ce-excavating and lifting
TRANSCRIPT
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Excavating and Lifting
M.C. Josept Revuelta Acosta
ProfessorUniversity of Veracruz
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Shovels
The hydraulic shovel is also called a front shovel
or hydraulic excavator-front shovel.
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Shovels
The hydraulic shovel digs with a combination of
crowding force and breakout force.
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Shovels
Both front-dump and bottom-dump buckets are
available for hydraulic sholves.
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Shovels
Although the shovel has a limited ability to dig
below track level, it is most efficient when
digging above track level. The shovel shouldhave a vertical face to dig against for most
effective digging. This surface, known as the
digging face, is easily formed when excavating
a bank or hillside. The ability of the shovel toform its own roadway as it advances is a major
advantage.
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Shovels
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Shovels
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Shovels
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Shovels
Other possible applications of the shovel include
dressing slopes, loading hoppers, and digging
shallow trenches.
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Shovels-Production Estimating
Production for hydraulic shovels mat be
estimated using following equation:
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Shovels-Production Estimating
Exercise:
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Shovels- Job Management
The two major factors controlling shovel
production are the swing angle and lost time
during the production cycle. Therefore, the
angle of swing between digging and dumpingpositions should always be kept to a mnimum.
Haul units must be positioned to minimize the
tome lost as units enter and leave the loadingposition.
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Draglines
The dragline is a very versatile machine that
has the longest reach for digging and dumping
of any member of the crane-shovel family. It
can dig from adove machine level to significantdepths in soft to medium-hard material.
Bucket teeth and weight produce digging
action as the drag cable pulls the bucketacross the ground surface.
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Draglines
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Draglines
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Draglines
Buckets are available in a wide range of sizes
and weights, solid and perforated.
While the dragline is a very versatile
excavator, it does not have the positive
digging action or lateral control of the sholve.
Hence the bucket may bounce or move
sideways during hard digging.Also, more spillage must be expected in
loading operations than would occur with a
shovel.
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Draglines-Production Estimating
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Draglines-Production Estimating
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Draglines-Production Estimating
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Draglines-Production Estimating
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Draglines-Production Estimating
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Draglines-Job Management
Trial operations may be necessary to select the
boom length, boom angle, bucket size and weight,
and the attachment position of the drag chain that
yield maximum production. As in shovel operation,maximum production is obtained with a minimum
swing angle. In general, the lightest bucket capable
of satisfactory digging should be used, since this
increases the allowable bucket size and reduces
cycle time. It has been found that the most efficient
digging area is located within 15 forward and back
of a vertical line through the boom point.
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Draglines-Job Management
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Backhoes
A backhoe (or simply hoe) is an excavator
designed primarily for excavation below grade.
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Backhoes
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Backhoes
Back hoe digs by pulling the dipper back toward
the machine; hence the name backhoe. The
backhoe shares the characteristics of positive
digging action and precise lateral control with the
shovel. Cable-operated backhoes exist but are
largely being replaced by hydraulic models
because of their superior speed and ease ofcontrol. Backhoe attachments are also available for
loaders and tractors.
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Backhoes
The backhoe is widely utilized for trenching work. In addition to
excavating the trench, it can perform many other trenching
functions, such as laying pipe bedding, placing pipe, pulling
trench shields, and backfilling the trench.
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Backhoes
A special form of hydraulic excavator which utilizes a rigid
telescoping boom in place of the boom and dipper arm of a
conventional hydraulic backhoe.
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Backhoes-Production Estimating
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Backhoes-Production Estimating
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Backhoes-Production Estimating
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Backhoes-Production Estimating
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Backhoes-Production Estimating
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Backhoes-Production Estimating
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Backhoes-Job Management
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ClamshellsWhen the crane-shovel is equipped with a crane
boom and clamshell bucket, it becomes an
excavator known as a clamshell. The clamshellis capable of excavating to great depths but
lacks the positive digging action and precise
lateral control of the shovel and backhoe.
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Clamshells
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Clamshells
Clamshells are commonly used for excavating
vertical shafts and footings, unloading bulk
materials from rail cars and ships, andmoving bulk material from stockpiles to bins,
hoppers, or haul units.
No standard production tables are available
for the clamshell.
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Clamshells
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Clamshells
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Clamshells
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Clamshells
The maximum allowable load (bucket weight
plus soil weight) on a clamshell should be
obtained from the manufacturer's clamshellloading chart for continuous operation. If a
clamshell loading chart is not available, limit
the load to 80% of the safe lifting capacity
given by the crane capacity chart for rubber-tired equipment or 90% for crawler-mounted
equipment.