1. BOLTED JOINT ASSEMBLY WIND ENERGY FIELD SERVICE TECHNICIANS
TOOL OPERATION AND HANDLING
This presentation reviews the most common and effective bolting tool options for wind energy installation and maintenance activities
© HYTORC 2009

2. SAFE Tool Operation & Handling
The following material is intended to make you aware of the commonly accepted and recognized principles and methods used in assembling bolted joints. However, every possible application of these methods cannot be foreseen and these general guidelines do not supersede any other applicable rules or regulations.
ALWAYS FOLLOW CURRENT COMPANY AND LOCAL SAFETY RULES AND PROCEDURES WHEN PERFORMING ANY OF THE WORK DESCRIBED IN THIS PRESENTATION.
The authors and sponsors of this course have no control over, and assume no responsibility for any damage, injury or work interruptions due to any person’s use of, or reliance upon these generally accepted methods and principles.
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No course can cover all possibilities and address all problems. The key is to know what to look for, and where to go to get the answers.
Hopefully that is what you will take away from this course.
SAFE Tool Operation & Handling
© HYTORC 2009

3. TODAY’S WIND TECHNICIAN WEARS MANY HATS
Today’s bolting professional wears many hats.
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on any given day he may find him self in the middle of an overhaul on many different kinds of equipment
AND WORKS IN SOME CHALLENGING PLACES
© HYTORC 2009

4. BOLTING REQUIRES POWERFUL TOOLS
JUST ONE 56MM BASE BOLT CARRIES A LOAD OF MORE THAN…
200,000 POUNDS!
2-1/2
THAT’S EQUAL TO THE WEIGHT OF 2-1/2 FULLY LOADED TRACTOR TRAILERS ON ONE BOLT!
The forces associated with tightening bolted joints are impressive and we often take them for granted because in general modern bolting tools are extremely strong and safe.
For example, a single properly tightened 56mm tower base bolt carries a clamping load of MORE THAN 200,000 POUNDS. Since a fully loaded tractor-trailer on the highway weighs about 80,000 pounds, that means that one single bolt is carrying more than the weight of 2-1/2 big rigs! Imagine the power it takes to create that kind of load.
SAFE Tool Operation & Handling
© HYTORC 2009

5. HERE’S ONE WAY TO DO IT IF YOU ARE JUST HANGING AROUND
HOW CAN WE GENERATE SUCH FORCES?
How can we generate such huge forces?
Well, here is one way if you are just hanging around. Since torque is defined as an applied force at a measured distance from the center axis, you can get more torque by using a longer lever (greater distance)
HERE’S ONE WAY TO DO IT IF YOU ARE JUST HANGING AROUND
GET A LONGER LEVER…
© HYTORC 2009

6. And here’s another if you need to hammer out your frustrations!
…or a bigger hammer (more force).
I knew some mechanics who swore they could tell by the sound of the ring of the hammer wrench when everything was just right!
Obviously there has to be a better way, and there is.
…OR A BIGGER HAMMER
© HYTORC 2009

7. TOOLS FOR BOTH POWER AND CONTROL
GENERALLY FOR BOLTS SMALLER THAN 1” DIA.
WITH EXCEPTIONS
MANUAL TORQUE TOOLS
PNEUMATIC TOOLS
GENERALLY FOR BOLTS LARGER THAN 1”DIA.
HYDRAULIC WRENCHES
It is not enough to just get things tight – they have to be right!
Lets review the kinds of tools that can give us this both power and control.
We will briefly become acquainted with 4 categories of bolting tools:
MANUAL TORQUE TOOLS (these fall into two types, torque wrenches and torque multipliers)
PNEUMATIC TOOLS (we could also include some electric tools here but they are not generally applied in the wind business)
THESE TOOLS ARE GENERALLY USED ON “SMALLER” FASTENERS (LESS THAN 1” DIAMETER) ALTHOUGH THERE ARE EXCEPTIONS
HYDRAULIC WRENCHES (both square drive and low profile types)
And
TENSIONERS (both hydraulic and mechanical)
THESE TOOLS ARE GENERALLY USED ON “LARGER” FASTENERS (GREATER THAN 1” DIAMETER)
Let’s take a closer look at each kind of tool.
TENSIONERS
© HYTORC 2009

