WHAT IS THE MOELLER CLICK-LOC ADVANCED SELF-LOCKING DEVICE?
It is an external secondary locking feature which provides an
enhanced reliability and maintainability alternative to lockwire,
tab washers, cotter pins, deformed threads, locking elements,
or thread lock compound (e.g., "Locktite").
WHAT IS IT MADE FROM?
The standard material is Inconel 718.
HOW DOES IT WORK?
As the component is assembled, the CLICK-LOC engages usually within
the last two turns prior to seating. Once engaged, the flexible
beam fingers of the lockring act against the detent form of the
mating part to provide a unique ratcheting type prevailing torque
which is sufficient to prevent loosening from all known causes.
WHERE IS IT USED?
Most applications are critical components on or close to jet engines,
including fuel line coupling nuts, borescope plugs, drain plugs,
adjustable mechanical linkages, and engine mounts.
WHO ARE THE PRESENT USERS?
Customers using the CLICK-LOC include such industry leaders as GE Aircraft Engines, Pratt & Whitney, Rolls-Royce, Pratt & Whitney Canada, Allison, Allied Signal, Boeing, Lockheed Martin, Snecma, USAF and many more. The CLICK-LOC has been used in commercial and military aircraft and other applications since 1993.
IS IT REUSEABLE?
The CLICK-LOC is typically rated for 100-cycle reusability in applications
up to 600°F; from 600°F to 1200°F the typical reusability
rating is 50 cycles. Generally, the CLICK-LOC reusability exceeds the
service life of the component on which it is installed.
WHAT IF THE FINGERS BREAK OFF?
The fingers are an integral machined part produced by strictly
controlled manufacturing process and NDT procedures, the same
as the other critical engine parts we manufacture. The material
(Inconel 718) is tough and durable. There has never been
a reported case of a finger coming off inadvertently. However,
if it were to happen, the lockring would need to be replaced.
WHAT IF A FINGER IS DAMAGED?
The answer is the same as for other engine parts, i.e., what if
the fuel line is damaged? Damaged parts need to be replaced.
However, the CLICK-LOC is designed with a substantial safety margin
and there is a possibility, as determined on a case-by-case basis,
that the CLICK-LOC will provide adequate security until replacement
can be done. This is totally dependent on the extent of the damage,
the remaining prevailing torque which must be verified, and the
concurrence of both Moeller and the OEM design activity.
HOW MUCH DOES IT COST?
Pricing is dependent on part size, complexity, and the production quantity. Generally, the price
ranges from $50 to $200 per joint. This is the up-front acquisition
cost. In almost all applications thus far the CLICK-LOC becomes exceptionally
cost effective when Life Cycle Costs are considered.
CAN THE CLICK-LOC BE RETROFIT TO MY PRESENT HARDWARE?
Sometimes yes, sometimes no. This is dependent on many factors,
and also the cost effectiveness of retrofit versus replacement
must be considered. Thus far, our applications include some major
retrofit programs that are extremely cost effective.
WE ARE EXPERIENCING LEAKING FITTINGS. WILL THE CLICK-LOC FIX THIS?
If the leaking fittings are associated with the coupling nuts
loosening the CLICK-LOC will definitely fix it. If the nuts do not
loosen but leak anyway, the problem is in the sealing surfaces
and the CLICK-LOC will not fix it, but it will prevent it from getting
worse. Note: As a coupling nut loosens, the coupling looses
rigidity and can wear out quickly from vibration and the resultant
rubbing action at the sealing surfaces. Using the CLICK-LOC will help
prevent coupling wear.
DOES THE CLICK-LOC CHANGE THE FITTING TORQUE?
Yes. The CLICK-LOC adds some prevailing torque during the last two
or so turns immediately before seating. This can be compensated
for by several methods.
1) Note the prevailing torque the CLICK-LOC generates (i.e., 30 in-lbs.)
and add this to the standard tightening torque the fitting would
normally require (i.e., 300 in-lbs.) and tighten to sum total
(i.e., 330 in-lbs). This is the most accurate method of achieving
the standard tightening torque level. This method is called "torque
plus" and is widely used for self-locking crimp nuts.
CAN THE CLICK-LOC BE USED WITH ALL TYPES OF MATERIALS?
2) Another method is to add a constant (i.e., 30 in-lb.) to the
standard tightening torque. The CLICK-LOC is capable of generating
a predictable and consistent amount of prevailing torque cycle-to-cycle
and part-to-part. While this method is not as accurate as "torque
plus", it may be suitable.
3) If tightening is done by "wrench arc" or "nut
angle" methods, no change is required. This is a very accurate
method of preloading fluid fittings.
