Coupling system for coupling curved objects to a central axis

Abstract

A coupling system for coupling a curved object to a central axis, the curved object comprising an inner surface and an outer surface, the inner surface facing the central axis. The system comprises: a coupling member, the coupling member being used to couple the curved object to the central axis; at least one recess, the at least one recess being integrally formed on the curved surface of the curved object and being defined as a recess relative to at least one of the inner surface and the outer surface. The recess comprises: a flat portion, the flat portion having a hole for accommodating the coupling member; and a flange portion, the flange portion continuously transitioning from the flat portion to the curved object and being shaped so that the flat portion is disposed perpendicular to the coupling member; and a fastening member, the fastening member being used to fasten the coupling member to the flat portion. The thickness of the flat portion and the flange portion is the thickness of the curved object.

Description

[0001] Statement regarding prior disclosures by the inventor or co-inventor

[0002] This patent application claims the benefit of U.S. Provisional Patent Application No. 63023969, filed on May 13, 2020, entitled “Provisional 5-20 Vertical Axis Wind Turbine Blade Connections.” Technical Field

[0003] The invention is concerned with solving the problem of attaching a curved structure (typically but not necessarily made of plastic or composite material) to another curved structure (in a typical embodiment a shaft). The main application envisaged here is small wind turbines, but is also applicable to other combinations of curved structures.

[0004] Related Technology: Not applicable. Summary of the invention

[0005] The present invention successfully addresses the disadvantages of currently known configurations by providing a better connection between the shaft and the curved structure.

[0006] Now firstly discloses a connection system for connecting a curved object to a central axis, wherein the curved object comprises an inner surface and an outer surface, wherein the inner surface faces the central axis, and the system comprises:

[0007] A coupling member, the coupling member being used to couple the curved object to the central axis;

[0008] At least one recess, the at least one recess being integrally formed on a curved surface of the curved object and being defined as a recess relative to at least one of the inner surface and the outer surface, the recess comprising:

[0009] a flat portion having a hole for receiving a coupling member; and

[0010] a flange portion, the flange portion continuously transitioning from the flat portion to the curved body and being formed so that the flat portion is disposed perpendicularly to the coupling member;

[0011] a fastening member for fastening the coupling member to the flat portion;

[0012] Among them, the thickness of the flat portion and the flange portion is the thickness of the curved object.

[0013] According to another embodiment, the coupling member is a rod, a first end of the coupling member is coupled to the central shaft, and a second end of the coupling member is coupled to the curved object.

[0014] In the system, the coupling member includes a bolt member and a rod, the bolt member is disposed in the hole, a first end of the rod is coupled to the central shaft and a second end of the rod is coupled to the bolt member.

[0015] According to another embodiment, the fastening member comprises at least one washer and one nut, and wherein the flat portion is configured to allow the washer and the nut to be placed on the flat portion.

[0016] According to another embodiment, a first piece of the flange portion protrudes from an outer surface of the curved object, a second piece of the flange portion protrudes from an inner surface of the curved object, and wherein the flat portion extends between the outer surface and the inner surface.

[0017] According to another embodiment, the flange portion protrudes from an inner surface of the curved object, and wherein the flat portion extends beyond the inner surface.

[0018] According to another embodiment, the first section of the flange portion includes a curve, the curve including aerodynamic properties configured to conform to aerodynamic properties of the curved surface.

[0019] According to another embodiment, the first section of the flange portion comprises a bend configured to have a smooth transition with respect to the bend of the curved surface.

[0020] According to another embodiment, the curved object is a wind turbine blade, and wherein the central shaft is configured to rotate through the wind turbine blade.

[0021] Now firstly a wind turbine blade for being coupled to a central shaft via a plurality of coupling members is disclosed, the wind turbine blade comprising:

[0022] The inner and outer surfaces facing the central axis;

[0023] A plurality of pockets integrally formed on the curved surface of the blade and defined as recesses relative to at least one of the inner surface and the outer surface and configured to receive one of the coupling members, the pockets comprising:

[0024] a flat portion having a hole for receiving one of the coupling members; and

[0025] a flange portion coupling the flat portion to the curved surface and shaped so that the flat portion is disposed perpendicular to the coupling member;

[0026] a fastening member for fastening the coupling member to the flat portion;

[0027] The thickness of the flat portion and the flange portion is at least the thickness of the curved object. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention is herein described, by way of example only, with reference to the accompanying drawings.

[0029] Figure 1 is a schematic diagram of a prior art blade and connection.

[0030] Figure 2 is a schematic diagram of a prior art blade and connection.

[0031] Figure 3 is a schematic diagram of a prior art thumb screw laminated to a blade.