8. 2 BASIC KINDS OF MANUAL TORQUE TOOLS..
Torque wrenches
When we talk about manual or hand operated tools for industrial bolting we mean either torque wrenches or torque multipliers
Hand torque wrenches directly measure the turning force applied to a bolt on some form of scale, dial, or display and often have a limiting device or indicator alarm to ensure accuracy and control.
Hand torque wrenches are usually sufficient to achieve the desired torque and load on bolts up to about ¾” in diameter.
Manual torque multipliers When torque requirements are more than can comfortably be obtained by using a simple wrench a device called a torque multiplier is sometimes used. It is a socket style ratcheting wrench which incorporates a set of planetary gears which “multiply” the input force applied at the handle, through a set of planetary gears and out to the square drive. They are usually classified by their input to output ratio such as 18:1, meaning that it would take 18 turns of the input handle to generate 1 turn of the output socket but the socket will apply 18 times the input force. These tools can be very useful for small jobs but are not practical for many bolts or reduced spaces. Care must be taken to avoid backlash in the handle under load.
Torque multipliers
MANUAL TORQUE TOOLS
© HYTORC 2009

9. MANUAL TORQUE WRENCHES
4 BASIC TYPES
MANUAL TORQUE WRENCHES
DEFLECTING BEAM
SENSITIVE CALIBRATED INSTRUMENTS
PROTECT FROM DAMAGE AND ABUSE
FOLLOW OPERATING INSTRUCTIONS
CONSISTENT STEADY PULL –
NO JERKS ALLOWED!
ADJUSTABLE CLICK TYPE
Manual torque wrenches:
There are four basic types of manual torque wrenches which are worth mentioning here:
DEFLECTING BEAM
ADJUSTABLE CLICKER
DIAL INDICATOR
DIGITAL AND EVEN PROGRAMMABLE ELECTRONIC
All of these tools are sensitive calibrated instruments which must be protected from damage and abuse and carefully handled and stored if they are to give accurate results. For example, these tools should not be used to break loose stubborn fasteners or for general tightening when torque control is not necessary. When applying torque to a fastener, the wrench should be pulled, not pushed. Pulling provides for greater control. Always pull with a slow, steady force in a perpendicular direction. Jerky uneven turning will not produce accurate and repeatable results. “Cheater bars” or other non-authorized extensions should never be attached to a torque wrench as serious damage could result.
The hand that is not pulling on the wrench should be located directly over the point of rotation to provide support.
DIAL TYPE
DIGITAL ELECTRONIC
MANUAL TORQUE TOOLS
MANUAL TORQUE TOOLS
© HYTORC 2009

10. MANUAL TORQUE TOOLS MANUAL TORQUE TOOLS ¼”, 3/8,”, ½” DRIVES
DEFLECTING BEAM
¼”, 3/8,”, ½” DRIVES
SIMPLE, LIGHT DUTY
SCALE READING IS OPERATOR DEPENDENT
¼”, 3/8,”, ½”, ¾” DRIVES
SELF LIMITING, VERSATILE
REGULAR RE-CALIBRATION
STORE WITH MINIMAL TENSION ON SPRING
The deflecting beam is the simplest of all the torque wrenches in that it does not rely on complicated settings or indicators. It shows torque in either direction on a simple scale and except for extreme abuse is “recalibrated” simply by bending the needle to “0” before use.
The reading of the scale is operator dependent and subject to parallax. This type of wrench is generally limited to small light duty jobs. Since there is no automatic limiting mechanism, consistency from bolt to bolt is highly operator dependent.
The micrometer or “clicker” type wrench has the advantage of automatically limiting the torque output of the tool because the ratchet will slip and “click” when the desired value is reached. Large models with output up to about 600 ft/lbs are available as well as smaller sizes. When using a “clicker” type wrench, always adjust the setting in the increasing direction. If you wish to go to a lower setting, adjust the dial to well below the setting and then tighten back to it. Wrenches should be stored with no more than about 10-20% of their maximum value set on the micrometer. More than that could affect the internal springs. As with all torque wrenches, these should be re-calibrated periodically. This must be done by a qualified technician with the appropriate testing equipment and tooling.
ADJUSTABLE CLICK TYPE
MANUAL TORQUE TOOLS
MANUAL TORQUE TOOLS
© HYTORC 2009

