Abstract:
A presently-preferred embodiment of a quick-release coupler comprises a housing having a first interior surface defining a center cavity and a second interior surface defining a through hole intersecting the center cavity. The coupler also comprises a locking member at least partially disposed in the center cavity and having a first and an opposing second inwardly facing surface partially defining a central passage in the locking member, and a projection extending partially along a length of the first surface. The locking member is movable between a first position wherein the central passage is adapted to removably receive an end portion of a torque-transmitting shaft, and a second position wherein the projection is adapted to engage a recessed portion of the torque-transmitting shaft and thereby inhibit removal of the end portion from the central passage.

Description:
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Serial No. 60/279,587, which was filed on Mar. 29, 2001 and is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to mechanical couplers. More particularly, the invention relates to a quick-release coupler for mechanically coupling a driving shaft to a driven shaft. 
     BACKGROUND OF THE INVENTION 
     Torque is commonly transmitted between mechanical components by way of a driving shaft that imparts rotational movement to a driven shaft. The driving shaft and the driven shaft are typically joined using some form of mechanical coupler. Such couplers are often used in applications that require frequent coupling and decoupling of the driving shaft and the driven shaft. For example, a typical farm tractor may be used in conjunction with several different types of farming implements in one day, e.g., a plow, spreader, planter, etc. Couplers that permit the driving and driven shafts of these components to be coupled and decoupled quickly, and with minimal effort are therefore highly desirable. 
     So-called “quick-release” couplers have been developed to facilitate the coupling and decoupling of driven and driving shafts on an expedited basis. Such couplers, however, often require multiple steps in the coupling and decoupling process, and necessitate the use of external tooling. Some quick-release couplers also require a time-consuming alignment of the driving and driven shafts. 
     Conventional quick-release couplers may incorporate twist collars to secure the driving and driven shafts. Such couplers, however, are usually large, complex and expensive in relation to other types of couplers. Other types of conventional quick-release couplers may rely on the engagement of a ball and a detent to secure the driving and driven shafts. These types of couplers, in general, do not provide a positive visual indication that the shafts have been properly coupled. 
     In light of the above discussion, it is evident that an ongoing need exists for a simple, compact, and inexpensive quick-release coupler that can be used to couple a driving and a driven shaft with minimal effort, that minimizes the possibility for errors during the coupling process, and that provides a positive visual indication that the shafts have been properly coupled. 
     SUMMARY OF THE INVENTION 
     A presently-preferred embodiment of a coupler for releasably coupling a first shaft and a second shaft comprises a housing having a first interior surface defining a center cavity and a second interior surface defining a through hole intersecting the center cavity. The coupler also comprises a locking member at least partially disposed in the center cavity. The locking member comprises a first and an opposing second inwardly-facing surface partially defining a central passage in the locking member, and a projection extending partially along a length of the first inwardly-facing surface. 
     The locking member is movable between a first position wherein the projection is substantially misaligned with the through hole and the central passage is adapted to removably receive an end portion of the first shaft, and a second position wherein the projection is substantially aligned with the through hole and the projection is adapted to engage a recessed portion of the first shaft and thereby inhibit removal of the end portion from the central passage. 
     A presently-preferred embodiment of a quick-release coupler comprises a housing having a first interior surface defining a center cavity and a second interior surface defining a through hole intersecting the center cavity. The quick-release coupler also comprises a locking member at least partially disposed in the center cavity. The locking member comprises a first and an opposing second inwardly facing surface partially defining a central passage in the locking member, and a projection extending partially along a length of the first surface. The locking member is movable between a first position wherein the central passage is adapted to removably receive an end portion of a torque-transmitting shaft, and a second position wherein the projection is adapted to engage a recessed portion of the torque-transmitting shaft and thereby inhibit removal of the end portion from the central passage. 
     Another presently-preferred embodiment of a coupler for releasably coupling a first shaft and a second shaft comprises a housing comprising a central portion having an interior surface defining a center cavity having an upper portion, a middle portion, and an lower portion. The housing also comprises a flange portion extending from the central portion and having an interior surface defining a through hole. The through hole intersects the middle portion of the center cavity, and is adapted to receive the first shaft. 
     The coupler further comprises a locking member at least partially disposed in the center cavity. The locking member comprises a first and an opposing second inwardly-facing surface partially defining a central passage within the locking member, and a projection extending along the first inwardly-facing surface. The locking member is movable between a first position wherein the projection is located in the lower portion of the center cavity and the central passage is adapted to removably receive the first shaft, and a second position wherein the projection is located in the middle portion of the center cavity and the projection is adapted to engage a recessed portion of the first shaft and thereby inhibit relative movement between the first shaft and the housing. 
