Abstract:
A tracking device for solar modules includes a post for purposes of the indirect and/or direct arrangement of a cradle unit, which can be rotated via a rotary joint about an axis of rotation, wherein the cradle unit comprises two force introduction regions, opposed with respect to the rotary joint, for purposes of rotating the cradle unit, wherein a force introduction takes place by a substantially circular segment-shaped guide element, and wherein a radius of the substantially circular segment-shaped guide element corresponds to a distance between the respective force introduction region and the rotary joint.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention concerns a tracking device for solar modules, a transverse row of tracking devices, a longitudinal row of tracking devices, together with a solar module field. 
         [0002]    Tracking devices for solar modules of the types in question are fundamentally of known prior art. They serve the purpose of pivoting or rotating solar modules, or solar module tables, such that their inclination can be optimally matched to the solar radiation, ultimately in order to optimise the efficiency of such systems. For purposes of pivoting the solar modules or solar module tables, push rods or traction elements such as cables are, for example, of known prior art. The solutions of known art, however, often have a wide variety of design deficiencies. Thus tracking devices with pushrods as a rule include many bearing points and have kinematics that are unfavourable during the pivoting process, which makes these systems expensive and susceptible to faults. If cables are deployed for purposes of pivoting the solar modules or solar module tables the challenge exists in maintaining their tensions within an optimal range. Depending upon the fundamental design, the result is often in particular a slackening of the cable tensions, which makes such tracking devices for the most part extremely unstable. 
         [0003]    It is therefore the object of the present invention to specify a tracking device for solar modules, a transverse row of tracking devices, a longitudinal row of tracking devices, together with a solar module field, which avoid the above-cited disadvantages and at the same time are designed so as to be extremely simple and cost-effective. 
       SUMMARY OF THE INVENTION 
       [0004]    In accordance with the invention a tracking device for solar modules comprises a post for purposes of the indirect and/or direct arrangement of a cradle unit, which can be rotated via a rotary joint about an axis of rotation, wherein the cradle unit comprises two force introduction regions, opposed with respect to the rotary joint, for purposes of rotating the cradle unit, wherein force introduction takes place via an at least essentially circular segment-shaped guide element, and wherein a radius of the circular segment-shaped guide element corresponds to a distance between the respective force introduction region and the rotary joint. 
         [0005]    As stated in the introduction, the tracking device serves in the first instance the purpose of adapting the inclination of one or a plurality of solar modules, i.e. photovoltaic modules, to the position of the sun. A solar, or photovoltaic, module converts the light of the sun&#39;s rays into electrical energy, wherein the efficiency can be optimised if the sun&#39;s rays impinge onto the solar, or photovoltaic, modules at an ideal angle. The tracking device can advantageously also be deployed for other systems operating in accordance with the principle which can be summarised by the term “solarthermics”, thus in other words, for example, for purposes in general of pivoting solar collectors or solar mirrors (e.g. parabolic mirrors) of any kind. 
         [0006]    The actual pivoting movement or rotation advantageously takes place via one or a plurality of traction elements, such as, for example, (wire) cables. However, other materials can also be deployed, or also other traction elements, such as chains or similar. 
         [0007]    The force introduction advantageously takes place by means of the essentially circular segment-shaped guide element. An (imaginary) centre point of the circular segment-shaped guide element lies essentially at the point of rotation. The background to this arrangement is that the one or more force introduction regions during the pivoting movement of the cradle unit ultimately also describe a circular arc, or a circular segment, which process, without the use of the guide elements, can lead to a slackening of tension in the traction elements, in other words, that is to say, in the cable tension. If a traction element originating from a fixed point, which is disposed, for example, on the post, is directly connected, that is to say without the guide element, to one of the force introduction regions, the distance between the above-cited fixed point and the force introduction region alters by a certain amount as the cradle unit pivots, for example, through 10° from the horizontal in an anticlockwise sense. If the cradle unit pivots through 10° from the horizontal in the clockwise sense, the distance between the fixed point and the force introduction region similarly alters by a certain amount. However, the latter amount does not correspond in length to the above-cited amount that occurs during pivoting in the anticlockwise sense. Fundamentally this fact leads to the challenge, or problem, that the cable tension in such systems can slacken in an unreliable manner. In particular it is, for example, not possible to connect two adjacent cradle units by means of a traction element such that a pivoting movement of the one cradle unit can be transferred by means of the traction element onto the other cradle unit, without the tension in the traction element slackening in an unreliable manner. Also the two force introduction regions of a tracking device cannot, for example, be connected by means of a roller, which is attached to the post, without the result being the above-cited length problem and at the same time a slackening of the cable tension. 
