On Fri, 27 May 2016 13:50:22 -0500, Jon Elson
wrote:

Ned Simmons wrote:


I'd be reluctant to call the folks who designed the machine idiots.
Normally, yes. But, if the only way to stop the pallet is by shutting off
an AC motor and letting the whole system coast to a stop, AND it is required
that the pallet index reliably, then I'm sorry, but this was a bad design.
Certainly, if no precision was needed, it would be fine. If precision
indexing was desired, then even in 1960, the technology was available.

It's a big leap from recognizing that the design isn't currently ideal
to claiming that someone's an idiot. Seems to me to conclude that
you'd have assume that the machine is being used as it was first
conceived; that there haven't been changes since it was built; and
that the OP's explanation of the machine is complete & correct. The
first two are very unlikely if the machine is indeed over 50 years
old. The OP has added some info in later posts that belies the third.


You could use a shot pin, as you say, or a hydraulic valve that would stop
the hydraulic motor much more rapidly than the coasting motor. Or, a Geneva
mechanism to advance the pallets and index them, and a small coast of the
hydraulic motor would not cause the pallet to move. So, there were lost of
WELL-KNOWN techniques that were in widespread use much more than 50 years
ago.

Jon

Later posts indicate there is a shot pin or similar device on the
table.

--
Ned Simmons