experts guide you through correct control procedures on their property.

Today’s high-quality compact excavators rated less than 16,000 lbs operating weight are reliable and well suited for a wide range of applications. This versatility makes them popular pieces of equipment for contractors and utility professionals alike. And because of their smaller size, they are less intimidating to use confidently and effectively. Still, there are several logical steps any potential excavator renter must undertake to make this project as safe and productive as possible.

First, determine if the unit you’re considering can physically access the intended worksite. Is there a gate to pass through? Are there steep or uneven work surfaces? How wide is the unit you’ll be renting? How heavy is it? How deep must you dig? How deep can you dig? Are there underground power or gas lines nearby? (Call your local One-Call number or the Common Ground Alliance phone number (811) that covers all states.) How far will the bucket reach? How high must you reach to dump the bucket? Will you be working close to a wall or in a confined area? To do a professional job use professional techniques like taking notes and measurements and following that guidance to the letter.

Towing the Load

Transporting the machine to and from the jobsite is also a critical consideration. Most rental businesses, according to Nick Grittani, Regional Sales Manager for Yanmar Construction Equipment, require that a renter have a legal trailer that is the right size for the excavator being considered. Many rental centers will also have trailers available for rental. Naturally, the tow vehicle must also be legal, safe and right for the job. Remember, you’ll be exposed to as much liability transporting the excavator on public roads as you will be simply using it on the jobsite. Safety first, so seat belts should be utilized even during the loading and unloading process.

For a mini excavator, you’ll need a tow vehicle with at least a 13,000-lb gross vehicle weight rating (GVWR) — the total number of pounds the vehicle can haul — and a 12,000-lb GVWR-rated trailer. That should cover mini excavators that fall within the 3- to 4-ton class excavators — the most popular size for excavator rentals.

Some centers even provide a pickup and delivery service. If you intend to transport the machine yourself, find a source with business hours that are compatible with your particular schedule. After all, no one wants to be responsible for such an expensive machine sitting in an open field over the weekend with the meter running. It’s also wise to have access to a service department and their technicians during the job in the event of unforeseeable complications.

Learn from the Experts

Today’s better service centers offer instruction in basic equipment operation that also includes the use of any required attachments. Fortunately, most of today’s compact excavators offer simple controls and smooth hydraulic boom swing and digging motions, as opposed to the machines of the past.

Safe equipment operation is the first priority, so have your rental center experts guide you through correct control procedures on their property. This is especially true if the excavator in question is a newer model you with which you might not be familiar. This is also the time and place to practice with any attachments that might be required for your job.

For a first-time operator, it is essential to learn the controls and feel comfortable operating the machine’s varied functions. Start with the seat belt and make sure the unit is on level ground and stable before beginning any operation no matter how small. Lowering the blade firmly on the ground will help stabilize the machine. Like a big league slugger, practice a few swings of the arm and become comfortable with the way it raises and lowers. The same goes for curling the bucket. Now, gradually combine the motions slowly and smoothly. Don’t be in a hurry — smooth and steady is the name of this game.

Care and Feeding of the Excavator

Determine what the daily routine of component inspection should be before you turn on the machine for the day’s work. Have an employee of the rental company guide you through this procedure if you’re uncertain. Have that same employee give you a complete walk-around on the machine. Don’t take anything for granted. Inspect the tracks, quick-coupler and boom stress points; scan any irregularities, fractures or excessive wear. It is also a good idea to quiz the dealer about the machine’s maintenance schedule such as when the oil was last changed (typically done every 500 hours).

Most mini excavators sport rubber tracks so look at the tension to ensure a snug fit and make sure there aren’t any deep gouges or tears in the rubber. Check that all fluid levels (oil, coolant and hydraulic) are where they should be. It helps if you have the dealer show you all these check points before taking the machine home. When the machine lands on the jobsite, you’ll want to do another visual inspection of all components before putting it to work.

Finally, Grittani recommends you look for a compact excavator that offers true zero tail swing clearance. Most damage occurs when the new operator forgets that pesky overhang that some non-zero tail swing machines have. And speaking of clearance, keep plenty of it between you and everything.

Remember, as a rule people love to watch this kind of equipment in action. You always have to watch out for someone trying to get a closer look. For best results, just add good sense.

Roger Johnson is a Technical Writer for Pratt & Buehl, based in Atlanta.

Dial “A” for Attachments
Calling Upon the Perfect Blend of Equipment and Implements
By Amber Reed

Means and motive are always at the top of an investigator’s list when solving mysteries. In gathering the facts of the jobsite, the most efficient way for a contractor to approach a job is often the question. Motivated by a tight schedule, a contractor often uses multiple attachments on one machine as the implements of production.

