Mechanical fuse?

I have a "X" axis table that moves through 3 linkages to follow a big cam.
There's a 7/8" dia. hard pin on the last linkage that actually moves the
table by pushing and pulling it back and forth. I have a steel block 3"
long x 1-1/2" wide x 1-1/2" thick that has a 7/8" bore on one end that fits
on the pin and a cam follower on the other end that pushes the table. The
block has two 3/8" set screws that locks it to the pin. If the table jams
due to a operator mistake or such, the hard pin will slip on the set screws
in the block. This prevents damage elsewhere. Irresistible force +
immovable object = $$$$. This happens a couple of time a month. I'm
worried that the set screws are going to tear-up the hard pin or the set
screws will be too tight or not tight enough.
Ideally, there exists something like a bearing or clutch that would be
locked-up until some force of say 100 ft-lbs. is applied then it would slip.
Anything like that on the shelf?
Reply to
Buerste
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Don't know how easily the usual ones fit into your design, but "torque limiter" will find a lot of products intended for this type of job.
Here's one (picked at random off the search results):
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Reply to
Ecnerwal
Look at 'ball plungers"
jsw
Reply to
Jim Wilkins
And if that is too fancy, there's always the Good Old Fashioned Shear Pin. KISS. Torque fuse. ;-P
Unfortunately it's not foolproof, if the fools have access to hardened bolts. But fools and expensive gear are soon parted.
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Reply to
Bruce L. Bergman
How about a brass plug or ball between the 3/8" setscrews and the hard pin? This is a traditional trick.
Joe Gwinn
Reply to
Joseph Gwinn
Recently I discovered that grade 2 field bolts have a real purpose. On a brush mower I was using they use it as a shear pin on the main PTO drive shaft wear it links to the gear box on the mower. Growing up I just couldn't comprehend why anybody even made grade 2 field bolts. LOL

Reply to
Bob La Londe
My brother used some bolts in my junk collection to fix grandpa's snowblower auger. He thought that a full diameter aluminum bolt would be safe compared to the steel undercut shear bolt that had failed when he sucked up something undigestable.
His mind was working but Ti is about 1/2 of steel but it is stronger than aluminum. He swallowed another undigestable item and broke a gear.
The Ti bolts were some pocket trash from working on Phantoms.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
Reply to
Wes

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