     Another presently-preferred embodiment of a coupler for releasably coupling a first shaft and a second shaft comprises a housing comprising a central portion having an interior surface defining a center cavity, and a flange portion extending from the central portion and having an interior surface defining a through hole adapted to receive the first shaft. 
     The coupler further comprises a locking member at least partially disposed in the center cavity and comprising a first inwardly-facing surface having an upper portion and a lower portion, and an opposing second inwardly-facing surface having an upper portion and a lower portion. The locking member also comprises a first projection extending along not more than the lower portion of the first surface, and a second projection extending along not more than the lower portion of the second surface. The locking member is movablebetween a first position wherein an extended centerline of the through hole is located between the upper portions of the first and the second surfaces, and a second position wherein the extended centerline of the through hole is located between the first and the second projections. 
     Another presently-preferred embodiment of a coupler for releasably coupling a first shaft and a second shaft comprises a housing comprising a first interior surfacedefining a center cavity, and a second interior surface defining a through hole adapted to receive the first shaft. The coupler further comprises a locking member at least partially disposed in the center cavity and comprising a first and an opposing second inwardly-facing surface partially defining a central passage having an upper and a lower portion. 
     The locking member also comprises a projection extending along not more than a portion of the first inwardly-facing surface and being located in only the lower portion of the central passage. The locking member is movable between a first position wherein the upper portion of the central passage is substantially aligned with the through hole and is adapted to removably receive an end portion of the first shaft, and a second position wherein the lower portion of the central passage is substantially aligned with the through hole and the projection is adapted to engage a recessed portion of the first shaft and thereby inhibit relative movement between the first shaft and the housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, the drawings show an embodiment that is presently preferred. The invention is not limited, however, to the specific instrumentalities disclosed in the drawings. In the drawings: 
     FIG. 1A is a top perspective view of presently-preferred coupler having an input shaft and a cross shaft coupled thereto, with a locking member of the coupler in an upper position; 
     FIG. 1B is an exploded view of the coupler, the input shaft, and the cross shaft shown in FIG. 1A; 
     FIG. 2A is a cross-sectional side view of the coupler and the cross shaft shown in FIG. 1 taken along the line “A—A” of FIG. 1, with the locking member in the upper position; 
     FIG. 2B is a cross-sectional side view of the coupler and the cross shaft shown in FIGS. 1 and 2A taken along the line “A—A” of FIG. 1, with the locking member in a lower position; 
     FIG. 3A is a cross-sectional side view of the coupler, the input shaft, and the cross shaft shown in FIGS. 1-2B taken along the line “A—A” of FIG. 1, with the locking member in the upper position and engaging the cross shaft; 
     FIG. 3B is a top cross-sectional view of the coupler, the input shaft, and the cross shaft shown in FIGS. 13A, with the locking member in the upper position and engaging the cross shaft, from a perspective rotated ninety degrees from the perspective of FIG. 3A; 
     FIG. 4 is a bottom view of the locking member of the coupler shown in FIGS. 1-3B; 
     FIG. 5 is cross-sectional side view of the locking member shown in FIG. 4, taken along the line “ 5 — 5 ” of FIG. 8; 
     FIG. 6 is top view of the locking member shown in FIGS. 4 and 5; 
     FIG. 7 is bottom perspective view of the locking member shown in FIGS. 4-6; 
     FIG. 8 is side view of the locking member shown in FIGS. 4-7, from a perspective rotated ninety degrees from the perspective of FIG. 5; 
     FIG. 9 is an axial view of the input shaft shown in FIGS. 1A,  1 B,  3 A, and  3 B; and 
     FIG. 10 is a side view of the input shaft shown in FIGS. 1A,  1 B,  3 A,  3 B, and  9 , from a perspective rotated ninety degrees from the perspective of FIG.  9 . 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A presently-preferred embodiment of the invention provides a quick-release coupler for removably coupling a first and a second shaft. A presently-preferred quick-release coupler  10  is depicted in FIGS. 1-10. The figures are referenced to a common coordinate system  8  depicted therein. The quick-release coupler  10  is utilized to releasably couple an input shaft  14  of a tractor to cross shaft  12  of a combine spreader (the input shaft  14  and the cross shaft  12  function as driving and driven shafts, respectively, in this particular arrangement). This particular embodiment is described for illustrative purposes only. The invention can be used in virtually any type of application in which a driving shaft is releasably coupled to a driven shaft. 