11. MANUAL TORQUE TOOLS MANUAL TORQUE TOOLS ¼”, 3/8,”, ½”, ¾” DRIVES
EASY READ MICROMETER SCALE
EASY RE-CALIBRATION
NEEDLE CAN RECORD ACHEIVED TORQUE VALUE
DIAL INDICATOR
¼”, 3/8,”, ½”, ¾” DRIVES
PROGRAMMABLE & DIGITAL
TORQUE AND ANGLE
RECORDING AND PRINTING
VISUAL, AUDIBLE AND “FEEL” INDICATORS
Dial indicator wrenches come with various features but their main advantage is the accuracy of the dial readout and the ease with which that can be re-set to a zero start. Some feature a “follower” needle which records the maximum torque applied during that tightening. Recalibration of the spring mechanism should be done periodically.
The newest, and by far the most versatile torque systems are the digital electronic models which incorporate a programmable computer chip and even feature the ability to record, store and print out a series of tightenings.
The digital display eliminates the guesswork of reading a scale or dial. Variable target torque settings allow consistent control without operator guesswork. Values can be shown for inch/pounds, foot/pounds, or Newton/meters as required.
Visual, audible and even vibration alarms are included.
There are even settings which measure a base torque combined with an angle of turn indicator and alarm.
Let’s view a short summary of some of the most advanced features.
DIGITAL ELECTRONIC
MANUAL TORQUE TOOLS
MANUAL TORQUE TOOLS
© HYTORC 2009

12. MANUAL TORQUE TOOLS DIGITAL ELECTRONIC
(Movie clip of electronic torque wrench features)
MANUAL TORQUE TOOLS
© HYTORC 2009

13. MANUAL TORQUE MULTIPLIERS
SPECIFIC INPUT TO OUTPUT RATIO
PLANETARY GEARS
NEWEST HAVE DIGITAL READOUT
As we said before, multipliers extend the range of the simple torque wrench by passing the measured input forces through a gear set that amplifies the output torque.
The most common style is the handle with a micrometer “click” setting but newer digital models offer greater flexibility and accuracy. We will see and use some of these tools during our hands-on exercises.
MANUAL TORQUE TOOLS
MANUAL TORQUE TOOLS
© HYTORC 2009

14. BUT DO NOT MEASURE TORQUE CONTROLLED CALIBRATED TORQUE
Impact wrenches
Excellent at producing torque
BUT DO NOT MEASURE TORQUE
Pneumatic wrenches
Air tools used in bolting are of two types: impact wrenches and air-driven multipliers.
Impact wrenches have been used for many years in all types of bolting. Their main advantages are 1) speed of run-down and 2) high shock and vibration as an aid in breaking loose a stubborn bolt. Other than for those two purposes impact wrenches have no place in precision industrial bolting. Not only are they not regulated for output but the noise and vibration associated with them can raise safety concerns.
Air-driven multipliers function in much the same way as the hand torque multiplier in that they magnify the input force through a set of gears to give a greater output torque. The difference is that rather than rely on manual effort, the gears are driven by an air motor. Recent models of this type of tool are very accurate and simple to use and can produce excellent results. There are even battery powered models driven by electric motors rather than air. The battery driven tools are very portable but battery life concerns limit their usefulness. Electric DC or modulated AC systems are available but have not been useful in field conditions.
The most advanced air multiplier on the market features dual speeds and shifts from fast-run down, to calibrated torque power with the same tool. Here is how it works.
(demo of Flip Gun)
Air multipliers
CONTROLLED CALIBRATED TORQUE
PNEUMATIC TOOLS
© HYTORC 2009

15. HYDRAULIC WRENCHES POWER IN A SMALL SIZE
PRECISE CONTROL AND REPEATABILITY
VERSATILITY
For larger bolts, of about 1” diameter and more, the most versatile, powerful and safe tool is unquestionably the hydraulic wrench.
These proven tools provide tremendous power in a small package, precise control and repeatability from bolt to bolt to bolt, and are extremely versatile.
HYDRAULIC WRENCHES
© HYTORC 2009

16. ALL HYDRAULIC WRENCHES PRODUCE POWER IN A SIMILAR WAY
PUMP
PISTON
POUNDS OF FORCE
Apply a measured pressure in pounds per square inch (p.s.i)
To a piston of known area (square inches)
And you can predict the output (pounds)
Let’s review the basics:
All hydraulic wrenches work on the same basic principles.
If we apply a known pressure (oil pressure measured in “pounds per square inch” over a known area (the end of a piston measured in “square inches”
Then we can know the amount of “pounds” of force coming out the drive of the wrench.
Therefore the output of the wrench is regulated by adjusting the pressure on the pump. Since hydraulic fluid is non-compressible, the transfer of pressure to power is seamless, predictable and uniform.
HYDRAULIC WRENCHES
© HYTORC 2009

