EP2940785B1

EP2940785B1 - Satellite antenna, particularly for vehicles

Info

Publication number: EP2940785B1
Application number: EP15164629.6A
Authority: EP
Inventors: Raul Fabbri
Original assignee: Teleco SpA
Current assignee: Teleco SpA
Priority date: 2014-04-29
Filing date: 2015-04-22
Publication date: 2019-06-05
Anticipated expiration: 2035-04-22
Also published as: EP2940785A1

Description

The present invention relates to a satellite antenna, particularly for vehicles.
Various types of parabolic antennas, i.e., of devices which, as is known, are capable of receiving television transmissions sent by satellites located in geostationary orbit around the Earth, are currently commercially available.
In greater detail, in addition to the widespread installation of parabolic antennas on the roofs of buildings (mainly for private use but not only), antennas of the type indicated above mounted on top of vehicles are observed increasingly often.
Means of transport such as campers, truck campers, caravans, and recreational vehicles in general are frequently equipped with antennas that allow to use a television set located inside the living compartment.
With reference to this last specific field of application, the antennas are provided with motorized pointing means, which allow to vary the orientation of its fundamental components: the reflector dish and the device, usually termed LNB, that receives the signal reflected by the dish, converts it to a lower frequency and sends it to the decoder inside the vehicle.
More precisely, the motion of the antenna is usually controlled by two electric motors associated with respective gear systems, the first of which is assigned to rotation about a horizontal axis (parallel to the ground and to the roof of the vehicle, therefore, in order to allow antenna elevation) and the second of which is perpendicular to the first one and is assigned to azimuth rotation.
By way of these gear systems, it is possible to direct the antenna manually or automatically toward the satellite of interest and/or redirect it toward it even after a movement of the means of transport.
However, this constructive solution is not devoid of drawbacks.
The use of a pair of gear systems to control independently the rotation of the antenna about the two axes indicated above often causes bulk problems that are not easy to solve, especially if one wishes to obtain a high reduction ratio (in order to be able to perform precise pointings and to control rotations that correspond to angles of one degree or less).
Mostly, the surfaces of the mutually meshing sets of teeth are subjected to various stresses, which cause, for example due to wear, an excessively rapid deterioration, reducing often unacceptably the useful life of the gear systems.
It should also be noted that gear systems usually have play among the mutually meshing elements which are very difficult to eliminate but at the same time risk compromising the correct operation of the antenna, which has to be orientable with extreme prevision and minimal tolerances in the chosen direction in order to receive correctly the signal sent by the satellite.
Moreover, it should be noted that the gear systems are provided with electronic and mechanical sensors installed on the antenna frame and capable of detecting the reaching (on the part of at least one component of each gear system) of a stroke limit position, calibrated during initial installation, so as to correspond to the inactive configuration of the antenna. In this configuration, in which the antenna is indeed inactive, the dish faces the roof of the vehicle and is proximate thereto in order to minimize aerodynamic drag and facilitate the movement of the vehicle.
Therefore, a control and management unit, which controls the movement of the gear systems and of the antenna, is capable of detecting stroke limit reaching, preventing further motions (which might obviously damage the antenna and/or the vehicle) and can also impart, if necessary, a sort of "reset", i.e., control the movement of the antenna until the stroke limit is reached, if one wishes to render the antenna inactive and, for example, move the vehicle.
Usually, in order to achieve the goal indicated above and thus be able to send the information related to stroke limit reaching to a control and management unit, these sensors are capable of detecting the presence or proximity of a respective reference element, which is integral with the component of the gear the movement of which is being monitored.
However, if it is necessary to disassemble the gear systems, for example for maintenance or repairs, during the subsequent step of assembly it is very difficult, if not impossible, to restore the match, obtained as mentioned during first installation, between the stroke limit position and the inactive configuration of the antenna, thus generating additional drawbacks.
More generally, the need to provide valid control of stroke limit reaching causes structural complications that are not easy to solve for designers and for installation technicians.
US 4 887 091 A discloses a broadcasting receiver for vehicles having a combination of features as defined in the pre-characterizing portion of the appended claim 1.
The aim of the present invention is to solve the problems described above by providing a satellite antenna provided with gear systems intended to move the reflector dish which are capable of ensuring a high reduction ratio despite a modest space occupation.
