ES2950742A2 - Solar tracker with improved damping - Google Patents

Abstract

A solar panel installation assembly comprises a stationary structural element that extends longitudinally to an end of the distal element. A rotary shaft, including a rotary shaft, rotatably connected to the stationary structural member at the distal end. An arm is attached to the rotating shaft and aligned with the stationary structural member along the rotating axis. An impact absorber includes a first and a second longitudinal end, the first rotatably connected to the arm and the second rotatably connected to the stationary structural member. The impact absorber comprises a shaft of variable length including an outer tube and a coaxial inner tube, and inner and outer springs, coaxial with the outer tube, where the outer and inner springs are respectively radially adjacent to a radially outer side of the tube. interior and to a radially interior side of the inner tube.

Description

DESCRIPTION

Solar tracker with improved damping

Background of the invention

1. Technical field

The present disclosure relates generally to a solar panel installation and, more particularly, to apparatus and assemblies for use in a solar panel installation.

2. Background information

Single-axis trackers are now relatively common in the solar industry. Solar trackers must be designed to withstand the applicable loads: self-weight (dead load), snow, wind, earthquake, etc. according to local building codes. However, the vast majority of the time, the only significant load comes from its own weight. Since the center of gravity is horizontally displaced from the center of rotation of the follower table for any panel tilt angle other than flat, a self-weight torque is applied to the follower row tube for most angles. of follower inclination. Depending on the weight of the supported solar modules and the distance between the center of gravity of the modules and the center of rotation of the tube, this self-weight torque may be significant enough to cause significant rotational deflection of the row tube. Since the purpose of a single-axis solar tracker is to rotate the solar modules so that they are always perpendicular to the beam of light coming from the sun (often called tracking precision), this rotation due to self-weight can have a significant impact in that perpendicularity and, therefore, in the energy production and income of the solar tracker. There is a need to improve the assembly of a solar panel installation.

Disclosure Summary

According to one aspect of the disclosure, an assembly for a solar panel installation comprises a stationary structural member having a length extending longitudinally to a distal member end; a rotating shaft having a rotating shaft, wherein the rotating shaft is rotatably connected to the member stationary structural at the end of distal limb; an arm secured to the rotating shaft and aligned with the stationary structural member along the rotational axis; and an impact absorber having a first longitudinal end and a second longitudinal end, the first longitudinal end being rotatably connected to the arm and the second longitudinal end being rotatably connected to the stationary structural member, wherein the impact absorber comprises a variable length shaft including an outer tube and a coaxial inner tube, and a spring coaxial with the inner and outer tubes, where the spring is radially adjacent to an outer side wall of the inner tube and axially positioned between a flange of the outer tube and a radial projection extending from the inner tube.

The outer tube may include a first stop fixed to an inner surface of the outer tube and includes a through hole coaxial with the inner tube, and a radial projection that extends from the inner tube and is fixed thereto, such that the first stop and the radial projection limit the movement of the inner tube within the outer tube.

The assembly may include an actuator pivotally connected to the arm and pivotally connected between the first and second flanges of the stationary structural member and a web extending between the first and second flanges, wherein a portion of the actuator protrudes through of an opening in the network, and wherein the actuator is configured to change its length in order to move the arm with respect to the stationary structural member and, therefore, rotate the rotary shaft about the rotational axis.

The rotating shaft may be generally perpendicular to the stationary structural member.

The stationary structural member may be configured to be securely anchored to the ground.

According to another aspect of the disclosure, an assembly for a solar panel installation comprises a plurality of stationary structural members each having a length extending longitudinally to an associated distal member end; a rotary shaft having a rotary shaft and a rotary shaft length L extending from a first end to a second end, wherein the rotary shaft is rotatably connected to the plurality of stationary structural members at the ends distal limb; a first drive mechanism configured to rotate the rotary shaft about the rotary axis in a first of the plurality of members stationary structural members, the first drive mechanism mounted to the first of the stationary structural members; and an impact absorber comprising a shock absorber and a coaxial spring connected between the first of the stationary members and the rotating shaft.

The shock absorber may comprise a shaft of variable length including an outer tube and a coaxial inner tube, and the coaxial spring is radially adjacent to an outer side wall of the inner tube and axially positioned between a flange of the outer tube and a radial projection. extending from the inner tube.

