Kerk Motion Product's 4000 Series ScrewRail combines drive, support, and guidance, in a single, compact unit. The arrangement eliminates external rail-to-screw alignment, an expense item for typical two-rail systems. A proprietary coating also eliminates external lubrication and can extend nut life by more than a factor of three. CD/DVD duplicators from Amtren use the ScrewRail product to lift and rotate an all-mechanical pickarm.


ScrewRail actuators from Kerk Motion Products, Hollis, N.J. (, help simplify design of automated CD/DVD duplicators and halve costs compared with previous systems.

The duplicators from Amtren Corp., Montgomery, Ala. (, use the ScrewRail product to lift and rotate a special, all-mechanical pickarm assembly. The pickarm lifts blank disks (by the center hole) from a stack, rotates into position, and drops them into a CD/DVD burner. It removes the copied disks then shuttles them to an output stack. Some duplicator models also transfer copied disks to a printer.

One key to making it all work is a leadscrew-driven gear in the pickarm. Amtren's previous design used a machined gear held in place with set screws. But the arrangement required the drilling of holes for alignment and positioning, a difficult and sometimes imprecise process. In response, Kerk engineers designed an improved injection-molded gear that aligns automatically to the actuator rail. Amtren simply presses the gear onto the rail and snaps in a few parts, eliminating the need for alignment.

"Kerk's ScrewRail and updated gear help our equipment make millions of CD and DVD copies with zero maintenance or adjustment," says Amtren Design Engineer John Klein.