Abstract:
In a container and method for processing food, the container has a closed end, and open end and a tubular sidewall extending therebetween and together with the closed end defining an interior space of the container. The container is configured to accommodate a blade member within the interior space of the container. The container has a center and the sidewall has at least one rib projecting inward of the interior space of the container and extending heightwise along at least a portion of the sidewall. The rib is asymmetric in transverse cross-section. A blade member is also disclosed and is configured to have different planes in which the blade member moves upon rotation of the blade.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 61/782,879, filed on Mar. 14, 2013, which is incorporated in its entirety herein. 
     
    
     FIELD 
       [0002]    The field of the disclosure relates generally to food preparation appliances, and more particularly to food preparation appliances such as blenders and food processors that operate one or more blades within a container to process food disposed within the container. 
       BACKGROUND 
       [0003]    Food preparation appliances such as blenders and food processors are commonly use to process foods, such as by chopping, crushing, cutting, liquefying, blending, mixing, etc. Such appliances typically have a container in which the food is loaded for processing. The container has one or more blades disposed within the container and sits on a base that houses a drive motor that upon seating of the container on the base is drivingly connected to the one or more blades in the container. A lid is typically placed on the top of the container to close the container during operation of the appliance. 
         [0004]    In some blenders and food processors, the contents in the container tend to rotate about the inner volume of the container during processing. However, the contents are not always evenly mixed. Often times, for example, the contents nearest the blades may be liquefied, whereas contents located further from the blades remain intact (e.g., chunky). In order to improve the performance (i.e., improve the homogeneity of the mixed contents), at least some known containers include a series of ribs extending vertically along all or a portion of the inner sidewall of the container. These ribs may have varying sizes and shapes in cross-section, or contour as taken along the inner circumference of the container, but tend to have a symmetric incline and decline section along the circumferential contour of the inner sidewall of the container. The purpose of the ribs is to create turbulence in the contents of the container as they rotate within the container. 
         [0005]    When the contents rotate along the inner circumference of the container sidewall, they strike the ribs and will either travel upward (e.g., vertically) along the inclined side of the rib or travel circumferentially over the rib to its declined side. The contents that travel over the rib may enter a stagnant flow region on the declined side of the rib, and in some instances the contents can remain in the stagnant region for substantially the entire duration of operation of the appliance. As such, the contents in the stagnant zone are not well processed, and the final mixture is not homogeneous. Thus, the ribs may reduce the performance and the uniformity of the final mixture contents of the blender. 
         [0006]    The one or more blades of the appliance may also be shaped so as to impart both a rotational force and an axial force to the contents of the container during operation. For example, some blades are upwardly or downwardly angled to force the contents upward/downward as the blades strike the contents (e.g., the food), causing axial flow of the contents within the container. However, performance of the blades can vary with the speed at which the blades are rotated and the contents that are being mixed. In some instances, for example, excessive blade rotation speeds may induce cavitation within the contents being processed, or cause the contents to be forced upward and out of the top of the container. Cavitation within the contents may also cause non-uniformity in the final mixture and thus reduce the efficiency and usefulness of the appliance. 
         [0007]    As such, a need exists for a food preparation appliance that provides improved efficiency and uniformity of the processed contents. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0008]    In one aspect, a container for a food preparation appliance that includes a blade member rotatable relative to the container in a direction of rotation generally comprises a closed end and an open end. A tubular sidewall extends from the closed end to the open end and together with the closed end defines an interior space of the container. The container is configured to accommodate the blade member within the interior space of the container. The sidewall has a rim at the open end through which contents to be processed by the appliance are loaded into the interior space of the container, and the container has a center. The sidewall has a rib projecting inward of the interior space of the container and extending heightwise along at least a portion of the sidewall intermediate the open end and closed end of the container. The rib has, in the direction of rotation of the blade member, a peak defined as the shortest transverse dimension measured from the center of the container to the sidewall at a respective height along the portion of the sidewall having the rib, with the rib being asymmetric in transverse cross-section. 
         [0009]    In one aspect of a method for processing food in a food preparation appliance, the appliance has a container and a blade member rotatably driven within the container during operation of the appliance, and the container has a sidewall including an inner surface in part defining the interior space of the container in which food is processed. The method generally comprises loading food to be processed into the interior space of the container, and operating the blade member in a direction of rotation to generate a vortex flow of the food within the container in the direction of rotation of the blade member such that at least a portion of the flow of food flows circumferentially along the inner surface of the container sidewall. The portion of the flow of food flowing circumferentially along the inner surface of the container in the direction of rotation of the blade member is directed to impact a first rapidly inclining slope of the inner surface of the container sidewall and to then flow past a gradually declining slope of the container sidewall. 
