be certain.
m
Series 249G2 Swivels
100-237-294 A
Copyright information © 2011 MTS Systems Corporation. All rights reserved.
Trademark information MTS is a registered trademark of MTS Systems Corporation within the United
States. These trademarks may be protected in other countries.
Molykote is a registered trademark of Dow Chemical Corporation.
Superbolt is a registered trademark of Steinbock Machinery Corporation.
Torquenut is a trademark of Steinbock Machinery Corporation.
Publication information
Manual Part Number Publication Date
September 2011
2
Series 249G2 Swivels
Contents
Technical Support 5
How to Get Technical Support 5
Before You Contact MTS 5
If You Contact MTS by Phone 6
Problem Submittal Form in MTS Manuals 7
Preface 9
Before You Begin 9
Conventions 10
Documentation Conventions 10
Introduction 13
Series 249 Rod Swivel Functional Description 14
Series 249 Rod Swivel Component Identification 15
Series 249 Rod Swivel Specifications 16
Safety Information 17
General Safety Practices 17
Safety Practices Specific to Swivels 18
Installation 21
Mounting a Swivel 21
Mounting for Angularly Applied Loads 22
Maintenance 25
Swivel Bearing Backlash 25
Checking for Swivel Bearing Backlash—Observation Method 26
Checking for Swivel Bearing Backlash—System Response Method 27
Adjusting Backlash 27
Considerations For Superbolt Torquenuts 30
Series 249G2 Swivels
3
4
Series 249G2 Swivels
Technical Support
How to Get Technical Support
How to Get Technical Support
Start with your
manuals
Technical support
methods
MTS web site
www.mts.com
E-mail tech.support@mts.com
Telephone MTS Call Center 800-328-2255
Fax 952-937-4515
The manuals supplied by MTS provide most of the information you need to use
and maintain your equipment. If your equipment includes MTS software, look
for online help and README files that contain additional product inform ation.
If you cannot find answers to your technical questions from these sources, you
can use the internet, e-mail, telephone, or fax to contact MTS for assistance.
MTS provides a full range of support services after your system is installed. If
you have any questions about a system or product, contact MTS in one of the
following ways.
The MTS web site gives you access to our technical support staff by means of a
Technical Support link:
www.mts.com > Contact Us > Service & Technical Support
Weekdays 7:00 A.M. to 5:00 P.M., Central Time
Please include “Technical Support” in the subject line.
Before You Contact MTS
MTS can help you more efficiently if you have the following information
available when you contact us for support.
Know your site
number and system
number
Series 249G2 Swivels Technical Support
The site number contains your company number and identifies your equipment
type (material testing, simulation, and so forth). The number is usually written on
a label on your MTS equipment before the system leaves MTS. If you do not
have or do not know your MTS site number, contact your MTS sales engineer.
Example site number: 571167
When you have more than one MTS system, the system job number identifies
which system you are calling about. You can find your job number in the papers
sent to you when you ordered your system.
Example system number: US1.42460
5
If You Contact MTS by Phone
Know information from
prior technical
If you have contacted MTS about this problem before, we can recall your file.
You will need to tell us the:
assistance
• MTS notification number
• Name of the person who helped you
Identify the problem Describe the problem you are experiencing and know the answers to the
following questions:
• How long and how often has the problem been occurring?
• Can you reproduce the problem?
• Were any hardware or software changes made to the system before the
problem started?
• What are the model numbers of the suspect equipment?
• What model controller are you using (if applicable)?
• What test configuration are you using?
Know relevant
computer information
If you are experiencing a computer problem, have the following information
available:
• Manufacturer’s name and model number
• Operating software type and service patch information
• Amount of system memory
• Amount of free space on the hard drive in which the application resides
• Current status of hard-drive fragmentation
• Connection status to a corporate network
Know relevant
For software application problems, have the following information available:
software information
• The software application’s name, version number, build number, and if
available, software patch number. This information is displayed briefly
when you launch the application, and can typically be found in the “About”
selection in the “Help” menu.
• It is also helpful if the names of other non-MTS applications that are
running on your computer, such as anti-virus software, screen savers,
keyboard enhancers, print spoolers, and so forth are known and available.
If You Contact MTS by Phone
Your call will be registered by a Call Center agent if you are calling within the
United States or Canada. Before connecting you with a technical support
specialist, the agent will ask you for your site number, name, company , company
address, and the phone number where you can normally be reached.
Technical Supp ort
6
Series 249G2 Swivels
Problem Submittal Form in MTS Manuals
If you are calling about an issue that has already been assigned a notification
number, please provide that number. You will be assigned a unique notification
number about any new issue.
Identify system type To assist the Call Center agent with connecting you to the most qualified
technical support specialist available, identify your system as one of the
following types:
• Electromechanical materials test system
• Hydromechanical materials test system
• Vehicle test system
• Vehicle component test system
• Aero test system
Be prepared to
Prepare yourself for troubleshooting while on the phone:
troubleshoot
• Call from a telephone when you are close to the system so that you can try
implementing suggestions made over the phone.
