Introduction to - SaskPower 1 Book 2/13...give you sufficient mechanical advantage in these lifting and pulling tasks. In this module, you will learn about the advantages of a block

�T R A I N I N G

M A N U A L1 2 / 1 7 / 9 8

Introduction toTensioning

Tools

Training Development Centre

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II N T R O D U C T I O N T O

T E N S I O N I N G

T O O L S

OBJECTIVE:Given a ratchet hoist or block andtackle, as well as wire grips, you will beable to explain and/or demonstrate theuse and maintenance of line tensioningtools.

WHY?As a lineman, it is important to know theproper use of all tools and equipment used inthe line trade for your safety and that of othersaround you.

LEARNING OBJECTIVES:1. Explain the use and maintenance of

ratchet hoists.

2. Explain the use and maintenance of ablock and tackle.

3. Assemble a block and tackle.

4. Identify the position and MA of the blockand tackle.

5. Calculate the tension on the fall line of ablock and tackle.

6. Identify the three main types of grips.

7. Describe the four types of grip jaws, theirapplication and maintenance.

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Digger Derrick

Basic Electricity

Safety

Line Design & Construction

Tools

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Copyright © 1997 by the Training and Development Centre, SaskPower. All rights reserved. 1 2 / 1 7 / 9 8

IN THIS MODULE:1. Ratchet Hoist

2. Block and Tackle

3. Power Line Grips

RESOURCES:• Ratchet Hoist

• Block and Tackle

• Grips

• Lineman Information Manual

• Introduction to Tensioning Tools Video

ESTIMATED TIME:1/2 hour

PREREQUISITES:• Safety Manual module

LEARNING STEPS:1. Cover the module.

2. Complete the Review Questions.

3. Clarify any questions you may have.

4. Complete the Skills Practice.

Copyright © 1997 by the Training and Development Centre, SaskPower. All rights reserved.1 2 / 1 7 / 9 8

IntroductionA good portion of power line work involves heavy lifting and thetensioning of wires. This can be made easier using tools whichgive you sufficient mechanical advantage in these lifting andpulling tasks.

In this module, you will learn about the advantages of a block andtackle for heavy lifting, a ratchet hoist for tensioning a wire, and avariety of cable grips which can be attached to the wire beingtensioned.

Ratchet Hoist

Chain housing

The ratchet hoist must be kept clean for efficiency. Check thechain condition for damage and excessive wear, making sure itwill move through the pulley without binding.

1-ton ratchet hoist

4 T R A I N I N G M A N U A L .

1 2 / 1 7 / 9 8Copyright © 1997 by the Training and Development Centre, SaskPower. All rights reserved.

The centre bearing must rotate freely. Clean all moving parts andlubricate with light oil or graphite. Clean the chain and wipe theentire tool with a cloth. Store in a dry area.

The ratchet hoist, used for tensioning wires, is available in varioussizes, depending on the pulling strength required. It is used withvarious sizes of line grips which match the conductor beingtensioned.

Tongue in the “Up”position

When the load is left connected under tension, thehoist must be placed in the “Up” position.STOP

For added security, use of the locking latches locatedon each hook is mandatory. Never over-extend therated load capacity of the ratchet hoist or the gripbeing used. When operating the ratchet hoist, makeyour motions smooth.

!

I N T R O D U C T I O N T O T E N S I O N I N G T O O L S 5 .

1 2 / 1 7 / 9 8 Copyright © 1997 by the Training and Development Centre, SaskPower. All rights reserved.

Block and Tackle

The block and tackle can be used for lifting materials or thetensioning of wires. They come in various sizes. The mechanicaladvantage is directly proportional to the number of ropessupporting the load.

This will ensure that the rope size will be compatible with thesheave size. In this example, we are using a 4 inch shell, and a 1/2inch rope.

4 inch shell and 1/2inch rope

On wood blocks, allow 1 inch of shell for every 1/8 inch of ropediameter.

4-sheave block andtackle



Procedure for Threading the Block and TackleThe following explains the procedure for threading the block andtackle:

• First, secure the blocks on a flat surface.

• The becket block has the becket, and the other block shouldbe set on its edge.

• Always begin on the block with the becket.

• Begin threading at the sheave adjacent to the becket.

