Lift cable
 

So our team is making a lift with a cable attached to a tough box mini to act as a winch system to raise the lift. I see many other teams have this design as well. How exactly are your teams attaching the cables to the motors? every way we try it isn't strong enough to lift anything or it is too hard to attach.

Re: Lift cable
 

Well if you have a spool, you can drill a hole through it (perpendicular to the output shaft of gearbox), and run the cable through it. Once through, get cable end crimps and get a nice and solid crimp on it. Done correctly, that should be all you need. I would counter sink a hole for crimped end to set flush in spool to allow smoother wrapping.
-Ronnie

Re: Lift cable
 

We used this spool for our winch last year. Entirely 3D printed, designed to fit on the hex shaft output from a Vex Pro Ball Shifter. It worked like a champ through 2 week 0, 2 regionals, champs, state fair, an off season, and countless demos. Never had an issue with it or needed it replaced!

Re: Lift cable
 

As the first two posters indicated, the best way is to pass the cable through a small hole that must rotate with the shaft. If you are planning to wrap the cable directly around the shaft, try adding a wheel hub, passing the cable through one of the bolt holes in the hub, and placing a crimp (or even a knot) behind the hole that's too big to pull through.

Re: Lift cable
 

There is always silver solder!

Re: Lift cable
 

I agree the best thing is to have a spool and not fasten the cable directly to the gearbox shaft. This is what we did last year. Ignore the rust and lack of cable management.

http://i.imgur.com/W2Z6lOb.jpg

Re: Lift cable
 

Also, put enough cable so that there is always a wrap around the shaft or spool core. As shown above (or as I described with a hub), you're requiring extra torque at startup, and putting more stress on the mount point than if you had a wrap or two of cable adding their friction to the tug.

Re: Lift cable
 

I hope that was a joke, or meant to be used in conjunction with another means of securing the cable.

Re: Lift cable
 

We drilled a hole in the side wall of our spool, then tied a simple knot around the spool circumference (like the first step in tying your shoes) and passed the end of the cable through the hole in the side wall of the spool. We then swage crimped the end of the cable.
https://plus.google.com/photos/10166...54062264587931

How to swage crimp https://www.youtube.com/watch?v=RfLY6mOBzJ0

Re: Lift cable
 

Thank you all for the great input!

Re: Lift cable
 

Silver solder is an amazing way of attaching to most types of cable(not plated) you can just silver solder on a nice neat little eyelet. Or any other fastening method you might wish to use, a bolt might be a great method as well.

Silver solder allows you to "weld" two same or dissimilar metals using a lot of heat. Like brass to stainless steel.

Re: Lift cable
 

Last year we had 2 nails running parallel to our winch shaft. Those two nails held the nylon strap down to the shaft, and they were zip-tied in place on the ends. It's the first time we ever put nails on a robot. It worked well for the short nylon strap, and I'd imagine it would work fine for non-metal cable, like parachute cord. I'll try to remember to snap a photo tonight.

Re: Lift cable
 

Small enough cable can also fit through set screw holes in a shaft collar. Though not sure how well it would work.

Re: Lift cable
 

FYI, "silver solder" is a term I have heard used interchangeably with "brazing".

Re: Lift cable
 

Every crane I've ever seen includes operating instructions to leave multiple turns of wire rope on the hoist drums...usually more than 3, sometimes as high as 9. This allows almost all of the force transfer to occur via friction and your mechanical connection doesn't see hardly any load.

We usually drill through the side of a drum and drill/tap a bolt and put an eye in the cable with a swege that goes around the bolt.

Another tip for spooling cable from the crane world is what we call "lagging". Basically, have your lathe team grind a radiused cutter that matches your cable and then turn the surface of your drum with a shallow spiral groove that matches how the cable would spool on it neatly. This helps it do so.

Good luck!