         [0008]    However, the circular segment-shaped guide element is advantageously provided, as a result of which the above-cited problem can be avoided. The distance between the above-cited fixed point and the corresponding force introduction region is always held constant by the guide element in that it follows the guide element or is prescribed by the latter. The guide element and the cradle unit are preferably arranged and designed relative to one another such that the force introduction takes place essentially at right angles to the cradle unit. Therefore, the force, which causes the rotation or the pivoting movement of the cradle unit, acts tangentially to the guide element. The force introduction advantageously takes place directly on the cradle unit. The force that causes the cradle unit to be pivoted always engages therefore in the region of the cradle unit and is guided by the guide element. The guide element is advantageously designed so as to redirect the force, in particular the traction force, which causes the rotational movement of the cradle unit. In a preferred form of embodiment the one or more traction elements run essentially at right angles, or transverse, to the post and are then guided by the traction elements onto the force introduction region, and are thus appropriately redirected. The radius of the guide element, which corresponds to the distance between the respective force introduction region and the rotary joint, can also be interpreted as a lever arm with which the force for purposes of rotating or pivoting the cradle unit acts on the latter. Here the lever arm acts essentially transverse to a vertical axis of the post. By virtue of the fact that the guide element is designed to be essentially of a circular segment shape, the lever arm, even if the cradle unit is pivoted to its maximum extent, always remains the same size. Solutions from the known prior art, which operate with rigid push rods, which pivot the cradle units by means of straight beams, have the disadvantage that during the pivoting of the cradle unit into a tilted position they can on occasion have only a very small lever arm. This increases the forces that are required for the pivoting process, together with the holding forces, and brings an extreme instability into the system. All of these disadvantages are however prevented by means of the circular segment-shaped guide element, which always provides a lever arm of the same size for the force introduction process. 
         [0009]    The guide element is preferably attached onto the cradle unit, wherein a traction element is attached in or on the force introduction region. The guide element can be materially bonded to the cradle unit; that is to say, it can be welded, for example. Likewise preferred is also a form fit and/or a force fit connection with screws, bolts, pins, or rivets, etc. In one form of embodiment the traction element takes the form of a cable, in particular a wire cable. The traction element can be attached both to the guide element, and also to the cradle unit. What is crucial is that it is attached in or on the force introduction region. The force introduction region is understood to be the region in which the introduction of force takes place. As a rule, this is the region in which the guide element is attached to the cradle unit, and in particular onto the above-cited transverse beam. In preferred forms of embodiment, the arrangement and attachment of the traction element in or on the force introduction region takes place via a type of tension unit or similar. Such a tension unit, which can, for example, consist of one or a plurality of springs, is designed to compensate for tension peaks in the traction element and, on occasion, also to serve the purpose of maintaining a certain basic tension in the one or more traction elements. However, it is not necessary for each traction element to be provided with such a tension unit, rather the arrangement of the traction element can also take place in a more or less fixed manner in that, for example, a thread is pressed onto one end of the traction element, so that the traction element can be screwed on for purposes of attachment. 
         [0010]    In a preferred form of embodiment the cradle unit comprises a transverse beam, which is attached essentially centrally on the rotary joint, wherein alignment takes place such that it extends essentially at right angles or transverse to the axis of rotation. Longitudinal beams are preferably arranged and attached at both ends of the transverse beam; these extend along, i.e. parallel to, the axis of rotation. Here the attachment and arrangement can take place as a form fit, and/or a force fit, and/or a material bond. The transverse beam is advantageously formed from a closed profile, in particular a closed metal profile, such as, for example, a square profile, wherein the cross-section can be both square and rectangular. Similar considerations apply for the longitudinal beams, which in one form of embodiment are likewise formed from a closed profile, in particular a metal profile with, for example, a square or a rectangular cross-section. The metal preferably takes the form of steel or aluminium. Alternatively the above-cited profile cross-sections can also take the form of open profiles, such as, for example, double-T beams, U-profiles, or sigma profiles. 
