Interchangeable gear mechanism for base station antennas

Abstract

This disclosure relates to a shiftable transmission mechanism for a base station antenna. The shiftable transmission mechanism includes: a plurality of axially drivable members, each axially drivable member mounted on a corresponding transmission rod among a plurality of parallelly arranged transmission rods and configured to connect to a corresponding phase shifter among a plurality of phase shifters in the base station antenna; a transmission unit including a first gear assembly and a second gear assembly throttlely connected to the first gear assembly, wherein the second gear assembly is capable of engaging or disengaging with any transmission rod via a rod adapter movable along an axial direction between an engaged position and a disengaged position; and a shifting unit configured to move the second gear assembly in a lateral direction perpendicular to the axial direction when the second gear assembly disengages from the transmission rod, thereby enabling the shiftable transmission mechanism to selectively drive any transmission rod. The shiftable transmission mechanism of this disclosure comprises a small number of components, has a simple structure, and is low in cost.

Description

Technical Field

[0001] This disclosure generally relates to communication systems. More particularly, this disclosure relates to a shiftable transmission mechanism for a base station antenna. Background Technology

[0002] Cellular communication systems are used to provide wireless communication to fixed and mobile users. A cellular communication system may include multiple base stations, each providing wireless cellular service to a designated coverage area (often referred to as a "cell"). Each base station may include one or more base station antennas for transmitting radio frequency ("RF") signals to and receiving RF signals from users located within the cell served by that base station. Base station antennas are directional devices capable of concentrating RF energy transmitted or received from certain directions.

[0003] Modern base station antennas typically comprise two, three, or more linear (or planar) arrays of radiating elements, each with an electronically adjustable downtilt angle. The linear arrays often include cross-polarized radiating elements and are equipped with individual phase shifters for electronically adjusting the downtilt angle of the antenna beam for each polarization, allowing the antenna to include twice the number of phase shifters as the linear arrays. Remotely adjustable tilt (“RET”) actuators and associated actuation mechanisms can be incorporated into the antenna to adjust the phase shifters.

[0004] Conventionally, each phase shifter is equipped with a separate RET actuator, resulting in a base station antenna comprising multiple RET actuators, significantly increasing the size, weight, and cost of the base station antenna. So-called "multi-RET actuators" are also known, which can selectively adjust one of multiple phase shifters via a shiftable actuation mechanism. However, the shiftable actuation mechanism used in conventional "multi-RET actuators" typically contains a large number of parts, which increases the size and complexity of the shiftable actuation mechanism. Summary of the Invention

[0005] One of the objectives of this disclosure is to provide a shiftable transmission mechanism for a base station antenna that overcomes at least one defect in the prior art.

[0006] According to one embodiment of this disclosure, the shiftable transmission mechanism for a base station antenna includes: a plurality of axially drivable members, each axially drivable member being mounted on a corresponding transmission rod among a plurality of parallelly arranged transmission rods and configured to be connected to a corresponding phase shifter among a plurality of phase shifters in the base station antenna; a transmission unit including a first gear assembly and a second gear assembly throttlely connected to the first gear assembly, wherein the second gear assembly is capable of engaging or disengaging with any transmission rod via a rod adapter movable along an axial direction between an engaged position and a disengaged position; and a shifting unit configured to move the second gear assembly in a lateral direction perpendicular to the axial direction when the second gear assembly disengages from the transmission rod, so that the shiftable transmission mechanism can selectively drive any transmission rod.

[0007] According to one embodiment of this disclosure, the first gear assembly and the second gear assembly are arranged at substantially the same height.

[0008] According to one embodiment of the present disclosure, the first gear assembly includes a first gear and a second gear meshing with each other, and the second gear assembly includes a third gear and a fourth gear meshing with each other, wherein the third gear is tractively connected to the second gear via a drive shaft extending along the lateral direction, the drive shaft having a non-circular outer peripheral shape.

[0009] According to one embodiment of this disclosure, the central axis of the first gear is perpendicular to the central axis of the second gear.

[0010] According to one embodiment of this disclosure, the first gear is a bevel gear, and the second gear includes a bevel gear portion that meshes with the first gear.

[0011] According to one embodiment of this disclosure, the central axis of the third gear is perpendicular to the central axis of the fourth gear.

[0012] According to one embodiment of this disclosure, both the third gear and the fourth gear are bevel gears.

[0013] According to one embodiment of this disclosure, the third gear and the fourth gear are rotatably held in a gear holder, such that the third gear and the fourth gear are capable of lateral movement in response to lateral movement of the gear holder.

