HIGH CYCLE TORQUE TEST OF CLICK-LOC&#153 SELF-LOCKING FLUID FITTINGS

1.0 PURPOSE

1.1 The purpose of this procedure is to describe the high cycle torque testing of self-locking fluid fittings equipped with the Moeller Click-Loc&#153 locking device.

2.0 SCOPE

2.1 This procedure is applicable to all self-locking fluid fittings which use the subject lockring (finger)/detent sleeve locking device (ref. U.S. Patent 5,083,819). This procedure applies to both the integrally machined and universal type of locking devices. It is intended as a general guide. Specific customer requirements such as base fitting type, lubricant, NDT, and temperature cycling may be added as appropriate.

3.0 APPLICABLE DOCUMENTS

3.1 The following documents are applicable to this procedure:

High Cycle Torque Test Data Sheet

4.0 EQUIPMENT

4.1 The following equipment is necessary to perform the testing:

Rigidly mounted machinist’s vise
Calibrated Snap-On Tools 3/8" drive dial type torque wrench, 150 in-LB
Appropriate sockets or crowfoot wrenches
Commercial grade waxy lubricant such as Safety-Draw 722

5.0 PROCEDURE

5.1 The test shall be set-up and performed per the following steps:

5.1.1 Testing shall be performed on Click-Loc&#153 self-locking components assembled on fluid fittings or test specimens representative of fluid fittings or representative of the intended production application.
5.1.2 Mount one part of the fitting in the vise and tighten securely. It is usually most convenient to mount the male fitting in the vise. For the purpose of explanation we will assume the male fitting is clamped in the vise and the coupling nut is being assembled onto it.
5.1.3 Assemble the nut and ferrule onto the male fitting and screw together by hand until the locking feature begins to engage. Prior to engagement the fitting parts should be completely free running with no significant drag (ref – less than 2.5 in-LB). If significant drag is felt then something is wrong and it must be corrected prior to testing. Possible causes include distortion caused by overtightening the vise, defective or damaged threads, and excess dry film lubricant or plating on threads.
5.1.4 Once free running assembly has been verified disassemble the nut and apply a light film of waxy oil to the threads, the pressure face of the nut/ferrule interface, and the detents.
5.1.5 Re-assemble the nut and screw together until the locking device begins to engage. Use a wrench and continue to tighten until seated. Once the locking device has engaged there should be a pronounced ratcheting (click-click-click) feel while tightening. Once fully seated the end of the locking fingers should overlap the detents by .130 inch nominal. There is considerable tolerance allowed for the overlap dimension but in no case neither should the overlap be less than .060 inch nor should the fingertips extend past the detents. There is no need to apply tightening torque after seating, as it does not affect the locking device performance.
5.1.6 Loosen the nut just enough to relieve any seating forces. This is usually only about 15 degrees maximum, or 2 clicks.
5.1.7 Stop loosening and use the torque wrench and appropriate socket or crowfoot wrench to measure the torque necessary to resume loosening. The dial needle on the torque wrench will oscillate as the locking device clicks. Observe and record the peak torque value obtained while loosening the nut an additional 90 degrees approximately. Be careful not to loosen the nut too quickly or the ratcheting effect might cause the needle to bounce resulting in erroneous readings.
5.1.8 Continue to loosen the nut until the locking device is completely disengaged and the nut is once again free running. It is not necessary to completely disassemble the nut, as this does not affect the locking device performance.
5.1.9 Repeat steps 5.1.5 through 5.1.8 until the required number of cycles have been achieved.
5.1.10 Upon completion of the required number of cycles completely remove the fitting components and clean as necessary. Observe the condition of the fingertips and detents and report any severe wear or damage.

6.0 ADDITIONAL NOTES

6.1 The nut/ferrule interface (the pressure faces) are the most highly loaded surfaces when tightening a fluid fitting. If these surfaces are not adequately lubricated wear and galling will occur which will contribute to the torque value observed when the fitting is tightened. The objective of tightening is to apply sufficient clamping forces to make a seal and cause enough preload to prevent loosening. Any torque component attributable to wear at the pressure faces will lessen the clamping forces applied to the threads and sealing surfaces
6.2 The Safety-Draw 722 waxy oil is specified in this procedure because it is typically used in fastener applications and provides a consistent test parameter for multiple locking device applications. In order to obtain data representative of service conditions the OEM specified lubricant should be used in place of Safety-Draw 722.
6.3 If the fitting is being used in areas exposed to temperatures in excess of 400 degrees Fahrenheit it might be useful to include a heat soak every cycle. This is usually done after seating the nut. The nut is broken loose and the torque measured after completion of the heat soak and cooling back to room temperature. Additionally, following the torque measurement the nut must be completely removed and lubricant reapplied every cycle.

Note: This is a rough draft of a proposed MP procedure.

It is released for reference purposes only.

Copyright 01/04/00 Moeller Mfg.