Dual Mode Spring Motor Rolling Chassis

myminifactory

Despite its identical gear ratios and smaller drive wheels compared to my previous "rolling chassis" designs ("Spring Motor Rolling Chassis Version 2" is available at http://www.thingiverse.com/thing:2011107, and "PLA Spring Motor, Rolling Chassis" can be found here: http://www.thingiverse.com/thing:430050), the Dual Mode Spring Motor Rolling Chassis outperforms both thanks to its dual mode operation. The first mode is identical to the previous two rolling chassis designs, utilizing a PLA spring to power the chassis. The second mode is new and referred to as "true coast". Previous designs relied on the pawl releasing from the pawl gear to "coast", which was limited by friction. "True coast" employs a floating pinion gear (I published a demonstrator here: http://www.thingiverse.com/thing:2025927). Under spring power, the rear axle is connected to the spring motor via the floating pinion gear and spring motor torque. When the spring energy is depleted, the floating pinion is disconnected from the rear axle by the rear axle gear itself, allowing the rear axle to freely spin and the chassis to truly coast. A video of the prototype can be viewed here: https://www.youtube.com/watch?v=-DkAy472jlo. A comparison between the "Spring Motor Rolling Chassis Version 2" and the "Dual Mode Spring Motor Rolling Chassis" is available at this link: https://www.youtube.com/watch?v=PjmT369N0wM. The photos displayed show the actual prototype on the left, with the output of Fusion 360 without o-rings shown on the right. To assemble this design, you will need to purchase four AS 568 #213 o-rings (1 3/16" O.D., 15/16" I.D., 1/8" diameter) and eight AS 568 #223 o-rings (1 7/8" O.D., 1 5/8" I.D., 1/8" diameter), which can be found online or at plumbing supply stores. Designed in Fusion 360, this model was sliced using Cura 2.3.1 and printed in PLA on an Ultimaker 2+ Extended and an Ultimaker 3 Extended. Printing details: Sliced using Cura 2.3.1, printed in PLA on an Ultimaker 2+ Extended and an Ultimaker 3 Extended at .1mm vertical resolution. To print this model, you will need to print "Knob and Axle.stl", "Chassis Left.stl", "Chassis Right.stl" and "Spring.stl" with 100% infill. The remaining components should be printed with 50% infill. Two of each of "Wheel Front.stl" and "Wheel Rear.stl" need to be printed, along with one each of the remaining parts. Study "Assembly.stl" carefully, noting the locations and positions of the various components as you assemble the model. To assemble this design: 1. Press "Gear Axle Rear.stl" onto "Axle Rear.stl". 2. Press "Gear Idler Small.stl" onto "Axle Gear Idler Small.stl". 3. Slide "Knob and Axle.stl" into "Chassis Right.stl", then press "Spring.stl" and "Pawl.stl" onto "Knob and Axle.stl". 4. Slide "Gear Pawl.stl" onto "Knob and Axle.stl". 5. Slide "Gear Spur.stl" onto the axle on "Chassis Right.stl". 6. Place the idler assembly ("Gear Idler Small.stl" and "Axle Gear Idler Small.stl") and rear axle assembly ("Axle Rear.stl" and "Gear Axle Rear.stl") into position in "Chassis Right.stl". 7. Press "Chassis Left.stl" onto "Chassis Right.stl". 8. Place the o-rings on the wheels. 9. Press one each of "Wheel Rear.stl" onto each end "Axle Rear.stl". 10. Position "Axle Front.stl" into the chassis assembly, and press one each of "Wheel Front.stl" onto each end of "Axle Front.stl".