Within this aim, an object of the invention is to provide a satellite antenna in which the gear systems assigned to dish motion are highly reliable and have a long life.
Another object of the invention is to provide an antenna in which the plays among the mutually meshing elements of the gear systems assigned to dish motion are extremely small.
Another object of the invention is to provide an antenna that allows to maintain the correct match between the inactive configuration and the stroke limit position of the driven gear systems assigned to dish motion even after their disassembly and reassembly.
Another object of the invention is to provide an antenna that ensures valid control of stroke limit reaching with a solution that is structurally simple.
Another object of the invention is to provide an antenna that can be obtained easily starting from commonly commercially available elements and materials.
Another object of the invention is to provide an antenna that is low cost and is safe in application.
In accordance with the invention, there is provided a satellite antenna, particularly for vehicles, as defined in the appended claims.
Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the antenna according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic perspective view of an antenna according to the invention, installed on top a vehicle;
Figure 2 is a schematic perspective view of the movement assembly;
Figure 3 is a schematic perspective view of a first gear system of the movement assembly;
Figure 4 is a partially exploded perspective view of the annular gear of the gear system shown in Figure 3;
Figure 5 is a schematic exploded perspective view of the annular gear of a second gear system of the movement assembly;
Figure 6 is a schematic exploded perspective view of the screw of the second gear of the movement assembly;
Figures 7 and 8 are schematic top views of details of the operation of the second gear system.

With reference to the figures, the reference numeral 1 generally designates a parabolic antenna, particularly for vehicles.
It is convenient to specify right now that in the preferred application the antenna 1 is indeed located on the top 2 of a vehicle, such as a camper, truck camper, caravan, truck, trailer truck, and the like, and therefore allows people who are in the living compartment of said vehicle to view television programs.
The protective scope claimed herein in any case includes the installation of the satellite antenna 1 on trucks, trailer trucks, and more generally on any vehicle capable of moving even over long distances and at the same time of allowing one or more people to dwell inside it (for example, therefore, also small or large watercrafts can be equipped with the antenna 1).
In any case, the antenna 1 comprises a movement assembly 3 for at least one reflector dish 4A, which in turn can be associated, in substantially known manner, with a device 4B for converting the signal transmitted by a predefined satellite and reflected by the dish 4A, in order to be able to thus send it to a decoder connected to the television set located in the dwelling compartment so as to allow occupants to view programs carried by the signal.
The device 4B can therefore be of the type commonly known by the term "LNB" (Low Noise Block Converter), or "feed".
The assembly 3 therefore comprises, in order to obtain the desired movement of the dish 4B, at least one motor 5, associated with at least one gear system 6a, 6b connected to the dish 4A, which thus actuates its rotation about at least one axis A, B and orients it toward the predefined satellite.
According to the invention, the gear system 6a, 6b comprises a worm screw 7a, 7b that meshes with an annular gear 8a, 8b that is selected of the twin-start type, so as to contain the overall bulk (as well as the play between said screw and said annular gear 8a, 8b) while allowing high reduction ratios and therefore achieving already at this point the intended aim.
In particular, in the preferred constructive solution that will be referenced in the continuation of the present description by way of non-limiting example of the application of the invention, the movement assembly 3 comprises a pair of motors 5, which are associated with respective gear systems 6a, 6b. Each gear system 6a, 6b thus comprises a worm screw 7a, 7b, of the twin-start type, which meshes with a respective annular gear 8a, 8b.
This specific constructive choice thus allows to control, in a mutually independent manner, respectively rotation about a first substantially horizontal axis A, in order to control the elevation of the dish 4A, and rotation about a second axis B, which is perpendicular to the first axis A, for azimuth rotation.
It must be stressed, therefore, that the protective scope claimed herein includes assemblies 3 of antennas 1 that comprise one or two gear systems 6a, 6b (or even more), capable of actuating rotation about one or two axes A, B (such as the ones cited above, but not only, as a function of the specific requirements of application), or even about a larger number.
Conveniently, the satellite antenna 1 also comprises at least one proximity sensor 9 of the electronic type that is capable of detecting the reaching, on the part of at least one reference element associated with at least one between the screw 7a, 7b and the annular gear 8a, 8b, of a gear system 6a, 6b, of a predefined angular position.
