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Loading and Hauling

Loading and Hauling. Cycle Time = Fixed Time + Variable Time Fixed Time = spot time, load time, maneuver time, Dump time Variable Time = travel time Resistance Total Resistance = Rolling Resistance + Grade Resistance Rolling Resistance due to tire flexure and surface penetration

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Loading and Hauling

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  1. Loading and Hauling

  2. Cycle Time = Fixed Time + Variable Time • Fixed Time = spot time, load time, maneuver time, Dump time • Variable Time = travel time • Resistance • Total Resistance = Rolling Resistance + Grade Resistance • Rolling Resistance due to tire flexure and surface penetration • Grade Resistance due to grade of incline

  3. Rolling Resistance • 40#/ton on hard surface rubber tired • 30#/ton if radials • T4-1 • Rolling Resistance increases 30#/ton/1” penetration • Rolling Resistance Factor = 40# + (30# * inches penetration) • Rolling Resistance = Rolling Resistance Factor * tons

  4. Grade Resistance • % of vehicle weight acting parallel to incline surface • Negative going downhill Positive going uphill • 20#/ton • Grade Resistance Factor = (20# * % grade) • Grade Resistance = Grade Resistance Factor * tons • Effective Grade (%) = % Grade + Rolling Resistance/20

  5. Altitude • 3% power loss per 1000 ft • Using turbocharger allows power to stay constant up to 10,000 ft

  6. Traction • Power available to move vehicle • Rimpull – used for wheeled vehicles • Pull available at rim of driving wheel • Drawbar pull – used for tracked vehicles • Power available at hitch • Maximum usable pull = coefficient of traction * wt on driven wheels (for tracked vehicles and all wheel drive vehicles this is total wt) • T 4-2

  7. Performance Curve • Maximum speed for a given load F 4-1, 4-2 • Retarder curves • Maximum speed going downhill in gear

  8. Travel Time • Cannot use max speed • Need to account for start up and stop • Average speed factors T 4-3 • Max spd * Ave spd factor = speed for haul

  9. Dozers • Tractor w/ front mounted earthmoving blade • Crawler • Low ground pressure (6 – 9psi) • Excellent traction • Rubber tired • Hi spd • Can compact soils • Can operate on paved surfaces

  10. Dozers • Attachments • Rakes, scarifiers, rippers • tow compactors, scrapers, wagons • Blades • F4-7, F4-8 • Performance based on power vs blade size • Hp/ ft of cutting edge -> blades ability to penetrate hard soils • Hp/loose cy -> blades ability to push soil

  11. Production • 5 bullets pg 96 show how to determine blade volume • Blade load (LCY) = 0.0139HWL • Fixed cycle time – maneuver, change gears, start loading, dump • Variable time – time to doze and return • Can decrease by using reverse to return • T4-4, 4-5

  12. Job Management • Downhill dozing • Increases blade load • Cycle time reduction • Slot Dozing • Increases blade capacity up to 50% • Blade to Blade • 2 dozers together • Combined capacity > 2x 1 dozer

  13. Care for tracks and undercarriage • Must keep tracks clean • Must keep undercarriage clean and in good repair • Don’t run at hi spd over rough terrain • Minimize turns • Try to balance left and right turns and up & down slope operation

  14. Loaders • Tractor with a front end bucket • Wheeled or tracked • Excavate soft – medium hard material • Load hoppers and haul units • Stockpile material, backfill ditches • Moving material

  15. Loaders • Wheel Loaders • High mobility • Not all terrain but low ground pressure • Modern are articulated F 4-9 • Tracked Loaders • Can operate in most soils and on steeper slopes • Slower over longer haul distances=> less productivity F 4-10 • Backhoe loader F 4-11 • Attachments – augers, snow blades, forklifts, dozer blade, crane booms

  16. Skid Steers • Small wheeled loader w/ rigid axles • Steers by braking wheels on one side • <10,000# weight • Lift capacities of 600 – 6300 # • Can also be tracked • List of attachments pg 100 • Also mini excavators

  17. Material Handlers • Rough terrain forklifts • Common Lull • Max lift 9000# • Max height > 60 ft • Move materials around site • Eliminates hand carrying or use of other equipment for carrying

  18. Loader Production • Average Bucket load x cycles per hour • Cycle time = loading, dumping, making 4 reversals in direction, traveling minimum distance T 4-6, F 4-14 • Bucket Capacity is heaped T3-1 and use fill factor T3-2 • Ex 4-7

  19. Job Management • Cutting tires major problem • L-5 tires – rock extra deep tread should be used when dealing with shot rock • Keep water out – lubricates rock /rubber cutting • Need to know tipping load – may limit amount of material in bucket • Loader size & productivity based on site limitations

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