Cylinder to tup connection

[don schad]

I was wondering what opinions people might have on the suitability of a ball-joint bearing for the cylinder-to-tup connection of a Kinyon (e.g., McMaster - Spherical Ball Joint)? This would seem like a very good connection for the top (assuming a suspended cylinder), but I am wondering about how these would fare given the impact they would be subjected to. Would the ball be pulverized in short order?


All opinions welcome.

Thanks,

don

[finn;-)]

I would have to suspect that it would wear out in short order. Since they tend to wear out on cars, and a air hammer would beat that joint up a lot worse than a car on potholes. Then there is the issue of what does a catastrophic failure look like in your hammer? versus the ball joint going bad on your car... things to consider;-)

[Nakedanvil - Grant Sarver]

I'm with finn, bad idea! Bad Dog, down, sit, good boy!

[firefarm39]

Don't the Iron Kiss hammers have something like a ball joint connection? You might try talking to John Larson and see what he uses.

[youngdylan]

Don't the Iron Kiss hammers have something like a ball joint connection? You might try talking to John Larson and see what he uses.

I know Norgren (and probably others) do a coupler that goes on the rod end that is meant to deal with any misalignment issues. I've had the odd thoght about trying one but kinda suspect it's a bit delicate.

Over a decade I've had 5, rods brake where they go down from 20mm to an M16 thread. There's quite sharp corners around this area so they will act act pretty good stress risers. I've thought about making a bespoke rod from EN24T (4340???) that doesn't neck down, ie an M20 thread with nicely radiused roots on an 20mm rod.

What I do on my "conventional" Kinyon is use a 400mm cylinder but only using the top 350mm of stoke. When the rod breaks I re cut the threads .... Norgren spares aren't cheap. I can get 3 "lifes" out of one rod. Next time it goes I'll cut an M20 thread.

Guess what I should really do is cut down on the cold work I do on it (insert usual excuses here)

[don schad]

Thanks for the comments.

There are alignment couplers which I have heard of people using, but I've also heard they do break. I don't know what part of them breaks (they are a bit more complicated then a spherical bearing setup would be), so the question was intended to see if a people had a feeling if a ball might be more rugged. The original Kinyon plans from ABANA show specs for one.

Regarding failure - I don't think catastrophic failure is actually much of an issue - worse case (where the bearing instantly turns to dust) the cylinder/tup would not disconnect, just become very loose, and still constrained by the guides. No flying hammer heads, just dust and no doubt some enhanced verbal expression. (The original idea basically amounts to inserting a spherical bearing into the hole in a pivot-mount on the top of the tup and clevis/pin on rod end. The impact on the bearing is in the "radial" direction, so if the bearing is gone there is just a very bad fit for the pin).

Another different thought was to have a thin layer of hard rubber between the tup-to-rod connection, so that out-of-line motion of between the tup/rod could get taken up there instead of stressing the threaded rod end. This would be pretty easy to implement, and I don't think this would have an impact (pun intended) on the force of the blow.

Thanks again,

don

[youngdylan]

Another different thought was to have a thin layer of hard rubber between the tup-to-rod connection, so that out-of-line motion of between the tup/rod could get taken up there instead of stressing the threaded rod end. This would be pretty easy to implement, and I don't think this would have an impact (pun intended) on the force of the blow.

Don

Could you do a quick sketch of what you've got in mind. You've piqued my curiousity with a rubber coupler.

I've also considered using a hydraulic cylinder (which have much thicker rods). Only problem is the thicker rods takes away from the area of air pressing up and it makes an already unblanced design a lot more unbalanced.

[Mainely,Bob]

Quick question that stems from my manufacturing background.Anybody ever thought about designing some flex into the cylinder mount?

The cylinder to tup connection seems to be the weak link as most air cylinders are not the most heavy design to come down the pike.I`ve seen them snap off at the thread using both internal and external thread on the rod end.Internal thread only means the link breaks instead of the rod end which is favorable if you can get the stub out and replace the link.

I had also thought about using hydraulic cylinders as they are way more HD in design and have better parts in areas like seals,rings and wipers to accomodate the higher pressures and stresses.There are also a lot more used hydraulic cylinders available here than there are pneumatics.