[0032] Figure 4 is a schematic diagram of the recess and the rod.

[0033] Figure 5 yes Figure 4 Different perspective views of the recess and rod shown.

[0034] Figure 6 is a schematic diagram of a wind turbine.

[0035] Figure 7 is a schematic diagram of a separate rod and pocket system.

[0036] Figure 8 is a diagram of a wind turbine seen from one angle.

[0037] Fig. 9 Schematic diagram of a wind turbine from different angles.

[0038] Fig.10 is a diagram of a blade with a thumb screw in a recess.

[0039] Fig.11 is a schematic diagram of a turbine with one blade attached.

[0040] Fig.12 This is a diagram of the thumb screw recess as seen from the outside.

[0041] Fig.13 It is a schematic diagram of the thumb screw recess inside the blade.

[0042] Fig.14 is a cross-section through the cavity.

[0043] Fig.15 It is a diagram of a thumb screw.

[0044] Fig.16 is a schematic diagram of a thumb screw inserted according to the present invention. DETAILED DESCRIPTION

[0045] The present invention provides a better method of attaching a curved object to a central shaft.

[0046] Identification of terms in the accompanying drawings:

[0047] Bending objects or blades: 21

[0048] Center axis: 51

[0049] Pockets: 60

[0050] Openings in the pocket: 44, 54

[0051] Coupling member passing through opening in pocket: 24 or 70

[0052] Thumb screw: A coupling member that passes through an opening and has a stop on one side, which means that the coupling member and the fastening member will be part of one structure inside the curved object: 70

[0053] Flange: 22 or 23, 56

[0054] Fastening members, which in some cases may be trusses, which secure the connecting members to the structure of the shaft and the curved object: 25, 26, 27 or 53

[0055] The principles and operation of a curved object attached to a shaft according to the present invention may be better understood with reference to the drawings and description.

[0056] Now referring to the accompanying drawings, Figures 1 to 3 A problematic product based on prior art is shown.

[0057] Technical issues

[0058] In small vertical axis turbines, there are several ways to connect the blades to the rotating shaft. One is internal attachment inside the blade, where the blade various types of struts are attached only to the inside. Figure 3 is an example of this approach in the prior art, where bolts are placed from the inside from a post (also called an arm or flange) into the unequal thickness area of ​​the blade. This makes sense for some small turbines, but tends to be large and take up more space. These small turbines may also involve more work, for example, attaching fiberglass to the inside of the blade.

[0059] A low-cost alternative is to attach bars or rods to the blades, either attached to the side of the central shaft or through an opening in the central shaft. The problem is that these blades are round, making it difficult to attach them perpendicularly to the shaft.

[0060] Figure 1The solution is shown, which is to simply attach a rod, washer and nut (2) to the curved blade (1) at right angles. The result of this mismatch between the vertical force of the rod and its attachments and the curved blade, usually within a few years, will cause wrinkles (3) and thus breakage of the blade. We bought one of these to verify this poor design.

[0061] Figure 2 Another prior art solution is shown. A straight interface (12) is recessed from the blade surface, possibly made in a mould, which enables the rod and nut (11) to be connected in a wrinkle-free manner. (Note that the shape of the rod is not necessarily cylindrical.) The disadvantage here is that it creates a weak point in the blade because the area of ​​reduced thickness is adjacent to a thicker area. It is well known that a consistent and sufficient thickness helps to resist the strong forces generated by high winds, so the blade will not break due to stress in the area of ​​less thickness, and the connection is always the location of strong stress. However, this general principle is often ignored in order to facilitate attachment.

[0062] Figure 3 Another prior art commonly seen in composite blades is shown. Here, the thumb screw (15) is usually a metal part that looks like a thumbtack but is wider and thicker ( Fig.15 , 70), is attached to the interior of the blade only on one side, i.e. to the inner surface, and is laminated (16) on top of the inner surface of the blade at an interface (17) where there is a significant weak area that is susceptible to breaking at high rotational speeds. On the other side, the thumbscrew is attached to a connecting member that attaches the thumbscrew to the shaft. The thumbscrews therefore only change the thickness of the existing interior of the blade and present a surface, which leads to concerns that they will break in strong winds. The thumbscrews are also based on the curve of the inside of the blade, so that additional material that is easily stripped off fills the gap that does not match the shape of the thumbscrew and the curve of the blade. Another disadvantage is that the thumbscrews prevent close stacking of the blades during transportation. Another disadvantage is that the thumbscrews are difficult to assemble on site.

[0063] These prior art solutions using rods and blades of unequal size thickness render the blades much less durable than they should be.