Said predefined angular position can be selected preferably, during initial installation, so as to correspond to an inactive configuration of the dish 4A, in which it is arranged substantially horizontally and facing the ground (or in any case facing the top 2 of the vehicle).
Obviously, it is specified that if the antenna 1 has two gear systems (as in the accompanying figures), it preferably also comprises two position sensors 9, each of which is assigned to detecting the respective predefined angular position for the corresponding gear system 6a, 6b. The inactive configuration of the dish 4A in this case is obtained when both gear systems 6a, 6b are in the respective predefined angular position, which in practice corresponds to a stroke limit.
It is specified, moreover, that in this inactive configuration the antenna 1 is inactive and the dish 4A is kept laterally adjacent and proximate to the top 2 of the vehicle, in order to minimize aerodynamic drag and facilitate the motion of said vehicle.
It is therefore important to identify, right from the first installation, the mutual arrangement assumed by the components of each gear system 6a, 6b, when the antenna 1 is arranged in said inactive configuration, so that subsequently the corresponding predefined angular position can be detected in a timely manner by the proximity sensor 9, which can thus transmit to a controller (or other unit for control and management of the motors 5) the information that the stroke limit has been reached.
In this manner, by way of the proximity sensor 9, the controller that controls the motors 5 can recognize the moment when the antenna 1 has reached the inactive configuration and can stop safely the movement of the dish 4A in order to prevent further rotations, which obviously might cause malfunctions and failures.
Furthermore, thanks to the possibility to detect in a timely manner the stroke limit position, the controller can offer, if needed, an automatic "reset" functionality: when required, the controller simply forces the antenna 1 (or the gear systems 6a, 6b) to rotate about the axes A, B until the stroke limit is reached, which corresponds to the inactive configuration of the antenna 1 and thus allows for example to move the vehicle.
It should be noted that the proximity sensor 9 can be of any kind, for example of the capacitive or magnetic or ultrasonic or other type, without thereby abandoning the protective scope claimed herein. Furthermore, the possibility to adopt also other types of sensor 9 (other than the proximity sensors 9), in any case capable of detecting the reaching of the predefined angular position, is provided.
In the embodiment shown in the accompanying figures, the sensor 9 is provided with a lamina 9A against which the reference element can abut (directly or indirectly) upon reaching the respective predefined angular position, which corresponds to the stroke limit. Contact with the lamina 9A is detected by the sensor 9, which can thus transmit the corresponding information to the controller.
Furthermore, proximate to the proximity sensor 9 there might also be a shoulder, against which the reference element is intended to abut if, for example due to a malfunction of said proximity sensor 9, its rotation is not stopped automatically at the stroke limit, thus preventing excessive rotations on the part of the antenna 1.
Hereinafter, in the continuation of the present description, merely by way of example, some constructive examples are given of the reference element (for specific gear systems 6a, 6b shown in the accompanying figures) and of the manners in which the proximity sensor 9 is capable of recognizing its reaching of the predefined angular position.
More generally, it is useful to note that the accompanying figures show, for the antenna 1 according to the invention, an embodiment of considerable practical interest (which, however, does not limit the application of the invention), in which the first gear system 6a (assigned for example to rotation about the first axis A and shown in detail in Figures 3 and 4) has different constructive details with respect to the second gear system 6b (assigned for example to rotation about the second axis B and shown in detail in Figures 5 to 8).
These different constructive details will be described in the pages that follow, but it is appropriate to specify that the protective scope claimed herein includes antennas 1 provided with gear systems 6a, 6b which are mutually substantially identical (and therefore of the type described hereinafter in relation to the first gear system 6a or the second gear system 6b or others) or also provided with a single gear system 6a, 6b (of any type) or of a number of gear systems 6a, 6b equal to or greater than three.
With particular reference to the first gear system 6a shown in the accompanying figures, it comprises therefore a reference pin 10, which is partially inserted radially and stably (by interference) in at least one respective channel 11, which is provided along a shaft 12a for supporting the annular gear 8a.
Positively, during initial installation and with the dish 4A arranged in the inactive configuration, the channel 11 can be aligned with the respective proximity sensor 9.
