Heavy Equipment Glossary

Spec sheets and jobsite conversations are full of abbreviations. This glossary explains the ones you will meet most often on Worksite Machines.

A–C

AdBlue / DEF (Diesel Exhaust Fluid). A urea solution injected into the exhaust of modern diesel engines to reduce nitrogen oxide emissions in the SCR system. Required on most Tier 4 Final and Stage V machines.

ADT (Articulated Dump Truck). An off-road truck with a pivot between the cab and the dump body, giving all-wheel drive traction on soft ground. See articulated dump trucks.

Arm (stick). The section of an excavator's front end between the boom and the bucket. A longer arm adds reach and depth but reduces digging force and lift capacity.

Articulated steering. Steering by bending the machine's frame at a central joint, used on wheel loaders, ADTs and many forestry machines.

Auxiliary hydraulics. Extra hydraulic circuits that power attachments such as breakers, augers and tilt buckets.

Blade capacity. The volume of material a dozer blade can carry, usually in cubic metres or cubic yards, calculated by a standard (SAE J1265 or ISO 9246).

Boom. The main lifting arm of an excavator, loader, crane or telehandler.

Breakout force. The maximum force a loader or excavator can exert at the bucket edge to break material loose. Excavators quote separate bucket and arm (stick) digging forces.

Bucket capacity (heaped). The volume of a bucket loaded to a standard 1:1 or 2:1 heap above the strike-off plane, per ISO 7451 / SAE J296.

Counterweight. Mass at the rear of a machine that balances loads at the front. Removable counterweight is common on cranes and large excavators to meet transport limits.

CTL (Compact Track Loader). A skid-steer-style loader on rubber tracks. See compact track loaders.

Cushion tire. A solid rubber tyre pressed onto a steel band, used on indoor forklifts working on smooth concrete.

D–H

Digging depth. The maximum depth an excavator bucket tip can reach below ground level, usually quoted with a specific boom and arm combination.

DPF (Diesel Particulate Filter). A filter that traps soot in the exhaust. It is periodically cleaned by burning off the soot (regeneration).

Drawbar power. The power a tractor or crawler can deliver as pulling force at the hitch, always less than engine power.

Dump height / dump clearance. The height under the edge of a fully raised and tipped loader bucket; it decides which trucks a loader can load.

Final drive. The last gear reduction between the hydraulic or mechanical drive and the track sprocket or wheel.

Gross power. Engine power measured without fan, alternator and other parasitic loads (SAE J1995). Always higher than net power.

Ground pressure. Machine weight divided by the area of its tracks or tyres in contact with the ground, in kPa or psi. Lower is better on soft ground.

GVW (Gross Vehicle Weight). The total weight of a truck plus its maximum payload.

Hydrostatic drive. A transmission in which an engine-driven pump powers hydraulic motors at the wheels or tracks, giving smooth, stepless speed control.

I–O

ISO 9001 / ISO 6015. Standards bodies' references you will see on spec sheets; ISO 6015 defines how excavator digging forces are measured.

LGP (Low Ground Pressure). A dozer or excavator configuration with wider tracks to reduce ground pressure on soft or wet soils.

Lift capacity. The load a machine can lift at a given radius and height without exceeding stability or hydraulic limits. Read the full load chart, not one number.

Load chart. The table or diagram that shows a crane's, telehandler's or excavator's safe lifting capacity at each boom length, angle and radius.

Machine control. GNSS or laser-based systems that guide or automatically control a blade or bucket to a digital design.

Net power. Engine power available at the flywheel with all standard accessories running (SAE J1349 / ISO 9249). The fairer number for comparing machines.

Operating weight. The weight of a machine ready to work, typically including fuel, fluids, a standard bucket or blade and an operator. Definitions vary by manufacturer.

OEM (Original Equipment Manufacturer). The company that built the machine or part.

P–S

Payload. The rated load a truck, loader or forwarder can carry.

PTO (Power Take-Off). A rotating shaft on a tractor that drives implements such as mowers, balers and pumps.

Rated operating capacity (ROC). For skid steers and CTLs, the load the machine can carry safely; usually 50% of tipping load for wheeled machines and 35% for tracked ones (ISO 14397).

Reduced tail swing / zero tail swing (ZTS). Excavators whose upper structure stays within or close to the track width as it rotates, allowing work next to walls and traffic.

Ripper. A large tooth or set of teeth at the rear of a dozer used to break hard ground or rock before pushing.

ROPS / FOPS. Roll-Over Protective Structure and Falling Object Protective Structure: the certified cab frame that protects the operator.

SCR (Selective Catalytic Reduction). An exhaust after-treatment system that uses DEF/AdBlue to convert nitrogen oxides into nitrogen and water.

Stage V. The current European Union emissions standard for non-road diesel engines. Requires a DPF for most power bands from 19 to 560 kW.

T–Z

Telematics. Systems that transmit a machine's location, hours, fuel use and fault codes to the owner. Examples include Cat Product Link, Komatsu KOMTRAX and JCB LiveLink.

Tier 4 Final. The current U.S. EPA emissions standard for non-road diesel engines, broadly equivalent to EU Stage IV.

Tipping load. The load at which a loader's rear wheels or tracks lift off the ground. Rated capacities are calculated as a percentage of it.

Tractive effort / drawbar pull. The pulling force a machine can generate at its tracks or wheels, limited by power, weight and ground conditions.

Undercarriage. The tracks, rollers, idlers, sprockets and frames of a crawler machine. Often the single largest maintenance cost on a dozer or excavator. Read our undercarriage guide.

Variable-geometry turbo (VGT). A turbocharger that adjusts its vane angle to deliver boost across a wider engine speed range.

Wheelbase. The distance between front and rear axles; longer wheelbases improve ride and stability.