Transcript Trucks and Loaders - Supplemental Teaching Resources

Matching Front End
Loaders
©Dr. B. C. Paul 2000
Production Calculations


Picking up the Example - we
want a loader to go with our 3
Cat 773 58 ton dump trucks to
produce 1,000,000 tons per year
First Need a Bucket that can fill
in a reasonable # of passes
•
•
•
•
44.6
44.6
44.6
44.6
yd3/
yd3/
yd3/
yd3/
6
5
4
3
=
=
=
=
7.43 yd3 bucket
8.92 yd3 bucket
11.15 yd3 bucket
14.87 yd3 bucket
Real Buckets Don’t Fill
All the Way
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Assume a good general factor
0.9
Target Bucket/ Dipper Sizes
•
•
•
•
7.43 / 0.9 = 8.25 yd3 for 6 pass
8.92 / 0.9 = 10 yd3 for 5 pass
11.15 / 0.9 = 12.5 yd3 for 4 pass
14.87 / 0.9 = 16.5 yd3 for 3 pass
Try Matching Up a FEL
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Bucket Size Ranges Suggest
Candidate Machines
• 988B with 8.25 yd3 general purpose
bucket will do 6 pass
• 992 with a 13.5 yd3 rock bucket will do 4
pass

988 seems a bit light - bucket is
boarder-line, general purpose
bucket is a little large - better
check tipping closely
Actual Bucket Fill Could be
Constrained by Material or
Truck
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Material Constraints
• Blasted Rock
• Poorly Blasted 0.6 to 0.75
• Average 0.75 to 0.9
• Well Blasted 0.8 to 0.9
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Truck Constraints
• 988 needs 0.9 for 6 pass load
• 992 11.15 yd3 / 13.5 yd3 = 0.83
Analyzing the Options
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Limestone tends to break into
blocks which usually will create
problems with high end fills
988 can only work in a
reasonable number of passes
with a potentially light bucket
and the maximum fill factor abandon this choice
Sizing Up the Match on a
992
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Ideal Match for 4 pass load is 0.83
which is a very realistic range for
the material
• Use a 0.83 predicted fill and consider
that trait matched
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Check the Loading Height
• 992 has 13 ft 8 inches clearance with
bucket at 45 deg full dump
• Need 12 ft 2 inches loading height
• Looks Like another match
Other Aspects of the
Loading Match
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We are planning to heap our truck that means pile is higher at the
center than side of truck
15.5 feet wide on truck
thus 7.25 feet to center of bed
rated with 2 to 1 slope so heap
height is 16 ft 1/2 inch
Hinge Point of 992 is 20 ft 7 inches
so should barely be able to dump
More Match Checking
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
992 reach at full lift is 7 ft 7
inches
To Center Load on Truck is 7 ft
3 inches
• (Of course the 992 reach is from
machine - not edge of truck but
should be ok)
Need to Check Tipping Loads
to Make Sure Machine is
Stable
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11.15 yd3 in bucket * 2,600
lb/yd3 = 28,990 lbs
Check 992 rated full turn tipping
load is 107,877 lbs
Loaded bucket should carry
less than 1/2 the full turn
tipping load (its rated with full
lubricant and fuel load on level
ground)