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# Synchronizing Shafts in Parallel

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## Synchronizing Shafts in Parallel

(OP)
I need to synchronize 6 parallel shafts to rotate 180 degrees forward and backward at 10x/min. The load is very low <2 lbs. I'm finding that gears are too expensive (I don't want to press fit). Pulleys connecting each shaft to the next would work but maybe there is a better way. Can this be done with a linkage? Open to any ideas.

Thanks

### RE: Synchronizing Shafts in Parallel

Why are you assuming you have to press fit? Most gears are made to fit certain size shafts. You might need a keyway, or flats for set screws. Also, you can use a single roller chain driving sprockets on all the shafts. Individual shaft-to-shaft drive loops are not recommended because of accumulative free play.

### RE: Synchronizing Shafts in Parallel

(OP)
Not sure how to reply directly to a post...

@jlnsol I forgot to mention that the shafts are both parallel and laterally aligned in a row. (See attached) I think there would be a dead spot if j tried to use linkages to turn 180 degree forward and reverse.

@jboggs The majority of sprockets I have found with a set screw/keyway are ridiculously expensive. Maybe you can recommend me a vendor? I'm looking at ADP/si and McMaster. I thought about using a single roller chain but Im worried about the chain skipping because of how the shafts are aligned. There wouldn't be much degree of contact on the sprockets. (See attached)

### RE: Synchronizing Shafts in Parallel

what about the system used for train locomotor ?

### RE: Synchronizing Shafts in Parallel

what do you mean "parallel and laterally aligned" ?

a linkage would work, to get around the "deadspot" have standoffs so the linkage would move up (and then down) as the shafts rotate; yes? (clear as mud ??) the motion would be from East thru North to West (if that makes any sense !?)

A single chain would work too, use a guard to ensure the chain doesn't jump (and to protect fingers and clothing).

another day in paradise, or is paradise one day closer ?

### RE: Synchronizing Shafts in Parallel

(OP)
@rb1957 The linkage that jlnsol posted had a different shaft configuration from what I am designing. Im probably not describing it correctly but see the photo I attached in my last post. By standoffs do you mean like an dead stop at east and west?

### RE: Synchronizing Shafts in Parallel

your pic looked like parallel shafts, linked by multiple chains; don't get the "laterally aligned" (didn't open the other pic)

your 180deg could be North to South, should would be harder to make a linkage (bent arms). if your 180deg is East thru North to West then simple stand-offs (linkages) will work.

I like the single chain idea.

another day in paradise, or is paradise one day closer ?

### RE: Synchronizing Shafts in Parallel

Please use the Upload Image feature to insert images.

### RE: Synchronizing Shafts in Parallel

Perhaps you should quantify what "ridiculously expensive" means to you.

It seems like your application does not require very precise synchronization. Some slippage would be tolerable?

Flat belts.
V belts.
Round belts.
Multi-rib belts.

If you really need "locked" sync, timing belt.

Span the whole thing with a conveyor belt and just drive one roller.

Tons of info and inspiration available from suppliers. For example:
http://www.durabelt.com/index.php
https://www.megadyneamericas.com/endless?_vsrefdom...
https://us.misumi-ec.com/vona2/mech/M1000000000/
https://www.gamut.com/c/power-transmission/pulleys...

### RE: Synchronizing Shafts in Parallel

The OP did insert a picture.

### RE: Synchronizing Shafts in Parallel

The OP "attached" a file that happened to be a picture.

The Upload Image function inserts an image directly into a post.

Lots of people don't want to, or are prohibited from downloading random files from the internet.

Inserting an image directly is far more helpful to the people who are trying to help understand and answer the question.

### RE: Synchronizing Shafts in Parallel

(OP)
@rb1957 I think I understand now. Thanks for your input. I think a single chain will be the best option. I'm wondering if tensioners between each of the shafts are necessary or if just a tensioning on the drive will be sufficient.

@MintJulep The gears I was finding were ~$100-200 a piece. 6 gears + idlers would add up to alot. The image I attached was just an example of the shaft orientation. I am rotating pneumatic grippers (pick, invert, place) at the end of the shafts so there can't be any slippage. ### RE: Synchronizing Shafts in Parallel More skinflint engineering. Spend the dang money. ### RE: Synchronizing Shafts in Parallel Then you must be looking at the gold-plated, sodium-filled titanium gears. Timing belt pulley in the size that I guess that you need should cost no more than$20. Probably closer to $10 ### RE: Synchronizing Shafts in Parallel What Mint said. Also, nylon gears, if they would be suitable for the application, are often less than$10 each.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

### RE: Synchronizing Shafts in Parallel

1> If you don't really need 180 degrees, solid linkages should work just fine up to 120 or 135 degrees.
2> You can use a single chain or belt in contact with all the pulleys - if you place a hold-down idler in between every other shaft. that insures some minimum wrap angle on each one.
3> Depending on the sizes and loads involved, you might check this source: www.andymark.com. Their parts are designed (and priced!) for educational robotics teams. They work great for their intended purpose. (They're heavy duty enough to enable a 120 lb robot to quickly and repeatedly lift itself off the ground with a onboard winch designed and built by high school students.)

### RE: Synchronizing Shafts in Parallel

Mint - Ok, but I find inline pictures to be a problem because they often are scaled down to illegibility. I suppose they could do both.

### RE: Synchronizing Shafts in Parallel

(OP)
@MintJulep I was talking about gears w/ keyway & setscrew, not timing pulleys, sorry for the confusion.

@Jboggs Unfortunately I need 180º travel. I decided to go with option #2 since the load is very low. That website looks great! I see things I can use for other projects.

Thanks all!

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