Two adjustments for one thread 4

[LCform]

I have to reproduce a part, that at one end, it has externeal threads. While it is ribbed from sides, so a screw from inside, widens the diameter of this hole, but I see that also from outside, the ring that is going to be threaded on this shaft is also adjustable in tightness, my question is why there are two adjustable pieces used for this peice ? in the image you can see the piece

 

[byrdj]

So, IF the thumbscrew only distorts the outer threads BEFORE the clamp is tighten, why not machine the shaft with threads to suite and not add the unnecessary expense of drilling, taping, slotting and making the thumb screw?

 

[Artisi]

Seeing as how it's a guessing game, my guess is that it's a fine adjustment system for locating a component in a particular point in a process system. The outer thread and locking system is for a coarse adjustment and the inner the fine adjustment and all locked into position with the clamping arrangement of the outer locking ring once final adjustment is made.

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.)

 

[alloyboy]

This appears to be a hydraulic ram with an internal dampening adjusting rod for restricting the oil flow at the
end of the stroke. Probably from a shock absorber. IMO.

 

[Tmoose]

"the slot is only to let the threads of the shaft to expand obviously."

What do you suppose the purpose of expanding the shaft might be?

I'd measure the male thumbscrew threads and mating internal threads before assuming shaft expansion is the intent.
Previous comments about the screw being fully seated sort of raise doubts about shaft expansion.
Even well used, I'd expect some measurable indication of taper of one thread or the other if forced expansion was the intent.
And I would definitely ask the folks that use the machine how it is supposed to work, and how well the sample was working, in case the one they provided is worn to the point of no longer functioning.

 

[3DDave]

To expand the threads the inner item would have to have tapered threads, otherwise the bending of the outer segments would eliminate thread contact except at one thread. The ring would then bend the remaining portion, probably plastically.

It is more likely that the outer clamp is a locking mechanism as is used on some tierods / tie rod ends.

http://image.fourwheeler.com/f/4730...ilt-for-abuse+synergy-suspension-tie-rod-ends

I prefer these to jam nuts because they can be released without damaging the tie rod even if the nut/bolt have to be cut loose due to corrosion.

 

[zeusfaber]

Even as an electrical engineer with a good collection of pliers to hand, I don't believe that you could put enough torque onto the knurled head of that bolt to get any useful amount of expansion on a shaft with walls as thick as I think that photo shows.

Could it be that the "designer" copied this arrangement from something he'd seen elsewhere that needed two adjustable axial stops.

I could see the head of the thumbscrew (assuming the thumbscrew is parallel threaded) being an extend stop and the collar being a retract stop. Tightening the clamp bolt on the collar nips both the collar onto the shaft and the shaft onto the inner screw, so you get to lock both stops off with a single action.

A.

 

[1gibson]

If it drops the bolts, you turn the little thingy on the end until it doesn't drop them anymore. A machine like that is probably touchy, so anything you can easily adjust might make the difference. I'd bet a lot of the parts are weird.

 

[BUGGAR]

I have several similar items in my workshop. Whenever I find various threaded parts, before I store them, I screw them together so I know which parts have the same threads for future use.