Patent Publication Number: US-2018051430-A1

Title: Snowthrower with adjustable rotor

Description:
Embodiments described herein are directed to snowthrowers and, more particularly, to snowthrowers having a rotor that is adjustable relative to a rotor housing. 
     BACKGROUND 
     It is well known to utilize a snowthrower to collect and eject snow from a ground surface. In general, such snowthrowers are available in either: a two-stage configuration, wherein a low speed rotor collects snow and delivers it to a high-speed impeller for ejection; or a single-stage configuration, wherein a single high-speed rotor both collects and ejects the snow. While variations exist, the rotor of a single-stage snowthrower typically includes one or more helical flytes radially spaced from an axis of the rotor. In addition to snow collection/ejection, the flytes may, in some instances, be used to assist with propulsion of the snowthrower. That is, contact of the flytes with the ground surface during operation may assist in propelling the snowthrower forwardly. 
     While advantageous for assisting in propulsion, contact of the flytes with the ground surface may eventually cause the flytes to wear, effectively reducing the rotor diameter. As the rotor diameter decreases, an excessive gap may develop between the flytes and the rotor housing and/or ground surface. Over time, this gap may reduce the ability of the snowthrower: to effectively collect and eject snow; and/or to effectively propel the snowthrower over the ground surface. 
     SUMMARY 
     In one embodiment, a snowthrower is provided that includes: a rotor housing having spaced-apart first and second sidewalls connected to one another by a rear wall to define a front-facing collection opening; and a rotor positioned within the housing between the collection opening and the rear wall. The rotor includes a rotor shaft having first and second end portions connected to the first and second sidewalls, respectively. The rotor also defines a rotor axis intersecting the sidewalls, wherein the rotor shaft is adapted to rotate, relative to the rotor housing, about the rotor axis. In addition, the rotor has at least one flyte attached to, and radially spaced-apart from, the rotor shaft. Each end portion of the rotor shaft is securable, relative to its respective first or second sidewall, at both a first location and a second location. As the flyte wears during snowthrower operation, the rotor is movable from a first position in which the end portions of the rotor shaft are in their respective first locations, to a second position in which the end portions of the rotor shaft are in their respective second locations. 
     In another embodiment, a snowthrower is provide that includes: a rotor housing with spaced-apart first and second sidewalls connected to one another by a rear wall to define a front-facing collection opening; and a rotor positioned within the housing between the collection opening and the rear wall. The rotor includes: a rotor shaft extending between the first and second sidewalls and defining a rotor axis intersecting the sidewalls, wherein the rotor shaft is adapted to rotate, relative to the rotor housing, about the rotor axis; and at least one flyte attached to, and radially spaced-apart from, the rotor shaft. The snowthrower further includes a coupler connected to the first sidewall and adapted to rotationally support an end portion of the rotor shaft at two or more locations relative to the first sidewall. 
     In yet another embodiment, a snowthrower is provided that includes a rotor housing having spaced-apart first and second sidewalls connected to one another by a rear wall to define a front-facing collection opening. The snowthrower also includes a rotor having a rotor shaft and a radially-offset flyte connected to the rotor shaft, the rotor extending between the first and second sidewalls, wherein the rotor shaft includes a first end portion and a second end portion, the rotor shaft defining a rotor axis that intersects each of the first and second sidewalls. An arm is provided and pivotally connected to the first sidewall at a pivot joint, wherein the arm includes a rotor joint adapted to rotationally support the first end portion of the rotor shaft. The arm is pivotable about the pivot joint between a first position and a second position. 
     The above summary is not intended to describe each embodiment or every implementation. Rather, a more complete understanding of various illustrative embodiments will become apparent and appreciated by reference to the following Detailed Description of Exemplary Embodiments in view of the accompanying figures of the drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWING 
       Exemplary embodiments will be further described with reference to the figures of the drawing, wherein: 
         FIG. 1  is a perspective view of a snowthrower according to embodiments of the present disclosure, the snowthrower including a rotor housing in which is located a rotor; 
         FIG. 2  is a partial, front elevation view of the rotor housing and rotor of  FIG. 1 ; 
         FIGS. 3A and 3B  (collectively referred to as “ FIG. 3 ”) are partial cross-sectional views, wherein:  FIG. 3A  is taken along line  3 - 3  of  FIG. 2 : and  FIG. 3B  is an enlarged view of a portion of  FIG. 3A ; 
         FIG. 4  is a partial, exploded perspective view of a rotor housing and rotor in accordance with embodiments of the present disclosure; 
         FIG. 5  is an enlarged perspective view of a portion of an exemplary rotor housing illustrating a first (e.g., left) rotor coupler; 
         FIG. 6  is an interior-side elevation view of the rotor housing and first rotor coupler shown in  FIG. 5 ; 
         FIG. 7  is an interior-side elevation view similar to  FIG. 6 , but with the first rotor coupler removed; 
         FIG. 8  is an exterior-perspective view of another portion of an exemplary rotor housing illustrating a second (e.g., right) rotor coupler; 
         FIG. 9  is an exterior-side elevation view of the rotor housing and second rotor coupler shown in  FIG. 8 ; 
         FIG. 10  is an exterior-side elevation view similar to  FIG. 9 , but with the second rotor coupler removed; 
         FIG. 11  is a diagrammatic side elevation view (with some structure removed) illustrating rotor axis movement relative to other portions of the rotor housing and drive system according to an exemplary embodiment of this disclosure; 
         FIG. 12  is an exterior-side elevation view (with some structure removed) of a rotor housing incorporating a rotor drive system in accordance with embodiments of the present disclosure, the drive system shown in a disengaged or idle position; and 
         FIG. 13  is an exterior-side elevation view similar to  FIG. 12 , but with the drive system shown in a fully engaged or drive position. 
