RASSOR - Contra-rotating, single arm configuration.

grabcad

This is my second entry for the RASSOR challenge.The configuration consists of two sets of contra-rotating drums with helical shaped single scoops.The simmetric configuration makes the reaction forces between the ground and the scoops to completely cancel each other out.This in turn makes it possible to use only one arm instead of two and proceed to the excavation more convetionally having one excavation front and a clean flat area behind it where RASSOR operates. To compensate for the halved volume bigger drums might be used.No internal baffles have been used, only a single long helical shaped scoop per drum has been installed to prevent (limit) backflow during loading.The total weight is less than 4 kg counting two drums and all the auxiliaries.Summary data:Total mass (2 drums + auxiliaries).............< 4 kgMaximum diameter.....................................450 mmMaximum length..........................................340 mm (170 mm x2)Maximum volume of regolith captured....32 (16x2) liters per pair of drums (theoretical, TBC experimentally)CONSTRUCTION:Most of the structures are made from 2 mm carbon fiber, scoops edges are made out of aluminum.A simple mechanism to invert the rotation of the adjacent drum can be examined in the drawings here provided.A couple of steel springs mounted at the end of each semi-axle pack the entire assembly and preload the rotation inversion device.All the sliding surfaces and surfaces subjects to wear are coated with water based anti friction coating.OPERATION:Regolite is loaded into the drums by applying torque to the L1 and R1 drums, these, in turn, transmit torque (opposite in sign) to L2 and R2 respectively through the relative rotation inversion mechanisms.During transport the drums must be kept positioned so to have the scoops facing upward to avoid spilling the content out.Unloading works as loading but with the torques inverted.Please have a look at the video, STEP model is provided as well as a printable pdf.