Abstract:
A coupling assembly is provided at each end of a shaft. The coupling assemblies include flange member having a radially extending flange having a first outer pattern of fastener attachment points, a first flex element having a second outer pattern of fastener attachment points, and also having a first inner pattern of fastener attachment points, a second flex element having a third outer pattern of fastener attachment points, and also having a second inner pattern of fastener attachment points, a first set of spacers disposed in between the first flex element and the flange and located between the first outer pattern and the second outer pattern of fastener attachment points, a second set of spacers disposed between the first flex element and the second flex element and located between the second outer pattern and the third outer pattern of fastener attachment points, a collar having a third inner pattern of fastener attachment points, and a third set of spacers disposed between the first flex element and the second flex element between the first inner pattern and second inner pattern of fastener attachment points. A variation is disclosed which uses a single flex element.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention pertains generally to the field of rotational shaft couplings or connections. Further, the invention pertains to such connections or couplings which can transmit rotational torque between two shafts and/or hubs, while accommodating center-line misalignment between the shafts on both sides of the coupling. 
       BACKGROUND OF THE INVENTION 
       [0002]    Various ways of coupling two rotational shafts and/or hubs together are known in the art. Often times, the couplings are used to transmit torque or rotational power from a drive shaft or hub to a driven drive shaft or hub. Thus, typically on one side of the coupling there is a power inducing device such as a motor, and on the other side of the coupling there is a shaft input to a power receiving device. 
         [0003]    One example of such an arrangement is in a drive system for a fan used in an atmospheric cooling tower. In such a situation, it is common for the fan to be a relatively large horizontal or vertical axial fan. Often times, the blades are mounted to a hub and gear box in the center of the fan assembly, which is the axis about which the fan rotates. The gear box is often a 90 degree gear box, such that the axis of the input shaft to the gear box is at a right angle compared to the center line axis of the fan. Typically, a power transmission shaft extends from the center gear box along and past the radial swept area length of the fan, to a motor which is radially disposed outside the periphery of the fan. In this way, the motor is outside the swept area of the fan and does not block the air flow through the fan. Further, the gear box can be made relatively compact and rests in the center of the fan underneath the fan center hub. 
         [0004]    The systems described above have proven highly satisfactory in use. However, particularly due to the length of the power transmission drive shaft, and to the construction of cooling towers in general, it has often been difficult to maintain a precise alignment between (1) the output shaft center axis of the motor, (2) the shaft center axis, and (3) the input shaft center axis of the gear box. Any misalignment is exacerbated by the relatively long length of the transmission shaft. 
         [0005]    One solution to this issue has been to provide some form of torque tube or other rigid device spanning between the motor and the gear box. However, torque tubes do not always provide or maintain satisfactory alignment by themselves. 
         [0006]    Accordingly, there is a need in the art for an improved connection or coupling which can be interposed at one or both ends of a shaft or hub, such as a driven shaft between a motor and a gear box, in order to accommodate misalignment that may occur. 
       SUMMARY OF THE INVENTION 
       [0007]    Some embodiments of the invention provide an improved connection or coupling which can be interposed at one or both ends of a shaft or hub, such as a driven shaft between a motor and a gear box, in order to accommodate misalignment that may occur. 
         [0008]    In one embodiment of the present invention, a coupling assembly for a fan drive in an atmospheric cooling tower has a flange member with a radially extending flange on a first outer pattern of attachment points and a flex element with a second outer pattern of fastener attachment points. The assembly also has a first inner pattern of fastener attachment points, a set of spacers disposed in between the first flex element and the flange and located between the first outer pattern and the second outer pattern of fastener attachment points, a collar having a third inner pattern of fastener attachment points, and a set of first fasteners that pass through all of the outer attachment points to fasten the flex element and the flange to each other maintaining spacing between the flange and the flex element due to the spacers being trapped therebetween. A second set of fasteners passes through all the inner attachment points to fasten the flex element and the collar together in an abutting relationship. 