         [0010]    In another aspect, a blade member for a food preparation appliance having a drive motor for operative connection with the blade member to drive rotation of the blade member about an axis of rotation of the blade member generally comprises a central planar portion extending substantially perpendicular to an axis of rotation of the blade member to lie in a first plane. The central planar portion has a first lengthwise end and a second lengthwise end opposite the first lengthwise end with the rotation axis of the blade member disposed therebetween. A first wing has a proximal end coupled to the first end of the central planar portion and a distal end disposed lengthwise outward of the proximal end of the first wing. A second wing has a proximal end coupled to the second lengthwise end of the central planar portion and a distal end disposed lengthwise outward of the proximal end of the second wing. At least a portion of one of the first wing and the second wing lies in a second plane different from the first plane of the central planar portion. An upturned wingtip extend generally upward from the distal end of one of the first wing and the second wing and a downturned wingtip extends generally downward from the distal end of the other one of the first wing and the second wing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a schematic side elevation of one embodiment of a food preparation appliance illustrated in the form of a blender. 
           [0012]      FIG. 2  is a side elevation of one embodiment of a container for use with the blender of  FIG. 1 , with a handle omitted from the container. 
           [0013]      FIG. 3  is a top plan view of the container of  FIG. 2 . 
           [0014]      FIG. 4  is a transverse cross-section taken midway along the height of the container of  FIG. 3 . 
           [0015]      FIG. 5  is a perspective view of one embodiment of a blade mount and blade member for use with the blender of  FIG. 1 . 
           [0016]      FIG. 6  is a perspective view of the blade member of  FIG. 5 . 
           [0017]      FIG. 7  is a top plan view of the blade member of  FIG. 5 . 
           [0018]      FIG. 8  is a front elevation thereof. 
           [0019]      FIGS. 9 and 10  are right and left side elevations, respectively, of the blade member of  FIG. 8 . 
           [0020]      FIG. 11  is a perspective view of one alternative embodiment of a blade member. 
           [0021]      FIG. 12  is a front elevation of the blade member of  FIG. 11 . 
           [0022]      FIG. 13  is a top plan of one alternative embodiment of a container for use with the blender of  FIG. 1 . 
           [0023]      FIG. 14  is a transverse cross-section taken midway along the height of the container of  FIG. 13 . 
           [0024]      FIG. 15  is a perspective of one alternative embodiment of a blade mount. 
           [0025]      FIG. 16  is a side elevation thereof. 
           [0026]      FIG. 17  is a side elevation of an alternative embodiment of a container with which the blade mount of  FIGS. 15 and 16  is used. 
       
    
    
       [0027]    Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Referring now to the drawings, and more particularly to  FIG. 1 , one embodiment of a food preparation appliance is indicated generally at  100  and is illustrated in the form of a blender. The blender  100  generally includes a base  102  housing a drive motor (not shown) therein, a container  104  releasably positionable on the base and having a blade mount  500  in operative connection with the drive motor and having a blade member  502  thereon, and a lid  105  for closing the container. As used herein, direction and/or orientation terms such as lower, upper, bottom and top refer to the upright orientation of the appliance  100  as illustrated in  FIG. 1 . The term transverse refers to a direction normal to the height of the container, e.g., horizontal in the illustrated embodiment of  FIG. 1 . While in the illustrated embodiment the appliance  100  is in the form of a blender, it is understood that the appliance may be in the form of a food processor or other suitable appliance in which a blade member operates within a container to process food or other contents in the container. 
         [0029]    With reference to  FIGS. 1-3 , the container  104  has a bottom  106  ( FIGS. 2 and 3 ), and a circumferential sidewall  108  extending up from the bottom  106  of the container so that the bottom and sidewall together define an interior space (broadly, a processing chamber)  114  of the container. The sidewall  108  terminates at an upper rim  112  to define an opening  110  at the top of the container  104  through which food or other contents to be processed are loaded into the interior space  114  of the container. As seen best in  FIG. 3 , the bottom  106  of the container  104  has a central opening  116  therethrough to permit operative connection between the blade mount  500  and the drive motor disposed in the base  102  of the blender  100  as discussed in further detail later herein. Although the central opening  116  is illustrated as being generally circular, it is understood that the opening may be any suitable shape that allows the blender  100  to function as described herein. 
