Abstract:
An antenna mount includes a frame formed by a front plate and a rear plate connected by a separator, which has a concave seat centrally located on its upper surface. A rotator element is pivotally secured between the front and rear plates, and is rotatable either clockwise or counterclockwise through the support frame. The upper portion of the rotator has a threaded opening into which an antenna can be mounted, while a spring mounted piston is provided at the bottom end of the rotator. When an antenna is mounted in the rotator and is upright, the piston is securely engaged on the seat. The antenna mount is installed on a vehicle so that upon encountering an obstacle while moving either forward or backward, the spring mounted piston becomes disengaged from the seat, causing the rotator and antenna to pivot either forward or backward in response to the force. The antenna can be reset by lifting the antenna until the antenna mount returns to a locked position and the antenna is again upright.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a mounting device for antennas, and more particularly for antennas used on vehicles which use tall antennas.  
       BACKGROUND OF THE INVENTION  
       [0002]     A typical aerial antenna mounted to the exterior body of the vehicle is constructed as a series of concentric segments which allow the antenna to be extended to a maximum length by “stretching” the antenna so that its segments are linearly arranged, and to be retracted by collapsing the segments down to the length of one segment. This type of construction, while acceptable for light duty antennas such as the antennas found on many cars, it is unsuitable for the large, heavy duty antennas mounted on military vehicles. As military equipment becomes more sophisticated and more reliant on radio or other airwave transmissions, more and more equipment are requiring mounted antennas mounted on the vehicles. Such military antennas are typically at least 15-20 feet tall and 1.5″ or larger in diameter at the base of the antenna. Thus, the mounting devices for mounting the antennas to the vehicles must be designed not only to be extremely strong to support such a large antenna, but also to withstand a significant amount of abuse, including extreme weather conditions and other elements of the environment that may be encountered in the field during military operations.  
         [0003]     When a heavy duty type antenna is mounted on a moving military vehicle and the antenna encounters an obstruction overhead of the vehicle, the impact of the antenna against the obstruction will cause the antenna to break. Although several different types of mounting devices and other protection devices have been developed to prevent antenna breakage due to obstructions, the designs are generally suitable only for light duty antennas and cannot withstand the size and conditions associated with military antennas. Accordingly, there is a need for an antenna mount which is suitable for use in military applications and which protects the antennas from breakage upon impact.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention provides an antenna mount which secures an antenna in an upright position while allowing the antenna to become disengaged from the upright position when the antenna encounters a low barrier or low clearance. Upon such impact, the antenna mount pivotally swings the entire antenna in the direction of impact. The antenna can then be reset by lifting the antenna until the antenna mount returns to a locked position at which the antenna is once again in an upright position.  
         [0005]     The antenna mount generally includes a front plate and a rear plate connected by a separator piece to form a support frame. The separator has a seat centrally located on the upper surface thereof. A rotator element is pivotally secured between the front plate and rear plate, and is configured to be rotatable either clockwise or counterclockwise. Additionally, the rotator is structured to enable an antenna to be mounted at the upper portion thereof, and includes spring mounted piston at the bottom thereof.  
         [0006]     When an antenna is mounted in the rotator and is upright, the piston at the bottom of the rotator is securely engaged on the seat provided on the separator. The antenna mount is installed on a vehicle so that upon encountering a lateral force in either the forward or backward direction relative to the direction of movement of the vehicle, the spring mounted piston is forced off the seat, whereupon the rotator and antenna pivots forward or backward in response to the lateral force applied against the antenna.  
         [0007]     These and other features and advantages of the invention will become apparent from the following detailed description, which is provided in connection with the accompanying drawings and illustrate an exemplary embodiment of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view of the antenna mount according to the present invention;  
         [0009]      FIG. 2  is an exploded view of the invention shown in  FIG. 1 ;  
         [0010]      FIG. 3  shows the rotator and bottom element of the invention shown in  FIG. 1 ;  
         [0011]      FIG. 4  is a side view of the rotator and bottom element shown in  FIG. 3 ;  
         [0012]      FIG. 5  is a front view of the rotator and bottom element shown in  FIG. 3 ;  
         [0013]      FIG. 6  is a cross-sectional view through the line VI-VI in  FIG. 1 ;  
         [0014]      FIG. 7  is a cross-sectional view through the line VII-VII in  FIG. 1 ;  
         [0015]      FIG. 8  shows the antenna mount of the present invention with the rotator rotated in a counterclockwise direction;  
         [0016]      FIG. 9  shows the antenna mount of the present invention with the rotator rotated in a clockwise direction;  
         [0017]      FIG. 10  shows a frame for securing the antenna mount to a vehicle. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]      FIG. 1  shows an antenna mount  10  according to an embodiment of the present invention, while  FIG. 2  shows an exploded view of the antenna mount  10 . Generally, the antenna mount  10  includes a front plate  40 , a back plate  50 , a separator  30  and a rotator  20 .  