[0064] Solution

[0065] Applicants have proposed a novel approach that maintains the thickness of the blade at the connection interface and addresses the deficiencies of current approaches using rods that provide a vertical surface for rod or other connector attachments that also exist on the outside and inside of the blade.

[0066] This solution is applicable in many situations, but the most common are wind turbine blades and shafts, so sometimes reference is made to wind turbine blades and shafts, without excluding other applications.

[0067] In summary, the present invention includes a combination of features that the prior art may not have utilized as a complete solution:

[0068] 1. A rod or connecting member extending from the outside to the inside. Also called a "connecting member". In some cases, people may also call it a "truss".

[0069] 2. The rod or flange is located in the recess of the blade and connected through the opening or hole.

[0070] 3. The pocket has a base that is perpendicular to the component connected to the shaft.

[0071] 4. The thickness of the material, typically a plastic, composite material, or a combination of metal and plastic, remains substantially continuous and smooth in the area of ​​the recess.

[0072] 5. Minimum impact on the outer or inner curvature of the blade.

[0073] Figure 4 A cross section of a blade (21) is shown. The blade has an inner surface (28) and an outer surface (29). When the rod approaches the interface for insertion of the rod, it changes its path to form a curved and protruding outer nub on the front surface of the blade (22) at the edge of the interface ("flange portion") with the flat portion (20), while maintaining the same thickness. Then, the rod (24) (which is a connecting member) advances straight in a plane perpendicular to the rod (24), and the connecting member is attached to a structural assembly collectively referred to as a "fastening member", in this case, washers (25, 26) and nuts (27) connecting the blade to the shaft via the connecting member. In this embodiment, (26) is a washer that fills a recess, which is considered a recess in the outer surface of the blade and extends from the flange portion of 22 to 23. The blade then forms an inner nub or protrusion (where 20 and 23 intersect), which protrudes slightly toward the inside of the blade so that the rest of the blade recovers the curvature of the surrounding blade without reducing the thickness and strength of the blade. The thickness of (22) is approximately the same as (23), and at (23) the blade returns to a similar bend as at (21). (22) and (23) together form a base for attaching the washer and rod within the recess. It should be noted that in an embodiment, the outer nub and the inner nub are approximately balanced.

[0074] The use of moulds of plastic and composite materials is an ideal way to manufacture such blades and interfaces. Moulds having the described characteristics are also included in the present invention.

[0075] Figure 5 is with Figure 4 The interface changes are shown in different cross-sectional views of the blade in close proximity. The blade (31) adjacent to the stem (35) and the outer protrusion (32) and inner protrusion (33) is completely smooth and continuous without any wrinkles or thickness variations. One can easily see that the outer protrusion 32 deflects the oncoming air, which provides resistance to the rotation of the blade leading edge on the nut (34), with minimal aerodynamic disturbance caused by the nut extension.

[0076] Figure 6 It is shown how this is achieved on a blade produced by the applicant's team.The blade (41) has a rod and a nub (42) attached to and passing through a central shaft (43). Fig.10 is a view of the alcove from the inside. Fig.11 Here is a view of the cavity from the outside. The part that one should notice is the base of the rod which is perpendicular to the axis.

[0077] Novel shapes of blades with nubs can be produced by making a mold with these features.

[0078] The result is a set of turbine blades that are more durable, less expensive and easier to assemble.

[0079] The present invention can be used on an asymmetric number of blades, where the rod is connected to one side of the shaft at one end and to the blade at the other end. The ideal embodiment is for a symmetrical even number of blades, where the rod (which may include several parts) extends through an opening on each side of the shaft, and the rod is fixedly attached to the interface of each blade on both distal sides of the rod.

[0080] The rod (or connecting member) does not have to be a single part. Figure 7 For a turbine having two blades and the rod (45) passing through the opening (44) in the shaft, as shown in the exploded view of FIG. 4 , the rod may comprise a set of parts that make up the rod. Figure 8 yes Figure 6 and Figure 7 A three-dimensional view of the entire turbine. The turbine comprises a shaft (47) and blades (41), the blades (41) being coupled to the shaft via coupling members (45) and fastening members (46). Fig. 9 Another view of the shaft (47), coupling member (45) and fastening member (46) is given.

[0081] Now we will consider Figure 3 Related solutions to the related problems shown.

[0082] Fig.10 First, an enlarged view is given. This view shows a blade with a thumb screw (49) on the blade, a part of which is used to connect to the connecting member pointing inwards. Fig.15 It is a figure of a thumb screw (70).