         [0030]    In some embodiments, the container  104  may include a handle (not shown) for use in gripping and manipulating the container. The container  104  may also have a spout  118  ( FIG. 3 ) formed generally at its upper rim  112  to facilitate pouring out the contents of the container after processing. In the illustrated embodiment of  FIG. 2 , the sidewall  108  of the container  104  tapers outward in cross-sectional dimension from the bottom to the top of the sidewall, such that a cross-sectional dimension W 2  measured across the container at the rim  112  thereof is greater than a cross-sectional dimension W 1  measured across the container where the sidewall transitions to the bottom  106 . Such taper may improve blending of the contents therein, and also improves the ease of manufacturing the container  104 . As also seen in  FIGS. 3 and 4 , at the upper rim  112  of the container  104 , the container is generally circular (the spout  118  not withstanding), while the cross-section of the container is more triangular as the container sidewall  108  extends down toward the bottom  106  in accordance with the rib configurations described in further detail below. It is understood, however, that the container  104  may be of uniform cross-section along the height of the sidewall  108 , or may have a non-uniform cross-sectional dimension other than as illustrated in  FIGS. 2 and 3 , without departing from the scope of this invention. The container  104  may be constructed of any suitable material including, without limitation, plastic, glass, metal, metal alloys, composites and combinations thereof. 
         [0031]    With reference to  FIGS. 2 and 3 , the blade member  502  is rotatable relative to the container  104  in a rotational direction R as indicated by the direction arrow in  FIGS. 3 and 4 . In the illustrated embodiment, the container  104  has three rib sections  202 ,  204  and  206 , each extending vertically along a segment of the height of the container sidewall  108  generally from adjacent the bottom  106  of the container to a height less than the full height of the container such that the inner surface, or inner circumference of the sidewall is contoured along a vertical segment of the container. More particularly, with reference to a trace taken along the contoured inner circumference of the sidewall  108  in the direction of rotation R, each rib  202 ,  204 ,  206  has a respective peak  218  (for rib  202 ),  217  (for rib  204 ) and  212  (for rib  206 ). With reference to rib  202 , each rib includes a respective inflow segment  210  that widens in transverse dimension (e.g., in radius) along the rotational direction R leading into a respective base  214  of the rib  202 . The rib peak  218  (e.g., of rib  202 ) is defined by the point along the rib having the smallest transverse dimension (e.g., radius) measured from a center C of the container  104  to the rib peak  218 . The base  214  (e.g., of rib  202 ) is defined by the point along the rib having the largest transverse dimension measured from the center C to the rib base  214 . 
         [0032]    The rib  202  further includes a step  216  that decreases in transverse dimension (e.g., in radius) along the direction of rotation R from the rib base  214  to the rib peak  218  of the rib  202 . In the illustrated embodiment, the base  214  where the inflow segment  210  transitions to the step segment  216  is generally in the form of a fillet  220  (e.g., rounded) to create a smooth transition therebetween to thereby improve the flow characteristics of the container contents being processed. In other embodiments, however, the base  214  may be configured other than as a fillet, and may even define a straight corner, within the scope of this invention. The rib  202  also has an outflow segment  222  extending away from the peak  218  and along which the transverse dimension (e.g., radius) increases along the direction of rotation R. The outflow segment  222  transitions into the inflow segment  210  of the next rib  204  along the direction of rotation R. In this manner, for each rib (e.g., using rib  202  as an example), the inflow segment  210 , step  216 , peak  218  and outflow segment  222  together define a generally S-shaped contour, which creates a smooth transition between adjacent ribs  202 ,  204 ,  206 . 
