# Moving 4 items attached on shafts

1. Feb 27, 2012

I’m not sure if this is the right place to post, I hope it is. I’m a mechanical student and don’t have a lot of experience on how to move objects (yet). For a project I have to move 4 items which are attached on shafts. I would like to be able to move those items 180 degrees inside and back outside. Picture:

The items weight about 50kg each.

How should I do this with bearings?
How should I make those rotations? With 4 stepper motors or pinions or…?

2. Feb 27, 2012

### OldEngr63

You will surely need to provide bearing for the four shafts. The bearings have to both support the shafts and also allow them to turn.

As to how to cause the four rotations, that is a bit more indefinite. There are many ways, and you have not specified enough information. Will there be resistance to being turned? Must they all turn together? Is this to be a precision turn, or is the angle only approximate? How fast must the turn be made? Must the arms stop at the end of the turn, or do they continue to travel?

You could consider a single motor drive with a belt and four pulleys, for example, if that will give the performance that you need. You could devise a mechanism linking all four to turn together is that is required for precision. You could devise a gear drive. There are many possibilities, but you need to look at the rest of your requirements in order to choose.

3. Feb 28, 2012

The four items will be in position 1. They will have to be able to move 180 degrees to position 2 and wait. There will be a load on them, after that they will move back from position 2 to position 1 while their still is a load on the items. Picture:

4. Feb 28, 2012

### OldEngr63

Looks like you may have a kinematic interference problem to deal with also. You better check your dimensions to see if that is a problem or not. Your Fig 2 suggests that you cannot simply open out the flippers without the opposite ends engaging.

5. Mar 13, 2012

True, in this picture. But it's just a quick drawing I made to explain the situation.

Basically it's like this, to make it more clear:

Any tips guys?

Last edited: Mar 13, 2012
6. Mar 13, 2012

### OldEngr63

How to drive these flaps depends on a number of things that you have not identified as yet. What is the source of the load? What is the environment for the whole assembly? What are the capabilities of your shop?

You mentioned stepper motors as a possibility, and indeed they may be, depending on the amount of load that they have to work against. Other possibilities include a variety of motor driven gear systems, motor driven belt systems, etc.

7. Mar 14, 2012