Actuators for controlling multiple phase shifters of remote electronic downtilt base station antennas

Abstract

Multi-RET actuators include a plurality of shafts that have respective axially-drivable members mounted thereon. Each of axially-drivable member is mechanically linked to a respective one of a plurality of phase shifters. The multi-RET actuator further includes a motor having a drive shaft and a gear system that is configured to selectively couple the motor to the respective shafts. The gear system is configured so that rotation of the drive shaft in a first direction creates a mechanical linkage between the motor and a first of the shafts, and rotation of the drive shaft in a second direction that is opposite the first direction rotates the first of the shafts.

That which is claimed is: 
     
         1 . An actuator for a plurality of phase shifters, comprising:
 a plurality of shafts having respective axially-drivable members mounted thereon, each axially-drivable member configured to be connected with a respective one of the phase shifters;   a motor having a drive shaft; and   a gear system that is configured to selectively couple the motor to the respective shafts,   wherein the gear system is configured so that rotation of the drive shaft in a first rotative direction creates a mechanical linkage between the motor and a first of the shafts, and rotation of the drive shaft in a second rotative direction that is opposite the first rotative direction rotates the first of the shafts.   
     
     
         2 . The actuator of  claim 1 , wherein the gear system includes a forward-direction primary drive gear that is connected to the drive shaft and a reverse-direction primary drive gear that is connected to the drive shaft. 
     
     
         3 . The actuator of  claim 2 , wherein the forward-direction primary drive gear and the reverse-direction primary drive gear are each ratcheted gears that rotate in response to rotation of the drive shaft in the second rotative direction and which do not rotate in response to rotation of the drive shaft in the first rotative direction. 
     
     
         4 . The actuator of  claim 3 , further comprising a reversing gear that is configured to engage the reverse-direction primary drive gear and rotate in a direction opposite a direction of rotation of the reverse-direction primary drive gear. 
     
     
         5 . The actuator of  claim 4 , wherein the gear system further includes a plurality of secondary drive members mounted on respective ones of the shafts, each secondary drive member mounted so that rotation thereof will result in rotation of a respective one of the shafts. 
     
     
         6 . The actuator of  claim 5 , wherein the gear system includes an engagement mechanism that is configured to rotate to selectively and exclusively engage one or more of the shafts to move a selected one of the secondary drive members into engagement with one of the forward-direction primary drive gear or the reversing gear. 
     
     
         7 . The actuator of  claim 6 , wherein the engagement member comprises a rotating cam plate. 
     
     
         8 . A method of adjusting a phase shifter, the method comprising:
 rotating a drive shaft in a first rotative direction to connect a first of a plurality of gears to a drive mechanism;   rotating the drive shaft in a second rotative direction to rotate the drive mechanism, wherein rotation of the drive mechanism causes rotation of the first of the plurality of gears,   wherein rotation of the first of the plurality of gears mechanically adjusts a physical position of a component of the phase shifter.   
     
     
         9 . The method of  claim 8 , wherein the plurality of gears comprises a plurality of secondary drive gears that are configured to rotate respective shafts, and wherein the drive mechanism comprises a forward-direction primary drive gear that is connected to the drive shaft and a reverse-direction primary drive gear that is connected to the drive shaft. 
     
     
         10 . The method of  claim 9 , wherein the forward-direction primary drive gear is a ratcheted gear that only rotates in response to rotation of the drive shaft in a first rotative direction. 
     
     
         11 . The method of  claim 10 , wherein the reverse-direction primary drive gear is a ratcheted gear that only rotates in response to rotation of the drive shaft in the first rotative direction. 
     
     
         12 . The method of  claim 8 , wherein rotating the drive shaft in the first rotative direction to connect the first of the plurality of gears to the drive mechanism comprises using the rotating drive shaft to rotate a cam to move the first of the plurality of gears into operative engagement with one of the forward-direction primary drive gear or the reverse-direction primary drive gear. 
     
     
         13 . The method of  claim 8 , wherein at least one of the forward-direction primary drive gear or the reverse-direction primary drive gear is configured to engage the first of the plurality of gears through an intervening reversing gear. 
     
     
         14 . An actuator for a plurality of phase shifters, comprising:
 a motor that is configured to rotate a primary rotary member;   a plurality of axially-drivable members, each axially-drivable member mounted on a respective shaft, each axially-drivable member configured to be connected with a respective one of the phase shifters;   a plurality of secondary rotary members, each secondary rotary member mounted so that rotation thereof will result in rotation of a respective one of the shafts; and   a plurality of micro-motors, each micro-motor configured to rotate a respective one of the shafts.   
     
     
         15 . The actuator of  claim 14 , wherein the shafts comprise worm gear shafts. 
     
     
         16 . The actuator of  claim 15 , wherein the primary rotary member is a central gear and each of the secondary rotary members are gears. 
     
     
         17 . The actuator of  claim 16 , wherein the axially-drivable members comprise pistons. 
     
     
         18 . The actuator of  claim 14 , further comprising a plurality of springs that are mounted on the respective shafts, each spring configured to bias a respective one of the secondary rotary member toward a disengaged position where the secondary rotary member does not engage the primary drive member.