Electric Marble Lifter - Compatible to Gravitrax (R) V0.9

thingiverse

This is my first attempt at designing a marble lift. It utilizes a spiral drive mechanism to elevate marbles. The lift features two entries with corresponding exits and can simultaneously lift two marbles. With every rotation of the spiral, it picks up marbles. There's a short video demonstrating its basic functionality: https://youtu.be/G2JuTBZbeCU The spiral has a unique design, as its profile changes along the way up. At the bottom, the profile is concave to easily pick up marbles, while at the top, it's convex, causing the marble to fall out of the spiral. I designed the bottom surface angle (overhang) of the spiral to be 40° for smooth printing without support material. The lift is designed to utilize a Mabuchi 280 DC motor and two AA rechargeable batteries. It features a printed worm gear as transmission. In case the spiral drive becomes stuck, the worm gear is intended to swing back and avoid destruction. The motor holder can move on the gear base for normal operation. For normal operation, the motor holder is pulled against the gear base by a pull-spring. The worm gear is also my own design, with a printable upright in one piece without support material. I designed it with more easily printable angles first and then created the worm wheel to fit nicely. I've selected a Mabuchi RE-280SA-2865 motor (https://product.mabuchi-motor.com/detail.html?id=67). With two rechargeable NiMH batteries, it runs at approximately 5000 rpm without load. The worm gear ratio of 1:60 causes the spiral to turn about 1 to 1.4 turns per second. It takes six turns for the marble to reach the top. Therefore, the total lift time will be between six and eight point four seconds, which seems sufficient. I believe most motors with similar dimensions and data will function well. I've added a picture with the major motor dimensions for reference. The motor is secured into the motor holder using two zip ties, which are not shown in the pictures. I'll provide more assembly instructions and a bill-of-material later. UPDATE: 2019/06 Some people asked for a higher version of this marble lift. I designed one that's 72 mm taller. If your printer can print objects up to 208 mm high, you can print the body in one piece using gt_lift_body_high.stl and gt_lift_screw_high.stl. If your printer cannot print objects with a height of over 211 mm, you can use the versions with the split body and screw. Print the bottom and top parts separately, then glue them together with some Cyan Acrylate glue. Good luck!