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hardinge vari-grip closer

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Weldingrod1

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#1
Well, I scored one on eBay... I have a parts list and cross section, and only a couple of missing parts. Does anyone out there have one? I am having a hard time understanding what the little pistons are supposed to do. They seem to do some sort of venting function, but I can't see why they are there! Are the air passages so small that it cycles super slowly?
Thanks,
WeldingRod
 

Weldingrod1

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I looked at the drawing and thought about it a LOT more (sligthly hampered by by flu-addled brain)... It turns out that the little cylinder and poppets are pilot operated check valve. When you pressurize the open port, the close side of the cylinder is opened to the close air port by one little cylinder pushing open its check valve; this lets the close air out. The open air side flows past its check valve until the open side is at full air pressure. Once the air flow stops, the open side check valve closes. The key thing is that the air is TRAPPED in the air cylinder! You can turn off the air supply completely after this! So, it doesn't really matter that the Hardinge swivel thing leaks like crazy; you don't need to keep it presurized.
 
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