• Have the original operating and application software media available.
• If you are not familiar with all aspects of the equipment operation, have an
experienced user nearby to assist you.
Write down relevant
Prepare yourself in case we need to call you back:
information
• Remember to ask for the notification number.
• Record the name of the person who helped you.
• Write down any specific instructions to be followed, such as data recording
or performance monitoring.
After you call MTS logs and tracks all calls to ensure that you receive assistance and that action
is taken regarding your problem or request. If you have questions about the status
of your problem or have additional information to report, please contact MTS
again and provide your original notification number.
Problem Submittal Form in MTS Manuals
Use the Problem Submittal Form to communicate problems you are experiencing
with your MTS software, hardware, manuals, or service which have not been
resolved to your satisfaction through the technical support process. This form
includes check boxes that allow you to indicate the urgency of your problem and
your expectation of an acceptable response time. We guarantee a timely
response—your feedback is important to us.
The Problem Submittal Form can be accessed:
• In the back of many MTS manuals (postage paid form to be mailed to MTS)
• www.mts.com > Contact Us > Problem Submittal Form (electronic form to
be e-mailed to MTS)
Series 249G2 Swivels Technical Support
7
Problem Submittal Form in MTS Manuals
Technical Supp ort
8
Series 249G2 Swivels
Before You Begin
Preface
Before You Begin
Safety first! Before you use your MTS product or system, read and understand the Safety
manual and any other safety information provided with your system. Improper
installation, operation, or maintenance can result in hazardous conditions that can
cause severe personal injury or death, or damage to your equipment and
specimen. Again, read and understand the safety information provided with your
system before you continue. It is very important that you remain aware of
hazards that apply to your system.
Other MTS manuals In addition to this manual, you may receive additional manuals in paper or
electronic form.
You may also receive an MTS System Documentation CD. It contains an
electronic copy of the manuals that pertain to your test system, such as:
• Hydraulic and mechanical component manuals
• Assembly drawings
• Parts lists
• Operation manual
• Preventive maintenance manual
Controller and application software manuals are typically included on the
software CD distribution disc(s).
Series 249G2 Swivels Preface
9
Conventions
Conventions
Documentation Conventions
The following paragraphs describe some of the conventions that are used in your
MTS manuals.
Hazard conventions Hazard notices may be embedded in this manual. These notices contain safety
information that is specific to the activity to be performed. Hazard notices
immediately precede the step or procedure that may lead to an associated hazard.
Read all hazard notices carefully and follow all directions and recommendations.
Three different levels of hazard notices may appear in your manuals. Following
are examples of all three levels.
Note For general safety information, see the safety information provided with
your system.
Danger notices indicate the presence of a hazard with a high level of risk which,
if ignored, will result in death, severe personal injury, or substantial property
damage.
Warning notices indicate the presence of a hazard with a medium level of risk
which, if ignored, can result in death, severe personal injury, or substantial
property damage.
Caution notices indicate the presence of a hazard with a low level of risk which,
if ignored, could cause moderate or minor personal injury or equipment damage,
or could endanger test integrity.
Notes Notes provide additional information about operating your system or highlight
easily overlooked items. For example:
Note Resources that are put back on the hardware lists show up at the end of
the list.
Special terms The first occurrence of special terms is shown in italics.
Illustrations Illustrations appear in this manual to clarify text. They are examples only and do
Electronic manual
conventions
Preface
10
not necessarily represent your actual system configuration, test application, or
software.
This manual is available as an electronic document in the Portable Document
File (PDF) format. It can be viewed on any computer that has Adobe Acrobat
Reader installed.
Series 249G2 Swivels
Documentation Conventions
Hypertext links The electronic document has many hypertext links displayed in a blue font. All
blue words in the body text, along with all contents entries and index page
numbers, are hypertext links. When you click a hypertext link, the application
jumps to the corresponding topic.
Series 249G2 Swivels Preface
11
Documentation Conventions
12
Preface
Series 249G2 Swivels
Introduction
Contents Series 249 Rod Swivel Functional Description 14
The MTS Series 249 Swivels allow linear actuators to pivot freely at the base and
rod ends.. Two types of swivels are available, base and rod, which allow the use
of swivels at each end of an actuator. Each type of swivel is available in
Adjustable and Non-Adjustable variants. Adjustable swivels have components
that minimize bearing backlash in through zero loading conditions in tensioncompression testing. The following figure shows the four types of swivels.
Series 249 Rod Swivel Component Identification 15
Series 249 Rod Swivel Spec ifications 16
Item Description
1
2
3
4
Series 249G2 Swivels Introduction
Base swivel, non-adjustable
Rod swivel, non-adjustable
Base swivel, adjustable
Rod swivel, adjustable
13
Series 249 Rod Swivel Functional Description
Series 249 Rod Swivel Functional Description
The Series 249 Swivels are used for testing purposes where swivel movement
with minimum backlash is required. They are particularly suited for the demands
of closed-loop servohydraulic testing applications.
