Technical Field

The invention relates to an antenna comprising at least two phase shifters, a main shaft and at least two coupling assemblies for coupling the main shaft with at least one of the phase shifters.

Background

Antennas having a plurality of phase shifters driven by a single electric motor are known. In order to selectively actuate the phase shifters, it is known to use multi clutches or gearboxes. Multi clutches and gearboxes are known, for example from US 10 581 163 B2, and usually have a driven main shaft and a plurality of output shafts connected to the phase shifters. The main shaft is located in the center and the output shafts are arranged around the main shaft along its periphery. The main shaft is selectively coupled to one of the output shaft using movable gear wheels actuated by a coupling actuator.

These types of multi clutches and gearboxes are limited with respect to the number of phase shifters that can be addressed while maintaining a compact design. Further, the positions of the output shafts cannot be chosen freely as they are given by the position of the main shaft.

Summary

It is therefore an object of the invention to provide an antenna with a plurality of phase shifters having a coupling assembly that is compact and simple in design even for a larger number of phase shifters.

For this purpose, an antenna is provided, in particular a mobile communication antenna, the antenna comprising at least two phase shifters; a main shaft; and at least two coupling assemblies, each associated with one of the at least two phase shifters to selectively couple the main shaft with the associated one of the phase shifters. Each coupling assembly comprises an input shaft coupled to the main shaft; an output shaft coupled to the associated phase shifter, and an engagement member movable between an engaged position and a disengaged position in an axial direction with respect to the common axis. The input shaft and the output shaft are arranged concentrically on a common axis, and an end face of the input shaft and an end face of the output shaft are facing each other. In the disengaged position, the engagement member is disengaged from one or both of the input shaft and the output shaft, and in the engaged position, the engagement member engages both the input shaft and the output shaft.

It is of course possible that the input shaft is part of the main shaft, e.g. that the last coupling assembly is driven directly by the main shaft meaning that the end portion of the main shaft is the input shaft in this case.

The coaxial arrangement of the input shaft and the output shaft of the coupling assembly leads to a simple and compact design as no hollow shafts or quill shafts are needed. Further, by separating the coupling assemblies for each of the phase shifters from one another, the position of the output shafts can be chosen freely along the main shaft. As such, the output shafts may be coupled directly to the associated phase shifters, e.g. without further gears, and/or in a straight line. This way, the number of components as well as friction and wear of the system are reduced drastically.

The engagement of the engagement member with the input shaft and the output shaft simultaneously allows torque transmission from the input shaft to the output shaft and thus from the main shaft to the respective phase shifter.

The antenna is, for example, a mobile communication antenna and may comprise at least two radio frequency radiators each one connected to one of the phase shifters.

The input shaft may be coupled to the main shaft via bevel gears and/or friction gears.

The engagement between the engagement member and the input shaft and/or the output shaft, in particular between the end faces that are to be coupled, may be realized by friction or by positive locking.

In an embodiment, the coupling assembly is free from gear wheels so that a simple and compact design is achieved.

In an aspect, the antenna comprises a memory configured to store the rotational position of the engagement member, the input shaft and/or the output shaft of each coupling assembly at the time of disengagement. Using the stored rotational position, before the input shaft and/or the output shaft are engaged with the engagement member anew, the respective shaft can be rotated to assume the rotational position it had at the time of disengagement - or an equivalent thereto due to symmetry. This way, errors in the actuation of the phase shifters, in particular errors that would add up over the lifetime of the antenna, are reduced.

In another embodiment, the antenna comprises a main actuator, in particular an electric motor, connected to the main shaft and a control unit for controlling the actuator, in particular wherein the control unit is configured to obtain the rotational position of the main actuator and to store the rotational position in the memory. The rotational position of the engagement member, the input shaft and/or the output shaft may be determined using the obtained rotational position of the main actuator, thus simplifying the control unit.

The memory may be part of the control unit or separate from the control unit.

In an aspect of the invention, the engagement member comprises an input portion and an output portion on opposite ends of the engagement member, wherein the input portion is configured to engage the input shaft and the output portion is configured to engage the output shaft. As such, the engagement member is individually fitted to the input and output shaft.

The input shaft and/or the output shaft has a coupling portion extending from the end face, the coupling portion having a non-circular outer and/or a non circular inner contour, and wherein the input portion and/or the output portion of the engagement member has a shape complementary to the respective non circular outer and/or the non-circular inner contour of the respective shaft. By choosing complementary contours, the engagement member and the respective shaft are interlocking efficiently. The contour is to be understood as the contour of the respective cross-section and the end face is regarded as part of coupling portion.