[0014] According to one embodiment of this disclosure, the gear retainer is made of plastic and includes an upper body and a lower body.

[0015] According to one embodiment of this disclosure, the shiftable transmission mechanism includes a guide rod for guiding lateral movement of the gear retainer.

[0016] According to one embodiment of the present disclosure, the first gear is configured to be driven by a first motor.

[0017] According to one embodiment of this disclosure, the fourth gear is configured to engage or disengage with any one of the drive rods via the rod adapter.

[0018] According to one embodiment of this disclosure, the rod adapter is rotatably clamped in a rod adapter retainer, such that the rod adapter is axially movable between the engaged position and the disengaged position in response to axial movement of the rod adapter retainer, and is laterally movable in response to lateral movement of the rod adapter retainer.

[0019] According to one embodiment of this disclosure, the rod adapter retainer is made of plastic and includes an upper body and a lower body.

[0020] According to one embodiment of this disclosure, the shiftable transmission mechanism includes a screw for driving the lever adapter retainer to move it laterally.

[0021] According to one embodiment of this disclosure, the shiftable transmission mechanism further includes a guide rod for guiding the lateral movement of the lever adapter retainer.

[0022] According to one embodiment of the present disclosure, the shifting unit includes an axial drive assembly and a lateral drive assembly, wherein the axial drive assembly is configured to move the lever adapter in an axial direction between the engaged position and the disengaged position, and the lateral drive assembly is configured to drive the second gear assembly in the lateral direction when the lever adapter is disengaged from the drive rod.

[0023] According to one embodiment of this disclosure, the lateral drive assembly includes an axially movable slide plate and a drive shaft for axially moving the slide plate, the slide plate being configured such that, upon axial movement, the rod adapter moves axially between the engaged position and the disengaged position.

[0024] According to one embodiment of this disclosure, the drive shaft is configured to be driven by a second motor.

[0025] According to one embodiment of this disclosure, one end of the drive shaft is threadedly connected to the end face of the sliding plate to cause the sliding plate to move axially when the drive shaft rotates, and the other end of the drive shaft is provided with a spur gear, which meshes with another spur gear mounted on the end of a motor adapter, so that the second motor drives the drive shaft via the motor adapter.

[0026] According to one embodiment of this disclosure, the lateral drive assembly includes a third gear assembly configured to laterally move the rod adapter by rotating a drive screw.

[0027] According to one embodiment of this disclosure, the third gear assembly is configured to be drive-connected to the first gear assembly, such that the third gear assembly and the first gear assembly are driven by the same drive device.

[0028] According to one embodiment of this disclosure, the third gear assembly includes a fifth gear and a sixth gear, wherein the fifth gear and the sixth gear are engaged with each other when the rod adapter is disengaged from the drive rod, and the fifth gear and the sixth gear are disengaged from each other when the rod adapter is engaged with the drive rod.

[0029] According to one embodiment of this disclosure, both the fifth gear and the sixth gear are spur gears.

[0030] According to one embodiment of this disclosure, the pitch of the screw can be selected to obtain the desired lateral movement speed of the rod adapter.

[0031] According to one embodiment of this disclosure, the first gear, the second gear, the third gear, the fourth gear, and the drive shaft are all made of plastic.

[0032] According to one embodiment of this disclosure, the fifth gear, the sixth gear, and the screw are all made of plastic.

[0033] According to one embodiment of this disclosure, the shiftable transmission mechanism includes a locking mechanism configured to prevent the transmission rod from rotating when the rod adapter is disengaged from the transmission rod, so as to avoid changing the phase angle of the phase shifter.

[0034] According to one embodiment of the present disclosure, the locking mechanism includes a bushing mounted on one end of each transmission rod, each bushing including a flange, the side of the flange being provided with a plurality of keys distributed along the circumferential direction of the flange and extending along the axial direction of the bushing, the keys being configured to engage with keyways provided on the frame of the shiftable transmission mechanism to achieve locking.

[0035] According to one embodiment of this disclosure, the locking mechanism includes an elastic member that, when the rod adapter disengages from the transmission rod, automatically pushes the bushing along the axial direction to the position where the key mates with the keyway.

[0036] It should be noted that aspects of this disclosure described with respect to one embodiment can be included in other different embodiments, although these other different embodiments are not specifically described. In other words, features of all embodiments and / or any embodiments can be combined in any manner and / or combination, as long as they do not contradict each other. Attached Figure Description

[0037] Many aspects of this disclosure will be better understood after reading the following detailed description in conjunction with the accompanying drawings, in which:

[0038] Figure 1 A perspective view of a shiftable transmission mechanism for a base station antenna according to an embodiment of the present disclosure is shown.