According to yet another aspect of the disclosure, an assembly for a solar panel installation comprises a stationary structural member having a length extending longitudinally to the end of the distal member; a rotating shaft having a rotating shaft, wherein the rotating shaft is rotatably connected to the stationary structural member at the end of the distal member; an arm secured to the rotating shaft and aligned with the stationary structural member along the rotational axis; and an impact absorber having a first longitudinal end and a second longitudinal end, the first longitudinal end being rotatably connected to the arm and the second longitudinal end being rotatably connected to the stationary structural member, wherein the impact absorber comprises a variable length shaft including an outer tube and a coaxial inner tube, and inner and outer springs coaxial with the outer tube, where the outer spring is radially adjacent to a radially outer side of the inner tube and the inner spring is radially adjacent to a radially inner side of the inner tube.

The inner spring can resist the extension of the inner tube from the outer tube.

The outer spring may have an outer spring travel length and the inner spring an inner spring travel length, and the outer spring travel length is at least twice the inner spring travel length.

The outer spring may have an outer spring travel length and the inner spring an inner spring travel length, and the outer spring travel length is at least four times the inner spring travel length.

The outer spring may have an outer spring travel length and the inner spring an inner spring travel length, and the outer spring travel length is at least five times the inner spring travel length.

The inner spring can be positioned to add resistance towards the end of the travel of the outer spring in extension.

The travel length of the outer spring and the travel length of the inner spring can be asymmetric in travel length for spring compression.

The inner spring may be engaged to resist extension of the inner tube from the outer tube in approximately the last three inches of extension travel of the inner tube from the outer tube.

The inner spring may not resist the compression of the outer spring.

The foregoing characteristics and operation of the invention will become more evident in light of the following description and the accompanying drawings.

Brief description of the drawings

Figure 1 illustrates a solar panel installation;

Figure 2 illustrates a first embodiment of a stationary structural member;

Figure 3 illustrates a second embodiment of a stationary structural member;

Figures 4 and 5 illustrate an exemplary embodiment of a rotating shaft;

Figure 6 illustrates adjacent segments coupled together with a coupler;

Figure 7 illustrates a bearing assembly configured to rotatably mount the rotating shaft;

Figure 8 illustrates two adjacent bearing assemblies configured to rotatably mount the rotating shaft;

Figure 9 illustrates an exploded view of one embodiment of a bearing assembly;

Figure 10 illustrates an exploded view of the first and second segments of a bearing wheel of the bearing assembly;

Figures 11-13 illustrate a bearing assembly with a single, integral (one-piece) collar base;

Figure 14 illustrates an exemplary embodiment of a drive mechanism;

Figure 15 is an alternative embodiment drive system utilizing a linear actuator including a motor that extends/retracts to rotate the rotary shaft;

Figure 16 illustrates an exemplary embodiment of a windbreak plate and support members operably positioned on the rotating shaft;

Figure 17 illustrates an exemplary embodiment of a windbreak plate, support members and a solar panel operably positioned on the rotating shaft;

Figures 18 and 19 illustrate an exemplary embodiment of a node controller with the rotating shaft;

Figure 20 illustrates a bearing assembly operably connected to the rotating shaft and structural member and including one or more lateral capture devices;

Figure 21 illustrates a portion of a drive structure of an alternative embodiment that includes a damper;

Figure 22 illustrates a portion of yet another drive structure of an alternative embodiment including a first damper and a second damper;

Figure 23 is the first perspective view of yet another drive structure including solar tracker rotation stops;

Figure 24 is a second perspective view of the still other drive structure of Figure 23 that includes the rotation stops of the solar tracker;

Figure 25 illustrates a variable length shaft that may include a plurality of tubes that are telescopically inserted into each other and include rotation stops that correspond to the maximum range of movement of the follower;

Figure 26 illustrates an alternative embodiment variable length shaft that may include a plurality of tubes that are telescopically inserted into each other and include a rotation stop that corresponds to the maximum range of movement for the spring-loaded follower;

Figure 27 is a simplified illustration of yet another embodiment of an impact absorber and including a first spring for resisting retraction and a second spring for resisting extension of the impact absorber;

Figures 28A, 28B and 28c are simplified cross-sectional illustrations of the impact absorber of Figure 27 in various states of extension/compression;

Figures 29A, 29B and 29c are pictorial illustrations of the impact absorber of Figure 27 in various states of extension/compression;

Figure 30 is a simplified cross-sectional illustration of yet another embodiment of a double tube impact absorber that includes a spring that resists both retraction and extension;

Figures 31A, 31B and 31C are simplified cross-sectional illustrations of the impact absorber of Figure 30 in various states of extension/compression;

Figure 32 is a simplified cross-sectional illustration of yet another embodiment of a double-tube impact absorber including coaxial outer and inner springs with asymmetrical travel length; and

Figures 33A, 33B and 33C are simplified cross-sectional illustrations of the impact absorber of Figure 32 in various states of extension/compression.

