Hi everyone, i want to build a claw arm that can turn 180 degrees. i saw some that use pneumatics. i tried using a pneumatic piston to turn a rack and pinion gear that turns a gear that turns the claw, but it doesn’t work 180
Look at my YouTube short that helps you understand how it works and what it does https://youtube.com/shorts/YV9-a5vscrU?feature=shared
My son’s team built one. It’s not a perfect 180 degrees, but it should be close enough for mix-and match. If using the large pneumatic cylinder, you can’t let it travel it’s full length if using the linear rack gear acting upon a 24-tooth gear.
In my video it shows how to 180 degree unit and you should have a stopper to get 180 degree
I did have my team watch your video and they enjoyed it. Our team watched a VEX video with a rotating claw and the attempted to reverse-engineer it, and came up with the following: It is close to 180 degree rotation, but not quite, as noted by the red-circled, green center shaft. They used a 0.5 pitch standoff, as that is what they figured out the VEX people likely used. It also helps hold the top plate (removed for photos) in place. They are figuring out how to attach it to their lift arm currently. Once done, we’ll try and get some pics out.
One thing I always ask our team members is when they build something, can they use fewer or smaller pieces to accomplish the same job. Sometimes the answer is yes, and sometimes no. They managed to reduce the mechanism above to a 4x8 backing plate with a 3x6 in the front. The claw is not attached, but they have the rotating piece built. They have used a few 3x6 plates in the robot so we busted open the Mobile Lab Hexbug kit because it has 5 of the dark orange 3x6 plates, as well as two small turntables and two astronaut figures (they stick those on the robot in various places sometimes).
Looks good and thanks for helping out today and we both learned with our teams thank you
Thank you this helps a lot