Actuators for controlling multiple phase shifters of remote electronic downtilt base station antennas
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 1340/1342 , and rotation of the drive shaft in a second direction that is opposite the first direction rotates the first of the shafts.
1. An actuator for a plurality of phase shifters, comprising:
a plurality of axially-drivable members, each axially-drivable member mounted on a respective parallel shaft, the axially-drivable members configured to be connected with a respective one of the phase shifters;
a central drive member;
a plurality of rotary members, each mounted on a respective one of the parallel shafts;
wherein each of the rotary members is axially movable between an engaged position, in which the rotary member engages the central drive member, and a disengaged position, in which each rotary member is disengaged from the central drive member;
an engagement mechanism that is configured to rotate to selectively and exclusively engage each of the shafts to move a respective rotary member to the engaged position;
a first drive unit to drive the central drive member; and
a second drive unit configured to drive the engagement mechanism,
wherein the engagement mechanism comprises a cam that engages one of the parallel shafts to move a respective rotary member attached to the shaft to the engaged position.
2. The actuator defined in claim 1 , wherein the axially-drivable members comprise pistons.
3. The actuator defined in claim 1 , wherein the parallel shafts comprise worm gear shafts.
4. The actuator defined in claim 1 , wherein the parallel shafts include spring-loaded shafts that bias the rotary members toward the disengaged position.
5. The actuator defined in claim 1 , wherein the engagement mechanism includes a ring gear, and wherein the ring gear engages the second drive unit.
6. The actuator defined in claim 1 , wherein the central drive member is a central drive gear.
7. The actuator defined in claim 1 , wherein the rotary members are gears.
8. An actuator for a plurality of phase shifters, comprising:
a plurality of axially-drivable members, each axially-drivable member mounted on a respective parallel shaft, the axially-drivable members configured to be connected with a respective one of the phase shifters;
a central drive gear;
a plurality of gears, each mounted on a respective one of the parallel shafts;
wherein each of the gears is axially movable between an engaged position, in which the gear engages the central drive gear, and a disengaged position, in which each gear is disengaged from the central drive gear;
an engagement mechanism that is configured to rotate to selectively and exclusively engage each of the shafts to move a respective gear to the engaged position;
a first drive motor to drive the central drive gear; and
a second drive motor configured to drive the engagement mechanism,
wherein the engagement mechanism includes a ring gear, and wherein the ring gear engages the second drive motor.
9. The actuator defined in claim 8 , wherein the axially-drivable members comprise pistons.
10. The actuator defined in claim 8 , wherein the parallel shafts comprise worm gear shafts.
11. The actuator defined in claim 8 , wherein the parallel shafts include spring-loaded shafts that bias the gears toward the disengaged position.
12. The actuator defined in claim 8 , wherein the engagement mechanism comprises a cam that engages one of the parallel shafts to move a respective gear attached to the shaft to the engaged position.
13. An actuator for a plurality of phase shifters, comprising:
a plurality of axially-drivable members, each axially-drivable member mounted on a respective parallel shaft, the axially-drivable members configured to be connected with a respective one of the phase shifters;
a central drive gear;
a plurality of gears, each mounted on a respective one of the parallel shafts;
wherein each of the gears is axially movable between an engaged position, in which the gear engages the central drive gear, and a disengaged position, in which each gear is disengaged from the central drive gear;
a cam plate with a cam, the cam plate being configured to rotate such that the cam selectively and exclusively engages each of the shafts to move a respective gear to the engaged position;
a first drive unit to drive the central drive gear; and
a second drive unit configured to drive the cam plate.
14. The actuator defined in claim 13 , wherein the axially-drivable members comprise pistons.
15. The actuator defined in claim 13 , wherein the parallel shafts comprise worm gear shafts.
16. The actuator defined in claim 13 , wherein the parallel shafts include spring-loaded shafts that bias the gears toward the disengaged position.
17. The actuator defined in claim 13 , wherein the cam plate includes a ring gear, and wherein the ring gear engages the second drive unit.