Detailed description

Figure 1 illustrates a solar panel installation 10 that includes one or more solar panel arrays 12 14. Each of these solar panel arrays 12-14 includes one or more solar panels 15-18 (e.g., a linear array of solar panels) mounted on a rack structure 20. Each shelving structure 20 includes a plurality of stationary structural members 22, 24, a rotating shaft 26, a plurality of bearing assemblies 28, 30 (see Figure 5), and at least one drive mechanism 32. Each shelving structure 20 may also include at least one windbreak panel 34 to be configured with the drive mechanism 32.

Figures 2 and 3 respectively illustrate exemplary embodiments of the stationary structural members 22, 24. The stationary structural member of Figure 2 is configured as a center post, or drive mechanism support post. The stationary structural member of Figure 3 is configured as a standard post, or support post. In some embodiments, one or more of the stationary structural members may be securely anchored to the ground. For example, a lower portion of the length of the member may be buried in the ground and/or otherwise secured to or with a foundation, which may be a driven pile, helical screw, screw, pre-cast or cast-in foundation. site (for example, the Pourin-Place™ installation system available from GameChange Solar Corp.) or any other type of foundation. In other embodiments, one or more of the stationary structural members may be anchored to another structure such as, but not limited to, the roof of a building.

Still referring to Figures 2 and 3, each stationary structural member has a length. This length extends longitudinally (e.g., substantially vertically when installed) from its lower portion to a distal (e.g., upper) member end 37, 39. Each stationary structural member may include one or more flanges 38-41 and a central web 42, 43, which extends laterally (e.g., horizontally when installed) between the respective first and second flanges. Each of the flanges 38, 39 of Figure 2 includes one or more mounting openings such as, but not limited to, a pair of longitudinal slots 46, 47. The web 43 of Figure 3 similarly includes one or more mounting openings such as, but not limited to, a pair of longitudinal slots 50, 51.

Figures 4 and 5 illustrate an exemplary embodiment of the rotary shaft 26. The rotary shaft has a length, which extends axially (e.g., substantially horizontally when installed) along a rotational axis 54. The rotating shaft may be configured as a single length of shaft as shown in Figure 5. Alternatively, as shown in Figure 6, the rotating shaft 26 may be configured with a plurality of shaft segments 56, 57, where adjacent segments are coupled together with a coupler 60 (e.g., a clamping sleeve) and/or otherwise connected to each other. The exemplary rotating shaft of Figure 4 has a polygonal (e.g., square) cross-sectional geometry; However, the rotary shaft of the present disclosure is not limited to such a geometry.

Referring to Figures 5, 7 and 8, the bearing assemblies 28-30 are configured to rotatably mount the rotating shaft 26 to the stationary structural members 22. Now referring to Figure 9, each bearing assembly may include a bearing wheel 64, a bearing collar 66 and one or more capture rings 68-69.

Referring to Figures 9, the bearing wheel 64 has a rotational axis, which is coaxial with the rotational axis 54 of the rotary shaft 26 (see Figure 5). The bearing wheel 64 includes and extends radially between an inner surface 72 and an outer surface 74. The inner surface 72 forms, at least partially, a hole. This hole extends axially through the bearing wheel 64 along the rotational axis 54. The hole may have a polygonal (e.g., square) cross-sectional geometry configured complementary to the geometry of the rotating shaft. In this way, the hole can receive the rotating shaft axially therethrough. Of course, in other embodiments, the hole may be slightly larger than the rotary shaft 26 and/or have a different geometry than the rotary shaft where, for example, an intermediate element such as a bushing or sleeve is disposed between the bearing wheel and shaft. The outer surface 74 may have a circular cross-sectional geometry.

The bearing wheel 64 may be formed as a single, integral body, as shown in Figures 11-13. Alternatively, the bearing wheel may be formed from a plurality of discrete segments (e.g., discretely formed halves) as shown in Figures 9 and 10. These segments may be connected to each other or not (e.g., simply supported against each other).

