Digger Derricks: A Comprehensive Overview
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Digger Derricks
This workforce solution is funded by the IHUM Consortium which is 100% financed through a $15,000,000 grant from the U.S. Department of Labor’s Employment & Training Administration.
The product was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability, or ownership.
This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Digger Derricks
A digger derrick is a truck-mounted, hydraulically operated piece of equipment
designed to do two basic jobs:
◦
Lift heavy loads
◦
Dig with an auger
The Derrick
The derrick is the part of the truck that does the lifting
It consists of a pedestal/turntable assembly
The pedestal is mounted on a truck chassis
Where the pedestal is mounted determines it classification
◦
If the pedestal is mounted at the back of the truck it’s a “rear mount” unit
◦
If the pedestal is mounted directly behind the cab of the truck it’s a “center mount” unit
◦
If the pedestal is mounted at the rear of the truck but off center (usually to the passenger
side) it’s a “corner mount” unit
Digger derrick typically have outriggers located at each corner of the bed that are used to
stabilize the unit
Auger
Boom Tip Sheave
Pole Grabbers
Pedestal
Outrigger
Cont – The Derrick
The boom is attached to the pedestal and typically has two or more
sections that can be extended or retracted
The boom can be raised, lowered and rotated 360
0
Pole grabbers located at the end of the boom are hydraulically
operated and are used to “grab” a pole
Winches can be mounted on the tip of the boom or on the pedestal
Controls of a Digger Derrick
The controls of a digger derrick are mounted on the pedestal
(remote controlled digger derricks won’t be discussed in this lesson)
The pictures and examples used in this lesson are one type of unit;
controls and how they operate will vary depending on the
manufacturer
How a digger derrick responds will depend on the lever that’s
selected and whether you push or pull on the lever
There is a throttle located on the pedestal to control the speed of
the truck’s engine….increasing the speed increases the power
The Digger
The digger mechanism is a hydraulically operated motor that drives the
auger…………..augers come in a variety of sizes
The digger is attached to the under side of the boom by the digger hanger
bracket
The auger, which resembles a large drill bit, is connected to the shaft of the
digger mechanism by a large pin
When not in use the auger is stowed in a bracket mounted on the side of the
boom……it remains in the bracket with the use of a stow lock
When preparing to use the auger the stow lock is released and the auger is
“unwound” with a hoist line attached to a hook located near the top of the
auger
Operating a Digger Derrick
The maximum lifting capacity of a digger derrick depends on three factors:
◦
The stability of the unit and the surface it’s on
◦
The structural strength of the derrick
◦
The power of the hydraulic system
Also, whether or not a digger derrick can it’s maximum capacity depends on the
position of the boom…there are two factors:
◦
The hook radius
◦
The sheave height
Most digger derricks have a chart located near the controls that indicates the lift
capacity of the unit with the boom in various positions
Digger Derrick Operation
CAUTION!! ENSURE THE BOOM WILL HAVE CLEARANCE FROM ENERGIZED LINES
BEFORE TAKING IT OUT OF THE CRADLE!!
The first step in using a digger derrick is to plan the job; the plan will include
where and how the truck is positioned
If possible, position the truck so all the work can be done off the back
Once the truck is in position and the work area is marked and coned off (if
applicable, and per the Manual of Uniform Traffic Control Devices)
The next step is to engage the power take-off and lower the outriggers to level
the truck. Often the outriggers need to be lowered onto wooden or metal pads
(this can vary depending on applicable safety rules)
Cont – Digger Derrick Operation
Following is a typical procedure for digging a hole:
First, make certain all underground facilities have been located prior to conducting any
excavating activities (Iowa One Call – Dial 811)
Raise the boom to a 45
0
angle
Rotate the boom until it’s positioned to the back so it will clear the truck when unrolled
Make certain the boom is fully retracted
Make certain all personnel are clear of the auger before it’s unrolled
Unpin the auger or open the stowage lock and unroll the auger; this is usually done in a
counter clockwise manner
Once the auger is fully unrolled and free of the hoist line position it over the location
where the hole will be dug
Cont – Digger Derrick Operation
When the point of the auger is placed on the location to dig the hole the person on the ground
will assist in making certain the auger is straight up and down (typically the person on the
ground will position them self 90
0
from the truck operator)
To begin digging the auger is turned clockwise while at the same time applying slight down-
pressure with the boom
Once the auger is full of dirt it’s lifted out and positioned next to the hole
The auger is cleaned by slowly rotating it counter clockwise when personnel on the ground
shovel the dirt from the auger
Depending on the ground conditions and length of the pole being set, the hole likely will need to
be dug in increments
◦
The formula for determining how deep to dig the hole is 10% of the length of the pole plus 2
feet (Example – 10% of a 40’ pole is 4 feet….plus 2 feet…the depth for the hole is 6 feet)
Mini Derricks
Mini derricks are used to dig, set and/or remove poles, haul
equipment and in some instances used as an aerial lift in
locations that are not accessible to full sized equipment
Often the tracks of the unit can be retracted so it will fit
through a gate in a chain link fence
If a mini derrick is going to be used to set or replace a pole is
can be used to haul the pole to the work location
As with a regular digger derrick, it’s essential to make certain
the unit is appropriately stabilized
These units are often remote controlled…..whoever is
operating the unit must be familiar with all aspects of the
controls
These are the standard industry color codes
used when marking/location underground
facilities
Iowa One Call must be contacted prior to
performing any excavating activities. They can
be reached at 800-292-8989 or Dial 811
Except in an emergency, notice must be given
to Iowa One Call 48 hours in advance (not
counting weekends or holidays) of any
excavating activities occurring
Call before you dig………….it’s the law!!