Yes, the CLICK-LOC is made from Inconel 718. Retrofit kits can be applied
to couplings made of virtually any material.
DOES THE CLICK-LOC REQUIRE ANY UNIQUE MAINTENANCE PROCEDURES?
No. Fluid fitting couplings and most plugs and fasteners are usually
lubricated with oil before tightening.
A light film of oil on the CLICK-LOC will extend its service life as
DO RETROFIT KITS CHANGE THE WRENCH SIZES?
Yes, generally the next 1/16" larger size must be used.
HOW DO I KNOW IF AN CLICK-LOC IS WORN OUT?
If a pronounced ratcheting feel is no longer evident, replace
the CLICK-LOC. This is indicative of severe wear, but this occurs well
before the prevailing torque diminishes so replacement can be
done prior to losing security. If properly serviced the CLICK-LOC should
not wear out.
HOW CAN I VERIFY THE CLICK-LOC IS FUNCTIONAL AND THE JOINT IS SECURE?
Visually look at the joint to be sure the fingertips are overlapping
the detent area. While this does not assure the joint is properly
torqued (neither does the presence of lockwire), it will tell
you the mechanic used a wrench to tighten the joint (lockwire
does not indicate a wrench was used), and the joint will not loosen.
Also, during servicing a positive ratcheting feel and/or measuring
the prevailing torque can assure proper function. Generally,
the CLICK-LOC will also produce a noticeable clicking sound as well.
WILL THE CLICK-LOC STILL WORK IF IT GETS OILY OR DIRTY?
Yes, lubrication is recommended for maximum service life. Dirt,
carbon build-up, and other contaminants do not significantly affect
HOW IS THE CLICK-LOC RETAINED ON THE MATING PARTS?
New components are typically retained by a controlled interference
fit, sufficient to provide a 500 to 1,000% safety margin over
the maximum forces that could be expected. Retrofit components
are generally sleeves that snap in place.
WHAT STANDARD OR SPECIFICATION DOES THE CLICK-LOC CONFORM TO?
There is no industry standard that applies to the CLICK-LOC because
it is a fairly new product in a field where nothing existed before. In lieu of an industry standard, performance criteria are specified
for each application.
HOW WAS THE CLICK-LOC QUALIFIED?
Initially, there was extensive lab testing (including vibration,
circular flexure, reusability, pressure and thermal cycling).
This was followed by qualification testing on AMT engines, then
in-flight service evaluations. It is important to note that
all CLICK-LOC components use virtually the same materials, beam geometry, and
locking configuration. Therefore, each new application additionally
substantiates all others. For more details about testing and substantiation please click
HOW DOES THE CLICK-LOC COMPARE TO COMPETITIVE DEVICES?
The CLICK-LOC is by far the most widely accepted secondary locking feature
for special applications such as those listed previously. No
other competitive product exists which meets all the original
USAF design criteria for self-locking fluid fittings (the CLICK-LOC
Recently some "one sided" designs have been introduced. They are called that because they do not require any locking component on the male threaded part. Instead these designs attempt to safety the fitting by locking the nut to the hose or tube of which it is part of. This is never done even with safety wire! The reason why is that when the coupling nut is tightened it has a tendency to impart a twisting force to the hose or tube on which it is installed. This is such a well known problem that many hose manufacturers design their hoses with a second hex behind the coupling nut (to allow another wrench to be used to minimize twist-up) and a stripe painted down the length of the hose to indicate the degree of twist-up that has occurred. Even with these precautions any twist-up at all means the hose or tube is constantly exerting a torsional force against the coupling nut, and it is in the CCW loosening direction. The "one sided" designs are inherently flawed because under conditions of tube or hose twist-up they become self loosening!
Unlike the "one sided" designs, CLICK-LOC actually locks the male and female threaded parts together. This is the way that safetying is to be accomplished in accordance with well established standards (see specifications AS567 and AS4536 for illustrations) and it is only way to positively prevent all loosening.
Finally, CLICK-LOC is the only readily retrofittable and repairable product
on the market. The CLICK-LOC is technically superior, affordable, reliable, and
flight proven in service in thousands of commercial and military aircraft. This is why CLICK-LOC is clearly the industry leader by a wide margin.
HOW RELIABLE IS CLICK-LOC
Please call us at 1-800-321-8010 or e-mail to discuss your specific applications.
Reliability data has been tracked. It's measured in the hundreds of millions of component flight hours. Please go to http://www.moelleraircraft.com/reliab1.htm to view the most recent data.
This product is protected by US and international patents