         [0033]    The inflow segment  210  creates a gradual transversely (e.g., radially) outward slope along the direction of rotation R, whereas the step  216  has a relatively steep transversely inward slope to the peak  218  of the rib  202 . In some embodiments an angular distance a from the rib base  214  to the rib peak  218  is approximately one-third of an angular distance β between circumferentially adjacent rib peaks (e.g.,  217 ,  218 ). As one example, in the embodiment of  FIG. 3  the angular distance β between circumferentially adjacent rib peaks  217 ,  218  is about 120 degrees, such that the angular distance a from the rib base  214  to the rib peak  218  is less than about 40 degrees, and in the illustrated embodiment less than about 30 degrees. Additionally, at any given transverse cross-section of the container  104  along which the ribs  202 ,  204 ,  206  extend, a radial distance R P  from the center C of the container  104  to the peak  218  of the rib  202  is between about 60% to about 95% of a radial distance R B  from the center C of the container to the base  214  of the same rib  202 . 
         [0034]    With reference still to  FIGS. 2 and 3 , in the illustrated embodiment the container  104  further includes inclined ramp sections  300  (one associated with each rib  202 ,  204 ,  206 ) disposed axially (e.g. heightwise in the illustrated embodiment) between the bottom  106  of the container and the sidewall  108  thereof and circumferentially along the base  214 , step  216  and peak  218  of each respective rib (e.g., rib  202 ). Each ramp section  300  increases in height as it extends circumferentially in the direction of rotation R from the inflow segment  210  to the step  216  of the rib  202 . The height of the ramp section  300  also generally increases in height as it extends radially outward from the center of the container. As such, the height of the ramp section  300  is greater adjacent the base  214  and step  216  of the rib  202  than at the outflow segment  222  and inflow segment  210  of the rib. 
         [0035]    With reference now to  FIG. 5 , the blade mount  500  comprises a hub  504  and an externally threaded cylindrical column  506  depending from the hub such that the column extends down through the central opening  116  of the bottom  106  of the container  104  (see, e.g.,  FIG. 1 ) whereby the hub sealingly seats down against the inner surface of the bottom of the container. The illustrated hub includes a sealing gasket  508  to facilitate sealing engagement of the hub against the bottom  106  of the container  104 . A nut  510  or other suitable fastener is mounted on the threaded column below the bottom  106  of the container  104  for use in tightly securing the hub  504  on the bottom of the container. A drive shaft  606  extends through the  506  column for operative connection at one (i.e., upper) end to the blade member  502  and at an opposite (i.e., lower) end to a drive coupling  600  that operatively couples with the drive motor (not shown) in the base  102  of the blender  100 . The blade mount further includes an annular support plate  604  adjacent the upper end of the drive shaft  606 . 
         [0036]    With general reference to  FIGS. 6-10 , and in particular referring first to  FIG. 6 , the blade member  502  includes a central hub  700  having an opening  702  therein keyed to the cross-sectional configuration of the upper end of the drive shaft  606  of the blade mount  500  to thereby operatively connect the blade member  502  to the drive motor for driven rotation of the blade member relative to the container  104  upon operation of the drive motor. In some embodiments, the hub  700  and opening  702  of the blade member  502  may be configured relative to the drive shaft  606  such that the blade member  502  may only be installed on the blade mount  500  in a single orientation (i.e., such that the blade member cannot be installed upside down). The blade member  502  may be releasably or permanently connected to the blade mount  500  within the scope of this invention. The blade member  502  may be made of a metal, metal alloy, plastic, ceramic, composite or any other suitable materials and combinations thereof that allow the blade member  502  to function as described herein. In one suitable embodiment, for example, the blade member  502  is constructed of stainless steel. 
         [0037]    The blade member  502  has a planar portion  704  (including at least part of the blade member hub  700 ) extending substantially perpendicular to an axis of rotation A R  ( FIG. 8 ) of the blade member. A first wing  706  extends transversely outward from the planar portion  704  and has a proximal end  708  coupled to the planar portion  704  and a distal end  710  outward of the proximal end. A second wing  712  extends transversely outward from the planar portion  704  on a side of the hub  700  opposite the first wing  706 . The second wing  712  has a proximal end  714  coupled to the planar portion  704  and a distal end  716  outward of the proximal end  714  of the second wing  712 . An upturned wingtip  718  extends upward from the distal end  710  of the first wing  706  and a downturned wingtip  720  extends downward from the distal end  716  of the second wing  712 . The first wingtip  718  and the second wingtip  720 , according to one embodiment, are bent at a bend radius of between about 1 millimeter to about 5 millimeters. Each of the first wing  706  and the second wing  712  has a respective leading edge  722 ,  724  and a respective trailing edge  726 ,  728 . Each of the leading edges  722 ,  724  may be shaped to have a knife edge (i.e., an angled edge) to facilitate cutting of the contents to be processed in the container  104  when in use. In the illustrated embodiment, the planar portion  704  has opposite blunt, or squared, outer edges  730 ,  732 , although these edges may be partially or wholly sharpened to a knife edge to improve ease of manufacturing the blade member. 
