• Frictionless• Stiction-Free• No Lubrication
Required• Maintenance-Free• Infinite Cycle LifeFLEXURAL PIVOTSSPECIFY THE ORIGINALThe Free-Flex ® Pivot
The Free-Flex® Pivot is a simply packaged, compact
and easily installed limited rotation bearing withpredictable and repeatable performance. The pivot
is made of flat, crossed springs supporting rotating
sleeves. Originally patented by the Bendix Company in
1961, to date over eight million pivots have been put
into service. The product line was purchased by
the Riverhawk Company in 2004.
The Free-Flex® Pivot is a frictionless, stiction-free bearing uniquely suited for limited angular travel. Flex pivots
are designed for applications that do not permit lubrication yet demand precise positioning and require infinite
life. Along with a wide range of industrial applications,additional applications include guidance systems formissiles, scanning mirror assemblies for bothsatellites and ground applications, jet engine fuelcontrol, and vibration sensors. Flexural pivots are theproduct of choice any time reliable, predictable rotationis needed.

A variety of pivot sizes and ratings are available in bothcantilevered (Series 5000) and double-ended (Series 6000)
designs. We are also fully capable of special designs andhave all the testing equipment necessary to examine every
mechanical property of our flexural pivots to include:
fatigue testing, center shift testing, torsional spring
rate testing, concentricity, roundness, radial / axial spring
rate and static load testing. We also have a full metallurgy
lab to perform a metallographic analysis.
Flexural pivots are made from 410 and 420 stainless steel
for standard construction. Special materials have included
Custom 455 Stainless, Inconel 718, Titanium andMaraging Steel. Special configurations have included
flanges, grooves, flats, special spring rates, special lengths
and gold plating.

Evolution of theFree-Flex ® Pivot• Bendix 1955
• Allied 1982

Major Performance
Characteristics• Allied Signal 1988
• Lucas 1990

• High radial stiffness• Lucas Varity 1996

• High axial stiffness• TRW 2000

• Frictionless• Goodrich 2002

• Stiction-free• Riverhawk 2004

• Not susceptible tofalse brinelling

Cutaway of Double-Ended Design• Low hysteresis• Low center shift

Additional
Characteristics• Exceptional repeatability• Radiation Resistance• Predictable performance• Low Thermal drift• Lubrication not required• No Rubbing surfaces• Maintenance not required• Contaminant tolerant• Electrical continuity• Operates in vacuum of space• Infinite cycle life

• Self – centering(See life curves)• Resolution to the micro inch range• Ambient temperature range

˚

˚of - 400 F to +1200 F

Cutaway of Cantilevered Design

Visit our website at: www.flexpivots.com

Dimensions & Characteristics
Typical Units
NominalOutsideDiameter(Inch)

Catalog
NumberLoad Capacity (Pounds)

0.12500.15620.18750.25000.31250.3750

0.50000.62500.75001.0000

Load Capacity (Pounds)

Load At Centerof “A”.

Load At Centerof “C”.