     
    
    
     The figures are rendered primarily for clarity and, as a result, are not necessarily drawn to scale. Moreover, various structure/components, including but not limited to fasteners, electrical components (wiring, cables, etc.), and the like, may be shown diagrammatically or removed from some or all of the views to better illustrate aspects of the depicted embodiments, or where inclusion of such structure/components is not necessary to an understanding of the various exemplary embodiments described. The lack of illustration/description of such structure/components in a particular figure is, however, not to be interpreted as limiting the various embodiments in any way. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the drawing which form a part hereof. It is to be understood that other embodiments, which may not be described and/or illustrated herein, are certainly contemplated. 
     All headings provided herein are for the convenience of the reader and should not be used to limit the meaning of any text that follows the heading, unless so specified. Moreover, unless otherwise indicated, all numbers expressing quantities, and all terms expressing direction/orientation (e.g., vertical, horizontal, perpendicular, parallel, etc.), in the specification and claims are understood as being modified by the term “about.” 
     Single-stage snowthrowers are a cost-effective solution in many snow removal applications. However, single stage snowthrower rotors are typically subject to wear due to repeated contact with the ground surface during operation. Once wear has reached a threshold condition, rotor service may be needed. With some snowthrower configurations (e.g., those having flytes that are generally straight and parallel to an axis of the rotor), service may involve radially repositioning the flytes relative to the shaft. This procedure, however, does not lend itself well to helical flytes as the helix angle may make accurate adjustment difficult. Accordingly, once a helical flyte rotor is worn sufficiently, it is often replaced. 
     Embodiments of the present disclosure seek to delay helical rotor replacement by providing an adjustment system that allows the operator to accurately and easily adjust the position of the entire rotor (including the rotor shaft) relative to the rotor housing. As a result, as rotor wear occurs, the position of the entire rotor may be adjusted downwardly to maintain desirable positioning of the rotor flytes relative to the ground surface/rotor housing. 
     While embodiments of this disclosure are directed to addressing snowthrower rotor wear, such an application is not limiting. Rather, any application using a rotor contained within a rotor housing may benefit from embodiments of the present disclosure. 
     With reference to the figures of the drawing, wherein like reference numerals designate like parts and assemblies throughout the several views,  FIG. 1  illustrates a variable speed, self-propelled, single stage snowthrower  100  in accordance with embodiments of the present disclosure. Again, while so described and illustrated, such a construction is not limiting as aspects of the depicted/described embodiments may find application to other types of snowthrowers (e.g., two-stage) as well as to other types of power rotor and auger equipment. 
     It is noted that the term “comprises” and variations thereof do not have a limiting meaning where used in the accompanying description and claims. Further, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably herein. Moreover, relative terms such as “left,” “right,” “front,” “fore,” “forward,” “rear,” “aft,” “rearward,” “top,” “bottom,” “side,” “upper,” “lower,” “above,” “below,” “horizontal,” “vertical,” and the like may be used herein and, if so, are from the perspective of one operating the snowthrower  100  while the snowthrower is in an operating configuration (unless noted otherwise), e.g., while the snowthrower  100  is positioned such that wheels  106  and scraper  205  rest upon a generally horizontal ground surface  103  as shown in  FIG. 1 . These terms are used only to simplify the description, however, and not to limit the interpretation of any described embodiment. 
     The terms “coupled,” “attached,” “connected,” and the like refer to elements being attached to each other either directly (in direct contact with each other) or indirectly (having one or more elements between and attaching the two elements). Moreover, “rotationally support” is used herein to describe a relationship in which a first element supports a second element such that the second element may rotate or pivot (e.g., about an axis) relative to the first element. 
