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ACT® RING

ADVANCED CONCEPT T-RING SEALS

Using FEA (Finite Element Analysis) and expertise in seal design, Greene, Tweed has taken the concept behind our renowned AGT® seal, optimized the design of the elastomer and anti-extrusion rings, and developed an Advanced Concept T-ring (ACT).

The ACT® ring is designed with converging sides in order to promote lubrication for reduced friction and wear, with an apex for force concentration under low-pressure conditions to optimize sealing. The design also enhances oil film passage upon the retract stroke for lubrication of the apex of the elastomer. Our in-house tests demonstrate service life increases by as much as 30 percent over some alternative seal designs.

FEATURES & BENEFITS

  • Improved stability in gland, resulting in reduced stress in the elastomer for enhanced sealing performance
  • Specially tapered elastomer side wall design reduces friction and promotes efficient seal lubrication ultimately leading to longer seal life
  • Hydromechanically activated, anti-extrusion rings for enhanced extrusion protection at all sealing pressures
  • The wide static footprint of the “T” geometry cross-section eliminates spiral failure
  • Retrofits existing MIL-G-5514/AS4716 and AS4832 glands
  • Metric series available for metric-sized designs

APPLICATIONS

  • Accumulators and reservoirs
  • Actuators (e.g., door actuators)
  • Flight controls (e.g., spoilers, rudders, aileron, etc.)
  • Landing gear actuator subsystems (e.g., end caps and static seals, etc.)
  • Landing gear spare dynamic seals
  • Landing gear dynamic seals
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ACT® CONFIGURATIONS

For pressures up to 4,000 psi (276 bar), we recommend standard diametrical clearances per MIL-G-5514/AS4716, providing proper gland lengths and materials are selected.

 Gland Dimensions

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ACT RING OPTIONS

“Staged” and “Split-Lock” Anti-Extrusion Ring Set
It is possible within wide-base gland arrangements to stage two different anti-extrusion ring materials on either side of the elastomeric sealing stem in order to accommodate high acceleration and pressure rates. The “softer” in-board PTFE material will protect the elastomer from abrasion and nibbling while the higher modulus out-board anti-extrusion ring performs the required anti-extrusion function.

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Staged rings can also be provided with our patented “split-lock” design. Each independent scarf-cut ring is interlocked along the radial face to simulate a one-piece continuous or endless antiextrusion ring. This allows for ease of assembly. The ring halves are dovetailed together, allowing the ring set to expand—“open”—for easier assembly than typical piston-type glands. This produces a stable ring within the gland that will not dislodge and become sheared during a blind assembly or with rotational motion typical of threaded end caps. Locked rings are ideal for field repair of landing gear shock struts.

Note: For rod-type assemblies the gland must be open ended, permitting the
locked ring sets to be placed down in the gland.

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 Radiused “T” Design
ACT® ring assemblies are designed with a transition radius between
the sealing stem and the extending flanges of the elastomer. The
mating corner radius in the anti-extrusion completes this unique
feature, thus reducing the tensile stresses within this region and
prolonging the life of the seal.t-rings-act-ring-image1“Flash Free” Option
Typical O-ring and generic “T” rings are molded with a parting line around the critical ID and OD sealing surfaces. This inherent interruption on the contact surface can lead to bypass seepage when sealing low molecular weight gases and liquids in low-pressure accumulator/reservoir applications. To combat this Greene, Tweed offers a flash free ACT ring.

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*Note: The ID of the flash free option cannot be less than 0.422 in.

 Metric Designs
The ACT metric ring features the same design characteristics and expected performance as the standard ACT ring, but it was developed for glands designed to metric standards. The dimension tables for the ACT metric ring piston and rod glands are found in a table on pages 6 – 9.

ACT® PART NUMBERING SYSTEM

The part numbering system requires the use of the material designator tables found on the next page. For nonstandard designs contact GT engineering.

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ACT PART NUMBERING SYSTEM (METRIC SEALS)

The part numbering system requires the use of the material designator tables found on the next page. For nonstandard designs contact GT engineering.

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Contact your local Greene, Tweed representative for specific recommendations to suit higher performance requirements.

 

Material Designator Tables
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ROD DIMENSIONAL INFORMATION (METRIC)

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Rod dimensional information continued
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PISTON DIMENSIONAL INFORMATION (METRIC)

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Piston dimensional information continued

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