Patent Publication Number: US-2022213923-A1

Title: Adjustable tapered washer

Description:
TECHNICAL FIELD 
     The present disclosure is generally related to manufacturing, and, more particularly, mechanical assemblies to facilitate a manufacturing process. 
     BACKGROUND 
     Mechanical assemblies, especially those involving the installation of precision parts or sub-assemblies onto welded structures, often require geometrical angular adjustments or angular alignments. For some agricultural equipment companies, this is especially true with the manufacture or fabrication of multi-rib, V-belt drives, but is not limited to that application. For V-belt drives, a spring-loaded pulley is employed to maintain proper initial tension on a slack-side span between V-grooved driver and driven sheaves. Tensioner pulleys are most often non-grooved on their diameter in contact with the belt. If the pulley axis-of-rotation is perpendicular to the direction of belt travel, then the belt will not deflect and instead run true or square and maintain position on the pulley. If even a small angular misalignment exists between the axis of rotation and a normal or orthogonal direction of the chassis (e.g., hence, not perpendicular), the belt will progressively track in a direction lateral to the direction of travel. If this misalignment is sufficiently large, the belt may jump a groove on the driver and/or driven sheaves, potentially compromising the belt drive. Alignment of a pulley relative to the chassis during the manufacturing process is difficult and time consuming. The same is true for a pulley on the tight-side of a belt drive where alignment is especially important. 
     SUMMARY OF THE INVENTION 
     In one embodiment, a washer assembly, comprising: plural washers adjacent each other, each having a tab and a tapered body of a defined angle, wherein relative adjustment of the tabs corresponds to a composite angle range from zero to twice the defined angle. 
     These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of an adjustable washer assembly and corresponding system of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of an adjustable washer assembly and associated system. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a schematic diagram that illustrates, in fragmentary view, an example environment in which an embodiment of an adjustable washer assembly may be used. 
         FIG. 2  is a schematic diagram that illustrates in fragmentary, cross-sectional view a pulley with and without misalignment to demonstrate an example misalignment and show an example location where misalignment of a pulley during manufacture may be addressed by an embodiment of an adjustable washer assembly. 
         FIGS. 3A-3B  are schematic diagrams that conceptually illustrate the effect of the misalignment, similar to that depicted in  FIG. 2 , on belt tracking issues for which an embodiment of an adjustable washer assembly may be used to compensate. 
         FIGS. 4A-4B  are schematic diagrams that illustrate in fragmentary, rear-isometric and side elevation, cut-away views, respectively, an embodiment of a system that uses an embodiment of an adjustable washer assembly to compensate for the misalignment and belt tracking issues depicted in  FIGS. 2-3B . 
         FIGS. 5A-5C  are schematic diagrams that illustrate in fragmentary, front isometric views, the progressive manufacture of portions of a pulley using an embodiment of an adjustable washer assembly. 
         FIGS. 6A-6C  are schematic diagrams that illustrate in isometric views various configurations of an embodiment of an adjustable washer assembly. 
         FIGS. 7A-7B  are schematic diagrams that illustrate in cross-sectional and front elevation views, respectively, a single washer of an embodiment of an adjustable washer assembly. 
         FIGS. 8A-8B  are schematic diagrams that illustrate in cross-sectional and front elevation views, respectively, an embodiment of an adjustable washer assembly comprising a set of washers. 
         FIG. 8C  is a diagram that illustrates a table defining example face angles based on relative tab angles of an embodiment of an adjustable washer assembly. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Certain embodiments of an adjustable washer assembly and system are disclosed that facilitate the use of geometric angular adjustments or alignments to address misalignment among components of a mechanical system. In one example environment, disclosed herein, the mechanical system comprises a belt drive system having one or more pulleys that are mounted to a chassis. In one embodiment, the adjustable washer assembly comprises plural (e.g., two (2)) identical washers, each of which has a body having a small bevel or taper angle and a tab (or equivalently, an ear or tell-tale handle). When used in sets (e.g., pairs), the relative angular position of the tabs controls a total or composite (face) angle, enabling adjustment between the pulley and the chassis to compensate for misalignment. For instance, at one extreme with tabs opposed, the individual bevel angles cancel each other for a composite angle of zero. Also, at another extreme when tabs are aligned, the composite bevel angle is twice (e.g.,  2   x ) the individual angle. Adjustments may be made at these composite angles or anywhere in between. 
