My team is currently building a telescoping lift using high-strength chain. My team has overcome boatloads of problems, but here we are, encountering more.
One issue is that when we tried to lift the arm, the chain broke. That only happened once, but a solution for the chain breaking would be helpful. Would trying to reduce the weight of the lift be good?
Our lift is leaning slightly to the side. Would adding some aluminum supports help?
Sometimes, the chain falls off the gears. Any idea how to keep the chain in place?
Thanks for all the advice, we’ll try your suggestions tomorrow. But what do you mean by doubling it up? And what is a sprocket? (Sorry, I’m new at this stuff.)
Thanks for all the advice, we’ll try your suggestions tomorrow. But what do you mean by doubling it up? And what is a sprocket? (Sorry, I’m new at this stuff.)
This is due to excess strain on the chain. So, to minimize this excess strain, you can either minimize your load, or minimize how much force is actually exerted by the chain. Minimizing your load will come from reducing the number of objects you pick up, and/or lowering the weight of the intake and lift. Typically, teams resort to aluminum or plastic, but creative use of smaller parts can achieve a similar effect. To reduce the force on each point of chain, you can add rubber bands or simply put more chain side by side as suggested before.
Aluminum supports will help to an extent. If you’re using only a single linear slide what you could be experience is the resulting imprecision of a single part. Though vex fabricates their parts well, there is still some wiggle room for things to occur as things are scaled up. To fix this, you’ll need to double up the linear slides and spread out the actual system. Mainly, if you you want to reinforce the stages with aluminum supports, attach them to the base of the robot because any backlash there will multiply quickly.
This is almost always because the gears aren’t aligned. Use spacers on the axles to get the precise position you need. If that still doesn’t help, you can use gears, plastic cut outs, or strips of metal as rails
Stringing rubber bands from the bottom of the 2nd stage to the top of the 1st stage will assist the lifting of the elevator and cancel out some of the weight of the lift.
Adding more motors to the lift is always useful if you’ve got extra motors (within your limit of 10) that have no other use. How many are you using currently?
As mentioned before, you can string it to previous stages.
Adding another motor will not help you with your chain snapping problem, for the chain still experiences the same, if not more strain due to faster acceleration of motors. Adding elastic however will reduce the the strain on the chain.
Our team built a 6 foot elevator lift this year for Skyrise, and I can tell you, it takes a lot of maintenance and fine-tuning to get the lift to work well. Some tips based on experience:
-Use at least 2 loops of chain–it breaks very easily if too much chain is put on it
-Make sure the chain is tight, not too tight but tight enough so the taking one chain off will make it unable to be connected
-Use lots and lots of grease, I recommend lithium grease (from a tube, aerosol is illegal)
-Lots and lots of rubberbands; unfortunately these only help to a certain extent, we didn’t have enough time to but dontworryaboutit has a nice design here
-If you are going more than 2 or 3 stages, use the old linear slides and not the new ones; it seems the new ones wear out easily and have a lot of wiggle room; even two of them doesn’t help that much, we had 5 stages and the top stage could move 3-4 inches side to side because of the wiggling
-Make the slides face opposite each other, I don’t remember where I saw it but there was a post a little while ago about not having two outer members on one stage and two inner members on the next
-Make sure the slides are parallel or they will have a bunch of friction
-If it’s not obvious enough, use aluminum
-Aluminum can reduce weight; however, you also need to reduce weight on the intake and have enough room to lift at least 2 pounds
That seems to be it! Make sure you have enough time to test it out-it took my team more than two weeks to work out half of the kinks. Good luck!
Are the motors on the part that moves up and down? Why would you put that weight on the part you need to lift? Is there something about managing the chain that helps with it placed there?
To double up the chain, could I just have 2 sprockets on 1 shaft and have 2 separate rows of chain? And do you know if aluminum linear slides exist anywhere?
And where do you apply grease?
GSPS
2 sprockets on 1 shaft works, or you can have 2 separate rows of chain, your choice! My team had two separate rows of chain because that’s what the design accommodated.
There are, unfortunately, no aluminum slides
And just apply grease between the slides, where the metal rubs against itself. Basically wherever there’s metal to metal contact you’ll want to apply some. It’s also a good idea to manually slide the lift up and down a lot before you attach it to the motors to get it as evenly spread as possible.
This also holds true if you end up using the new linear slides. The only differences are the size of the slides, the amount of overlap, and the material that the slides are made of.
Yes, definitely! The thing is I wouldn’t recommend using the new slides. They are lighter but they are really wobbly and the trucks don’t always fit that well into the rails… Like I said earlier, our lift could wiggle side to side more than 4 inches
The thing is I wouldn’t recommend using the new slides. They are lighter but they are really wobbly and the trucks don’t always fit that well into the rails… Like I said earlier, our lift could wiggle side to side more than 4 inches