MOVING EARTH QUICKER AND CHEAPER

TWO CONCEPTS THAT CAN REDUCE THE ENERGY TO EXCAVATE A GIVEN AMOUNT OF EARTH OR ROCK ARE DESCRIBED AND ILLUSTRATED. A SELF-PROPELLED EARTH EXCAVATOR WHICH IS OF THE SAME SIZE, POWER, SPEED AND MOBILITY AS A MODERATE SIZED CONVENTIONAL SCRAPER, CAN EXCAVATE A PATH 10 FT. WIDE BY 2 FT. WIDE, AT THE RATE OF 1,000 BANK YARDS PER HOUR, OFF- LOADING SPOIL INTO A FLEET OF INDEPENDENT HAUL VEHICLES. THE KEY CONCEPT IS THAT THE ROTARY BUCKET-WHEEL EXCAVATOR BLADES PUSH EARTH BACK AS THE SCRAPER SLICES FORWARD; THE OPPOSITE FORCES LARGELY CANCEL OUT EACH OTHER. LESS POWER IS REQUIRED BECAUSE THE WHEEL EXCAVATOR IS THE MOST EFFICIENT CONVENTIONAL EXCAVATOR. ALTHOUGH THE MACHINE IS USEFUL OVER A NARROWER RANGE OF JOBS, IT HAS THE ADVANTAGE THAT IT HAS BETTER PERFORMANCE WHERE THE TOTAL EXCAVATION IS VERY LARGE, WHERE THE HAUL LENGTH IS LONG, OR WHERE ORDINARY SCRAPERS CANNOT BE USED FOR HAULING. OTHER ADVANTAGES INCLUDE ELIMINATION OF THE PUSHER DOZER, AND ITS CONSIDERABLY LIGHER WEIGHT. THE SECOND CONCEPT DESCRIBED IS THAT OF A CONICAL BORER WHICH WOULD REDUCE THE HIGH APPLIED THRUST REQUIREMENT OF ROLLER BITS WHILE RETAINING THEIR PROVEN HIGH PERFORMANCE AND RELIABILITY. THE CONICAL HOLE GEOMETRY EXPOSES MORE ROCK TO CUTTING, THUS MAKING POSSIBLE INCREASED SPEED OF PENETRATION. IF THE AXES OF THE THREE ROLLERS ARE SKEWED, THE BIT WILL PULL ITSELF FORWARD INTO THE ROCK. A PHOTOGRAPH ILLUSTRATES A SMALL DEMONSTRATOR POWERED BY A VANE-AIR MOTOR GEARED TO ITS THREE ROLLER CUTTERS. IN THE DEMONSTRATION IN WHICH IT PULLED ITSELF UPWARD THROUGH THE CONCRETE, IT SUCCESSFULLY REAMED OUT TO 6 IN. A 3 IN. PILOT HOLE PREVIOUSLY DRILLED.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/10480594
• Publication Date: 1972-7

Media Info

• Features: Figures; Photos;
• Pagination: p. 56-7
• Serial:
  • Civil Engineering
  • Volume: 42
  • Issue Number: 7
  • Publisher: American Society of Civil Engineers
  • ISSN: 0885-7024
  • Serial URL: http://www.pubs.asce.org/ceonline/newce/html

Subject/Index Terms

• TRT Terms: Cutting; Demonstration projects; Earth; Earthwork; Economic benefits; Excavating equipment; Freight handling; Power; Rocks
• Uncontrolled Terms: Hauling
• Subject Areas: Construction; Economics; Energy; Freight Transportation; Geotechnology; Highways;

Filing Info

• Accession Number: 00215646
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 11 1974 12:00AM