The swivels can be mounted to a linear hydraulic actuator, load cell, or
mechanical linkage. A reaction mass, bedplate, or structural component can be
attached to a mounted swivel.
For structural testing applications, a linear actuator equipped with both a swivel
base and swivel rod end provides pivotal freedom at both ends of the actuator (as
shown above).
The swivels are available with force ratings from 25 to 1550 kN (5.5 to 350 kip).
Models are available with or without backlash adju stment in all force ratings.
Depending on the size of the swivel, one of two different types of bolts is used to
clamp the swivel eye.
• 249 Swivels smaller than 500 kN (110 kip) ratings have a single bolt.
• 249 swivels 500 kN (110 kip) and up, which require greater clamping
forces, use a Superbolt Torquenut.
14
Introduction
Series 249G2 Swivels
Series 249 Rod Swivel Component Identification
Series 249 Rod Swivel Component Identification
Series 249 Swivel Components
Callout Component Description
1 Anti-Rotate Tabs
These tabs on the swivel eye restrict the twisting motion of the swivel
assembly.
2 Swivel eye
The base swivel eye can be mounted to the base of the actuator, while
the rod swivel eye is designed for mounting to a load cell or the piston
rod of an actuator. The swivel eye contains the spherical bearing.
3 Swivel jaw
The swivel jaws secure the swivel to the reaction mass. It features two
sides joined by a pin that passes through the spherical bearing.
4 Spherical bearing
The spherical bearing allows the swivel eye to tilt and rotate through a
wide range of motion.
5 Clamping bolt
(adjustable swivels only)
6 Hardened washer
(adjustable swivels only)
7 Adjuster
(adjustable swivels only)
Depending on the size of the swivel, a single bolt or a Superbolt
Torquenut clamps the swivel eye.
A washer under the clamping bolt provides a hardened surface to
tighten against, preventing deformation of the swivel eye.
Available with Series 249 swivels, the adjuster is a threaded sleeve that
screws into and out of the swivel eye to act as a variable shim when
adjusting swivel backlash. Proper adjustment eliminates backlash and
allows the clamping bolt or torque nut to be tightened adequately
without causing excessive friction in the spherical bearing.
Series 249G2 Swivels Introduction
15
Series 249 Rod Swivel Specifications
Series 249 Swivel Components (Continued)
Callout Component Description
8 Spherical washers
(adjustable swivels only)
9Pin
10 (Feature)
11 Sensor cavity
12 Pilot bore
13 (Feature)
14 Accelerometer flat
15 (Feature)
On Series 249 swivels, spherical washers compensate for non-parallel
surfaces within the load path of the swivel eye. Different backlash
adjustment settings may cause the surfaces of the split in the swivel eye
to be non-parallel. The washers ensure this does not compromise
backlash adjustment or damage the clamping bolt.
Secures the spherical bearing to the swivel jaw.
Common eye casting for increased compatibility across product lines.
For force ratings of 160 kN (35 kip) and 340 kN (77 kip) the base end
swivel includes a cavity to contain a Temposonics
® linear-position
sensor. This eliminates the need for a spacer plate, increasing overall
stiffness. The base end also features a cable notch and integrated
Amphenol® connector mounting surface.
Piloting increases alignment accuracy.
Common pin, bearing, retaining ring, and jaw for increased
compatibility across product lines.
The accelerometer flat provides a consistent landing pad for placement
of diagnostic accelerometer for the purpose of measuring force
distortions or backlash when traveling through zero load conditions in
tension–compression loading cycles.
Increased section thickness for strength.
Series 249 Rod Swivel Specifications
Force ratings, weights, dimensions, and operating specifications can be found in
the 249 and 249N Swivel Product Specification on the MTS web site
(www.mts.com
); search keyword “249”.
16
Introduction
Series 249G2 Swivels
Safety Information
This section provides general information about safety issues that pertain to
swivels. Typically, swivels are part of equipment used in MTS structural testing
systems. You are expected to be familiar with safety information th at relates to
the high-pressure and high-performance characteristics of MTS servohydraulic
systems.
General Safety Practices
• Do not use or allow personnel to operate the system who are not
experienced, trained, or educated in the inherent dangers associated with
high-performance servo hydraulics and who are not experienced, trained, or
educated with regard to the intended operation as it applies to this test
system.
• Do not disable safety components or features (including limit detectors,
light curtains, or proximity switches/detectors).
General Safety Practices
• Do not attempt to operate the system without appropriate personal safety
gear (for example, hearing, hand, and eye protection).
• Do not apply charging pressure levels that exceed the maximum pressure
levels of the accumulator.
• Do not modify the system or replace system components using parts that are
not MTS component parts or effect repairs using parts or components that
are not manufactured to MTS specifications.
• Do not use the system in a test area where uncontrolled access to the test
system is allowed when the system is in operation.
• Do not operate the system unless an interlock is installed to monitor supply
pressure into the HSM and initiate a system interlock if a low or no pressure
event occurs.