         [0038]    Similarly, the first wingtip  718  and the second wingtip  720  may include an angled knife edge  734 ,  736  to further facilitate cutting or chopping of the contents of the container  104  in use. As seen best in  FIGS. 9 and 10 , the wingtips  718 ,  720  are generally rectangular in shape (e.g., in profile as viewed from the longitudinal ends). In other embodiments, however, one or both of the wingtips  718 ,  720  may be other than rectangular in profile and remain within the scope of this invention. For example, the leading edge  734 ,  736  of either one or both of the wingtips  718 ,  720  may be curved, e.g., rounded. The upper edges of the wingtips  718 ,  720  may also be rounded such that the leading edges  734 ,  736  and upper edges together form a single continuous knife edge that arcs from the leading edge  722 ,  724  of the wing  706 ,  712  to the trailing edge  726 ,  728 . 
         [0039]    As best illustrated in  FIGS. 8-10 , the planar portion  704 , the first wing  706 , and the second wing  712  each extend along a respective different plane such that the blade member  502  has a generally twisted appearance. The planar portion  704  is substantially perpendicular to the axis of rotation A R , which facilitates secure coupling of the blade member  502  to the blade mount  500 . More particularly, the planar portion  704  sits flat against the support plate  604  of the blade mount  500 . In the illustrated embodiment, the first wing  706  is twisted, such that the leading edge  722  is higher than the trailing edge  726 . The second wing  712  is also twisted such that its leading edge  724  is above its trailing edge  728 . In one example, each of the first wing  706  and the second wing  712  may be twisted to an angle α T  of between about 0.1 degrees to about 15 degrees with respect to the planar portion  704 . As such, when the blade member  502  is rotated in the first direction R ( FIG. 7 ), a propeller action is created, which forces contents in the container  104  that are contacted by the blade member in a downward direction toward the bottom  106  of the container. It should be understood that a lower twist angle reduces strain on the drive mechanism, but reduces the propeller action of the blade member  502 , while increased twist angles increase the strain on the drive mechanism but also increase the propeller action of the blade member in use. In other embodiments, one or both of the first and second wings  706 ,  712  may not be twisted and remain within the scope of this invention. 
         [0040]    Each of the first wing  706  and the second wing  712  has a radial length L 1 , L 2  ( FIG. 8 ) respectively measured from the axis of rotation A R  of the blade member  502  to a center of the respective wingtip  718 ,  720 . In the illustrated embodiment, L 2  is greater than L 1  such that the second wingtip  720  will pass closer to the upstanding sidewall  104  of the container than the first wingtip  718  during operation. However, in other embodiments, L 1  may be greater than L 2 , or L 1  and L 2  may be equal without departing from the scope of this invention. 
         [0041]    Referring to  FIGS. 6 and 8 , the first wingtip  718  is bent upward from the first wing  706  at an angle that is between 70 degrees and 110 degrees relative to the planar portion  704  of the blade member  502 . The second wingtip  720  is bent downward with respect to the second wing  728  at a downward angle less than 90 degrees relative to the planar portion  704 . However, the second wingtip  720  may be bent at any angle 90 degrees or less that allows the blade member  502  to function as described herein. In some embodiments, for example, the second wingtip  720  may be bent downward at an angle in the range of approximately 45 degrees to approximately 70 degrees with respect to the planar portion  704  of the blade member  502  to ease in the manufacturing of the blade member, or provide an alternate direction of movement of the contents being processed that is better suited for alternate container  104  geometries. As illustrated best in  FIGS. 9 and 10 , the wingtip  718  is configured such that the highest point of the leading edge  734  is the highest point of the blade member  502 . This ensures that as the blade member  502  rotates, the highest point of the leading edge  734  of the first wingtip  218  comes into contact first with larger objects or chunks (e.g., ice) that are sucked downward in the blender  100  toward the blade member. The leading edge  736  may be higher or lower than the trailing edge of the second wingtip without departing from the scope of this invention. 
