Titanium LHP® Lockbolt

Aerospace : Fastening Systems : Lockbolt Fastening Systems : Titanium LHP™ Lockbolt

Titanium LHP™ Lockbolt

LHPL7SC, LHPL8SC, LHPL9SC, LHPL9SP & LHPL12SP
 

Huck's lightweight (LHP)  Lockbolt fastener is a high-strength, lightweight, aerospace fastener intended for use in composite material applications. Easily the most cost-effective aerospace fastener available for fastening composite material. The LHP can help reduce aircraft weight due to its all Titanium construction and improved fastener installation time due to its pull action tension/tension installation method.
 
The (LHP) fastener is a modified version of the HUCKCOMP®  fastener incorporating the simular design features. The fastener has large bearing heads and accompanied with large bearing flanged based Titanium collars that provide a high clamp load distributed over a larger area so as not to cause material damage. This large bearing hi-clamp force gives the LHP fastener the ability to achieve joint integrity and enhanced fatigue performance.
 
The LHP for composite applications is the newest version of the Huck Lockbolt family, which has been used on aircraft for over 50 years. Unlike threaded fasteners, Lockbolts install rapidly and cannot vibrate loose. Their unique design assures predictable consistent clamp force.
 
Design Features
 
The LHP Lockbolt fastener is offered in LHPL8SC with 100° MS24694 flush heads, LHPL7SC 100° MS20426 flush heads, LHPL9SC 130° low profile large bearing flush heads, LHPL9SP low profile large bearing protruding heads, and LHPL12SP intermediate large bearing protruding heads. All LHP fasteners are 6Al-4V Titanium at 95 KSI shear strength.
 
Collars for the LHP fastener are 3AL-2.5V Titanium, which provides an all Titanium fastener installation, which is compatible with graphite epoxy type composite materials
The LHP Lockbolt features lock grooves with a tapered root diameter and variable pitch. A larger volume of collar material flows into the locking grooves at the beginning of the of the installation sequence. This gives the fastener its greatest tensile strength where it is most crucial during swaging of the collar so that a high clamp force can be developed with out loss of strength during collar swaging/extrusion resulting in a high residual clamp and high ultimate tensile. The 60° included angle of the locking groove has a 20-degree pressure flank angle, which serves as a platform for retaining the high clamp load generated during collar installation.
 
Cost effective Features
 
Sloped surface installations
The LHP fastener can be installed on sloped surfaces up to 5° on the collar side of material being fastened.

With this feature heavy, costly self-aligning washers and special nuts are not required. Inventory costs as well as structural weight is reduced. Fewer parts to handle translate into greater labor efficiency.
 
Extended grip range The LHP fastener has a usable 3/32" grip range, which reduces inventory, and installation errors that are common when using conventional 1/16" grip range fasteners. The extended grip range makes the LHP fastener more forgiving if the installer needs a fastener just over or just under the recommended grip which often happens when fastening composite materials due to variations in material thickness and use of liquid shim materials.
 
Self-Sealing
The labor-intensive job of over-coating each fastener or the use of heavy, costly sealing nuts is eliminated with the LHP fastener. Annular grooves on the pin forms a series of separate barriers to prevent fuel seepage. Fay surface sealant flow during installation due to high clamp load ensures reliable fay surface sealing.
 
Vibration Resistance Because the LHP fastener uses annular instead of helical grooves and installations are made with a tension/tension action rather than a torque/tension action there is no path for loosening in a vibrator environment.
 
Low Collar-side Clearance
The installed height profile of the LHP fastener is significantly lower than that of threaded fastener. Its low collar-side profile enables it to fit in tight space areas.
 
Minimal Rework
Because the LHP fastener is a pull-type installation there is no surface damage often associated with torque type fasteners resulting in no surface damage.



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