Abstract:
A mixing paddle for mixing dough and for cutting and mixing dense ingredients such as butter and shortening into dry ingredients such as flour has roughened cutting blades oriented at many angles. Some blades are attached between a central blade support shaft and a symmetrical rim. Blades near the apex of the rim rotate in concentric double cone paths. The blades may have roughed cutting edges to increase variety in fat chunk size and to improve mixing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional patent application Ser. No. 62/171,296, filed by the same inventor on Jun. 5, 2015. This application also claims the benefit of U.S. provisional patent application Ser. No. 62/345,373, filed by the same inventor on Jun. 3, 2016. 
    
    
     BACKGROUND 
     Traditionally, a baker mixes pie crust dough by pressing a pastry cutter against the bottom of a mixing bowl to cut butter and shortening into flour and other dry ingredients. The resulting mixture should have roughly pea-sized lumps of fat distributed evenly throughout the dry ingredients. This is usually achieved by repeatedly rotating a parallel-bladed pastry cutter to different positions, pressing the cutter into the ingredients, then briefly stirring the mix. Hand-mixing cold butter into flour with a pastry cutter can be time-consuming and exhausting. 
     Optimum cutter blade spacing is crucial to obtaining a proper mix. A pastry cutter with blades that are too far apart leaves oversized, poorly distributed lumps. Blades that are too close together tend to clog and create lumps that are too small to produce a flaky crust. Wire cutters mix poorly and often fail to conform to the contours of a mixing bowl. Mixing machines equipped with standard mixing paddles or dough hooks do little more than push ingredients around a mixing bowl. 
     Some people avoid the difficulties of making pie crust by purchasing pre-made crusts from stores. However, most people prefer fresh pie crust made to a favorite recipe, no matter how tedious and difficult it is to create. A mixing machine attachment that effectively cuts butter and shortening into dry ingredients would ease and simplify creation of homemade pie crust. 
     SUMMARY 
     An embodiment of invention is a food mixing machine attachment that allows a user to cut cold butter and shortening into a flour and dry ingredient mixture. Additionally, the attachment can be used to whip cream quickly and to efficiently mix thick batters, cookie doughs, and other hard-to-mix ingredients. The attachment may be compatible with any type of food mixing machine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a top right perspective view of an embodiment of the invention. 
         FIG. 2  shows a bottom right perspective view of the embodiment of  FIG. 1 . 
         FIG. 3  shows a bottom left perspective view of the embodiment of  FIG. 1 . 
         FIG. 4  shows a top plan view of the embodiment of  FIG. 1 . 
         FIG. 5  shows a bottom plan view of the embodiment of  FIG. 1 . 
         FIG. 6  shows a right elevation view of the embodiment of  FIG. 1 . 
         FIG. 7  shows a left elevation view of the embodiment of  FIG. 1 . 
         FIG. 8  shows a front elevation view of the embodiment of  FIG. 1 . 
         FIG. 9  shows a rear elevation view of the embodiment of  FIG. 1 . 
         FIG. 10  shows a front elevation view of the blades of the first enclosed region of  FIG. 8  isolated from surrounding structure and rotated 180 degrees around the long central axis of the central shaft. 
         FIG. 11  shows a top plan view of the blades of the first enclosed region of  FIG. 8  isolated from surrounding structure and rotated 45, 90 and 135 degrees around the long central axis of the central shaft. 
     
    
    
     DETAILED DESCRIPTION 
     In the Summary above and in the Detailed Description, and the claims below, and in the accompanying drawings, reference is made to particular features of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects and embodiments of the invention, and in the invention generally. 
     The term “comprises” and grammatical equivalents thereof are used herein to mean that other components, ingredients, steps, etc. are optionally present. For example, an article “comprising” (or “which comprises”) components A, B, and C can consist of (i.e., contain only) components A, B, and C, or can contain not only components A, B, and C but also one or more other components. 
     The term “at least” followed by a number is used herein to denote the start of a range beginning with that number (which may be a range having an upper limit or no upper limit, depending on the variable being defined). For example, “at least 1” means 1 or more than 1. The term “at most” followed by a number is used herein to denote the end of a range ending with that number (which may be a range having 1 or 0 as its lower limit, or a range having no lower limit, depending upon the variable being defined). For example, “at most 4” means 4 or less than 4, and “at most 40%” means 40% or less than 40%. When, in this specification, a range is given as “(a first number) to (a second number)” or “(a first number) (a second number),” this means a range whose lower limit is the first number and whose upper limit is the second number. F or example, 25 to 100 mm means a range whose lower limit is 25 mm, and whose upper limit is 100 mm. 