If you have system related responsibilities (that is, if you are an operator, service
engineer, or maintenance person), you should study safety information carefully
before you attempt to perform any test system procedure.
You should receive training on this system or a similar system to ensure a
thorough knowledge of your equipment and the safety issues that are associated
with its use. In addition, you should gain an understanding of system functions
by studying the other manuals supplied with your test system. Contact MTS for
information about the content and dates of training classes that are offered.
It is very important that you study the following safety information to ensure that
your facility procedures and the system’s operating environment do not
contribute to or result in a hazardous situation. Remember, you cannot eliminate
all the hazards associated with this system, so you must learn and remain aware
of the hazards that apply to your system at all times. Use these safety guidelines
to help learn and identify hazards so that you can establish appropriate training
and operating procedures and acquire appropriate safety equipment (such as
gloves, goggles, and hearing protection).
Series 249G2 Swivels Safety Information
17
Safety Practices Specific to Swivels
Each test system operates within a unique environment which includes the
following known variables:
• Facility variables (facility variables include the structure, atmosphere, and
utilities)
• Unauthorized customer modifications to the equipment
• Operator experience and specialization
• Test specimens
Because of these variables (and the possibility of others), your system can
operate under unforeseen circumstances that can result in an operating
environment with unknown hazards.
Improper installation, operation, or maintenance of your system can result in
hazardous conditions that can cause death, personal injury, or damage to the
equipment or to the specimen. Common sense and a thorough knowledge of the
system’s operating capabilities can help to determine an appropriate and safe
approach to its operation.
Safety Practices Specific to Swivels
Read all manuals Study the contents of this manual and the other manuals provided with your
system before attempting to perform any system function for the first time.
Procedures that seem relatively simple or intuitively obvious may require a
complete understanding of system operation to avoid unsafe or dangerous
situations.
Check for swivel
bearing backlash
During system operation, you should examine the swivel assembly to determine
if there are any visible signs of backlash. If possible, this examination should be
performed immediately after system installation, so that you can better recognize
the “normal” appearance, sound, and feel of a properly adjusted swivel in case an
adjustment becomes necessary in the future.
When a swivel bearing is too loose, the amount of force measured as the actuator
moves from compression to tension can exhibit a small signal discontinuity
during the load reversal. Swivel bearing backlash can also produce an audible
clicking noise from the spherical bearing. This sound might be difficult or
impossible to hear above the noise of the other components in the testing system.
Using a stethoscope can enable you to hear the noise and determine if backlash is
present.
Proper adjustment of the backlash enables the swivel to tilt and rotate without
damaging the bearing or distorting test results. If backlash appears to be the cause
of unacceptable test results, a small adjustment can be made to the swivel. If the
adjustment does not improve the test results, other possible sources of distortion
should be checked.
Locate and read
hazard placards/labels
Safety Information
18
Find, read, and follow the hazard placard instructions located on the equipment.
These placards are placed strategically on the equipment to call attention to areas
such as known crush points, electrical voltage, and high pressure hazards.
Series 249G2 Swivels
Safety Practices Specific to Swivels
Know facility safe
procedures
Most facilities have internal procedures and rules regarding safe practices within
the facility. Be aware of these safe practices and incorporate them into your daily
operation of the system.
Have first aid available Accidents can happen even when you are careful. Arrange your operator
schedules so that a properly trained person is always close by to render first aid.
In addition, ensure that local emergency contact information is posted clearly and
in sight of the system operator.
Be aware of
component movement
with hydraulics off
Keep bystanders
safely away
The actuator rod can also drift down when hydraulics are turned off hitting
anything in its path. This uncommanded movement is because of oil movement
between the pressure/return ports and oil blow by across the piston hub. Be aware
that this can happen and clear the area around the actuator rod when hydraulics
are turned off.
Keep bystanders at a safe distance from all equipment. Never allow bystanders to
touch specimens or equipment while the test is running.
Wear proper clothing Do not wear neckties, shop aprons, loose clothing or jewelry, or long hair that
could get caught in equipment and result in an injury. Remove loose clothing or
jewelry and restrain long hair.
Check bolt ratings and
torques
To ensure a reliable product, fasteners (such as bolts and tie rods) used in MTSmanufactured systems are torqued to specific requirements. If a fastener is
loosened or the configuration of a component within the system is modified, refer
to information in this product manual to determine the correct fastener, fastener
rating, and torque. Overtorquing or undertorquing a fastener can create a
hazardous situation due to the high forces and pressures present in MTS test
systems.
Practice good
housekeeping
Do not disable safety
devices
Provide adequate
lighting
Provide means to
access out-of-reach
components
On rare occasions, a fastener can fail even when it is correctly installed. Failure
usually occurs during torquing, but it can occur several days later. Failure of a
fastener can result in a high velocity projectile. Therefore, it is a good practice to
avoid stationing personnel in line with or below assemblies that contain large or
long fasteners.