         [0009]    Another embodiment of the present invention details a coupling assembly comprising a flange member having a radially extending flange having a first outer pattern of fastener attachment points, a first flex element having a second outer pattern of fastener attachment points, and also having a first inner pattern of fastener attachment points, a second flex element having a third outer pattern of fastener attachment points, and also having a second inner pattern of fastener attachment points, a first set of spacers disposed in between the first flex element and the flange and located between the first outer pattern and the second outer pattern of fastener attachment points, a second set of spacers disposed between the first flex element and the second flex element and located between the second outer pattern and the third outer pattern of fastener attachment points, a collar having a third inner pattern of fastener attachment points, and a third set of spacers disposed between the first flex element and the second flex element between the first inner pattern and second inner pattern of fastener attachment points. 
         [0010]    A further embodiment of the coupling assembly comprises a shaft, a first mounting means having a radially extending flange having a first outer pattern of fastener attachment points, a first flowing means having a second outer pattern of fastener attachment points, and also having a first inner pattern of fastener attachment points, a second flowing means having a third outer pattern of fastener attachment points, and also having a second inner pattern of fastener attachment points, a first set of spacing means disposed in between the first flexing means and the flange and located between the first outer pattern and the second outer pattern of fastener attachment points, a second set of spacing means disposed between the first flexing means and the second flexing means and located between the second outer pattern and the third outer pattern of fastener attachment points, a second mounting means having a third inner pattern of fastener attachment points, and a third set of spacing means disposed between the first flexing means and the second flexing means between the first inner pattern and second inner pattern of fastener attachment points. 
         [0011]    Yet another embodiment relates to a fan drive assembly, which has a motor, a shaft, a gear box, a pair of couplings, one at each end of the shaft, one coupling joining the shaft to the motor, and one coupling joining the shaft to the gear box. Each coupling comprises a flange member having a radially extending flange having a first outer pattern of fastener attachment points, a first flex element having a second outer pattern of fastener attachment points, and also having a first inner pattern of fastener attachment points, a second flex element having a third outer pattern of fastener attachment points, and also having a second inner pattern of fastener attachment points, a first set of spacers disposed in between the first flex element and the flange and located between the first outer pattern and the second outer pattern of fastener attachment points, a second set of spacers disposed between the first flex element and the second flex element and located between the second outer pattern and the third outer pattern of fastener attachment points, a collar having a third inner pattern of fastener attachment points, a third set of spacers disposed between the first flex element and the second flex element between the first inner pattern and second inner pattern of fastener attachment points, and a hub. 
         [0012]    In yet another embodiment, a coupling method provides a shaft wherein the coupling devices each comprise a flange member having a radially extending flange having a first outer pattern of fastener attachment points, a first flex element having a second outer pattern of fastener attachment points, and also having a first inner pattern of fastener attachment points, a second flex element having a third outer pattern of fastener attachment points, and also having a second inner pattern of fastener attachment points, a first set of spacers disposed in between the first flex element and the flange and located between the first outer pattern and the second outer pattern of fastener attachment points, a second set of spacers disposed between the first flex element and the second flex element and located between the second outer pattern and the third outer pattern of fastener attachment points, a collar having a third inner pattern of fastener attachment points, and a third set of spacers disposed between the first flex element and the second flex element between the first inner pattern and second inner pattern of fastener attachment points. 
         [0013]    There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
         [0014]    In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
         [0015]    As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view showing a motor, a drive shaft, a gear box, and two flexible couplings according to a preferred embodiment of the present invention. 
           [0017]      FIG. 2  is side view of the arrangement of  FIG. 1 . 
           [0018]      FIG. 3  is a partially exploded perspective view of the arrangement of  FIG. 1 . 
           [0019]      FIG. 4  is a further exploded perspective view of the arrangement of  FIG. 1 , taken from an angle different from that of  FIG. 3 . 
