Advice on replacing conveyor chain

[AppleExpress]

so, over the past 3 weeks i have been running into a serious problem that is only getting worse day by day. i am having rollers jam at the entry up. typically, being i am front wheel pull, my timing is set up to load 2 rollers up for the front wheel, then skip a roller, then load 2 more for the rear wheel. what's happening is the roller that is suppose to be skipped is slightly coming up then twisting to the right and jamming into the track. I then have to back the vehicle out over the first 2 rollers and use a crowbar to pull the chain back into place and reset the third roller. this is now happening anywhere from 2-10 times a day.

I am using a log chain currently, and have been told its not the ideal chain for this conveyor. So any thoughts on the SC78 chains? anyone running them, or having issues with them?

i have had 3 different companies in to look at the system and they are all telling me to replace the chain...it was just replaced in march. Adjustment looks good, tension is good, and the chain doesnt look twisted anywhere. ive also tried adjusting the timing so i only have 1 roller up in the front but then the second roller will jam. this isnt happening when the rear rollers come up, only the fronts. its very odd to me.

 

[JeffM]

A couple questions:

That type of conveyor are you running?
Have you checked to ensure that the roller up mechanism is bringing up both sides to the same height? Are any parts worn down?
How does the first 5 ft of your conveyor top look after the roller up door? Is it twisted?

Any problems with roller jams I have had are usually attributed to something in the roller up mechanism not lifting the roller to the right height. Why it is only happening on the 2nd roller, I'm not too sure, you will need to investigate more.

It is important to also check the conveyor deck after you have solved the problem; if the jammed roller has pulled the conveyor top down on one side you will need to try and correct it so that the rollers are coming out on a somewhat level surface.

I am running a Flapan conveyor with a SC-78 chain and have replaced the drum with a sprocket. Since we have switched to the rear sprocket several years ago we have not had problems with roller jams due to the chain slipping to one side. I also inspect the roller up mechanism monthly to ensure the rillers are being lifted out high enough so that nothing is catching.

With proper maintenance, you should be able to get 3-4 years out of a SC-78 chain. We flip ours every 200K cars or so and tighten/replace the roller bolts every 6 months.

Hope this helps.

 

[DavidM]

I would probably be slow to replace chain if it was already replaced this year. I assume you are using Sonny's equipment, have you spoken with them directly?

If you considering switching to a completely different kind of chain, I would look at x458 if it can be used on your conveyor.

David

 

[AppleExpress]

I am actually getting quotes on both the sc-78 and the x458. Price will determine which the company allows me to get. As far as conveyor type, i am using a sonny's convsc78...so it should have the sc-78 chain. it loos like the rollers are coming up to proper height. i think the problem actually lies in the conveyor itself. it looks like from wear, the very front edge of the conveyor, right where the door lays is very slightly bent down. i notice that the rollers when down slightly bump the edge and you can see the door raise about a 1/16 of an inch, but the rollers continue to stay under the conveyor as they should. My best guess at this time, is that because of that slight bend in the front edges combined with the tension on the chain from the 2 rollers being up, one side of the 3rd roller is coming up while the other goes down. but it doesnt explain to me why the rear wheel set never jams, only the front wheel set. i am using a drum up front and a sproket in the rear currently, both were replaced with the new chain in march.

 

[JeffM]

I would see if you can bend that part back up to resolve the clearance issue. Guaranteed that part that is bent down on the one side is the source of your problems. Seeing how you are front wheel pull I would suspect there will be more of a load on the 2nd roller then the rear two. If your chain is tracking to the inside with a load on it, the 2nd roller could come up to the inside and snag. More than likely the chain is back closer to center by the time the final 2 rollers come up.

You could also try Rotating/replacing your drum or switching to a rear idle sprocket to correct the side to side movement.

 

[AppleExpress]

ok, i will look into that, thanks for the advice jeff.

 

[JMMUSTANG]

Seems to me if it always happens to the first roller and not the second the air pressure to the fork might need adjusting.
Maybe the fork is not coming up quick enough for the first roller.
Since you put the new chain on in March have you tighten up your chain by removing some links?

 

[Washmee]

It's possible your chain tension is to high. It's so tight, that by having 2 rollers up the third roller is being pulled upward also and then it catches. Is that right? The reason the rear safety rollers don't cause the same effect is because there is no tension on them since they are not actually pushing on a tire.

my timing is set up to load 2 rollers up for the front wheel, then skip a roller, then load 2 more for the rear wheel. what's happening is the roller that is suppose to be skipped is slightly coming up then twisting to the right and jamming into the track.

I know it seems counter intuitive, but to have the chain run a little looser is better for the life of the chain.

 

[Earl Weiss]

If I understand this the third roller that is not supposed to come up comes up slightly and jams?

Ths sounds to me like the lift out is not dropping like it should.

I do not have a Sonny's unit so I am not sure if you have the lift outs simply drop with the weight of the roller when air is released or a 3 way solenoid that moves the lift out in each direction, one way to deliver a roller and the other to cancel?

If it is a release and drop by weight than if something is sticking, (Cylinder / hinge / bearing) then the weigh does not drop it fast enough. It could be the same or a solenoid valve that is not acting right in the cancel direction.

Also, check the top deck slot. It widens slighhtly where the rolers come up. Over time it wears and widens. If it is narrow enough the rollers can't get stuck. If it is worn it needs to be narrowed as much as possible. (Ditto on each side of the top deck no longer being level.

Finaly, worn rollers, worn wear they attach to the chain can cause this.

 

[AppleExpress]

My system uses the weight of the lift to drop when the air is cut. Ive watched the timing numerous times and the lift drops consistenly about a foot before the next roller reaches it, so i know that isnt the issue. I readjusted my timing on friday slightly to reduce the number of rollers coming up. i also found one roller that had a relatively loose roller, so i tightened that up and so far so good. ive only had 2 jams since friday....alot better than 8-10 a day i think.