simple motion control solution

[bernie_carlton]

Or a low cost motor coupled to a 180 degree spring wrap clutch.

 

[pmdavis300]

Do a google search for "brakemotor". It's your best and simplest answer.

Do not use an inverter drive. You will have to add braking resistors after buying the drive and then you have to program the drive. Way more complex than necessary.

If wearing out the brake disc on the motor is an issue, you might want to consider a DC injection brake. This is an inexpensive electronic device that connects to your starter and shoots DC into the motor when the starter opens. The DC makes the motor stop turning almost immediately without anything wearing out. Braking intensity and brake on time is adjustable.

ive seen dc injection on vfd's and thats what i wanted to do, but i didnt want to use a vfd just for that. so they make actual dc injectors just for that? ill do a search

 

[OkiePC]

I have seen a machine with an indexing gearbox. I don't recall the name or how it worked, just that it was purely mechanical, very accurate, and didn't have any clutch or brake discs, it was done with cams somehow. I think the motor ran constantly, and we applied an air signal to trigger each cycle...

Google helped me find this, but my internet is too slow out here to dig deeper...

http://www.camcoindex.com/ID_ROLL.HTM

 

[JeffKiper]

I have used the Camco indexer mounted to a table to make an indexer for a press applicaton. Nice unit ,expensive, rock solid. They have a lobe in hem that indicates they are inposition. They have some dwell so overrun is not an issue.
Brake motor and some a Solid state starter with a few prox switches and it is a done deal.

 

[Honga]

If you have compressed air available you could use a pneumatic cylinder. Top throw 180 degree bottom 0. This could be actuated by a solenoid valve, hooked up to a timing relay.

This solution would rely on you not caring about continuous direction of rotation, as it would obviously cycle in a (in a perfect equilibrium situation) random fasion.

 

[pmdavis300]

well that indexer would be nice but it looks expensive... i should mention that this machine will be for a 2 week run and never used again which is why im looking for something cheap. that brake motor is looking like a good idea though

 

[bernie_carlton]

The wrap spring clutch is dead simple. Continous motor in on one side, intermittent motion out on the other. One trigger of the solenoid and it makes one cycle, 1, 2 or 4 stops.

 

[JeffKiper]

Cool Bernie. I have never seen them as a seperate clutch.

 

[pmdavis300]

The wrap spring clutch is dead simple. Continous motor in on one side, intermittent motion out on the other. One trigger of the solenoid and it makes one cycle, 1, 2 or 4 stops.

will call them tommorow

 

[bernie_carlton]

I hope it works for you. It should from your description. Sometimes we tend to overlook older technology that just does a simple job well.

 

[SMOKE]

I think a 180* air actuator would work fine. Has an adjustable hard stop for repeatability. I have used them for almost exact positioning.

 

[kamenges]

Originally posted by pmdavis300:

will call them tommorow

Look very carefully at your sizing. I have seen too many of these laying in little pieces on the production floor to universally recommend them for index motions.

Keith

 

[shooter]

make it mechanical with a spring as safety.

 

[boswellw]

Pneumatic actuator. If necessary, two gears with a chain-drive belt for correct travel with a mechanical limit. We use stuff like this all the time. Simple and effective.