Keep the floors in the work area clean. Hydraulic fluid that is spilled on any type
of floor can result in a dangerous, slippery surface. Do not leave tools, fixtures,
or other items not specific to the test, lying about on the floor, system, or decking.
Your system may have active or passive safety devices installed to prevent
system operation if the device indicates an unsafe condition. Do not disable such
devices as it may result in unexpected system motion.
Ensure adequate lighting to minimize the chance of operation errors, equipment
damage, and personal injury. You need to see what you are doing.
Make sure you can access system components that might be out of reach while
standing on the floor. For example, ladders or scaffolding might be required to
reach load cell connectors on tall load units.
Series 249G2 Swivels Safety Information
19
Safety Practices Specific to Swivels
Wear appropriate
personal protection
Know servohydraulic
system interlocks
Wear eye protection when you work with high-pressure hydraulic fluid,
breakable specimens, or when anything characteristic to the specimen could
break apart.
W ear ear protection when you work near electric motors, pumps, or other devices
that generate high noise levels. Some systems can create sound pressure levels
that exceed 70 dbA during operation.
W ear appropriate personal protection equipment (gloves, boots, suits, respirators)
whenever you work with fluids, chemicals, or powders that can irritate or harm
the skin, respiratory system, or eyes.
Interlock devices should always be used and properly adjusted. Interlock devices
are designed to minimize the chance of accidental damage to the test specimen or
the equipment. Test all interlock devices for proper operation immediately before
a test. Do not disable or bypass any interlock devices as doing so could allow
hydraulic pressure to be applied regardless of the true interlock condition. The
Reset/Override button is a software function that can be used to temporarily
override an interlock while attempting to start the hydraulic power unit and gain
control of the system.
Know system limits Never rely on system limits such as mechanical limits or software limits to
protect you or any personnel. System limits are designed to minimize the chance
of accidental damage to test specimens or to equipment. T est all limits for proper
operation immediately before a test. Always use these limits and adjust them
properly.
Do not disturb sensors Do not bump, wiggle, adjust, disconnect, or otherwise disturb a sensor (such as
an accelerometer or extensometer) or its connecting cable when hydraulic
pressure is applied.
Stay alert A void long periods of work without adequate rest. In addition, avoid long periods
of repetitious, unvarying, or monotonous work because these conditions can
contribute to accidents and hazardous situations. If you are too familiar with the
work environment, it is easy to overlook potential hazards that exist in that
environment.
Stay clear of moving
equipment/avoid crush
points
Know the causes of
unexpected actuator
motions
Stay clear of mechanical linkages, connecting cables, and hoses that move
because you can get pinched, crushed, tangled, or dragged along with the
equipment. High forces generated by the system can pinch, cut, or crush anything
in the path of the equipment and cause serious injury. Stay clear of any potential
crush points. Most test systems can produce sudden, high-force motion. Never
assume that your reactions are fast enough to allow you to escape injury when a
system fails.
The high force and velocity capabilities of MTS actuators can be destructive and
dangerous (especially if actuator motion is unexpected). The most likely causes
of unexpected actuator response are operator error and equipment failure due to
damage or abuse (such as broken, cut, or crushed cables and hoses; shorted wires;
overstressed feedback devices; and damaged components within the servocontrol
loop). Eliminate any condition that could cause unexpected actuator motion.
Safety Information
20
Series 249G2 Swivels
Installation
Mounting
Bore
Thickness
Contents Mounting a Swivel 21
Mounting a Swivel
This section describes how to install the Series 249 Swivels to the foundation.
For information is attaching the swivels to actuator rods, refer to the appropriate
actuator product manual.
Mounting for Angularly Applied Loads 22
Rigid support for
swivel mounts
The swivel base assembly is not designed to rigidly support an actuator for
vertical operation. In general, actuators that require rigid support are equipped
with a pedestal base accessory. Should it become necessary to rigidly support an
actuator with a swivel base assembly , contact MTS Systems Corporation for rigid
support recommendations.
Mounting a Swivel
All models of the Series 249 Swivels can be mounted with four socket head bolts.
The mounting bolt size is determined by the model number. See the following
table for the recommended mounting bolt size, torque, grade, and mounting bore
thickness.
Mounting Bolt Size, Torque & Grade Requirements
Model Recommended Mounting
Bolt Size
SI Metric U.S.
