Patent Publication Number: US-2011074651-A1

Title: Assembly of clamping mechanism and lnb and dish antenna using the same

Description:
BACKGROUND OF THE INVENTION 
     (A) Field of the Invention 
     The present invention is related to an assembly of a clamping mechanism and an LNB and a dish antenna using the same, and more specifically, to a fastening apparatus for the tuning of the dish antenna angle. 
     (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., 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 to 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. 
       FIG. 1  illustrates a known adjustable antenna apparatus  1  including a dish antenna  10 , an LNB  11 , a support rod  12 , an adjustable dish bracket  13 , a fixing arm  15 , and an adjustable base member  14 . When the adjustable antenna apparatus  1  is disposed in different manners by securing the adjustable base member  14  at different places such as a vertical wall surface or a horizontal or inclined roof, the adjustable dish bracket  13  is used for adjusting the orientation of the dish antenna  10  to obtain optimal signal-reception performance. When the fixing arm  15  is tightened to securely hold the LNB  11 , however, the LNB  11  cannot be easily adjusted to an optimal receiving position by tuning its angle. If receiving signals are still weak after the fixing arm  15  is fastened, the fixing arm  15  needs to be loosened for releasing the LNB  11 . The optimal receiving position is not easy to be properly set because of repeated assembly and disassembly, so the position adjustment is time-consuming. 
     SUMMARY OF THE INVENTION 
     The present invention provides an assembly of a clamping mechanism and an LNB and a dish antenna using the same. After the clamping mechanism and the LNB are combined, the angle of the LNB can be fine-tuned relative to the clamping mechanism while the clamping mechanism still holds the LNB. The fine angle adjustment is conducted while the LNB is fastened, and the clamping mechanism does not need to be unfastened. Consequently, the optimal receiving position is easily located, and the position is not by a screwing or fastening movement. 
     In accordance with an embodiment of the present invention, an assembly of a clamping mechanism and an LNB comprises a clamping mechanism and an LNB (low noise block down converter). The clamping mechanism includes a first clamping part, a second clamping part, and a plurality of rectangular grooves. The LNB includes a shell, at least one flexible portion, and at least one rib portion. The first clamping part and the second clamping part clasp around the LNB, and are combined with each other by at least one fastening part. The at least one flexible portion is disposed on the shell of the LNB, and the rib portion is on the flexible portion. The plurality of rectangular grooves are closely arranged in parallel on the inner surface of the second clamping, and the rib portion is contained in one of the rectangular grooves. By rotating the combination of the first clamping part and the second clamping part, the rib portion is forced to move between the rectangular grooves and then is positioned again. During the movement, the flexible portion is temporarily deformed. 
     In accordance with an embodiment of the present invention, a dish antenna comprises a dish, an LNB, a clamping mechanism, an angle adjustment apparatus, and an adjustable stand. The dish is mounted on the angle adjustment apparatus, and the angle adjustment apparatus is connected to the adjustable stand. The clamping mechanism is fixed on the dish, and includes a first clamping part, a second clamping part, and a plurality of rectangular grooves. The LNB includes a shell, at least one flexible portion, and at least one rib portion. The first clamping part and the second clamping part clasp around the LNB, and are combined with each other by at least one fastening part. The at least one flexible portion is disposed on the shell of the LNB, and the rib portion is on the flexible portion. The plurality of rectangular grooves are closely arranged in parallel on the inner surface of the second clamping part, and the rib portion is contained in one of the rectangular grooves. By rotating the combination of the first clamping part and the second clamping part, the rib portion is forced to move between the rectangular grooves and then is positioned again. During the movement, the flexible portion is temporarily deformed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective diagram showing a conventional adjustable antenna apparatus; 
         FIG. 2  is a perspective diagram showing an assembly of a clamping mechanism and an LNB in accordance with an embodiment of the present invention; 
         FIG. 3A  is an exploded diagram showing an assembly of a clamping mechanism and an LNB in accordance with an embodiment of the present invention; 
         FIG. 3B  is a partially magnified diagram of portion A in  FIG. 3A ; 
         FIG. 3C  is a partially magnified diagram of portion B in  FIG. 3B ; 
         FIG. 4A  is a schematic diagram of a flexible portion in accordance with an embodiment of the present invention; and 
         FIG. 4B  is a schematic diagram of ratchets in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 2  is a perspective diagram showing an assembly of a clamping mechanism and an LNB in accordance with an embodiment of the present invention.  FIG. 3A  is an exploded diagram showing an assembly of a clamping mechanism and an LNB in accordance with an embodiment of the present invention. The assembly  20  comprises a clamping mechanism  28  and an LNB  21 . The clamping mechanism  28  includes a first clamping part  22 , a second clamping part  23 , and at least one ratchet  221 . The LNB  21  includes a shell  211 , at least one flexible portion  212  (referring to  FIG. 3 ), and at least one rib portion  214  (referring to  FIG. 3 ). The first clamping part  22  and the second clamping part  23  clasp around the LNB  21 , and are combined with each other by at least one fastening part  24 . The first clamping part  22  and the second clamping part  23  are able to pivot relative to each other through a first pivoting portion  222  and a second pivoting portion  234 . The second clamping part  23  is connected to a connection arm  25 . The connection arm  25  is connected to a fixing arm (referring to reference numeral  15  in  FIG. 1 ) so as to be fixed to a dish (referring to reference numeral  10  in  FIG. 1 ). 