In cases of inner contours, the contour defines a recess in the coupling portion and/or the engagement member. For example, the complementary shape to a cross-shaped outer contour in one of the shafts is a recess with a cross-shaped contour in the respective portion of the engagement member.

For an even simpler and more compact design, the engagement member may be concentric with the input shaft and the output shaft and/or movable relative to the input shaft and the output shaft.

In an aspect of the invention, the coupling assembly comprises a hull which at least partially surrounds the engagement member and is movable in the axial direction, wherein the engagement member is arranged rotatably in the hull. The non-rotating hull allows the rotation of the engagement member in the hull. By the use of the hull, which does not rotate, the hull and with that the engagement member within the hull may be actuated using a stationary, i.e. non-rotating, actuation member, which drastically simplifies the construction.

For example, the engagement member is movable together with the hull in the axial direction. The input shaft and the output shaft may extend through the hull. In order to reduce the complexity of the actuation assembly, the coupling assembly may comprise a restoring member configured to apply a restoring force to the engagement member towards the disengaged position, in particular wherein the restoring member is attached to the hull and/or comprises a spring. In particular, the restoring member is attached to the hull with one end and to a stationary part of antenna with another end.

In another embodiment of the invention, the antenna comprises an actuation assembly configured to move the engagement member of one or more of the coupling assemblies from the disengaged position into the engaged position. With the actuation assembly, the phase shifter to be actuated can be selected individually.

In an aspect, the actuation assembly comprises an actuation member adapted to urge the engagement member in the engaged position, particularly wherein the actuation member engages with an actuation portion of the hull and/or the engagement member. This way, a simple actuation of the engagement member is realized. For example, the actuation portion may be a protrusion.

In particular, the engagement member is biased against the restoring force of the restoring member.

In one embodiment of the invention, the actuation assembly comprises a carrier, wherein at least one actuation member is attached to the carrier, in particular wherein the at least one actuation member is adapted to actuate more than one of the coupling assemblies. Using a carrier allows to use a single actuation assembly for multiple coupling assemblies and thus reduces the number of components.

In order to control the actuation assembly precisely, the actuation assembly comprises a coupling actuator, in particular an electric motor, configured to actuate the carrier. To assure a reliable actuation of the coupling assembly, the at least one actuation member is a cam or the at least one actuation member is a lever, in particular a lever pivotably mounted to the carrier and movable between an active position and an inactive position.

The lever may be fixed in the active position by a locking mechanism and/or held in the active position by an elastic element, e.g. a spring.

A simple and reliable antenna is realized, if the carrier is a tape drive or a rigid elongated member, in particular a rack.

In another embodiment of the invention, the actuation assembly comprises at least one electromagnet and at least one magnetic element, in particular a permanent magnet and/or a ferromagnet, wherein the at least one magnetic element is arranged in and/or on the engagement member, particularly wherein the at least one electromagnet is at least one solenoid and the engagement member is arranged partially within the at least one solenoid. Using magnetic forces to actuate the coupling assemblies reduces the number of mechanical components of the actuation assembly.

A permanent magnet may also be a cascade of a plurality of smaller permanent magnets.

To reduce the time that the at least one electromagnet has to be energized, the coupling assembly may comprise a locking mechanism for locking the engagement member in the disengaged position and/or the engaged position, in particular wherein the locking mechanism comprises a spring-loaded ball and at least one, in particular two grooves. For example, the grooves in the engagement member extend along the full periphery of the engagement member and/or the spring of the spring-loaded ball is mounted to a stationary part of the antenna. In a further embodiment, two electromagnets are provided in the coupling assembly, in particular the two electromagnets are independently controllable from each other. This way, the electromagnets may be smaller.

In an aspect of the invention, the at least one magnetic element is arranged in and/or on the engagement member such that the at least one magnetic element lies asymmetrically with respect to a transverse plane spanning in the middle between the axially most distant ends of the at least one electromagnet when the at least one electromagnet is energized and/or in the disengaged position as well as the engaged position of the engagement member. Due to the asymmetric arrangement, situations in which the engagement member is in an indifferent and unstable position are avoided.

The transverse plane is to be understood as a plane transverse and perpen dicular to the common axis.