17. Square drive socket style wrench with adjustable reaction arm
2 BASIC STYLES
Square drive socket style wrench with adjustable reaction arm
Low Profile narrow clearance wrench with interchangeable ratcheting links
Hydraulic wrenches
The tools contains a hydraulic cylinder which acts like a jack, a drive to engage the nut or bolt, a ratcheting mechanism to allow the drive to reset and a reaction arm to block the tool from turning. They are powered by an external hydraulic pump with variable pressure. Each tool has a known relationship (as shown on a pressure/torque conversion chart) between the desired torque and the required pressure on the pump. Set the pressure and you get the desired torque, no more and no less, subject to the effects of friction and other external factors.
Hydraulic wrenches come in many variations on two basic styles The most common are those which have a square drive and use standard impact sockets. The advantage of these tools is that it is simple and inexpensive to change to a different size nut by changing the socket. (These powerful tools must be used only with high quality impact grade sockets, never with a chrome socket or sockets meant for hand tools!) We will discuss more about socket safety later on.
The second type uses special in-line link sockets to reach into reduced spaces or to pass down over a long stud to reach nut.
Hydraulic wrenches come in many different sizes depending on the torque requirements of the job. Each size has a range of torque values. The largest wrenches may tighten nuts larger than 6” across the flats to more than 50,000 ft/lbs. Often such power is needed to remove a nut or bolt that has been in place for a long time, especially if it has been subject to corrosion or high heat. (for a more complete discussion of hydraulic wrenches and their capabilities see
HYDRAULIC WRENCHES
© HYTORC 2009

18. SQUARE DRIVE WRENCH FEATURES
USES IMPACT SOCKETS – EASY TO CHANGE BOLT SIZES
REVERSE DRIVE TO REVERSE TOOL FOR ON OR OFF
ADJUSTABLE REACTION ARMS AND ACCESSORIES
SIZE RANGES UP TO 130,000 FT/LBS (TOOL NUMBER INDICATES MAX TORQUE OF TOOL AT 10K P.S.I.)
EXAMPLE OF TOOL NUMBERING
AVANTI-3 APPROX FT/LBS MAX
AVANTI-10 APPROX. 10,000 FT/LBS MAX
Square-drive wrenches:
use impact sockets so it is easy and inexpensive to change nut sizes
They are both for tightening and for break out of bolts
Many accessories are available which adapt the basic tool to special applications
Sizes range from 30 ft/lbs up to 130,000 ft/lbs with drives from ½” up to 3-1/2”
Square-drive wrenches are numbered according to their approximate maximum torque output at the maximim pump pressure of 10,000 psi. (for example a Hytorc Avanti-3 has a maximum torque of approximately 3000 ft/lbs at 10,000 psi pump pressure, while and Avanti-10 will produce about 10,000 ft/lbs at that same pressure)
HYDRAULIC WRENCHES
© HYTORC 2009

19. LOW PROFILE WRENCH FEATURES
INTERCHANGEABLE RATCHETING LINKS
FITS IN TIGHT PLACES AND OVER LONG STUDS
ACCESSORIES GIVE GREATER VERSATILITY
SIZE RANGES UP TO 130,000 FT/LBS (TOOL NUMBER INDICATES MAX TORQUE OF TOOL AT 10K P.S.I.)
EXAMPLE OF TOOL NUMBERING
STEALTH-4 APPROX FT/LBS MAX
STEALTH-14 APPROX. 14,000 FT/LBS MAX
Low-profile or narrow clearance wrenches
Instead of using impact sockets, these employ interchangeable ratcheting links (each with a broad range of socket sizes for each size of wrench)
Which fit into tight overhead clearance place or over long protruding studs where a socket can’t fit
Many accessories enhance the versatility of these tools and
They are available for nut sizes from ¾” up to 6-1/8th inches, and they are numbered according to their nominal toque output at 10,000 psi.
HYDRAULIC WRENCHES
© HYTORC 2009

