Rigging Flashcards
1
Q
Of the fibre core wire ropes which offers better resistance to deterioration? Vegetable fibre (Manila, sisal, jute) or synthetic fibres (polypropylene) ?
A
Synthetics
2
Q
What is IWRC and it’s advantages?
A
Independent wire core,
Has a separate strand for the inner core. Adds about 7 1/2 % in strength and resistant to crushing
3
Q
Wire rope is made up of preformed strands. What advantage do the pre formed strands give?
A
Pre forming strands gives equal load load distribution and helps prevent unraveling when the rope is cut.
4
Q
What determines the uses for wire rope?
A
Number of strands
Number of wires per strand
Type or quality of the wire material
Nature of the core
5
Q
Wire rope that beds around sheeves and drums should have? Why?
A
Sufficient amount of wires to bend around sheaves and drums.
Smaller wires and strands is more flexible
6
Q
What are the main considerations when designing a wire rope? To imped the conditions of?
A
Corrosion
Over tension
Wear
Crushing
And rotation
7
Q
What grade wire rope is used for mine shaft lifting?
A
Grade 120/130 and 130/140
Extra extra improved plow EEIP
8
Q
Extra improved plow (EIPS) wire rope is used when higher breaking strength is needed but the _______ quality is not as good as improved plow IPS
A
Bending
15% stronger than improved plow
9
Q
Most common wire rope?
A
Grade 110/120 improved plow (IPS)
Good west resistance
High fatigue factor
High tensile strength
10
Q
Grade 100/110 plow wire rope is better for tensile strength or wear resistance?
A
Wear resistance
11
Q
The term lay refers to the ?
A
Direction of winding of both the wires in the strands and the actual rope strands
12
Q
Regular lay?
A
Wire in the strands are laid one direction
Strand in the rope are laid in the opposite direction
13
Q
Lang lay or regular lay? Wire in the strands and wire in the ropes are laid in the same way?
A
Lang lay
14
Q
Why is Lang lay best suited for high abrasion situations opposed to hoisting?
A
Because of its tendency to unwind
15
Q
What is alternate lay?
A
A right lay rope wire rope made of alternating strands of right regular lay and right Lang lay strands.
16
Q
To make a rotation resistant wire rope what would you use?
A
Outer layers and inner layers are laid in opposite directions
17
Q
How are wire ropes grouped?
A
Number of wires per stand.
18
Q
What does the number wires and patterns define?
A
The rope characteristics
19
Q
what are the four common wire rope classifications?
A
6x7 = 6 strands 3-14 wires per strand
6x19 = 6 strands 16-26 wires per strand
6x37 = 6 strands 27-49 wires per strand
8-19 = 8 strands 16-26 wires per strand
20
Q
6x7 wire rope uses?
A
Large wire, not very flexible but good abrasion resistance. should be used on large pully’s or drums. used on permanent guy-lines, ski tows and tram ways
21
Q
6x19 wire rope uses?
A
most diverse use. the more wires in a strand the more flexible
22
Q
6x37 wire rope uses?
A
most flexible, commonly used on high speed cranes, reeving hoists, power shovels. used where multiple drum layers are needed because of its resistance to crushing
23
Q
8x19 wire rope uses?
A
more flexible than 6 strand rope but has poor abrasion resistance, crushes and distorts easily. used with high speed cranes with multiple reeving.
24
Q
What is one way to check for rope stretching?
A
mark one strand on top follow it around and mark the top when it comes around. the straight point from lay to lay
25
26
Checking wire rope is one of the most important aspects of rigging equipment inspection. What are the purposes of the inspection?
Ensure safety
- ensure components will be replaced only when necessary
- provides advanced warning before something breaks
27
In severe conditions how often should a wire rope be inspected?
Weekly (daily in some applications)
General uses monthly
28
What is it called when measuring the width of wire ropes across the widest points
measuring across the crowns
29
Maximum wire rope reduction?
30
31
Number of broken wires in running rope and standing rope?
Personal hoist and material hoist running rope
6 broken wires in one rope lay
3 broken wires in one strand
Standing rope:
3 broken wires in one rope lay. 2 if it is used for personal hoist.
2 broken wires by the connections
32
When must wire rope be replaced due to wear?