     Digressing briefly, current solutions to misalignment of pulleys relative to the chassis includes disassembling the pulley and grinding a bushing encompassing a pulley shaft, the bushing abutted against the chassis, to introduce a corrective angle, which may consume considerable labor hours; or alternatively, adding a plate that mounts to three threaded rods projecting from the chassis and using pairs of nuts on one or more of the rods to make adjustments to the angle, which adds cost, weight, and consumes space. In contrast, certain embodiments of an adjustable washer assembly provide a simple, low cost solution to such misalignments that also features a thin profile with low space requirements. 
     Having summarized various features of certain embodiments of an adjustable washer assembly of the present disclosure, reference will now be made in detail to the detailed description of an adjustable washer assembly as illustrated in the drawings. While the disclosure is described in connection with these drawings, there is no intent to limit it to the embodiment or embodiments disclosed herein. For instance, though emphasis is placed on an environment comprising belt drives, in some embodiments, an adjustable washer assembly may be used in other applications as an alternative to grinding or complicated, heavy brackets to correct for misalignments in any of a variety of mechanical systems. Further, although the description identifies or describes specifics of one or more embodiments, such specifics are not necessarily part of every embodiment, nor are all various stated advantages associated with a single embodiment. On the contrary, the intent is to cover all alternatives, modifications and equivalents included within the scope of an adjustable washer assembly as defined by the appended claims. Further, it should be appreciated in the context of the present disclosure that the claims are not necessarily limited to the particular embodiments set out in the description. 
     Referring now to  FIG. 1 , shown is a schematic diagram of an example environment  10  in which an embodiment of an adjustable washer assembly may be used. The example environment  10  comprises a belt drive system (e.g., a multi-strand (multi-rib) V-belt drive), which may be used on a combine harvester. The belt drive system may be used to run a shaker mechanism of the combine harvester or for other belt drive tasks on a combine harvester or for driving/guiding a belt on other machines. The belt drive system in this example environment  10  comprises an endless belt  12  whose movement is influenced by a driver sheave  14  on one end and guided by a driven sheave  16  on the other end. The driver sheave  14  and the driven sheave  16  each comprise V-grooves that guide the belt  12 , and are fixed to, and supported by, respective shafts or mounting assemblies (not shown) operably coupled to a chassis. Further, the respective mounting assemblies for the driver sheave  14  and the driven sheave  16  tend to be fairly true (e.g., aligned, squared, orthogonal) with the chassis. In between the driver sheave  14  and the driven sheave  16  is a tensioner pulley  18  and coupled spring-loaded tensioning assembly  20  (e.g., a pivoting or floating tensioning arm, with pivot shaft and spring not shown) on a slack-span of the belt  12 , a fixed position idler pulley  22  on the slack span of the belt  12 , and a fixed position idler pulley on a tight/driving span of the belt  12 , all of which are supported by a chassis. In general, the tensioner pulley  18  and tensioning assembly  20  are configured to provide tension to the belt  12 . The belt tension, along with the magnitude for the belt wrap (angle), results in a reaction force (radial force) applied to the pulley  18  and its supporting structure. The idler pulleys  22  and  24  are configured to guide the belt between the driver sheave  14  and the driven sheave  16 , and are typically comprised of low cost, sheet metal assemblies that are generally not grooved. One or more of the pulleys  18 ,  22 , and  24  tend to be misaligned relative to the chassis (e.g., not true, square or orthogonal to the chassis). That is, a pulley axis of rotation is not square to the direction of belt travel. 
