Author Topic: Interesting and non electronic  (Read 1384 times)

SeanB

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Interesting and non electronic
« on: March 20, 2017, 02:23:31 PM »
This is something at work I did a quick bicentennial service on recently, giving it a bit of a clean up, new oil on the pivots and generally a quick going over and a resetting of the zero, along with a check of calibration.



The measuring mechanics, all nice castings and such, all with adjustable pivot points for long life.



Closer view of the conversion from linear motion of the shaft to turning the dial, reads from 0-120kg.



Other side view.



The dashpot, there to damp out the pointer motion, so it does not overshoot. Was very low so refilled with mineral oil till full.



The link from the balance pan, that sits on a set of knife edges, and gives a tension on the shaft proportional to applied mass.



The manufacturers plate, showing that it was made in 1956, so it is now old enough to qualify for an old age pension, but this one still works well, no batteries required.

This is an old Avery Personal Weigher, which used to be a common thing at the pharmacies around the world, and it used to have a coin mechanism on it ( long removed, it now is free to use) where you deposited a coin, and this unlocked the mechanism, allowing you to get your weight. Done when a household scale was something very uncommon, and you also found them in doctor's rooms for use there.

 This one is still in calibration, and has a certificate as well with traceability to the standard kilogram. The lab though has only one person who can actually adjust it if it needs it, and the agents for Avery Berkel no longer have any people who know how any more, they all are long on pension.

Hey, I got to use my Instrument Technician training on something non electronic, and love this oldie, it has done sterling duty over the decades, and hope to keep it around for more. Only curse is the odd screws on it, 1/4in BSB, which is not exactly a common thread any more, hard to get hold of, and even worse the screws are almost all a security type, and require a pin driver to undo them. Nothing a pair of vice grips though could not handle, and if I have to do it more often I will simply remove them, retap the holes to 10/24 UNC ( I can get that no problem, and have the recoil set for it) or 1/4 BSW and use easier to get fasteners.  I really do not want to go to M5 though, it would be a little bad to do so.

« Last Edit: March 20, 2017, 02:47:14 PM by SeanB »