Timing belt elevators
 

Hello,
we were considering using a timing belt elevator this year in place of chain.
I know about timing belt spacing and tensioning, etc. but what I was wondering is how teams clamp their carriage to the belt itself. Does one simply clamp a plate over it, or is something more complex better? I can't find any examples online. A simple picture would be enough.
Also, if we go with 5mm HTD x 15mm wide pulleys, can we use two 18t pulleys or should we move to 24t due to the torque? we plan on 6 totes plus bin. I feel like the 15mm belt will make the 18t pulleys okay, but I'm not sure.
Thanks!

Re: Timing belt elevators
 

http://www.polybelt.com/clamingp.php

Google timing belt clamping plates.

We plan to use a long timing belt length, clamping each end to the carriage, adjusting clamp location and belt length for coarse belt tension, and possibly an idler for fine adjustments, as needed.

Re: Timing belt elevators
 

Jim,

Have you actually used/seen the clamps for HTD belt from polybelt? I see the picture they show on the item details page for HTD clamps doesn't have the round tooth profile. I didn't know if their pic just wasn't representative OR if they consider clamping round-tooth belts with a squareish-tooth clamp to be OK.

Thanks though for the link. This place is about 4x cheaper that anything we found just yesterday for these.

Re: Timing belt elevators
 

Thank you! I was wondering if there was something like that.

Re: Timing belt elevators
 

Re: Timing belt elevators
 

I'm worried about shipping from SDP-SI mainly. That is my first worry.
If it takes less than a week it will be fine, but more than and we're cutting it close.

Re: Timing belt elevators
 

We bought four clamps ourselves. As we are using 25 mm belt (~1"), we got 50 mm wide clamps. I'm pretty sure these were round profile; I'll check for sure on Tuesday (school closed this w/e) and report back.

Re: Timing belt elevators
 

Has anyone successfully 3D printed a timing belt clamp? I was thinking about trying that out.

Re: Timing belt elevators
 

We actually just purchased some of the same end clamps from polybelt. It seems to fit the 5mm HTD belts from gates and other suppliers many teams in FRC are used to. Here is what the profile of the clamp looks like.
Attachment 17891Attachment 17892

Re: Timing belt elevators
 

Way back in 2005, 1293 made an aluminum plate to clamp on the back, then another one on top that had cutouts in the shape of the tooth profile we used back then (don't ask me what it was--it was ten years ago!). You can't really see it here, but it's there. The lift worked fine all season.

Re: Timing belt elevators
 

We have made our own clamps in the past out of Al plate and a file. It doesn't take as long as you think and the results are perfectly fine.

Re: Timing belt elevators
 

That sounds quite good then. We'll be sure to order the parts then (or I can get some rookies to make them).
Thank you so much!

EDIT: What is the best way to tension the belt? Slots? If we order belts from sdp-si, how long is the shipping?

Re: Timing belt elevators
 

Yes, we did (for chain)! Here's a video of our engineering model:
https://www.youtube.com/watch?v=idJFSad9gCA

Re: Timing belt elevators
 

Speaking of timing belts, just thought that I would leave this here...

https://www.youtube.com/watch?v=TQY3FD4p6cA

Re: Timing belt elevators
 

That is literally the smoothest robot I've ever seen, uber-teams included. It's just so smooth in everything it does... I feel like you would have made a fantastic inbounder on Einstein even.

Re: Timing belt elevators
 

(maybe this is a general question but)

How do you attach the carriage to a chain loop?

Re: Timing belt elevators
 

A lot people have used screws, I know.

Re: Timing belt elevators
 

We printed a couple this weekend. We haven't properly tested them yet, but they seem like they'll work.

Re: Timing belt elevators
 

I made a couple of timing belt clamps in 2011 for Logomotion when we used a length Gates belt to drive the upper stage of a compound elevator. 10-15 minutes work with a hacksaw and files. It worked perfectly. Use a square to transfer the spacing from a belt to a piece of flat aluminum. Cut slots to depth with a hack saw. Clean up with a small 3 square file and/or needle files. An advantage over the purchase version referred to above was that the clamp plate had bolt holes to the sides so they didn't interfere with or damage the belt.

Re: Timing belt elevators
 

We are using M3 screws through holes in the #25 chain links. The other option I considered was using chain half-links, but figured maintenance would be easier and the build would generally be more reliable with closed loop chain

Re: Timing belt elevators
 

These are useful.
ANSI Roller Chain Attachment Links

EDIT: 250th Post!

Re: Timing belt elevators
 

What timing belts are you guys using, and where are you ordering them from?

We are having difficulty finding stock 12' timing belts

Re: Timing belt elevators
 

The longest I know of is 250T which is 250 teeth at 5mm per is 1250mm or 49" (just over 4ft). If you cut the belt and use the single sided mounting you could go nearly 4', but not 12' (or 6'). If you really need that travel, it may be simplest to switch to chain.

Re: Timing belt elevators
 

We got 30' of 25 mm wide belt from polybelt.com. We will cut to length. A bit pricey, sure.

Re: Timing belt elevators
 

For round tooth profiles plates can get slotted with a ball end mill very easily to make clamps.

Re: Timing belt elevators
 

You can also buy HTD belt or GT2 belt by the meter from SDP-SI

Re: Timing belt elevators
 

My team ordered some 3800 millimeter (about 12.45 feet) long, 15 mm wide belts from Motion Industries.

You can check them out here if you're interested.

Re: Timing belt elevators
 

Here is a test of our 3d printed belt clamp. It was printed on a Cube printer with PLA.



The plan is to have the printed piece epoxied to the aluminum plate on the bottom and the top plate will do the clamping.