         [0019]     As best seen in  FIG. 2 , front plate  40  has a pivot bore  45  formed through the thickness of the plate at an upper region thereof, and two parallel bores  46 ,  48  formed through the plate and near the bottom corners of the plate. Preferably, though not necessarily, the upper end of the front plate  40  has a rounded contour  42 .  
         [0020]     The structure of the back plate  50  is similar to that of the front plate  40  in that the back plate  50  also has a pivot bore  55  extending through the thickness of the plate and a pair of parallel bores  58  (only one shown in  FIG. 2 ) formed through the plate near the bottom corners thereof. Additionally, back plate  50  also includes two additional pairs of bores  52 ,  54  and  56  (only one shown in  FIG. 2 ).  
         [0021]     As illustrated in  FIGS. 2-5 , the separator  30  has a shallow hole  33  formed at the center of the top surface thereof, and a pair of parallel bores  34 ,  36  extending through the separator  30  in the direction “ts” ( FIGS. 1, 4 ). The bores  34 ,  36  of the separator  30 , the bores  46 ,  48  of the front plate  40  and the bores  58  of the back plate  50  are formed so as to become aligned to form one continuous bore when the separator is sandwiched between the front and back plates. A seat  35  having a cylindrical bottom portion and a concave disc portion  38  is affixed in the separator with the cylindrical portion fitted into the hole  33  and the concave disc  38  flush with or having an outer periphery thereof sitting directly on the upper surface of the separator  30 . Optionally, the concave disc portion  38  may include a lip around the periphery of the disc.  
         [0022]     Rotator  20 , as best seen in  FIGS. 3-5 , is generally shaped like an upside-down “L,” with the horizontal portion being formed as a mounting platform  22  and the vertical portion forming a pendulum section  24  of the rotator. The lower end  26  of the pendulum section  24  preferably has a rounded contour to allow the rotator to rotate as will be described further on in this description of the invention.  
         [0023]     A threaded antenna bore  23  is formed through the overhanging plane of the mounting platform  22  for engaging the base portion of an antenna (not shown). Although it is preferable to have the threaded antenna bore  23  formed all the way through the mounting platform  22 , it is not necessary to do so, as the threaded antenna bore  23  may be formed only partially through the mounting platform  22 . Furthermore, the present invention may be provided with other suitable types of mechanisms or arrangements instead of a threaded antenna bore  23 , for securing an antenna to the rotator  20 , such as a clamp, matingly shaped connectors on the antenna and the rotator, adhesives, etc.  
         [0024]     In addition to the antenna bore  23 , rotator  20  also provides a spring bore  25  formed centrally through the entire length of the pendulum section  24  and which is threaded at the top end  28  thereof. A pivot bore  27  is formed perpendicularly to spring bore  25 , along the direction “t R ” through the pendulum section  24 . A pin bore  29  is formed perpendicularly to both the spring bore  25  and pivot bore  27 , along the direction “w R ” of the pendulum section  24 . Both pivot bore  27  and pin bore  29  intersect and pass through spring bore  25 , but are spaced apart from each other along the length “l R ” of the spring bore  25  with pin bore  29  being positioned slightly below the pivot bore  27 .  
         [0025]     Although the pin bore  29  is described in the exemplary embodiment as extending along the direction “w R ” of the pendulum section  24  and perpendicular to the pivot bore  27 , it is not necessary to orient the pin bore  29  in this manner. Alternatively, pin bore  29  may be formed parallel to the pivot bore or along any other desired angle to pivot bore  27 , as long as the pin bore  29  is located below the pivot bore  27 . Furthermore, the pin bore  29  is shown in the figures as extending through the entire width of the pendulum section  24 , but it can be formed to be shorter as long as it intersects and passes through the spring bore  25 .  
         [0026]     As can be seen from  FIGS. 2 and 6 - 7 , a spring and piston assembly are placed in the spring shaft  25  with the tip  76   a  of the piston  76  protruding from the rounded bottom of the pendulum section  24 . The bottom end of spring  74  contacts or may be frictionally fit around the cylindrical portion  76   b  of the piston  76 . Both the diameter of the cylindrical portion  76   b  of piston  76  and the outer diameter of the spring are sufficiently smaller than the diameter of the spring bore  25  so that the spring  74  can be compressed freely without being frictionally hindered by the wall of the spring bore  25 . The spring bore  25  may be formed with a shoulder or fitted with a snap ring at the bottom opening, which enables the tip  76   a  of the piston to protrude from the end of the spring bore  25  while preventing the piston  76  and spring  74  from slipping out of the spring bore  25 . The spring  74  has a natural length at least equal to the length measured from the bottom of the spring shaft  25  to the pin bore  29 .  
         [0027]     A pin  82  is inserted into the pin bore  29  across the top of spring  76  to thus prevent the spring  76  from extending or being pushed up into the region of the pivot bore  27 . The spring bore  25  is closed off at the top by a cap  78  screwed into the threaded portion at the top of the bore, so as to prevent debris from entering the bore.  