         [0011]    The rotary joint need not be directly attached to the post; rather it can also be attached to a headpiece, which in turn is connected to the post. Such a headpiece enables an individual adaptation of the height of the rotary joint and thus of the cradle unit, without the need for the post, which is secured in foundations in the ground, to be moved, or for its location to be altered. In one form of embodiment the rotary joint itself is formed from a commercially available and appropriately dimensioned bearing. Bearings that allow a certain movement, i.e. flexibility, about a vertical axis of the post, and/or along the axis of rotation, can also advantageously be deployed. In this manner tolerances in the location and position of tracking devices or posts aligned along a longitudinal axis can be compensated for. This is of particular advantage if these are connected via a common cradle unit or a common solar module table. 
         [0012]    One or a plurality of solar modules can be arranged on the cradle unit, wherein an arrangement of a plurality of solar modules on the cradle unit is also called a solar module table. Here the arrangement of the solar modules on the cradle unit can take place directly, or immediately, for example by means of screws, rivets, bolts, pins, or similar. It can, however, also take place indirectly, or not immediately, via module beam rails, etc., which are arranged between the solar modules and the cradle unit. 
         [0013]    In a preferred form of embodiment the circular segment-shaped guide element has essentially a semicircular shape. The semicircular-shaped guide element with its two ends is advantageously attached to the cradle unit, i.e. is attached to the two opposing force introduction regions on the above-cited transverse beams in a form fit, and/or a force fit, and/or a material bond. Here it must, however, be noted that in the case of both the circular segment-shaped guide element and also the semicircular-shaped guide element it is always true that here no ideal circular segment or no ideal semicircle can be meant in the mathematical sense. Production tolerances must always be taken into account in such systems. For the function of the guide element as already described it is moreover not important for it to take the form of an ideal circular segment or an ideal semicircle. In the final analysis, both the circular segment and also the semicircle could be composed from a multiplicity of straight sections or pieces, so that in the overall view a circular segment or a semicircle is again generated or approximated. By the same token, the guide element can also be formed from a multiplicity of rollers, which are essentially arranged in a semicircular shape, or in a circular segment shape. The force introduction region or regions, which are located on the cradle unit, describe a circular arc when the cradle unit pivots or rotates about the rotary joint. The guide element has the task of guiding the force, that is to say, for example, the traction element, such that the force likewise always acts along the said circular arc. In order to ensure the function, however, it is not necessary for the guide element to have an exact circular segment shape. However, it is preferable if an ideal circular arc or circular segment shape is approximated as well as possible. 
         [0014]    In one form of embodiment the guide element is designed to guide one or a plurality of traction elements in a plane standing at least essentially at right angles to the axis of rotation. Since the cradle unit comprises two force introduction regions, opposed with respect to the rotary joint, for purposes of rotating the cradle unit, for example, for purposes of rotating the cradle unit in the clockwise sense, and for purposes of rotating the cradle unit in the anticlockwise sense, the guide element is preferably designed so as to guide one or a plurality of traction elements in the plane standing at least essentially at right angles to the axis of rotation. 
         [0015]    The guide element is preferably bent out of a profile, in particular a metal profile, wherein the profile is preferably a U-profile. Such a U-profile advantageously forms a channel in which one or a plurality of traction elements can be guided. The guide element can also comprise a plurality of such channels, for example, two channels, such that one channel is provided for each traction element for guidance purposes. 
         [0016]    The rotary joint is advantageously arranged at a distance from the ground surface, wherein the ratio of the radius of the guide element to the said distance preferably lies in a range from about 0.8 to 0.98. This indicates that the traction elements, that is to say, in particular the wire cables, which are required for purposes of pivoting and rotating the cradle units, run sufficiently close to the ground such that it is possible to drive over them. Solar module fields, which comprise a multiplicity of tracking devices for solar modules, can thus be easily accessed on foot and also by vehicle, which greatly simplifies the maintenance, support and care of such facilities. By virtue of the fact that the guide element guides the one or more traction elements, the traction elements always remain close to the ground, even during the pivoting or rotation of the cradle units. If the traction element when driven over e.g. by a vehicle is pressed slightly downwards, this can advantageously be compensated for by means of the tensioning unit previously referred to, or in a totally general manner, by means of a more or less flexible or elastic attachment of the traction elements to the force introduction region. 
