Product category:
Fasteners, threaded and non-threaded
News Release from: Moeller Manufacturing | Subject: FlexThread
Edited by the Engineeringtalk Editorial
Team on 25 September 2002
Locking device keeps constant torque
with re-use
Standard and specialised plugs and other products incorporating the FlexThread locking device are available from Moeller Manufacturing.
The self-locking methods used for external threads on parts such as plugs and various sensors have previously consisted of embedded deformable plastic or soft metal locking elements Plastic locking elements are suitable only in low-temperature applications
This article was originally published on Engineeringtalk on 25 Sep 2002 at 8.00am (UK)
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Soft-metal locking elements can tolerate higher temperatures but thread galling can be a problem.
In both cases the reusability is low.
Each time the part is installed and removed (each "cycle") the locking element wears, and the locking torque drops every cycle until the locking element is worn out and the part must be replaced.
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Typically, the useful life of parts with these types of locking elements is only about ten cycles or less.
Additionally, as the locking torque drops rapidly from cycle-to-cycle, there is the possibility that a part with marginal torque during installation will check below the service limits during the subsequent removal and reliability will be compromised.
Due to the low reusability and poor reliability of these designs, additional means of securing the parts are necessary for critical applications.
These other means include lock washers, tab washers, safety wire, thread locking compounds, and cotter pins.
These all improve reliability but unfortunately they do so at the expense of maintainability.
The FlexThread design incorporates an active thread-locking feature into the standard threadform.
This active thread is highly flexible, floating and self-centring.
It distributes the locking torque over a large part of the mating thread so wear is negligible.
The result is that FlexThread delivers up to 100 cycles reusability, and more importantly it delivers consistent torque from cycle-to-cycle.
This combination of exceptional reusability and consistent torque provides superb reliability as well as ease of maintenance.
The FlexThread feature is made of a high-strength and wear-resistant nickel alloy and it tolerates temperatures that would vaporise other locking elements.
FlexThread parts do not require any special tools or training and they can be used in almost any standard threaded hole or port.
Best of all, there is no need for washers, wires, cotter pins or anything else.
Standard and specialised plugs and other products incorporating the FlexThread locking device are available from Moeller Manufacturing.
Moeller FlexThread plugs have been used in military and commercial aircraft for over 10 years.
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