Patent Publication Number: US-2019170195-A1

Title: Compression mode flexible couplings

Description:
BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     This disclosure relates to new and improved flexible couplings and, more particularly, to an improved flexible coupling which operates in compression mode and features a wrap-around flexible insert which can be removed and replaced without moving hub components with which the flexible insert interacts. 
     Description of Related Art 
     Flexible couplings have long been used for the purpose of transmitting rotation from one shaft to another. Such couplings are normally used in order to accommodate comparatively minor shaft alignment problems such as are occasionally encountered because of manufacturing or assembly errors or equipment tolerances. 
     SUMMARY 
     The following is a summary of various aspects and advantages realizable according to various aspects of the disclosure. It is provided as an introduction to assist those skilled in the art to more rapidly assimilate the detailed design discussion which ensues and does not and is not intended in any way to limit the scope of the claims which are appended hereto in order to particularly point out the invention. 
     Accordingly, described hereafter is coupling apparatus comprising first and second hubs, each having a cylindrical segment and a plurality of projecting teeth and a flexible insert wrappable around the first and second hubs and having a plurality of interior projections defining a plurality of receptacles for receiving the hub teeth. A retainer ring is removably attachable about the flexible insert to hold it in an installed position about the first and second hubs. 
     According to an illustrative embodiment, the number of teeth projecting from the first hub is the same as the number of teeth projecting from the second hub, and the flexible insert has a number of receptacles equal to the total number of hub teeth. According to this embodiment, the teeth of the first hub occupy every other receptacle of the insert, and the teeth of the second hub occupy the remaining receptacles of the insert, such that the teeth of the first hub alternate with those of the second hub around a circumference of the flexible insert, yielding a coupling which operates in compression mode. 
     According to one embodiment, the insert is split so as to facilitate a wrap-around installation and removal procedure with respect to the cooperating first and second hub components. According to this procedure, the first and second hubs are installed in place on respective opposing shafts and properly aligned prior to installation of the insert. The flexible insert is then wrapped around the teeth of the installed first and second hubs. The retaining ring is then slid over the insert, encapsulating the insert so as to hold it in engagement with the hub teeth. The flexible insert can then be easily replaced by simply sliding back the retaining ring, unwrapping the installed insert, replacing it with a new insert, and re-installing the retaining ring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective of a flexible coupling according to a preferred embodiment; 
         FIG. 2  is a perspective view of the coupling in the assembled state; 
         FIG. 3  is a perspective view of a hub component of the illustrative embodiment; 
         FIG. 4  is a side sectional view of the hub component taken at IV-IV of  FIG. 3 ; 
         FIG. 5  is an end view of the hub component of  FIG. 3 ; 
         FIG. 6  is an end view of a flexible insert component of the illustrative embodiment; 
         FIG. 7  is an end view of a retainer ring component of the illustrative embodiment; and 
         FIG. 8  is a side cross-sectional view of the illustrative embodiment taken at VIII-VIII of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED OF PREFERRED EMBODIMENTS 
     The coupling  11  of the illustrative embodiment includes a first hub  13 , a flexible insert  15 , a second hub  17  and a retainer ring  19 . In the illustrative embodiment, the first and second hubs  13 ,  17  are identically shaped and have a plurality of teeth  21  projecting horizontally therefrom. The flexible insert  15  has a circular outer perimeter and a plurality of vertically depending interior projections  23 , which define a plurality of receptacles  25  for receiving respective teeth  21 . 
     In the illustrative embodiment of  FIG. 1 , the number of receptacles formed in the flexible insert  15  is twice the number of teeth  21  formed on one of the hubs  13 ,  17 . For example, in the embodiment of  FIG. 1 , each hub has six teeth  21 , and the flexible insert  15  has twelve receptacles  25 . When assembled, the teeth  21  of the first hub  13  occupy every other receptacle  25 , and the teeth  21  of the second hub  17  occupy the remaining receptacles  25 , such that the teeth  21  of the first hub  13  alternate with those of the second hub  17  as one proceeds around the circumference of the flexible insert  15 . The number of teeth  21  and receptacles  25  may vary in various other embodiments. 