Learn about digger derricks, funded by the IHUM Consortium, designed for heavy lifting and digging tasks. Explore the components like the derrick, boom, pole grabbers, controls, and more. Discover how these versatile equipment are operated and their essential features.
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Presentation Transcript
This workforce solution is funded by the IHUM Consortium which is 100% financed through a $15,000,000 grant from the U.S. Department of Labors Employment & Training Administration. The product was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such i This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Digger Derricks
Digger Derricks A digger derrick is a truck-mounted, hydraulically operated piece of equipment designed to do two basic jobs: Lift heavy loads Dig with an auger
The Derrick The derrick is the part of the truck that does the lifting It consists of a pedestal/turntable assembly The pedestal is mounted on a truck chassis Where the pedestal is mounted determines it classification If the pedestal is mounted at the back of the truck it s a rear mount unit If the pedestal is mounted directly behind the cab of the truck it s a center mount unit If the pedestal is mounted at the rear of the truck but off center (usually to the passenger side) it s a corner mount unit Digger derrick typically have outriggers located at each corner of the bed that are used to stabilize the unit
Pole Grabbers Boom Tip Sheave Auger Pedestal Outrigger
Cont The Derrick The boom is attached to the pedestal and typically has two or more sections that can be extended or retracted The boom can be raised, lowered and rotated 3600 Pole grabbers located at the end of the boom are hydraulically operated and are used to grab a pole Winches can be mounted on the tip of the boom or on the pedestal
Controls of a Digger Derrick The controls of a digger derrick are mounted on the pedestal (remote controlled digger derricks won t be discussed in this lesson) The pictures and examples used in this lesson are one type of unit; controls and how they operate will vary depending on the manufacturer How a digger derrick responds will depend on the lever that s selected and whether you push or pull on the lever There is a throttle located on the pedestal to control the speed of the truck s engine .increasing the speed increases the power
The Digger The digger mechanism is a hydraulically operated motor that drives the auger ..augers come in a variety of sizes The digger is attached to the under side of the boom by the digger hanger bracket The auger, which resembles a large drill bit, is connected to the shaft of the digger mechanism by a large pin When not in use the auger is stowed in a bracket mounted on the side of the boom it remains in the bracket with the use of a stow lock When preparing to use the auger the stow lock is released and the auger is unwound with a hoist line attached to a hook located near the top of the auger
Operating a Digger Derrick The maximum lifting capacity of a digger derrick depends on three factors: The stability of the unit and the surface it s on The structural strength of the derrick The power of the hydraulic system Also, whether or not a digger derrick can it s maximum capacity depends on the position of the boom there are two factors: The hook radius The sheave height Most digger derricks have a chart located near the controls that indicates the lift capacity of the unit with the boom in various positions
Digger Derrick Operation CAUTION!! ENSURE THE BOOM WILL HAVE CLEARANCE FROM ENERGIZED LINES BEFORE TAKING IT OUT OF THE CRADLE!! The first step in using a digger derrick is to plan the job; the plan will include where and how the truck is positioned If possible, position the truck so all the work can be done off the back Once the truck is in position and the work area is marked and coned off (if applicable, and per the Manual of Uniform Traffic Control Devices) The next step is to engage the power take-off and lower the outriggers to level the truck. Often the outriggers need to be lowered onto wooden or metal pads (this can vary depending on applicable safety rules)
Cont Digger Derrick Operation Following is a typical procedure for digging a hole: First, make certain all underground facilities have been located prior to conducting any excavating activities (Iowa One Call Dial 811) Raise the boom to a 450 angle Rotate the boom until it s positioned to the back so it will clear the truck when unrolled Make certain the boom is fully retracted Make certain all personnel are clear of the auger before it s unrolled Unpin the auger or open the stowage lock and unroll the auger; this is usually done in a counter clockwise manner Once the auger is fully unrolled and free of the hoist line position it over the location where the hole will be dug
Cont Digger Derrick Operation When the point of the auger is placed on the location to dig the hole the person on the ground will assist in making certain the auger is straight up and down (typically the person on the ground will position them self 900 from the truck operator) To begin digging the auger is turned clockwise while at the same time applying slight down- pressure with the boom Once the auger is full of dirt it s lifted out and positioned next to the hole The auger is cleaned by slowly rotating it counter clockwise when personnel on the ground shovel the dirt from the auger Depending on the ground conditions and length of the pole being set, the hole likely will need to be dug in increments The formula for determining how deep to dig the hole is 10% of the length of the pole plus 2 feet (Example 10% of a 40 pole is 4 feet .plus 2 feet the depth for the hole is 6 feet)
Mini Derricks Mini derricks are used to dig, set and/or remove poles, haul equipment and in some instances used as an aerial lift in locations that are not accessible to full sized equipment Often the tracks of the unit can be retracted so it will fit through a gate in a chain link fence If a mini derrick is going to be used to set or replace a pole is can be used to haul the pole to the work location As with a regular digger derrick, it s essential to make certain the unit is appropriately stabilized These units are often remote controlled ..whoever is operating the unit must be familiar with all aspects of the controls
Call before you dig.its the law!! These are the standard industry color codes used when marking/location underground facilities Iowa One Call must be contacted prior to performing any excavating activities. They can be reached at 800-292-8989 or Dial 811 Except in an emergency, notice must be given to Iowa One Call 48 hours in advance (not counting weekends or holidays) of any excavating activities occurring