     The coupler  10  comprises a housing  20  having a central portion  20   a  and a first flange portion  20   b  extending from the central portion  20   a  (see FIGS.  1 - 3 ). The housing  20  also includes a second flange portion  20   c  extending from an opposite side of the central portion  20   a  as the first flange portion  20   b . The housing  20  includes a first interior surface  20   d  that defines a substantially cylindrical cavity  40  within the main portion  20   a . The cavity  40  includes an upper portion  40   a , a middle portion  40   b , and a lower portion  40   c . An upper end of the cavity  40  is open, i.e., unrestricted, and a lower end of the cavity  40  is defined by a second interior surface  20   e  of the housing  20 . It should be noted that directional terms appearing throughout the specification and claims, e.g. “upper,” “lower,” etc., are used with reference to the component orientations depicted in FIGS. 1B-3B. These terms are used for illustrative purposes only, and are not intended to limit the scope of the appended claims. 
     The housing  20  includes a third interior surface  20   f  that defines a first through hole  34 . The first though hole  34  extends through the first flange portion  20   b  and intersects the center cavity  40 . The first through hole  34  is adapted to receive the input shaft  14  (the input shaft  14  is shown in detail in FIGS.  9  and  10 ). The input shaft  14  and the first through hole  34  of the exemplary embodiment each have a substantially hexagonal cross-section. The invention, however, can be used in conjunction with driving and driven shafts having virtually any type of cross-section, including splined shafts and shafts having substantially square or rectangular cross-sections. Details relating to the coupling of the input shaft  14  and the housing  20  are presented below. 
     The housing  20  includes a fourth interior surface  20   g  that defines a second through hole  36 . The second though hole  36  extends through the second flange portion  20   c  and intersects the center cavity  40 . The second through hole  36  is adapted to receive the cross shaft  12 . The cross shaft  132  is preferably fixed to the housing  20  by a retaining ring  23  secured in place by welding. The cross shaft  12  and the second through hole  36  each have a substantially hexagonal cross-section. 
     The quick-release coupler  10  further comprises a locking member  22 . The locking member  22  is shown in detail in FIGS. 4-8. The locking member  22  is positioned at least partially within the cavity  40  of the housing  20 , and is capable of translating between an upper position (FIGS. 2A and 3) and a lower position (FIG.  2 B). The locking member  22  includes an upper portion  22   a , intermediate portion  22   b , and a lower portion  22   c . The upper portion  22   a  preferably has a rounded upper surface  22   d . In other words, the upper portion  22   a  preferably has a substantially hemispherical shape. The upper portion  22   a  extends upwardly from the central portion  20   a  of the housing  20  when the locking member  22  is in its upper position, as shown in FIGS. 1,  2 A, and  3 A. The intermediate portion  22   b  is substantially cylindrical, and has a vertically-extending slot  42  defined therein. The intermediate portion  22   b  includes a lower surface  22   e.    
     The lower portion  22   c  comprises a first side member  22   f  and a second side member  22   g . The first side member has an inner surface  22   h , and the second side member has an inner surface  22   i  that opposes the inner surface  22   h . The lower portion  22   c  also comprises a bottom member  22   j  having an upper surface  22   k  and a lower surface  221 . 
     The surfaces  22   e ,  22   h ,  22   i , and  22   k  define an internal passage  32  in the locking member  22 . The internal passage  32  has an upper portion  32   a  and a lower portion  32   b  (see FIG.  7 ). 
     The locking member  22  further comprises a first projection  33   a  and a second projection  33   b . The projection  33   a  projects inwardly from the inner surface  22   h  of the side member  22   f . The projection  33   b  projects inwardly from the inner surface  22   i  of the side member  22   g . The projections  33   a ,  33   b  each extend upwardly from the upper surface  22   k  of the bottom member  22   j . The projection  33   a  extends over no more than a portion of the inner surface  22   h , and the projection  33   b  extends over no more than a portion of the inner surface  22   i  so that the projections  33   a ,  33   b  are located exclusively within the lower portion  32   b  of the central passage  32 . 
     The upper portion  32   a  of the central passage  32  substantially aligns with the first through hole  34  in the housing  20  when the locking member  22  is in its lower position, as shown in FIG.  2 B. In other words, an extended centerline C 1  of the through hole  34  extends through the upper portion  32   a  of the central passage  32  when the locking member  22  is in its lower position. 
     The lower portion  32   b  of the central passage  32  and the projections  33   a ,  33   b  are substantially aligned with the through hole  34  when the locking member  22  is in its upper position, as shown in FIGS. 2A and 3A. Hence, the extended centerline C 1  of the through hole  34  is positioned between the projections  33   a ,  33   b  when the locking member  22  is in its upper position. The projections  33   a ,  33   b , when positioned in this manner, prevent the end portion  14   a  of the input shaft  14  from being inserted into the central passage  32  via the through hole  34 . 
