Mounting many rubber bands easily can be very difficult, especially if you’re using a lot of rubber bands. Zip ties will break themselves, or cut up the rubber bands, axles aren’t nearly strong enough, but standoffs and spacers are perfect for this. The standoffs provide the support, while the rubber band goes smoothly over the spacers.
It was taking way too long to try to get the rubber bands on, so one of our team members came up with this: (see attachment). The .75" standoff is attached to the shaft collar with a .875" screw, so that rubber bands can be looped over the standoff, brought over the spacers on the arm, and then brought back under and over the standoff. The standoff can then be angled differently, so that there’s less chance of rubber bands slipping off. The rubber bands never actually force the standoff to rotate, so there’s little chance of them falling off during a match. Just make sure to have a good amount of friction from the spacers pushing against the collar, so that it doesn’t twist while you’re attaching rubber bands. The nylon spacers on the sides are to keep the rubber bands from slipping onto the standoffs. You can reinforce the standoffs with other standoffs (two standoffs linked together are much more rigid than 1). Avoid having rubber bands slide over anything, as this introduces a lot of friction losses.
Also, it’s a good idea to make a sketch of your rubber band mounting (in a CAD program) so that you can get the force to be as constant as possible (although I’m still not sure how to get it perfect).
Ii found that the Pulleys in the Winch and Pulley Set are a much more viable, and Lightweight option. They only require 1 screw, and never fall off nor break(at least in my experience)
But of course this would require the Winch Set. If you don’t have that, I would strongly Recommend this.
Thanks For Sharing
We use standoffs as well, but we have to unscrew ours to replace rubber bands. It’s supported on both sides, so it can handle more force.
to make up for this though, we store 25 back up rubber bands attached from the usual mounting place to the drivetrain which doesn’t do anything. However, we can just pull a rubber band from the storage and loop it to our lift as needed.
The strength of the connection into the standoff may be a bit light for an obscene amount of rubber bands under significant tension. Not sure if a drop of lock tite would help or not.
Using the longest screw you can in a standoff holding the rubber bands helps prevent accidental and sometimes dangerous flying metal.
Looks like a great idea though!