[0039] Figure 2 A partial perspective view of a shiftable transmission mechanism for a base station antenna according to an embodiment of the present disclosure is shown.

[0040] Figure 3 and Figure 4 The specific structure of a transmission unit for a shiftable transmission mechanism for a base station antenna according to an embodiment of the present disclosure is shown.

[0041] Figure 5 A perspective view of a gear retainer according to an embodiment of the present disclosure is shown.

[0042] Figure 6 A perspective view of a rod adapter retainer according to an embodiment of the present disclosure is shown.

[0043] Figure 7 A perspective view of a shifting unit of a shiftable transmission mechanism for a base station antenna according to an embodiment of the present disclosure is shown.

[0044] Figure 8 A partial perspective view of the axial drive assembly of a shift unit according to an embodiment of the present disclosure is shown.

[0045] Figure 9 A partial perspective view of the lateral drive assembly of a shift unit according to an embodiment of the present disclosure is shown.

[0046] Figures 10 to 12 The specific structure of a locking mechanism for a transmission rod according to an embodiment of the present disclosure is shown.

[0047] It should be understood that the same reference numerals denote the same elements in all the accompanying drawings. For clarity, the dimensions of some features may be altered and they may not be drawn to scale. Detailed Implementation

[0048] The present disclosure will now be described with reference to the accompanying drawings, which illustrate several embodiments of the present disclosure. However, it should be understood that the present disclosure can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure more complete and to fully illustrate the scope of protection of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide further additional embodiments.

[0049] It should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit this disclosure. All terms used in this specification (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0050] Unless otherwise specified, the singular forms “a,” “the,” and “the” used in this specification include the plural forms. The terms “comprising,” “including,” and “containing” used in this specification indicate the presence of the claimed feature but do not exclude the presence of one or more other features. The term “and / or” used in this specification includes any and all combinations of one or more of the relevant listed items.

[0051] When a component is described in the specification as being "on", "attached" to, "connected" to, "joined" to, or "in contact" with another component, the component may be directly located on, attached to, connected to, joined to, or in contact with the other component, or there may be an intermediate component present.

[0052] In this specification, the terms "first," "second," "third," etc., are used for ease of explanation only and are not intended to be limiting. Any technical feature represented by "first," "second," "third," etc., is interchangeable.

[0053] In the specification, spatial relation terms such as "above," "below," "front," "back," "top," and "bottom" describe the relationship between one feature and another in the accompanying drawings. It should be understood that spatial relation terms include not only the orientation shown in the drawings but also the different orientations of the device during use or operation. For example, when the device in the drawings is inverted, a feature previously described as "below" other features can now be described as "above" other features. The device can also be oriented in other ways (rotated 90 degrees or in other orientations), in which case the relative spatial relationships will be interpreted accordingly.

[0054] Reference Figure 1This illustration shows a shiftable transmission mechanism 10 for a base station antenna (especially a multi-band base station antenna) according to an embodiment of the present disclosure. The shiftable transmission mechanism 10 is used to adjust one of a plurality of phase shifters in the base station antenna to adjust the pointing angle (e.g., elevation angle or "downtilt" angle) of the antenna beam generated by the base station antenna. The shiftable transmission mechanism 10 may include a plurality of parallel transmission rods 101, each transmission rod 101 being mounted with a corresponding axially drivable member 102 configured to move axially along its associated transmission rod 101. Each axially drivable member 102 may be connected to a movable element of a corresponding phase shifter to adjust the phase shifter's settings by axial movement of the axially drivable member 102. Figure 1 In the illustrated embodiment, the drive rod 101 is shown as a screw, while the axially drivable member 102 is shown as a piston with a rod clamp. One end of a corresponding mechanical link (not shown) can be connected to the piston via the rod clamp, while the other end can be directly or indirectly connected to the movable element of the corresponding phase shifter. The presence of the mechanical link prevents the piston from rotating in response to the rotation of the screw. The piston may have internal threads to engage with external threads on the corresponding screw. Therefore, the piston can be configured to move axially back and forth on the screw as the screw rotates, thereby moving the movable element of the corresponding phase shifter to adjust the downtilt angle of the antenna beam formed by the radio frequency signal transmitted through the phase shifter. Figure 1 In the illustrated embodiment, the shiftable transmission mechanism 10 includes 14 parallel-arranged transmission rods 101. However, this disclosure is not limited to this. The number of transmission rods 101 can be increased or decreased according to actual needs.

