Roto-Lok® Drive System and Antenna Positioners

POINTING ACCURACY, STABILITY, AND SPEED OF MOVEMENT

The most important of specifications for a satellite antenna, particularly an auto-acquisition antenna, is the pointing accuracy and the stability and stiffness of the positioner under the most extreme environmental conditions. The positioning accuracy is determined by how precisely the positioner can move to a defined point as well as how stable and stiff the positioner is in maintaining that position. The speed of movement is based on how quickly the positioner can move to a defined position.

AvL's patented Roto-Lok® cable drive technology provides the ultimate in precision and stiffness compared to geared drive systems and, unlike most other systems, is free of backlash. It is a maintenance-free dry mechanism able to operate in a very wide range of difficult and hazardous conditions without degradation. Originally invented as an expensive way to rotate very large antennas accurately and smoothly, the Roto-Lok® is an elegantly simple system that utilizes the averaging effect of many cables wrapped around a drive capstan and output shaft.

HOW IT WORKS

The drive capstan and the output drum are connected by multiple precision stell aircraft cables. The cables share the load, each with a tension spring at one end and a fixed mounting point at the other. The drive carries torque through the friction of the cables on the drum and capstan. The springs maintain constant design tension on each cable. Because the Roto-Lok 7 drive is constantly pre-loaded in both directions, there is absolutely no backlash. Unlike gears that have inherent backlash and also wear and degrade performance, the springs keep the proper tension indefinitely, resulting in "like new" performance throughout many millions of cycles. It requires no lubrication and is virtually maintenance free. The many cables serve to average the rotation rate so that imperfections, dirt or other slight irregularities on a single cable or drum do not have any significant effect, resulting in superb drive smoothness with no clogging or drive rate irregularity. Therefore, the Roto-Lok® cable drive provides efficiency in excess of 99%.

BENEFITS

• Backlash Free and High Stiffness
• Precise and Smooth Positioning
• Minimal to Non-Existant Cable Wear from Sliding or Streching
• High Efficiency Resulting from Smaller Motors, Wiring and Power Supply
• Shock and Vibration Resistant
• No Lubrication Necessary
• Lighter Weight

© 2005 AvL Technologies, Inc. All Rights Reserved.