A hydraulic capstan drive helps keep barriers evenly spaced, despite hils and curves, which tend to space barriers too close together or too far apart.Capstan counteracts gravity
During normal operation, gravity can cause the barriers to migrate backward or forward from inclines and declines in the road surface. For example, barriers will tend to migrate down a hill or resist angular repositioning around a curve. This movement results from gravity and rolling resistance within the machine as the barrier passes through the series of rollers. Spring forces in the hinge assemblies between each barrier can also contribute for positioning error.
A capstan drive works to counteract these tendencies. The capstan drive consists of a hydraulic motor, two pumps, two rubber capstan wheels mounted under the machine, and controls. Without the capstan drive, barriers would tend to be spaced too far apart or too close together at the beginning and end of hills, valleys, and curves. The result would be excessive tensile or compressive stress on the hinges. The capstan compensates for irregularities to maintain the wall in a neutral, stable position.
The Road Zipper and Road Zipper System (which includes the interlocked median barriers) are manufactured by Barrier Systems Corp., a division of Lindsay Transportation Solutions, Omaha, Neb. For more information, visit www.barriersystemsinc.com.