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Motion System Design
Inductive leap

Inductive leap

One way to sense linear displacement is through the relative movement of an optically grated glass scale. Another way is to monitor inductive variations along a string of tightly packed fine-tolerance ball bearings. Recently this latter method has been used to create an intelligent leadscrew, called ScrewCoder, that incorporates its own DSP-based feedback loop. The reference balls, which are encapsulated in a hollowed-out leadscrew, move in relation to a set of electromagnetic drive and pick-up coils positioned inside the “nut.” The passing of each ball produces a 0 to 360° phase shift that accurately corresponds to linear position.

Vital Stats

On display: ScrewCoder
Key features: Linear positioning device combines a mechanical drive screw with an inductive sensing mechanism that produces a standard quadrature output.
What it means to you: Rugged closed-loop position control in a single package.
What else: 10-μm accuracy; IP67 rating; shock and vibration resistant.
Innovator: Newall Electronics Inc.
For more info: Call (800) 229-4376 or visit

Got a grip

Setscrews and keys, typically used to hold torque-transmission components in place, are notorious for marring shafts and prohibiting easy removal and phase adjustment. To avoid these problems, a new line of spur gears employs a special slotted hub that serves as its own locking device. Two slots, one oriented radially the other angularly, form a transverse cantilevered wedge that acts like a vise when drawn in by a cap screw passing through one side of the hub. By tightening or loosening the screw, the spur gear can be adjusted as often as necessary without marring the shaft or affecting its ability to transmit torque.

Vital Stats

On display: Fairloc integral fastening system
Key features: Screw-activated wedge-cut hub applies uniform clamping pressure without damaging shaft.
What it means to you: Spur gears mount and dismount easily at any phase angle.
What else: Saves weight and space; resists corrosion (stainlesssteel construction); many gear sizes (4 to 10-mm shafts, 5 to 8-mm face widths, and 14 to 120 teeth).
Innovator: Quality Transmission Components
For more info: Call (516) 437-6700 or visit

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