       FIG. 2  illustrates a cross-sectional, side elevation view of the idler pulley  22  with (deflected,  22 A) and without misalignment (undeflected  22 B), which are also shown here to illustrate a location for certain embodiments of an adjustable washer assembly. It should be appreciated by one having ordinary skill in the art that any one or more (e.g., all) of the pulleys  18 ,  22 , or  24  may have misalignment issues during the manufacturing process, and that the selection of the idler pulley  22  is for illustrative purposes, with similar applicability to the other pulleys. The idler pulley  22  also provides a good choice for illustrating how certain embodiments of an adjustable washer assembly compensates for a source or sources of misalignment, given the direction of rotation and the long entry span for this particular idler pulley  22 , as described below. A source of misalignment may be static (e.g., due to manufacturing error) and/or elastic (e.g., due to belt load and lack of stiffness in the supporting structure), and certain embodiments of an adjustable washer assembly may compensate for either or both sources of misalignment. Shown is the belt  12  that is guided along the idler pulley  22  in known manner. Also shown is a chassis  26  to which the belt drive system is mounted. The chassis  26  comprises an opening  28  through which a mounting assembly for the idler pulley  22  is inserted and secured to the chassis  26 . The mounting assembly comprises a shaft  30  that enables rotation of the pulley  22 , the shaft  30  inserted through the opening  28  and mounted to an internal surface of the chassis  26  by a securing member (e.g., nut)  32 . Cylindrically surrounding or enclosing the shaft  30  is a bushing  34 . The bushing  34  is clamped or tightened against the outside or face surface of the chassis  26  via a securing member (e.g., nut)  36  at the end of the shaft  30  opposing the securing member  32 . Also shown are known bearing structures  33  (e.g.,  33 A,  33 B) of the idler pulley  22 . As depicted in  FIG. 2 , there exists a slight misalignment between the pulley  22 A and the chassis  26 , which is revealed by the skewed angle of the pulley  22 A relative to the chassis  26 . Note the comparison between the pulley  22 A with misalignment, and the pulley  22 B without misalignment. The misalignment causes the belt  12  to wander and not track true. In certain embodiments of an adjustable washer assembly, the adjustable washer assembly is arranged between the bushing  34  and the outside surface or face of the chassis  26  to compensate for the misalignment. Stated otherwise, the adjustable washer assembly compensates for the belt force and resultant deflection arising from the misalignment. 
     Explaining misalignment that certain embodiments of an adjustable washer assembly is intended to address, attention is directed to  FIGS. 3A-3B , which conceptually illustrate the effect of a misalignment, similar to that depicted in  FIG. 2 , on belt tracking issues for which an embodiment of an adjustable washer assembly may be used to compensate. In  FIG. 3A , a belt drive system  40 A is shown, with similar functionality to the belt drive system shown in  FIG. 1 . The belt drive system  40 A comprises a driver sheave  42  and a driven sheave  44 , with a tensioner pulley  46 A arranged in between, and an endless belt  48  that is driven or guided among the aforementioned pulleys/sheaves. Referring to the accompany diagram  50  immediately beneath the depiction of the belt drive system  40 A, shown is an overhead, exaggerated representation (exaggerated for illustration) of the misalignment of the tensioner pulley  46 A, similar to that shown in  FIG. 2 , and its effect on belt travel based on certain factors. For instance, the effect of misalignment on belt tracking is a function of the entry span relative to the exit span. Shown in the diagram  50  of  FIG. 3A  is the entering span length (L) between the driver sheave  42  and the tensioner pulley  46 A, and the misalignment of the tensioner pulley  46 A represented by a toe angle error, e (theta). The diagram  50  reveals that, with the misalignment, a long entry span followed by a short exist span (between the tensioner pulley  46 A and the driven sheave  44  in this example) results in a large displacement (z) and a large exiting angle, β (beta), which in turn leads to high potential belt tracking issues. In other words, the belt  48  tends to run perpendicular to the pulley axis of rotation. Thus, in the presence of misalignment, the belt spirals in a direction towards a perpendicular track relative to the axis of rotation, such that the belt  48  may run off track (especially for tensioner pulleys that are unconstrained by the absence of grooves). In particular, because of this long span, the belt  48  goes off center or out of plane a relatively large distance, where recovery occurs over a short span or distance, which tends to cause the belt  48  to run off track. 
     In  FIG. 3B , shown is the belt drive system  40 B with the tensioner pulley  46 B positioned closer to the driver sheave  42 . In this case, and referring to diagram  52  immediately beneath the depiction of the belt drive system  40 B, a relatively shorter entry span (L) is shown compared to the depiction in diagram  50 , and a relatively longer exit span is also shown. In the case of a short entry span plus a long exit span, there is a small displacement (z) and a small exiting angle β (beta), which results in a lower potential for tracking issues. That is, with a short entry span, the belt  48  tends to run perpendicular to the pulley  46 B, but does not travel very far (small z). Thus, recovery is long and fairly gentle (over the long exit span). It is noted that, with the same angle of toe error, the entry span relative to the exit span is an important indicator of the potential for belt tracking issues. Conventional solutions to the misalignment, as indicated above, involved adjustments to the toe angle by grinding components (or by the less labor-intensive act of bending components) of the pulley mounting assembly to induce a corrective angle, which may be a labor-intensive solution. Certain embodiments of an adjustable washer assembly make adjustments to the toe angle in a simpler, more cost-effective way. 