Brief Description of the Drawings

Further features and advantages will be apparent from the following description as well as the accompanying drawings, to which reference is made. The drawings show in detail:

Fig. 1: a very schematic drawing of an antenna according to the invention;

Fig. 2: a coupling section of the antenna according to Figure 1 schematically; Figs. 3, 4: schematically a coupling assembly of the coupling section according to a first embodiment of the invention in a disengaged and an engaged position, respectively;

Fig. 5: schematically a top view of the end faces of the engagement member and of a shaft of the coupling assembly according to

Figures 3 and 4;

Figs. 6a, 6b: schematically the coupling section of Figure 2 with the coupling assembly of Figures 3 and 4 in two different positions during operation; Fig. 7: schematically a coupling section according to a second embodiment of the invention;

Figs. 8a, 8b: schematically an actuation assembly of a coupling section according to a third embodiment of the invention in two different positions; Figs. 9a, 9b: schematically the coupling section with the actuation assembly of Figures 8a and 8b in two different positions during operation;

Fig. 10: schematically an actuation assembly according to a fourth embodiment of the invention;

Fig. 11: schematically a coupling assembly according to a fifth embodiment of the invention in an exploded view;

Figs. 12a-d: schematically the coupling assembly according to Figure 11 in four different positions during operation; and

Figs. 13a-d: schematically a coupling assembly according to a sixth embodiment of the invention in four different positions during operation.

Detailed Description

Figure 1 shows an antenna 10 very schematically. The antenna 10 is for example a mobile communication antenna used in mobile communication base stations. The antenna 10 comprises a plurality of radiators 12, which may form radiator arrays 112, a plurality of phase shifters 14, a coupling section 16, a main shaft 18, a main actuator 20, a control unit 22, a memory 24 and a coupling actuator 26.

The phase shifters 14 will control the distribution of the phase of the radiators 12 in the different radiator arrays 112. The different radiator arrays 112 of the same antenna 10 may be dual polarized arrays, which operate in different frequency bands.

The memory 24 may be part of the control unit 22 or separate from the control unit 22. In the shown example, the antenna 10 comprises five phase shifters.

The radiators 12 are for example radio frequency radiators, in particular dual polarized radiators.

Each one of the phase shifters 14 is associated with one radiator 12, meaning that the output ports of the phase shifter 14 are connected to the corresponding input ports of the associated radiator 12.

The phase shifters 14 are for example differential phase shifters 14 as known in the art, for example from US 6 850 130 Bl. Of course, the phase shifters 14 may be of any other kind, for example dielectric phase shifters.

The phase shifters 14 are driven separately, each by a separate torque transmitting shaft. The shafts are called output shafts 28 in the following as they will be explained in more detail with respect to the coupling section 16.

The torque for driving the phase shifters 14 is supplied by the main actuator 20 and fed to the phase shifters 14 via the coupling section 16. The coupling section 16 comprises a plurality of coupling assemblies 30 (Fig. 2) which are actuated by the coupling actuator 26. Each coupling section 30 is associated with one of the phase shifters 14 so that the main shaft 18 may be coupled to a specific phase shifter 14 to be actuated by actuating the associated coupling assembly 30.

The control unit 22 controls the main actuator 20 as well as the coupling actuator 26 in order to actuate the phase shifters 14 to achieve the desired beam characteristic of the plurality of radiators 12.

Figure 2 shows a first embodiment of the coupling section 16 schematically with five coupling assemblies 30 and an actuation assembly 31.

Each coupling assembly 30 is associated with one of the phase shifters 14 and comprises one of the output shafts 28 at least partly, an input shaft 32, an engagement member 34 and a hull 36 for the engagement member 34.

The main shaft 18 extends through the coupling section 16, and each input shaft 32 of each one of the coupling assemblies 30 is coupled to the main shaft 18, in particular permanently. This can be achieved, for example, via gears 38 like bevel gears and/or friction gears.

On the output end of each coupling assembly 30, the respective output shaft 28 is connected to the phase shifter 14 in particular directly, e.g. without further gears and/or in a straight line.

In the following, one of the coupling assemblies 30 and its function is described in detail in Figures 3 to 5 as an example for any one of the coupling assemblies 30. The input shaft 32 and the output shaft 28 are arranged concentrically to one another on a common axis A. In the following, terms like axial, peripheral, axial direction and the like are referring to the respective directions of the common axis A.