The reason I asked the question is that I now see Ron`s new design incorporates a leaf spring between the cylinder and the tup.I`m assuming he did this to ease the pounding on that weak link and maybe also to add a little of that "whip" that apparently make mechanicals harder hitting.Seems to me mechanicals use inertia to their advantage(shock absorbing springs and/or links that allow rather free movement of the tup) while pneumatics are constantly trying to overcome inertia by their ridgid mounting between the powering mechanism(the cylinder) and the tup.Rigid mounting+heavy pounding=breakage at weakest point.
I know the air cushion is supposed to act as a spring does and cushion the pounding yet the failure rate is still higher than mechanicals from what my limited research tells me.

When faced with a machine using an air cylinder that was consistently snapping the link or rod at the end of rod connection we found that changing the cylinder mount and allowing the cylinder to "float' alittle(thru a limited spring or rubber mounting) absorbed most of the shock and took alot of the stress off the connection and things lasted longer.
Would this be a valid approach here or am I missing something obvious?

[youngdylan]

The reason I asked the question is that I now see Ron`s new design incorporates a leaf spring between the cylinder and the tup.I`m assuming he did this to ease the pounding on that weak link and maybe also to add a little of that "whip" that apparently make mechanicals harder hitting.Seems to me mechanicals use inertia to their advantage(shock absorbing springs and/or links that allow rather free movement of the tup) while pneumatics are constantly trying to overcome inertia by their ridgid mounting between the powering mechanism(the cylinder) and the tup.Rigid mounting+heavy pounding=breakage at weakest point.
I know the air cushion is supposed to act as a spring does and cushion the pounding yet the failure rate is still higher than mechanicals from what my limited research tells me.

Bob

I'm not sure how inherent the rod breakage is with Kinyons ... I do tend to beast mine, eg using the natural texture of the flat dies to hammer a "micro texture" into cold 1mm copper sheet.

I only saw the new kinyon Design for the first time yesterday and I'm still getting a measure of it. Gut reaction is "I LIKE". It might be worth speaking to Harold to see if it's ok to put the picture of it on this thread so anyone that missed it in the other can see it. As mentioned, I like the pulling instead of pushing of the cylinder so its more balanced/controllable, The other thing that might appeal to me is the use of rubber bushing ???. I think I can see one on on end of the spring. He might be using them around the rod and tup connections. Kinda intruiged how they last and what the effect on the hammer dynamics are. Iguess I could be barking up the wrong tree with this rubber bushing thing but it'll be good to hear the Guru's thoughts .... GRANT/JOHN YOU'RE NEEDED OVER HERE

It's worth also pointing out to would be hammer builders how short and fat the airlines are and how big a valve he's using for a small (ish) cylinder. Yeah I know .... any excuse for me to bang on about this.

I'm not sure about "whip" you refer to with mechanicals cos I've never built or even used one (only seen 2 in the flesh)

I'd love to hears peoples thoughts on the new Kinyon ... fancy starting a new thread?

[don schad]

Could you do a quick sketch of what you've got in mind. You've piqued my curiousity with a rubber coupler.

Pretty simple, but a picture is worth 1000 words:



So the rubber is sandwiched between the rigid rod mount and main tup. The thinking was that if the dies hit some iron which is off-center and want to twist that twisting motion will be absorbed in the compression/expansion of the rubber, instead of the rod fighting it. Or at least that is the theory (not necessarily related to any particular reality).

don

[youngdylan]

So the rubber is sandwiched between the rigid rod mount and main tup. The thinking was that if the dies hit some iron which is off-center and want to twist that twisting motion will be absorbed in the compression/expansion of the rubber, instead of the rod fighting it. Or at least that is the theory (not necessarily related to any particular reality).

Dan

I'm not too up on vibration isolation but some of the shock waves would travel throght the connecting bolts, they could snap, but they could also transmit the shock waves through to the rod connection. To stop this, the bolts would probably have to be isolated from any direct metal contact with tup. I'm not sure of the effect on the hammer blow dynamics and how much punishment things could take. Resonant frequencies of mass spring systems are another thing to consider.