20. CHOOSING THE “RIGHT” TOOL FOR THE JOB
DOES THE TOOL FIT?
RIGHT STYLE (SOCKET OR NARROW CLEARANCE)?
WILL IT PROPERLY ENGAGE THE NUT TO TIGHTEN AND LOOSEN?
IS THERE SUFFICIENT RADIAL AND OVERHEAD SPACE?
WILL IT REACT FIRMLY AND SAFELY?
DOES THE TOOL NEED SPECIAL SUPPORT OR MODIFICATIONS?
ARE THE HOSES AND CONNECTORS FREE FROM BINDING?
CAN I USE MULTIPLE TOOLS AT THE SAME TIME?
DOES IT HAVE ENOUGH POWER?
WHAT IS THE RANGE OF THE TOOL?
TOP REQUIRED TORQUE SHOULD BE 60-75% OF TOOL CAPACITY
AM I USING THE TOOL TO ITS MAXIMUM TORQUE?
CAN I BREAK LOOSE WITH THIS SAME TOOL?
AM I USING TOO LARGE A TOOL WHEN A SMALLER ONE WILL DO?
Choosing the “right tool for the job” is a matter of “FIT” and “POWER”
(read the slide)
HYDRAULIC WRENCHES
© HYTORC 2009

21. CHOOSING THE “RIGHT” PUMP FOR THE JOB
ELECTRIC VS. AIR?
FLAMMABLE OR EXPLOSIVE ATMOSPHERE?
AVAILABILTY OF AIR (100 p.s.i. & 50 c.f.m., ¾” hose)?
AVAILABILITY OF POWER (120V 20 AMPS at the pump)?
DISTANCE FROM THE AIR OR POWER OUTLET?
DOES PUMP HAVE ENOUGH CAPACITY?
HOW MANY TOOLS OF WHAT SIZE WILL RUN?
MULTIPLE PORTS TO SUPPORT MULTIPLE TOOLS?
PRESSURE RANGE 0-10,000 P.S.I.
SPEED IS A FUNCTION OF FLOW, NOT PRESSURE
SMALL (200 cu.in./min) STANDARD (700 cu.in./min) LARGE (1500 cu.in./min)
IS PUMP LIGHT AND MOBILE ENOUGH?
SMALL (30 lbs.) STANDARD (50 lbs.) LARGE (100 lbs.)
Hydraulic pumps come in many variations on two basic power sources:
Electric powered and Air powered.
In the wind industry the vast majority of pumps are powered by electric motors due to the difficulty of providing sufficient air to remote locations and up the towers. We will review pumps in greater detail later.
(Read the slide)
HYDRAULIC WRENCHES
© HYTORC 2009

22. MECHANICAL TENSIONERS
TOOLS THAT TENSION
TENSIONING APPLIES LOAD THROUGH DIRECT ELONGATION OF A STUD
HYDRAULIC TENSIONERS
MECHANICAL TENSIONERS
We have looked at torque as one way of putting load into a bolt. But there are other ways including stretching the bolt with direct tension. In general tensioning has the advantage of eliminating torsion in the bolt as well as associated lateral and bending forces and it does away with the concern for friction that has such an effect on the relationship between torque and load. But tensioning also has limitations and some disadvantages which must be understood and dealt with if they are to be used effectively and safely.
There are various kinds of tensioning devices but here we will examine the two most common types:
Hydraulic tensioners
Mechanical tensioners
Let’s first discuss hydraulic tensioners and how they
TENSIONERS
© HYTORC 2009

23. Introduction to Tensioning
2. Tension Applied to Bolt
1. Untightened State
3. Nut Rotated onto the Joint
4. Tightened Joint
The diagrams show the sequence involved when a bolt is tightened by tensioning.
1. Prior to tensioning the nuts are placed onto the bolt so that they are in contact with the joint faces.
2. Tension is applied to the bolt so that there is a gap between the nut and the joint face.
3. With the tension still applied the nut is rotated so that it is in contact again with the joint face.
4. The tension is then removed from the bolt so that the load is carried by the nut.
HYDRAULIC TENSIONERS
© HYTORC 2009