Thus, subsequently (during the operation of the antenna 1), the sensor 9 can detect automatically the reaching of the respective predefined angular position by a first end portion of the pin 10, which protrudes from the channel 11 and constitutes the reference element (and abuts against the lamina 9A when the gear system 6a reaches its stroke limit).
As already noted, this allows the controller to stop the rotation at the stroke limit or to impart the reset command when one wishes to move the antenna 1 to the inactive configuration.
Furthermore, the channel 11, provided along the shaft 12a of the annular gear 8a, is a through channel: this allows to define a first active configuration and a second active configuration that can be selected at will by means of the simple riveting of the pin 10 (to make it slide partially within the channel 11).
In the first active configuration, the pin 10 protrudes from the channel 11 with the first end portion (substantially as described in the preceding paragraphs and as shown in Figure 4), which as mentioned can be detected subsequently automatically by the proximity sensor 9 upon reaching a first predefined angular position.
Vice versa, in the second active configuration the pin 10 protrudes with a second end portion, which lies opposite the first end portion and constitutes the reference element in the second active configuration. This second portion, therefore, can be detected in turn automatically by the proximity sensor 9 (because it abuts against the lamina 9A), upon reaching a respective second predefined angular position.
It is thus evident that the second predefined angular position corresponds to a 180° rotation of the pin 10 and of the annular gear 8a with respect to the first predefined angular position detected by the sensor 9. Therefore, in a practical and easy manner (with the simple riveting of the pin 10), it is possible to ensure that the inactive configuration of the antenna 1 is in practice associated with two different predefined angular positions (which depend on the selected active configuration).
The advantage of this choice is associated with the fact that, having defined two different active configurations, in each one the annular gear 8a meshes with the screw 7a at respective angular portions, which are diametrically opposite and correspond to the maximum oscillation angle, about the corresponding rotation axis A, allowed to the dish 4A during normal operation.
In fact, it should be noted that in the normal operation of the antenna 1, the dish 4A moves about the first axis A without ever performing a complete rotation (through 360°), but simply by oscillating within a maximum angle, which is known beforehand by design and is in any case smaller than 180°.
First of all, therefore, as long as the active configuration in which the gear 6a works is kept unchanged, the annular gear 8a meshes with the screw 7a at a first angular portion, which is therefore the only portion, of the entire annular gear 8a, affected by the stresses produced by the transmission of power and therefore subject to wear and deterioration.
Upon reaching a limiting deterioration condition, it is possible to pass simply from the first active configuration to the second active configuration (by riveting the pin 10) in order to move the annular gear 8a so that it meshes with the screw 7a at a different angular portion, which is opposite the first one and in practice is still unused, and therefore has no deterioration or wear.
After riveting, the controller can in fact force the reset of the gear system 6a, and this causes the rotation of the annular gear 8a and of the shaft 12a until the second end portion (and no longer the first one) faces and is proximate to the sensor 9 (and abuts against the lamina 9A). From this position, the annular gear 8a oscillates within the maximum allowed angle, which defines a new angular portion of the annular gear 8a, which is diametrically opposite the one that meshes with the screw 7a in the first active configuration (and vice versa).
This allows obviously to increase significantly the useful life of the first gear system 6a and its reliability.
Even more particularly, in the embodiment shown by way of nonlimiting example in the accompanying figures, at least the annular gear 8a is fixed coaxially to a respective shaft 12a by way of stable coupling elements. Said stable coupling elements comprise first of all at least one key 13a (and for example two diametrically mutually opposite keys 13a, as in the example of the accompanying figures), substantially of a known type and interposed between the annular gear 8a and the respective shaft 12a.
In addition, in order to strenghten the coupling guaranteed by the key 13a, preventing both the rotation of the annular gear 8a about the shaft 12a and the axial sliding of the former on the latter, the stable coupling elements comprise also at least one grub screw 14a, that is inserted in a respective radial duct 15, defined in the corresponding annular gear 8a, up to the forced abutment on the shaft 12a (thus to prevent, by friction, the movement of the annular gear 8a with respect to the shaft 12a).
Favorably, the duct 15 is provided in the annular gear 8a outside of the already mentioned angular portions, which correspond to the maximum oscillation angle, which is smaller than 180°.