         [0017]    In one form of embodiment the tracking device comprises a roller unit, which is designed so as to wind up or unwind, and/or redirect, a traction element. The roller unit is advantageously arranged and attached to the post. It can however also be arranged or attached near the post, that is to say, separated from the latter. 
         [0018]    The ratio of the radius of the roller unit to the radius of the guide element is advantageously dimensioned or coordinated such that sensitive, finely graduated or smooth rotating, i.e., pivoting, of the cradle unit is possible. As already indicated, the roller unit can serve the purpose of both redirecting the traction element and also winding up or unwinding the traction element. In the last cited case, in particular, the ratio of the radius of the roller unit to the radius of the guide element can with advantage be used to set a certain transmission ratio, which enables an extremely sensitive and delicate pivoting of the tracking device. 
         [0019]    The roller unit is advantageously arranged relative to the guide element, such that a traction element runs essentially horizontally between the guide element and the roller unit. The roller unit, in particular a roller unit that is used for purposes of redirecting the traction element, can also advantageously be used so as to guide the traction element at a short distance above the ground. With regard to the reset of the traction element, together with the guidance of the cable in general, reference, however, should be made to the following statements concerning the transverse row, the longitudinal row, and the solar module field. 
         [0020]    In accordance with the invention, a transverse row of tracking devices comprises at least two inventive tracking devices, wherein the at least two tracking devices are arranged along a transverse axis, which extends transverse to the axis of rotation, and wherein the at least two tracking devices are connected by means of a traction element, such that a rotation of the one tracking device can be transferred onto the other. This means that tracking devices arranged along the transverse axis are, so to speak, mutually connected with traction elements, wherein the traction elements are arranged on the force introduction regions of the tracking devices arranged next to one another such that a traction element, which, for example, is connected to a cradle unit, that is to say, with its force introduction region, which is pivoting in the anticlockwise sense, is connected to the force introduction region of another tracking device such that the second cradle unit is pivoted by means of the traction element in the clockwise sense. A traction element is therefore pivoted by means of the pivoting movement of one cradle unit, and can thus likewise pivot another cradle unit. In this manner a rotation or a pivoting movement can easily be transferred from one tracking device to another. Here the other tracking device does not have to be arranged directly next to the first tracking device. Tracking devices that are arranged next to one another are always preferably connected by means of a traction element. By the same token, however, the next-but-one, and/or the next-but-two tracking device, etc., can also be connected in this manner. In the same manner a tracking device can also be connected with a plurality of tracking devices, in that, for example, the traction element is appropriately split over a plurality of tracking devices, or in that the one tracking device is directly connected with a plurality of traction elements. The traction elements, which transfer the rotational movement from one tracking device to others, are also called transfer elements. However, there is also always at least one traction element or, stated more generally, at least one drive force, which can pivot at least one tracking device in the transverse row, which, that is to say, introduces the pivoting movements (in both directions) into the transverse row. A traction element, which introduces this force in the present instance is called a drive element. Such a drive element can, for example, be connected with the above-cited roller unit, e.g., can be wound onto or unwound from the latter. 
         [0021]    The roller unit can take the form of a continuous torsion tube, which is designed so as to drive a plurality of transverse rows and which extends accordingly along the transverse row. However, each transverse row can also have its own such roller unit. Such a roller unit, which operates with a drive element, is designed so as to build up a tension force and in this manner enables a rotation in one direction. A transverse row therefore advantageously has two such roller units at its two ends, as a result of which pivoting movements in the clockwise sense and the anticlockwise sense are enabled. In one preferred form of embodiment the two roller units are held in synchronicity by means of an appropriately designed controller. The traction elements are advantageously held in tension with respect to the above-cited tension units. The (cable) tension can be monitored and regulated by means of load cells in the traction elements. However, operation can also take place with one drive element, which then is simply redirected at one end of the transverse row. 
         [0022]    At least one tracking device is advantageously connected with a drive unit. The drive unit can take the form of a cable winch, a spindle motor, or a hydraulic ram. A guide element, since it does in fact have the circular segment-shaped form, can itself also advantageously be used for purposes of force introduction, if it is, for example, provided with an appropriate profile, for example a toothed profile. In this case such a guide element can be driven by means of an appropriately configured gear wheel, which is, for example, connected to an electric motor. The above-cited torsion tube is designed so as to transfer a rotational movement of the drive unit onto a plurality of transverse rows. 