See Note (1)See Note (1)Torsional
SpringRatein - lb
DegreeSeries
6000

Series
5000
L

D+0.00-0.0005

Catalog
NumberA

L

DoubleEnded(size-type)Vc

Vt

6004-400

28.0

28.0

6004-600

17.7

25.0

Cantilevered(size-type)Vc

Vt

5004-400

25.5

25.5

5004-600

8.9

13.0

5004-800

0.97

3.7

6004-800

2.20

4.75005-400
5005-600

39.5

39.56005-400

44.0

44.0

13.8

20.06005-600

27.6

39.0

5005-800

1.50

6.0

6005-800

3.50

7.4

5006-400

56.0

56.0

6006-400

63.0

63.0

5006-600

19.8

28.0

6006-600

39.6

56.0

5006-660

12.2

20.2

5006-800

2.1

8.0

6006-800

4.99.0

5008-400

101.0

101.0

6008-400

113.0

113.0

5008-600

35.5

51.0

6008-600

70.7

100.0

+/- 0.003 +/- 0.005
0.200

0.250

0.300

0.095

0.120

0.142

B

+/- 0.003 +/- 0.005

C+0.005-0.015See
Note (2)0.0140

0.200

0.045

0.085

0.00170.00020.0279

0.250

0.057

0.110

0.00350.00040.0473

0.300

0.067

0.130

0.00570.0037

0.400

0.190

5008-800

3.7

14.5

6008-800

8.5

19.0

5010-400

158.0

158.0

6010-400

176.0

176.0

5010-600

55.0

79.0

6010-600

110.0

156.0

5010-800

5.8

23.0

6010-800

14.0

29.0

5012-400

228.0

228.0

6012-400

253.0

253.0

5012-600

80.0

114.0

6012-600

159.0

225.0

5012-800

8.4

32.8

6012-800

19.8

42.0

5016-400

403.0

403.0

6016-400

450.0

450.0

5016-600

141.0

202.0

6016-600

283.0

400.0

5016-800

14.6

58.0

6016-800

35.4

75.0

5020-400

634.0

634.0

6020-400

703.0703.0

5020-600

222.0

317.0

6020-600

442.0

625.0

5020-800

23.0

93.0

6020-800

55.0

117.0

5024-400

910.0

910.0

6024-400

1013.01013.05024-600

318.0

455.0

6024-600

636.0

900.0

5024-800

33.0

130.0

6024-800

78.0

169.0

5032-400

1620.01620.06032-400

1800.01800.05032-600

567.0

815.0

6032-600

1131.01600.05032-800

60.0

236.0

6032-800

141.0

300.0

0.500

0.600

0.800

1.000

1.200

1.600

0.238

0.285

0.380

0.475

0.570

0.770

0.00070.1141
0.400

0.090

0.175

0.01430.00180.2234

0.500

0.112

0.220

0.02860.00360.3840

0.600

0.135

0.265

0.04800.00580.9080

0.800

0.180

0.355

0.11340.01421.8500

1.000

0.225

0.445

0.23210.0295
3.1800

1.200

0.270

0.535

0.39800.05007.5200

1.600

0.370

0.735

0.93900.1175(1) Pounds at zero deflection based on pure radial load. When the load is applied directly through a single spring, multiply capacity shown by 0.707.
(2) At zero load.

• Standard Materials:Pivot Body: AISI 410 or AISI
420 corrosion-resistant steel.
Flex elements: AISI 420
corrosion-resistant steel.
Brazed Construction.
• Tighter Diameter
Tolerance:
If a tighter diameter toleranceof (+0 / -0.0002) is required,specify T2 after the catalog
number.

• Torsional Spring Rate:
Torsional Spring rates aregenerally within +/- 10% orless of the nominal values,
however spring rates thatare 0.0018 lb-in/degree orless may have significantly
higher tolerances.

• General:
The correct pivot for a
specific application can beselected only after
determination of required
angle of deflection, load,
and life expectancy asthese are interdependent.
When unusual environments or multiplane loading
conditions exist consult
Riverhawk.

• Welded Construction:
Welded construction pivots
are available. Consult
Riverhawk for applicationengineering.

www.flexpivots.com

Cycle Life Curves
400 Type Pivot Bearing Loaded in Compression (Vc)
Factor of Safety = 1.0
35,000 Cycles

Riverhawk Recommends
Electron Beam Welded
Construction for Pivots
Loaded Beyond This Point+/- 6
200,000 Cycles+/- 5+/- 4

Infinite Life+/- 3+/- 2

Cantilevered (5000 Series)
Double Ended (6000 Series)+/- 1+/- 001020304050607080

90+/- 7

Deflection Angle (Degrees)

Deflection Angle (Degrees)+/- 7

Deflection Angle (Degrees)

Cantilevered (5000 Series)
200,000 Cycles

Double Ended (6000 Series)

Infinite Life

010203040

50

60708090

200,000 Cycles+/- 4

Infinite+/- 3+/- 2
Cantilevered (5000 Series)+/- 1

Double Ended (6000 Series)

0102030

40

5060

7080

Applied Radial Loadx 100 = %Vt
Radial Load Capacity

90+/- 11

Cantilevered (500035,000 Cycles
200,000 Cycles+/- 10+/- 9

Double Ended (6000 Series)

Infinite Life+/- 8+/- 7+/- 6+/- 5+/- 4+/- 3+/- 2+/- 10102030405060708090

Applied Radial Loadx 100 = %Vc
Radial Load Capacity

Applied Radial Loadx 100 = %Vt
Radial Load Capacity

800 Type Pivot Bearing Loaded in Compression (Vc)
Factor of Safety = 1.0

800 Type Pivot Bearing Loaded in Tension (Vt)
Factor of Safety = 1.0

Cantilevered (5000 Series)
Double Ended (6000 Series)
200,000 Cycles

Infinite Life

1020304050607080
Applied Radial Loadx 100 = %Vc
Radial Load Capacity

90100100600 Type Pivot Bearing Loaded in Tension (Vt)
Factor of Safety = 1.0+/- 12+/- 0100+/- 28

35,000 Cycles

0+/- 5+/- 1335,000 Cycles

Deflection Angle (Degrees)