It should be noted, therefore, than indeed because both of the angular portions correspond to angles of less than 180° it is possible to identify angular sectors of the annular gear 8a that are never affected, in any of the two active configurations, by meshing with the screw 7a. In one of these sectors it is possible to provide the duct 15 without the necessary perforation of the set of teeth of the annular gear 8a causing malfunctions and poor meshing conditions.
This allows to ensure the stable coupling of the annular gear 8a to the respective shaft 12a without requiring the construction of coaxial sleeves, to be keyed on the shaft 12a and rendered integral with the annular gear 8a, because of the impossibility, which can be observed in similar known devices, to arrange stable coupling elements directly on the set of teeth of the annular gear 8a, as instead occurs in the antenna 1 according to the invention.
With reference to the embodiment of considerable practical interest, shown in detail in Figures 5 to 8 and related to the second gear system 6b, it should be noted that the latter comprises at least one first ring 16, which is arranged coaxially on a shaft 12b for supporting the respective ring 8b until it abuts and rests thereon.
The first ring 16 is provided externally with a radial protrusion 17, which constitutes the reference element for the second gear system 6b.
The first ring 16 therefore comprises detachable means 18 for coaxial anchoring to the shaft 12b, which can be actuated on command, during first installation and when the dish 4A is arranged in the inactive configuration, upon the abutment of a respective lever 19, pushed by the protrusion 17, on the lamina 9A of the respective proximity sensor 9.
In this manner, during the subsequent normal operation of the antenna 1 according to the invention, the proximity sensor 9 can detect automatically the reaching of the predefined angular position and send to the controller the information related to the fact that the dish 4A and the antenna 1 are in the inactive configuration.
In order to achieve this result, therefore, after moving the antenna 1 to the inactive configuration, during first installation it is possible to rotate the first ring 16 about the shaft 12b until the protrusion 17 presses against the arm 19, until it abuts against the lamina 9A of the respective proximity sensor 9 (in the position shown in Figure 8).
For this purpose, the arm 19 can rotate freely about a vertical direction.
The detachable means 18 (of which a possible embodiment will be given in the paragraphs that follow) allow to fix in a practical manner the mutual arrangement of the annular gear 8b and of the first ring 16 thus obtained, in order to maintain the constant match between the predefined angular position and the inactive configuration of the antenna 1.
If subsequently it becomes necessary to perform maintenance or repair activities, which entail the disassembly of the first ring 16 and of the annular element 8b, it is sufficient to repeat the operations described above to again restore the selected mutual arrangement and the correct match between the predefined angular position and the inactive configuration of the antenna 1.
In particular, the detachable means 18 comprise at least one first annular element 20, which is arranged coaxially on the shaft 12b so as to abut against the first ring 16 and is provided with a plurality of first radial teeth 21A, 21B.
Thanks to this particular constructive choice, upon the abutment of the arm 19 against the lamina 9A, by rotating appropriately the first annular element 20, a first tooth 21A, which protrudes inwardly, can be accommodated in a first groove 22 provided along the shaft 12b, so as to thus provide the coupling between the latter and the first annular element 20 (preventing rotations of the latter with respect to the former).
Furthermore, at least one other first tooth 21B (and for example two of them), which protrudes outwardly, can be folded until its forced abutment occurs against the first ring 16 in order to achieve the anchoring of the latter to the first ring 20.
The first ring 16 is provided with a plurality of tangentially distributed recesses 16A, one of which is always aligned with the first tooth 21B to be folded during installation to facilitate mutual coupling.
In turn, the annular gear 8b can be anchored stably to the shaft 12b by means of keys 13b, to be interposed between said components at the groove 22 and at at least one recess 8C provided inside the annular gear 8b.
It should be noted that during installation, after anchoring the annular gear 8b to the shaft 12b, it is possible to mount on the shaft 12b first the first ring 16 and then the first annular element 20, inserting the first tooth 21A in the groove 22. After rotating the first ring 16 about the shaft 12b until the protrusion 17 presses against the arm 19, at least one of the first teeth (and for example two) can be folded against the first ring 16, in order to complete the coupling.
