[Lester444]

Hello Folks.


Here's my attempt at this belt system. At the moment (Covid-19 days) GT2-6mm belts are all I have so it is what I used. I do know that GT2 does not mate to itself. Just hoping for a reasonable lifespan with what I have. I can live with slow feed rate, shallow DOC.


I will make a 5-ft length version for cutting plywood or plastics, single axis only for now. The green-colored cylinder is a small 700w router.

[spumco]

Hello Folks.


Here's my attempt at this belt system. At the moment (Covid-19 days) GT2-6mm belts are all I have so it is what I used. I do know that GT2 does not mate to itself. Just hoping for a reasonable lifespan with what I have. I can live with slow feed rate, shallow DOC.


I will make a 5-ft length version for cutting plywood or plastics, single axis only for now. The green-colored cylinder is a small 700w router.

Nice job.

If I could make an observation without (hopefully) sounding like an armchair critic...

Your configuration places the drive belt on the rack belt without the pre-loading that the basic Bell-Everman system achieves. The GT2 belts may - probably do - have less backlash when belt-to-belt than T5. But the way you have the idler/rollers configured they're just keeping the drive belt flat against the rack. Tons of engagment length - good - but any slop between the drive teeth and rack teeth is still there.

On the other hand, the centrally-located Bell-Everman pinion, when tensioned away from the rack belt, preloads the drive belt teeth against the opposite flanks of the rack belt teeth - in both directions. I think this is how B-E achieves such low backlash with otherwise sloppy T5 belts.

I'm not poo-pooing your machine. Run the heck out of it and if it works for you then that's a win. But if you find yourself chasing backlash or jerky direction changes you might have a re-think about the drive belt configuration.

[JustPlaneSweet]

spumco,

If you look at the fourth image you can see four rollers. The belt is pushed in between the two middle rollers and is looped around a sprocket on the servomotor. The servomotor is pulled tight which seats the drive belt against both sides of the fixed belt. No backlash. The drive belt portion that loops around the servomotor is always tight. The drive belt portion that loops around the back is always loose.

Stan

[spumco]

spumco,

If you look at the fourth image you can see four rollers. The belt is pushed in between the two middle rollers and is looped around a sprocket on the servomotor. The servomotor is pulled tight which seats the drive belt against both sides of the fixed belt. No backlash. The drive belt portion that loops around the servomotor is always tight. The drive belt portion that loops around the back is always loose.

Stan

Stan,

I was referring to post #361 when I offered some suggestions on belt configuration/path. I think the 'fourth image' you're referring to above is my drive system, which follows the basic B-E belt path.

-Ralph

[johntorr]

I am thinking of using this type of belt system for commercial use and wondering if this design is protected by patents, a quick google search shows that that the patents for this type of system has either expired or abandoned as this type of system has been in use since the 80s ( link )https://patents.google.com/patent/US5819584A/en https://patents.google.com/patent/US20090301237A1/en. I am not sure if there is something I am missing or if I would infringe on someones patents if I use this in a commercial application
Thanks
John