         [0023]    In accordance with the invention a longitudinal row of tracking devices comprises at least two inventive tracking devices, wherein the at least two tracking devices are arranged along a longitudinal axis, which extends along the axis of rotation, and wherein a rotation of the one tracking device can be transferred onto the other by means of the cradle unit and/or by means of a drive shaft. The torsion tube that has already been cited above can be interpreted as a drive shaft that is designed so as to transfer a rotation of the one tracking device onto the others along the longitudinal direction. By the same token, the transfer can also take place via the cradle units, i.e. the solar modules, or the solar module tables themselves. A cradle unit, which is essentially formed from a transverse beam and at least two longitudinal beams, can also be designed such that it extends over a plurality of tracking devices. The longitudinal beams of a tracking device can thereby be configured to be of a length such that they can still be arranged, i.e. attached, to a post of a tracking device; these are arranged along the axis of rotation near the above-cited tracking device. A longitudinal beam can likewise also extend over more than two tracking devices, for example, three, four, five, or more. However, for reasons of practicality, it is also preferred to cut the longitudinal beams into pieces appropriately. In other words, each tracking device does not have its own cradle unit, but rather a plurality of tracking devices build up into or form a large cradle unit, which extends along the longitudinal direction. Here the latter is advantageously embodied in a robust manner such that a rotational or pivotal movement of one cradle unit can be transferred onto the others along the longitudinal direction. 
         [0024]    In accordance with the invention a solar module field comprises at least one inventive transverse row of tracking devices, and at least one inventive longitudinal row of tracking devices, together with a drive unit. Possible drive units have already been cited above. In one preferred form of embodiment such a solar module field also comprises transverse rows, which have no tracking devices with guide elements. Thus in the final analysis these transverse rows are only pivoted in a passive manner. In this context it should be mentioned that the longitudinal row need not be formed exclusively from tracking devices that have the guide element. In the final analysis, tracking devices that have one cradle unit that can move about a rotary joint are sufficient. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]    Further advantages and features ensue from the following description of preferred forms of embodiment of the inventive tracking device for solar modules, from the inventive transverse row of tracking devices, from the inventive longitudinal row of tracking devices, together with the inventive solar module field, with reference to the accompanying figures. Here individual features of the individual forms of embodiment can be combined with one another within the context of the invention. 
           [0026]    Here: 
           [0027]      FIG. 1   a : shows a perspective view of a preferred form of embodiment of a tracking device for solar modules; 
           [0028]      FIG. 1   b  shows a schematic diagram of a form of embodiment of an inventive tracking device for solar modules for purposes of illustrating the kinematics during the pivoting movement; 
           [0029]      FIG. 1   c : shows a schematic diagram of a form of embodiment of a tracking device of known prior art for solar modules for purposes of illustrating the kinematics during the pivoting movement; 
           [0030]      FIG. 2 : shows a side view of a form of embodiment of a tracking device for solar modules with a roller unit; 
           [0031]      FIG. 3 : shows a side view of a form of embodiment of a tracking device for solar modules for purposes of illustrating the guidance of the traction elements; 
           [0032]      FIG. 4 : shows a form of embodiment of a transverse row of tracking devices in rough country; 
           [0033]      FIG. 5   a : shows a form of embodiment of a transverse row of tracking devices for solar modules; 
           [0034]      FIG. 5   b : shows another form of embodiment of a transverse row of tracking devices for solar modules; 
           [0035]      FIG. 5   c : shows another form of embodiment of a transverse row of tracking devices for solar modules; 
           [0036]      FIG. 5   d : shows another form of embodiment of a transverse row of tracking devices for solar modules; 
           [0037]      FIG. 6 : shows a form of embodiment of a solar module field in a plan view. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]      FIG. 1   a  shows a preferred form of embodiment of a tracking device  10  in a perspective view. The tracking device  10  comprises a post  12 , to which a transverse beam  22  is indirectly attached via a rotary joint  23 . The post  12  is, for example, anchored or secured in foundations in a ground surface such as earth, and stands essentially vertically. The rotary joint  23  is not located directly on the post  12 , but rather on a headpiece arranged at the top of the post and not designated here in any further detail. Longitudinal beams  21  are attached at both ends of the transverse beam  22 . The transverse beam  22 , together with the two longitudinal beams  21 , forms a cradle unit  20 . The two longitudinal beams  21  can be embodied such that they extend over a plurality of tracking devices. In this manner a cradle unit  20  can also be implemented, which extends over a plurality of tracking devices and thereby posts. The cradle unit  20  comprises two force introduction regions  26 , to which an essentially circular segment-shaped, or semicircular-shaped, guide element  40  is attached. The guide element  40  serves in turn to guide two traction elements, which are designated with the reference symbols  14 ′ and  14 ″. The two traction elements  14 ′ and  14 ″ are, as it were, guided by means of the guide element onto the force introduction regions  26  and are attached there. Both the two longitudinal beams  21 , and also the transverse beam  22 , are formed from closed square profiles. The guide element  40  is formed from a U-profile bent into a semicircular shape. 