In this manner, in fact, the shaft 12a, the annular gear 8a, the first ring 16 and the first annular element 20 are mutually stably coupled.
Conveniently, the detachable means 18 also comprise a second ring 23, which is arranged coaxially on the shaft 12b until it abuts and rests against the first annular element 20 and is in turn provided with a plurality of second radial teeth 24A, 24B.
Upon the abutment of the arm 19 against the lamina 9A, first of all a second tooth 24A, which protrudes internally, can be accommodated in a second groove 22, provided along the shaft 12b and arranged opposite the first one. In a manner fully similar, therefore, to what has been observed for the first tooth 24A of the first annular element 20, one obtains a coupling between the second annular element 23 and the shaft 12b.
Furthermore, at least one other second tooth 24B, which protrudes externally, can be folded by forcing toward the first annular element 20, until interlocking coupling occurs with respective first teeth 21B, which protrude externally from said annular element.
Furthermore, other second teeth 24B can be folded until they are brought into forced abutment against a second ring 25, which is arranged coaxially on the shaft 12b, on the opposite side with respect to the annular gear 8b, to lock the annular element 20, 23 against said annular gear and ensure the correct packing of said components.
In practice, therefore, once the preliminary operations described above have been completed, the mutual arrangement of the annular gear 8b and of the first ring 16 is fixed univocally, in order to maintain the constant correspondence between the predefined angular position and the inactive configuration of the antenna 1. By acting on the teeth 21A, 21B, 24A, 24B it is possible to disengage the annular elements 20, 23 from each other and disengage said annular elements from the rings 16, 25 and from the annular gear 8b, in order to perform the necessary maintenance or repair operations, to then repeat the steps described above and allow again the correct detection of the reaching of the predefined angular position.
It should be noted that for the gear system 6b, also, it is possible to provide a grub screw 14b in order to contribute to the stability of the coupling between the first ring 16 and the annular gear 8b.
Conveniently, the gear system 6b comprises means 26 for adjusting the position of the corresponding screw 7b with respect to at least one fixed supporting bracket thereof 27, in order to minimize play between the screw 7b and the corresponding annular gear 8b.
In an embodiment of considerable practical interest, which does not limit the application of the invention, the adjustment means 26 comprise at least one adjustment rod 28, which is perpendicular to the screw 7b.
The rod 28 is guided in the respective bracket 27 along an alternating rectilinear trajectory, which intersects the shank 29 of the screw 7b, so that it can be then moved by it into forced, optionally indirect, abutment against the screw 7b, and vary its position with respect to the corresponding annular gear 8b, minimizing mutual play.
It should be noted that the rod 28 can arrange itself directly in contact with the shank 29 or, in the constructive solution proposed in the accompanying figures, it can apply its thrust against a bearing that accommodates the shank 29.
Even more particularly, in the preferred constructive solution, which is visible in detail in Figure 6, the adjustment means 26 comprise two rods 28, which are mutually parallel and are guided in respective brackets 27 along corresponding trajectories of the type indicated above, in order to act at the two ends of the shank 29 of the screw 7b and vary its position with respect to the corresponding annular gear 8b.
With further reference to the preferred constructive solution, furthermore, each rod 28 is constituted by a threaded stem, which can move on command in a respective threaded seat 27A provided in the corresponding bracket 27.
Moreover, a respective shaped block 30 is interposed between the screw 7b and each rod 28 and is kept pressed, optionally indirectly, by the corresponding stem against the shank 29 of the screw 7b, in order to expand the contact surface and reduce the incidence of any deterioration and wear phenomena caused by the thrust applied by the rods 28.
It should be noted, moreover, that the block 30 can be accommodated in a recess 31 at least partially shaped complementarily to the block 30, so that the latter is accommodated substantially by interlocking in the recess 31 so that the walls of said recess positively oppose the lateral extraction of the block 30.
Operation of the antenna according to the invention is therefore evident from what has been described above.
In order to ensure the possibility to orient the dish 4A at will, directing it toward a predefined satellite, the controller controls the motors 5, which are in turn capable of imparting a rotation, about respective axes A, B, to mutually independent gear systems 6a, 6b which are connected to the dish 4A (and are supported on a base 32, which in turn can be anchored to the top 2 of the vehicle).
