Chevron Drum

Last crawled date: 1 year, 11 months ago

My Drum design extends to the full allowable dimensions, 450 mm diameter and 360 mm
width. A 1:4 model (tested with builders sand) has consistently filled to 58%, whilst a full
size drum could take that to >60%.
The chevron ‘tread’ and slight taper of the drum, directs loose material to the edges of the
drum, where (6) scoops each end (alternately) ingest an amount of the material, filling the
scoop cavity.
As the drum rotates, the scoop cavity contents are lifted, where the additional weight of the
contents open an inner flap, allowing the material to fall into the drum interior from a high
position in the drum. Drum contents (lower down) keep other flaps closed/sealed and
prevent contents falling out. As the drum fills, it reaches a point where the flaps are
prevented from opening (its maximum fill). This point is determined by the rill angle of the
material, and/or its tendency to clump/stick together. This point can be extended by
vibration of the drum, or a pulsed drive.
To empty the contents, the home-base processing facility will require an ‘unloading station’ the device drives into (not just a hole in the ground) containing a mechanism to push at the end of the
drums. When the drum end is pressed and released, the drum splits apart at the middle, allowing the contents to quickly spill out (assisted by the taper). When empty, press again to bring the two drum halves back together and lock closed.
The mobile device’ prime function is to travel to site, load material and return to home-base.
The unloading station should handle its function. Preferable to incorporate a method
for unloading into the stationery home-base facility than add complexity/weight to the
mobile device.
The drum to be constructed of Titanium by 3D printing a combined scoop end and inner
drum half (as one), with the other half being a mirror of that. The flaps would be of a
flexible elastomer (silicone or similar) with variable thickness (stiffness), located/fitted over
the inner end of each scoop cavity.
With Titanium density of 4.6 gr/cm³ the overall weight would be 4.78 kg. To reduce wear, it
could be coated with diamond via chemical vapor deposition (CVD), which would put it
above the 5.0 kg limit. If reducing wear is a high priority, drum width could be reduced to
suit and possibly still provide the minimum 17.5 Lt capacity.
The STL provided of the drum was just scaled up from that used to 3D print the plastic
model, so does not represent the actual wall thicknesses (mostly 0.8-1.0 mm) if printed at
full-size in Titanium. Nor does it show the flap configuration, or open/close mechanism.
Though not part of the competition, I have several other ideas related to the overall
RASSOR device, relating to seals, wheels and overall length.