Suggestions Requested for Impact Test

[mewhg]

I am designing a machine and have a need to analyise how the mechanism inside is operating.

Specifically, there is a small spring loaded lever that is inside the machine. The lever is unlatched by another lever and the spring loaded lever moves under the power of the spring to strike another part.

I want to measure the time it takes the lever to strike the part from the time it becomes unlatched. This time varies from 1 ms to 20 ms.

I can't see or get to the part when the machine is together.....I want to mount something on the outside of the machine to tell when the part is unlatched and then when it strikes.

How would you approach this problem? I would welcome any and all comments.

Cheers,

 

[GregLocock]

accelerometers, or strain gauges or even microphones. You'd need one that is 'sensitive' to the unlatching and another that is sensitive to the impact. Or use LEDs and optical sensors to pick up themotion.

FWIW a decent mechanisms model could probably model it reasonably well, and would be easier to study.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[mewhg]

Greg,

Thanks for the reply. I was thinking too of accelerometers. Let's say I went this route....could anyone make specific equipment recommendations that might not break the bank?

Cheers,
Bill

 

[GregLocock]

You can hire the equipment for a less than eye watering price.

Guessing that your mechanism is pretty small, I'd suggest an Endevco 222C as it is the smallest accelerometer I know of, and it has good high frequency response. Against that it is not very sensitive. Bruel and Kjaer make some small accelerometers that are reasonably sensitive, but nothing as small as the 222







Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Maui]

Could you install a simple electrical circuit that would open when the lever is unlatched and close when the lever strikes the other part? This should allow you to accurately determine the elapsed time provided you have the necessary analytical equipment.

Maui

Constants aren't; variables won't.