As already noted, the antenna 1 according to the invention achieves fully the intended aim, since the choice to resort to screws 7a, 7b of the twin-start type allows to contain the overall bulk (as well as the play between the screws themselves and the annular gears 8a, 8b) while allowing high reduction ratios.
Furthermore, the possibility to define two different active configurations, in each of which the annular gear 8a meshes with the screw 7a at respective diametrically opposite angular portions, ensures, as shown, a long life of the corresponding gear system 6a and therefore ensures maximum reliability.
Moreover, thanks to the means 26 for adjusting the position of the screw 7b with respect to its brackets 27, it is possible to minimize play between the screw 7b and the corresponding annular gear 8b, preset for movement of the dish 4A.
Furthermore, it should be stressed again that the particular constructive choices described in the preceding pages, related to the reference element that can be detected by the respective position sensor 9, allow, during first installation, to associate a predefined angular position of the gear systems 6a, 6b with the inactive configuration of the antenna 1, offering a valid control of the stroke limit and the possibility to maintain the correct match even after disassembly and reassembly of the affected components.
The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements, as long as they fall under the scope of the appended claims.
In the exemplary embodiments shown, individual characteristics, given in relation to specific examples, may actually be interchanged with other different characteristics that exist in other exemplary embodiments.
In particular, it should be noted that the solutions and refinements described in the preceding pages in relation to only one of the gear systems 6a, 6b can be extended to the other one of the gear systems 6a, 6b as well.
In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A satellite antenna, particularly for vehicles, comprising a movement assembly (3) for at least one reflector dish (4A), which can be associated with a device (4B) for converting the signal transmitted by a predefined satellite and reflected by said dish (4A), said assembly (3) comprising at least one motor (5), associated with at least one gear system (6a, 6b) connected to said dish (4A), for its controlled rotation about at least one axis (A, B) and its orientation toward the predefined satellite, said at least one gear system (6a, 6b) comprising a worm screw (7a, 7b) and an annular gear (8a, 8b) that mesh together, characterized in that said worm screw (7a, 7b) is of the twin-start type, and the antenna further comprising at least one proximity sensor (9) for detecting the reaching, on the part of at least one reference element associated with at least one between said screw (7a, 7b) and said annular gear (8a, 8b) of at least one said gear system (6a, 6b), of a respective predefined angular position, selected during initial installation, so as to correspond to an inactive configuration of said dish (4A), in which it is arranged substantially horizontally and facing the ground.
The satellite antenna according to claim 1, characterized in that said movement assembly (3) comprises a pair of said motors (5), which are associated with respective said gear systems (6a, 6b), comprising" corresponding said worm screws (7a, 7b) of the twin-start type, and said annular gears (8a, 8b), which mesh together, respectively for controlled rotation about a first said substantially horizontal axis (A), for the elevation at least of said dish (4A), and about a second said axis (B), which is perpendicular to said first axis (A), for azimuth rotation.
The satellite antenna according to one or more of the preceding claims, characterized in that at least one said gear (6a) comprises a reference pin (10), which is partially inserted radially and stably in at least one respective channel (11), which is provided along a shaft (12a) for supporting the respective said annular gear (8a) and can be aligned with a respective said proximity sensor (9), during initial installation and with said dish (4A) arranged in the inactive configuration, for subsequent automatic detection on the part of said proximity sensor (9) of the reaching of said respective predefined angular position on the part of a first end portion of said pin (10), which protrudes from said channel (11) and constitutes said reference element.
The satellite antenna according to claim 3, characterized in that said channel (11), provided along said shaft (12a) of said annular gear (8a), is a through channel, in order to define a first active configuration and a second active configuration, which can be selected at will by riveting said pin (10), in said first active configuration said pin (10) protruding from said channel (11) with said first end portion, which can be detected subsequently automatically by said proximity sensor (9) upon reaching a corresponding first said predefined angular position, in said second active configuration said pin (10) protruding from said channel (11) with a second end portion, which is opposite said first portion and constitutes said reference element in said second active configuration, said second portion being subsequently detectable automatically, by said proximity sensor (9), upon reaching a respective second said predefined angular position, which corresponds to a rotation through 180° of said pin (10) and of said annular gear (8a) with respect to said first predefined angular position, in each one of said active configurations said annular gear (8a) meshing with said screw (7a) at respective angular portions, which are diametrically opposite and correspond to the maximum angle of oscillation, about the corresponding said rotation axis (A), allowed to said dish (4A) during normal operation.
