| Skewed bore in steering collar changes pulley angle as shaft turns. Feedback from a belt-position sensor, combined with a stepper motor could automatically adjust belt tracking.
| Steerable collars independently aim multiple pulleys on the same fixed shaft.
Engineers typically rely on pulley crowns, flanges, or timing elements to keep belts on track. While metal belts transmit mechanical power without stretching, outgassing, or building up static--conventional tracking methods may reduce belt life.
The independently steerable pulley (ISP) compensates for belt camber, differential loading, pulley-shaft deflection, or lack of system squareness without stressing belt material. Taking the guesswork out of tracking adjustments, ISP adjusts the pulley angle during operation, so you see the belt respond.
The steering collar, normally locked to the shaft, loosens to spin about the shaft. Rotating the collar makes the skewed or offset bore vary pulley-body angle relative to the belt. ISP claims include:
Faster belt-tracking adjustments
Minimized belt-replacement time
Special tools not required
Retrofits to existing idler pulleys
Longer belt life
Tim Potrikus, Belt Technologies, 11 Bowles Rd., Box 468, Agawam, MA 01001-0468; (413) 786-9922.
Multi-layer circuit board
A high-density PCB technology called Simov, for Siemens Multiple Overlayed Vias, packs more components into a smaller space. Drilled 300-micron via holes are the traditional way of connecting vias in a multilayer board. But they occupy precious space that cannot be used for components.
With Simov technology, the board is built up by overlaying successive layers of prepreg and copper foil. A laser beam drills blind holes to interconnect vias in adjacent layers. Resistors, screen-printed onto the Simov layers, further reduce component count on the top of the board, while capacitors can be created using a dielectric layer within the board's core.
These techniques allow the passive components to be
located closer to the pins of integrated circuits, providing better signal
decoupling at high frequencies.
| Apply photoresist, expose, develop, etch copper, strip photoresist, perform resistor screen printing. Add prepreg and copper foil. Use laser to melt copper and burn hole into dielectric until landing pad stops laser. Chemical and galvanic copper plating inside hole, onto Simov landing pad and onto copper foil. To finish first Simov layer: apply and develop the conductive pattern followed by etching.
| Precision laser drill shrinks via hole dimensions to just 120 microns. Result: twice as many components on the same real estate, higher clock rates, reduced mounting costs, and greater robustness.
Jennifer Kohl, Siemens, 2875 Northwoods Pkwy., Norcross, GA; (770) 797-3171.