• Enter the sheave locations corresponding to where the ropeexits.

• Tie a bowline knot through the thimble located on thebecket.

• Now is a good time to examine your work. There should bea clear path, both horizontally and vertically, between theropes.

The rope blocks can be utilized in two operating configurations.One is the standing position, in which the block with the fall lineremains stationary. There are four ropes supporting the weight inthe standing position.

Standing position:four ropes

supporting the load



The other configuration is the running position, in which the blockwith the fall line travels with the load. There are five ropessupporting the weight in the running position.

Calculating Tension on Fall LineThe tension on the fall line is calculated by adding the weight ofthe object to be lifted, plus the friction of the sheaves, divided bythe mechanical advantage.

WeightDetermine the weight to be lifted. Our example is 200 pounds.

FrictionEach sheave generates friction amounting to 10% of the weight. Inour example, the loaded weight is 200 pounds and we are using afour sheave block and tackle. (200 pounds multiplied by 10%equals 20 pounds of friction per sheave multiplied by four sheavesequals 80 pounds of total pressure.)

In general, the running configuration requires less effort to movethe weight.

Running position:five ropes supporting

the load



Mechanical AdvantageThe mechanical advantage is determined by the number of movingropes supporting the load.

In the standing position, you have four ropes supporting the load;therefore, the mechanical advantage is 4. In the running position,there are five ropes supporting the load; therefore, the mechanicaladvantage to be used in the calculation is 5.

TensionTension is the amount of force required on the fall line to move theweight.

The calculation in the standing position is: 200 pounds of weightplus 80 pounds of friction, divided by a mechanical advantage of 4.This equals 70 pounds of tension on the fall line with the block andtackle in the standing position.

The calculation in the running position is: 200 pounds of weightplus 80 pounds of friction, divided by a mechanical advantage of 5.This equals 56 pounds of tension on the fall line with the block andtackle in the running position.

Storage of Block and TackleWhen storing the block and tackle, hold the blocks together withthe rope and slip a half-hitch over one block. Wrap the excess ropeinto a hand coil and secure.

Because the rope and blocks are perishable, they should be hungup during storage in a clean, dry location to prevent weathering.



Power Line Grips

There are two main types of power line grips used by linemen.These tools are sturdy and easy to use. However, they must bemaintained and kept in good working condition.

In all cases, the maintenance requires an inspection of the grip.

Maintain gripsmeticulously

Use a solvent and wire brush to clean the gripping surface toprevent slippage.

Chicago grips



The jaw configurations on the various gripping surfaces are either:

• two oval-shaped jaws for use on large diameter conductor

• two triangle jaws for high strength cable

Double”V” grip

Round grip

Lubricate with drygraphite

The jaws must be clean and move smoothly. Use a light oil orgraphite to keep all the parts moving freely.



• a grip with one oval and one serrated jaw for coatedconductor

• a grip that has one triangle and one flat jaw for bare wire

Chicago Grips

Chicago grips are the most commonly used, and they are availablein various sizes and jaw patterns. The parallel grooves on the jawsare designed to prevent damage to the conductor. The jaws closewhen pressure is applied to the pulling eye of the grip ensuring atight fit on the conductor.

Chicago grips willlock open using the

moving handle

Please refer to the conductor data section in the ConstructionStandards Manual, and the grip manufacturer’s specifications,to select the appropriate grip for the job.

Single “V” grip



Hot Line Grips

Hot line grips are similar to Chicago grips with a few variations indesign. The jaws are made in triangle and oval contours only. Hotline grips have a safety gate to prevent the grip from falling off theconductor. The gate also holds the grip parallel on the conductorso that it may be installed easily with the aid of a hotstick.

Haven Grips

Haven grips are sometimes called a “bulldog grip.” This type ofgrip is eccentric, which prevents slippage. As the hook is pulledon with force, the grip rolls somewhat and tightens up.

This type of grip should not be used as it is an olderstyle and tends to damage the conductor.!

Haven (bulldog)grips should not be

used

Hot line grips have asafety gate



SummaryTo summarize this module, you have learned:

• The use and maintenance of line tensioning tools.

• The assembly of a block and tackle.

• How to calculate the tension on a fall line.

• The main types of grips used in the line trade.

Now...

• Complete the Review Questions.

• Clarify any concerns or questions you may have.