     As illustrated in  FIG. 1 , the snowthrower  100  may include a chassis or frame  102  supporting a power source or prime mover, e.g., internal combustion engine  104 . One or more (e.g., a pair) of ground support members, e.g., first and second wheels  106 , may be coupled to the frame  102  as shown (e.g., one at or near each of a first (e.g., left) and second (e.g., right) side of the frame  102  (only left wheel  106  is visible in  FIG. 1 , but right wheel  106  is shown in  FIG. 3A ). The wheels  106  may be passive or, alternatively, powered (e.g., by the engine  104 ) to assist with propelling the snowthrower  100  over the ground surface  103 . While described and illustrated herein as using an internal combustion engine, other prime movers (such as an electrical motor) are also contemplated. 
     The snowthrower  100  may include a rotor housing assembly  200  attached to, or integrally formed with, the forward portion of the frame  102 . Among other components, the rotor housing assembly  200  may include a snow-engaging rotor  204  contained within a rotor housing  202 , the latter defining a partially enclosed volume such that the rotor housing may at least partially surround/enclose the rotor. Lowermost portions of the housing  202  (e.g., a scraper  205 ), together with the wheels  106  and the rotor  204 , may form ground contact portions of the snowthrower  100 . 
     The housing  202  may define a collection opening  206  positioned forward of the rotor  204 . The rotor is configured, as described in more detail below, for rotating (e.g., when powered by the engine  104 ) within, and relative to, the housing  202  about a transverse or rotor axis  210 . The housing  202  may include a pair of spaced-apart sidewalls (e.g., (first or left sidewall  212  and a second or right sidewall  214 ) connected to one another by a rear wall  216  (see  FIG. 2 ) such that the rotor housing forms the generally front-facing collection opening  206  and the partially enclosed volume or chamber containing the rotor  204 . In some embodiments, the rear wall  216  may also form an upper wall of the housing while, in other embodiments, a discrete upper wall may be provided. Regardless of the wall configuration, the rotor may be positioned between the collection opening  206  and the rear wall  216  as shown in  FIGS. 1 and 2 . During operation, the snowthrower  100  may move forwardly (e.g., in a direction parallel to a longitudinal axis  105  of the snowthrower) such that snow enters the collection opening  206  and is ejected as described below. 
     As used herein, “longitudinal axis” or “longitudinal direction” refers to a long axis or direction of the snowthrower  100 , e.g., the centerline longitudinal axis  105  extending in the travel or fore-and-aft direction as shown in  FIG. 1 . “Transverse” or “transverse axis” refers to a direction or axis extending side-to-side, e.g., a horizontal axis that is normal or transverse to the longitudinal axis  105  of the vehicle like the rotor axis  210 , the latter which may intersect the sidewalls  212 ,  214  as illustrated. 
     The housing assembly  200  may further include a discharge opening or outlet  217  and a chute assembly  219 . The chute assembly  219  may include a discharge conduit or chute  218  attached to the housing  202  such that a lower end of the discharge chute fluidly communicates with the discharge outlet  217  formed in the housing  202 . Accordingly, the chute  218  may communicate with the partially enclosed volume of the housing  202  and, thus, with the open-face collection opening  206 . 
     The chute  218  may be configured to rotate relative to the rotor housing  202 , e.g., about a chute axis  225  (see  FIG. 2 ). As the rotor  204  rotates within the housing  202 , snow is collected and forcefully ejected through the chute assembly  219 . The chute assembly may be rotated relative to the rotor housing  202  to discharge snow to the left or to the right (or a direction (e.g., front) in between). The chute assembly  219  may, in some embodiments, also include an adjustable deflector  220  near an upper end of the chute  218 . The deflector may pivot about an axis  224 , e.g., via a handle  221  (see  FIG. 1 ), to alter a trajectory of the ejected snow. Of course, such a chute and chute control mechanism are exemplary and other embodiments are certainly possible. 
     As further illustrated in  FIG. 1 , the exemplary snowthrower  100  may include an upwardly and rearwardly extending, generally U-shaped handle assembly  300  having a lower end that is secured to the frame  102 . The handle assembly  300  may form an operator control area having a handlebar  306  that provides controls to an operator located in a walk-behind position. For example, the control area may include a rotor control device (e.g., a hand-operated lever or bail  302 ), and a chute rotation control  304 . The bail  302  may pivot about a transverse pivot axis between a disengaged position (as shown), wherein the rotor  204  is disengaged or de-coupled from the engine  104 , and an engaged position (not shown, but squeezed against the handlebar  306 ), wherein the rotor is engaged or coupled to the engine for rotation about the rotor axis  210 . The chute rotation control  304  may, in the illustrated embodiment, be configured as a sliding handle that displaces a cable attached to the chute assembly  219  to cause the chute assembly to rotate about the chute axis  225  (see  FIG. 2 ). Again, while the control  304  is described with some particularity, such a configuration is exemplary only and other embodiments may incorporate different controls with departing from the scope of this disclosure. 