         [0028]     Assembly of the antenna mount is achieved by aligning the bores  46 ,  48 ,  34 ,  36 , and  58  of the front plate  40 , separator  30  and back plate  50 , respectively, and joining these three pieces together with a pair of bolts  84 ,  86  through the pair of continuous bores formed by the aligned pairs of bores through the front and back plates and the separator. When joined together, the front and back plates and the separator form a U-shaped frame.  
         [0029]     The rotator  20 , which has the spring  74 , piston  76 , pin  82  and cap  78  appropriately assembled in the spring bore  25 , is then placed between the front and back plates in the U-shaped frame, with the piston  76  resting on the concave surface  38  of the seat  32  and the mounting platform  22  of the rotator  20  overhanging the (rounded upper end of) front plate  40 .  
         [0030]     The rotator  20  is secured to the frame by pushing down slightly on the rotator  20  to align the pivot bores  45 ,  27  and  55 , and then inserting a shaft  72  into the aligned pivot bores. The diameters of the shaft  72  and the pivot bores  45 ,  27  and  55  are preferably dimensioned so that the shaft  72  is frictionally fitted into the bores  45  and  55  of the front plate  40  and the back plate  50 , respectively, while the diameter of the pivot bore  27  in the rotator is slightly greater than that of pivot bores  45  and  55  so that rotator  20  can pivot readily around the shaft  27 . Optionally, the ends of the shaft  27  may be even more securely affixed in the bores  45  and  55  using adhesives, welding, and/or other means. Also, the diameters of bores  45  and  55  can be made to be equal to the diameter of bore  27 , perhaps for simplifying the manufacture of the component parts in the device.  
         [0031]     When the rotator  20  is pushed down on the separator  30  and then held in this position by the shaft  72 , the spring  74  becomes slightly compressed and the piston  76  is pressed against the concave surface  38  of the seat  32 . By biasing the piston against the seat  32 , this position of the rotator  20  becomes particularly stable and requires a predetermined amount of force to move the rotator  20  out of this position, which depends on the spring constant k. The higher the spring constant k, the “stiffer” the spring becomes, which causes the piston  76  to press harder against the seat  38 , which in turn requires a greater force to overcome this force to push the piston  76  off the seat  38 . If the seat  38  is formed with the optional lip around the periphery thereof, the piston engages the seat even more stably. When the piston  76  is in this stable arrangement with the seat  38 , the rotator  20 , and hence any antenna mounted in the antenna bore  23 , are in the upright position.  
         [0032]     When an antenna is mounted in the antenna mount  10  and the antenna encounters an obstruction or lateral force sufficient to overcome the bias force of the spring  74  pushing the piston  76  against the seat  38 , the piston  76  is pushed off the seat  38  as the rotator pivots around shaft  72  in the direction of the force. The amount of force required to disengage the piston can be tailored to a desired or predetermined level by using a spring having the appropriate spring constant k. Once the piston is disengaged off the seat  38 , the antenna falls to a horizontal position to safely clear the source of the lateral force without bending or breaking the antenna. The antenna can be easily restored to the upright position by raising the antenna until the piston “snaps” back into position on the seat  38 .  
         [0033]     As shown in  FIGS. 8 and 9 , the rotator is capable of pivoting either clockwise or counterclockwise around the shaft  72 . Such capability is advantageous in that when the antenna mount is mounted to a vehicle, the antenna can be protected from breakage upon encountering any obstacle, no matter if the vehicle is moving forward or backward.  
         [0034]     The antenna mount may be constructed of an anticorrosive and lightweight but sturdy material, such as aluminum or aluminum alloys, or a high tensile strength industrial plastic. The sturdy design of the antenna mount easily enables the device to accommodate the 15-20+ ft. height of military antennas and to withstand harsh and abusive environments and conditions, while the relatively simple structure reduces the possibilities for failure or breakage, and are easy to maintain and/or repair should it become necessary.  
         [0035]     A military vehicle will often require the use of several antennas, thus requiring that several of the antenna mounts be affixed to the vehicle. A typical arrangement for securing the antenna mount to the vehicle is shown in  FIG. 10 . The frame  90  is a part of a telescoping antenna base which is raised to receive and transmit signals. The frame includes a plurality of brackets  60 , as also shown in  FIG. 2 .  
         [0036]     Each bracket  60  includes a plurality of throughholes  62 ,  64 ,  66 ,  68  for screwed or bolted to the back plate  50  of the antenna mount. For this purpose, back plate  50  also includes a corresponding set of throughholes  52 ,  54 ,  58  (one note shown) formed in alignment with the positions of the throughholes formed in the bracket  60 . Preferably, each bracket  60  also includes a pivot bore  65  formed in alignment with the bores  55 ,  27  and  45  of the back plate  50 , the rotator  20  and the front plate  40 . With the pivot bore  65 , the pivot shaft  72  may be inserted beyond the back plate  50  into the bracket  65 , which provides for even more stability in securing the antenna mount to the vehicle and in supporting the weight of the antenna.  
         [0037]     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.