Abstract:
A driving pinion drives two driven gears which are engaged with the driving pinion to rotate. Two drive bars which are fixed on the driven gears at a set radius respectively are inserted into two elongated openings of a frame which is pivoted on the driving pinion to make the frame seesaw, and then to make a coupler link which is borne on a stand, seesaw synchronously via a rocker mechanism having a four-bar linkage which is pivoted on both ends of the frame. Also, the stand is connected to an inclination adjusting mechanism, so that the inclination of the stand can be changed with respect to a horizontal plane.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a solar tracker, particularly to a solar tracker for mounting solar panel, wherein a rocker mechanism having a four-bar linkage is used to simplify solar panel mounting and reduce electrical energy required to direct a solar panel to the sun, and an inclination adjusting mechanism is used to adjust the inclination of the solar tracker based on different latitudes where the solar tracker is installed. 
         [0003]    2. Description of the Related Art 
         [0004]    In a previous US patent application, US 2009/0031647A1, (now patented) filed by one of the present inventors, a solar panel mounting structure is disclosed. In this structure, a pinion driven by a motor rotates two gears engaged with the pinion and located at its both sides, and a bar is fixed on each of these two gears at the same radius. On a frame for mounting a solar panel, two separated elongated openings are formed horizontally, and a circular opening is formed at the center between these two elongated openings. The bars on these two gears and the rotating shaft of the motor are inserted into the elongated openings and the circular opening respectively. Thus, when the motor rotates, these two gears are driven to rotate clockwise or counterclockwise. At the same time, in the elongated openings of the frame, the bars fixed on these two gears respectively force the frame to seesaw about the rotating shaft of the motor so as to follow variations in the distance between the bars and the rotating shaft. Therefore, the frame makes a seesaw movement to simulate sunrise and sunset just by controlling the rotation speed of the motor. 
         [0005]    In such a solar panel mounting structure, since the total weight of the solar panel is borne directly by the bars on these two gears and the rotating shaft of the motor, it is necessary to use a high-power motor and reinforce the structure of each component. Thus, it causes the whole structure to be bulky and awkward in miniaturization design. 
         [0006]    Furthermore, due to the connection relation between the frame and the gears, the frame must be set on one side of these gears (for example, a side away from the paper). In other words, when a large-scale solar panel is mounted on the frame, the solar panel is located on one side of the frame, so that the total weight of the solar panel is borne on a single side of the whole structure. In addition to the problem that blocking from the gears causes the solar panel to be mounted to the frame uneasily, such a structure needs to be reinforced as well in its whole unit in order to overcome the cantilever load induced by a single-side bearing. Consequently, the weight of the whole unit is further increased. 
       SUMMARY OF THE INVENTION 
       [0007]    In view of the above, the present invention is achieved by the inventors on the basis of the previous invention. Thus, not only the seesaw of the frame can be performed with lower power, but also the mounting of the solar panel becomes easier and the weight is not borne directly on these two gears and the motor. 
         [0008]    According to a solar tracker provided by the present invention, based on the solar panel mounting structure disclosed in the patent application, US 2009/0031647A1, filed by one of the present inventors, a rocker mechanism having a four-bar linkage is further mounted on the frame driven by the motor and the two gears. The rocker mechanism comprises two rockers, one end of each rocker pivoted to a corresponding end of the frame; and a coupler link, the two ends of which are pivoted to the other ends of the rockers respectively, and the center portion of which is pivoted on top of a stand. A solar panel will be mounted on the coupler link using the present invention. Thus, when the motor is controlled to rotate by the prior method stated above, the seesaw occurring on the frame will drive the coupler link via the rockers to seesaw synchronously. 
         [0009]    Therefore, using the structure of the present invention, the weight of the whole solar panel is borne by the central portion of the coupler link to reach an effect of a balance state. As long as a small push force and a small pull force are applied at these two ends of the coupler link respectively, it is quite easy to make the coupler link seesaw about its pivot at the center thereof. Therefore, the power required by the motor can be greatly reduced. This is an object of the present invention. 