Customary
249xx.M25 M10 x 1.50 3/8 in-16 53 34 12.9 8 24.6 0.97
249xx.M70 M16 x 2.00 5/8 in-11 230 160 12.9 8 38.1 1.50
249xx.M160 M16 x 2.00 5/8 in-11 230 160 12.9 8 57.2 2.25
Mounting Bolt
Tor que
N•m lbf-ft IS SAE mm in
Recommended
Bolt Grade
Mounting Bore
Thickness
249xx.M340 M24 x 3.00 1 in-8 780 680 12.9 8 127 5.00
249xx.M500 M30 x 3.50 1-1/4 in-7 1600 1360 12.9 8 110 4.31
249xx.M730 M30 x 3.50 1-1/4 in-7 1600 1360 12.9 8 230 9.06
249xx.M1000 M42 x 4.50 1-1/2 in-6 3200 2400 12.9 8 312 12.30
249xx.M1550 M48 x 5.00 1-3/4 in-5 5000 3700 12.9 8 445 17.50
Series 249G2 Swivels Installation
21
Mounting for Angularly Applied Loads
Retaining
Stops
Retaining
Stops
Before mounting the swivel, apply Molykote® G grease, or equivalent, to the
threads and under the head of each mounting bolt. Tighten each bolt until it is
firmly seated against the swivel. Then, using the pattern shown in the following
figure, tighten the bolts to one-half of the recom m e nded torque value. Continue
using this pattern to tighten the bolts to their final torque value.
Mounting for Angularly Applied Loads
Mounting Bolt Tightening Sequence
If the swivel mounting surface is not perpendicular to the direction of applied
force, it might be necessary to install retaining stops to prevent the swivel from
slipping. Slippage can be expected if the operating forces for the angle of load
application are exceeded.
The following figure shows the position of the retaining stops and the angle of
load application.
22
Installation
Series 249G2 Swivels
Mounting for Angularly Applied Loads
F (force to produce slippage)
90
80
70
60
50
40
30
20
10
0
3000
13.344
5000
22.241
7000
31.137
10,000
44.482
20,000
88.964
40,000
177.928
60,000
266.892
100,000
444.820
200,000
889.640
β (degrees of rotation from the vertical )
lbf
kN
400,000
1,779.28
2000
8.896
249.xx.M25
249.xx.M70
249.xx.M160
249.xx.M340
249.xx.M500
249.xx.M1000
Different system configurations require the use of different types of retaining
stops. In all cases, the retaining stops must withstand a shear force equal to or
greater than the forces specified in the following illustrations.
249.xx.M70
20,000
88.964
249.xx.M160
40,000
177.928
249.xx.M340
60,000
266.892
80,000
355.851
100,000
444.820
249.xx.M500
120,000
533.777
140,000
622.740
160,000
711.702
249.xx.M1000
180,000
800.665
249.xx.M25
90
80
70
60
50
40
30
(degrees of rotation from the vertical)
20
β
10
0
lbf
0
kN
Shear strength of retaining stops
Systems that require the swivels to react angularly to applied tensile and
compressive loads should also take into account the possibility of backlash
between the retaining stops and the swivel jaw. The retaining stops should be
mounted in a manner that will eliminate or minimize this backlash.
Series 249G2 Swivels Installation
23
Mounting for Angularly Applied Loads
24
Installation
Series 249G2 Swivels
Maintenance
Contents Swivel Bearing Backlash 25
Overview Maintenance for the Series 249 Swivels consist of periodic checks and, if
Swivel Bearing Backlash
Checking for Swivel Bearing Backlash—Observation Method 26
Checking for Swivel Bearing Backlash—System Response Method 27
Adjusting Backlash 27
Considerations For Superbolt Torquenuts 30
necessary, adjusting the backlash. Series 249N are not backlash adjustable, and
therefore do not require maintenance of the clamping bolt system. They still,
however, should be periodically checked for excessive bearing movement and
noise. The spherical bearing used in the swivels should not be lubricated.
Series 249 Swivels are usually shipped from MTS with the backlash adjusted and
are ready for immediate use. However, the backlash should be checked and, if
necessary, adjusted prior to use in the field. Backlash should be checked again
after four to five hours of initial use and as often as necessary thereafter.
Operating a swivel with excessive backlash can result in system instability, poor
control of load when passing through zero, and rapid bearing wear due to shock
loading effects. Proper backlash adjustment will prolong the life of the swivel
and enhance the system’s performance and fidelity.
Swivel Bearing Backlash
The acceptable amount of backlash in a given test system depends on the forces
the swivel must react to and the sensitivity of the test. If a smooth transition
between tension and compression loads is not required, a small amount of
backlash might not affect test results. Determining whether or not the swivel
bearing backlash adjustment is compatible with the sensitivity requirements of
the test requires you to carefully consider the function of the swivel within the
test setup.
T esting systems that use the swivel primarily as a tool to align the components of
the force train during application of tensile or compressive forces, but not both,
will probably not be affected by a certain amount of swivel bearing backlash.
Testing systems that use the swivel during dynamic tensile and compressive
loading of a specimen/structure can be adversely affected by a swivel bearing
adjustment that is too loose or too tight.
The following describe the methods which can be used to determine if it is
necessary to adjust the swivel bearing backlash.
Series 249G2 Swivels Maintenance
25
Checking for Swivel Bearing Backlash—Observation
Checking for Swivel Bearing Backlash—Observation Method
During system operation, you should examine the swivel assembly to determine
if there are any visible signs of backlash. If possible, this examination should be
performed immediately after system installation, so that you can better recognize
the “normal” appearance, sound, and feel of a properly adjusted swivel in case an
adjustment becomes necessary in the future.
