Abstract:
A coupler for connecting rotary members to facilitate transfer of torque between the members where the rotational axes of the members are not in axial alignment.

Description:
SUMMARY OF THE INVENTION  
         [0001]    This invention is directed to a coupler for interconnecting rotary members in order to facilitate relative motion between them as they transmit torque where the rotational axes of the members are out of axial alignment.  
           [0002]    More specifically, the coupler comprises a female portion that extends from one of the members, and a male portion that extends from the other of the members. The female portion has at least one axially extending interior wall defining a socket. The interior wall includes at least one head-engaging surface portion. The male portion has a neck and a head. The head includes at least one wall-engaging surface portion. The head is sized and adapted to be received in the socket. The female portion and the male portion are shaped and adapted such that with the male portion positioned in the female portion and the members rotated, the wall-engaging surface portion is in engagement with the head-engaging surface portion such that rotation of one member about its axis imparts rotation to the other member about its axis even with the axes out of axial alignment.  
           [0003]    Another aspect of the present invention is a method of rotating a first member to impart rotation to a second member. The, method includes providing a coupler as previously described, and further includes inserting the male portion in the female portion and rotating the first member about its axis while the wall engaging surface portion is in engagement with the head engaging surface portion to cause the second member to rotate about its axis even with the axes out of axial alignment.  
           [0004]    Other features and advantages will be apparent from the description and claims to follow. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is a perspective view of an embodiment of the coupler of the invention showing the male and female portions;  
         [0006]    [0006]FIG. 2 is a perspective view with a cutaway portion of the coupler of FIG. 1 in a connected configuration and with the axes of the male and female portions out of alignment;  
         [0007]    [0007]FIG. 3 is a front plan view of the coupler of FIG. 1 in a connected configuration;  
         [0008]    [0008]FIG. 4 a  is a cross-section view taken along line  4 - 4  of FIG. 3;  
         [0009]    [0009]FIG. 4 b  is a view like FIG. 4 a  but showing the head of the male portion in engagement with the wall of the female portion where rotation of one imparts rotation to the other;  
         [0010]    [0010]FIG. 5 is a front plan view of the male portion of FIG. 1;  
         [0011]    [0011]FIG. 6 is a front plan view of the female portion of FIG. 1;  
         [0012]    [0012]FIGS. 7 a  and  7   b  are schematics showing the relationships between the male and female portions at different positions of rotation; and  
         [0013]    [0013]FIG. 8 is a cross section view showing a retainer in accordance with the invention. 
     
    
       [0014]    Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    Referring to the drawings, FIG. 1 shows a coupler  20  of the present invention. The coupler includes a male portion  22  and a female portion  24  extending from first and second members  26 ,  28 , respectively. Although the male portion is shown associated with the member  26  and the female portion with the member  28 , it is to be understood that the male or female portion may be associated with either member. The male portion  22  has a neck  30  and an enlarged head  32 . As shown in the drawings, and particularly FIG. 5, the head of this described embodiment is of a generally triangular shape when viewed in a plane perpendicular to the rotational axis  33  of the male portion, forming three rounded lobes  34  joined by generally straight portions  36  between the lobes. The lobes  34  are symmetrical about the rotational axis of the male portion. The head has a smooth outer circumferential surface  38  that is rounded as shown, for example in FIG. 5. The junction between the neck and head is formed by a smooth radius  40 .  
         [0016]    The female portion  24  has an interior wall  44  that forms a socket  46  that receives the head of the male portion. In this described embodiment, the shape of the socket when viewed in a plane perpendicular to the rotational axis  48  of the female portion is generally triangular to correspond with the generally triangular shape of the head of the male portion, and the socket is symmetrical about the rotational axis of the female portion. The socket and head are sized such that with the head inserted in the socket there is clearance between the rounded circumferential surface of the head and the socket wall as shown in FIG. 4 a.  Also, the socket is of sufficient depth so as to provide a range of longitudinal (axial) positions of the head within the socket while still providing rotational engagement (see, for example, FIG. 3).  
         [0017]    In this described embodiment of the invention, the male and female portions each are of monolithic construction, although it is to be understood that other types of construction may also be used for either or both components. Also, it is to be understood that the male and female components may be formed from various materials, depending on the applications for which they are used, and it further is to be understood that the male and female components need not necessarily be formed of the same materials, it being preferred that the particular construction and materials be selected to provide minimum wear and maximum life taking into account cost considerations for a particular application. Also, while with this described embodiment the head and socket are of generally triangular configurations, it is to be understood that other suitable configurations could also be used depending on the particular application for the coupler.  
         [0018]    In operation, the coupler is assembled by inserting the head of the male portion into the socket of the female portion. As shown in FIGS. 2 and 7, the rotational axes of the male and female portions can be out of axial alignment as shown by the angle A (FIG. 7). As shown in FIG. 4 a,  there is sufficient clearance between the head and socket to allow for easy insertion of the head into the socket. After the coupler is assembled, initial rotation of one of the members  26 ,  28  will cause the male or female portion to rotate relative to the other until wall-engaging surface portions  50  of the male portion engage head-engaging surface portions  52  of the female portion as shown in FIG. 4 b.  Continued rotation of the one member (drive member) imparts rotation to the other member (driven member) even with the axes of the two members out of alignment as shown in FIGS. 2 and 7. As the members rotate, the outer rounded surfaces of the lobes slide in the axial direction along the socket wall as shown in FIGS. 7 a  and  7   b.  FIG. 7 a  shows the position of one of the lobes  34  at a first rotational position of the coupler with its rounded outer surface contacting the wall of the socket at a location  60 , while FIG. 7 b  shows the same lobe  34  with its outer surface contacting the wall of the socket at a different location  62  at a second rotational position of the coupler. It will be noted that during rotation from the position of FIG. 7 a  to the position of FIG. 7 b,  the lobe slides along the cavity wall in an axial direction to accommodate the axial misalignment of the rotating members. As the rotation continues through a complete revolution, the lobe shown in FIG. 7 will move axially in the other direction to return to the position shown in FIG. 7 a.  This back and forth axial sliding of each of the three lobes is continuous as the members rotate to accommodate for the misalignment of the rotating axes of the members. The engaging surface of the male and female portions should be smooth to minimize friction. Thus, it is important that the shape of the male and female portions must be such that rotation of one of the members  26 ,  28  imparts rotation to the other of the members even though their rotating axes are out of alignment.  
         [0019]    With reference to FIG. 8, there is shown a retainer  64  that may be used with the coupler of this invention. The retainer is generally a ring-shaped device that, in this described embodiment, attaches to the female portion and includes an annular wall  66 , an outer circumferential wall  68 , and an annular rim  70 . The annular rim extends into a mating annular groove  72  in the outer wall of the female portion near its open end to hold the retainer in place. The annular wall  66  defines an opening  74  which is larger than a cross-section of the neck and smaller than the maximum cross-sectional dimension of the head of the male portion, taken perpendicular to the axis of the male portion, such that the opening is large enough to allow the male portion to be angled relative to the female portion and still allow rotation, while small enough to prevent the head from withdrawing from the socket, thereby preventing decoupling of the coupler.  
         [0020]    The coupler of this invention can be adapted for use in a variety of applications for imparting rotation of one member to another with the axes of the members out of alignment.  
         [0021]    As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto.