MTS 249 User Manual

Series 249 Swivels
Product Information

l

011-775-600 E

Copyright information © 1985, 1986, 1994, 1999, 2008 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.

Contact information MTS Systems Corporation

14000 Technology Drive
Eden Prairie, Minnesota 55344-2290 USA
Toll Free Phone: [phone] (within the U.S. or Canada)
Phone:[phone] (outside the U.S. or Canada)
Fax: [phone]
E-mail: [e-mail]
http://www.mts.com

Publication information

Manual Part Number Publication Date

117756-00A October 1985

117756-00B April 1986

117756-00C May 1994

011-775-600 D December 1999

011-775-600 E March 2008

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 Component Identification 14

Series 249 Rod Swivel Functional Description 15

Series 249 Rod Swivel Specifications 16

Model 249.12 Dimensions 18

Model 249.20 Dimensions 19

Model 249.23 Dimensions 20

Model 249.32 Dimensions 21

Model 249.41 Dimensions 22

Model 249.42 Dimensions 23

Model 249.51 Dimensions 24

Installation 25

Mounting a Swivel 25

Mounting for Angularly Applied Loads 26

Series 249 Rod Swivel Product Manual

3

Maintenance 29

Swivel Bearing Backlash 29

Checking for Swivel Bearing Backlash—Observation Method 29

Checking for Swivel Bearing Backlash—System Response Method 31

Adjusting Backlash 31

Adjusting Models 249.12/.20/.23/.32 32

Adjusting Models 249.41/.42/.51 33

4

Series 249 Rod Swivel Product Manual

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 [e-mail]

Telephone MTS Call Center 800-328-2255

Fax [phone]

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 information.

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 249 Rod Swivel Product Manual 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 Support

6

Series 249 Rod Swivel Product Manual

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 249 Rod Swivel Product Manual Technical Support

7

Problem Submittal Form in MTS Manuals

Technical Support

8

Series 249 Rod Swivel Product Manual

Before You Begin

Preface

Before You Begin

Safety first! Before you attempt to 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 of MTS equipment in your test
facility can result in hazardous conditions that can cause severe personal injury or
death and 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 MTS manuals in paper or

electronic form.

If you have purchased a test system, it may include an MTS System
Documentation CD. This CD contains an electronic copy of the MTS manuals
that pertain to your test system, including hydraulic and mechanical component
manuals, assembly drawings and parts lists, and operation and preventive
maintenance manuals. Controller and application software manuals are typically
included on the software CD distribution disc(s).

Series 249 Rod Swivel Product Manual Preface

9

Conventions

DANGER

WARNING

CAUTION

Conventions

Documentation Conventions

The following paragraphs describe some of the conventions that are used in your
MTS manuals.

Hazard conventions As necessary, hazard notices may be embedded in this manual. These notices

contain safety information that is specific to the task 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 the directions that are given.
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, equipment damage, or
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. It is important for you to be

Electronic manual

conventions

Preface

10

aware that these illustrations are examples only and do 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 249 Rod Swivel Product Manual

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 249 Rod Swivel Product Manual Preface

11

Documentation Conventions

12

Preface

Series 249 Rod Swivel Product Manual

Introduction

Base Swivel

Rod End Swivel

Contents Series 249 Rod Swivel Component Identification 14

The MTS Series 249 Swivels allow hydraulic actuators to operate with a degree
of movement. Two types of swivels are available, which allow the use of swivels
at each end of an actuator. The following figure shows both types of swivels.

Series 249 Rod Swivel Functional Description 15

Series 249 Rod Swivel Specifications 16

Model 249.12 Dimensions 18

Model 249.20 Dimensions 19

Model 249.23 Dimensions 20

Model 249.32 Dimensions 21

Model 249.41 Dimensions 22

Model 249.42 Dimensions 23

Model 249.51 Dimensions 24

Series 249 Swivels

Series 249 Rod Swivel Product Manual Introduction

13

Series 249 Rod Swivel Component Identification

Clamping
Bolt

Eye
Insert

Spherical
Washers

Spherical
Bearing

Backlash
Adjuster

Swivel Eye

Retaining Ring

Pin

Swivel Jaw

Series 249 Rod Swivel Component Identification

Series 249 Swivel Components

OMPONENT DESCRIPTION

C

Swivel eye

Pin

Swivel jaw

Spherical bearing

Clamping bolt

Eye insert

Backlash adjuster

Spherical washers

Introduction

14

Contains the spherical bearings. There are two mounting styles:

• The base type has a bolt pattern on the top that is suitable for mounting the

base of an actuator to it.

• The rod end type is designed for mounting to a load cell or the piston rod

of an actuator. The Models 249.12/.20/.23, and .32 rod end types are
internally tapped to accept a threaded stud. The larger Model 249.41,

249.42, and .51 rod end types are mounted with an adapter plate.

Secures the spherical bearing to the swivel jaw.

Secures the swivel to the reaction mass. It is comprised of two sides joined by a
pin passing through the spherical bearing.

Allows the swivel eye to tilt and rotate through a wide range of motion.

Depending on the size of the swivel, a single bolt or a Superbolt Torquenut
clamps the swivel eye.

Provides a hardened surface to tighten against, and prevents deformation of the
swivel eye.

A threaded sleeve that screws into and out of the swivel eye to act as a variable
shim when adjusting the swivel backlash.

Compensate for non-parallel surfaces within the load path of the swivel eye.
Different backlash adjustment settings can cause the surfaces of the split in the
swivel eye to no longer be parallel. The spherical washers ensure that this does
not adversely effect the backlash adjustment or damage the clamping bolt.

Series 249 Rod Swivel Product Manual

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.

Series 249 Rod Swivel Functional Description

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 to the right).

The swivels are available in six different models with force ratings from 25 to
1000 kN (5.5 to 220 kip).

Depending on the size of the swivel, one of two different types of bolts is used to
clamp the swivel eye.

• Models 249.12/.20/.23, and .32 use a single bolt.

• The larger Models 249.41/.42, and .51, which require greater clamping

forces, use a Superbolt Torquenut.

Series 249 Rod Swivel Product Manual Introduction

15

Series 249 Rod Swivel Specifications

Series 249 Rod Swivel Specifications

The following tables list the swivel base and swivel rod end force rating, the
weight specifications, and the swivel base and swivel rod end operational
specifications.

Force Rating and Weight Specifications

ODEL FORCE RATING BASE WEIGHT ROD END WEIGHT

M

249.12 25 kN (5.5 kip) 2.9 kg (6.5 lb) 2.1 kg (4.6 lb)

249.20 70 kN (15 kip) 13 kg (28 lb) 11 kg (24 lb)

249.23 160 kN (35 kip) 30 kg (66 lb) 27 kg (60 lb)

249.32 340 kN (77 kip) 75 kg (166 lb) 66 kg (146 lb)

249.41 500 kN (110 kip) 157 kg (346 lb) 178 kg (393 lb)*

249.42 730 kN (165 kip) 268 kg (590 lb) 213 kg (690 lb)*

249.51 1000 kN (220 kip) 454 kg (1000 lb) 510 kg (1125 lb)*

*Swivel rod end weight includes the adapter.

Operational Specifications

ODEL TILT ANGLE (α)* SWIVEL ANGLE (ß)

M

249.12

249.20 ±17° -75°, +90°

249.23 ±17° -80°, +90°

249.32 ±14° -75°, +90°

249.41 ±6° -30°, +90° – 62 N·m (45 lb·ft)

249.42

249.51 ±8° -30°, +90°

±7°

±7°

§

§

±90° – 34 N·m (25 lb·ft)

-30°, +90°

WIVEL BASE SPRING RATE

S

7.0 x106 N/cm (3.9 x106 lb/in)

12.4 x106 N/cm (7.0 x106 lb/in)

18.9 x106 N/cm (10.7 x106 lb/in)

6

56.5 x10

44.1 x106 N/cm (25 x106 lb/in)

N/cm (32 x106 lb/in)

†

CLAMPING BOLT TORQUE

110 N·m (81 lb·ft)

380 N·m (280 lb·ft)

920 N·m (678 lb·ft)

62 N·m (45 lb·ft)

62 N·m (45 lb·ft)

* Tilt angle capability is reduced when swivel angle exceeds ±30°.

† Contact MTS for spring rates not given in this table.
‡ Models 249.41, 249.42, and 249.51 use a Superbolt Torquenut. Each jackbolt in the torquenut is

torqued to 62 N·m (45 lbf-ft).

§ Optional ±15° tilt angle is available.

‡

16

Introduction

Series 249 Rod Swivel Product Manual

Series 249 Rod Swivel Specifications

Swivel Angle

Tilt Angle

Series 249 Rod Swivel Product Manual Introduction

17

Model 249.12 Dimensions

62.9 mm
(2.475 in.)

10.3 mm
(0.406 in.)
diameter

88.9 mm (3.50 in.)

88.9 mm
(3.50 in.)

62.9 mm
(2.475 in.)

Thread M12 x 125
mm (1/2-20 UNS-2B)

73.0 mm
(2.875 in.)

73.0 mm
(1.875 in.)

10.4 mm
(0.41 in.)

24.6 mm
(0.97 in.)

47.6 mm (1.875 in.)

79.4 mm (3.125 in.)

Bolt Pattern

For Actuator Base

For Actuator Rod

Footprint

10.7 mm
(0.422 in.)
diameter

63.6 mm
(2.50 in.)

63.6 mm (2.50 in.)

85.8 mm (3.38 in)

83.6 mm
(3.29 in)

Depth 19.0 mm
(0.75 in.)

Model 249.12 Dimensions

Introduction

18

Series 249 Rod Swivel Product Manual

Model 249.20 Dimensions

89.9 mm
(3.54 in.)

17.3 mm
(0.68 in.)
diameter

133.4 mm
(5.25 in.)

133.4 mm
(5.25 in.)

89.9 mm (3.54 in.)

Bolt Pattern

If present—used to align the
LVDT base. Refer to Actuator
Product Manual

15.7 mm
(0.62 in.)

104.7 mm (4.12 in.)

76.2 mm (3.00 in.)

For Actuator Base

38.1 mm
(1.50 in.)

17.5 mm
(0.69 in.)
diameter

Footprint

114.3 mm
(4.50 in.)

Thread M27 x 2 mm

(1-14 UNS-2B)
Depth 35.0 mm
(1.38 in.)

121.9 mm (4.80 in.)

76.2 mm (3.00 in.)

For Actuator Rod

114.3 mm (4.50 in.)

142.7 mm
(5.62 in.)

142.7 mm (5.62 in.)

Model 249.20 Dimensions

Series 249 Rod Swivel Product Manual Introduction

19

Model 249.23 Dimensions

16.8 mm
(0.66 in.)
diameter

89.9 mm (3.54 in.)

89.9 mm
(3.54 in.)

139.7 mm (5.50 in.)

139.7 mm
(5.50 in.)

Bolt Pattern

If present–used to align
the LVDT base. Refer to
Actuator Product Manual

12.7 mm
(0.50 in.)

136.7 mm (5.38 in.)

101.6 mm (4.00 in.)

57.2 mm (2.25 in.)

For Actuator Base

Thread M27 x 2mm
(1-14 UNS-2B)

Depth 50.8 mm

(2.00 in.)

162.0 mm (6.38 in.)

101.6 mm (4.00 in.)

For Actuator Rod

17.5 mm
(0.69 in.)
diameter

Footprint

187.5 mm (7.50 in.)

146.1 mm (5.75 in.)

146.1 mm
(5.75 in.)

196.9 mm
(7.87 in.)

Model 249.23 Dimensions

20

Introduction

Series 249 Rod Swivel Product Manual

Model 249.32 Dimensions

238.0 mm
(9.37 in.)

231.6 mm
(9.12 in.)

184.1 mm
(7.25 in.)

184.1 mm
(7.25 in.)

Footprint

26.9 mm
(1.06 in.)
diameter

For Actuator Rod

127.0 mm
(5.00 in.)

Thread
M36 x 2 mm
( 1.5-12 UN-2B)

Depth

76.2 mm
(3.00 in.)

215.9 mm
(8.50 in.)

139.7 mm
(5.50 in.)

For Actuator Base

127.0 mm
(5.00 in.)

25.4 mm
(1.00 in.)

If present–used to align the
LVDT base. Refer to
Actuator Product Manual.

177.8 mm
(7.00 in.)

139.7 mm
(5.50 in.)

Bolt Pattern

203.2 mm
(8.00 in.)

135.1 mm (5.32 in.)

36.3 mm
(1.43 in.)

36.3 mm
(1.43 in.)

135.1 mm
(5.32 in.)

23.0 mm
(0.91 in.)
diameter

203.2 mm (8.00 in.)

Model 249.32 Dimensions

Series 249 Rod Swivel Product Manual Introduction

21

Model 249.41 Dimensions

317.5 mm (12.50 in.)

314.5 mm
(12.38 in.)

241.3 mm (9.50 in.)

33.65 mm (1.325 in.)

241.3 mm (9.50 in.)

Footprint

For Actuator Rod

For Actuator Base

152.4 mm
(6.00 in.)

320.5 mm
(12.62 in.)

M52 x 2mm
(2-12 UN)
Torquenut

Adapter

Bolt Pattern

104.7 mm (4.121 in.)

109.5 mm (4.31 in.)

152.4 mm
(6.00 in.)

406.4 mm
(16.00 in.)

24.8 mm
(0.975 in.)
diameter

104.7 mm
(4.121 in.)

71.9 mm
(2.832 in.)

71.9 mm
(2.832 in.)

Model 249.41 Dimensions

Introduction

22

Series 249 Rod Swivel Product Manual

Model 249.42 Dimensions

346.2 mm
(14.34 in.)

355.6 mm
(14.00 in.)

279.4 mm
(11.00 in.)

34.8 mm
(1.37 in.)
diameter

279.4 mm
(11.00 in.)

For Actuator Rod

Footprint

For Actuator Base

206.4 mm
(8.125 in.)

250.1 mm
(9.875 in.)

29.2 mm
(1.15 in.)

230.1 mm
(9.06 in.)

206.4 mm
(8.125 in.)

339.7 mm
(13.375 in.)

2–12
Torquenut

Adapter

71.9 mm
(2.832 in.)

24.4 mm
(0.96 in.)
diameter

104.7 mm
(4.121 in.)

104.7 mm
(4.121 in.)

71.9 mm
(2.832 in.)

Bolt Pattern

Model 249.42 Dimensions

Series 249 Rod Swivel Product Manual Introduction

23

Model 249.51 Dimensions

406.4 m
(16.00 in.)

406.4 mm (16.00 in.)

298.4 mm (11.75 in.

298.4 mm
(11.75 in.

Footprint

43.9 mm
(1.73 in.)
diameter

For Actuator Rod

For Actuator Base

213.4 mm
(12.30 in.)

241.3 mm
(9.50 in.)

304.8 mm
(12.00 in.)

Bolt Pattern

122.1 mm
(4.806 in.)

81.6 mm
(3.212 in.)

3–12
Torquenut

Adapter

412.7 mm
(16.25 in.)

241.3 mm
(9.50 in.)

122.1 mm
(4.806 in.)

Thread
1-8 UNC 2B

81.6 mm
(3.212 in.)

Model 249.51 Dimensions

Introduction

24

Series 249 Rod Swivel Product Manual

Installation

Contents Mounting a Swivel 25

Mounting a Swivel

This section describes how to install the Series 249 Swivels.

Mounting for Angularly Applied Loads 26

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 are 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, and grade.

Mounting Bolt Size, Torque and Grade Requirements

ODEL MOUNTING BOLT SIZE MOUNTING BOLT TORQUE BOLT GRADE

M

SI METRIC U.S. CUSTOMARY N·MLBF·FT ISO SAE

249.12 M10 x 1.50 3/8-16 53 34 12.9 8

249.20 M16 x 2.00* 5/8-11* 230 160 12.9 8

249.23 M16 x 2.00 5/8-11 230 160 12.9 8

249.32 M24 x 3.00 1-8 780 680 12.9 8

249.41 M30 x 3.50 1 1/4-7 1600 1360 12.9 8

249.42 M30 x 3.50 1 1/4-7 1600 1360 12.9 8

249.51 M42 x 4.00 1 1/2-6 3200 2400 12.9 8

*If 1/2 in. or M12 bolts are necessary, hardened washers should be used under the heads of the bolts.

®

Before mounting the swivel, apply Molykote
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 recommended torque value. Continue
using this pattern to tighten the bolts to their final torque value.

Series 249 Rod Swivel Product Manual Installation

G grease, or equivalent, to the

25

Mounting for Angularly Applied Loads

Retaining

Stops

Retaining

Stops

Mounting for Angularly Applied Loads

If the swivel mounting surface is not perpendicular to the direction of applied
force, it may 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.

Mounting Bolt Tightening Sequence

The following figure shows the position of the retaining stops and the angle of
load application.

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 chart.

26

Installation

Series 249 Rod Swivel Product Manual

Mounting for Angularly Applied Loads

249.12

249

.

20

2

49.

23

2

49

.32

249.

4

1

2

49.42
2

49.

51

(degrees of rotation from the vertical

Angle of Load Application versus Maximum Load at Slip Point

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 249 Rod Swivel Product Manual Installation

27

Mounting for Angularly Applied Loads

Shear strength of retaining stops

(degrees of rotation from the vertical)

Minimum Shear Rating of Retaining Stops

28

Installation

Series 249 Rod Swivel Product Manual

Maintenance

Contents Swivel Bearing Backlash 29

Overview Maintenance for the Series 249 Swivels consist of periodic checks and, if

Swivel Bearing Backlash

Checking for Swivel Bearing Backlash—Observation Method 29

Checking for Swivel Bearing Backlash—System Response Method 31

Adjusting Backlash 31

Adjusting Models 249.12/.20/.23/.32 32

Adjusting Models 249.41/.42/.51 33

necessary, adjusting the backlash. 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.

Testing 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.

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

Series 249 Rod Swivel Product Manual Maintenance

29

Checking for Swivel Bearing Backlash—Observation

WARNING

WARNING

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.

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.

These methods will only detect large amounts of swivel bearing backlash. If the
backlash can be seen, heard, or felt, the swivels require adjustment.

30

Maintenance

Series 249 Rod Swivel Product Manual

Checking for Swivel Bearing Backlash—System

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.

Presence of Backlash During Load Reversals

Adjusting Backlash

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 subsections contain 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 249 Rod Swivel Product Manual Maintenance

31

Adjusting Models 249.12/.20/.23/.32

WARNING

M

249.12 34 25 Hex head bolt

249.20 110 84 Socket head cap screw

249.23 380 280 Socket head cap screw

249.32 920 680 Socket head cap screw

249.41 62 45 Superbolt Torquenut

249.42 62 45 Superbolt Torquenut

249.51 62 45 Superbolt Torquenut

Clamping Torque and Bolt Type

ODEL CLAMPING TORQUE BOLT TYPE

N·MLBF·FT

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 procedures, and do not exceed the
specified backlash adjuster clamping torque.

Adjusting Models 249.12/.20/.23/.32

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. Loosen the swivel bearing clamping bolt.

4. With a spanner wrench, turn the backlash adjuster counterclockwise 5 to 10
degrees (as viewed from the top of the clamping bolt). This will increase the
size of the gap in the swivel eye, and decrease the clearance in the spherical
bearing when the clamping bolt is tightened.

32

Maintenance

5. Tighten the swivel bearing clamping bolt to the specified clamping torque
shown in the table “Clamping Torque and Bolt Type.” The clamping torque
should always be the same regardless of the adjuster setting.

Note The backlash adjuster must be in contact with the surface of the

spherical washer when the clamping bolt is tight. When the adjuster is

Series 249 Rod Swivel Product Manual

loose, the bearing is clamped too tightly and the clamping bolt can fail in

Jackbolts

Main thread

Top Vi e w

Side View

Jackbolt

Torquenut

Hardened washer

Spherical washers

Swivel

fatigue. Find and correct the source of the problem before continuing.

6. Apply hydraulic pressure and check for backlash using the methods
described in “Checking for Swivel Bearing Backlash.”

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 the optimum backlash adjustment
setting. The optimum setting is determined by the performance
requirements of the testing system.

7. If unacceptable backlash is still observed, repeat Steps 1 through 6 until it is
eliminated.

Adjusting Models 249.41/.42/.51

The Model 249.41/.42/.51 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.

Adjusting Models 249.41/.42/.51

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.

Superbolt Torquenuts

If backlash is observed using the methods discussed in “Checking for Swivel
Bearing Backlash,” 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 actuator.

Series 249 Rod Swivel Product Manual Maintenance

33

Adjusting Models 249.41/.42/.51

CAUTION

Do not loosen the jackbolts on the Torquenut without following the
instructions in Step 3 of 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.

3. 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

.

4. 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).

5. With a spanner wrench, turn the backlash adjuster counter-clockwise 5 to 10
degrees (as viewed from the top of the Torquenut). This will increase the
size of the gap in the swivel eye, and decrease the clearance in the spherical
bearing when the clamping bolt is tightened.

6. 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 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).

7. Hand-tighten each jackbolt to ensure even seating of the main thread.

8. Using the torque wrench, tighten the jackbolts in the sequence shown in the
figure below to 35 N·m (25 lbf·ft).

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Maintenance

Series 249 Rod Swivel Product Manual

Adjusting Models 249.41/.42/.51

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
62 N·m (45 lbf·ft).

9. Apply hydraulic pressure and check for backlash using the methods
described in “Checking for Swivel Bearing Backlash.”

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 the optimum backlash adjustment
setting. The optimum setting is determined by the performance
requirements of the testing system.

10. If unacceptable backlash is still observed, repeat Steps 1 through 9 until it is
eliminated.

Note The backlash adjuster must be in contact with the surface of the

spherical washer when the Torquenut is tight. When the adjuster is
loose, the bearing is clamped too tightly and the clamping bolt can fail in
fatigue. Find and correct the source of the problem before continuing.

Series 249 Rod Swivel Product Manual Maintenance

35

Adjusting Models 249.41/.42/.51

36

Maintenance

Series 249 Rod Swivel Product Manual

m

MTS Systems Corporation

14000 Technology Drive
Eden Prairie, Minnesota 55344-2290 USA
Toll Free Phone: [phone]

(within the U.S. or Canada)

Phone: [phone]

(outside the U.S. or Canada)
Fax: [phone]
E-mail: [e-mail]
http://www.mts.com

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