Heavy Equipment Operation

Excavators, dozers, loaders and backhoes move the earth that every other trade builds on. A skilled operator can trim a trench bottom to a fraction of an inch with a machine that weighs as much as a loaded truck. That same machine can crush a coworker in its blind spot, roll on a slope, or hit a power line. Smooth, careful operating is the job.

You cannot learn to run a machine by reading. Plan on hands-on training with a qualified operator, and follow the manual for each machine. OSHA requires employers to allow only trained workers on equipment. Crane operators need certification or a qualification under 29 CFR 1926 Subpart CC, and some states and unions add their own licenses.

What You Will Be Able to Do

• Match a machine to a job and explain its main limits.
• Run a full walk-around and start-up check.
• Know how excavator control patterns differ and how to confirm one.
• Describe digging, grading and truck-loading techniques.
• Protect workers on foot, the machine and yourself on any site.

Machines and What They Do

Excavators

The upper structure, or house, rotates on a swing bearing. The swing radius is the arc swept by the counterweight as the house rotates, and it reaches past the tracks. Anyone inside that arc can be pinned against a wall, truck or stockpile.

Dozers

A ripper on the back breaks up rock, frozen ground and heavily compacted material so the blade can move it.

Loaders and Backhoes

A wheel loader steers by bending at a center hinge, called articulated steering. The rear end swings wide in the opposite direction from the turn, which can catch anyone standing beside the machine.

A backhoe loader has stabilizer legs (outriggers) that must go down before you dig. They steady the machine and resist the reaction forces from the arm.

Skid Steers and Compact Track Loaders

A compact track loader (CTL) is a skid steer on tracks. Its main advantage is better traction and flotation on soft ground, because it spreads the weight over a bigger area.

Ground Bearing Pressure

Ground bearing pressure is the machine's weight divided by the area in contact with the ground. It tells you whether soft ground, a slab or a trench edge can hold it.

Worked example. A 50,000-pound excavator has two tracks, each 24 inches wide with 150 inches on the ground.

• Contact area = 2 x 24 x 150 = 7,200 square inches.
• Pressure = 50,000 / 7,200 = about 7 psi.

That is why a wide track floats on ground that would sink a wheeled machine of the same weight. Soft fill, buried tanks, old basements and trench edges all fail under loads they seem able to carry.

Controls

Excavator Patterns

Excavators use two joysticks, and there are two patterns. Mixing them up can swing a bucket into something.

ISO is the most common pattern in North America and the default on most excavators. The backhoe pattern is the one on many backhoe loaders, and some older machines use it. Many machines have a selector, so always check the setting and test each function slowly before digging.

Travel: Two levers or pedals drive the tracks. The drive sprockets are normally at the rear. When the house is turned 180 degrees from straight ahead, the travel controls are reversed. Pushing forward moves the machine toward you, not away. Look down at the tracks to find the sprockets before you travel.

Dozers and Loaders

Dozers use a joystick or levers for steering and blade control, plus a ripper control if fitted.

On a wheel loader, the shuttle lever (or pedal) selects forward or reverse. A joystick controls the boom and bucket. Kickout settings stop the boom at a preset height and return the bucket to a preset angle, so each pass is the same.

The Daily Walk-Around

Before starting any machine, do a walk-around. Take 10 to 15 minutes. Look around the machine, under it, and on top of it. Record what you find.

Fluids

• Engine oil. Check it on level ground, normally with the engine cold, since that gives the most reliable reading. Follow the manual if it differs.
• Hydraulic oil. Read the sight glass or dipstick. If it is low, top it up but find out why before operating. Fluid goes somewhere.
• Coolant. Read the overflow tank. Never open a hot radiator cap, because boiling coolant and steam can erupt and burn you.
• Fuel and DEF. Diesel exhaust fluid (DEF) is a urea solution used on Tier 4 engines to reduce emissions through selective catalytic reduction (SCR). If it runs out, the engine will lose power.

Undercarriage and Tires

• Tracks. Common sag is about 1 to 2 inches at the midpoint between the idler and first roller. Check the manual for how your machine is measured. Too tight wears parts fast, and too loose can throw a track.
• Rocks and mud. Clear packed rocks out of the undercarriage. They damage rollers, idlers, sprockets and seals.
• Rollers, idlers, sprockets. Look for leaks, cracks and heavy wear.
• Tires. Check pressure, cuts and lug nuts.

Hydraulics

Look for leaks at cylinders, hoses and fittings.

Warning: A pinhole hydraulic leak can inject oil through your skin. It may look like a small puncture, but it is a surgical emergency. Never use your hand to check for leaks. Use cardboard. If oil gets into your skin, go to an emergency room right away.

If a hose starts leaking while you work, shut down immediately and tag the machine out for repair.

Safety Systems

• Seat belt and ROPS (rollover protective structure). The ROPS only protects you if you stay inside it, so wear the belt every time.
• Backup alarm, horn, lights, mirrors and cameras.
• Fire extinguisher.
• Handrails and steps. Clear off mud and ice.

Start-Up

Warm up the machine as the manual says. Cycle each function slowly through its full range, then test brakes and steering, and look at the gauges.

Read the hour meter each day. Maintenance intervals such as oil and filter changes go by machine hours, so this is how you know when service is due.

Getting On and Off

Use three points of contact, facing the machine. Never jump down. It is a short drop onto uneven ground, and it causes ankle, knee and back injuries. Keep your hands free of tools when you climb.

Digging and Moving Material

Trenching

1. Confirm the utilities are located and that the dig plan is in place. Dig by hand near marks.
2. Set up on firm ground, in line with the trench.
3. Dig toward the machine. Curl the teeth in, pull the stick toward you, and adjust the boom to hold grade.
4. Set the bucket down gently, and do not use it as a hammer.
5. Place spoil at least 2 feet from the trench edge.
6. Check grade often. It is easier to take off a little more than to put it back.

No one enters a trench 5 feet or deeper without a protective system, unless it is all stable rock.

Lifting With an Excavator

Excavators can lift loads if they are rated for it. Use the machine's load chart and rigging points, never a tooth or a chain around the bucket. If the machine begins to tip, lower the load to the ground immediately. Do not try to swing it away.

Loading Trucks

1. Put the truck where the swing is short.
2. Swing the bucket over the rear or side of the truck bed, never over the cab.
3. Spread the load evenly, starting at the front of the bed.
4. Dump close to the bed floor, so that rocks do not slam down.
5. Signal the driver when loading is complete.

Dozing

• Push material from high spots to low spots, using downhill slopes when you can.
• Keep the blade low on any downhill move, carried close to the ground. It stabilizes the machine and can act as a brake.
• Slot dozing, which means working between two low ridges of material, keeps more in front of the blade.
• For finish grading, use light cuts of 1 to 2 inches, overlapping your passes. Check against stakes, a laser or GPS.

Wheel Loader V-Pattern

1. Approach the pile with the bucket flat and low.
2. Drive in, raise the boom slightly, and curl the bucket back.
3. Back out in a turn toward the truck, then approach it to form a V.
4. Dump centered in the bed, then back away and return.

Keep loads low when you travel. A raised load makes the machine top-heavy, and rough ground can turn it over.

Slopes

Travel straight up and down when possible, not across. Follow the machine's slope limit in the manual. Keep attachments low. Avoid turning on a slope, and do not leave the machine on one without chocks and the brake set.

Protecting Workers on Foot

• Set the swing zone. Barricade the swing radius of the counterweight.
• Make eye contact. No one approaches a machine until the operator has seen them, signaled and stopped.
• Use a spotter near workers, trenches or obstacles. If a spotter signals stop, stop all machine movement immediately. Any person on site can give a stop signal.
• Listen to the backup alarm. It warns workers on foot that the machine is backing up. Where a machine's rear view is blocked, OSHA requires either a working alarm or a signal person.
• Know your blind spots. Each machine has them. Cameras and radar help, but look too.

Power Lines

The main danger near overhead lines is that the machine or boom contacts them, and everyone touching it can be electrocuted. Under OSHA rules:

• Keep at least 10 feet from lines up to 50 kilovolts, and more for higher voltages.
• Treat every line as energized until the utility says otherwise.
• Use an observer when it is hard to judge distance.
• Cranes have stricter rules, with a 20-foot default until the voltage is known.

If you do make contact, stay in the cab and warn others to stay away. If fire forces you out, jump clear with your feet together, and shuffle away without lifting your feet.

Cranes and Load Moment Indicators

On a crane, a load moment indicator (LMI) warns the operator when the load is approaching the crane's tipping capacity. It does not replace load charts or a qualified lift plan.

Shutdown and Parking

1. Park on firm, level ground, clear of traffic and excavations.
2. Lower all attachments to the ground. OSHA requires blades, buckets and dump bodies to be fully lowered or blocked when idle or under repair.
3. Put controls in neutral, set the brake and shut off the engine.
4. On an incline, chock the wheels or tracks.
5. Take the key, and leave the machine locked as your site requires.

Daily Maintenance

• Grease points on the manufacturer's chart. Skipping grease wears out pins and bushings, which cost far more than grease.
• Clean radiator screens. Overheating kills engines.
• Drain water from fuel separators.
• Shut off the engine before fueling. Allow no smoking or open flame near it. Keep the nozzle in contact with the tank, do not overfill, and clean up any spills.

Check Your Understanding

1. You climb on an excavator set up by another operator. You push the left stick forward, and the boom moves. Which pattern is this?

The backhoe pattern. Before you dig, confirm the pattern or change the setting, then test each control slowly.

2. The house is turned around and you want to travel forward. How do you know which way the tracks will go?

Look at the drive sprockets. With them in front of you, the travel controls are reversed.

3. On the walk-around, the hydraulic sight glass reads low, and there is no visible leak. What do you do?

Report it and find out why before you operate. Do not just top it off.

4. A 40,000-pound machine has 6,000 square inches of track on the ground. What is the ground bearing pressure?

40,000 / 6,000 = about 6.7 psi.

5. You are lifting a pipe with a rated excavator when you feel the rear of the tracks start to rise. What now?

Lower the load to the ground immediately.

Key Takeaways

• A walk-around comes first, every shift.
• The swing radius of the counterweight is a danger zone.
• ISO is the most common excavator pattern, but confirm it on every machine.
• Stop all movement when a spotter signals stop.
• Keep blades and buckets low, and lower them to park.
• Stay at least 10 feet from power lines, and more at higher voltages.