24. The Hydraulic Tensioner
1. STRETCH THE STUD
2. TIGHTEN THE NUT
3. RELEASE THE STUD
Essentially this tool is a hydraulic cylinder or jack which is connected to the end of a bolt by means of a special nut or “puller”. When the cylinder expands under pressure from a pump it raises the puller and stretches the bolt. In order to get access to the nut, the cylinder sits on a “bridge” which supports the weight of the load but allows the operator to reach the nut and turn it down a small “tommy” bar inserted into radial holes either in the nut itself or in a special socket around the nut. Some tensioners have geared mechanisms to adjust the nut, rather than using a bar.
The process involves
1. stretching the stud
2. snugging the nut and
3. releasing the stud
HYDRAULIC TENSIONERS
© HYTORC 2009

25. Initial “pull” load is not the same as “residual” load
Pressure Applied to the Tensioner
Nut Rotated onto the Joint Surface 1 2
Load Path
TENSIONER BOUNCE
Pressure Released from the Tensioner 3
Initial “pull” load is not the same as “residual” load
New Load Path
Hydraulic tensioners do not rely on a blocking point like the torque tools but they create their own set of problems.. No matter how accurately you pull the stud into tension, it is the nut that retains the load, and that nut is tightened by hand. Any slight difference in the angle of turn results in a significant difference between the residual tension in the bolts once they are released.
Also, there is the unavoidable problem of embedment and the change in load path that we call Tensioner Bounce as illustrated above.
HYDRAULIC TENSIONERS
© HYTORC 2009

26. HOW A TENSIONER TRANSFERS LOAD
Here is an animation of how the tensioner transers load from the stud to the bridge and then to the nut.
HYDRAULIC TENSIONERS
© HYTORC 2009

27. Over Tension Needed to Allow for Elastic Recovery
The above graph shows the effect that the length to diameter ratio of the bolt has on the amount of over tension needed to compensate for the relaxation that occurs due to elastic recovery. As can be seen, short thick bolts require a significant percentage of over tensioning to compensate for elastic recovery.
© HYTORC 2009

28. Normally the effective length of the bolt (distance between the midpoints of the nuts) should be at least 8 times its diameter for tensioners to be used L L D
The effect of elastic recovery is greater the thinner the joint (or rather smaller the bolt length to diameter ratio). As indicated in the previous chart the shorter the bolt the higher the percentage of overstretch has to be applied to the bolt to allow for elastic recovery.
If you want a final load of 70% of yield in the bolt you cannot put more than about 25% overstretch in the bolt (allowing for errors) or you run the risk of taking the bolt past yield.
L/D should be at least 8 in most cases for a tensioner to be used. NO D OK
© HYTORC 2009

29. Stud/Thread Protection
Practicalities
For the thread puller on a tensioner to be securely threaded onto the end of the bolt, there needs to be at least a thread protrusion of at least the height of the nut.
Because the end of the threads are exposed when tensioning is employed they are susceptible to damage and corrosion. As a minimum, an anti-seize compound or similar should be used otherwise corrosion can make it extremely difficult for the studs to be removed. Special plastic caps can be obtained that sit over the thread and nut to protect against damage and corrosion.
Because of the protrusion of the thread past the nut, if the nut seizes onto the thread during removal, it is not usually possible to use a standard socket to assist removal.
Stud Protrusion
Stud/Thread Protection
© HYTORC 2009

30. Safety Considerations
Always wear eye protection and gloves.
Always ensure that there is a minimum of 1 D thread protrusion.
Only approach pressurised tensioners when you are certain the pressure is holding
Never exceed the maximum piston stroke of the tensioner.
Never exceed the maximum safe working pressure.
Never attempt to solve leaks when the system is pressurised.
Never attempt to use high pressure equipment when you are in any doubt regarding the correct operation and use. Staff should be trained in the correct use of the equipment and how to check for defects (such as checking hydraulic hoses for cracking and damage).
Always ensure that all personnel in the vicinity are aware that the equipment is under VERY high pressure.
© HYTORC 2009

31. MECHANICAL TENSIONERS
TOOLS THAT TENSION
HYDRAULIC TENSIONERS
MECHANICAL TENSIONERS
The second way to stretch a bolt is with the use of mechanical tensioners.
We will take a look at two:
The LoaDisc and the Clamp.
TENSIONERS
© HYTORC 2009

