The LAEP and LABP 20, 40, 50 and 70 Series Gearboxes are the result of extensive research into current gearbox problems - specifically, bearing and seal failures - common in the field.

"The company applied this research, and designed a gearbox that not only offers solutions with current problems, but integrates improved efficiency, reliability and durability," Longwall Associates said in a statement.

The company said some of the major impediments with current gearboxes include reduced horsepower efficiency, inadequate cooling, and contamination of integral components. To provide improved equipment utilizing technological innovations, the company designed their gearboxes with the following features.

To rectify the inability of current gearboxes to achieve true horsepower the company claims to have designed a unique 3-planet set-up that allows the gearbox to achieve and maintain the true rated, veritable, horsepower effectively and consistently.

The risk of gearbox failures associated with lubrication has been reduced by designing a gearbox that relies on splash rather than a pump. Also, the gear case is fashioned to allow a higher volume of oil flow through high temperature zones.

To further reduce problems with overheating, a modernised cooling system twice the length of other models was designed and tested at 1160 psi.

Longwall Associates said the increased length has resulted in a 20 degree Fahrenheit reduction in temperature during trial runs. As a result, the design prevents oil from overheating, wherein the oil maintains its chemical properties.

To reduce problems associated with contamination, the output shaft sealing is comprised of a grease filled labyrinth designed to purge contaminated material away from the output shaft.

"Both models offer a myriad of other features," the company said. "A sampling of these other features are overhung load problems, noise reduction and interchangeability. These, amongst other features, were strategic elements in the design of Longwall Associates series gearboxes."

To combat problems with overhung load on gearboxes and subsequent failures, the LABP and LAEP are designed with maximized center distance between the input bearings to provide greater stability of the gearbox and discourage associated failures. Additionally, the company integrated spherical rollers at the input shaft to prevent roller skid under no load conditions.

In an attempt to reduce the noise the company integrated special gears for a quiet, smooth operation.

Longwall Associates said it has designed its gearbox line to be directly interchangeable with other manufacturer's gearboxes, eliminating the need to remachine drive frames. Additionally, components of both the LAEP and LABP are interchangeable, reducing certain spare parts requirements.

The LAEP and LABP series gearboxes are currently being installed in a Jim Walter Resources mine in Alabama, US.