Front view of R.Max's left shoulder. A servo
needs to be added on the far left to "spin" the
hub, which will translate into arm-swinging front
and back motion. The red servo swings the
arm from down (current) to up above head.
The U-Joint is constrained to NOT spin in
one of it's axis by running the bolt directly
into the stop, effectively nulling one of the two
U-Joint centers of rotation. The bicycle wheel
hub is a Phil (model AVF800?). The U-Joint
is LoveJoy NB-6 (Needle Bearing 6) modified
by cutting the heavy ends off and welding a nut
on both ends. Costs: More than I like to admit!
Hub-$150.00, U-Joint (Modified)-$60 ($50)
= $110.00. Multiplex Jumbo mcV2 Servo -
$155.00. (I'm experimenting with cheaper
hubs too,but they're not as smooth spinning).
Why? I need very, very smooth rotation, and
the Phil Wood hub has it. The U-Joint has
needle bearings, so it's also smooth. This
servo is the highest torque servo I've found
yet, and if it's not strong enough, this design
allows me to double up.
Lovejoy, Inc, (708) 852-2120
Phil Wood, www.philwood.com