     The quick-release coupler  10  further comprises a spring  26 . The spring  26  is positioned within the cavity  40 , between second interior surface  20   e  of the housing  20  and the lower surface  221  of the locking member  22  (see FIGS.  2 A- 3 A). The spring  26  biases the locking member  22  toward its upper position. The quick-release coupler  10  also comprises a pin member  21 . The pin member  21  extends through the slot  42  in the locking member  22 . Opposing ends of the pin member  21  are fixed to the central portion  20   a  of the housing  20  by, for example, pressing the ends into bores defined in the central portion  20   a . The pin member  21  restrains the locking member  22  from rotating in relation to the housing  20 , while permitting the locking member  22  to translate linearly between its upper and lower positions. The pin member  21  also functions as an upper stop for the locking member  22 . 
     Operational details concerning the quick-release coupler  10  are as follows. The, quick-release coupler  10  is adapted for use with a shaft such as the input shaft  14  depicted in FIGS. 9 and 10, as noted previously. The input shaft  14  includes an end portion  14   a  having a recessed portion  14   b  that defines a circumferentially-extending recess  43  (see FIG.  9 ). 
     The input shaft  14  is coupled to the quick-release coupler  10  (and the cross shaft  12 ) by inserting the end portion  14   a  of the input shaft  14  into the first through hole  34  of the housing  20  while the locking member  22  is in its lower position (see FIG.  2 B). The locking member  22  is moved to its lower position by the application of downward force to the upper surface  22   d  of the locking member  22  (the spring rate of the spring  26  is preferably chosen so that the locking member can be moved manually). Movement of the locking member  22  to its lower position causes the upper portion  32   a  of the central passage  32  to substantially align with the through hole  34 . In other words, moving the locking member  22  to its lower position misaligns the projections  33   a ,  33   b  and the through hole  34 , and thereby facilitates the continued insertion of the end portion  14   a  of the cross shaft  12  into the through hole  34 . 
     Continued insertion of the end portion  14   a  into the through hole  34  causes the end portion  14   a  to enter the upper portion  32   a  of the central passage  32 . The continued insertion of the end portion  14   a  eventually causes the recess  43  defined by the input shaft  14  to substantially align with the projections  33   a ,  33   b . Releasing the locking member  22  at this point causes the locking member  22  to translate into its upper position in response to the bias of the spring  26 . The upward translation of the locking member  22  also causes the projections  33   a ,  33   b  to become at least partially disposed within the recess  43 , as shown in FIGS. 3A and 3B. The resulting engagement of the projections  33   a ,  33   b  and the recessed portion  14   b  of the cross shaft  12  restrains the input shaft  14  from axial (x-direction) movement in relation to the locking member  22  and the housing  10 , and thereby couples the input shaft  14  and the cross shaft  12 . (Rotation of the input shaft  14  in relation to the housing  20  is inhibited by the engagement of the hexagonally-shaped input shaft  14  and the matching surface  20   f  of the housing  20 .) 
     The input shaft  14  and the cross shaft  12  are decoupled by applying downward force on the locking member  22  to move the locking member  22  to its lower position. This action moves the projections  33   a ,  33   b  away from the recess  43 , thereby allowing the end portion  14   a  of the input shaft  14  to be withdrawn from the central passage  32  and the through hole  34 . 
     The quick-release coupler  10  thus permits the input shaft  14  and the cross shaft  12  to be coupled and decoupled with one single action, i.e., depressing the locking member  22 . Furthermore, the quick-release coupler  10  has a minimal parts count (three), and can be manufactured without the need for complex machining operations. In addition, the upper portion  22   a  of the locking member  22  protrudes from the housing  20  when the projections  33   a ,  33   b  have engaged the recessed portion  14   b  of the input shaft  14 , thereby providing a positive visual indication that the input shaft  14  has been securely coupled to the cross shaft  12 . This feature, combined with the simple “push-button” operation of the quick-release coupler  10 , minimizes any possibility for errors in the coupling and decoupling processes. 
     It is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of the parts, within the principles of the invention. For example, although the presently-preferred embodiment described herein includes two of the projections  33   a ,  33   b , alternative embodiments may include only one such projection. Also, the shapes of the housing  20  and the locking member  22  are application dependent, i.e., the geometry of the housing  20  and the locking member  22  will vary with the geometry of the driving and driven shafts.