[0083] Fig.11 Also shown is an enlarged view of a cross section of the turbine and its blades. (50) is a blade, (51) is a shaft, (52) is a fastening member, the head of a thumb screw is inserted into a recess in the blade, and (53) is a coupling member or truss. Additional fastening members are not shown, and may be any additional screws or washers required to attach the coupling member to the fastening member.

[0084] Fig.12 The thumb screw pocket (54) is shown as a recess on the blade exterior (55). Fig.13 shows a thumb screw recess, connected to the Fig.12 The flange portion of the protrusion (56) on the inner part of the blade.

[0085] Fig.14 is a cross-section of blade (63). (60) is a recess. Recess (60) is a recess in the outer curved portion of the blade. (61) is the base of the recess. (62) is a hole or opening for allowing a thumb screw (in this case a "connecting member") to extend inwardly toward the shaft during attachment to the fastening member. It should be noted that the area around the thumb screw opening is equal to the thickness of the blade and is smoothly continuous with the rest of the blade. (64) is the flange portion between blade (63) and base (65). It should be noted that the angle of blade (63) resumes its curve after insertion into the recess.

[0086] Fig.16 The fiberglass blade of the present invention is shown, wherein the flange portion protrudes from the inner surface of the curved object, and wherein the flat portion extends outside the inner surface. (81) is the shaft of the thumb screw. (80) is the protrusion of the flange portion. Fig.16 In the example, the base of the thumb screw is not visible because it is buried in the recess and partially covered by the flange. (80) Fig.13 The same as (56). Figure 3 There are important comparable aspects to the prior art. Fig.16 The new technology in the car is less aerodynamically stiff, stronger and smoother.

[0087] While the invention has been described with respect to a limited number of embodiments, it will be appreciated that the invention is susceptible to numerous variations, modifications, and other applications.

Claims

1. A coupling system for coupling a curved object to a central axis, the curved object comprising an inner surface and an outer surface, the inner surface facing the central axis and the outer surface facing an opposite direction, the system comprising: a coupling member for coupling the curved object to the central axis; At least one recess, the at least one recess being integrally formed on the curved surface of the curved object and being defined as a recess relative to at least one of the inner surface and the outer surface, the recess comprising: a flat portion having a hole for receiving the coupling member; and a flange portion which continuously transitions from the flat portion to the curved object and is shaped so that the flat portion is disposed perpendicularly to the coupling member; a fastening member for fastening the coupling member to the flat portion; wherein the thickness of the flat portion and the flange portion is the thickness of the curved object, and, The flat portion extends between a first end protruding from the outer surface away from the central axis and a second end protruding from the inner surface facing the central axis.

2. The system according to claim 1, wherein: The coupling member is a rod, a first end of the coupling member is coupled to the central shaft, and a second end of the coupling member is coupled to the bending object.

3. The system according to claim 1, wherein: The coupling member includes a bolt member and a rod, the bolt member is disposed in the hole, a first end of the rod is coupled to the central shaft and a second end of the rod is coupled to the bolt member.

4. The system according to claim 1, wherein: The fastening member comprises at least one washer and a nut, and wherein the flat portion is configured to allow the washer and the nut to be placed on the flat portion.

5. The system according to claim 1, wherein: A first small piece of the flange portion protrudes from the outer surface of the curved object, and a second small piece of the flange portion protrudes from the inner surface of the curved object.

6. The system according to claim 1, wherein: The flange portion protrudes from the inner surface of the curved object, and wherein the flat portion extends beyond the inner surface.

7. The system according to claim 5, wherein: The first section of the flange portion includes a curve including aerodynamic properties configured to conform to aerodynamic properties of the curved surface.

8. The system according to claim 7, wherein: The first section of the flange portion includes a curve configured to have a smooth transition relative to a curve of the curved surface.

9. The system according to claim 1, wherein: The curved object is a wind turbine blade, and wherein the central shaft is configured to rotate through the wind turbine blade.

10. A wind turbine blade for coupling to a central shaft via a plurality of coupling members, the wind turbine blade comprising: an inner surface and an outer surface, the inner surface facing the central axis and the outer surface facing an opposite direction; a plurality of recesses integrally formed on the curved surface of the blade and defined as recesses relative to at least one of the inner surface and the outer surface and configured to receive one of the coupling members, the recesses comprising: a flat portion having a hole for receiving one of the coupling members; and a flange portion coupling the flat portion to the curved surface and shaped so that the flat portion is disposed perpendicular to the coupling member; a fastening member for fastening the coupling member to the flat portion; wherein the thickness of the flat portion and the flange portion is at least the thickness of the curved object, and The flat portion extends between a first end protruding from the outer surface away from the central axis and a second end protruding from the inner surface facing the central axis.

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