Chief Delphi - pic: 1675 Ultimate Protection Squad: Professor X

Quote:

Originally Posted by DampRobot (Post 1345840)

If you don't mind my asking, how does your linear punch work? What kind of linear bearings and release are you using? Spring force and travel? Shooting range?

I'm just curious about how someone else implemented a similar design, as we have a very similar robot.

We're using these linear bearings: http://www.mcmaster.com/#9338t1/=qreo4y
There are two of them spaced about 4" apart near the front of the arm. The plate they mount to is slotted sideways for adjustment to allow for proper alignment (we've actually been running the practice bot with both bearings loose so they are "floating" on the mount - there's quite a bit of play in the punch but its been working well). The shaft is an anodized aluminum shaft from McMaster.

We're still experimenting to find out sweet spot but right now we have about 14" of pullback. The back of the shaft has a tapped hole with an eyebolt with a nylon strap looped through. There is also a plate which the surgical tubing is attached to. The nylon strap goes back to a custom solid PVC drum on the Super Shifter. We modified the shifting block to allow for a larger diameter pneumatic cylinder to shift, but we're seeing some problems shifting to neutral with higher tensions. We're still experimenting there but we're finding that when there is too much friction to shift via the pneumatic alone, simply pulsing the motors to wind further relieves the friction enough to allow the dog to disengage. Its not 100% yet though and is top priority. Range right now I'd estimate our tension is only about 75 lbs and so our range is only about 10', but once its firing properly, that will increase substantially.