User manual

Barrett Technology, Inc.
BA4-310 System User Manual Version 1.1
36
[ ] 3. Locate the horizontal slot at the top of the 2
nd
stage pulley surface. Feed the U-bend
loop of one cable from right to left until the loop appears on the inner diameter of the
pulley. Fit the U-bend around the termination post on the top flange.
[ ] 4. Take the U-bend of the other cable and place it through the slot and around the
termination post on the bottom flange. This termination leads the cable onto the bottom
of the base pulley outside diameter. Use a piece of tape to keep the loop in place and
exiting correctly until installation is complete.
[ ] 5. Being careful not to bind or pinch the cables, rotate the base joint fully counter-
clockwise (as viewed from above the arm) to its stop. Temporarily use tape to prevent
this joint from rotating freely. One or two short pieces on the outside of the robot,
between the stationary base structure and the rotating platter, should be sufficient.
[ ] 6. Make sure the ends of each parallel set of cables are still uneven by about 35mm. For
the cables starting from the top flange, the top cable should be longer. For the cables
starting from the bottom flange, the bottom cable should be longer. The reason for the
extra length is that the longer cable length will wrap an extra 1/2 turn around its
matching grooved pinion to its termination (the two pinion terminations are located 1/2
turn apart).
[ ] 7. Wrap the parallel set of cables from the bottom flange through the narrow gap between
the left pinion and the base pulley, around the base pulley one full turn, then under the
right pinion and under the left pinion a second time. Temporarily tape the cable set to
the pulley surface to keep the set in place.
Figure 17 - Base Joint 2
nd
Stage Cable Paths (top view)
[ ] 8. The cable attached to the base pulley top-flange should now be wound about ¼-turn
(above the other cable set) over the base pulley surface and through the narrow gap
between the right pinion and the 2
nd
stage pulley. Temporarily tape the cable set to the
pulley surface to keep the set in place.