When wire diameter wear is 1/3 or more
33
What are some causes of bird caging in wire rope?
Pulling through tight sheave
Wound on two small of a drum
Sudden stops
34
Formula for IWRC ultimate load?
Formula for fibre rope core ultimate load
D x D x 45
D xD x 42
35
What is the formula for SWL of wire rope?
36
5:1 swl is for what
General rigging
37
20:1 swl?
Use if possibility of injury or death due to breakage.
Elevator
38
Critical lifts with danger to personnel use a ________SWL?
10:1
39
Working load limit for single vertical hitch?
Full strength
40
Tension per sling formula?
WxN/LxH
W= weight of load
N = number of slings
L = length of slings if different length always use longest one
H = vertical distance from load to shackle
41
Ideal sling angles when using multiple slings?
60 degrees best
45 degrees
30 degrees reduces swl by almost 50 percent
42
Weight capacity of different hitches?
A = 100%
B = 200 %
C = 75 %
43
If tag is missing on synthetic sling what do you do?
Remove sling from service
44
Lifting at a 60 degree sling angle creates what kind of triangle?
Equilateral triangle.
All sides are the same
45
Minimum lifting angle should be no less than _________ degrees
45
46
A 5 degree sling angle increase the load weight how many times?
6 times
1000 lb load equals 6000lb per sling
47
When selecting slings for a lift what are some main considerations?
Load weight
Load size
Centre of gravity of the load
48
Which kind of metal wire rope must be used in a corrosive or acidic environment?
Stainless steel
49
When are galvanized wire ropes needed?
Salt water applications
50
Which grade wire rope is most common in mills? What is its breaking strength /load?
Improved plow quality grade
110-120 tons per square inch
51
Most common lay of wire rope in the industry?
Right regular lay
52
What are some advantages of Lang lay?
More flexible
Has more area in contact with drum spools or sheaves thus wearing longer.
53
Disadvantages of Lang lay?
Both ends must be fastened to prevent unwinding
Must not be used with a single part lift
Not to be used with swivels
Cannot be used for slings
Does not resist crushing
54
What happens when preformed wire ropes are cut?
Nothing, they can be spliced without seizing
55
When inspecting sheaves for wire rope what are we looking for?
56
What is a preferred method to lubricate wire rope?
Oil bath lubrication since rope opens up as it goes around the sheave.
57
Why do you not want to take wire rope off the side of a spool?
Often results in kinks
58
Proper ways to take wire off of a spool
See image
59
If cut wire is going through a hole in a drum what needs to be done to the ends?
It is good practice to braze or weld the ends of the rope then remove seizing.
60
If cutting wire rope with a torch how much extra must you cut?
6” from where you intend to use the rope
61
When winding wire rope on a drum what does the rule of hand show you?
- right hand represents right lay rope
- left hand represents left lay rope
- index finger shows the approach of the ropes
- the positioning of the back of the hand represents represents wether the rope is over wound or under wound
- position of the thumb shows where the rope is attached to the drum
62
What are the two groups of fibre ropes?
Natural and synthetic
Hemp is the most common natural rope
63
When using knots with synthetics ropes you should always finish the know with a________?
Additional safety knot to prevent slippage
64
Why are poly ropes typically used in water applications
Because they have good buoyancy
65
Which synthetic rope divides the load equally between the sheath and the core and why?
Braided synthetic rope
Even if the outer sheath is damaged 50% of the ropes strength remains in the core
66
How is fibre rope measured?
Diameter or circumference
67
What is the best working strength of new rope?
1/5th it’s breaking strength if rope is used increase safety factor
68
Why should chains only be used for hoisting when there are no other methods of slinging or rigging?
Chains break without warning.
Only use when high temperatures and abrasion is required
69
What is the only grade of chain to be used for overhead lifting?
Grade A must be stamped on the chain
8
80
800
Also are accepted variations
70
Replace chain when amount of wear equals 5% on chains smaller then 1” and replace chains over 1” when they reach _______% wear
10
71
What types of wire rope end fittings are 100% efficient if installed properly?
Poured sockets
Cappel sockets
Swagged sockets
72
If a thimble is not used how much is the efficiency decreased?