     With reference to  FIGS. 2, 3A, and 3B , the rotor  204  may include a rotor shaft  211  extending between the sidewalls  212 ,  214 . The rotor shaft  211  is configured to rotate, within the housing  202 , about the transverse rotor axis  210 . Attached to, and moving in unison with, the rotor shaft  211  (via flyte supports  213 ) is one or more flytes  207  radially spaced-apart from the shaft  211 /axis  210 . Each of the flytes  207  may include outboard helical portions (helical flytes  208 ) for collecting snow, and flat or cupped central ejection portions or paddles  209  for ejecting snow. As shown in  FIG. 2 , the rotor  204  and rotor housing  202  may thus define snow collecting portions  226  (associated with the helical flytes  208 ) and a snow ejecting portion  228  (associated with the paddles  209 , which may also contribute to snow collection). 
     Due to their helix angle, the flytes  208  may move snow (during operation) that enters the collection opening  206 , along the rotor axis  210 , toward the paddles  209 . The paddles  209  may be configured to not only collect snow, but also to eject that collected snow (and that snow collected by the helical flytes  208 ) upwardly through the discharge outlet  217 . That is, the helical flytes move collected snow transversely toward the paddles  209 , which then forcefully eject the snow upwardly along the rear wall  216  of the rotor housing  202  and into the discharge outlet  217 , where it is directed by the chute assembly  219  away from the snowthrower  100 . In at least the illustrated embodiments, the rear wall  216  follows or accommodates the contour of the outermost radial edge of the rotor  204  as indicated in  FIGS. 3A-3B . 
     While the helical flytes  208  and the ejection paddles  209  may serve somewhat different functions during operation of the snowthrower  100 , the term “flyte  207 ” may be used herein to encompass both of these elements of the rotor  204 . That is to say, the term flyte  207  is understood, unless otherwise indicated, to include both the helical flytes and the ejection paddles. Moreover, while illustrated with some specificity, rotors having different flyte configurations are certainly contemplated. That is, embodiments of the rotor described and illustrated herein are exemplary only. 
     In addition to collecting and ejecting snow, the rotor  204 , e.g., the flytes  207 , may also assist with propulsion of the snowthrower. As a result, in some embodiments, at least the outermost portions of the flytes  207  may be made of a flexible (e.g., elastomeric) material that can withstand repeated ground impacts during operation. By ensuring some minimal level of contact of the edges of the flytes  207  with the ground surface, rotation of the rotor  204  may urge the snowthrower forwardly. In some embodiments, the assistance provided by the rotor  204  may be altered by application of upward or downward force applied by the operator to the handlebar  306  (see  FIG. 1 ). 
     Over time, contact between the flytes  207  and the ground surface may cause the outermost radial edges of the flytes  207  to wear, effectively reducing the rotor diameter. As this occurs, engagement of the rotor with the ground surface may lessen, reducing the ability of the rotor to provide propulsion assistance. Moreover, as shown in  FIG. 3B , reduction in the rotor diameter may cause a gap  215  between the flytes  207  and the rear wall  216  to form and/or increase. When this gap  215  gets sufficiently large, the ability of the snowthrower  100  to effectively eject snow through the chute assembly  219  may be adversely impacted. 
     Snowthrowers utilizing non-helical or “straight” flytes may address rotor wear by allowing the operator to loosen the flytes  207  and radially move the flytes outwardly relative to the flyte supports  213 /shaft  211 . Once the flytes  207  are correctly positioned, they may again be secured relative to the flyte supports  213 . While effective for straight flytes, such an adjustment technique is problematic for flytes of helical design as it is difficult to maintain the desired gap  215  along the non-linear shape of such flytes. 
     To address this issue, embodiments of the current disclosure may permit the entire rotor  204  (including the shaft  211 , flyte supports  213 , and flytes  207 ) to move relative to the rotor housing  202  to adjust the gap  215  as the rotor wears. Exemplary embodiments of a snowthrower  100  that provides such adjustment is now described with initial reference to  FIG. 4 . 
       FIG. 4  illustrates the exemplary rotor  204  and other select components exploded from the rotor housing  202 . As shown in this view, the flytes  207  may be secured to the flyte supports  213 , e.g., with fasteners or the like, and the flyte supports  213  may be secured to the rotor shaft  211  via most any acceptable manner e.g., fastened, welded, etc. In fact, most any method of joining the flytes  207  to the shaft  211  that allows the components to rotate together is contemplated within the scope of this disclosure. 