         [0010]    According to the structure of the present invention, the weight of the whole solar panel is borne by the coupler link at the central portion of the mechanical structure when viewed from the top, so the requirement of reinforcement design on all components due to the cantilever load is avoided. Therefore, for the same material strength, the present invention can be significantly compacted. This is another object of the present invention. 
         [0011]    According to the structure of the present invention, the coupler link is located at the upmost position of the mechanical structure. Therefore, when the solar panel is mounted on the coupler link, it will not be blocked by other essential members. Consequently, the mounting job becomes much easier. This is a further object of the present invention. 
         [0012]    According to the structure of the present invention, to bear solar panel of same scale, a lower-power motor and a lighter mechanical structure can be used. Therefore, the solar tracker may be compact. This is still another object of the present invention. 
         [0013]    According to the structure of the present invention, an inclination adjusting mechanism is further attached. Thus, it is advantageous that the coupled link can be adjusted to face onto the sun based on different latitudes where the solar tracker is installed. This is yet another obj ect of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    A general configuration that implements the various features of the present invention will be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
           [0015]      FIG. 1  is a perspective view of a solar tracker of the present invention, wherein a stand is already adjusted into an inclined state. 
           [0016]      FIG. 2  is a front view of the solar tracker shown in  FIG. 1 , illustrating a coupler link in an inclined state at the midway of a solar tracking path. 
           [0017]      FIG. 3  is a front view of the solar tracker shown in  FIG. 2 , illustrating the coupler link in a horizontal state. 
           [0018]      FIG. 4  is a left-side view of the solar tracker shown in  FIG. 1 . 
           [0019]      FIG. 5  is a right-side view of the solar tracker shown in  FIG. 4 , wherein the stand is in an upright state. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    Firstly, referring to  FIG. 1  and  FIG. 2 , a solar tracker of the present invention mainly comprises: a dynamic mechanism  1 ; a rocker mechanism  2 ; and an inclination adjusting mechanism  3 . 
         [0021]    A motor and various control circuits thereof (not shown) are mounted inside a stand  4 . The rotating shaft  101  of the motor extends out of the stand  4  and fix a driving pinion  102 . 
         [0022]    Driven gears  103   a  and  103   b  are located at left and right sides of the driving pinion  102  and engaged with it, so that the driven gears  103   a  and  103   b  can rotate clockwise or counterclockwise about their own axles (shown with arrows), where these three axles are all aligned to each other. Also, drive bars  104   a  and  104   b  are fixed on the driven gears  103   a  and  103   b  at a predetermined radius respectively. A circular hole is made on the central portion of the horizontal line of a frame  105  to pivot the frame on the rotating shaft  101  of the motor, and two elongated openings  106   a  and  106   b  are formed on both sides of the central hole to the effect that the drive bars  104   a  and  104   b  fixed on the driven gears  103   a  and  103   b  can be inserted correspondingly into the elongated openings  106   a  and  106   b  respectively so as to slide freely. Thus, the dynamic mechanism  1  is comprised of the driving pinion  102 , the two driven gears  103   a  and  103   b  driven by the driving pinion  102 , the drive bars  104   a  and  104   b  fixed on the driven gears  103   a  and  103   b , and the frame  105  pivoted on the rotating shaft of the motor. 
         [0023]    Again, as shown in  FIG. 1  and  FIG. 2 , both ends of the frame  105  are pivoted on the rocker mechanism  2 . The rocker mechanism  2  is comprised of two rockers  201   a ,  201   b  and a coupler link  203 , wherein one end of each rocker  201   a  and  201   b  is pivoted on a corresponding end of the frame  105 , the other ends of the rocker  201   a  and  201   b  are pivoted on two ends of the coupler link  202  respectively, and the center portion of the coupler link  202  is pivoted on the top of the stand  4  through an axle  202   a . Preferably, a pair of right-angled bars  203   a  and  203   b  are fixed at both ends of the coupler link  202 , and the coupler link  202  are then pivoted on the rocker  201   a  and  201   b  via these two angle bars  203   a  and  203   b . Thus, the coupler link  202  on which a solar panel (not shown) will be mounted is located right over the central position of the stand  4  as viewed from the top, thereby preventing the coupler link  202  from being biased to one side of the stand  4 . It is an ideal machine design for weight balance. 