         [0042]    With reference back to  FIG. 7 , the first (e.g., upturned) wingtip  718  of the illustrated embodiment is suitably angled relative to the generally straight leading edge  722  of the first wing  706  an angle θ T  in the range of about 50 degrees to 90 degrees. This further facilitates the leading edge  734  of the upturned first wingtip to come into contact with chunks (e.g., ice) in the middle (heightwise) region of the blender during use, thus minimizing the chances that large chunks will be left in the blender after processing. The second (downturned) wingtip  720  is suitably angled relative to the generally straight leading edge  724  of the second wing  712  an angle θ B  of less than 90 degrees, and more suitable less than 85 degrees. In this manner, as the blade rotates, the outer face of this wingtip  720  sweeps through the contents of the blender and pushes it radially outward, thus causing the material to get pushed into the sidewall  108  of the container for recirculation and chopping by the first wingtip  718 . This also helps circulation of the contents from the region surrounding the blade member  502 , up the sidewall  108  and back down the center of the vortex as described further below. 
         [0043]    It should be noted that the hub  504  of the blade mount  500  has a height (e.g., above the bottom  106  of the container  104 ) sufficient that the second wingtip  720  does not make contact with the bottom of the container when in use. In operation, as the blade member  502  is rotated in the first direction R ( FIG. 7 ), the first wingtip  718  may contact and break-apart large chunks of material in the container  104 , e.g., before the material is drawn downwardly toward the first wing  706  and the second wing  712  by the propeller action of the blade member  502 . The leading edges  722  and  724  then strike the material and further break apart the material. The material is then further propelled downward, where the second wingtip  720  then contacts the material. While in the illustrated embodiment the blade member  502  has two wings  706 ,  708 , it is understood that the blade member  502  may have a single wing, or it may have more than two wings, such as four wings, without departing from the scope of this invention. 
         [0044]    Operation of the blender  100  will now be described. The container  104 , with the blade member  502  and blade mount  500  assembled therewith, is placed on the blender base  102  as illustrated in  FIG. 1 . The drive coupling  600  of the blade mount  500  operatively connects to the drive motor (not shown) housed in the base  102  of the blender  100  such that the drive motor imparts a rotation to the drive coupling  600 , and thus the blade member  502 , upon operation of the drive motor. A user then loads the container  104  (with the lid  105  removed) with one or more materials (e.g., food or other contents to be processed). The lid  105  is then placed on the container  104  to close the interior space  114  of the container so as to inhibit spills or to otherwise inhibit the contents of the container from flowing out of the container during use. The blender  100  is then activated (e.g., by switch  107  illustrated in  FIG. 1 ) to operate the drive motor—thereby rotating the blade member  502  relative to the container  104 . 
         [0045]    As the blade member  502  rotates, the blade member contacts the contents of the container  100 , as discussed above. That is, the first wingtip  718  contacts the material, and the material is subsequently propelled downward and struck by the leading edges  722 ,  724  before it is again struck by the second wingtip  720 . Due to the rotation of the blade member  502 , the contents in the container  104  move in a downward direction as well as circularly in the direction of rotation R ( FIGS. 3 and 7 ) of the blade member. As such, a “vortex” may be generated in the contents above the blade member  502 . Thereupon, the propeller action of the blade member  502  continues to propel the contents downward toward the bottom  106  of the container  104  as well as radially outward toward the sidewall  108 . At least some of the contents flows outward and makes contact with the ramp sections  300  of the container  104 , which function to further propel the contents back up toward the top of the container. 
         [0046]    As the contents flow in the vortex (e.g., circular) motion within the container  104 , the contents being processed flow outward toward the sidewall  108  due to centrifugal force as well as by being pushed outward by the wingtips  718 ,  720 . With reference to  FIGS. 2 and 3 , the contents being processed thus flow generally circumferentially along the contour of the inner surface of the sidewall  108 . In this manner, the contents flow circumferentially along the inflow segment  210  of a particular rib (e.g., rib  202 ) to the base  214  and then the step  216 , wherein the contents are then directed transversely (e.g., radially) inward toward the center C of the container  104 . At this point, the contents meet another abrupt change in direction of the rib at the rib peak  218 , wherein the rib transitions to the outflow segment at which the transverse dimension begins to gradually increase into the inflow segment of the circumferentially next rib  204 . 