The end faces 40 of the input shaft 32 and of the output shaft 28 that are to be coupled - namely the end face 40 of the input shaft 32 not coupled to the main shaft 18 and the end faces 40 of the output shaft 28 not coupled to the phase shifter 14 - are facing each other. But, end face 40 of the input shaft 32 is permanently coupled via gears 38 to the main shaft

The input shaft 32 as well as the output shaft 28 each have a coupling portion 42 extending from the respective end face 40 towards the opposite end of the respective shaft.

The engagement member 34 is arranged movably in the axial direction of the common axis A in the region of the coupling portions 42.

In the shown embodiment, the engagement member 34 has an input portion 44 adapted to engage the coupling portion 42 of the input shaft 32 as well as an output portion 46 adapted to engage the coupling portion 42 of the output shaft 28. The input portion 44 and the output portion 46 are on opposite ends of the engagement member 34.

In the shown embodiment, the engagement member 34 surrounds the coupling portion 42 of the input shaft 32 and/or of the output shaft 28 in the peripheral direction at least partly, in particular fully.

To this end, the engagement member 34 has a shape complementary to that of the coupling portion 42 of the respective shaft 28, 32. More precisely, the IB shape of the input portion 44 of the engagement member 34 is designed complementary to the coupling portion 42 of the input shaft 32, and the output portion 46 of the engagement member 34 is formed complementary to the coupling portion 42 of the output shaft 28.

The coupling portions 42 of the input shaft 32 and the output shaft 28 have, for example, a cross-section with a non-circular outer contour 48. In addition or alternatively, the coupling portions 42 may have a non-circular inner contour.

In the shown embodiment and depicted in Figure 5, the coupling portion 42 of the output shaft 28 and the input shaft 32 are identical in shape, having an outer contour 48 being a rectangular. Of course, the outer contour 48 may have any other suitable shape to transmit torque, for example a cross shape or a star shape.

Consequently, the engagement member 34 has a cross-section with an inner contour 50, i.e. a recess with such a contour, being a rectangular slightly larger than the rectangular of the outer contour 48 of the coupling portion 42. The outer contour of the engagement member 34 may be circular.

In the shown embodiment, the complementary shape of the engagement member 34 is created by a rectangular channel 52 extending from the input portion 44 to the output portion 46 through the entire axial length of the engagement member 34.

The engagement member 34 is rotatably mounted in the hull 36 and the engagement member 34 and the hull 36 are arranged concentrically to the common axis A. The hull 36 surrounds the engagement member 34 at least partially in the axial direction and forms a housing for the engagement member 34.

In order for the input and output shaft 32, 28 to engage the engagement member 34, the hull 36 has openings 53 in the region of the inner contour 50 of the input and output portion 44, 46.

The engagement member 34 is axially fixed in the hull 36 but rotatably mounted with respect to the hull 36. This may be achieved by a tight fit in the axial direction and a suitable lubricant or a suitable choice of self-lubricant materials of the engagement member 34 and the hull 36 to allow for rotation.

Further, the engagement member 34 and the hull 36 are movable in the axial direction relative to the input shaft 32 and the output shaft 28.

The engagement member 34 and the hull 36 can assume a disengaged position shown in Figure 3 and an engaged position shown in Figure 4.

In the disengaged position, the coupling portion 42 of the output shaft 28 engages in the output portion 46 of the engagement member 34. To this end, the coupling portion 42 or any other portion of the output shaft 28 extends through a suitable opening in the hull 36.

The coupling portion 42 of the input shaft 32, however, is not engaged in the input portion 44 of the engagement member 34. Thus, a rotation of the input shaft 32 does not result in a rotation of the output shaft 28.

In the shown embodiment, in the disengaged position, the output shaft 28 extends through one of the openings 53 in the hull 36, wherein the other opening 53 is large enough for the input shaft 32 to rotate freely within it. In the engaged position, the engagement member 34 and the hull 36 have been moved axially towards the input shaft 32 so that the coupling portion 42 of the input shaft 32 engages with the input portion 44 of the engagement member 34.

At the same time, the coupling portion 42 of the output shaft 28 still extends into the output portion 46 of the engagement member 34. The input shaft 32 is therefore engaged in the engagement member 34 and the engagement member 34 is engaged in the output shaft 28. Thus, a rotation of the input shaft 32 leads to a rotation of the engagement member 34 and with that a rotation of the output shaft 28. The hull 36 does not rotate, neither in the disengaged position nor in the engaged position.