With a variety of attachments to use, excavators excel at utility site tasks like: craning utilities into place overhead or burying underground; digging, compacting and backfilling trenches; breaking up concrete; and digging postholes. Public and private companies put excavators to good use when it comes to installing or repairing utility lines — any project requiring deep-digging capabilities and heavy-craning abilities.

According to Lance Schjenken, Terex ASV Attachment Marketing Specialist, manufacturers offer a variety of attachment options for excavators to increase the versatility of the machine. Standard excavator attachment offerings include various buckets, compaction wheels, hydraulic thumbs, rippers, couplers, vibratory plate compactors, hydraulic hammers (or breakers) and augers.

No matter what attachment an operator is using, the key to productivity is to make sure the machine’s hydraulic flow is matched to the attachment.

The next generation of attachment offerings will include various grapples for material-handling. Many excavators, like Terex models, also come equipped with a short dozer blade on the front of the unit for dozing, grading and finishing tasks.

“Attachments increase an excavator’s productivity on utility projects,” says Schjenken. “For example, tilting or ditching the bucket allows operators to perform grading and finishing work in areas where a traditional dozer can’t access or on sites where it doesn’t make sense to have an extra piece of equipment.

“Tilting is done with a grading bucket and can also be used for digging when the excavator is not operating on a level surface,” says Schjenken. “With a hydraulic thumb attachment, excavators can easily lift, move and place rocks and stones during site preparation and clean up when working around existing landscapes.”

No matter what attachment an operator is using, says Schjenken, the key to productivity is to make sure the machine’s hydraulic flow is matched to the attachment, and that it is easy for operators to change out and operate the attachment. For instance, quick-coupler systems make it fast and easy to change attachments. And auxiliary hydraulics offer flexibility in adding attachments.

An Inspection a Day Keeps the Mechanic Away

“Like an excavator’s daily maintenance routine,” says Schjenken, “attachments need daily care and inspection to maximize an owner’s investment.” Three simple steps will keep attachments working for a long time.

Step 1: Check for any leaks or cracks in the attachment’s hoses and fittings and make sure the fittings are not loose. Also, check that the hoses and fittings are clean and free of contaminants.

Step 2: Make sure all of the attachment’s critical points are lubricated and functioning properly. Schjenken recommends washing down the attachment after use to remove jobsite contaminants that accumulate during operation. Once the attachment is clean, lubricate according to the manufacturer’s guidelines.

If the attachment and/or the attachment system are hydraulically operated, says Schjenken, routine maintenance on the hydraulic system is critical. Follow both the excavator manufacturer’s and the attachment manufacturer’s service recommendations for these checks.

Step 3: Inspect your excavator’s attachment system to make sure the locking mechanism is operating properly. Complete a daily walk-around of the excavator to spot wear and tear, including a check of the attachment as well. This is especially important if the attachment stays on the machine in long-term applications. “Attachments have wear points too,” says Schjenken. “For example, on buckets the edges and teeth will wear over time. These wear points must be fixed or replaced as needed because good edges and teeth increase productivity.”

In the end, excavators with a host of attachments are ideal for utility work where other machines wouldn’t be as productive.

Amber Reed is a Technical Writer for Performance Marketing, based in West Des Moines, Iowa.

Climbing the Tech Tree
New Technology Is Charged with Being Clean and Efficient
Compiled by UC Staff

As time ticks by, technology continues to progress. The once elusive Tier 4 engine standards are just around the corner, causing engine OEMs and machine manufacturers alike to retool their machines to make them more efficient.

Before delving into the evidence of improvements, let’s look at the facts. Emission regulations — called Tier standards — were created by the Environmental Protection Agency (EPA) more than a decade ago for both off- and on-highway diesel engines; each sector has similar standards and deadlines. For the construction industry, off-highway diesel engine Tiers are coming to a head as the final and most stringent set of regulations (called Tier 4) are already here for small diesel engines. The 25- to 74-hp engines hit Interim Tier 4 in 2008 and the Final Tier 4 standards for all horsepower ranges are fast approaching in 2013 through 2015.

“To date, the recent technologies associated with the Tier 3 standards have resulted primarily in the improved fuel efficiency of excavators,” says Mitch Blake, Brand Marketing Manager for Case Construction Equipment. “The Case excavators, for instance, have seen as much as a 20 percent increase in fuel efficiency depending on the model, which is directly related to Tier 3 technology. As we move to the Tier 4 standards, look to see a further improvement in fuel efficiencies than is experienced today in excavators.”

With fleet management systems like Komatsu’s Komtrax, you can see where your excavator worked, when your excavator worked, how much fuel it used and beyond to streamline your operations — making them more efficient.

At this time, the primary metrics associated with productivity are fuel consumption and cycle times. All other metrics are appendages to these pillars of productivity. Other factors such as weight of the material, engine work modes and idle times are also effective metrics to track since they have an effect on the productivity of the machine.

