Adjustable Speed Drives

A unique mechanical variable speed transmission drive



Adjustable Speed Drives



Adjustable Speed Drives

- Compact and easy to handle.


- Simple to install. No special wiring or training.


- Easy to operate with lever or screw control. Repeatable


- Use adjustable speed drives anywhere on machine. Accepts input to 2,000 RPM. Ideal secondary controller.


- Delivers constant torque throughout the speed range.


- 4:1 speed reduction. Drive is often usable without additional speed reduction.

Low Cost & Proven Design.

More than 1,000,000 sold.


Ideal for users and original equipment manufacturers


Adjustable Speed Drives

Low cost and proven design. More than 1,000,000 sold.


It all began in 1949, when Minnesota inventor Sterling Stageberg designed a unique mechanical variable speed transmission drive. Stageberg's design varied the output speed from a constant input from zero to maximum.

Initially, it was used on automotive windshield wipers and became an instant success


The general principle of operation of Adjustable Speed Drives gives infinitely variable and adjustable speed by changing the distance that four or more one-way clutches rotate the output shaft when they move back and forth successively.



Adjustable Speed Drives

Adjustable speed drive speed adjustments are easily made by moving a lever control through an arc or turning the hand-wheel of a screw type control. In either case, easy and precise speed control settings are possible with Zero-Max adjustable speed drives.


For lower speed/higher torque applications, some Zero-Max drives are available with our right angle gearbox. Some Zero-Max drives may be purchased with standard electric motors or they may be connected to any rotating power source up to 2000 RPM.


Externally, the Adjustable Speed Drive consists of a rugged, sealed cast case, an input shaft, output shaft and adjustable speed control. Speed of the output shaft is regulated precisely and easily through a control lever which includes a convenient locking mechanism or a screw control to hold speed at a desired speed setting.


Adjustable speed drive models are available with output in clockwise or counter-clockwise rotation to meet individual speed control requirements. Two models are equipped with a reversing lever that permits clockwise, neutral and counter-clockwise operation.


Permits slow or fast, small or large speed changes. Speed set-ups are made quickly and easily. Ideal for dancer applications / constant speed changes.




- Leave drive at one setting. No daily speed cycling.


- Accurate speed holding. No "wear-in" period / constant speed operation.


- Zero-Max adjustable speed drives accepts any input. It's the world's most versatile, economical secondary drive.


- Goes to zero output. Ideal for use as a clutch.


- Simple maintenance. Factory lubricated.


- Ideal for users and original equipment manufacturers.


- Sealed housing. Use in most atmospheres. Can be mounted in any position.


- Versatile shaft / control / motor options.


- Infinitely adjustable. 0-400 RPM speed range with 1800 RPM input.

Download Catalog:



Main Catalog

Wind Turbine Parts:

Adjustabble Speed Drives


Coupling Composite Disc(comming soon)

Overhung Load Adaptors


Torque limiters(comming soon)

Cardan shafts(comming soon)

Composite Disc Couplings

Wind turbine Parts(comming soon)

Linear Actuators

ServoClass Couplings


Overload Safety Device

MEGIFlex Couplings



Schmidt Coupling

SITI Gears(comming soon)

Back-Run Safety Mechanisms(comming soon)

Control Flex Couplings

Crown Gear

Spur Gear and Racks

Habix Coupling


Locking Assembly Shrinck Disc

Flex Tire Coupling


Phase Adjusting Hubs

HRC Coupling(comming soon)



ALS Coupling