Further, a restoring member 54 is connected to the hull 36 with one of its ends and to a stationary part 56 of the antenna 10 with its other end. The restoring member 54 is adapted and mounted such that it applies a restoring force F towards the disengaged position to the hull 36.

In the shown embodiment, a spring is used as a restoring member 54, wherein the spring is being compressed when the hull 36 is moved in the engaged position.

The actuation of the coupling assembly 30 by the actuation assembly 31 is described in the following with reference to Figures 6a and 6b.

The actuation assembly 31 comprises a carrier 58, a drive member 60 and an actuation member 62.

In the shown embodiment, the carrier 58 is an elongated member, for example a rack, and the drive member 60 is circular gear connected to the coupling actuator 26, which may be an electric motor. Thus, the carrier 58 and the drive member 60 form a rack and pinion assembly in the shown embodiment.

The carrier 58 is arranged on the output side of the engagement member 34, e.g. between the engagement member 34 of the coupling assembly 30 and the phase shifters 14.

The carrier 58 extends parallel to the main shaft 18 and in particular along all of the coupling assemblies 30 so that only one actuation assembly 31 for all of the coupling assembly 30 is needed.

The carrier 58 can be driven by the drive member 60 in the longitudinal direction of the carrier 58 and thus in a direction transverse to the common axis A.

Of course, it is also possible that the actuation assembly 31 may only actuate fewer coupling assemblies 30 or only a single one.

The actuation member 62 is provided on the carrier 58 on the side facing the coupling assemblies 30. In the shown embodiment, the actuation member 62 is a cam 64 extending towards the coupling assembly 30 in the axial direction.

The cam 64 has an end face 68 parallel to the carrier 58 and transverse to the axial direction and angled side faces 69 extending from the end face 68 towards the carrier 58.

The hull 36, and in other embodiments possibly the engagement member 34, comprises an actuation portion 66 at a position facing the carrier 58. In the shown embodiment, the actuation portion 66 is a protrusion extending towards the carrier 58 from the axial end face of the hull 36. Actuation of one of the coupling assemblies 30 may be achieved by driving the carrier 58 such that the cam 64 engages with the actuation portion 66 of the coupling assembly 30 to be actuated.

In the situation shown in Figure 6a, all coupling assemblies 30 are in the disengaged position. In Figure 6b, the coupling assembly 30 on the right-hand side is in the engaged position and the remaining coupling assemblies 30 are in the disengaged position.

For example, in the situation shown in Figure 6a, the coupling assembly 30 on the right-hand side is actuated by moving the carrier 58 to the right. To this end, the control unit 22 controls the coupling actuator 26 to drive the drive member 60, which in turn moves the carrier 58.

By moving the carrier 58, the cam 64 moves to the right simultaneously and the side face 69 of the cam 64 comes in contact with the actuation portion 66.

Due to the angle of the side face 69, the actuation portion 66 and with that the hull 36 and the engagement member 34 are urged axially against the restoring force F applied by the restoring member 54.

The axial movement continues until the end faces 68 comes in contact with the top of the actuation portion 66. In this state, shown in Figure 6b, the hull 36 and engagement member 34 have been moved fully towards the input shaft 32 and are now in the engaged position.

The input shaft 32 and the output shaft 28 and with that the main shaft 18 and the associated phase shifter 14 are now coupled. The phase shifter 14 may now be actuated by powering the main actuator 20 to rotate the main shaft 18. In order to decouple the input shaft 32 and the engagement member 34, the carrier 58 and the cam 64 are moved laterally. In doing so, the cam 64 does no longer engage the actuation portion 66 so that the hull 36 and the engagement member 34 are moved into the disengaged position by the restoring force F of the restoring member 54.

Before the engagement member 34 can be brought from the disengaged position into the engaged position, the corresponding input shaft 32 has to assume a rotational position in which the contour of the coupling portion 42 of the input shaft 32 is in alignment with the contour of the input portion 44 of the engagement member 34.

The alignment is lost if the main shaft 18 is rotated at times when the engagement member 34 of the respective coupling assembly 30 is in the disengaged position, for example if another phase shifter 14 is actuated via another coupling assembly 30.

In order to guarantee alignment, the control unit 22 stores for each one of the input shafts 32 the rotational position of the respective input shaft 32 at the time of disengagement separately in the memory 24. The rotational position of the respective input shaft 32 may be determined by the rotational position of the main actuator 20.

When the engagement of a specific coupling assembly 30 is desired, the control unit 22 aligns the rotational positions of the input shaft 32 and the engagement member 34.