32. A unique reaction washer
Is:
A unique reaction washer
The Hytorc Load Disc is a unique reaction washer that fits under a regular nut and stops the bolt from turning while the nut draws the stud up with a straight axial pull, tensioning the stud virtually without torsion.
To understand how it works, imagine a stud with two standard nuts jammed together. If we put a wrench on each nut and turn them against one another, as long as we push equally on both wrenches, there will be no torsion imputed to the stud and all the energy will be taken up in locking the two nuts against one another.
Imagine now, that the threads in the bottom nut only extend half way up the nut, and that the threads could somehow break loose and rise as the nuts continue to turn against one another. That is exactly what is happening in the load disc. It acts as a jam nut until fully loaded, then the stud is drawn up and tensioned without any external blocking point, without side loading or torsion in the stud.
It fits under a regular nut and
STOP’S THE BOLT FROM TURNING
© HYTORC 2009

33. COMBINES BENEFITS OF TORQUE AND TENSIONING
Eliminates torsion of torque
Direct axial loading
Provides consistent bearing surface
No external reaction pinch- points
Doesn’t change specifications
Hands-free, even upside down
It combines the benefits of torquing and of tensioning in one tool, without the drawbacks of either one.
© HYTORC 2009

34. (Video of the LoaDisc in action)
© HYTORC 2009

35. A TRUE TENSIONING DEVICE WITHOUT THE DRAWBACKS OF OTHER TENSIONERS
NUT-WITHIN-A-NUT DESIGN
As Near Perfect As The Disc System Is It Still Relies On Turning Against The Threads Of The Existing Stud
This Can Result In Less-than-perfect Friction Conditions And Is Theoretically Subject To Damage
Even these problems are solved with the clamp nut.
A TRUE TENSIONING DEVICE WITHOUT THE DRAWBACKS OF OTHER TENSIONERS
© HYTORC 2009

36. Zero torsion in the stud Direct axial loading with no bending forces
A true tenisioner with the ease of torque
No external reaction or pinch-points
No danger of galling or damage to the stud, ever!
Fast, easy and re-useable
Because the Clamp is a true tensioning device its patented double nut design imputes ZERO TORSION into the stud.
There are no side-loads or bending forces
There are no complex procedures to learn, just put it on and run it down! It is as close to foolproof as any tool ever!
There are no external reaction points and NO PINCH POINTS, because there are no external moving parts.
Because the clamp does not turn on the threads of the stud, there is NO POSSIBLITY OF GALLING THE STUD, EVER!
By the time you get hydraulic tensioners out of the box, with the Clamp, you could be done and on to the next job!
© HYTORC 2009

37. IN ACTION…
(video of the Clamp in action)
© HYTORC 2009

38. Let’s Try A Few Questions
About Bolting Tools
Read the slide)
Please take a few minutes to complete exercise 1 and discuss it.
>
(Quiz #2)
© HYTORC 2009

39. QUIZ
Precision industrial bolting requires high power, accuracy and consistency. Which of these are you likely to achieve with: a pneumatic impact wrench?_______________ a manual torque wrench? _______ ________
2. Which of these manual torque wrenches is “self limiting” and/or notifies the operator that target torque has been reached? _____Clicker ___Deflecting beam ___Electronic
3. T/F An 8:1 multiplier delivers output torque that is 8 times the input torque?
4. The power output of a hydraulic wrench is determined by A. Pump pressure B. Size of the tool piston C. Air pressure D. Both A and B E. Both A and C
5. Which is an advantage of a square drive hydraulic wrench vs. a narrow clearance hydraulic wrench? A. More power for weight B. Fits in tighter places C. Easier to change nut sizes D. Fits on protruding studs
© HYTORC 2009

40. QUIZ (cont.)
6. Which is not generally a concern with hydraulic tensioning? A. Elastic recovery B. Load path change C. Over tensioning D. Coefficient of friction
7. T/F No matter how accurately a hydraulic tensioner pulls the stud, the residual load after the stud is released depends on the adjustment of the nut.
8. Mark “L” for LoaDisc or “C” for Clamp or “B” for both, where each is true: __ Doesn’t turn on stud threads under load __ Less expensive __ Does not require a backup wrench __ Operates hands-free even upside down
© HYTORC 2009

41. C. Easier to change nut sizes by simply changing the impact socket.
Quiz answers:
Power only from an impact. Accuracy and consistency, (but little power) from a manual torque wrench.
D. Both A and B
C. Easier to change nut sizes by simply changing the impact socket.
B and D. Potentially explosive gases or standing water
True. Volume affects how quickly the piston cylinder will fill and empty. Pressure only determines how hard it will push.
© HYTORC 2009