Again referring to Figure 9, the bearing collar 66 may include a collar base 76 and a collar mount 78. The collar base 76 includes an inner surface 72 configured to circumscribe and slidably engage the outer surface 74 of the bearing wheel 64. This collar base 76 may be formed as a single body, integral as shown in Figures 11-13. Alternatively, the collar base 76 may be formed from a plurality of discrete segments secured together to form a hoop structure as shown in Figure 9. The segments of Figure 9, in particular, are secured together to through locking tongue and groove (mortise) joints; however, other fixing procedures and/or tools may be used to secure the segments together.

In the exemplary embodiment of Figure 9, the lower segment 80 extends approximately 30 degrees and approximately 90 degrees around the rotational axis 54. The upper segment extends approximately 330 degrees and approximately 270 degrees around the rotational axis 54. The present disclosure is, of course, not limited to the above values. For example, in other embodiments, each segment may extend approximately 180 degrees around the rotational axis 54, or otherwise.

The collar mount 78 projects radially outward (e.g., downward) from the collar base 76 (e.g., the lower segment) to a distal mount end 82. The collar mount 78 may be formed integrally with the collar base 76 (e.g., the lower segment), or secured thereto. The collar mount 78 includes a plurality of mounting openings 84, 85 in the distal mount end 82. Each of these mounting openings 84, 85 extends axially through the collar mount 78. The mounting openings 84, 85 are configured to respectively receive fasteners 88, 89 (e.g., bolts or otherwise) to secure the collar mount 78 to a respective one of the stationary structural members 22, 24 as shown in the Figures 7 and 8. In particular, each fastener extends through a respective one of the mounting openings in the collar mount and a respective one of the mounting openings 84, 85 (e.g., slots) in the structural member 22, 24 stationary. The fasteners may be positioned within mounting openings (e.g., slots) in the stationary structural member so as to adjust the vertical height or lateral position of the bearing assembly; for example, in order to ensure that the rotating shaft is as straight and/or level as possible as the rotating shaft passes through the bearing assemblies. The fasteners can then be tightened to secure the collar mount 78 to the respective stationary structural member 22, 24.

Capture rings 68, 58 are secured to opposite axial sides of collar base 76 using, for example, one or more fasteners (e.g., screws) 88-93. Each capture ring 68, 69 projects radially inward from the surface 78 interior of the collar base 76 and therefore overlaps an axial end of the bearing ring 66 to prevent the end from sliding out of the hole of the collar base.

Figure 14 illustrates an exemplary embodiment of the drive mechanism 32. This drive mechanism includes a drive arm 98 and an actuator 100. The drive arm 98 is substantially axially aligned with the stationary structural member 22 along the rotational axis. A first end of the drive arm is secured to the rotating shaft 26. The distal end flanges of the drive arm 98, for example, are clamped around the rotary shaft 26 between two adjacent and proximate bearing assemblies 28, 29.

The actuator 100 is substantially axially aligned with the stationary structural member and the actuating arm along the rotational axis. Actuator 100 is pivotally connected to drive arm 98. More particularly, a first end of the actuator projects through an opening in the drive arm and is pivotally connected to and between two sides of the drive arm at its second end by a shaft; for example, a threaded rod 102. The actuator is also connected to the stationary structural member 22; for example, the center post. More particularly, an intermediate portion of the actuator 100 pivotally connected to and between the first and second flanges 38, 39 of the stationary structural member 22. An end portion of the actuator 100 may project through an opening in the web of the stationary structural member to a second end of the actuator, where a motor 104 may be located to drive the actuator. The intermediate portion of the actuator may be connected to the flanges 38, 39 by an actuator mount 106 secured around it, or with trunnion blocks welded to the actuator housing, and a shaft.

Figure 15 is an alternative embodiment drive system that uses a linear actuator 99 that includes a motor 101 that extends/retracts to rotate the rotary shaft 26.

The actuator 100 may be, for example, a hydraulic piston actuator or a screw drive actuator. Therefore, the actuator may include a push rod 107 and a base 108, where the push rod 107 protrudes from and slides in and relative to the base. The push rod 107 may be pivotally connected to the drive arm 98. The base 108 may be pivotally connected to the stationary structural member 22. Of course, the drive mechanism of this Disclosure is not limited to the above exemplary actuator configuration or mounting scheme.