         [0039]      FIG. 1   b  shows a schematic diagram of a tracking device  10  in two states. In the left-hand half of the figure a cradle unit  20  of the tracking device  10  is represented in a pivoted position. Also represented is a lever arm h″, which is located between a point of rotation  23  and a force direction F. The force acts essentially at right angles to a vertical axis H of the post  12 , i.e. at right angles to the lever arm h″. With respect to the right-hand half of the figure, in which the cradle unit  20  is aligned essentially parallel to the ground, in other words, therefore, is not pivoted, it is clear to see that the lever arm h is exactly the same size as in the left-hand half of the figure, since it follows the circular path of the circular segment, at the centre point of which is located the point of rotation. 
         [0040]      FIG. 1   c  shows a schematic diagram of a tracking device, as is of known prior art. In the left-hand half of the figure is represented a cradle unit  20 , which is pivoted about a point of rotation  23 , i.e. about an axis of rotation R. Between the point of rotation  23  and a force direction F, which introduces and maintains the pivotal movement, there extends a lever arm h″ which extends essentially at right angles to the force direction F. In the right-hand half of the figure the cradle unit  20  is represented essentially parallel to the ground, in other words, therefore in a non-pivoted position. A lever arm h′, which is measured between the point of rotation  23  and the force direction F, is here significantly larger than in the pivoted state. In order to achieve the same moment in the event of a reduction in the size of the lever arm, the force, however, must be increased, so that such a reduction in the size of the lever arm, as is schematically represented in  FIG. 1 , is extremely problematical. 
         [0041]      FIG. 2  shows a side view of a form of embodiment of a tracking device  10  with a roller unit  60 . The roller unit  60  is designed so as to redirect a traction element  14 ″, which is attached to the cradle unit  20 . By the same token, however, the traction element  14 ″ could also be wound onto or unwound from the roller unit  60 . This would, in particular, be the case if the roller unit  60  also acts as a drive element, and serves to pivot the cradle unit  20 , for example, in the clockwise sense. Here a radius R 60  of the roller unit  60  and a radius R 40  of a guide element  40  can advantageously be matched to one another. As is already known, the cradle unit  20  is attached via a point of rotation  23  to a post  12 , so that a rotational or pivotal movement about an axis of rotation R is possible. A further traction element  14 ′ is guided via the guide element  40 ; this traction element is likewise attached to the cradle unit  20 . 
         [0042]      FIG. 3  shows essentially the tracking device  10  represented in  FIG. 2 . Particular attention is here directed towards a distance a of a rotary joint  23  from the ground. A radius R 40  of a guide element  40 , is advantageously designed with respect to the distance a such that the traction elements, in this case the traction elements  14 ′ and  14 ″, are guided at as short a distance as possible above the ground. This enables the traction elements to be driven over, for example by a vehicle. 
         [0043]      FIG. 4  shows a transverse row of tracking devices  10 , which extends along a transverse axis Q. It is clear to see that the transverse axis Q need not strictly take the form of a straight line, but rather that the transverse axis Q can also extend along hilly ground. The traction elements in this case the traction elements  14 ′,  14 ″,  14 ′″, and  14 ″″ are advantageously guided by guide elements  40  of the tracking devices  10  such that their position and location is ideally matched to the ground conditions. 