     As shown in  FIG. 4 , the rotor shaft  211  may include a first end portion  230  and a second end portion  229  (see  FIG. 8 ) that are operatively secured relative to the sidewalls  212  and  214 , respectively. For example, in some embodiments, the first end portion  230  may extend through an opening  232  formed in the sidewall  212  of the housing  202  and be journaled for rotation relative to the sidewall, e.g., with bearings  231  or the like. The opposite or second end portion  229  of the rotor shaft  204  (see also  FIG. 8 ) may be similarly journaled for rotation through an opening  232  in the sidewall  214  (see also  FIG. 10 ). The first end portion  230  may include features, e.g., splines or a keyway, that allow mechanical coupling of the first end portion to a rotor sheave or pulley  234  located on an outboard side of the sidewall  212 . As a result, when the rotor pulley  234  is powered by the engine  104 , the rotor  204  may rotate. 
     As further described below, the end portions  230 ,  229  (see  FIG. 8 ) of the rotor shaft  211  may be secured, relative to the respective sidewalls  212 ,  214  at both a first location and a second location. As a result, as the flytes  207  wear during snowthrower operation, the rotor  204  may be movable, relative to the rotor housing  202 /sidewalls  212 ,  214 , from a first position in which the end portions of the rotor shaft are each in their first locations, to a second position in which the end portions of the rotor shaft are each in their second locations. 
     In some embodiments, the rotor shaft  211  may be rotationally supported or journaled to a first coupler at the first end portion  230 , wherein the first coupler is connected to the sidewall  212 . An exemplary embodiment of the first coupler is shown in more detail in  FIGS. 5 and 6  (rotor  204  removed from these views) and described below. As used herein, the term “coupler” includes any device or interface technique that accommodates adjustable attachment of the rotor  204  to the snowthrower housing  202 , e.g., to the sidewalls  212 ,  214 . 
     While not wishing to be bound to any specific coupler configuration, the first coupler may, in some embodiments, define an arm  236  that pivotally connects to an inside face of the first sidewall  212  (e.g., between the first and second sidewalls) via a pivot joint  238  defining a pivot axis  240  that may be parallel to the rotor axis  210 . As used herein, the term “pivot joint” may refer to a structure that allows two parts to pivot or rotate about an axis relative to one another. Pivot joints may incorporate various components, e.g., shafts, sleeves, bearings, bushings, etc. as are known in the art. 
     The arm  236  may further define a rotor joint  242  to receive and rotationally support the first end portion  230  of the rotor shaft  211  in two or more locations relative to the sidewalls. In some embodiments, the rotor joint  242  may define a receptacle that accommodates the bearing  231  that may, in turn, support the rotor shaft for rotation about the rotor axis  210 . As a result, the rotor joint  242  may receive the first end portion  230  of the rotor shaft  211  such that the arm  236  rotationally supports the rotor shaft  211 . 
     The arm  236  may further define a guide configured to, for example, limit and/or control pivotal movement of the arm  236  about the pivot axis  240 . In some embodiments, the guide is configured as an elongate aperture or slot  244 . For example, the slot  244  may be arcuate in shape. Moreover, the slot  244  may be defined by a radius  245  having, as its center, the pivot axis  240  of the pivot joint  238 . For reasons that will become apparent, the guide, e.g., slot  244 , may have associated therewith various indexing features such a notches  246 . While illustrated as physical notches  246 , other indexing features, e.g., indicia, other recesses, detents, etc. are certainly possible without departing from the scope of this disclosure. 
     The arm  236  may optionally include a brake mount  248 . As further explained below, the brake mount may rotationally (pivotally) support a brake member  250  (see  FIG. 4 ) located on the outer side of the sidewall  212  such that movement of the arm  236  results in corresponding movement of the brake mount. The brake member  250  may interact with the drive system (described below) to provide braking to the rotor  204 . 
       FIG. 7  is a view similar to  FIG. 6 , but with the arm  236  removed to illustrate corresponding features of the sidewall  212 . As shown in this view, the sidewall may include the opening  232 . The opening  232  may be sized to accommodate a flange  252  of the arm  236  (see  FIG. 4 ). While illustrated as an arcuate slot in  FIGS. 4 and 7  (having its arc center at the pivot axis  240 ), such a construction is not limiting. That is, the opening  232  may have other shapes (e.g., round, oval) without departing from the scope of this disclosure. A similar opening  253  may be provided to accommodate the brake mount  248 . Again, while shown as forming an arc-shaped slot about the pivot axis  240 , the shape of the opening  253  could take many forms. 