Figures 16 and 17 illustrate an exemplary embodiment of the windbreak plate 34. This windbreak plate 34 is mounted on the rotating shaft 26. In particular, the windbreak plate of Figures 16 and 17 is mounted on a pair of support members 110, 112 (e.g., straps), which in turn are mounted on the rotating shaft 26. The support members are located on opposite sides of the stationary structural member 22 and/or two respective bearing assemblies 28, 29 along the rotational axis. The windbreak plate 34 is configured to at least partially cover the distal member end of the stationary structural member and the drive mechanism. The windbreak plate may also provide a mounting surface for a solar panel 114, which is operable to provide power to the drive mechanism 32. The solar panel 114 may be nested with an opening 116 in the windbreak plate 34 on the end of the distal member.

An exemplary embodiment of a node controller 118 is shown with rotating shaft 26 in Figures 18 and 19. This node controller 118 may include a processor, a tilt measurement device (e.g., a sensor), a clock, a memory, one or more motor drives, and a communication device (for example, a transceiver, an input port and/or an output port). The tilt measuring device is configured to measure the tilt of the solar panels, which can be measured directly or indirectly through the rotational position of the rotating shaft 26. The processor includes executable programs to determine what tilt the solar panel array should be positioned at a given time of day based on one or more of the following parameters: location; sun elevation and/or azimuth; row spacing; and slope for rollback analysis. The motor drives are configured to command the actuator motor to rotate and actuate the actuator until a proper tilt of the solar panel is obtained. The communication device is configured to provide communication between the node controller and another device; for example, the master controller.

Figure 20 illustrates a bearing assembly operably connected to the rotating shaft and structural member and including one or more lateral capture devices

Figure 21 illustrates a portion of an alternative embodiment drive structure 300 that includes a damper 302. As shown in Figure 21 a bearing assembly 304 secures the rotary shaft/row tube 306, which is connected to an arm 308. The shock absorber 302 may include a shock absorber having a piston and a piston rod and a cooperating spring 310. A first end 312 of the shock absorber is connected to the arm 308 while a second end 314 of the shock absorber is connected to a post 316. The shock absorber and spring prevent the follower from excessively rotating and moving too far forward and backward. back, allowing the followers to be longer and handle higher wind speeds.

Figure 22 illustrates a portion of yet another alternative embodiment drive structure 340 that includes a first shock absorber 302 and a second shock absorber 342. The bearing assembly 304 fixes the rotary shaft 306, which is connected to an arm 344. The shock absorber 302 is connected to a first end of the arm 344, and the second shock absorber 342 is connected to a second end of the arm 344. This embodiment also prevents excessive rotation and increases the stability of the follower in high winds.

Figure 23 is a first perspective view of another drive structure 346 that includes the solar tracker rotation stops and Figure 24 is a second perspective view of yet another drive structure 346 of Figure 23 that includes the rotation stops. rotation of the solar tracker. The drive structure 346 can be used with a single-axis solar tracker and includes a variable length shaft 347 with mechanical stops. The variable length shaft 347 may include a plurality of tubes (e.g., two tubes 347a, 347b) that are telescopically inserted into each other.

The variable length shaft 347 is installed between a single axis follower post 348 and an arm 349 extending from the rotary axis/row tube 350, perpendicular thereto. Both the arm 349 and the variable length shaft 347 are in a plane perpendicular to the longitudinal axis of the row tube.

Figure 25 illustrates an embodiment of the variable length shaft 347 that may include the plurality of tubes 347a, 347b that are telescopically inserted into one another and include stops/bumpers that correspond to the maximum range of movement for the follower. In this exemplary embodiment, a first bumper (e.g., an elastomeric material) 353 with a central through hole coaxial with the tubes 347a, 347b may be attached to the inner diameter of the outer tube 347a. The inner tube 347b may include a coaxial projection 354 that limits the amount of displacement of the inner tube 347b from the outer tube 347a when the projection 354 abuts the first bumper 353. The first bumper 353 is preferably an elastomer (e.g. rubber) to provide vibration and impact isolation when the projection 354 reaches the first bumper 353. Similarly, a second bumper 355 may be located at a second location within and attached to the outer tube 347a to act as a stop and prevent the inner tube 347b from retracting. too much, and dampen vibration and impact when the variable length shaft 347 is fully retracted.