[0055] like Figure 2 As shown more clearly, the shiftable transmission mechanism 10 may include a transmission unit 20 and a shifting unit 30. The transmission unit 20 is configured to be driveably connected to one of the plurality of transmission rods 101 to drive that rod to rotate. The shifting unit 30 is configured to move at least a portion of the transmission unit 20 so that the transmission unit 20 can be driveably connected to any one of the transmission rods 101. The transmission unit 20 and the shifting unit 30 may be mounted in a frame 40. The frame 40 may include a bottom wall and a first side wall 401 extending upward from the bottom wall, a second side wall 402 opposite to the first side wall, a first end wall 403, and a second end wall 404 opposite to the first end wall. The transmission unit 20 and the shifting unit 30 may be spaced apart from the transmission rods 101 by the second side wall 402.

[0056] Reference Figures 3 to 4The diagram illustrates the specific structure of a transmission unit 20 according to an embodiment of the present disclosure. The transmission unit 20 may include a first gear assembly consisting of a first gear 201 and a second gear 202 meshing with each other, and a second gear assembly consisting of a third gear 203 and a fourth gear 204 meshing with each other. The first gear assembly may be fixed to a corresponding wall of the frame 40, while the second gear assembly may move laterally in a direction perpendicular to the axial direction of the transmission rod 101 to drive through any of the transmission rods 101 at different positions. This configuration allows the transmission unit 20 of the present disclosure to drive through any of the plurality of transmission rods 101 using only the laterally movable second gear assembly, thereby greatly reducing the number of components in the transmission unit 20 and simplifying its structure.

[0057] In embodiments according to this disclosure, the first gear 201 and the second gear 202 are rotatably fixed to the first sidewall 401 of the frame 40 and the first endwall 403 perpendicularly adjacent to the first sidewall 401, respectively, at substantially the same height or plane, such that the central axis of the first gear 201 is arranged substantially perpendicular to the central axis of the second gear 202. The third gear 203 is drive-connected to the second gear 202 via a laterally extending drive shaft 205. The drive shaft 205 has a non-circular outer circumferential shape, allowing the third gear 203 to translate laterally along the drive shaft 205 but not to rotate relative to it. The fourth gear 204 is arranged at substantially the same height or plane as the third gear 203. The central axis of the fourth gear 204 is arranged substantially perpendicular to the central axis of the third gear 203, and the central axis of the fourth gear 204 is parallel to the axial direction of the drive rod 101, facilitating drive-connection of the fourth gear 204 to either drive rod 101. This configuration not only allows the first gear 201, second gear 202, third gear 203, and fourth gear 204 to be at substantially the same height or plane, but also enables them to be more compact, thereby significantly reducing the space occupied by the transmission unit 20. In embodiments according to this disclosure, the first gear 201, second gear 202, third gear 203, and fourth gear 204 are configured as bevel gears or include bevel gear portions.

[0058] The first gear 201 can be driven to a first motor (not shown) via a motor adapter 206. The fourth gear 204 can be driven to any one of the drive rods 101 via a rod adapter 207. The rod adapter 207 is configured to move along the axial direction of the drive rod 101 between an engaged position and a disengaged position, in which the rod adapter 207 is engaged with the drive rod 101 and in the disengaged position, the rod adapter 207 is disengaged from the drive rod 101. Specifically, as Figure 3As shown, one end of the fourth gear 204 is provided with a shaft 208 that mates with the rod adapter 207. The shaft 208 can be inserted into the axial cavity of the rod adapter 207. The shaft 208 of the fourth gear 204 and the axial cavity of the rod adapter 207 have matching non-circular shapes, allowing the rod adapter 207 to translate along the shaft 208 between an engaged position and a disengaged position, but not to rotate relative to the shaft 208.

[0059] When the lever adapter 207 is engaged with any of the drive rods 101, the operation of adjusting the phase shifter can be performed. During the operation of driving the phase shifter, the first motor drives the first gear 201 via the motor adapter 206, the first gear 201 drives the second gear 202 meshing with it, the second gear 202 drives the third gear 203 via the drive shaft 205, the third gear 203 drives the fourth gear 204 meshing with it, and the fourth gear 204 then drives any of the drive rods 101 connected to it via the lever adapter 207.

