Vibration of a Retaining Ring / E-Clip
Vibration of a Retaining Ring / E-Clip
(OP)
I am working a design that has jack screws - basically a grooved screw with an E-clip retaining ring for captive purposes. The design will undergo pyro shock and random vibe, so there is some worry that the E-clip will vibrate out of the groove on the screw.
Has anyone experienced E-clips coming out of their grooves due to shock or vibe?
I believe a circlip / external snap ring might stay in place better, but that is only an intuition. Also the screw that is retained is quite small (#4 = 0.112 in major diameter) and I haven't found any circlip style retaining rings down to that size.
Thoughts?
Has anyone experienced E-clips coming out of their grooves due to shock or vibe?
I believe a circlip / external snap ring might stay in place better, but that is only an intuition. Also the screw that is retained is quite small (#4 = 0.112 in major diameter) and I haven't found any circlip style retaining rings down to that size.
Thoughts?





RE: Vibration of a Retaining Ring / E-Clip
Doug
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
They recommended I do my own testing, which basically has me back at square one. I think I will adjust my design to try to prevent the retaining ring from being able to come off the shaft by reducing the gap between the clip and the surrounding clearance bore.
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
Needle retention in Slide type carburetors come to mind, I think.
Item 5, 6, 7, 8, and 9 here -
http://www.sudco.com/Diagrams123/expvm018.gif
or items 6 > 10 here -
http://www.sudco.com/Diagrams123/expvm.gif
view of clip on the needle 2:10 here -
http://www.bikebandit.com/aftermarket-parts/motorc...
for some reason all the pictures of the slide I found on line show the underside, not the top where the shallow counterbore is. ( If I recall correctly )
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
tbuelna: Thanks for your input. This is an aerospace application so your experience is relevant. I think a spiral ring is in order, but let me ask you for some clarification - do you mean that a spiral retaining ring would be acceptable for a travel stop on a lead screw? or do you mean only that a spiral ring would be acceptable for retaining the screw in place within the assembly?
RE: Vibration of a Retaining Ring / E-Clip
Ultimately, the main consideration when deciding what type of arrangement to use for your shaft stop is the level of fault tolerance required for your application. For aircraft mechanical systems the situation you describe would usually require a design providing single fault tolerance. This means the shaft retaining device must have two independent methods of retention. This is the only type of retaining ring I know of that would fulfill this requirement, but I don't think it is available in the small size you need.
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
RE: Vibration of a Retaining Ring / E-Clip
The screw is inserted through the PCB (green) and secured in place with an e-clip. The PCB is mated to the other PCB by turning the screws which pulls the boards together and mates their connectors. When the screws are reversed, the clips pull the cards apart. If the clips weren't there, the screws would come out and the boards would still be mated.
Does that make sense?
RE: Vibration of a Retaining Ring / E-Clip
I don't know if it is a good idea, but I do know that it is not a frequently used one. At least suppliers like Keystone don't mention the screws and snap rings that would be used, and Keystone would have them if there was a demand.
If the separation loads are high, then the should only be one screw in the center of the connector to prevent binding the connector on install or removal. I tried to find some examples, but didn't spend more than a few minutes with the Amphenol Aerospace connectors website, one place I expect to find self-jacking connectors.
RE: Vibration of a Retaining Ring / E-Clip
I think the solution has been converged on. The E-clip was changed to be a "heavy duty" version which has a larger OD and higher spring force keeping it in place on the groove. The larger OD of the E-clip reduces the clearance between the C'bore and the clip. The tight C'bore physically prevents the clip from working itself out of the groove. See the attached image. Note that in the image, the PCB and washers are hidden and the receiving piece with the tapped hole and C'bore is cut-away to show the detail.
Case closed. Thanks for the input everybody!
RE: Vibration of a Retaining Ring / E-Clip
Since the extraction function provided by the screws is not necessary for normal operation, it does not require functional fault tolerance. The only safety issue is making sure all parts of the device (such as the E-ring) are captured so they cannot escape and create a jamming or shorting hazard. In this regard, the arrangement shown in the first sketch would probably be acceptable.