Drives and Controls Magazine

Interest heats up in belt-based gear rival

01 October, 2001

Interest heats up in belt-based gear rival

John Hammerbeck, the inventor of a new belt-based form of mechanical speed control that could replace gears, has come up with a new use for his Scram (simple continuous ratio adjusting machine) technology. He suggests using it to recover waste heat from motors and engines, cutting their energy consumption by up to 10%.

The Scram system is a simple, low-cost device that uses an extendable belt to provide reduction, clutching, continuously variable speed control, and an automatic response to power demand. It has only ten moving parts and a ratio range of 1:1 to 18:1.

Since Drives & Controls first reported on the technology – also known as a periodic belt – year ago (September 2000), Hammerbeck has been contacted by various potential licencees. A Chinese company is building a prototype which it believes could have widespread applications on the long conveyor belts that carry ore from mines. If the prototype performs as predicted, the company could start to sell the technology as a replacement for geared reducers next year.

Also in the Far East, a Korean company is looking at using the Scram technology on marine engine installations.

Hammerbeck has applied for a patent for his new proposal that combines the periodic belt principle with that of the thermal belt engine. These engines use thermally deformable memory metals, or bimetallic strips, to turn low-grade heat into useful rotational work. Although considerable research has been down on these engines, no useful products have yet emerged because of their cost, their low output speed and the difficulty in starting them.

Hammerbeck believes that his Scram technology could overcome these drawbacks. He suggests using a thermally deformable belt which would absorb heat during its pulling phase and dissipate it during the return phase, resulting in an increased torque on the output pulley. He has yet to test this idea and admits that the proposal is "purely theoretical at present".

In one potential application, he envisages feeding a belt through a motor with a hollow central shaft to recover heat that would otherwise be lost. "If you get an extra ˝% of efficiency, it would more than pay for itself," he argues.