Replacement Gripper for Robie JR or Omnibot JR Robot

cults3d

Assembly video: https://youtu.be/mtYgDq9q3aQ This is a replacement gripper for the Radio Shack Robie Jr or Tomy Omni Jr. It will mount directly to an undamaged arm. Important: don't do the following unless the mount points on the toy are unusable. I bought a Robie Jr on Ebay that had the gripper mounts on both arms severely damaged. I have included a part called pivot that will replace the part of the arm the gripper mounts to. You have to cut off the pivot part of the arm and glue the new part on. It is important to observe the orientation of the pivot when you glue it on. The orientation is different for the left and right side. I used a solvent based glue called Scigrip 16 fast set. It seems to work pretty well on PLA. I'm not sure if the part can be removed without damaging the arm. If you need to remove it you might be able to drill it out. The pivot_X2 part is split for strength and printability. I glued it together with the same glue. I have included a bullet shaped tool you can use to help align the 2 parts for gluing. The design includes the stop that limits the rotation to 90 degrees. With the accuracy of 3D printed parts it was hard to get the gripper to stay in the place you rotate it to. I added some resistance to rotation by adding an optional O-ring between the gripper and arm. The O-ring is a 111/P11 from a Harbor Freight Oring kit.The OD is 15.6MM , ID is 10.8MM, section is 2.4MM. The grip_mount_btm part has 2 sacrificial bridges that have to be drilled out with a 3mm or 1/8 inch drill. Drill out the center hole of this part with the same drill so the 3mm screw will fit through it. Drill out the holes in the 2 gripper parts so they will rotate easily on the 3mm X 20MM screw. The 3MM X 20MM screw has to thread into the grip_mount_top part so don't drill it out. The gripper is designed in Fusion 360 and I will include the design files for you to modify if this doesn't fit your needs. The parts needed to assemble 1 gripper are: 2 springs from ball point pens 5mm dia. X 20MM 2 ea 3MM X 12MM button head screws 1 ea 3MM X 12MM button head screw optional O-ring from Harbor Freight kit I have included the Fusion 360 file for the design as well as the stl files. Good luck.