The stops/bumpers 353, 355 can be positioned based on the maximum travel range. That is, the stops 354, 355 on the variable length shaft 347 correspond to the shaft length when the single-axis tracker is at its maximum eastward and westward rotation angle. In other words, the tree 347 will become a structural support that carries some of the self-weight torque. In this way, the tracker table will not exceed the maximum design inclination towards east or west and the tracking accuracy of the system will reach the desired level. Rubber stops, alone or in combination with springs or shock absorbers, prevent a "hard stop" from occurring when the variable length shaft reaches an end of travel and therefore prevent an impact type load from being applied to the solar photovoltaic modules in the single axis tracker.

As shown in the alternative embodiment 380 of Figure 26, it is contemplated that a spring 378 can be installed in the joint (s) between the telescopic tubes 347a, 347b portions of the shaft 347 of variable length, and coaxial with the tubes, to avoid impact loading when the mechanical stop length is reached.

A damper may be part of variable length shaft 347. This will improve the damping and other harmonic properties of the follower table. This will result in higher critical wind speeds for aeroelastic stability, allowing the tracker to track the sun at higher wind speeds and therefore increasing the energy production and revenue of the tracker system.

Referring to Figures 23-26, eyelets 351, 352 are installed at each end of the variable length shaft 347. These provide a quick and cost effective mechanism for attaching the variable length shaft 347 to the single axis follower frame via a bolted connection.

Figure 27 is a simplified cross-sectional illustration of yet another embodiment of an impact absorber 500 (e.g., a shock absorber and a spring) that includes an outer spring 502 to resist retraction and an inner spring 504 to resist extension of a shock absorber 506 that includes an internal piston. The impact absorber 500 may be, for example, a single-tube or twin-tube design (i.e., a double tube), or any other known configuration. Figure 27 illustrates a monotube tube design.

In one embodiment the impact absorber 500 includes an outer shell 508 and an inner shell 510 that is nested within and coaxial with respect to the outer shell 508. The housings 508, 510 may be cylindrical or have any other shape in cross section. The impact absorber also includes eyelets 351, 352 that are installed on either axial end of the impact absorber as shown in Figure 27. These provide a quick and cost-effective mechanism for attaching the impact absorber 500 to the follower structure through of a bolted connection. A piston 507 also includes an orifice plate and is slidably disposed in the inner casing 510 to allow hydraulic oil to move between a first chamber 511 and a second chamber 513.

The outer spring 502 is coaxial with respect to the housings 508, 510 and radially adjacent to a radially outer side of the inner housing 510. The outer spring 502 resists retraction of the inner casing 510 into the outer casing 508. A first end 516 of the outer spring 502 may be attached to a first washer/flange 518, which extends radially from and is attached to the inner housing 510. A second end 520 of the outer spring 502 may abut (e.g., axially) against a flange 522 that extends radially from the outer casing 508 and is secured thereto. The second end 520 of the outer spring 508 may or may not be attached to the flange 522.

The inner spring 504 is coaxial with respect to the housings 508, 510 and radially adjacent to a radially inner side of the inner housing 510. The inner spring 504 resists the extension of the inner shell 510 from the outer shell 508. The inner spring 504 may be attached at its distal end 524 to a stroke end of the inner housing 510. A proximal end 526 of the inner spring 524 may axially abut against a projection 528.

Figure 28A is a simplified cross-sectional illustration of the impact absorber 500 of Figure 27 in a compressed position. In the present embodiment, the outer spring 502 is compressed and the inner spring 504 is under tension.

Figure 28B is a simplified cross-sectional illustration of the impact absorber 500 of Figure 27 in a neutral position in which the inner and outer springs 502, 504 are both in uncompressed positions.

Figure 28C is a simplified cross-sectional illustration of the impact absorber 500 of Figure 27 in an extended position. In the present embodiment, the outer spring 502 is under tension and the inner spring 504 is compressed. In this position, the inner spring resists extension.

The impact absorber of Figures 27, 28A, 28B and 28C may include one or more of the rotation stop features (e.g., 353, 355) as illustrated in Figure 25.

Figures 29A, 29B and 29c are pictorial illustrations of the impact absorber of Figure 27 in various states of extension/compression.

