NCCER Heavy Equipment flashcards
NCCER Heavy Equipment · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Swing radius
- The arc swept by an excavator's counterweight and attachment as the house rotates. Personnel stay outside it because the tail swing can exceed the track width.
- Three points of contact
- A mounting rule requiring two hands and one foot, or two feet and one hand, on the machine at all times to prevent falls when entering or exiting equipment.
- Call 811 before digging
- The free utility locate notification made before excavation. Locators mark buried lines, and digging inside the marked tolerance zone must be done by hand.
- ROPS
- Roll-over protective structure: a frame that protects the operator if the machine overturns. It must never be welded, drilled, or modified, and it requires a worn seat belt.
- Walk-around inspection
- The pre-shift check in which the operator circles the machine looking for leaks, damaged hoses, loose pins, worn tires or tracks, and missing guards or safety devices.
- Hour meter
- A gauge that records machine running time. Maintenance intervals, oil changes, and filter service are scheduled from the hours it shows rather than from calendar dates.
- Track tension
- The amount of slack in a crawler track. Too loose causes derailment, while too tight accelerates wear on pins, bushings, and drive sprockets.
- Stop hand signal
- Arm extended horizontally to the side with the palm down, swung back and forth. The operator must stop the machine immediately when this signal is given.
- Emergency stop signal
- Both arms extended horizontally to the sides with palms down, swung back and forth, telling the operator to shut down movement at once.
- Load radius
- The horizontal distance from the machine's rotation center to the load. Lifting capacity decreases as the radius increases, so the load chart must be consulted.
- Swell factor
- The percentage by which soil volume increases when excavated from its natural bank state. Swell equals loose volume minus bank volume, divided by bank volume, times 100.
- Load factor
- Bank volume divided by loose volume for a given soil. Multiplying a loose cubic yard quantity by the load factor converts it to equivalent bank cubic yards.
- Type A soil
- OSHA classification for cohesive soil with an unconfined compressive strength of 1.5 tons per square foot or more. It cannot be fissured, subject to vibration, or previously disturbed.
- Optimum moisture content
- The water content at which a soil compacts to its maximum dry density. Adding or removing water from this point lowers the density that can be achieved.
- Protective system
- Shoring, shielding, sloping, or benching used to protect workers from cave-ins. It is required in trenches 5 feet deep or more unless the excavation is entirely in stable rock.
- Trench box
- A prefabricated shield that protects workers inside a trench. It does not shore the walls and must be rated, inspected, and installed according to the manufacturer's instructions.
- Spoil pile setback
- Excavated material and equipment are kept at least 2 feet back from the trench edge to reduce surcharge loading that can contribute to a cave-in.
- Trench definition
- An excavation that is deeper than it is wide and no more than 15 feet wide at the bottom. Deeper or wider cuts are classified as excavations instead.
- Benchmark
- A fixed point of known elevation used as the reference for all grade work on a site. Other elevations are measured from it or transferred from it.
- Cut and fill
- Cut equals existing elevation minus design elevation when positive. Fill equals design elevation minus existing elevation when the ground must be raised.
- Percent grade
- Rise divided by run, multiplied by 100. A 1 percent grade rises or falls 1 foot over a horizontal distance of 100 feet.
- Slot dozing
- A dozer technique of pushing in the same channel repeatedly so the blade loads are contained by the ridges, reducing spillage and increasing production.
- Loader cycle
- The four steps of loader production: load the bucket, travel to the truck, dump, and return. Cycle time is the main control on production.
- Push loading
- A dozer pushing the rear of a scraper during the cut to shorten load time and increase the load carried, raising production in stiff or tough soils.
- Scraper bowl
- The open, apron-controlled container on a scraper that cuts, holds, and dumps soil. It loads best in sandy or loamy material, not in rock.
- Moldboard
- The curved blade mounted mid-frame on a motor grader. Its angle, pitch, and side shift shape and move material for grading, ditching, and road crowning.
- Backhoe stabilizers
- Hydraulic legs lowered to lift and level the rear of a backhoe loader before digging. They transfer digging forces into the ground and keep the machine from moving.
- Grader articulation
- A joint that lets a motor grader's front frame swing relative to the rear, shortening the turning radius and allowing the blade to be offset for bank cutting.
- Excavator tail swing
- The distance the counterweight extends beyond the tracks as the house rotates. Reduced-tail-swing and zero-tail-swing machines minimize it for tight work areas.
- Competent person
- An individual capable of identifying existing and predictable hazards and authorized to take prompt corrective action, such as stopping work or ordering a trench evacuated.
- Slope stake
- A stake set beyond the edge of construction that marks where the designed cut or fill slope intersects the original ground surface at the catch point.
- Hydraulic injection injury
- A pinhole leak of pressurized hydraulic oil can pierce the skin and cause severe injury or amputation, so leaks are checked with cardboard, never a bare hand.