Tape tension circuit

[gcolbert]

At my work we have a Panasonic placement machine and Hover Davis electronic feeders. Some of the large feeders do not always pull the tape from the component reels. Consequently, the machine stops and an operator has to physically pull the tape tight or tie a heavy object on the tape using gravity to keep the tension tight for the next component to be placed.
I would like to design a circuit with a small motor that will roll the tape on a roller when tension is not detected. Strain gauge circuit?

Any advice would be greatly appreciated!

 

[RadioRon]

Hmmm, this is tough one, so naturally it is interesting. One application I saw recently simply chose to use a small motor with very low torque with no other controls other than a limited power supply. When the motor takes up the slack of the tape it just stalls and does nothing except keep the tension on. You would want to pick a very small motor and put a current limiter in line with it so that while it is stalling it doesn't overheat or anything. This sounds kind of crude though, so not my first choice, but it could be quite simple.

Personally I would find a mechanical solution using an additional spring tensioner of some sort to take up additional slack.

 

[Nigel Goodwin]

How about the tape recorder take up solution?, they use a low torque clutch to feed the take up spool, usually consisting of a felt washer against plastic, held together by a spring.

 

[gcolbert]

Thanks for your advise!

Now I have a couple of options to look into.

 

[zevon8]

I think you will find that a simple mechanical solution is far easier. If you do it electronically you will have to account for the changes in roll diameter, which will vary the speed and the torque to do the job. I like the clutch idea of Nigel's and on the same vein, how about an idler wheel on a fairly light spring? Almost like what used to be used on high speed transfer rollers or film projectors. Sort of a single pass accumulator, very common in industrial settings where machinery is fed from spools, right up to massive coils of steel sheet.