     The sidewall  212  may further include a hole  254 . The hole  254  may accommodate the components of the pivot joint  238  to allow pivotal movement of the arm  236  relative to the sidewall  212 . An opening  256  may also be provided in the sidewall  212  to allow interaction with the slot  244  of the arm  236  as further described below. 
     With reference now to  FIGS. 8-10 , the coupling of the second opposite end portion  229  of the rotor shaft  211  with the second or right sidewall  214  will be described. In general, the right side utilizes a second coupler, e.g., arm  237 , adapted to rotationally support the second end portion  229  in a manner similar to the arm  236 /end portion  230  already described herein. For example, the arm  237  may include a pivot joint  238  configured to allow the arm  237  to pivotally connect to the second sidewall  214  such that it is pivotable about a pivot axis that may, in some embodiments, be the same as (coaxial with) the pivot axis  240 . The arm  237  may further include a guide, e.g., opening or slot  244  defined by a radius (see, e.g., radius  245  of  FIG. 6 ) about the pivot axis  240 , and a rotor joint  242  to permit rotationally supporting the second end portion  229  of the rotor shaft  211  with the arm. The slot  244  and/or the sidewall  212  may also include indicators, e.g., indicia and/or notches  246 , to assist with setting the rotor location, i.e., the end portion position, at two or more locations. 
     Unlike the arm  236 , however, the arm  237  may exclude a brake mount as the drive system (described below) is associated, in one embodiment, with only the left side of the snowthrower  100 . While the arm  237  is shown attached to an outside or exterior side of the right sidewall  214 , it could, in other embodiments, be connected to the inner or interior side in a manner similar to the arm  236 . To accommodate exterior side mounting, some embodiments of the snowthrower housing  200  may form a recess or depression  258  as shown in  FIG. 8 . The recess accommodates the arm  237  within the transverse width defined by the rotor housing (see, e.g.,  FIG. 2 ). 
     As shown in  FIG. 10 , the second or right sidewall  214  may also include features similar to the left sidewall  212  illustrated in  FIG. 7 . For example, the right sidewall may include the openings  254 ,  232 , and  256 , the purposes of which have already been described herein with respect to the first or left sidewall  212 . 
     An exemplary method for adjusting rotor position relative to the rotor housing is now described with reference to  FIGS. 4-11 . This exemplary method will refer to adjustments taking place on the left side of the snowthrower (e.g., via movement of the arm  236 ). As the adjustment procedure for the right side is sufficiently similar, a separate description of an exemplary right adjustment procedure is not presented herein. 
     As already stated, during typical snowthrower operation, the flytes  207  may eventually wear. To maintain snowthrower performance, the operator may adjust the rotor in accordance with embodiments of this disclosure. The snowthrower may, in some embodiments, provide objective indicators for determining when rotor adjustment may be beneficial. For instance, one or more areas of the flytes may include wear indicia, e.g., marks or holes  260  (see  FIG. 4 ) near an outer perimeter edge of the flyte, that indicate the extent of flyte wear. For instance, each flyte may include a hole  260  spaced-apart from an outer peripheral edge of the flyte. The hole may be located at a predetermined offset (e.g., 0.1 to 0.2 inches) from the peripheral edge. When the flyte has worn down such that its outer peripheral edge is at or near the outermost hole  260 , the operator may undertake the rotor adjustment process. Other non-limiting examples of wear indicia (in addition to the holes  260 ) include markings, indentations, or any other feature that may be used to indicate rotor radius. 
     In some embodiments, additional holes  260  may be provided that are radially and inwardly offset from the outermost hole  260  to provide an indicator of when the adjustment procedure should be undertaken again. Accordingly, the wear indicia may be configured as indicators located on different concentric circles about the rotor axis  210 . Such multiple wear indicia may be evenly spaced (e.g., every 0.1 inches) along a radial line from the rotor axis  210 , or could be unevenly spaced depending on predicted wear characteristics of the flytes  207 . 
     To adjust the rotor, the operator may turn off or otherwise disable operation of the snowthrower  100 , e.g., turn off the engine  104 . A nut  262  associated with the slot  244  (see  FIGS. 5 and 6 ) may then be loosened (e.g., from a fastener  263  that is, in one embodiment, retained against motion by engagement of a shoulder of the fastener with an interior shape (e.g., square) of the opening  256  of the sidewall  212  (see  FIG. 7 )). In some embodiments, the nut  262  may secure a washer  264  against the arm  236 . The washer  264  may include a shaped protrusion  266  that may fit within one of the notches  246  formed on the arm  236  near the slot  244 . For example, the notches  246  may each define an elongate, V-shaped slot as shown in  FIG. 5 , while the washer  264  includes a complementary V-shaped protrusion that is received in one of the notches  246 . When the nut  262  is tightened, the engagement of the V-shaped protrusion  266  with the V-shaped notch  246  may assist in maintaining the arm  236 / 237  in one of two or more (e.g., three) discrete positions. Of course, while described as complementary V-shaped features, most any feature that provides positive retention of the arm  236 / 237 , with or without discrete positioning, is possible without departing from the scope of this disclosure. 