Figure 30 is a simplified cross-sectional illustration of a dual-tube impact absorber 600 (e.g., a shock absorber and a spring) that includes a spring 602 that resists both retraction and extension. The present embodiment includes a piston 604 (e.g., steel plate piston with a hole), and an inner casing 606 nested within and coaxial with respect to an outer casing 608. The housings 606, 608 may be cylindrical or have any other shape in cross section. The impact absorber 600 also includes eyelets 610, 612 installed at either axial end of the impact absorber as shown in Figure 30. The piston 604 includes an orifice plate that is slidably disposed in the inner casing 606, which allows hydraulic oil to move between the first and second chambers 609, 611. As a double tube configuration, the impact absorber 600 includes a radial gap 615 that forms a compensation chamber between the inner shell 606 and a coaxially extending side wall 613 located radially inward with respect to the inner shell. The compensation chamber is partially filled with gas (e.g., nitrogen) and partially with buffer oil, which moves between the compensation chamber and the first chamber in a known manner. A valve located within the inner housing 606 allows the flow of damping fluid between the chamber 609 and the compensation chamber/radial gap 615 in response to the movement of the piston.

Still referring to Figure 30, a first end 620 of the spring 602 may be attached to a first washer/flange 622, which extends radially from the housing 510. inside and is fixed to it. A second end 624 of the spring may abut (e.g., axially) a radially extending flange 626 and is secured thereto. The embodiment of Figure 30 includes a single spring, but it is contemplated that the double tube embodiment illustrated in Figure 30 may be configured for two springs as illustrated in Figure 27.

Figures 31A, 31B and 31C are simplified cross-sectional illustrations of the impact absorber of Figure 30 in various states of extension/compression.

Figure 32 is a simplified cross-sectional illustration of yet another embodiment of a twin-tube impact absorber 700 that includes coaxial outer and inner springs 702, 704 with asymmetrical travel lengths. The outer spring 702 resists both retraction and extension. The inner 704 spring resists extension. The present embodiment includes a piston 706 (e.g., steel plate piston with a hole), and an inner casing 606 nested within and coaxial with respect to an outer casing 608. The housings 708, 710 may be cylindrical or have any other shape in cross section. The impact absorber 700 also includes eyelets 712, 714 installed at either axial end of the impact absorber as shown in Figure 32. The piston 706 includes an orifice plate that is slidably disposed in the inner casing 606, which allows hydraulic oil to move between the first and second chambers 716, 718. As a double tube configuration, the impact absorber 600 includes a radial gap 615 that forms a compensation chamber between the inner shell 606 and a coaxially extending side wall 722 located radially inward with respect to the inner shell. The compensation chamber is partially filled with gas (e.g., nitrogen) and partially with buffer oil, which moves between the compensation chamber and the first chamber in a known manner. A valve located within the inner casing allows flow of damping fluid between chamber 716 and compensation chamber/radial gap 722 in response to movement of the piston. The outer spring 702 may be connected to the outer casing 710 at a first axial end through a flange/cap surface 724. At a second axial end, the outer spring 702 may be connected to the inner tube 708 through a washer 726 that coaxially surrounds and is secured to the inner tube 708.

The outer spring 702 is configured and sized to resist both retraction and extension. The inner spring 704 is configured and sized to resist extension.

Figures 33A, 33B and 33C are simplified cross-sectional illustrations of the impact absorber of Figure 32 in various states of extension/compression. Figure 33A illustrates the impact absorber 700 fully extended. In this position, the outer spring 702 is fully extended, while the inner spring 704 is fully compressed. Figure 33B illustrates the impact absorber 700 positioned such that the outer spring 702 is in its relaxed/uncompressed state. The inner spring is relaxed and unengaged at this point, as the inner spring must add resistance to the capacity of the extended outer spring. Figure 33C illustrates the impact absorber 700 positioned such that the outer spring 702 is in its fully compressed state. Once again, the inner spring remains unengaged and relaxed, as the piston has moved to the opposite extreme position, away from the inner spring.

In an exemplary embodiment, the outer spring 702 may have approximately 13 inches of travel from its relaxed length (Figure 33B) to its fully compressed length (Figure 33C). In the present exemplary embodiment the inner spring 704 may have approximately 2.5 inches of travel from its relaxed length (Figure 33B) to its fully compressed length (Figure 33A). Engagement of the inner spring occurs with the outer spring partially extended, so while Figure 33B shows the inner spring in its relaxed state, compression will not begin until there is approximately 2.5 inches of travel remaining to extend on the stroke. .

While various embodiments of the present invention have been disclosed, it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the invention. For example, the present invention, as described herein, includes various aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present invention that some or all of these features may be combined with any one of the aspects and remain within the scope of the invention. Accordingly, the present invention should not be restricted except in light of the appended claims and their equivalents.