Up to 10%
73
Wire rope clips have ______% of the rope strength
80%
74
Why are saddle clips preferred to u bolt style?
Cause less damage to the rope
75
Improper placement of even one clip can reduce efficiency of the connection to_____%
40
76
Where does the saddle go on wire ropes?
On the live/long end
77
What is the correct method to connect two wire ropes together?
Make two eyes and shackle together
78
What precautions should be taken when using shackles?
All pins must be straight screw pins must be completely seated
- never replace shackle pin with a bolt
- destroy worn shackles
- when using screw pin shackle secure pin with wire to prevent unwinding
- never pull shackle at and angle
79
Unless pulling vertically eye bolts must be equipped with _______
Shoulders or collars
80
When using, shoulder type eye bolt make sure that:
Shoulder firmly contacts the work surface
- nuts are properly torqued
- threads on the bolt and tapped hole are in good condition
And?
The tapped hole for the bolt has a minimum depth of one and a half times the bolt diameter
81
When using eye bolts always make sure the eye is is in the plane of the eye, a shackle is used and???
Lifting angle is above 45 degrees.
82
When turn buckles with hook end fittings are used for hoisting make sure to apply _______ to any open hook.
Mousing
Mousing means to wire the throat of the hook closed to prevent rigging from slipping off
83
When using turnbuckles what is the preferred method to to lock the turnbuckle?
Lock nuts or wire?
Wire
Locknuts add to the load of the the threads
84
What are some things that spreader or equalizer bars perform when hoisting?
Remove risk of load tipping, sliding, or bending
And?
Remove the possibility of low sling angle
85
When using double basket hitch never incline the legs less than _____ degrees?
60 degrees
Lower degrees will result in sling pulling toward eachother under load
86
When is a double basket hitch used?
When loose pieces need to be secured together
87
What is better double wrap choker hitch or double wrap basket hitch
Double wrap basket which will not reduce the swl as much as a double wrap choker hitch
88
A knot reduces breaking strength of a rope by ______% cable clips installed correctly reduce breaking strength by ______%
50
20
89
To figure out SWL of a basket hitch?
90
When calculating weight of material you need the volume x ______ of material
Approximate weight
Steel 500 lbf per cubic foot
Wood 35 lbf per cubic foot
Concrete 150 lbf per cubic foot
91
If the shape of the material to be hoisted is hard to measure what should you do?
Just make it into a measurable shape, square or rectangle. Piece will measure out heavier then it actually is which will create a better safety factor
92
Never run fibre ropes over sheaves that have been used for wire ropes. How come?
Rapid rope damage will occur
93
What is the difference between the travelling block and the standing block?
Travelling or fall block is attatched to the load being lifted or moved. It moves with the load
Standing block takes the load and is stationary
94
How do you calculate mechanical advantage on blocks?
Count the amount of ropes on the traveling blocks
95
Angles for snatch blocks reduce similarity to rigging angles. True or false
True
96
Angles for snatch blocks reduce similarity to rigging angles. True or false
True
97
Before moving a load always consider the following factors?
-characteristics of load(weight, shape etc)
- present location
- location to be moved
- equipment available
- safety precautions which have to be in place before the move
And
The path of the move
98
Stop
99
Hoist load slowly
100
Hoist load
101
Lower load
102
Travel
103
Dog everything
104
Number 1 grade Manila is the only synthetic rope used for ?
Sturdy enough for lifting
105
Nylon rope has the ________ ? 2 1/2 times that of Manila.
Greatest strength
106
Nylon rope is resistant to:
Abrasion
Organic solvents and alkalis
Moisture and rot
107
Strength reduction for rope
108
Calculate weight of a steel ring?
Outside diameter minus inside diameter
109
When does the operator need a signalman?
-operator cannot see the load or landing area
- the distance between the load and operator is great enough that it is difficult for the operator to judge the distance
- the crane is within a booms length of electical lines
- operator does not have a clear view of the path to be taken
110
Signal man should:
Have a clear view of the operator
Have a clear view of the objects and it’s path
Stay out of the objects travel
111
Signal for emergency stop
112
Standard movement signals
113
Commands for lowering boom and raising the load or raising the boom and lower the load.
