90 ton 1/14 metal excavator scratch build w/embedded PC

[SteinHDan]

Mounting the boom

I'm going to try to use electric gear motors first. If that doesn't work out, I'll make the excavator hydraulic instead.

I'm using some quite powerful gear motors for all of the joints.
Ebay link:
- http://www.ebay.com/itm/221515025957

These are 10 rpm 320 kg / cm stall torque motors. Two in parallel should produce 640 kg / cm.




The two motors mount to the upper structure with 8 M5 countersunk bolts.






The boom itself is constructed with two milled 6mm aluminum profiles. At the end, another gear motor is mounted with another 8 M5 countersunk bolts.

I bought the hubs on aliexpress:
- http://www.aliexpress.com/item/10mm-...922964248.html












I'm using gas springs where the hydraulic cylinders would normally go.
The gas springs functions in many interesting ways in this configuration:
- Equalize the weight of the arm, so that the gear motor only have to lift the payload
- Dampen sudden movements and protect the gear motor
- A sound that is similar to a hydraulic cylinder
- Visually resembles a hydraulic cylinder.




Item links:
- Gas springs: http://www.ebay.com/itm/181788326018
- Clevis: http://www.ebay.com/itm/161559757356
- Rod eyelet: http://www.ebay.com/itm/5mm-Female-T...-/181888111312