     Referring now to  FIGS. 4A-4B , shown are various cut-away views that demonstrate the arrangement of certain embodiments of an adjustable washer assembly that correct for the misalignment of a pulley, and in this example, the idler pulley  22  (shown in cut-away, without the belt) described in association with  FIG. 2 . It should be appreciated that the adjustable washer assembly may be used with similar applicability to correct or compensate for misalignment for the other pulleys  18  and/or  24  of  FIG. 1 , or for the tensioner pulley  46  of  FIGS. 3A-3B , and that the focus on idler pulley  22  is for illustrative purposes and convenience of explanation. As shown in rear-isometric and side-elevation, cut-away views, respectively, in  FIGS. 4A-4B , the idler pulley  22  is coupled to the chassis  26  via a pulley mounting assembly comprising the shaft  30  that is cylindrically surrounded or enclosed by the bushing  34  and secured to the chassis  26  at each end by securing members  32  and  36 , and the bearing structures  33 A and  33 B, as similarly described above. However, an additional component of the pulley mounting assembly is introduced in  FIGS. 4A-4B  in the form of an embodiment of an adjustable washer assembly  54 . As depicted in  FIGS. 4A-4B , the adjustable washer assembly  54  is arranged at an interface between the bushing  34  and an outside or external (front face) surface of the chassis  26 , and in this embodiment, comprises plural (e.g., a set or pair of) washers that have a tapered or beveled body and that are stacked adjacent each other and arranged or rotated in a manner that provides a composite angle that offsets the toe angle error present due to misalignment of the pulley  22  relative to the chassis  26 . 
       FIGS. 5A-5C  provide a further illustration of various stages of manufacture of certain portions of the pulley mounting assembly using an embodiment of an adjustable washer assembly  54 . Referring to  FIG. 5A , shown is a front face  56  (external or outside surface) of the chassis  26 , with the adjustable washer assembly  54  adjacent to (abutted against) the front face  56  and centered over the opening  28  proximal to a lower portion of the front face  56 . With continued reference to  FIG. 5A , attention is directed also to  FIGS. 6A-6C . The adjustable washer assembly  54  comprises a pair of separate, stacked or adjacent tapered first and second washers  58 ,  60 . Note that in some embodiments, the adjustable washer assembly may have more than two washers. The first tapered washer  58  comprises a round body  62 . Likewise, the second tapered washer  60  comprises a round body  64 . The first tapered washer  58  comprises a tab  66 , and similarly, the second tapered washer  60  comprises a tab  68 . The tabs  66 ,  68  serve both as handles to achieve a relative rotation angle and as a geometric visual reference. In one embodiment, the tabs  66 ,  68  comprise material added to the respective round bodies  62 ,  64 . Also shown in  FIGS. 6A-6C  is a schematic representation  70  of the taper for each washer,  58 ,  60 , and how the collective angle of the taper faces are adjusted based on the relative tab configuration. In  FIG. 6A , the tabs  66  and  68  are exactly aligned (zero degree relative tab angle), resulting in the maximum composite (face) angle (e.g., twice the individual taper angle). In  FIG. 6B , the tabs  66  and  68  are one hundred-twenty (120) degrees apart, resulting in a composite (face) angle of half of the maximum composite angle. In  FIG. 6C , the tabs  66  and  68  are one hundred eighty (180) degrees apart, resulting in a composite (face) angle for the tapered washers of zero (0) degrees. Thus, toe angle errors ranging from large to small are respectively compensated by relative tab angles ranging continuously (anywhere) from zero degrees to one hundred eighty degrees. 
