Abstract:
A mill for grinding a spice or grain material has a grinding mechanism including: a lever mounted for pivotal movement about a lever axis, a grinder bit mounted for rotational movement about a grinder bit rotational axis, the grinder bit rotational axis being at least approximately parallel to the lever axis, and a linkage coupled to the grinder bit and coupled to the lever to transfer pivotal movement from the lever to the grinding bit. The grinder bit may be cylindrical and include a gradated set of teeth. A cam pivots an engagement surface to adjust a spacing between the engagement surface and the grinding bit to select a size of resulting particles.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention is generally related to grinding mechanisms, and more particularly to grinders or mills for grinding materials, such as spices and grain.  
         [0003]     2. Description of the Related Art  
         [0004]     Mills for grinding materials such as spices and grains are common household items. For example, pepper mills are ubiquitous in households and restaurants. Such mills generally include a housing or body which presents an attractive outward appearance, and which forms a chamber or reservoir for holding a material (e.g., peppercorns) to be ground. The body also typically encloses a grinding mechanism in fluid communication with the chamber, the grinding mechanism grinding the material and dispensing the ground material through an opening or exit in the bottom of the body. The grinding mechanism typically includes an actuator (e.g., crank arm, operating lever), a grinding bit, an engagement surface for cooperating with the grinding bit to grind the material therebetween, and a transmission drivingly coupling the actuator to the grinding bit. Often the body will form a second chamber, separate from the first chamber, for holding a material that does not requiring grinding (e.g., salt).  
         [0005]     Most mills are hand operated and may be used by chefs or cooks in the preparation of food, or by servers and/or diners at dining tables. Many mills have a crank arm which is turned continuously and unidirectionally (e.g., clockwise or counterclockwise) with one hand of the user, while the other hand holds the mill in a generally vertical direction such that the ground material drops out of the bottom. Other mills have an operating lever which is reciprocatingly operated (i.e., bi-directionally) with the fingers or thumb of the hand holding the mill.  
         [0006]     Typically, the grinding mechanisms fall into two categories, rotary mechanisms and linear mechanisms. Many rotary mechanisms are driven by turning a crank arm directly connected to a drive shaft of the grinding mechanism, which in turn is directly connected to the grinding bit. The crank arm, drive shaft and grinding bit each rotate about respective axes or rotation, the axes being parallel to each other, or even collinear. A number of rotary mechanisms are driven by reciprocating movement of an operating lever. Such rotary mechanisms include a grinding bit axially mounted on a drive shaft, and transmission means in the form of gears for translating the reciprocating motion of the operating lever into rotation of the drive shaft for driving the grinding bit. Again, the axes of rotation of the drive shaft and grinding bits are parallel or even collinear. Linear grinding mechanisms rely on linear movement of the grinding bit to grind the material. Typically, linear mechanisms employ the axial translation of a transmission element, such as a rack, to produce the linear translation of the grinding bit.  
         [0007]     Most grinders also include mechanisms for adjusting the space between the grinding bit and the engagement surface to allow the user to select a desired grain size. In rotary mechanisms, the grinding bits are typically conical and having a uniform set of teeth around the periphery of the cone or truncated cone. The space between the engagement surface and the grinding bit may be adjusted by translating the conical grinding bit along its longitudinal axis with respect to the engagement surface. In linear mechanisms, the grinding bit typically takes the form of a straight or beveled surface having a set of uniform teeth. The space between the engagement surface and the grinding bit is adjusted by translating the grinding bit either toward or away from the engagement surface.  
         [0008]     It is desirable to reduce the cost and complexity of mills. It is also desirable to produce mills that are sturdy and easy to operate. Further, it is desirable to provide a mill that efficiently and uniformly grinds material to any selected size.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     In one aspect, a mill for grinding a spice or grain material includes a body, a grinder bit at least partially received in the body and mounted for pivotal movement about a grinder bit rotational axis, a linkage at least partially received in the body and mounted for translation in a linkage plane, the linkage plane being non-parallel to the grinder bit rotational axis, the linkage coupled to the grinder bit at a point on the grinder bit spaced from the grinder bit rotational axis, and an engagement surface opposed to the grinder bit and spaced therefrom to cooperatingly receive the material to be ground therebetween.  