[0060] When the lever adapter 207 disengages from the drive lever 101, a gear shifting operation can be performed. During the gear shifting operation, the third gear 203, the fourth gear 204, and the lever adapter 207 can move laterally to selectively engage any one of the drive levers 101. To enable the third gear 203 and the fourth gear 204 to move synchronously laterally, they can be rotatably held in the gear holder 209. Figure 5 As shown, the gear retainer 209 may include an upper half 210 and a lower half 211 that are separable from each other. Both the upper half 210 and the lower half 211 are provided with a semi-circular groove 212 for receiving the rotating shaft of the third gear 203 and a semi-circular groove 213 for receiving the rotating shaft of the fourth gear 204. The upper half 210 and the lower half 211 can be connected together by screws to rotatably hold the third gear 203 and the fourth gear 204 in the grooves 212 and 213, respectively. The top of the upper half 210 is provided with lateral holes 216 and 217 through which guide rods 214 and 215 extend, respectively. The guide rods 214 and 215 are used to guide the lateral movement of the gear retainer 209.

[0061] Additionally, the rod adapter 207 can be rotatably clamped in the rod adapter retainer 218, so as to move axially between an engaged position and a disengaged position and laterally under the action of the rod adapter retainer 218. Figure 6As shown, the rod adapter holder 218 may include an upper half 219 and a lower half 220 that are separable from each other. Both the upper half 219 and the lower half 220 are provided with a semi-circular groove 221 for receiving the rod adapter 207. An annular protrusion 222 is provided on the inner surface of the semi-circular groove 221, which engages with an annular groove 223 provided in the rod adapter 207 to limit axial movement of the rod adapter 207 relative to the rod adapter holder 218. The upper half 219 and the lower half 220 can be connected together by screws to rotatably clamp the rod adapter 207 in the semi-circular groove 221. The top of the upper half 219 is provided with a transverse hole 225 through which the guide rod 224 extends and a transverse threaded hole 227 through which the screw 226 extends. When the screw 226 rotates, the rod adapter retainer 218 can move laterally along the screw 226, thereby causing the rod adapter 207, the gear retainer 209, and the third gear 203 and the fourth gear 204 held in the gear retainer 209 to move laterally together.

[0062] In embodiments according to this disclosure, both axial and lateral movement of the rod adapter retainer 218 are achieved via the shifting unit 30. Next, reference will be made to... Figures 7 to 9 The specific structure of the shift unit 30 is described below. The shift unit 30 may include an axial drive assembly 301 and a lateral drive assembly 302. The axial drive assembly 301 is configured to move the lever adapter 207 between an engaged position and a disengaged position along the axial direction, while the lateral drive assembly 302 is configured to laterally move the lever adapter 207 and the second gear assembly consisting of a third gear 203 and a fourth gear 204 when the lever adapter 207 is disengaged from the drive rod 101.

[0063] like Figure 7 and Figure 8 As shown, the axial drive assembly 301 includes an axially movable sliding plate 303 and a drive shaft 304 for axially moving the sliding plate 303. The drive shaft 304 can be configured as a screw. One end of the drive shaft 304 is threadedly connected to the end face 305 of the sliding plate 303 to cause axial movement of the sliding plate 303 when the drive shaft 304 rotates. The other end of the drive shaft 304 is provided with a spur gear 306, which meshes with a spur gear 308 mounted on the end of a motor adapter 307. The motor adapter 307 is driven by a second motor (not shown), which drives the spur gear 306 of the drive shaft 304 through the spur gear 308 of the motor adapter 307, thereby rotating the drive shaft 304 and causing axial movement of the sliding plate 303. The gear ratio of the spur gears 308 and 306 can be selected to obtain the desired axial movement speed of the sliding plate 303.

[0064] The sliding plate 303 is configured to drive the rod adapter retainer 218 mounted thereon to move axially together with it, thereby allowing the rod adapter 207 to move axially between an engaged position and a disengaged position. For this purpose, the sliding plate 303 is provided with two spaced-apart, laterally extending grooves 309. Figure 9 One of the grooves 309 is clearly shown; correspondingly, the bottom of the lower half 220 of the rod adapter holder 218 is provided with two laterally extending protrusions 228, each of which can be received in a corresponding groove 309. Thus, the rod adapter holder 218 can move axially with the sliding plate 303 by means of the engagement of the protrusions 228 and the grooves 309, and can also move laterally on the sliding plate 303. Furthermore, for smoother axial movement of the sliding plate 303, both ends of the sliding plate 303 can be respectively mounted on two axially extending guide rods (not shown). Each guide rod can extend through a guide hole 310 provided at either end of the sliding plate 303, and both ends of each guide rod can be fixed to the first sidewall 401 and the second sidewall 402 of the frame 40.