Claims (16)

1. A set for an installation of solar panels, the set comprising: a stationary structural member having a length extending longitudinally to a distal member end; a rotating shaft having a rotating shaft, wherein the rotating shaft is rotatably connected to the stationary structural member at the end of the distal member; an arm secured to the rotating shaft and aligned with the stationary structural member along the rotational axis; and an impact absorber having a first longitudinal end and a second longitudinal end, the first longitudinal end being rotatably connected to the arm and the second longitudinal end being rotatably connected to the stationary structural member, wherein the impact absorber comprises a shaft of variable length including an outer tube and a coaxial inner tube, and a spring coaxial with the inner and outer tubes, where the spring is radially adjacent to an outer side wall of the inner tube and axially positioned between a flange of the outer tube and a radial projection extending from the inner tube. 2. The assembly of claim 1, wherein the outer tube includes a first stop fixed to an inner surface of the outer tube and includes a through hole coaxial with the inner tube, and a radial projection extending from and fixed to the inner tube, such that the first stop and the radial projection limit the movement of the inner tube within the outer tube. 3. The assembly of claim 1, further comprising an actuator pivotally connected to the arm and pivotally connected between the first and second flanges of the stationary structural member and a web extending between the first and second flanges, in the wherein a portion of the actuator protrudes through an opening in the web, and wherein the actuator is configured to change its length in order to move the arm with respect to the stationary structural member and thereby rotate the rotary shaft around the rotational axis. 4. The assembly of claim 1, wherein the rotating shaft is generally perpendicular to the stationary structural member. 5. The assembly of claim 3, wherein the stationary structural member is configured to be securely anchored to the ground. 6. A set for an installation of solar panels, the set comprising: a plurality of stationary structural members, each having a length extending longitudinally to an associated distal member end; a rotary shaft having a rotary shaft and a rotary shaft length L extending from a first end to a second end, wherein the rotary shaft is rotatably connected to the plurality of stationary structural members at the ends distal limb; a first drive mechanism configured to rotate the rotary shaft about the rotary axis on a first of the plurality of stationary structural members, the first drive mechanism mounted on the first of the stationary structural members; and an impact absorber comprising a shock absorber and a coaxial spring connected between the first of the stationary members and the rotating shaft. 7. The assembly of claim 1, wherein the impact absorber comprises a shaft of variable length including an outer tube and a coaxial inner tube, and the coaxial spring is radially adjacent to an outer side wall of the inner tube and axially positioned between an outer tube flange and a radial projection extending from the inner tube. 8. A set for an installation of solar panels, the set comprising: a stationary structural member having a length extending longitudinally to a distal member end; a rotating shaft having a rotating shaft, wherein the rotating shaft is rotatably connected to the stationary structural member at the end of the distal member; an arm secured to the rotating shaft and aligned with the stationary structural member along the rotational axis; and an impact absorber having a first longitudinal end and a second longitudinal end, the first longitudinal end being rotatably connected to the arm and the second longitudinal end being rotatably connected to the stationary structural member, wherein the impact absorber comprises a shaft of variable length including an outer tube and a coaxial inner tube, and inner and outer springs coaxial with the outer tube, where the outer spring is radially adjacent to a radially outer side of the inner tube and the inner spring is radially adjacent to one side radially inside the inner tube. 9. The assembly of claim 8, wherein the inner spring resists extension of the inner tube from the outer tube. 10. The assembly of claim 8, wherein the outer spring has an outer spring travel length and the inner spring has an inner spring travel length, and the outer spring travel length is at least twice the length of internal spring displacement. 11. The assembly of claim 8, wherein the outer spring has an outer spring travel length and the inner spring has an inner spring travel length, and the outer spring travel length is at least four times the length of internal spring displacement. 12. The assembly of claim 8, wherein the outer spring has an outer spring displacement length and the inner spring has an inner spring displacement length, and the outer spring displacement length is at least five times the length of internal spring displacement. 13. The assembly of claim 10, wherein the inner spring is positioned to add resistance toward the end of the length of travel of the outer spring in extension. 14. The assembly of claim 8, wherein the outer spring travel length and the inner spring travel length are asymmetric in travel length for compression of the spring. 15. The assembly of claim 8, wherein the inner spring is coupled to resist extension of the inner tube from the outer tube in approximately the last three inches of extension displacement of the inner tube from the outer tube. 16. The assembly of claim 15, wherein the inner spring does not resist compression of the outer spring.