         [0010]     In another aspect, a grinding mechanism for a grinder includes a lever mounted for pivotal movement about a lever axis, a grinder bit having a grinding surface, the grinder bit mounted for rotational movement about a grinder bit rotational axis, the grinder bit rotational axis being at least approximately parallel to the lever axis, and a linkage coupled to the grinder bit and coupled to the lever to transfer pivotal movement from the lever to the grinding bit.  
         [0011]     In a yet another aspect, a grinding mechanism includes a grinding bit mounted for rotation, an engagement member having an engagement surface opposed to the grinding bit, the engagement member mounted for pivotal movement about an adjustment axis with respect to the grinding bit to selectively adjust a space between the grinding bit and the engagement surface of the engagement member to receive material to be ground therebetween, and a cam mounted for rotation, the cam having a first cam surface engaging a portion of the engagement member.  
         [0012]     In a further aspect, a grinding bit for a spice grinder includes a cylindrical body having a peripheral edge, and a number of grinding protuberances extending along the peripheral edge between a first angular position and a second angular position, the grinding protuberances being of at least two different sizes, the grinding protuberances gradating in size between the first and the second angular positions. The grinding protuberances may, for example, take the form of teeth or knurls.  
         [0013]     In yet a further aspect, a spice mill includes a lever mounted for pivotal movement about a lever axis, rotatable means for grinding mounted for rotation about a grinder rotation axis, the grinder axis parallel to the lever axis, and axial linkage means for coupling pivotal movement of the lever to the rotatable grinding means.  
         [0014]     In an even further aspect, a method of operating a grinding mechanism includes pivoting a lever about a lever axis and rotating a grinder bit about a grinder bit rotational axis at least approximately parallel to the lever axis in response to the pivoting of the lever about the lever axis.  
         [0015]     In yet an even further aspect, a method of operating a grinding mechanism includes pivoting a cam about a cam axis, and pivoting an engagement surface about an adjustment axis with respect to a grinder bit where the adjustment axis is perpendicular to the cam axis to adjust a spacing between the engagement surface and the grinder bit. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0016]     In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings.  
         [0017]      FIG. 1  is a side, top isometric view of a mill for grinding material such as spices or grain.  
         [0018]      FIG. 2  is a cross-sectional view of the mill of  FIG. 1 , taken through the longitudinal axis of a body of the mill, showing a grinding mechanism including a lever, linkage, grinding bit, engagement member having an engagement surface, and cam, and also showing material to be ground within a chamber formed by the body and ground material exiting the mill.  
         [0019]      FIG. 3  is a side elevational view of an exemplary grinding bit including a set of grinding protuberances in the form of a gradated set of teeth.  
         [0020]      FIG. 4  is an isometric view of an exemplary grinding bit including a set of grinding protuberances in the form of a knurled gradated surface.  
         [0021]      FIG. 5  is a side elevational view of an exemplary grinding bit including a set of grinding protuberances in the form of a set of uniformly sized teeth.  
         [0022]      FIG. 6  is a side elevational view of a first adjustment mechanism including a set of cams having opposed cam surfaces, rotated to pivotally position the engagement member in a first position.  
         [0023]      FIG. 7  is a side elevational view of the first adjustment mechanism of  FIG. 6  illustrating the cams rotated 180 degrees from that of  FIG. 6 , to pivotally position the engagement member in a second position.  
         [0024]      FIG. 8  is a side elevational view of a second adjustment mechanism including a cam rotated to pivotally position the engagement member in a first position.  
         [0025]      FIG. 9  is a top plan view of the second adjustment mechanism, the cam rotated to pivotally position the engagement member in the first position of  FIG. 8 .  
