Kress ATC

[m_c]

I won't be building any soon. Got far too many other things to do, but a few doodles would indicate all the bits would fit in, however it would need a good few calculations to see what kind of forces would be involved and if they're acheivable.

Thinking outside the box a bit, use a set of ball bearings that go under a pull stud, that are then forced into place by a spring loaded outer tapered sleeve. The spring could even be assisted in locking by air pressure, as once the tapered sleeve is pulled up, using appropriate tapers it's essentially self locking.
Now for release, you have another set of bearings on top, that also run against a taper, but this taper when moved to release, forces the bearings between the top of the pullstud and another taper above the pull stud.
It would be quite a complex setup, needing hardening and grinding of various parts, and that's once you've figured out how to machine all the various bits to ensure the balls don't just drop out.

[Jonathan]

This discussion is getting dangerously close to this design:

Rapid Changer

I made a prototype of that just to test the mechanism, but a bit bigger. It holds the holder reasonably well, but since it was only a test I used a random grade of steel which didn't harden much and I didn't grind it. I think it could work, but I doubt the holding force and torque transmission would be that great.



I bought some EN19 steel to have a go at making a proper one...

[Ricardoco]

This discussion is getting dangerously close to this design:

Rapid Changer

I made a prototype of that just to test the mechanism, but a bit bigger. It holds the holder reasonably well, but since it was only a test I used a random grade of steel which didn't harden much and I didn't grind it. I think it could work, but I doubt the holding force and torque transmission would be that great.



I bought some EN19 steel to have a go at making a proper one...

Hey Jonathan, How did you heat the items up for hardening? I only ask since I did some hardening with a blow torch and it was OK but i did some in the furnace and OMG what a difference, as much in common as sun and rain.

[Jonathan]

Hey Jonathan, How did you heat the items up for hardening? I only ask since I did some hardening with a blow torch and it was OK but i did some in the furnace and OMG what a difference, as much in common as sun and rain.

Chucked them in the chimney if I recall correctly!

[Ricardoco]

Chucked them in the chimney if I recall correctly!

next time
, give it a try in a furnace of some description, and dont forget, bright red first time and blue the next and im sure you will be very pleased with the results..

Rick

[Jonathan]

next time
, give it a try in a furnace of some description, and dont forget, bright red first time and blue the next and im sure you will be very pleased with the results..

Rick

I've done it before and been pleased with the results - I think this was just a funny grade of steel. The fire was plenty hot enough to get the pieces bright red.