           [0020]      FIG. 5  is a view showing a drive shaft and two flexible couplings. 
           [0021]      FIG. 6  is a side view of the arrangement of  FIG. 5 , further showing an embodiment wherein one of the flexible couplings features a coating on some parts thereof. 
           [0022]      FIG. 7  is a perspective end view of the arrangement of  FIG. 5 , showing further details thereof. 
           [0023]      FIG. 8  is a partially exploded view of the arrangement of  FIG. 5 , showing further details thereof. 
           [0024]      FIG. 9  is a close up exploded view showing details according to  FIG. 8 . 
           [0025]      FIG. 10  is a perspective view of an individual flex element according to the embodiment illustrated in  FIGS. 1-9 . 
           [0026]      FIG. 11  is a perspective view of an alternative flex element providing an alternative flex element embodiment that can be used in the arrangements of  FIGS. 1-9 . 
           [0027]      FIG. 12  is a perspective view of an alternative flex element providing an alternative flex element embodiment that can be used in the arrangements of  FIGS. 1-9 . 
           [0028]      FIG. 13  is an exploded view of an alternative embodiment of a coupling using a single flex element. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    Some embodiments according to the present invention provide an improved connection or coupling which can be interposed at one or both ends of a shaft or hub, such as a driven shaft between a motor and a gear box, in order to accommodate misalignment that may occur. 
         [0030]    The embodiments described herein in general relate to a coupling arrangement that can couple between two rotating shafts or hubs. The shafts may be, for example, longitudinal transmission shafts, or may be the input or output shafts of a motor or driven assembly such as a gear box. The word shaft here, then, refers to any rotational item such as a shaft, hub, flange, stub or other power transmitting member, whether solid or hollow, and whether having a cylindrical outer surface or whether having a round, hexagonal, square, octagonal, keyed, or any other shaped outer surface. Further, the description throughout herein will use the terms coupling and connector interchangeably, and no distinction between those terms is intended. 
         [0031]    Some preferred embodiments of the invention will now be described with reference to the drawing figures in which like parts refer to like elements throughout. Turning to  FIG. 1 , a system is illustrated including a motor  12 , which in this example is an electric motor, but could also be a hydraulic motor or any other type of rotational power source. A shaft  14  is illustrated which transmits rotational power and/or torque to a gear box  16 . In the present example, the gear box  16  is a gear box that drives a fan having blades (not shown) extending radially outward from a shaft  17 . A pair of couplings  20  are disposed at the opposed ends of the shaft  14 . These couplings  20  transmit rotational power and/or torque on one end from the motor  12 , and on the other end to the gear box  16 . 
         [0032]    The couplings  20  transmit such rotational power and/or torque, while accommodating some axial or angular misalignments between the center lines of the shaft  14  and the output shaft  12  and/or the input shaft of the gear box  16 , respectively. These alignments can include purely angular misalignments between the center lines of the shafts, or also an offset type lateral alignment between the shafts, and/or combinations thereof.  FIG. 2  shows a side view of the arrangement of  FIG. 1 . 
         [0033]    Turning to  FIGS. 3 and 4 , further details of the couplings  20  are shown. In particular, each coupling  20  includes four major components. Each coupling  20  has a flange member  22 , which is attached to the shaft  14 , typically by bonding or other rigid attachment method. The coupling  20  further includes two flex elements  30 , which are relatively thin plates or discs and are described further below. Each coupling  20  also includes a collar  36 , which is a stub shaft that has inner or outer features in order to be mated to the output shaft of the motor  12 , or the input shaft of the driven device such as the gear box  16 . In the examples shown, the shaft  14  is a hollow shaft, which may be made of any suitable material such as, for example, carbon fiber tubing, or metal. Turning to  FIGS. 5 and 6 , it will be appreciated that when assembled, the flange member  22  includes a cylindrical portion  23  having an outer diameter to fit in the inner diameter of the shaft  14  and be bonded thereto. With further reference to  FIG. 8 , the flange  22  also has a radially extending flat flange portion  24 , in addition to a cylindrical insert portion  23 . 