     Note that each washer  58 ,  60  comprises a central opening  72  that enables the shaft  30  to be inserted through the openings  72  and opening  28  (co-aligned with opening  72 ) of the chassis  26 , as depicted in  FIG. 5B .  FIG. 5C  shows the pulley mounting assembly with the bushing  34  cylindrically surrounding the shaft  30  and abutted against the adjustable washer assembly  54  via forces applied to the bushing  34  through adjustment of the securing member  36  acting directly or indirectly (e.g., through another bushing or spacer  74 ) on the bushing  34 . The appropriate spacing of tabs  66 ,  68  needed to compensate for the misalignment (e.g., toe error) is achieved via the resultant composite angle. As shown in  FIG. 5C , the bushing  34  is inserted over the shaft  30  and the adjustable washer assembly  54  is tightened against the chassis  26  via a torque applied to the securing member  36 . 
     Though the adjustable washer assembly  54  is illustrated with washers  58  and  60  having a tapered, round body  62  and  64 , respectively, in some embodiments, the tapered bodies  62 ,  64  may be of another geometry, such as square, hexagonal, etc. In some embodiments, the taper is constrained to the body  62 ,  64 , though in some embodiments, the tabs  66 ,  68  may also be tapered. In some embodiments, the adjustable washer assembly  54  may use plural washers, each of a different body geometry. 
       FIGS. 7A-7B  are schematic diagrams that illustrate in cross-sectional and front elevation views, respectively, a single washer  76  of an embodiment of an adjustable washer assembly. The washer  76  is shown with some example dimensions (in millimeters) for illustrative purposes. It should be understood by one having ordinary skill in the art that these dimensions may differ depending on the particular mechanical system specifications serving as the environment for an embodiment of an adjustable washer assembly. In this example, the washer  76  comprises a tab  78  and round body  80 , the round body comprising a central opening  82  (e.g., round in this example, but not limited to this geometry). In this embodiment, the taper begins at the juncture between the tab  78  and the body  80 , and has an angular dimension of 0.50 degrees. The thickness of the washer  76  at the tab is approximately 1.0 millimeters, with the thickness at the end of the taper at approximately 0.616 millimeters. 
       FIGS. 8A-8B  are schematic diagrams that illustrate in cross-sectional and front elevation views, respectively, an embodiment of an adjustable washer assembly  84  comprising a pair of washers  76 A,  76 B adjacent each other. In one embodiment, the washers  76  ( 76 A,  76 B) are each of the same dimension and shape as the washer  76  depicted in  FIGS. 7A-7B . As shown, the washers  76 A,  76 B are adjacent to each other, with adjustments in the tab angle made to enable adjustments in the composite or face angle, as depicted by table  86  in  FIG. 8C . That is, table  86  proscribes a composite or face angle based on the relative tab angle. For instance, and consistent with the description of tab angles versus face angles described in association with  FIGS. 6A-6C , with the tabs  78 A and  78 B having a relative tab angle of one hundred eighty (180) degrees, the face angle is zero degrees, whereas tab angles of one hundred twenty degrees (as depicted in  FIG. 8B ) and zero degrees (exactly aligned) results in respective face angles of one half and twice the tapered angle (two times 0.50 degrees as shown in  FIG. 7A ). The table  86  further shows the various or continuous gradations in face or composite angle, enabling fine control of angular alignment during final the final stages of manufacture (e.g., final assembly) with full adjustability of taper angle (e.g., anywhere from zero to one degrees in the example depicted in  FIG. 8C ). 
     Certain embodiments of an adjustable washer assembly correct for misalignment during the manufacturing process by enabling continuous, controllable and predictable adjustment of a taper angle. Since the washers are relatively thin, the adjustable washer assembly may be introduced into the manufacturing process without excess dimensional disruption. Further, the shallow angles involved render the tapered washer set self-locking under clamp load such that the angle will not change. Flexibility and/or adaptability is yet another feature, since the composite angle may be re-adjusted as conditions change. In some embodiments, the adjustable washer assembly may be manufactured using a coining or stamping process to keep the manufacturing cost low and simple, though not limited to these types of manufacturing processes. Further, the washers may be manufactured for any range of angular adjustment (e.g., 0-1 degrees, 0-2 degrees, 0-3 degrees, etc.) and may be used in sets or pairs of individual washers or in multiples of three or more in some embodiments. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. Note that various combinations of the disclosed embodiments may be used, and hence reference to an embodiment or one embodiment is not meant to exclude features from that embodiment from use with features from other embodiments. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. Any reference signs in the claims should be not construed as limiting the scope.