         [0026]      FIG. 10  is a side elevational view of the second adjustment mechanism of  FIG. 8 , illustrating the cam rotated from that of  FIG. 8 , to pivotally position the engagement member in a second position.  
         [0027]      FIG. 11  is a top plan view of the second adjustment mechanism, the cam rotated to pivotally position the engagement member in the second position of  FIG. 10 .  
         [0028]      FIG. 12  is a side elevational view of the second adjustment mechanism of  FIG. 8 , illustrating the cam further rotated from that of  FIG. 10 , to pivotally position the engagement member in a third position.  
         [0029]      FIG. 13  is a top plan view of the second adjustment mechanism, the cam rotated to pivotally position the engagement member in the third position of  FIG. 13 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]     In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the invention. However, one skilled in the art will understand that the invention may be practiced without these details. In other instances, well-known structures associated with mills and grinding mechanisms have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments of the invention.  
         [0031]     Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limiting to.” 
         [0032]     The headings provided herein are for convenience only and do not interpret the scope of meaning of the claimed invention.  
         [0033]      FIG. 1  shows a grinder or mill  10  for grinding a material such as spices (e.g., pepper, salt) or grains. The mill  10  includes a body  12  and a lever  14  at least a portion of which is accessible from outside the body  12 . The body  12  may take the form of a body of revolution, although any other aesthetically pleasing shape may be employed.  
         [0034]      FIG. 2  shows a grinding mechanism  16  of the mill  10 . The grinding mechanism  16  includes the lever  14 , a grinding bit  18 , and a linkage  20  drivingly coupling the lever  14  to the grinding bit  18 . The lever  14  includes a first end  22  and a second end  24 , and is mounted proximate the second end  24  for reciprocating pivotal movement illustrated by double-headed arrow  26  about a lever axis  28 . The lever  14  has a neutral position, illustrated in solid line in  FIG. 2 . In one embodiment, the lever  14  can be reciprocatingly moved between the neutral position and one of a pair of fully displaced positions  29 ,  31 , illustrated in broken line in  FIG. 2 . In another embodiment, the lever  14  can be reciprocatingly moved between the pair of fully displaced positions. The lever  14  can be operated using one hand, while the other hand holds the body  12  of the mill  10 .  
         [0035]     The grinding bit  18  may take the form of a wheel or cylinder mounted for rotation, illustrated by double-headed arrow  30 , about a grinding bit rotation axis  32 . The lever axis  28  and grinding bit rotation axis  32  are parallel within acceptable manufacturing tolerances. The illustrated grinding bit is cylindrical, in contrast to the conical grinding bits typically employed in rotary grind mechanisms, and may take the form of a right cylinder. The grinding bit  18  may include an edge or periphery  34 . The grinding bit  18  may also include one or more grinding protuberances, discussed in detail below with reference to  FIGS. 3-5 .  
         [0036]     The grinding bit  18  cooperates with an engagement surface  38  of an engagement member  40  such as a shear block, the engagement surface  38  being opposed to, and spaced from, the grinding bit  18  to receive and grind a material to be ground  15  therebetween. In particular, the illustrated engagement surface  38  is arcuate proximate at least one end  43  thereof, the arcuate portion having a radius of curvature complementing a radius of curvature of the periphery  34  of the grinding bit  18 . In the alternative, the engagement surface  38  of the grinding bit  18  can be formed without the arcuate portion, without deviating from of the invention. The material to be ground  15  may be stored in a chamber  13  formed by the body  12  of the mill  10 . The flow of material to be ground  15  from the chamber  13  to the grinding bit  18  is illustrated by arrow  17 . The ground material  45  exits the mill  10  via an exit aperture  46 , typically in the bottom of the body  12 .  
         [0037]     The space between the grinding bit  18  and the engagement surface  38  is adjustable by way of a cam mechanism  42 , which pivots the engagement member  40  about and adjustment axis  41 , as illustrated and discussed in more detail below with reference to  FIGS. 6-11 .  