“Technologies surrounding more effective and efficient ways to power an excavator and provide function to its operations will be the crux of the technologies we will see in the short- to mid-term future,” says Blake. “During this time, the use of GPS and on-board utility locators will increase. Long-term, we will see remote and automated operation of excavators.”

Take load-sensing hydraulic systems, like those found on Kubota excavators. Load sensing hydraulic systems aim to improve responses to operator input, cycle times and productivity, while reducing operator fatigue. Load sensing systems deliver the power only where and when necessary based on the stroke of the lever. More power and flow directed only when and where needed increases speed and productivity, all the while conserving fuel. The auto-idle system reduces fuel and oil consumption and reduces sound levels and emissions.

While making sure that equipment is properly and efficiently utilized, there are a few less obvious benefits of knowing where your machines are and what they are doing. The first is time card comparisons. With telemetric systems like Komtrax from Komatsu, you’ll know the exact hours a piece of machinery worked — its digging and load/carry cycle times, engine idle and machine shutdown. At times, machine operators work long, laborious hours and toward the end of the week, it can be difficult to break those hours down. If there is ever a discrepancy of hours worked, the fleet management system has tracked and logged it — revealing the hidden working methods of excavators.

Blades of Steel
Mike Boyle, John Deere’s Product Consultant for Excavators, Breaks Down Excavator Backfill Blade Wielding

The best method of backfilling in most operations is a combination of excavator bucket and backfill blade. If room is available, an operator can pull more material back into a trench with the bucket than with backfill blade, but it is a lot faster to finish with the backfill blade than the bucket. And there are as many different backfilling techniques as there are trenches:

The backfill blade can be used in the front of the machine for extra stability when lifting heavy loads. When lifting with the blade down, the fulcrum point is at the end of the blade instead of the idlers.

Backfilling a deep trench — Push material back into the trench at a 90-degree angle or perpendicular to trench. The 90 -degree angle will keep material from caving into trench, and if it does cave in, the operator can back the excavator away from trench. It’s a good idea to always leave extra spoil material on center of trench to track it down on the final pass.

Backfilling a normal trench — Push the material at 45-degree angle toward the trench. The operator can push enough material in each pass to fill trench. The last passes should be parallel to trench to pack the material and fill in the voids. At a 45-degree angle, the operator should always fill trench before running on fresh backfilled material.

Backfilling a swallow trench — Windrow material into trench. On the first pass the operator should run parallel to the trench and bump material into trench. The second and third pass should fill the trench and finish the grade.

Backfilling a manhole — The operator should work the material around the manhole evenly, starting at 90 degrees on first couple of passes. If manhole is deep, the operator may have to push material to each side. He or she will then reset the excavator’s material push-in at perpendicular passes.

Backfilling a rocky material — A combination of blade and bucket may work best. The operator can handle the large rocks with the bucket and place them into the trench without scratching up the blade.
Beyond backfilling, the blade can be used in a multitude of productive ways:

1. The backfill blade can be used to increase reach digging depth. When operators are trenching and trying to reach the extra or deeper than boom, arm and bucket allows, they can put the blade behind the machine and lower the blade, which raises the back or the excavator. The front of the excavator naturally goes lower, so the geometry of the boom is lower and the excavator can reach further.

For most operations, if room is available, an operator can pull more material back into a trench with the bucket than with backfill blade, but it is a lot faster to finish with the backfill blade than the bucket.

2. The backfill blade can be used in the front of the machine for extra stability when lifting heavy loads. For example, when lifting a manhole with the blade down, the fulcrum point is at the end of the blade instead of the idlers.

3. The backfill blade can be used for reach. If the operator is loading a truck and can’t reach over the side boards of the truck, he can lower the blade, which raises the front of the machine for a higher dump height.

4. The backfill blade can be used to carry pipe or hold a pipe from swinging by pinning the load against the blade to prevent the load from moving.

5. When climbing onto a trailer, the operator can lift the machine up with the boom so that the blade is on the trailer. He or she can then swing around and lift the opposite end of the machine up and push with the boom and arm as the blade slides on the deck of the trailer. When the tracks are on the trailer, the operator lifts the blade as he drives on holding the machine stead with the boom and arm from the opposite side.

6. The blade can also be used to hold the machine from sliding. When digging hard soil, handling slippery material or working on frozen ground, the operator can push the blade into the soil and hold the machine even if he or she has to dig crevices for a slot to hold the blade.

7. Blade lift eyes can be use to tie excavator down to trailer. On the corners of the blade there are usually lift eyes or tie down loops use for chains or slings to hold machine on trailer.

8. A backfill blade can be used to help load the bucket. With large rocks or landscape material, the operator can force the material in or onto the bucket by pinning it against the blade.