         [0034]    Continuing with reference to  FIGS. 5-9 , it will be appreciated that the flange portion  24  has a set of (in this case four) fastener holes  40  therethrough. Aligned with these fastener holes are a series of (in this case four) spacer/washers  28 . The couplings  20  each include a pair of flex elements  30 , which each also have a set of matching (in this case four) fastener holes  40 , with spacer/washers  32  between the pair of flex hubs at the locations of the holes  40 . In this way, it will be appreciated a fastener  39  can be inserted through a first hole  40 , a washer  32 , a second hole  40 , a washer  28 , and into or through a hole  25 , and tightened either by being tightened into threaded hole  25 , or by a nut (not shown) on the opposite side of the flange  24 . Therefore, an assembly is created as shown in side views in  FIG. 6 , wherein two flex elements  30  are mounted essentially parallel to, but spaced apart from, the flange  24 . Further, the flex elements  30  are spaced apart from each other, in a preferred embodiment by a distance less than a spacing from the middle flex element to the flange  24 . 
         [0035]    Further, as best seen in  FIG. 10 , each of the flex elements  30  has near an inner circle  41  a circular ring of (in this case eight) fastener holes  42 . A matching ring of (in this case eight) spacer/washers  35  is provided between the two flex elements  30 , and though not visible due to the angle, the collar  36  has a matching ring of (in this case eight) threaded fastener bores. Thus, fasteners  29  can be inserted through first hole  42 , a washer  35 , a second hole  42 , and the respective receiving bore in the collar  36 . In this way, again, an arrangement is formed such as shown on the left side in  FIG. 6 , with the flex elements  30  spaced apart for each other, and one flex element abutting the collar  36 . Given the arrangement shown above, as far as practical assembly, it may be most practical to first assemble the collar to two of the flex elements  30 , and then to attach the collar and joint flex element assembly as one piece together onto the flange  24 . 
         [0036]      FIG. 6  on its right side shows an alternative embodiment wherein an elastomeric coating  21  has been applied around parts of the coupling  20  in order to seal parts of the coupling  20 . In one embodiment the collar  36  and flex elements  30  are coated, but the hub  22  is not coated; this facilitates replacement of the flex elements  30  without damaging the coating or need to re-apply any coatings. A unit of flex elements  30  and collar  36  can be pre-coated before installation. Thus, the coating feature is illustrated only schematically, and some or all components can be coated (alone or together). If the elastomeric coating  21  is suitably resilient, it can seep in between various parts of the coupling  20  without interfering with its function. Such coatings  21  on some form of pre-molded covers can be used on any couplings where suitable. 
         [0037]    The flange member  22  should be of a design that is easily bondable or attachable to the shaft  14 , for example by adhesive insertion of the cylindrical portion  23 , and further which is stiff and rigid enough to provide fastener mounting locations (holes  25 ) for attachment to the flex elements  30 . The flange element  22  may be made of some form of steel, or preferably a composite such as, e.g, fiberglass and epoxy. Also, although the flange member  22  is shown as a component that is originally separate from the shaft  14 , depending on the shaft manufacturing employed, the shaft  14  and the flange element  22  may be in some form unitary. 
         [0038]    The flex elements  30  are typically relatively thin plates, and can be made of steel, including for example carbon steel or stainless steel, or preferably be a composite. These materials provide a desirable resilient or spring-back flex property. If the embodiment utilizes the coating  21  shown in  FIG. 6 , then the corrosion performance of the material is less important, depending on the environment which the couplings  20  are used. However, if the coating  21  is omitted, a weather or corrosion resistant material such as stainless steel may be preferred. 