     As shown in  FIGS. 3-5 , in the illustrative embodiment, each hub  13 ,  17  includes an interior bore  27 , a first cylindrical segment  29  of a first diameter d 1 , and a second cylindrical segment  30  of a larger second diameter and having a width d 8 . A number of teeth  21  are unitarily formed with the cylindrical segment  30 , each projecting a selected distance d 2  from its outer perimeter. Each tooth  21  has parallel rectangular side surfaces  31  and a rectangular end  33 . 
     Conventional fastening devices such as set screws  28  may be used to secure the hubs  13 ,  17  to respective shafts of cooperating apparatus. In the illustrative embodiment, the hubs  13 ,  17  may have dimensions d 1 , d 2 , d 3 , d 4  and d 8  in inches of respectively 2.3700, 0.6000, 0.2646, 0.4300, and 0.2650. Such dimensions will of course vary in other embodiments. In the illustrative embodiment, the teeth  21  are equally spaced around the circumference of each hub  13 ,  17 , separated by an angle of 60 degrees from one another. Each hub  13 ,  17  is preferably machined as a unitary part from a single piece of metal stock, but of course could be constructed in various other fashions. 
     The flexible insert  15  is further illustrated in  FIG. 6  and is preferably fabricated from a flexible material such as, for example, a suitable urethane, such as polyurethane. The insert  15  preferably includes a split  40  so as to facilitate “wraparound” installation as further described below. 
     In one embodiment, the projections  25  depending from the interior surface of the insert  15  are identically shaped and are formed about equally spaced radii extending from the center of the insert  15 . In one embodiment, the inner diameter d 7  may be 1.6500 inches. The angle B formed by the respective sides, e.g.  35 ,  37 , of each projection  25  is thirty degrees in the illustrative embodiment, but may differ in other embodiments. The receptacles  25  defined by the projections  23  may be rectangular in cross-section d 6 , which may be 0.2850 inches in the illustrative embodiment, but may differ in other embodiments. In such an embodiment, the overall diameter d 5  of the insert  15  is 2.850 inches, but may also differ in other embodiments. Oppositely disposed grooves  39  are formed on the outer surface of the insert  15  to accommodate retainer pins  41  formed on the interior of the retainer ring  19 , whose inside diameter d 8  ( FIG. 7 ) may be 2.880 inches in the illustrative embodiment. 
     In operation in the assembled state ( FIGS. 2, 8 ), the flexible insert  15  is snugly encased and transmits torque and absorbs minor misalignments. Each projection  25  of the flexible insert  15  is entirely encased between a face of a tooth  21  of the first hub  13  and a face of a tooth  21  of the second hub  17 , as illustrated, for example, in  FIG. 8 . In the illustrative embodiment, the width W 1  of the insert  15  is the same as the width of each receptacle  25  and each projection  23 . The width W 1  is selected in one embodiment such that the teeth  21  of a respective hub  13 ,  17  completely fill each respective receptacle  25 , but are spaced apart so as not to contact the oppositely disposed hub  17 ,  13 , as illustrated in  FIG. 8 . The coupling  11  operates in compression mode, while enabling the flexible insert  15  to be removed for replacement without disturbing the position of the hubs  13 ,  17  and without requiring the detachment of the hubs  13 ,  17  from their cooperating shafts. 
     To install the coupling  11 , the hubs  13 ,  17  are fastened to respective shafts on the driving and driven sides employing, for example, the respective set screws  28 . Each of the shaft hubs  13 ,  17  can be installed respectively on the driving and driven sides and then moved into place and aligned. The insert  15  and ring  16  are then installed. The urethane insert  15  is cut in one place, so that it can be wrapped around the installed shaft hubs  13 ,  17 , and the retaining ring  16  can then be slid over the outside diameter of the insert  15 . If the insert  15  needs replacement, the ring  16  can be slid off the insert  15 , and the insert  15  can thereafter be unwrapped and replaced. 
     While the present invention has been described above in terms of specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. Thus, the present invention is intended to cover various modifications and equivalent methods and structures included within the spirit and scope of the appended claims.