       FIG. 1  shows a top right front perspective view of a mixing paddle  100  that is especially effective for cutting and mixing dense ingredients such as cold butter and shortening into dry and wet ingredients to form pastry dough, cookie dough, thick batter and other non-uniform mixtures. The mixing paddle  100  of  FIG. 1  has a central shaft  102  with a cylindrical base member  104  terminated at a first base member end  105  by an attachment member  106 . The base members  104  and attachment members  106  shown in  FIGS. 1, 8 and 9  represent a generalized form that may in alternate embodiments include holes, splines, flanges and other structures known in the art to be suitable for attaching the mixing paddle  100  to the beater shaft of a stand mixer, or to a hand mixer or other mixing device.  FIGS. 2 through 7  show a commonly-used attachment member. Once attached to a mixing device the mixing paddle  100  is rotated by the mixing device through ingredients in a mixing bowl in a manner well-known in the art. 
     In the embodiment of  FIG. 1  the central shaft  102  forms a blade support member  108  by tapering along its length from a second base member end  107  to a blade support member end  112 . As the central shaft  102  tapers from the second base member end  107  to the blade support member end  112  the cross-sectional dimensions of the blade support member  108  diminish more rapidly on a first transverse axis than on a second transverse axis that is normal to the first transverse axis, resulting in a blade support member  108  with a cross-section that changes from circular near the second base member end  107  to elliptical or stadium-shaped at the blade support member end  112 . In this embodiment the longest cross-section dimension of the blade support member end  112  parallels the second transverse axis. 
     A scutiform rim  110  partially or completely surrounds the blade support member  108 . In alternate embodiments the rim  110  may be a Reuleaux triangle or other shape that at least partially conforms to the inner contours of a mixing bowl. In many embodiments a first straight rim member  114  and a second straight rim member  115  radiate from opposite sides of the base member  104  and are normal to the base member  104 . The first straight rim member  114  is symmetrical to the second straight rim member  115 . 
     A first curved rim member  116  arcs from a distal end  120  of the first straight rim member  114  to an apex  122  at which first straight rim member  114  joins a second curved rim member  118 . The second curved rim member  118  arcs from a distal end  121  of the second straight rim member  115  to the apex  122 . The first curved rim member  116  is symmetrical to the second curved rim member  118 . The apex  122  is aligned with the center of central shaft  102 . 
     In the embodiment of  FIG. 1  the straight and curved rim members  114 ,  115 ,  116 ,  118  are thin, flat and wide. The wide dimension of the apex  122  parallels the second transverse axis of the blade support member end  112 . Other embodiments of the invention may employ rim members with circular, triangular or other cross-sectional shapes and proportions. The straight and curved rim members  114 ,  115 ,  116 ,  118  are positioned in reflective symmetry with respect to the blade support member  108  so that the curved rim members  116 ,  118  travel the same path when the mixing paddle  100  rotates about the long central axis  816  of the central shaft  102 . 
       FIG. 8  shows a front elevation view of the embodiment of  FIG. 1 . In this embodiment the blade support member end  112  is connected to the second curved rim member  118  by a first rim support member  802 . While this embodiment also has second  806  and third  804  rim support members, other embodiments may have more or fewer rim support members that connect the blade support member  108  to the rim  110  to maintain the position of the rim  110  with respect to the central shaft  102 . In the embodiment of  FIG. 8  the first rim support member  802  joins the second curved rim member  118  at an angle between 80 and 110 degrees and is oriented at a 40 degree angle with respect to the long central axis  816 . 
     A plurality of thin blades  824  also span the area between and are connected to the blade support member  108  and the curved rim members  116 ,  118 . In a preferred embodiment each blade is a thin, straight rectangular metal strip with one long edge having a roughened cutting edge. The roughened edge creates fat chunks of varied sizes and with irregular surfaces. In the embodiment of  FIG. 8  the blades are spaced between 6 millimeters and 13 millimeters apart to cut fat into small enough chunks to ensure desired fat distribution while minimizing clogs that may occur between tightly-spaced blades. The rim  110  and the central shaft  102  would have reflective symmetry with respect to a bisecting plane containing the long central axis and bisecting both the rim  110  and the central shaft  102  into equal halves. The wide dimension of each rectangular blade is the minimum distance between the blade&#39;s longest edges. In this embodiment all blades are oriented with their wide dimensions normal to the bisecting plane of the mixing paddle  100 . 
     As the mixing paddle  100  rotates through ingredients the rough-edged blades  824  tend to drag fat chunks along rather than slicing through them cleanly, thereby promoting better mixing. Fat chunks of different sizes that are well-distributed in pastry dough produce flakiness in a baked pie crust. 
     In the embodiment of  FIG. 8  the blades  824  are grouped into four enclosed regions defined by the rim members, rim support members and the blade support member. In alternate embodiments blades may be partially enclosed by rim members and/or may serve as support members. In the embodiment of  FIG. 8 , the fourth enclosed region  808  is bordered by the blade support member  108 , the second rim support member  806 , a portion of the first curved rim member  116  and the first straight rim member  114 . The second enclosed region  810  is bordered by the blade support member  108 , the first rim support member  802 , a portion of the second curved rim member  118 , and the third rim support member  804 . The third enclosed region  812  is bordered by the blade support member  108 , the third rim support member  804 , a portion of the second curved rim member  118  and the second straight rim member  115 . The first enclosed region  814  is bordered by the first rim support member  802 , the blade support member end  112 , the second rim support member  806 , a portion of the first curved rim member  116 , the apex  122  and a portion of the second curved rim member  118 . 
     The blades  824  in the second  810 , third  812  and fourth  808  enclosed regions are all at proximal ends attached to or integral with the blade support member  108  and are oriented in an approximately radial manner with respect to the blade support member  108 . The blades  824  in the fourth enclosed region  808  are all at distal ends attached to or integral with the first curved rim member  116 , with the blades  824  intersecting the first curved rim member  116  at angles between 80 and 110 degrees. The blades  824  in the second and third enclosed regions  810 ,  812  are all at distal ends attached to or integral with the second curved rim member  118 , with the blades  824  intersecting the second curved rim member  118  at angles between 80 and 110 degrees. 
     The blades in the first enclosed region  814  span the distance between the first curved rim member  116  and the first rim support member  802 . The blades in the first enclosed region  814  are at a distal end attached to or integral with the first curved rim member  116  and at a proximal end attached to or integral with the first rim support member  802 . The blades in the first enclosed region  814  are oriented at angles between 85 and 95 degrees with respect to the first rim support member  802 , angles between 80 and 110 degrees with respect to the first curved rim member  116 , and angles between 50 and 60 degrees with respect to the long central axis  816 . In alternate embodiments the first rim support member  802  may be oriented at angles greater or smaller than 40 degrees with respect to the long central axis  816 . 
     In this embodiment roughened edges on blades within the second  810  and third  812  enclosed regions are on an opposite of the bisecting plane with respect to roughened edges on the blades within the fourth enclosed region  808 . Each blade with the first enclosed region  814  may have either or both edges roughened. 
     When the mixing paddle  100  is rotated about the long axis  816  of the central shaft  102 , the blades  824  in the first enclosed region  814  and at least one of blades  824  in the second enclosed region  810  pass through ingredients in a mixing bowl. Since the blades  824  in the second enclosed region  810  and the first rim support member  802  are oriented at angles close to 90 degrees with respect to the blades  824  in the first enclosed region  814 , fat chunks and dry ingredients are rapidly cut at different angles. 
     Additionally, the long axis  816  of the central shaft  102  passes through the blades in the first enclosed region  814 . When the mixing paddle  100  is rotated about the long axis  816  of the central shaft  102  the blades in the first enclosed region  814  travel concentric double cone paths, with the joined apices of each pair of conical paths falling between the ends of an individual blade. Portions of each blade  824  in the first enclosed region  814  form different parts of a double cone path while moving in opposite directions. Each blade  824  forms a separate double cone path. Each double cone path is offset from the others. The complex circulation caused by the combined motions of the blades in the first enclosed region  814  results in both rapid cutting and efficient mixing of non-uniform mixtures. 
       FIGS. 10 and 11  show simplified views of the rotational motion of the blades  824  of the first enclosed region  814  of the embodiment of  FIG. 8 .  FIG. 10  shows the blades  824  of the first enclosed region  814  of the embodiment of  FIG. 8  isolated from and without the first rim support member  802 , the second rim support member  806 , the first curved rim member  116  and the second curved rim member  118 . The isolated blades  824  of  FIG. 10  are shown in solid lines in a first position  1002 , then rotated 180 degrees along a circular path  1003  to a second position  1004 . Each end of each blade  824  travels a separate, concentric circular path around the long central axis  816 . The circumference of each path is at a minimum where a blade  824  intersects  1005  the long central axis  816 .  FIG. 11  shows a top plan view of isolated blade  824  rotational paths, with blades  824  rotated 45, 90 and 135 degrees around the long central axis  816  of the central shaft  102 . Although the rotational paths shown in  FIG. 10  are tilted slightly with respect to the long central axis  816  to better show their circular nature, when the mixing paddle  100  is in use the long central axis  816  is orthogonal to the circles bounded by the rotational paths. 
     Embodiments of the invention may be manufactured from materials such as but not limited to stainless steel, cast iron, aluminum, ceramics and plastics by casting, machining, welding, 3-D printing and other techniques well-known in the art. The mixing paddle may then be used with stand mixers, hand mixers and other mixing apparatus known in the art. 
     In an alternate embodiment of the invention a scraper may be attached to one of more rim members to remove and collect ingredients from inner sides of a mixing bowl when the mixing paddle rotates. The scraper can be made of materials such as but not limited to metal, plastic and rubber. The scraper can be thinner or thicker than the rim members with the same shape as the curved rim members. 
     The principles, embodiments, and modes of operation of the present invention have been set forth in the foregoing specification. The embodiments disclosed herein should be interpreted as illustrating the present invention and not as restricting it. The foregoing disclosure is not intended to limit the range of equivalent structure available to a person of ordinary skill in the art in any way, but rather to expand the range of equivalent structures in ways not previously contemplated. Numerous variations and changes can be made to the foregoing illustrative embodiments without departing from the scope and spirit of the present invention.