Flexural Pivot Brochure
The Free-Flex® Pivot — Infinite Life Flexures
Overview
The Free-Flex® Pivot is a frictionless, stiction-free bearing uniquely suited for limited angular travel. Made of flat, crossed springs supporting rotating sleeves, it is designed for applications that do not permit lubrication yet demand precise positioning and require infinite life. Originally patented by the Bendix Company in 1961, over eight million pivots have been put into service. The product line was purchased by the Riverhawk Company in 2004.
Key Highlights
Frictionless
No rolling or coulomb friction — better performance and repeatability
Stiction-Free
Resolution to the micro inch with predictable response
Infinite Life Cycle
Designed for fatigue life below the endurance limit
No Lubrication
Maintenance-free operation in any environment
Wide Temperature Range
Ambient range of -400°F to +1200°F
Vacuum & Radiation Ready
Operates in space vacuum with radiation resistance
Major Performance Characteristics
- High radial stiffness and high axial stiffness
- Frictionless, stiction-free operation
- Lubrication and maintenance not required
- Not susceptible to false brinelling
- Electrical continuity across the pivot
- Infinite cycle life (see life curves)
- Low hysteresis and low center shift
- Self-centering with no rubbing surfaces
- Contaminant tolerant
Evolution of the Free-Flex® Pivot
The flexural pivot technology has passed through several leading engineering organizations over six decades: Bendix (1955), Allied (1982), Allied Signal (1988), Lucas (1990), Lucas Varity (1996), TRW (2000), Goodrich (2002), and Riverhawk (2004). This lineage ensures continuous refinement and flight heritage across aerospace, defense, and scientific programs.
Standard Materials & Custom Options
The standard Flex Pivot is made from 410 and 420 stainless steel. Custom options are available in a variety of alternative materials. Custom features can be added to standard models, including flanges, grooves, flats, special lengths, and custom spring rates. Riverhawk is fully capable of special designs and sub-assembly integration, with complete testing equipment for fatigue, center shift, torsional spring rate, concentricity, roundness, radial/axial spring rate, and static load testing, plus a full metallurgy lab.
Industries Served
- Defense / Military
- Optics & Photonics
- Aerospace
- Material Handling
- Energy / Environment
- IT and Communications
- Semi-Conductor
- Robotics
Typical Product Applications
- Scanning Mirrors
- Fast Steering Mirrors
- Optical Assembly Mounts
- Precision Welders
- Gimbal Ring Mounts
- Vibration Sensors
- Instrument Indicating Heads
- Aircraft Flight Controls
Flexural Pivot Brochure — PDF
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