         [0038]     The linkage  20  has a first end  48  and a second end  50 . The first end  48  of the linkage  20  is pivotally coupled to the second end  24  of lever  14 , spaced from the lever axis  28  to gain mechanical advantage. The second end  50  of the linkage  20  is pivotally coupled to the grinding bit  18 , spaced from the grinding bit rotation axis  32 . As the lever  14  is moved from the neutral position to the fully displaced positions, the linkage  20  translates in a linkage plane  51  illustrated by broken line box. The linkage plane  51  is perpendicular to the lever axis  28  and the grinding bit rotation axis  32 . The linkage  20  may also rotate slightly, within the linkage plane  51 . In contrast to typical rotary grinding mechanisms, this rotation is about an axis that is perpendicular to a longitudinal axis illustrated by double-headed arrow  52  of the linkage  20 .  
         [0039]     The mill  10  may include an optional biasing member, such as a spring or other resilient member. For example, a compression spring  54  is coupled between the body  12  and the linkage  20  to bias the lever  14  toward the neutral position from the displaced positions. In alternative embodiments, the biasing member may be coupled between the body  12  and the lever  14  or grinding bit  18 . In further alternatives, the biasing member may be coupled between various elements of the grinding mechanism  16 . For example, the biasing member may take the form of a coil or spiral spring coupled to the grinding bit. Alternatively, the mill  10  may omit the biasing member, relying on the user to return the lever  14  to the neutral position from one or both displaced positions.  
         [0040]      FIG. 3  shows one embodiment of the grinding bit, having a set of grinding protuberances in the form of a set of teeth  60  on the periphery  34  of the grinding bit  18 . The teeth  60  may be gradated between a first angular position  62  and a second angular position  64 , as illustrated in  FIG. 3 . Thus, the size of the teeth  60  becomes increasingly smaller as the periphery  34  is transversed between the first angular position  62  and the second angular position  64 . In one embodiment, each tooth  60  is successively smaller than a previous tooth as the periphery is transversed from the first to the second angular positions  62 ,  64 , respectively. In another embodiment, the teeth  60  are grouped in sections, each section having teeth  60  of a uniform size, with the section having the largest teeth  60  positioned proximate the first radial position  62  and the section having the smallest teeth  60  positioned proximate the radial position  64 . Thus, there is a gradation in size of the teeth  60  between the various sections, but uniformity of size of the teeth  60  within any given section.  
         [0041]     The larger teeth  60  may be positioned toward a top of the mill  10 , where the material to be ground  15  first enters the space between the grinding bit  18  and the engagement surface  38 . The smaller teeth  60  may be positioned relatively toward the bottom of the mill  10 , close to the exit aperture  46 , where the ground material  45  exits the body  12  of the mill  10 . The grinding bit  18  may employ other arrangements of teeth or grinding protuberances, although this arrangement ensures that the material  15  is successively acted upon by successively finer teeth as the particle size of the material becomes successively smaller. One skilled in the art will also recognize that the grinding protuberances may extend completely about the periphery  34  of the grinding bit  18 , for example, where such would lower the manufacturing cost of the grinding bit  18 .  
         [0042]      FIG. 4  shows another embodiment of the grinding bit  18 , having a set of grinding protuberances in the form of a knurled surface  65  on the periphery  34  of the grinding bit  18 . As illustrated, the knurled surface  65  may be gradated between the first and the second angular positions  62 ,  64 , respectively. Alternatively, the knurled surface may be uniform between the angular positions  62 ,  64 . The grinding bit  18  may employ other textured surfaces as the grinding protuberances, or may even omit texture in some embodiments.  
         [0043]      FIG. 5  shows yet another embodiment of the grinding bit  18 , having a set of grinding protuberances in the form of a set of uniformly sized teeth  67  between the first and the second angular positions  62 ,  64 , respectively, on the periphery  34  of the grinding bit  18 .  