         [0039]    Turning to  FIG. 9 , it will be appreciated that the collar  36  shows a key-way  37 , shown by way of example only to illustrate that the collar  36  can be rotationally locked to some shaft, such as the output shaft of a motor  12 . 
         [0040]    Turning to  FIG. 10 , it will be appreciated that the example shown of a flex element  30  has a relatively square outer profile and cutouts  46  and  48 . These cutout regions  46  and  48  allow the flex element  30  to bend, and in particular allow the region of the flex element having the fastener holes  40  to tilt geometrically relatively to the region of the flex elements having the fastener holes  42 . Since the fasteners  29  are ultimately attached to the collar  36 , and the fasteners  39  are ultimately attached to the flange member  22  and thus indirectly to the shaft  14 , this flexing permits accommodation of misalignment between the collar  36  and the shaft  14  itself. 
         [0041]      FIG. 11  shows a different shape of a flex element  50 , in this case having center aperture  54 , a ring of fastener holes  51 , an outer ring of fastener holes  52 , and four cutouts  56 .  FIG. 12  shows another embodiment of a flex element  60 , in this case having an inner aperture  64 , an inner ring of inner bolts  61 , an outer ring of fastener holes  62 , and four cutouts  66 . The shape shown in  FIGS. 11 and 12  also serve the same general function as that of  FIG. 10 . 
         [0042]    Although the preferred embodiments have been described in the context of being on both ends of a shaft which is driving a fan in a cooling tower, the couplings can have wide range of applicability, and in some arrangements only one coupling may be employed rather than two. In further arrangements, more than two couplings may be employed. Further, such couplings can be used outside of the fan drive implementation and outside of the cooling tower industry. 
         [0043]      FIG. 13  is an exploded view of an alternative embodiment of a coupling with the single flex element. Some of the embodiments described above use two flex elements, with spacers in between the two flex elements. Of course, more than two flex elements can be used according to various alternative embodiments of the invention. Additionally, embodiments are possible using only a single flex element, as illustrated in  FIG. 13 .  FIG. 13  shows a coupling element  120  which can be used in some or all of the same applications as discussed above for the other embodiments. The coupling  120  has a flange member  122  which is attached to the shaft similar to the previously described embodiments. The coupling further includes a single flex element  130 . The flex element  130  may be substantially similar to any of the flex elements  30  described above, and includes passing therethrough an outer ring of fastener holes  140 , as well as an inner ring of fastener holes  142 . In the embodiment illustrated, the flex element  130  does not have a central aperture therethrough. It will be appreciated in all embodiments the flex elements  30  or  130  can feature central apertures or not, and can also feature additional supplemental cutout or relief regions or not. The single flex element  130  in this embodiment can be manufactured of steel or composite, similar to the previous embodiments, and is preferably a relatively thin flat disc, as in the previous embodiments. The coupling  120  as illustrated in  FIG. 13 , also includes a flange  124 , washers or spacers  128 , and bolts  139  that interact with nuts  138 , so that the bolts  139  can affix the flex element  130  against the washers  125  and thus spaced apart from the flange  124 . Bolt holes  125  are provided to receive the bolts  139 , and can either be threaded or the nuts  138  can be used. 
         [0044]    In addition in this embodiment, a set of inner fasteners  129  are provided, which pass through holes  142  in the flex element  130  and into receiving bores (not shown) in the face of the hub or collar  136 , such that tightening the fasteners  129  pulls the flex element  130  flush with the end face of the collar  136  and mounts it thereto. 
         [0045]    The various embodiments discussed above can be used to connect shafts or hubs anywhere along a drive system, but in some examples are used to connect a motor to a fan gear drive box. In the embodiments illustrated many of the Figures herein, the drive shaft is a relatively elongated shaft. However, it will be appreciated that couplings such as described herein, can also be used in close-coupled arrangements, wherein the shaft is very short, or even the coupling on one end is directly attached to the motor and on its other end is directly attached to the gear drive box. 
         [0046]    The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.