Using the stored rotational position of the input shaft 32, the control unit 22 actuates the main actuator 20 to rotate the respective input shaft 32 before the hull 36 is engaged by the actuation assembly 31. The input shaft 32 is rotated until it assumes the stored rotational position or a position equivalent thereto.

Equivalent positions that also allow engagement are, for example, positions arising from the symmetry of the contour of the coupling portion 42 of the input shaft 32.

Once the stored or an equivalent position has been assumed, the control unit 22 drives the coupling actuator 26 so that the engagement member 34 is urged into the engaged position.

In order to engage another one of the coupling assemblies 30, the carrier 58 is moved to a different position so that the cam 64 engages with the actuation portion 66 of the hull 36 of another one of the coupling assemblies 30.

Thus, the phase shifters 14 of the antenna 10 can be actuated selectively without a complex and large multi-gear assembly. At the same time, the coupling assemblies 30 are free of gears rendering them simple and cost- efficient. Further, the number of phase shifters 14 that can be actuated via the main actuator 20 is not limited by the coupling assemblies or any gear set. Further, the coupling assemblies 30 can be placed freely so that it is possible to couple the phase shifters 14 directly to the coupling assemblies 30. This way, the number of components is kept low as no additional gears or universal joints are needed.

Even though the function has been described with the engagement member 34 being permanently engaged with the output shaft 28 and selectively engageable with the input shaft 32, it is of course possible that the engagement member 34 is permanently engaged with the input shaft 32 and selectively engageable with the output shaft 28. In this case, the rotational position of the engagement member 34 with respect to the output shaft 28 is stored in the memory 24.

In the following, further embodiments of the invention are shown which essentially correspond to the embodiment described in Figures 1 to 6 so that only the differences are discussed in following. The same and functionally the same components are labeled with the same reference signs.

Figure 7 shows a second embodiment of the coupling section 16 of the invention. In the embodiment according to Figure 7, the actuation assembly 31 is not a rack and pinion drive but a belt drive. The carrier 58 is a belt, to which the cam 64 is attached to on the outside. The drive member 60 drives the belt.

A third embodiment of the invention is shown in Figures 8 and 9. Figures 8a and 8b show the actuation assembly 31 schematically in different situations.

In this embodiment, the actuation member 62 of the actuation assembly 31 is a lever 70. In the example shown in the drawings, the carrier 58 comprises two levers 70.

The lever 70 is pivotably attached to the carrier 58 and has an actuation end 71 for engagement with the actuation portion 66 of the hull 36. The actuation end 71 is spaced apart from the pivot, for example the actuation end 71 is the end opposite to the pivot.

Further, for each lever 70, an elastic element 72, e.g. a spring, and a locking mechanism are provided. The locking mechanism has a first part 74 mounted to the lever 70 and a second part 76 mounted to the carrier 58. The second part 76 is movable with respect to the carrier 58 and biased by the elastic element 72. Each lever 70 may assume an active position shown on the right-hand side of Figure 8a and an inactive position shown on the left-hand side of Figure 8a.

In the inactive position, the lever 70 is locked by the locking mechanism, in particular the lever 70 is parallel to the carrier 58 in the inactive position.

In the active position, the lever 70 pivotable but biased by the elastic element 72 so that the actuation end 71 is pivoted towards the coupling assemblies 30 - downwards in the drawings - compared to the inactive position.

In the active position, the levers 70 are in particular not vertical or perpendicular to the carrier 58 but the actuation ends 71 are lifted by the force of the elastic element 72. For example, in the active positions, the levers 70 point into opposite directions with respect to the longitudinal direction of the carrier 58.

In the third embodiment, abutment members 78 are provided in the movement range of the carrier 58. The abutment members 78 are stationary in the antenna 10. A lower abutment member 78 is provided in the movement path of the levers 70 with respect to a movement of the carrier 58, and upper abutment members 78 are in the movement path of the second part 76 of the locking mechanisms. The abutment members 78 are used to transfer the levers 70 from the active position into the inactive position and vice versa. Starting from the situation of Figure 8a, the carrier 58 is moved to the left. During this movement, the second part 76 of the locking mechanism of the left lever 70 is moved relative to the carrier 58 and against the bias of the elastic element 72 - more precisely, the second part 76 remains in place but the carrier 58 continues moving. Due to this movement, the first part 74 of the locking mechanism and with that the lever 70 is released as can be seen in Figure 8b. The elastic element 72 then holds the lever 70 in its active position.

