oh.. I am sorry, I just checked your last post.
I thought the recent free up and down mechanism is the last thing that I have to modify. But it is not. I just encountered with more mechanical problems. At first, I attached one carrier with the recent up and down mechanism attached to it. when I test, the reading was perfect. But, when I attached 10 of the carrier attached with the mechanism, I could find the problem.
The chain leans side to side in an irregular pattern. On some certain chain link, it does not lean. but strangely, most of the chain link leans to side when the chain slides on the chain guide.
To cure it, I increased the height of chain guide recently. The chain guide is composed of still bars(12mm x 12mm x 300mm). This is used to sustain the alignment of the chain from one sprocket to the other sprocket. That leaning causes the free up and down mechanism to lean, as a result, causing friction in the joint of the mechanism because the joint stucks when the chain leans.
I realized that this happens because there is no mechanism for chain tension!!!
What a genius. I built a conveyor without a mechanism for chain tension adjustment. I was angry with me so much that I felt dizzy when I discovered this problem.
Anyway, that's why I tried to increase the height of chain guide.
So, I took everything apart from the conveyor except the structure itself in order to move the chain guide.
But, adjusting the height of chain guide is not enough. The space is limited. I pulled up the chain guide as much as I can.
but this also causes another error.
The two sprockets which are used to drive the chain is designed for the original height of the chain guide. So, if I increase the height of the chain guide, the carrier goes to the sprocket will be crushed because, the spinning range of the sprocket. When the chain guide is in the original height which was lower than the teeth of sprocket, carrier actually goes up a little bit without sliding on the rollers and spins with the sprocket.
But, now, I pulled up the height of the chain guide higher than the teeth of the sprocket, therefore, the carrier still in contact with the roller when it reached to the sprocket for the rotation.
I don't have camera with me right now, but this drawing will show it.
The sprocket is installed like this.http://www.flickr.com/photos/34955071@N02/4057559361/sizes/o/
So, due to that eage of the conveyor frame the carrier can not rotate with the sprocket while making contact with rollers.