User manual

Barrett Technology, Inc.

BA4-310 System User Manual Version 1.1

tools and cable parts have been gathered prior to any cabling activities, and good safety

precautions such as eye protection are utilized. The cabling instructions have numbered

checkboxes next to each step for tracking progress. These pages may only be photocopied for

use as a cabling checklist.

Allow roughly 6 hours to cable the entire wrist for the first time. Subsequent cabling of the

wrist after the user is familiar with the instructions can be completed in fewer than 2½ hours.

Often not all of the cables need to be replaced at once, thereby further reducing future re-

cabling times.

One important point to keep in mind is that each cable of a given drive must be held in place at

all times until the entire circuit is pre-tensioned. The wrapped cables act like light torsional

springs which, when released even momentarily, may quickly unravel your work back to your

starting point. This is the most common error for the first-time cabler. Pre-tensioning, which

prevents this unraveling, cannot be done until all cables in that circuit have been installed.

Regular 1/4-inch masking tape is a tremendous aid in temporarily preventing this unraveling.

As cables are wrapped onto each pulley or pinion, hold each wrap with your fingers to keep it

from unwinding. At the end of each cabling step, one or two pieces of masking tape

temporarily immobilize transmission elements and keep cables in place. Other helpful tools are

listed in Table 12.

Table 12 – Wrist Cabling Tools

Tool Use

¼-inch masking tape Temporarily secure cable wraps &

transmission elements

Blunt tweezers Manipulating cables in small spaces

3/32" hex torque-driver Pre-tensioning cable circuits

6.3 Differential Output (J5 & J6, M4 & M5)

The differential circuits are shown in Figure 31. They consist of four cables riding on four

different diameter horizontal steps. The four cables make up two circuits. The top horizontal

steps and the 2 smallest vertical steps form one circuit, and the bottom horizontal steps and the

2 larger vertical steps form the other circuit. Each circuit is tensioned with a worm gear located

in the vertical steps.