The satellite antenna according to one or more of claims 3 and 4, characterized in that at least one said annular gear (8a) is coupled coaxially to a respective shaft (12a) by way of stable coupling elements, which comprise at least one key (13a), which is interposed between said annular gear (8a) and the respective said shaft (12a), and at least one grub screw (14a), which is inserted in a respective radial duct (15) provided in said corresponding ring gear (8a) until forced abutment occurs against said shaft (12a), said duct (15) being provided outside said angular portions that correspond to said maximum oscillation angle, which is smaller than 180°.
The satellite antenna according to one or more of claims 1 and 2, characterized in that at least one said gear (6b) comprises at least one first ring (16), which is arranged coaxially on a shaft (12b) for supporting the respective said annular gear (8b) until it abuts against said annular gear (8b) and is provided externally with a radial protrusion (17), which constitutes said reference element, said first ring (16) comprising detachable means (18) for coaxial anchoring to said shaft (12b), which can be actuated on command, during first installation and with said dish (4A) arranged in the inactive configuration, upon the abutment of a respective arm (19), pushed by said protrusion (17), on a lamina (9A) of the respective said proximity sensor (9), for the subsequent automatic detection on the part of said proximity sensor (9) of the reaching of said predefined angular position.
The satellite antenna according to claim 6, characterized in that said detachable means (18) comprise at least one first annular element (20), which is arranged coaxially on said shaft (12b) until abutment occurs against said first ring (16) and is provided with a plurality of first radial teeth (21A, 21B), upon abutment of said arm (19) against said lamina (9A), a said first tooth (21A), which protrudes internally, being accommodatable in a first groove (22) provided along said shaft (12b), for the coupling between said first annular element (20) and said shaft (12b), at least one other said first tooth (21B), which protrudes externally, being foldable until its forced abutment occurs against said first ring (16), for the anchoring of said first ring (16) to said first annular element (20).
The satellite antenna according to claim 6, characterized in that said detachable means (18) comprise a second annular element (23), which is arranged coaxially on said shaft (12b) until it abuts against said first annular element (20) and is provided with a plurality of second radial teeth (24A, 24B), upon the abutment of said arm (19) against said lamina (9A), a said second tooth (24A), which protrudes internally, being accommodatable in a second slot (22) provided along said shaft (12b), for coupling between said second annular element (23) and said shaft (12b), at least one other said second tooth (24B), which protrudes externally, being foldable toward said first annular element (20), until interlocking coupling occurs with respective said first teeth (21B), which protrude externally, of said first annular element (20), other said second teeth (24B), which protrude externally, being foldable until their forced abutment occurs against a second ring (25), which is arranged coaxially on said shaft (12b), on the opposite side with respect to said annular gear (8b), in order to lock said annular elements (20, 23) against said annular gear (8b).
The satellite antenna according to one or more of the preceding claims, characterized in that at least one said gear system (6b) comprises means (26) for adjusting the position of the corresponding said screw (7b) with respect to at least one fixed supporting bracket (27) thereof, in order to minimize play between said screw (7b) and the corresponding said at least one annular gear (8b).
The satellite antenna according to claim 9, characterized in that said adjustment means (26) comprise at least one rod (28), which is perpendicular to said screw (7b) and is guided in said respective bracket (27) along an alternating straight path, which intersects the shank (29) of said screw (7b), for forced, optionally indirect abutment against said screw (7b), and for varying the position of said screw (7b) with respect to the corresponding said annular gear (8b), and for minimizing mutual play.
The satellite antenna according to claim 10, characterized in that said adjustment means (26) comprise two of said rods (28), which are mutually parallel and are guided in respective said brackets (27) along corresponding said paths, each one of said rods (28) being constituted by a threaded stem, which can move on command in a respective threaded seat (27A) provided in the corresponding said bracket (27), a respective contoured block (30) being interposed between said screw (7b) and each one of said rods (28) and being kept pressed, optionally indirectly, by the corresponding said stem against said shank (29).