[0065] When the axial drive assembly 301 moves the rod adapter 207 to the disengaged position, the rod adapter 207 and the second gear assembly consisting of the third gear 203 and the fourth gear 204 are moved laterally via the lateral drive assembly 302. Figure 9 The specific structure of the lateral drive assembly is shown. In an embodiment according to this disclosure, the lateral drive assembly includes a fifth gear 311 and a sixth gear 312. The fifth gear 311 is configured to be rotatably fixed to a first end wall 403 of the frame 40, while the sixth gear 312 is configured to be rotatably fixed to an end wall of a sliding plate 303, to move axially between an engaged position and a disengaged position in response to axial movement of the sliding plate 303. In the engaged position, the rod adapter 207 disengages from the drive rod 101, and the sixth gear 312 engages with the fifth gear 311 and can rotate under the drive of the fifth gear 311; in the disengaged position, the rod adapter 207 engages with the drive rod 101, and the sixth gear 312 is separated from the fifth gear 311. The sixth gear 312 may be fixedly connected to the screw 226 or integrally formed as one end of the screw 226. Thus, when the sixth gear 312 rotates, it will drive the screw 226 to rotate. The rotation of the screw 226 causes the rod adapter retainer 218 to move laterally along the screw 226, thereby driving the rod adapter 207, the gear retainer 209, and the third gear 203 and the fourth gear 204 held in the gear retainer 209 to move laterally together.

[0066] In embodiments according to this disclosure, the fifth gear 311 and the sixth gear 312 can be configured as spur gears. To reduce the number of drive units and other components, the lateral drive assembly 302 is configured to be driven by a first motor via the first gear assembly. Specifically, the fifth gear 311 is configured to be driveably connected to the second gear 202 of the first gear assembly. For this purpose, the second gear 202 includes, in addition to the bevel gear portion 2021 meshing with the first gear 201, a spur gear portion 2022 meshing with the fifth gear 311. During gear shifting, the first motor drives the first gear 201, which in turn drives the second gear 202 via its bevel gear portion 2021. The second gear 202 then drives the fifth gear 311 via its spur gear portion 2022, and the fifth gear 311 in turn drives the sixth gear 312. This configuration avoids additional drive units and transmission components and simplifies the overall structure of the transmission mechanism.

[0067] In embodiments according to this disclosure, the bevel gear portion 2021 and the spur gear portion 2022 of the second gear 202 can be integrally formed or constructed as two separate components fixedly connected to each other. In embodiments according to this disclosure, except for the guide rod which is made of metal, all other components (e.g., the first gear 201, second gear 202, third gear 203, fourth gear 204, fifth gear 311, sixth gear 312, gear retainer 209, rod adapter retainer 218, screw 226, drive shafts 205 and 304, etc.) can be made of plastic materials (e.g., POM or PBT). This not only reduces the weight of the shiftable transmission mechanism 10 but also saves on the cost of the shiftable transmission mechanism 10. Furthermore, since the screw 226 can be made of plastic, it can be manufactured as a non-standard part. This allows the pitch of the screw 226 to be selected as needed, thereby enabling the selection of the desired speed of lateral movement of the lever adapter retainer 218 and the lever adapter 207 for more precise gear shifting.

[0068] The shiftable transmission mechanism 10 according to this disclosure may further include a locking mechanism 50 for the transmission rod 101. The locking mechanism 50 is configured to prevent rotation of the transmission rod 101 when the rod adapter 207 is disengaged from the transmission rod 101, thereby avoiding changes to the phase shifter settings. (See also...) Figures 10 to 12The specific structure of the locking mechanism 50 is shown. The locking mechanism 50 includes a bushing 501 mounted on one end of each drive rod 101. Each bushing 501 is configured to be non-rotatable relative to the drive rod 101. One end of the bushing 501 is provided with a flange 502, and the side of the flange 502 is provided with a plurality of keys 503 distributed along the circumferential direction of the flange 502 and extending along the axial direction of the bushing 501. The keys 503 can engage with keyways (not shown) provided in the second sidewall 402 of the frame 40 to lock the bushing 501 and prevent the bushing 501 and the drive rod 101 from rotating. The end of the bushing 501 with the flange 502 is also provided with a non-circular inner cavity 504 into which the end of the drive rod 101 can be inserted. The inner cavity 504 extends through a portion of the bushing 501 in the axial direction. An elastic member (such as a spring 505) is provided in the inner cavity 504, and the spring 505 can push the bushing 501 in the axial direction. The other end of the bushing 501 can extend through the second sidewall 402 of the frame 40 and be inserted into the inner cavity 504 of the rod adapter 207. The outer surface of the other end of the bushing 501 is provided with a plurality of keyways 506 distributed circumferentially. The keyways 506 can engage with a key 229 provided in the inner cavity of the rod adapter 207 to prevent the bushing 501 from rotating relative to the rod adapter 207. An annular protrusion 230 is also provided in the inner cavity of the rod adapter 207 to limit the depth to which the bushing 501 is inserted into the inner cavity of the rod adapter 207.