         [0044]      FIG. 5   a  shows a form of embodiment of a transverse row of tracking devices  10 , which extends along a transverse axis Q, in a side view. The transverse row comprises two roller units  60 , which are designed as drive units  80 . Drive elements  16 ″ lead from the drive units  80  to cradle units  20  of the tracking devices  10  arranged next to one another. The two drive elements  16 ′ and  16 ″ are guided by means of the appropriate guide elements  40  onto the force introduction regions, which are not designated or identified here in any further detail. In general the drive elements  16 ′ and  16 ″ can take the form, for example, of wire cables. The two outer tracking devices, that is to say, their cradle units  20 , are connected in each case by means of a traction element  14 ′ and  14 ″ respectively with the central cradle unit  20 . This arrangement of the traction elements enables a rotation of the one tracking device  10  to be transferred onto the other tracking device  10 . The introduction of the movement into the transverse row takes place by means of the two drive units  80 , wherein the left-hand drive unit  80  introduces a rotation in the clockwise sense, while the right-hand drive unit  80  introduces a rotation in the anticlockwise sense. Here the drive units  80  and roller units  60  are in each case embodied as one component. 
         [0045]      FIG. 5   b  shows the configuration of a transverse row of tracking devices  10  essentially as represented in  FIG. 5   a . Here a roller unit  60  serves the purpose of redirecting a drive element  16 ′, e.g. a wire cable  16 ′, and guiding it to a drive unit  80 . From the drive unit  80  a second drive element  16 ″, e.g. a wire cable  16 ″, leads to a tracking device  10  arranged on the right in  FIG. 5   b . In actual fact, however, the drive unit  80  could also be designed such that, for example, it also redirects the drive element  16 ′ and guides it to the right-hand tracking device  10 , so that this configuration could manage with only one drive element. The runs of the other traction elements  14 ′,  14 ″ correspond to those in the configuration represented in  FIG. 5   a.    
         [0046]      FIG. 5   c  shows a configuration of a transverse row of tracking devices  10 , which operates with only one drive element  16  and two roller units  60 . One drive unit  80  is provided for purposes of moving or relocating the drive element  16 ; this is designed as a spindle motor or a hydraulic ram. 
         [0047]      FIG. 5   d  shows a form of embodiment of a transverse row of tracking devices, wherein a drive unit  80  is designed as a gear wheel, or comprises a gear wheel, which can engage in a corresponding geometry that is arranged a guide element  40  of a tracking device  10 . The transfer of this movement takes place by means of traction elements  14 ′,  14 ″, and  14 ′″, acting as transfer elements. The transfer element  14 ′″ is appropriately redirected by means of two roller units  60 . 
         [0048]    Needless to say, the transverse rows for tracking devices shown in  FIGS. 5   a  to  5   d  are not limited to the arrangement/use of just three tracking devices. Advantageously more than three tracking devices  10  are arranged in a transverse row, which extends along a transverse axis Q. 
         [0049]      FIG. 6  shows a solar module field in a plan view, which comprises a multiplicity of transverse rows, which extend along a transverse axis Q, together with a multiplicity of longitudinal rows, which extend along a longitudinal axis L. It is indicated by dashed lines that solar modules, or solar module tables  24 , extend along the longitudinal axis L, which are supported by means of the appropriate tracking devices  10 , that is to say, by their cradle units. It is clear to see that there are also transverse rows of tracking devices, which are not provided with a guide element  40 . A pivoting movement of these transverse rows takes place via the appropriately designed cradle units  20 , that is to say, via the solar module tables  24 . It is therefore not necessary to populate the whole of the solar module field with tracking devices that have the circular segment-shaped guide element. In the solar module field represented here roller units  60  are connected with driveshafts  82  at the ends of the appropriate transverse rows. A rotational movement is introduced into the driveshafts  82  by means of drive units  80 , which movement can in the final analysis be transferred by means of the roller units  60  onto the appropriate drive elements  60  and the appropriate traction elements, for example,  14 ′,  14 ″,  14 ′″, and  14 ″″. 
       LIST OF REFERENCE SYMBOLS 
       [0000]    
       
           10  Tracking device 
           12  Post 
           14  Traction element, transfer element 
           16  Traction element, drive element 
           20  Cradle unit 
           21  Longitudinal beam 
           22  Transverse beam 
           23  Rotary joint 
           24  Solar module/solar module table 
           26  Force introduction region 
           40  Guide element 
         R 40  Radius of guide element 
           60  Roller unit 
         R 60  Radius of roller unit 
           80  Drive unit 
           82  Drive shaft 
         a Distance of the rotary joint from the ground surface 
         Q Transverse axis 
         L Longitudinal axis 
         R Axis of rotation 
         H Vertical axis 
         h, h′, h″ Lever arm