The Rockford Preload (RP) ball screw assemblies consist of two standard ball nut
assemblies and a rolled thread ball screw. The preload is accomplished by forcing
the balls of each nut on opposing flanks of the ball screw thread. Wavy washer
or bevel spring packs are used to provide this resulting force. There are no
shims to grind or replace. The preload ball screws exhibit only a light
reduction of overall effieciency and load-carrying capacity versus standard
ball screws. These preloaded ball nuts are being used in a large number
of industrial and commercial applications where precise positioning
is obtained by other means than read-out of the screws. These
low-cost units are being used in many N/C-controlled machine
tools where a secondary control system is used for positioning.
These systems nclude laser, optical positioning, magnetic
(pin or tape indexing) and positive stops. The RP preload
is adjustable and is accomplished by loosening the set
screws and turning the collar with a spanner wrench
and retightening the set screw.