[0069] When the bushing 501 disengages from the rod adapter 207, the spring 505 pushes the bushing 501 along the direction that brings the flange 502 of the bushing 501 closer to the second side wall 402 of the frame 40, causing the key 53 of the bushing 501 to enter the keyway of the second side wall 402, thereby locking the bushing 501 and the transmission rod 101 and preventing them from rotating (e.g. Figure 11 (As shown). When the bushing 501 engages with the rod adapter 207, the annular protrusion 230 of the rod adapter 207 abuts against the end of the bushing 501 that is inserted into the inner cavity of the rod adapter 207, and pushes the bushing 501 in a direction that moves the flange 502 of the bushing 501 away from the second side wall 402 of the frame 40, so that the key 503 of the bushing 501 comes out from the keyway of the second side wall 402, thereby unlocking the bushing 501 and the transmission rod 101 so that they can rotate (as shown). Figure 12 (As shown). The locking mechanism 50 can automatically lock the drive rod 101 so that it cannot rotate when the drive rod 101 is disengaged from the rod adapter 207, thereby preventing the phase shifter settings from being changed. This is particularly advantageous during the transportation or installation of base station antennas.

[0070] Exemplary embodiments according to this disclosure have been described above with reference to the accompanying drawings. However, those skilled in the art will understand that various changes and modifications can be made to the exemplary embodiments of this disclosure without departing from the spirit and scope of this disclosure. All changes and modifications are included within the scope of protection of this disclosure as defined by the claims. This disclosure is defined by the appended claims, and equivalents of those claims are also included.

Claims

1. A shiftable transmission mechanism for a base station antenna, characterized in that, The shiftable transmission mechanism includes: Multiple axially drivable components, wherein each axially drivable component is mounted on a corresponding one of a plurality of parallelly arranged transmission rods and is configured to be connected to a corresponding one of a plurality of phase shifters in the base station antenna; A transmission unit, comprising a first gear assembly and a second gear assembly pulverically connected to the first gear assembly, wherein the second gear assembly is capable of engaging or disengaging with any one of the plurality of transmission rods via a rod adapter movable between an engaged position and a disengaged position along the axial direction of a respective transmission rod; and A shifting unit is configured to move the second gear assembly in a lateral direction perpendicular to the axial direction when the second gear assembly disengages from any one of the plurality of drive rods, so that the shiftable transmission mechanism can selectively drive any one of the plurality of drive rods.

2. The shiftable transmission mechanism for a base station antenna according to claim 1, characterized in that, The first gear assembly and the second gear assembly are arranged at substantially the same height.

3. The shiftable transmission mechanism for a base station antenna according to claim 1, characterized in that, The first gear assembly includes a first gear and a second gear meshing with each other, and the second gear assembly includes a third gear and a fourth gear meshing with each other, wherein the third gear is connected to the second gear via a drive shaft extending along the lateral direction, the drive shaft having a non-circular outer circumferential shape.

4. The shiftable transmission mechanism for a base station antenna according to claim 3, characterized in that, The central axis of the first gear is perpendicular to the central axis of the second gear.

5. The shiftable transmission mechanism for a base station antenna according to claim 4, characterized in that, The first gear is a bevel gear, and the second gear includes a bevel gear portion that meshes with the first gear.

6. The shiftable transmission mechanism for a base station antenna according to claim 3, characterized in that, The central axis of the third gear is perpendicular to the central axis of the fourth gear.

7. The shiftable transmission mechanism for a base station antenna according to claim 6, characterized in that, Both the third gear and the fourth gear are bevel gears.

8. The shiftable transmission mechanism for a base station antenna according to claim 7, characterized in that, The third gear and the fourth gear are rotatably held in a gear holder, such that the third gear and the fourth gear can move laterally in response to lateral movement of the gear holder.

9. The shiftable transmission mechanism for a base station antenna according to claim 8, characterized in that, The gear retainer is made of plastic and includes an upper body and a lower body.

10. The shiftable transmission mechanism for a base station antenna according to claim 8, characterized in that, The shiftable transmission mechanism includes a guide rod for guiding the lateral movement of the gear retainer.

11. The shiftable transmission mechanism for a base station antenna according to claim 3, characterized in that, The first gear is configured to be driven by a first motor.

12. The shiftable transmission mechanism for a base station antenna according to claim 3, characterized in that, The fourth gear is configured to engage or disengage with any one of the plurality of drive rods via the rod adapter.