[Nakedanvil - Grant Sarver]

I think a good thing to experiment with would be a spring coupling virtually identical to the bottom rod connection of the KA75. Ya bore a deep hole in the top of the ram, drop in a very stiff spring then the rod would go in with a "lump" on the end (maybe double nuts) then another spring then a threaded bushing that screws into the ram and compresses the springs, or a bolt down flange like you see on some packing joints. Should be a nice connection.

Don's idea might work better with another piece of rubber and another plate on top of that, then the "rod-plate" would be sandwiched between two pieces of rubber.

I believe John Larson is using a custom ball-and-socket joint. Not to be confused with a spherical rod end or heim joint.

[youngdylan]

I think a good thing to experiment with would be a spring coupling virtually identical to the bottom rod connection of the KA75. Ya bore a deep hole in the top of the ram, drop in a very stiff spring then the rod would go in with a "lump" on the end (maybe double nuts) then another spring then a threaded bushing that screws into the ram and compresses the springs. Should be a nice connection.

I believe John Larson is using a custom ball-and-socket joint. Not to be confused with a spherical rod end or heim joint.

nice one Grant!

do you think there'll be any issue with resonances or should I take the advice I dish out to others .... suck it and see.

[Nakedanvil - Grant Sarver]

You don't want "sproingy©" springs, I'd use very stiff ones. We're just trying to absorb a little shock. 

[youngdylan]

I think a good thing to experiment with would be a spring coupling virtually identical to the bottom rod connection of the KA75. Ya bore a deep hole in the top of the ram, drop in a very stiff spring then the rod would go in with a "lump" on the end (maybe double nuts) then another spring then a threaded bushing that screws into the ram and compresses the springs, or a bolt down flange like you see on some packing joints. Should be a nice connection.

Don's idea might work better with another piece of rubber and another plate on top of that, then the "rod-plate" would be sandwiched between two pieces of rubber.

I believe John Larson is using a custom ball-and-socket joint. Not to be confused with a spherical rod end or heim joint.

Is this thing with the rods snapping an issue with air hammers such the Massey "slide" models (non Clearspace)
where the tup connects to the cylinder via a (beefy) rod. How is this connection made, is it rigid, does it just rely on a big f*** off diameter thread, why is the shape of a tortoise so steamlined?

[youngdylan]

You don't want "sproingy" springs, I'd use very stiff ones. We're just trying to absorb a little shock.

truck valve spring sized?

[Nakedanvil - Grant Sarver]

Something rated 200-300 lb/in.

[youngdylan]

Something rated 200-300 lb/in.

N/m on the civilized side of the pond

[Nakedanvil - Grant Sarver]

I don't know how they rate springs, I was talking about 200-300 pounds to compress the spring 1 inch. How ya gonna compress the spring 1 meter?????????

[youngdylan]

I don't know how they rate springs, I was talking about 200-300 pounds to compress the spring 1 inch. How ya gonna compress the spring 1 meter?????????

2m long spring?

failing that 4 kg/mm?

Grant did you see me question on the tup connection with "slide" air hammers ... very curious how thats done

[Nakedanvil - Grant Sarver]

I don't have any idea what you're talking about. Do you?

[Nakedanvil - Grant Sarver]

Don't call me "Guru", I much prefer S.T.O.C.K............Stuff The Old Coot Knows! Like: "Hey, we need some S.T.O.C.K. over here"! I'd call my website "The Stockyard"!

[youngdylan]

I don't have any idea what you're talking about. Do you?

Much more not than often

The tup/rod connection in this type hammer. Or is the rod/tup a one piece forging with a detachable connection to the piston. Or should I (insert appropriate response here)

[Nakedanvil - Grant Sarver]

Generally there is a tapered socket in the ram and a taper on the end of the rod.

[Bob S]

Bob
I only saw the new kinyon Design for the first time yesterday.................

I'd love to hears peoples thoughts on the new Kinyon ... fancy starting a new thread?

I'm all for a new thread discussing the 'new Kinyon'. Are there pictures?

Bob