         [0024]    As shown in  FIG. 1  and  FIG. 3 , the stand  4  is mounted on a support bracket  5 , and can be turned around an axle pin  6 . A bottom portion  7  of the support bracket  5  functions as a base for a mounting site where the solar tracker will be installed. 
         [0025]    Referring to  FIG. 4  and  FIG. 5 , on both sides of the stand  4 , i.e., these two sides adjacent to the side on which the gears are mounted), numbers of locating holes  401   a  and  401   b  having equal intervals (for example, 15°) on a circumference with a predetermined radius from the axle pin  6  as a center of circle are formed. Simultaneously, on each side of the support bracket  5 , a locking hole is formed at a position with the same center of circle and radius, and a locking pin  8   a  and  8   b  can be inserted into a corresponding locating hole on these two sides of the stand  4  through the locking hole after the stand  4  turns to a desired degree, so that the stand  4  can be adjusted into a predetermined inclination state with respect to a horizontal plane as shown in  FIG. 4 . 
         [0026]    It is true that the above-stated inclination adjusting mechanism  3  for the stand  4  is used to only explain that the structure of the present invention further comprises a mechanism for adjusting the inclination of the stand  4  with respect to the horizontal plane. As a result, based on installation sites at different latitudes or different locations of the sun in different seasons, the solar panel mounted on the coupler link  202  can be flexibly adjusted by a user to face up the sun vertically so as to obtain the maximum solar radiant energy, thereby enhancing the effect of the present invention. Not only a prior mechanical detent is used for an inclination adjustment to the stand, but also there is an electrically-operated adjustment to the stand  4 , in which a gear is fixed on both sides of the stand  4  and driven by a driving pinion fixed on the support bracket  5  and driven by electrical power, to rotate a degree. Similarly, this can also achieve at adjusting the inclination of the stand  4 , and should be considered as within the scope of the present invention claimed. 
         [0027]    According to the solar tracker of the present invention, the solar panel will be mounted on the top surface of the coupler link  202 , and the weight of the solar panel is supported by the bearing (or the stand  4 ) to have an effect to reach a balance state. Therefore, as long as the right-angled bars  203   a  and  203   b  at both ends of the coupler link  202  are exerted by a small push-up force and a pull-down force, the plane of the coupler link  202  can be easily inclined to track the sun so as to obtain the maximum solar radiant energy. Consequently, the present invention can use a motor having a relatively small power. Furthermore, since the coupler link  202  is located at the central position of the top of the stand  4 , the major weight of the solar panel and coupler link are supported by the strength of the stand  4 . Therefore, the present invention can prevent the constituent members of the dynamic mechanism  1  from being damaged easily, thereby making their service life longer. 
         [0028]    Additionally, since the coupler link  202  is located at the upmost position over the stand  4  and far away from the constituent members, the solar panel may be mounted freely in sizes. 
         [0029]    With the inclination adjusting mechanism  3  additionally provided, it is convenient to adjust the inclination of the stand  4  mounted with the solar panel for the solar panel to face onto the sun and obtain the maximum solar radiant energy. 
         [0030]    Summing, the solar tracker of the present invention greatly enhances the effect of the solar panel mounting structure previously disclosed by one of the present inventors. 
         [0031]    It is to be understood that the present invention is not limited to the specific embodiments described above and that the invention can be embodied with the components modified without departing from the spirit and scope of the invention. 
         [0032]    This invention can be embodied in various forms according to appropriate combinations of the embodiments described above. For example, some components may be deleted from all of the components shown in each embodiment. Further, components in different embodiments may be used appropriately in combination.