Simultaneously, the lever 70 on the right-hand side comes in contact with the lower abutment member 78 and is rotated until the first part 74 of the locking mechanism engages with the second part 76, securely locking the lever 70 in the inactive position even when the carrier 58 is moved to the right again.

Figures 9a and 9b show the actuation assembly 31 of the third embodiment in use. On the right-hand side of Figures 9a and 9b, a second upper abutment member 78 for the right-hand lever 70 can be seen.

In the situation shown in Figure 9a, the lever 70 on the left-hand side is in the inactive position, the lever 70 on the right-hand side in the active position.

The actuation end 71 of the active lever 70 is already in contact with the actuation portion 66 of the hull 36 of the coupling assembly 30 to be engaged.

As the carrier 58 is moved further to the right, the lever 70 is rotated and the actuation end 71 is moved towards the hull 36, urging the hull 36 and the engagement member 34 into the engaged position. In particular, in the engaged position, the pivot of the lever 70 is axially aligned with the actuation portion 66 of the hull, as can be seen in Figure 9b.

To disengage, the carrier 58 may be moved to the left or right. When moving to the right, the coupling assembly 30 on the right-hand side may be engaged. At the same time, as the lever 70 on the left-hand side is in its inactive position, none of the coupling assemblies 30 on the left-hand side are actuated. The lever 70 on the left-hand side may be activated to actuate the coupling assemblies 30 on the left-hand side by moving the carrier 58 to the left as explained in the context of Figures 8a and 8b. A fourth embodiment of the invention is shown in Figure 10. This embodiment corresponds to the embodiment of Figures 8 and 9, only the locking mechanism is different.

In this embodiment, the second part 76 of the locking mechanism is an elongated member 80, like a rod or a plate, parallel to the carrier 58. The elongated member 80 may be moved relative to the carrier 58 in the longitudinal direction of the carrier 58.

The first parts 74 of the locking mechanism are recesses 82 in the levers 70 on the ends opposite to the actuation ends 71.

In the inactive position of a lever 70, the elongated member 80 engages in the recess 82 of the respective lever 70 and thus locks the lever 70 in place. The elongated member 80 has at least one, in the shown embodiment two catches 84. During movement of the carrier 58, one of the catches 84 comes into contact with the upper abutment member 78 (not shown in Fig. 10) and thus causes the movement of the elongated member 80 relative to the carrier 58. This movement simultaneously releases on of the levers 70 and locks the other one of the levers 70.

Figures 11 and 12 show a fifth embodiment of the invention. In this embodiment, the actuation assembly 31 is partly integrated into the coupling assembly 30, and the actuation of the engagement member 34 is realized by the use of magnetic forces. Figure 11 shows an exploded view of one of the coupling assemblies 30. The actuation assembly 31 comprises an electromagnet 86 and two magnetic elements 88. The electromagnet 86 is stationary and may be a solenoid concentric to the common axis A, and the electromagnet 86 can be regarded as the coupling actuator 26. The coupling actuator 26 and thus the electromagnet 86 may be controlled by the control unit 22 directly or via a power source 90 (Fig. 1). The magnetic elements 88 are arranged in the engagement member 34 and may be permanent magnets, ferromagnets or a combination thereof. The permanent magnets of the magnetic elements 88 may be a cascade of a plurality of smaller permanent magnets. Of course, the magnetic elements 88 may also be arranged on the engagement member 34. The engagement member 34 is therefore part of the coupling assembly 30 and the actuation assembly 31.

In the shown example, the engagement member 34 has a rod-like shape and extends through the electromagnet 86, in particular through the solenoid. The engagement member 34 is thus axially movable with respect to the electromagnet 86.

The magnetic elements 88 are arranged in the engagement member 34 asymmetrically in a way that none of the electromagnets lies in the center of the electromagnet 86 in the axial direction neither in the engaged position nor in the disengaged position. This arrangement avoids indifferent, unstable positions of the engagement member 34. Put differently, the magnetic elements 88 are arranged asymmetrically with respect to the electromagnet 86. More precisely, regarding a transverse plane T that extends in the middle between the axially most distant ends of the electromagnet 86 and transversely to the common axis A, the magnetic elements 88 are asymmetric with respect to the transverse plane T, in particular in the engaged position as well as in the disengaged position.

The coupling assembly 30 comprises a locking mechanism for the engagement member 34. In the shown embodiment, the locking mechanism comprises a spring-loaded ball 92 and two grooves 94 in the peripheral surface of the engagement member 34.