     With both the nuts  262  (on arms  236  and  237 ) loosened, the rotor  204  may be moved until the protrusion  266  (see  FIG. 5 ) is aligned with the next lowest notch  246 . When both sides are moved to this next notch, the nuts  262  may be re-tightened and snowthrower operation may continue. Accordingly, the engagement of the fasteners with the respective slots of the arms  236 ,  237  may define the available locations of the rotor shaft  211 . 
     In some embodiments, the snowthrower may provide three notches  246  corresponding to three separate locations of the end portions of the rotor shaft (and, correspondingly, three separate positions of the rotor  204 ). During manufacture, the rotor may be designed such that the arms  236 ,  237  are set in their highest notch. Upon wearing to the first indicator (e.g., first hole  260 ), the operator may lower the arms/rotor to the second notch. After subsequently wearing to the second indicator hole  260 , the operator may again lower the arms/rotor to the third and lowest notch. While described with three discrete notches  246  and two corresponding holes  260 , most any number of notches and/or wear indicia are possible without departing from the scope of this disclosure. For example, other embodiments may provide arms movable between two positions, or arms that are infinitely adjustable, without departing from the scope of the disclosure. In some embodiments, corresponding indicia  243  (e.g., numbers or letters as shown in  FIG. 5 ) may be provided on both sidewalls  212 ,  214  to assist with maintaining the rotor axis in the desired level orientation. 
     By allowing movement of the entire rotor  204  relative to the rotor housing  202 , adjustment of the rotor may be achieved without the potential variability in flyte position that may occur when the flytes are radially adjusted relative to the rotor shaft. Moreover, rotor adjustment in accordance with embodiments of the present disclosure may be achieved with a simple and straightforward action, e.g., loosening of the nut  262  on each side of the rotor housing. 
       FIG. 11  illustrates a diagrammatic external side elevation view of the left sidewall  212  (with some structure (belt cover, pulleys, etc.) removed) in accordance with one exemplary embodiment of this disclosure. As shown in this view, the adjustment system may be configured such that, when the arm  236  (and  237 ) is in the middle notch  246 , the rotor axis  210 , the pivot axis  240 , and an axis  110  of the engine  104  drive shaft  108  lie on a common plane or line. Such a construction may minimize the resultant change in spacing between the drive shaft axis  110  and the rotor axis  210  as the arm  236  moves through its various positions (e.g., notches). In the illustrated embodiments, the rotor and snowthrower may be designed so that, when the rotor is new, the arms  236 ,  237  are initially secured in their lowest notches (highest arm/rotor axis position, see  FIG. 5 ) to allow for two subsequent adjustments to occur as the new rotor wears. 
     As further shown in  FIG. 11 , the arm  236  may pivot about the axis  240  between its various rotor height settings. While shown as pivoting about the axis  240 , other embodiments may pivot about a different axis without departing from the scope of this disclosure. For instance, the arm  236  (and  237 ) could extend rearwardly sufficiently to permit the arm to pivot about an axis coincident with the drive shaft axis  110 . 
       FIG. 11  further illustrates movement of the rotor shaft  210  within the opening  232 , and containment of arm movement by the engagement of the fastener  263  within the slot  244 , and movement of the brake mount  248  within the slot  253 . 
       FIGS. 12-13  further illustrate an exemplary drive system  270  for the snowthrower  100  in accordance with embodiments of the present disclosure. In particular,  FIG. 12  illustrates the drive system  270  (e.g., idler pulley  274 ) in a disengaged position or idle mode (i.e., belt slack such that the rotor is not engaged with the engine  104 ), and  FIG. 13  illustrates the drive system in a fully engaged position or drive mode (i.e., belt tensioned such that the rotor receives power from the engine). 
     In some embodiments, the first end portion  230  of the rotor shaft  211  (see also  FIG. 4 ) may, as already described herein, be coupled to the rotor pulley  234 . Similarly, a drive shaft pulley  268  may be connected to the engine drive shaft  108 . An endless drive member, e.g., belt  271 , may then extend about the pulleys  234  and  268  as shown in  FIG. 12  such that, when the belt is sufficiently tensioned, driving power may be transmitted from the engine to the rotor. 