         [0047]    Without being bound to a particular theory, it is believed that the rapid change in direction caused by the contents flowing from the step  216  to the peak  218  creates turbulence in the vortex flow of the contents, and facilitates the contents moving in an upward direction along the sidewall  108  at or near the rib step  216  and peak  218 . The relatively gradual, transversely outward slope of the outflow segment  222  and inflow segment  210  provides a smooth transition from the peak of one rib to the base of the adjacent rib, which inhibits stagnant flow and ensures the material continues moving along the sidewall  108  in the direction of rotation of the blade member  502 . Further, the gradual increase in the transverse cross-sectional dimension of the sidewall  108  along its height from the bottom  106  to the upper rim  112  also facilitates the continuous flow of the contents. As the contents being processed flow to a higher level within the container  104 , the vortex motion of the contents caused by the propeller action of the blade member  502  again directs the material back downward toward the blade member wherein the flow path of the contents is generally repeated until the blender  100  is turned off. 
         [0048]      FIGS. 11 and 12  illustrate one embodiment of an alternative blade member  1502  having a hub  1700 , opening  1702  and planar portion  1704  similar to the embodiment of  FIGS. 6-10 . The blade member  1502  has a first wing  1706  and wingtip  1718  similar to the first wing  706  and wingtip  718  of the blade member  502  of  FIGS. 6-10 , with the exception that the first wing  1706  of this embodiment is not twisted. The blade member  1502  of this embodiment has a second wing  1720  that is also not twisted, and a downturned wingtip  1720 . The second wingtip  1720  has a leading edge  1736  with a rounded transition  1744  that continues to a tip  1742  at the trailing edge  1738  of the wingtip. The second wingtip  1720  of this alternate embodiment directs contents contacted by the second wingtip in a radially outward direction, similar to the second wingtip  720  of the blade member  502 . However, the second wingtip  1720  of this embodiment directs contents being processed in a more upward direction upon initial contact with the blade member and thus relies less on the configuration of the container  104  to circulate contents upward from the bottom of the container. 
         [0049]      FIGS. 13 and 14  illustrate one alternative embodiment of a container  1104  suitable for use with the blender  100  of  FIG. 1 . The container  1104  has a bottom  1106 , upper rim  1112 , ribs  1202 ,  1204 ,  1206  and ramps  1300  similar to the container  104  of  FIGS. 3 and 4 . In this embodiment, however, the ribs  1202 ,  1204 ,  1206  (with rib  1202  used as an example) include a step  1216  having a substantially steeper slope than the ribs  202 ,  204 ,  206  of the container  104  of  FIGS. 3 and 4 . As seen in  FIG. 13 , while the ribs generally fade into the sidewall  1108  toward the upper rim of the container  1104 , the upper rim  1112  of the container is relatively more triangular than circular as in the previous embodiment. 
         [0050]      FIGS. 15-17  illustrate one alternative embodiment of a blade mount  2500  and container  2104  in which the blade mount is capable of removable assembly with the container by inserting the blade mount and corresponding blade member  2502  thereon up through the opening (not shown) in the bottom of the container. The blade mount  2502  comprises a housing  2512  including an annular flange  2514  extending transversely outward from the housing generally at its lower end for seating against the bottom of the container  2104  (see, e.g.,  FIG. 17 ) about the central opening therein. As illustrated best in  FIG. 16 , a suitable drive coupling  2600  extends axially outward from the bottom of the housing  2512  for operative connection with the drive motor of the blender. The blade member  2502  is operatively connected to the drive coupling  2600  in the same manner as blade member  502  of the embodiment of  FIG. 5 . The blade member  2502  may be configured similar to any of the blade members  502 ,  1502  described previously herein. 
         [0051]    As illustrated in  FIG. 17 , the container  2104  has a downward extending collar  2120  defining the opening in the bottom of the container. The container  2104  may otherwise be configured in accordance with any of the containers  104 ,  1104  described previously herein. The opening at the collar  2120  is sized such that the blade member  2502  and blade mount housing  2512  are insertable upward through the opening until the annular flange  2514  of the blade mount seats up against the bottom of the collar  2120 . A suitable sealing gasket (not shown) may be used between the flange  2514  and the bottom of the collar  2120  to provide sealing engagement of the blade mount  2502  to the container  2504 . While not shown in the illustrate embodiment, the collar is externally threaded so that a suitable lock nut (not shown) can be used to removably retain the blade mount  2502  on the container  2504 . 
         [0052]    This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.