Surface treatments do not interfere with the scrolling motion of the scroller assembly and can add to the variety of functions possible. Unlike the polished smoothness needed for conventional bearings, scroller rollers and belts can have:

• grooves
• etching
• ridges
• flex coating
• teeth
• traction patterns
• etc.

As shown in Figure 5, each roller 35 may include an annular element to receive and engage the roller band. For example, a groove 19 in the roller having a smooth concave surface constrains the roller band in the groove and centers the band within the groove as the band rolls over the groove. Appropriate roller bands for such a groove include tubes, cables, and woven materials that seat in the groove. Similarly, a roller band tube 20 may be inflatable, fluid filled or formed of a spongy material, to provide roller separation and a cushion between the rollers. Alternatively, an annular rib 36 in an annular groove 38 on a roller may be used to support the middle of a roller band and center the band over the rib 36. In addition, the rollers in an annular area for the roller bands may be scored in a cross-hatched pattern (40) to provide good traction between the band and rollers, especially in wet conditions where traction may be difficult to maintain.
Link: ScrollerWheel Patent

Fig.67
(Link: Load, static)