The grooves 94 extend along a full periphery of the engagement member 34 and are spaced apart in the axial direction by a distance corresponding to the distance that the engagement member 34 moves between the engaged position and the disengaged position.

The spring of the spring-loaded ball 92 is mounted to a stationary part of the antenna 10. The spring-loaded ball 92 is adapted to engage one of the grooves 94 and to axially hold the engagement member 34 even when the engagement member 34 is rotating.

Figures 12a to 12d show the working principle of the coupling assembly 30 and the actuation assembly 31 of this embodiment.

In the situation shown in Figure 12a, the engagement member 34 is in the disengaged position. The spring-loaded ball 92 is engaged in one of the grooves 94 and holds the engagement member 34 in place even when the electromagnet 86 is not energized. The electromagnet 86 has just been energized and generates a magnetic field in the region of the engagement member 34 that interacts with the magnetic elements 88. The magnetic force on the magnetic elements 88 is directed towards the engaged position, in Figure 12a upwardly. The engagement member thus moves in the engaged position shown in Figure 12b and engages with the input shaft 32 just like explained in context of the previous embodiments.

In the engaged position, the spring-loaded ball 92 engages with the other one of the grooves 94 holding the engagement member 34 in the engaged position even when the electromagnet 86 has been turned off.

In order to move the engagement member 34 from the engaged position to the disengaged position, the electromagnet 86 is energized again, but with inverse polarity. The magnetic field generated by the electromagnet 86 is therefore pointing in the opposite direction, downwards in Figure 12c, and leads to a force on the magnetic elements 88 in the direction towards the disengaged position. The engagement member 34 thus moves from the engaged position to the disengaged position and reaches the disengaged position shown in Figure 12d. As explained in context of Figure 12a, the spring-loaded ball 92 now engages the first grooves 94 again.

Each one of the coupling assemblies 30 is provided with a separate electromagnet 86 that can be controlled separately by the control unit 22. Thus, the coupling assemblies 30 can be addressed and controlled selectively.

This embodiment provides the advantage that fewer mechanical components for actuating the coupling assemblies are needed as only a power line has to be drawn from the control unit 22 or the power source 90 to each electromagnet 86. In order to limit the movement of the engagement member 34, the end faces 40 of the input shaft 32 and/or the output shaft 28 may be made of a ferromagnetic material. In this alternative, the magnetic elements 88 would be drawn towards the ferromagnetic end faces 40 which would also provide the locking mechanism. A locking mechanism with the spring-loaded ball 92 and two grooves 94 is not necessary in this case. To reduce the locking force, spacers may be introduced between the end faces 40 and the engagement member 34. Figures 13a to 13d show a sixth embodiment of the invention which essentially corresponds to the fifth embodiment of Figures 11 and 12.

In this sixth embodiment, the magnetic elements 88 are a cascade of ferromagnetic elements and two electromagnets 86 are provided in each coupling assembly 30.

The electromagnets 86 are spaced apart from one another in the axial direction and can be controlled separately by the control unit 22 and/or the power source 90.

Each of the magnetic elements 88 is associated with one of the electromagnets 86 and located at least partially outside of the associated electromagnet 86 in the axial direction facing away from the other one of the electromagnets 86. In order to move the engagement member 34 between the disengaged position and the engaged position, one of the electromagnets 86 is energized, being the lower magnetic element 88 in Figure 13a. The magnetic element 88 associated with the energized electromagnet 86 is drawn towards and further into the electromagnet 86, in the shown example upwards. This urges the entire engagement member 34 to move upwards and change from the disengaged position to the engaged position (Figure 13b) or vice versa. Both electromagnets 86 may then be turned off.

To reverse this movement, the other one of the electromagnets 86, here the upper one, is energized and the associated magnetic element 88 is drawn in the reverse direction into the magnetic element 88 (Figure 13c). This moves the entire engagement member 34 as well until the disengaged position is reached (Figure 13d).

It is to be noted that the polarity with which the electromagnets 86 are energized does not matter in this embodiment as ferromagnetic magnetic elements 88 are used. This simplifies the control unit 22 and power source 90.

Further, it is to be noted that also in this embodiment, the magnetic elements 88 are arranged asymmetrically with respect to the transverse planes T in both the engaged and disengaged position.

The features of the individual embodiments described above may be combined freely.

Some of the embodiments contemplated herein are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.