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Davey Vibrometer?

went to a swap meet today, and I picked up a thing called a "Davey Vibrometer" made the the Vibroscope Company - it says "made in USA", the calibration sticker says "do not use after July 6, 1981" - this definately looks much much older than that - if i had to guess, I'd say 1940s or older.

so, what is it (yes, I know what it is, keep reading)

The face is a ground glass, with calibration marks. there is a mirror inside that is fixed, a small 6V light bulb and a slit to form a bean that is directed through the instrument to a small mirror in the back. The mirror pivots laterally, reflecting the beam of light back to the ground glass. The mirror pivot is held in two bearings (needle type). The shaft is wrapped with a piece of thread. One end of the thread goes to a spring, the other end goes to a lever which is in a housing that protrudes from the back. Moving the lever rotates the shaft by pulling on the thread, and this moves the beam back and forth on the ground glass. The ground glass area is about 4 inches long, full scale deflection is about .004. After some flailing around with a sticky bearing, I got it all working. the case is brass painted in that black wrinkle paint that used to be so common.

Ok, so that is WHAT it is, the question is, on what were these things used, and how old is it really? It is Model 1-1000. If I try Google, this time Google is not my friend - vibrometry has acquired a new meaning and is done by lasers, and is used in search and rescue. This looks like the kind of thing that might be mounted against a huge bearing to warn of failure, but I just don't know.

any of you have a clue? Would a photo in the drop box help? if yes, I can post one.

Reply to
Bill Noble
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From Google Patent search:

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Reply to
guillemd

From Google Patent search:

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excellent - good work - I hadn't thought of a patent search - and amazingly , it is almost exactly as described. But, though the patent describes using it with flashing lights to uncover phase relationships, it still isn't clear who was buying these things and what they were being used for. But the October 1928 patent date does at least clarify when it was most likely built.

thank you so much.

Reply to
Bill Noble

Glad to help. My guess is that it might have been used to measure RPM and/or balance rotating machinery, but I haven't used one. Seems like it could be an interesting tool.

Reply to
guillemd

A few more bits of info can be gleaned via Google book search:

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None of the promising entries have more than a snippet view though...

Reply to
Leon Fisk

The text at the bottom of the patent page says"

Wheel Balancing Machine

Pete Stanaitis

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Bill Noble wrote:

Reply to
spaco

Hi Pete, I think that that is the title of Patent # 5831152 -- "Wheel Balancing Machine". Patent # 5831152 references one of Davey's patents (#

2004270) as prior art. Denis G.
Reply to
guillemd

One possible use would be in balancing a dynamo in a hydro electric generating plant, ie. a dam on a big river. The flashing phase lights could identify the armature winding that had more weight than the others. Or at least get close to the overweight point.

These things run for decades without stopping for service, so balance is very important. It also occurs to me they might also find an out of balance position in the impeller driving the dynamo.

An electrical engineer working for your local power company may be able to help with the story behind your unit.

Paul

Reply to
co_farmer

snip---------------------->

One possible use would be in balancing a dynamo in a hydro electric generating plant, ie. a dam on a big river. The flashing phase lights could identify the armature winding that had more weight than the others. Or at least get close to the overweight point.

These things run for decades without stopping for service, so balance is very important. It also occurs to me they might also find an out of balance position in the impeller driving the dynamo.

An electrical engineer working for your local power company may be able to help with the story behind your unit.

Paul

Well, I rejected the flashing light part because THIS unit had a T5 type (looks like a little bullet) 6V bulb - and unless the frequency was really low, even this little filament won't flash on and off very well due to thermal inertia. And I think that incadescent lighting is original because the nameplate says "6V" on it. In 1928, a xenon strobe was not unknown, but the more likely lamp would have been neon.

This thing was mixed in a huge load of surplus stuff that one regular seller brings to the swap meet - most of his surplus stuff is cell phone and communications related, this thing clearly has nothing to do with that. all in all, a great mystery so far....

Reply to
Bill Noble

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