KMI Mini Case-Study- QTec

One of KMI’s patented long-standing innovations is its “hour-glass” worm technology, increasing the number of gear teeth engaged with the worm thread. This design significantly improves the force distribution of the drive’s tooth mesh, which results in higher torque capacity for a given physical size, as well as better positioning accuracy and rotational smoothness.

A significant benefit of the KMI design was recently demonstrated in the field by a utility customer located in Finland and supported by QTec. QTec supplies the utility with slew drives to support an application that combines the functionality of a backhoe & pole handler. The customer’s machines efficiently bury overhead utility lines by first, lifting and removing the utility poles and second, digging the trenches for the underlying cable. On a recent project, the utility company was in urgent need of nineteen slew drives to support its machinery.

As a quick start, the utility chose to make use of existing, on-hand, competitor supplied slew drives, to fill the gap of whatever KMI drives QTec couldn’t deliver in the short-term.  The outcome included a roughly even mix of equivalently sized slew drives  – as needed to fit into the customer’s design space. Although the drives were the same physical size, the KMI drive specification had a significantly higher value for backward holding torque (BHT) due to the hour-glass worm technology. The operator, when unearthing the poles, occasionally grasped them too far from their center of gravity, applying torque levels that far exceeded what was targeted.  Over the course of this project, all of the KMI LP17 slew drives outlasted the competitor’s drives. All of the competitor’s slew drives sustained fatal damage.

Although it is critical to specify the correct performance requirements for a slew drive application, sometimes existing design constraints limit the physical size of the gearbox. The KMI hour-glass design allows more holding torque to fit into a smaller, lower profile package than other gear designs.

KMI has more than one million slew drives installed around the world. KMI has over 60 patents that enable efficient, effective, and competitive solutions to industrial equipment challenges. These compact rotary motion gears are used in applications ranging from state-of-the-art solar trackers to construction cranes and industrial automation. More than twenty years of field experience is the foundation of KMI’s technology and product innovation.