Never allow any part of your body to get in the path of motion of any
hydraulic component or its associated fixturing. Never rely on your reflexes
to protect you from unexpected actuator movement.
Actuator and associated fixturing movement can injure personnel or
damage equipment it comes in contact with. Unexpected actuator
movement can happen much too quickly for you to get out of the way.
Touch or stand near hydraulic equipment only if you are not in the path of motion
of any actuator or its associated fixturing. If it is not possible to access the
equipment without crossing the path of motion, do not attempt to access the
equipment.
Swivel bearing backlash can produce an audible clicking noise from the spherical
bearing. This sound might be difficult or impossible to hear above the noise of
the other components in the testing system. Using a stethoscope can enable you
to hear the noise and determine if backlash is present.
When there is an excessive amount of backlash, there can be a visible separation
between the ball and race of the spherical bearing. This separation will be quite
small, and the position of the swivel can make it impossible to observe. Care
should be taken to differentiate between deflection and backlash. Deflection
appears as relative motion between the swivel eye and jaw. Some amount of
swivel deflection is normal. Backlash is distinguished from deflection by relative
motion between the ball and race of the spherical bearing.
Extreme care should be take before attempting to feel backlash.
An unexpected actuator motion could cause grave injuries to the person
checking the swivel.
Unless the swivel assembly can be accessed from a position that provides
adequate protection from unexpected actuator movement, you should not attempt
to “feel” the backlash in the system.
26
Maintenance
The presence of swivel bearing backlash can often be detected by the “feel” of
the swivel. If backlash is present, a mild thumping sensation can be felt when a
hand is placed on the surface of the swivel.
Series 249G2 Swivels
Checking for Swivel Bearing Backlash—System
These methods will only detect large amounts of swivel bearing backlash. If the
backlash can be seen, heard, or felt, the swivels require adjustment.
Checking for Swivel Bearing Backlash—System Response Method
When a swivel bearing is too loose, the amount of force measured as the actuator
moves from compression to tension can exhibit a small signal discontinuity
during the load reversal. The following figure shows this relationship for a
system designed to measure small changes in load.
Adjusting Backlash
Presence of Backlash During Load Reversals
Note The signal discontinuity from backlash might only be one component of
the load signal distortion. Be aware of other possible load signal
distortion sources in the force train, such as a loose mounting bolt.
If the test results appear to be adversely affected by the presence of swivel
bearing backlash, a small adjustment can be made to the swivel to determine
whether or not it is the cause of the problem.
Proper adjustment of the backlash enables the swivel to tilt and rotate without
damaging the bearing or distorting test results. If backlash appears to be the cause
of unacceptable test results, a small adjustment can be made to the swivel. If the
adjustment does not improve the test results, other possible sources of distortion
should be checked.
There is a direct relationship between the amount of clamping force required to
remove backlash and the frictional torque necessary to rotate the swivel. If the
backlash adjustment is too tight, high frictional torque will cause the spherical
bearing to overheat and eventually fail. To avoid this condition, the backlash
adjustment must be made in small steps, checked, and then if necessary
readjusted.
The following contains the procedures required to complete the adjustment
process. The following table shows the type of clamping bolt and clamping
torque required by each swivel. The torque values identified in this table are used
in the following procedures. These procedures require the use of a spanner and a
torque wrench fitted with the appropriate size socket or hex key.
Series 249G2 Swivels Maintenance
27
Adjusting Backlash
Tightening the swivel bearing backlash adjustment beyond recommended
levels can significantly increase the heat and friction produced by the
swivel during operation.
Increased heat and friction on the swivel assembly can cause the bearing to
fail and result in damage or injury to equipment and personnel.
Carefully follow the backlash adjustment procedure, and do not exceed the
specified backlash adjuster clamping torque.
If backlash is observed using one of the methods discussed in the previous
section, complete the following procedure to remove the backlash.
1. Position the swivel in a secure, convenient, static position that allows access
to the swivel adjuster and clamping bolt. Ensure that hydraulic hoses and
servovalve cables are properly connected.
2. Remove hydraulic pressure from the system.
3. Turn the adjuster out until contact is just made with the spherical washer.
4. Torque the clamping screw to its full value as shown in the following table.
When properly set with zero backlash, the torque to swivel the eye should
be within the range shown in the following table. If it is not, the clamping
screw should be untorqued and the adjuster repositioned. If the torque to
swivel the eye was too high, turn the adjuster counterclockwise decreasing
the gap between it and the spherical washers. If it was too low, turn the
adjuster clockwise increasing the gap. Never set a swivel with the adjuster
extended to force the eye open.
If the swivel used the Superbolt Torquenut, refer to “Considerations For
Superbolt Torquenuts” on page 30 for additional information.
28
Maintenance
Series 249G2 Swivels
Adjusting Backlash
Note In the following table, the torque to swivel eye when properly adjusted
specification is F = L x H.