     To control belt tension, an idler member  272  rotationally supporting the idler pulley  274  may be pivotally connected to the snowthrower  100  (e.g., at or near the sidewall  212 ) at a pivot joint  276 . Moreover, to provide a braking force when the drive system is in the disengaged position shown in  FIG. 12 , the brake member  250  may be provided and pivotally connected about the brake mount  248 . In some embodiments, the brake member  250  is connected to the idler member, e.g., the brake member may define a slot  278  in which is received a pin  280  of the idler member  272  to form a sliding connection. 
     When the bail  302  is in the disengaged position as shown in  FIG. 1 , the idler member  272  is biased by a spring (not shown) toward the disengaged position shown in  FIG. 12 . In other words, the idler member  272  is biased in a counterclockwise position about the pivot joint  276 . Due to the biasing force applied to the idler member  272 , the pin  280  applies a downward force to the slot  278  of the brake member  250 , causing the brake member to pivot clockwise about the brake mount  248 . As a result, a brake shoe  282  associated with the brake member may contact and apply a force against the belt  271  to both: slow the belt (and thus the rotor  204 ) when transitioning the drive system from the engaged to the disengaged position; and immobilize the rotor when the drive system is in the disengaged position. 
     When the bail  302  is moved to its engaged position against the handlebar  306  (not shown), an actuating force is provided to the idler member  272 , e.g., by an interconnecting cable  308  (see  FIG. 1 ), causing the idler member to pivot clockwise about the pivot joint  276  to the position shown in  FIG. 13 . As this occurs, the idler pulley  274  is forced against the belt  271 , causing the belt to tension around the drive shaft pulley  268  and the rotor pulley  234 . Once sufficiently tensioned, rotational power is transmitted to the rotor pulley and the rotor rotates. 
     As the idler member  272  pivots in the clockwise direction in  FIG. 13 , the pin  280  may apply an upward force to the slot  278 , causing the brake member  250  to pivot in a counterclockwise direction about the brake mount  248 . As a result, the brake shoe  282  may lift away or otherwise be spaced-apart from the belt  271  as shown. 
     By providing the brake mount  248  on the movable arm  236 , a constant distance between the rotor axis  210  and the brake mount  248  is maintained. Accordingly, as the arm  236  is repositioned to adjust the rotor  204 , the brake mount  248  may also be repositioned, e.g., along the slot  253  (see  FIG. 7 ) formed in the sidewall  212 . In this manner, as the rotor  204  is repositioned, the relative positions of the brake shoe  282  and the belt  271  near the rotor pulley  234  may be maintained to provide a consistent braking force between each rotor adjustment position. Moreover, by connecting the idler member  272  and the brake member  250  via the pin  280  connection, adjustment of the rotor position has little or no effect on idler pulley  274  position. That is to say, the rotor position may be adjusted without requiring any adjustment to the drive system. 
     While adjustment of the rotor may alter the linear distance between the drive shaft axis  110  and the rotor axis  210 , the change is sufficiently small as to be accommodated by movement of the idler member. 
     While illustrated as a pivoting arm, other embodiments may utilize couplers having different configurations. For example, each coupler may form a member that rotationally supports the rotor and attaches to the snowthrower (e.g., to the sidewalls) such that the coupler may translate relative to its respective sidewall (e.g., using adjustment or “jack” screws or the like). 
     In other embodiments, the rotor shaft could merely be an array of indexed holes in each of the sidewalls to which the ends of the rotor shaft may selectively bolt. Alternatively, the sidewalls could each include a slot in which ends of the rotor shaft may be selectively positioned and secured. Accordingly, it is contemplated that some embodiments may not require the use of a coupler, but rather accommodate operative connection directly with the sidewalls. Such configurations may be adapted to function with the belt drive systems shown herein, as well as with systems utilizing a direct drive power source (e.g., an electric motor attached directly to the rotor shaft). 
     In still other embodiments, the adjustment process may be partially or fully automated. For example, the rotor could be biased toward the rear wall of the housing, but retained in one of two or more angled slots associated with each sidewall. As the rotor wears, the biasing force may cause the rotor to eventually escape one notch and fall into the adjacent notch corresponding to the next adjusted position of the rotor. Such a configuration may reduce operator involvement with the rotor adjustment process. 
     As one may appreciate, embodiments of the present disclosure may provide a snowthrower with a rotor that may be easily adjustable to account for wear of rotor flytes over time. As a result, efficient operation of the snowthrower may be maintained as the rotor wears, and the useful life of the rotor may be potentially extended. 
     Illustrative embodiments are described and reference has been made to possible variations of the same. These and other variations, combinations, and modifications will be apparent to those skilled in the art, and it should be understood that the claims are not limited to the illustrative embodiments set forth herein.