114
Telescoping boom signals
115
Who should know the safe working loads of the equipment and hardware?
The person doing the rigging
116
What does the safety factor take into account?
SWL is determined on a basis of a static load.
The safety factor takes into account slight dynamic loads
117
When calculating multiple sling legs it is important to only use 2 of them. How come?
It is impossible to say how much load each sling is taking. On a 4 leg lift usually 2 are caring the load and the other 2 are balancing the load
118
When do you need to use a shackle?
When two or more sling eyes are placed in the hook
119
Weight per cubic foot of steel and equation to figure out weight of an steel plate? 4’ x 8’ x 1/2”
490 lbs cubic foot of steel
Volume = L x H x W
First get everything into the same measurements. 05/12= .0417’
V = 4 x 8 x 0.0417 = 1.3344 cubic feet
1.3344 x density of steel 490 = 653 lbf
120
Weight per cubic foot of aluminum?
165 cubic foot
121
One cubic foot of concrete is
150 lb per cubic foot
150 x 27 = cubic yard weight
122
Conversions cubic pounds to metric
123
Cubic foot of steel equals 490 lbs
How much does 1 square foot 1” thick weigh? 490 / 12 = 40.9 now how much does it way per 8ths
40.9 / 8 = 5.1125 lbs
With this formula you can easily figure out weight of any steel plate.
Area = length x width
Area x weight per 8th
7/8 plate would = 7 x 5 = 35lbs
4 X 8 = 32 x 35 = 1120 pounds
124
What is the equation to figure out weight of steel pipe?
3.14 x length x wall thickness x ( diameter - wall thickness)
125
As a crane rigger or signaller you must be able to perform the following tasks:
- establish or calculate the weight of the load and rigging.
- judge distance, heights and clearances
- select tackle and hardware suitable to the load
- rig the load safely And secure it to the crane hook
- be fully confident and adept with hand or voice radio signals
- maintain communications with crane operator
- direct the crane movements to pick up and place the load
- assist with crane positioning and set up
- communicate with other workers about how the lift is planed
- manage the safety of others around the lift zone
- recognize the factors that reduce the cranes capacity
126
What forces come into play when determining ground stability for a crane?
- crane weight
- weight of the load and rigging
- any dynamic forces set up by the machine
- vibrations in moving the load
127
When should you be extra careful when looking for good ground to set up crane?
Freshly disturbed soil:
- sides of new buildings
- embankments
- underground electrical or sewer lines
128
Outrigger floats are?
Usually wood placed under the floats to increase the support area.
Must always be used
129
What is used to level a crane after initial leveling with the cranes target level?
4’ carpenters level
130
When using crane outrigger load charts, you must correctly set up the outriggers. If you do not properly set up the outriggers you have to use ________ chart?
On rubber (tires)
131
What is the tipping point of a crane?
Point at the crane to ground contact base where the crane tips. In a lever this is called the fulcrum.
132
What is the difference between crane centre of gravity and load centre of gravity?
Crane centre of gravity is the point in the crane body from which the weight acts.
Load centre of gravity is the point in the load where the weight is concentrated
133
What is load leverage?
Combined values of the load weight and the distance between tipping point and load centre of gravity
134
What is the most dangerous position of the boom?
When lifting directly over one outrigger over the corner.
135
Factors that reduce capacity of a crane?
- machine configuration not to specifications
- poor machine condition
- unbalanced or eccentric reeving ( how the cable is threaded through through pulley blocks
136
Setup factors reducing cranes capacity:
- soft footing
- unstable or loose substrate
- improper setup of outriggers
- crane not level
- crane proximity to structures
137
Hoisting or rigging operations factor that reduce crane capacity?
- load stability
- increased load radius
- side loading
- rapid swing rate
- impact loading with rapid acceleration and deceleration of the load
138
Environmental factors that reduce crane capacity?
Power lines
- wind conditions
- other workers moving through hoisting zone
Stop operations in windy conditions
139
What is minimum limit to approach with a crane near a power line up to 50 kilo bolts?
10 feet
140
Where must the load chart be placed in a crane?
Secured inside the crane cab where it can easily be read but not removed
141
Equation for calculating crane net capacity?
142
EOT stands for?
Electric overhead travelling crane