L
F
Swivel Rotation
Force Rating Tilt Angle Swivel Angle Adjuster Bolt
Clamping Torque
25kN (5.5kip)
70 kN (15 kip)
160 kN (35 kip)
340 kN (77 kip)
500 kN (110 kip)
730 kN (165 kip)
1000 kN (220 kip)
1550 kN (350 kip)
*. Superbolt Torquenut. Torque in 34 N·m (25 ft-lbf) increments until all screws reach 61 N·m
(45 ft-lbf). See “Considerations For Superbolt Torquenuts” on page 30 for additional information.
†. Contact MTS Systems for information on this swivel.
†
7
° +90°, -90°
17
° +90°, -75°
17
° +90°, -80°
14
° +90°, -75°
6
° +90°, -30°
17
° +90°, -80°
14
° +90°, -75°
-- --
33.8 N·m (25 ft-lbf) 31.2 to 36.6 N·m
108.4 N·m (80 ft-lbf) 67.8 to 81.3 N·m
379.6 N·m (280 ft-lbf) 108.5 to 135.6 N·m
921.9 N·m (680 ft-lbf) 433.8 to 501.6 N·m
61 N·m (45 ft-lbf)
61 N·m (45 ft-lbf)* 949 to 1152 N·m
61·m (45 ft-lbf)* 1898 to 3204 N·m
-- --
Torque to Swivel Eye
when Properly Adjusted
(23 to 27 ft-lbf)
(50 to 60 ft-lbf)
(80 to 100 ft-lbf)
(320 to 370 ft-lbf)
*
745 to 881 N
(550 to 650 ft-lbf)
(700 to 850 ft-lbf)
(1400 to 1700 ft-lbf)
·m
Series 249G2 Swivels Maintenance
29
Considerations For Superbolt Torquenuts
Jackbolts
Main thread
Top View
Side View
Jackbolt
Torquenut
Hardened washer
Spherical washers
Swivel
5. Apply hydraulic pressure and check for backlash using the methods
described previously.
Note The increased amount of force that will be required to rotate and tilt the
swivel when it is set to an extremely tight backlash adjustment can
introduce unwanted forces into the testing system. Therefore, setting the
adjuster so that it just barely contacts the spherical washer when fully
torqued should not be considered th e optimum backlash adjustment
setting. The optimum setting is determined by the performance
requirements of the testing system.
6. If unacceptable backlash is still observed, repeat Steps 1 through 5 until it is
eliminated.
Considerations For Superbolt Torquenuts
The Model 249xx.M500 through 249xx.M1550 Swivel assemblies use a
Superbolt Torquenut as the clamping bolt, instead of the standard bolt used in the
smaller swivel assemblies. The method used to tighten and loosen the Torquenuts
is included in the following procedure.
An ordinary torque wrench and an appropriate size hex key socket are the only
tools required to loosen or tighten the jackbolts on a Torquenut.
30
Maintenance
Do not loosen the jackbolts on the Torquenut without following the
instructions in this procedure.
Damage to the hardened washer can occur if the jackbolts are not loosened
evenly and in the proper sequence.
Ensure that the jackbolts are not loosened more than one-eighth turn at a time,
and that the proper loosening sequence is followed.
Series 249G2 Swivels
Considerations For Superbolt T o rquenut s
1. Following the sequence shown below, loosen every third jackbolt oneeighth turn at a time. Repeat this process until all of the jackbolts can be
turned by hand. This will prevent a single jackbolt from bearing the entire
load of the Torquenut
.
2. After all the jackbolts have been loosened, loosen the Torquenut on the main
thread by turning the nut by hand or with a bar inserted between the
jackbolts (do not damage the threads of the jackbolts).
3. Ensure that none of the jackbolts protrude through the base of the
Torquenut, and that the surface of the Torquenut rests smoothly on the
hardened washer. Tighten the To rquenut on the main thread by turning the
nut by hand or with a bar inserted between the jackbolts (do not damage the
threads of the jackbolts).
4. After the backlash adjustment has been made, hand-tighten each jackbolt to
ensure even seating of the main thread.
5. Using the torque wrench, tighten the jackbolts in the same sequence they
were loosened. Torque in 34 N·m (25 ft-lbf) increments until all screws
reach 61 N·m (45 ft-lbf).
It will be necessary to torque each jackbolt several times, because the
preceding jackbolts will loosen as the subsequent jackbolts are torqued.
Using the same method, torque each jackbolt to a final clamping torque of
61 N·m (45 lbf·ft).
Series 249G2 Swivels Maintenance
31
Considerations For Superbolt Torquenuts
32
Maintenance
Series 249G2 Swivels
m
MTS Systems Corporation
14000 Technology Drive
Eden Prairie, Minnesota 55344-2290 USA
Toll Free Phone: 800-328-2255
(within the U.S. or Canada)
Phone: 952-937-4000
(outside the U.S. or Canada)
Fax: 952-937-4515
E-mail: info@mts.com
Internet: www.mts.com
ISO 9001 Certified QMS
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