Deflection Angle (Degrees)
Deflection Angle (Degrees)+/- 28+/- 26+/- 24+/- 22+/- 20+/- 18+/- 16+/- 14+/- 12+/- 10+/- 8+/- 6+/- 4+/- 2+/- 0

600 Type Pivot Bearing Loaded in Compression (Vc)
Factor of Safety = 1.0

Riverhawk Recommends
Electron Beam Welded
Construction for Pivots Loaded
Beyond This Point35,000+/- 6+/- 0100

Applied Radial Loadx 100 = %Vc
Radial Load Capacity+/- 14+/- 13+/- 12+/- 11+/- 10+/- 9+/- 8+/- 7+/- 6+/- 5+/- 4+/- 3+/- 2+/- 1+/- 0

400 Type Pivot Bearing Loaded in Tension (Vt)
Factor of Safety = 1.0

100

Cantilevered (5000 Series)+/- 26

Double Ended (6000 Series)+/- 24+/- 22

35,000 Cycles+/- 20200,000+/- 18+/- 16

Infinite+/- 14+/- 12+/- 10+/- 8+/- 6+/- 4+/- 2+/- 0010203040506070

Applied Radial Loadx 100 = %Vt
Radial Load Capacity

8090100

Flexural Pivot Applications• Gimbal Ring Mount:

The Free-Flex® Pivot isparticularly suited foromnidirectional applications. Also, the lack oflubrication permits operation in a hard vacuum. The
pivot can operate at higher
temperatures than otherbearings and provides a
relatively constant opposing spring force. Thus theactuator can be sized toaccommodate only theforce required to position
the rocket motor without
Gimbal Ring Mount
having to consider highfriction caused by spacewelding.

• Scanning Mirror:

No friction andsymmetrical springs
allow smooth motion
at the natural frequency,with low input required tosustain the oscillation.

• PerpendicularMirror:

Four or eight Free-Flex®
Pivots used in a parallelogram will maintaina mirror or other optics
perpendicular to any surface for applications that
require lateral motion.

Perpendicular Mirror• Seismic Vibration
Amplitude Sensor:
Free-Flex® Pivots areused as a damping
system. A transducer
converts the motion of
the sensor base to a
proportional signal.

Seismic Vibration
Amplitude SensorScanning Mirror• Weigh Station:

This represents anautomatic fillingmechanism which
controls the quantities
of materials packaged.

• Scale:After selecting the proper
pivot it is possible todesign a scale that has
no deflection in radial
direction, all motion of thesystem is purely rotational.

Weigh Station• Throttle Linkage:

Scale• Vibration
Accelerometer:

An accelerometer has
to endure billions of cycles
in its sensing lifetime. TheFree-Flex® Pivot is ideal
for this application as it
can provide infinite life
without maintenance.
Because the pivot requires
no lubrication, anextremely clean instrument
is possible.

Vibration
Accelerometer

Pivots selected for
different throttle systems
are tailored to performance requirements forthe particular application.
For instance, we haveaerospace applications
where high temperaturestability is as much a
selection factor as are nolubrication and contamination tolerance. For
industrial applications,pivot selection often
permits elimination ofThrottle Linkage
assembly parts andresults in a cost reduction.

These illustrations are solely for the purposeof stimulating the designer in the application ofFree-Flex® Pivots. No representation or warrant
is made that the specific devices depicted inthese illustrations may be manufactured, usedor sold without infringing patents of others.

Special Pivot Designs
Over the years we have mademany pivots that are outside therealm of our standard product.
Such designs have included:
longer lengths, flanges for
mounting, tailored torsional andradial spring rates, grooves foradhesive mounting and flats forset screw mounting. We are fully
capable of special designs andsub-assembly integration.

Mission Statement
Our mission at Riverhawk is a
mission of desire – every productRiverhawk makes will raise thestandard for each and every productthat follows. We will be the quality
standard by which the industries
we serve measure products andservices. We will accomplish this byusing dedicated, highly technicallytrained staff, the best machinery,
and the finest raw material. We will
do this not by policy decree but by
personal desire to excel.

215 Clinton Road • New Hartford, New York 13413
Phone: (315) 768-4855 • FAX: (315) 768-4941
For more information, log onto our website: www.flexpivots.com
or email us at: info@riverhawk.com