Check the unit when retracted and fully extended for misalignment and looseness. Either
condition will cause rapid wear and should be corrected immediately.
18.104.22.168 Linear Movement. Check the linear play. Linear play is the amount the top slide is
able to move freely, forward and back. This play must be kept to a minimum of approximately
3/8" or less.
22.214.171.124 Lateral Movement. Check the lateral play. The travel of each component within the
assembly must be parallel to within 0.005". The running parallelism of all components must be
maintained. One component operating just slightly out of line will put undo stress on the
complete system, greatly increasing wear.
126.96.36.199 Shifter Chain. Check the shifter chain. (See Figure 16-15). If the shuttle operation
appears sloppy, the drive chain springs and the intermediate chain clacks should be checked. The
drive chain should be adjusted to all (+/-) 1/16" play. Each of the intermediate chains should be
kept taut, allowing for the (+/-) 1/8" play with the shuttle in the extended position.
16.6.6 Shifter Drive
188.8.131.52 General. The shifter drive consists of a DC permanent magnet motor, a disc type brake
and a worm reducer. The complete assembly mounts on the carriage assembly.
184.108.40.206 Motor. Check the motor bearings for proper lubrication and vibration due to wear.
Check the interior of the motor for a build-up of dust or other foreign matter. Examine the
brushes for replacement and proper contact and the commutator for excessive wear and
220.127.116.11 Brake. Check the brake for evidence of mechanical failures, misalignment or other
18.104.22.168 Couplings. Check the couplings for tightness and proper contact.
22.214.171.124 Limit Switches. Check the side shifter limit switches.
126.96.36.199 Traveling Cables. Check the travel cables for proper fastening, twists or kinks, damage
due to chafing, intertwining, and clearance from hoistway equipment.