13. The shiftable transmission mechanism for a base station antenna according to claim 12, characterized in that, The rod adapter is rotatably clamped in the rod adapter holder, such that the rod adapter can move axially between the engaged position and the disengaged position in response to axial movement of the rod adapter holder, and can move laterally in response to lateral movement of the rod adapter holder.

14. The shiftable transmission mechanism for a base station antenna according to claim 13, characterized in that, The rod adapter retainer is made of plastic and includes an upper body and a lower body.

15. The shiftable transmission mechanism for a base station antenna according to claim 13, characterized in that, The shiftable transmission mechanism includes a screw for driving the lever adapter retainer to move the lever adapter retainer laterally.

16. The shiftable transmission mechanism for a base station antenna according to claim 15, characterized in that, The shiftable transmission mechanism also includes a guide rod for guiding the lateral movement of the lever adapter retainer.

17. The shiftable transmission mechanism for a base station antenna according to claim 13, characterized in that, The shifting unit includes an axial drive assembly and a lateral drive assembly, wherein the axial drive assembly is configured to move the lever adapter along an axial direction between the engaged position and the disengaged position, and the lateral drive assembly is configured to drive the second gear assembly along the lateral direction when the lever adapter is disengaged from any one of the plurality of drive rods.

18. The shiftable transmission mechanism for a base station antenna according to claim 17, characterized in that, The lateral drive assembly includes an axially movable slide plate and a drive shaft for axially moving the slide plate, the slide plate being configured such that the rod adapter moves axially between the engaged and disengaged positions when the slide plate moves axially.

19. The shiftable transmission mechanism for a base station antenna according to claim 18, characterized in that, The drive shaft is configured to be driven by a second motor.

20. The shiftable transmission mechanism for a base station antenna according to claim 19, characterized in that, One end of the drive shaft is threaded to the end face of the sliding plate to move the sliding plate axially when the drive shaft rotates. The other end of the drive shaft is provided with a spur gear, which meshes with another spur gear installed at the end of the motor adapter so that the second motor drives the drive shaft via the motor adapter.

21. The shiftable transmission mechanism for a base station antenna according to claim 17, characterized in that, The lateral drive assembly includes a third gear assembly configured to laterally move the rod adapter via the rod adapter retainer by rotating a drive screw.

22. The shiftable transmission mechanism for a base station antenna according to claim 21, characterized in that, The third gear assembly is configured to be drive-connected to the first gear assembly, such that the third gear assembly and the first gear assembly are driven by the same drive device.

23. The shiftable transmission mechanism for a base station antenna according to claim 21, characterized in that, The third gear assembly includes a fifth gear and a sixth gear, wherein the fifth gear and the sixth gear are engaged with each other when the rod adapter is disengaged from any one of the plurality of transmission rods, and the fifth gear and the sixth gear are disengaged from each other when the rod adapter is engaged with any one of the plurality of transmission rods.

24. The shiftable transmission mechanism for a base station antenna according to claim 23, characterized in that, Both the fifth and sixth gears are spur gears.

25. The shiftable transmission mechanism for a base station antenna according to claim 21, characterized in that, The pitch of the screw can be selected to obtain the desired lateral movement speed of the rod adapter.

26. The shiftable transmission mechanism for a base station antenna according to claim 3, characterized in that, The first gear, the second gear, the third gear, the fourth gear, and the drive shaft are all made of plastic.

27. The shiftable transmission mechanism for a base station antenna according to claim 23, characterized in that, The fifth gear, the sixth gear, and the screw are all made of plastic.

28. The shiftable transmission mechanism for a base station antenna according to claim 1, characterized in that, The shiftable transmission mechanism includes a locking mechanism configured to prevent rotation of the corresponding transmission rod when the rod adapter is disengaged from any of the plurality of transmission rods, so as to avoid changing the phase angle of the phase shifter.

29. The shiftable transmission mechanism for a base station antenna according to claim 28, characterized in that, The locking mechanism includes a bushing installed at one end of each transmission rod, wherein each bushing includes a flange, and the side of the flange of the bushing is provided with a plurality of keys distributed along the circumferential direction of the flange and extending along the axial direction of the bushing, the keys being configured to cooperate with keyways provided on the frame of the shiftable transmission mechanism to achieve locking.

30. The shiftable transmission mechanism for a base station antenna according to claim 29, characterized in that, The locking mechanism includes an elastic member that, when the rod adapter disengages from the corresponding transmission rod, automatically pushes the bushing along the axial direction to the position where the key mates with the keyway.

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