Construction Equipment: Excavating and Lifting

Practice questions covering types of excavating equipment, hydraulic attachments, production estimation formulas, and machine components.

What is the definition of an excavator?

A power-driven digging machine that includes hydraulic excavators and members of the cable-operated crane-shovel family.

Who developed the machine in 1836 that mechanically duplicated manual digging and led to the crane-shovel family?

William S. Otis

Which family of construction machines includes the shovel, backhoe, dragline, clamshell, mobile crane, and pile driver?

The crane-shovel family

What are the primary advantages of hydraulic excavators over cable-operated machines?

Faster cycle time, higher bucket penetrating force, more precise digging, and easier operator control.

Which excavator attachment is used for drilling holes for poles, posts, soil sampling, and ground improvement?

Auger

What is the function of a 4-in-1 bucket?

A multipurpose bucket capable of performing as a clamshell, dozer, scraper, or conventional excavator bucket.

Which bucket attachment is designed with a flat bottom and tapered sides to reduce the chance of soil cave-in?

Sand bucket

What are the three major assemblies of excavators and crane-shovels?

1. A carrier or mounting; 2. A revolving superstructure containing the power and control units; 3. A front-end assembly.

What is 'Struck capacity' in the context of excavator buckets?

The bucket capacity when the load is struck off flush with the bucket sides.

Define 'Heaped volume' for excavator production.

The maximum volume that can be placed in the bucket without spillage based on a specified angle of repose for the material.

In the production estimation formula $Production(LCY/h) = C \times S \times V \times B \times E$, what does the variable $S$ represent?

Swing-depth factor

In the production estimation formula $Production(LCY/h) = C \times S \times V \times B \times E$, what does the variable $B$ represent?

Bucket fill factor

What is a backhoe (or hoe) primarily designed for?

Excavation below grade by pulling the dipper back toward the machine.

What combination of forces does a hydraulic shovel use to dig?

$Crowding\,force$ and $breakout\,(or\,prying)\,force$

Which machine is the most versatile with the longest reach for digging and dumping in the crane-shovel family?

Dragline

What are the common uses for a clamshell?

Excavating vertical shafts and footings, unloading bulk materials from rail cars and ships, and moving bulk materials from stockpiles to bins or hoppers.

What is 'Plate line capacity'?

The bucket volume contained within the bucket when following the outline of the bucket sides.

What specific excavator attachment is used to drill blast holes?

Rock drill

Which attachment is used to process scrap metal and for demolition?

Shear

How is 'Water line capacity' determined for a bucket?

It assumes a level of material flush with the lowest edge of the bucket, representing the level resulting if the bucket were filled with water.