Meaning of the expression "positively attached" 1

[alfredoborba]

What is the meaning of "positively attached", referring to a wheel assembled in a shaft?

Thanks for any help!

 

[kingnero]

you'd better ask the person who spec'd that, but I'd say besides a keyway or a press fit there should be something else that holds the wheel in place, preventing it from falling off...
like lockwire, threaded, pinned, castle nut + pin, ...

 

[MintJulep]

It's most likely just superfluous specification language, and no one on the customer side is really clear about what it means either.

So attach your wheel consistent with the other performance and maintenance requirements and when you get to design review state "I'm positive that this wheel is attached."

 

[rb1957]

i would say it means that there needs to be a physical linkage between the parts (fasteners, maybe keyway) rather than an interference fit.

 

[Latexman]

Language, writing, and clear communication is much more difficult to attain for me than the Engineering. For example, what comes to mind when you imagine "a wheel assembled in a shaft"? That, is much more perplexing than "positively attached" to me.

Good luck,
Latexman

 

[rb1957]

i assumed a typo ... particularly as "i" and "o" as adjacent keys.

 

[btrueblood]

Hmm. I think I'll use the phrase "negatively attached" the next time I write a dis-assembly report.

 

[tomwalz]

Tom’s Rules (He is a cynical old man who lost a lot of money before he learned these rules.)

1. Verbal communication is maybe 25% effective.

2. Written communication with drawings in an agreed upon format, properly rendered, may hit 90% effective.

3. Neither rule is 100% true but either rule is better than thinking the communication is 100%

P.S. I like the image of a wheel in a shaft.


Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[WolfHR]

I would assume that it means attached in such way that the wheel is unable to move in any way relative to the shaft (rotation, sliding, &c). I'm sure I've encountered phrase "positively located" on a number of occasions, and I'd venture a guess that this phrase was meant to be synonymous... On a side note, there is number of ways to e.g. attach the wheel to the shaft to transmit torque, but not that it is 'positively located' (for example, with spline which would, unless additional means of securing it from sliding, not be 'positively attached' to the wheel). Of course, I'm prepared to stand corrected since english is not my native language...

 

[rb1957]

Uncle Tom's lemma "words fail, see sketch" (though some sketches we see here are examples of the exception to the rule)

 

[mfgenggear]

I prefer pictures
1 drawing = one thousand words

positively attached = (assy) make sure it is not lose for dummies. lol

HTH

Mfgenggear

 

[IRstuff]

It used to be on older cars that the hub nut was kept in place with a hat that fitted over the nut with a slot for a cotter pin.

Otherwise, I would think lanyard for "positive attachment," but that wouldn't be appropriate for the described situation.

TTFN
faq731-376

 

[EngineerErrant]

Googling "positive attachment" net me this:

http://www.agi-seismic.com/code/ac184.html

In this sense, it basically means "resists a reasonable amount of force in any direction," which makes sense insofar as terminology is concerned. I'd imagine that, for your application, it just means that the wheel won't slide on the shaft once attached.

"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." -Scott Adams

 

[alfredoborba]

I would like to thank you all for the helpful answers. It is an expression that I have found in the API-611 regarding the kind of attachment that the toothed wheel for speed sensors shall have in the shaft. It make perfect sense for me now, after reading the answers. The wheel must not have any possibility of move relatively to the shaft!

 

[alfredoborba]

Thank some of you too for correcting my not so perfect english! It would be nice if you could understand my native language, but....;-)

 

[Artisi]

For me it means attached to the shaft by way of some mechanical means, ie, keyed with some form of locking nut or pin, scotchkeyed, threaded onto the shaft with secondary locking
system etc.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)