     As shown in  FIG. 3B , the at least one flexible portion  212  is disposed on the shell  211  of the LNB  21 , and the rib portion  214  is on the flexible portion  212 . The rib portion  214  comprises a detent part  2141  and two guiding parts  2142  disposed on two ends of the detent part  2141 . The rib portion  214  is not limited by the present embodiment, and has various changes its configuration. The two guiding parts  2142  make the rib portion  214  easy to move. In fact, the detent part  2141  by itself is enough for the embodiment and can function without the guiding parts  2142 . As shown in  FIG. 3C , the plurality of rectangular grooves  233  are closely arranged in parallel on the inner surface of the second clamping part  23 , and the rib portion  214  is contained in one of the rectangular grooves  233 . Each of the lateral guiding grooves  232  is on one side of the rectangular grooves  233  so the guiding parts  2142  on the two ends of the rib portion  214  can slide in the lateral guiding grooves  232 . The plurality of the rectangular grooves  233  and the lateral guiding grooves  232  are named as a ratchet  231 . As to the present embodiment, another ratchet  221  is disposed on the second clamping part  23 . Another rib portion (not shown) engaged in the ratchet  221  is opposite the rib portion  214  with a relative angle of 180° so the rotation motion for the position adjustment is more stable and the clamping force is also increased. The number of pairs of the rib portion and the ratchet is not limited by the present embodiment, and can be one or more. The rib portions and the ratchets can be disposed on the parting lines, but the rib portions and the ratchets of the present embodiment are not disposed on the parting lines. 
     By rotating the combination of the first clamping part  22  and the second clamping part  23 , the rib portion  2141  is forced to move between the rectangular grooves  233  and then is positioned again. During the movement, the flexible portion  212  is temporarily deformed. The flexible portion  212  is a cantilever defined by a C-shaped slit  213  on the shell  211 . When the combination of the first clamping part  22  and the second clamping part  23  is rotated, the rib portion  214  staying in one of the rectangular grooves  233  will mount a high partition between the rectangular grooves  233 , and then will fall into the next one of the rectangular grooves  233 . Accordingly, the flexible portion  212  can absorb force applied to the rib portion  214  by the second clamping part  23 . Because the shell  221  is partially pushed down, the rib portion  214  on it can successfully pass through the high partition between two rectangular grooves  233 . 
     When the combination of the first clamping part  22  and the second clamping part  23  is rotated, the finger  261  on the first clamping  22  or the second clamping  23  can be aligned with one of the angle indexes  262  on the shell  211  so the angle adjustment is easy and definite. To further stabilize and limit the rotation movement, an external guiding groove  272  is provided on the shell  211 . An external guiding rail  271  disposed on the first clamping part  22  can engage with the external guiding groove  272  so the external guiding rail  271  slides in the external guiding groove  272  and is constrained by the inner walls of the external guiding groove  272 . 
       FIG. 4A  shows a flexible portion  212 ′ in accordance with another embodiment of the present invention. The flexible portion  212 ′ is a cantilever defined by a semicircular-shaped slit  213 ′ on the shell  211 ′. The rib portion  214 ′ is provided on the surface of the flexible portion  212 ′. Compared with  FIG. 3 , there are no guiding parts on two ends of the rib portion  214 ′. 
       FIG. 4B  shows a ratchet in accordance with another embodiment of the present invention. To match the design of the rib portion  214 ′, the ratchet  231 ′ only comprises a plurality of adjacent grooves  233 ′. 
     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.