User manual

Barrett Technology, Inc.
BA4-310 System User Manual Version 1.1
65
[ ] 7. Wrap the cable around the pulley 8 times using tape to hold the wraps if necessary.
[ ] 8. Transition over to the right 1
st
-stage pinion using an open-wrap. Attach the remaining
free end of the cable to the top (outer) termination of the pinion (which houses the
tensioner) and rotate the top segment of the pinion only. Maintain a slight axial force on
the outer pinion during this step so that the seam between it and the inner pinion does
not open. Guide the cable carefully to ensure that the cable winds on smoothly and
evenly. Rotate the pinion until the cable is tight.
[ ] 9. Insert the tensioner worm back into the motor pinion. To reach the worm bore, the user
may have to rotate the wrist axes slightly to bring it around into view. Be careful not to
lose tension in the 1
st
-stage cable at this point as your work will unwind back through
the 3
rd
-stage. Tighten the worm with the torque-driver to 0.23 N-m (32 oz-in).
[ ] 10. Pre-tension the circuit according to Section 6.4.3
6.4.3 Pre-tensioning Input Stages
Before pre-tensioning a particular cable circuit, the cables on the every stage of a transmission
should be positioned on the pulley and pinion, as shown in Figure 35. All of one cable should
be completely above the split in the pulley and below the split in the pinion while the other
cable is completely below the split in the pulley and above the split in the pinion. To achieve
the required cable positions, slowly back-drive the wrist until the cables properly align relative
to the split lines. When the cables are located correctly, the split surfaces of each pulley and
pinion can counter-rotate to allow the tensioner to propagate tension throughout the cable
circuit.