Having spent a bit of time contemplating the Sportsman idea, we need to spend a serious amount of time with Rhino3D to see if the design in our heads has even the slightest chance of being build-able. We've already started messing around with the legs, so here's some work on another part of the 'bot: the tail! Scorpions have a sting in their tail, and this 'bot - despite being Cyber - should do the same ... Hit Back after viewing an image.
Using what we learned last time we tried to design a hinged joint, we were pretty quickly able to throw together this structure for the tail. It's not entirely finished, as you can see there are parts that still project into each other, but that's because we want to mock up the joint in the
garage Build Space and see what the easiest way is of limiting the range of motion of each joint to 30 degrees.
Here we've straightened out the tail and installed double-sprockets on the hinge axles. These are nylon 16-tooth #25 sprockets that will be bored to 'float' on the axles and are pinned together. The idea is to power the bottom (far-right) pair from a motor, and have the movement be transmitted to the end of the tail (bottom-left). Granted, there will be some losses, but this way we can allow the tail to articulate without having chain slopping everywhere.
Okay - here's the 'sting': a 12" SystiMatic Demolition blade! Long-time readers may remember that we used these on our very first 'bot ever, way back when. Whew! That brings back some memories!
As far as the articulation goes, to make the tail bend, we will run some thin steel cable from a fixed point at the sting-end of the tail through eyelets mounted on the underside, all the way back to the base of the tail, where the cable will be wound by a drill motor. The easiest thing to do here is to leave the clutch on the drill motor, so that when the cable is fully tightened and the tail is fully arched, the drill will simply slip the clutch. To straighten the tail, there will be springs mounted to the upper-side of each segment, so as the drill unspools the cable, the springs contract, pulling the tail straight. Well ... that's the theory anyhow.
Finally for now, a quick render with the legs and the tail together. Well ... I say quick - it took my machine eight minutes to produce this render! And no guarantees that this will be the final layout - we haven't even started calculating how much just the pieces you see here weigh ... there is a slight possibility that this is an impossible task, even with the 100% weight bonus for a walker, but it's definitely worth investigating ...