Lattice Boom: March 12, 2023 Flashcards
On lattice boom cranes with power load lowering mounted on the hoist, a heavy load should be lowered by using which functions listed below
Power load lowering feature
and the foot brake
a pin connected lattice boom is being dismantled. After connecting the equalizer (bridle) to the connecting lugs on the boom butt. which boom connecting pins should be removed first
lower connection pins,
located at and ahead of the equalizer
when using a mobile crane on a barge, the crane’s load capacity ratings will be
replaced by a list chart
How many broken wires are permitted at the end connection of a standing pendant line before it must be taken out of service
1
When assembling a lattice boom on most mobile cranes and using inserts of different lengths, which insert section generally should be closest to the boom butt section
10 ft
Backward stability of a mobile crane is tested in which configuration
basic boom
at maximum angle
with no load
the device that automatically stops the boom when it nears the cranes maximum angle is called the
boom hoist limiting device
What does the term “jib offset” mean when refferring to a lattice boom mobile crane
jib angle to boom
Manufacturer specifications permit only a certain amount of lattice boom to be suspended out past the connection point of the pendants during assembly or disassembly of the boom. The term for that length of boom that is suspended is called the
cantilever length
On the majority of friction style mobile cranes the power is transferred to the torque converter by which component
Master clutch
When lattice boom is being disassembled or shortened, it is extremely important to:
never touch any pin on boom section
between the pendant attachment points
And crane
When swinging a suspended load on any lattice boom crane, the most ground pressure will be exerted over which position
Corner
On a lattice boom truck crane, the main boom length is measured from the:
center of the heel pins
to the center of the tip sheave pins
How should the gantry of a lattice boom crane be positioned when hoisting a suspended load?
Highest position
When assembling or disassembling lattice booms, when is it safe to work under the boom
None of the above
When handling boom sections, where is the best location for slings to be attached”
pin connection points
at the end of the top chords
Booms that are being assembled or disassembled on the ground with or without support of the boom harness should be
securely blocked
to prevent dropping of the boom and boom sections
When installing boom pins on lattice boom cranes, which direction should the connection pins be pointing?
outward and away from center
A hydraulic lattice boom crane is equipped with an anti two block lockout device. When the device is activated which functions should be disabled
hoist and boom down
According to OSHA, when is it safe to hoist loads with a lattice boom crane below energized power lines.
The boom is kept 10 ft away from the power line for 360 degrees
A crane loses stability when its leverage on the load is:
less than the load’s leverage on the crane
What is the design factor required when using rotation resistant wire rope slings and lifting personnel in a platform suspended from a mobile crane
3.5
A mobile crane’s jib is offset at 15 degrees versus the original 30 degree offset, but the boom angle remains unchanged. In this situation, the load radius would:
increase
On mobile cranes, what information does the boom angle indicator display to the operator
angle of boom to vertical
What boom position produces the least amount of ground pressure on a lattice boom crawler crane
side
What should the operator do if he or she cannot properly level the crane?
don’t operate the crane
What effect does having the crawlers retracted have on a mobile crawler crane with a long boom
Decrease in capacity
A mobile crawler crane is on a barge, what item listed below is important to check
Crane is secured to the barge
When operating a lattice boom crawler crane what is the least stable allowable quadrant of operation
Front
Tipping capacities of lattice boom crawler cranes are based on what percentage of tipping
75%
Approved blocking placed under the tips of the tracks on some mobile crawler cranes will;
increase a crane’s stability
The tipping axis over the side on most lattice boom crawler cranes is generally inline with what component?
Track rollers