         [0044]      FIGS. 6 and 7  show a first adjustment mechanism, employing the cam  42  to pivot the engagement member  40  about the adjustment axis  41  to adjust the space between the engagement surface  38  and the grinding bit  18 . The cam  42  is mounted for rotation about a cam axis  44 , and includes an operating mechanism such as a lever or tab  72  accessible from outside the body  12  of the mill  10 . The cam  42  includes at least one cam surface  74  for engaging a portion of the engagement member  40  to rotate the engagement member  40  between a first position illustrated in  FIG. 6  and a second position illustrated in  FIG. 7 . Thus, the engagement member  40  pivots between an angle α and an angle β. In the illustrated embodiment, the cam  42  includes a second cam surface  76  opposed to the first cam surface  74 . The cam surfaces  74 ,  76  may be formed as beveled discs  78 ,  80  on a shaft  82 . The cam surfaces  74 ,  76  can be arranged to form a necked region  84  therebetween to further urge the engagement member  40  into the desired position.  
         [0045]      FIGS. 8-13  show a second adjustment mechanism, employing a cam  42  to pivot the engagement member  40  about the adjustment axis  41  to adjust the space between the engagement surface  38  and the grinding bit  18 . The cam  42  is mounted for rotation about an off-centered cam axis  44 , and selectively engages portions of the engagement member  40 . For example, in the illustrated embodiment the cam  42  engages portions of a cam slot  86  formed in or through the engagement member  40 . The second adjustment mechanism includes an operating mechanism such as a lever or tab  72  coupled to turn the cam  42  and accessible from outside the body  12  of the mill  10 . The cam  42  may have a variety of cross-sections, including but not limited to non-circular cross-sections such as an ellipse. As illustrated in  FIGS. 9, 11  and  13 , the cross-section of the cam  42  may further include a number of flatten portions  85  that serve as detents to create a number of discrete adjustments to the spacing between the engagement surface  38  and the grinding bit  18 .  
         [0046]     In  FIG. 9  the tab  72  is in a first angular position about the cam axis  44  such that the cam  42  engages a portion  87  of the cam slot  86 . As shown in  FIG. 8 , the engagement permits the engagement member  40  to assume a first angular position about the adjustment axis  41 , producing a first spacing between the engagement surface  38  and the grinding bit  18 .  
         [0047]     In  FIG. 11  the tab  72  is rotated to a second angular position about the cam axis  44  from that shown in  FIG. 9 , such that the cam  42  engages a portion  87  of the cam slot  86 . As shown in  FIG. 10 , the engagement permits the engagement member  40  to assume a second angular position about the adjustment axis  41 , producing a second spacing between the engagement surface  38  and the grinding bit  18 . The second spacing is greater than the first spacing shown in  FIG. 8 . As best illustrated in  FIG. 10 , the cam slot  86  may be tapered or include a filet or rounded edges to provide sufficient clearance for the engagement ember to rotate about the adjustment axis.  
         [0048]     In  FIG. 13  the tab  72  is further rotated to a third angular position about the cam axis  44  from that shown in  FIG. 11 , such that the cam  42  engages a portion  87  of the cam slot  86 . As shown in  FIG. 12 , the engagement permits the engagement member  40  to assume a third angular position about the adjustment axis  41 , producing a third spacing between the engagement surface  38  and the grinding bit  18 . The third spacing is greater than the second spacing shown in  FIG. 10 .  
         [0049]     As will be recognized by those skilled in the art, where the cross-section of the cam  42  includes flatten portions, a discrete number of adjustments will be available. Where the cross-section of the cam  42  is a smooth curve, such as an ellipse, the number of available adjustments between some maximum and minimum spacing is unlimited.  
         [0050]     Although specific embodiments of examples for the grinder or mill are described herein for illustrative purposes, various equivalent modifications can be made without departing from the spirit and scope of the invention, as will be recognized by those skilled in the relevant art. Teachings provided herein of the invention can be applied to other grinders or mills, not necessarily the exemplary mill generally described above.  
         [0051]     These and other changes can be made to the invention in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims, but should be construed to include all grinders or mills that operate in accordance with the claims. Accordingly, the invention is not limited by the disclosure, but instead its scope is to be determined entirely by the following claims.