(A) Field of the Invention
The present invention is related to an angle adjustment apparatus of a dish antenna, and more specifically, to an adjustment apparatus for the fine tuning of the dish antenna angle using threads.
(B) Description of Related Art
A satellite television system employs a dish antenna to collect satellite signals, and the signals are then reflected to low noise block down converters (LNB) positioned at the focus of the dish antenna for amplifying the signals and reducing their frequencies down to around 1 GHz, i.e., the radio signals are transformed to an intermediate frequency. The adjusted signals are transmitted via a cable to an indoor television channel selector for selecting the signals of a desired channel, and the selected signals are then amplified, modulated and converted into video and audio signals for television viewing.
A dish antenna is a highly directional receiving device, which has to be precisely directed toward satellites in orbit at 36,000 kilometers altitude. For example, if a dish antenna with a 180 cm diameter shifts 2 cm horizontally, or 3 cm vertically, the signals will become weak or even disappear. In addition, if a dish antenna uses the Ka band, i.e., 26-40 GHz, an adjustment accuracy of 0.1 degrees is needed, and the tolerance has to be within 0.02 degrees for aiming at satellites precisely.
Normally, a dish antenna using the Ka band is adjusted by using a programmable logic controller (PLC) in control of servo motors; however, the high cost significantly limits its popularity.
The present invention provides an angle adjustment apparatus for a dish antenna. The angle adjustment apparatus utilizes threads to fine tune the orientation of the dish antenna. Therefore, the dish antenna can be precisely directed toward a transmitting satellite.
In accordance with an embodiment of the present invention, an angle adjustment apparatus for a dish antenna comprises a base, a first rotating frame, a second rotating frame, and a second rotation angle adjustment mechanism. The first rotating frame is fixed to the base, and can relatively rotate around the base with a first rotating angle. The second rotating frame is fixed to the first rotating frame, and can relatively rotate around the first rotating frame with a second rotating angle. The second rotation angle adjustment mechanism comprises a first screw rod, a screw nut post, and a second screw rod. One end of the first screw rod is fixed to the first rotating frame, and the other end is equipped with first threads and engaged with the screw nut post. One end of the second screw rod pivots on the second rotating frame, and the other end is equipped with second threads and engaged with the screw nut post. The first threads and second threads have different screw directions, or have the same screw direction but with different thread pitches.
In accordance with another embodiment of the present invention, a dish antenna apparatus comprises a dish, an angle adjustment apparatus, a support frame, and an adjustable stand. The dish is mounted on the angle adjustment apparatus, and the support frame connects the angle adjustment apparatus and the adjustable stand. The angle adjustment apparatus comprises a base, a first rotating frame, a second rotating frame, and a second rotation angle adjustment mechanism. The first rotating frame is fixed to the base, and can relatively rotate around the base with a first rotating angle. The second rotating frame is fixed to the first rotating frame, and can relatively rotate around the first rotating frame with a second rotating angle. The second rotation angle adjustment mechanism comprises a first screw rod, a screw nut post, and a second screw rod. One end of the first screw rod is fixed to the first rotating frame, and the other end is equipped with first threads and engaged with the screw nut post. One end of the second screw rod pivots on the second rotating frame, and the other end is equipped with second threads and engaged with the screw nut post. The first threads and second threads have different screw directions, or have the same screw direction but with different thread pitches.
The second rotation member 213 is secured to the first rotation member 212, and is capable of rotating by a first rotation angle α2 relative to the first rotation member 212. Referring to
As the fixed end 2145 of the first screw rod 2141 is secured to the first rotation member 212, the relative angle between the first rotation member 212 and the second rotation member 213 can be fine tuned by rotating the screw nut post 2142. That is, because the screw directions of the first threads and second threads are different, the first screw rod 2141 and the second screw rod 2143 are simultaneously close to or away from the screw nut post 2142. Consequentially, the first rotation member 212 and the second rotation member 213 rotate around a pivotal axis 216 (as shown in
Likewise, the screw rods 2151 and 2152 of the first rotating angle adjustment mechanism 215 and the screw nut post 2153 also have the same adjustment functions or analogous structures. The relative rotation movement starts between the first rotation member 212 and the base member 211 by rotating the screw nut post 2153 in a clockwise manner or in a counterclockwise manner. When the total length of the first rotating angle adjustment mechanism 215 is extended, the first rotation member 212 rotates counterclockwise around the base member 211. Alternatively, the first rotation member 212 rotates clockwise around the base member 211.
The above-described embodiments of the present invention are intended to be illustrative only. Numerous alternative embodiments may be devised by those skilled in the art without departing from the scope of the following claims.
Number | Date | Country | Kind |
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98114140 A | Jan 2009 | TW | national |
Number | Name | Date | Kind |
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7046210 | Brooker et al. | May 2006 | B1 |
7164391 | Lin et al. | Jan 2007 | B2 |
20050052335 | Chen | Mar 2005 | A1 |
Number | Date | Country | |
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20100177009 A1 | Jul 2010 | US |