• Complete the Skills Practice.



REVIEW QUESTIONS

Use and Care of Tensioning Tools

Explain the use and maintenance of ratchethoists.

1. Listed below are some maintenance and operating practises.Circle the statements that are best suited to a ratchet hoist. (Youmay choose more than one.)

(a) Never use a snipe to gain a mechanical advantage.

(b) Safety latches on the hooks should be used for added security.

(c) Leave the ratchet hoist in the “Up” position when a load isleft under tension.

(d) The hooks must always have a grip connected to it when inuse.

(e) Lubricate center bearing and the chain housing with graphite.

(f) Use smooth motions to avoid shearing a pin off internally.

This section is a review for your Power Line Apprenticeshipwritten exams. Complete the questions, and verify your answerswith the Review Question Solutions located at the end of thismodule.



Explain the use and maintenance of a blockand tackle.

2. Listed below are some maintenance and operating practises.Circle the statements that are best suited to a block and tackle.(You may choose more than one.)

(a) The mechanical advantage is always one more than thenumber of ropes.

(b) Allow 1/8 inch of rope for every 1 inch of shell.

(c) Hanging is not required to preserve wood and rope.

(d) Abuse could lead to broken blocks.

(e) Tie together and hang for storage.

Identify the position and MA of the block andtackle.

3. Label the following graphics as to their operating position andstate the mechanical advantage.

(a)

Position: ____________________

MA: _________

(b)

Position: ____________________

MA: _________



(c)

Position: _____________ ____________ ___________

MA: _____ _____ _____

(d) What would the MA be if the positions were opposite to thoseshown in the graphics of (c) above?

MA: _____ _____ _____

Calculate the tension on the fall line of ablock and tackle.

4. If the weight being lifted was 200 lbs., what is the tension on thefall line in each of the examples shown in Question #3 above?

(a)

(b)

(c)

(d)



Identify the three main types of grips.

5. Identify each of the grips pictured below by matching the gripname with the graphic.

(a) Chicago grip

(b) Haven grip

(c) Hot line grip

_____

_____

_____



Describe the four types of grip jaws, theirapplication and maintenance.

6. Match the appropriate grip jaw from the left column to theapplication in the right column.

T / F 7. To prevent a grip from slipping, use the grip for its designedapplication and wire brush the jaws using solvent to remove anyunwanted material.

T / F 8. Before tension is applied to a Chicago grip, the jaws should beperpendicular to each other.

9. State the correct practise to follow when working with a damagedgrip.

___ Coated conductor

___ Bare wire

___ Large diameter ACSR

___ High strength cable

(a) Oval

(b) Triangle

(c) Serrated

(d) 1/2 Triangle,

1/2 Flat-sided



SKILLS PRACTICE

Introduction to Tensioning Tools

Assemble a block and tackle.

1. Set blocks for threading.

___ Place blocks 90 degrees to each other.

___ Secure ends.

___ Becket on the bottom generally best.

2. Thread blocks.

___ Begin at sheave adjacent to becket.

___ Enter the next sheave location corresponding to where therope exits.

___ Tie a bowline at the becket.

___ No crosses in the rope.

3. Storage.

___ Pull blocks together.

___ Tie half-hitch over blocks.

___ Wrap excess rope in hand coil.

___ Store hanging up, out of the sun and weather.

This section is intended as a practice for your Power LineApprenticeship practical exams. Perform each task, asdescribed, under the direction and observation of a competentperson. They should complete the checklist and give youappropriate feedback.



1. a, b, c, e, f

2. b, d, e

3. (a) Standing, 4

(b) Running, 5

(c) Running, 3Standing, 4Standing, 6

(d) 4, 5, 7

4. (a) 70 lbs.

(b) 56 lbs.

(c) 86.6 lbs., 70 lbs.,53.3 lbs.

(d) 65 lbs., 56 lbs.,45.7 lbs.

5. a, b, c

6. c, d, a, b

7. True

8. False

9. Don’t use it, send it in forrepair or replacement


REVIEW QUESTION SOLUTIONS

Introduction to Tensioning Tools




Documents

Introduction to - SaskPower 1 Book 2/13...give you sufficient mechanical advantage in these lifting and pulling tasks. In this module, you will learn about the advantages of a block