Abstract:
A handheld apparatus for mixing food product comprising a manual input and a drive structure comprising a drive input, wherein the manual input is operatively connected to the drive input to actuate the drive means, the drive means further comprising first and second drive outputs operatively coupled to the drive input and being arranged to simultaneously rotate the first drive output in a first direction and rotate the second drive output in a second direction and rotate both drive outputs in the second direction about the central axis of the apparatus, such that the number of revolutions completed by the first drive output is less than the number of revolutions completed by the second drive output each time the drive outputs complete a revolution about the central axis.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119(a)-(d) to European patent application number 16177613.3, filed on Jul. 1, 2016, which is hereby incorporated by reference herein in its entirety. 
       TECHNICAL FIELD 
       [0002]    This disclosure generally relates to an apparatus for mixing food products and/or liquids. In particular, this disclosure relates to a manually operated, handheld mixing apparatus. 
       BACKGROUND 
       [0003]    Mixers are widely used as convenient means for mixing food products and/or liquids such as eggs, flour, milk, butter and the like. Many different types of mixers are known including handheld mechanical mixers, such as an eggbeater, handheld electric mixers and stand mixers. Mechanical mixers are manually operated to rotate two beaters to provide a mixing action. However, such a mixing action is not always effective, particularly when trying to mix wet and dry food products. Handheld electric mixers are capable of rotating the beaters at higher speeds, albeit with the same mixing action as mechanical mixers. However, the inclusion of a motor means that they are heavier than mechanical mixers, which can make them cumbersome to use. Moreover, handheld electric mixers, of course, need to be connected to a power supply, which makes them less convenient when compared to mechanical mixers. Stand mixers typically employ a planetary mixing action, which is more effective when compared to the mixing action used by mechanical and electric mixers. However, stand mixers are comparatively large, and so are not as convenient as handheld mixers. 
         [0004]    This disclosure seeks to overcome or substantially mitigate the foregoing problems with known mixers. 
       SUMMARY 
       [0005]    According to an aspect of the disclosure, there is provided a handheld apparatus for mixing food product comprising a manual input, that is an input configured to be manually operated, and a drive means or structure comprising a drive input, wherein the manual input is operatively connected to the drive input to actuate the drive structure, the drive structure further comprising first and second drive outputs operatively coupled to the drive input, each output being adapted to hold the spindle of a beater, wherein the drive structure is arranged to simultaneously rotate the first drive output in a first direction and rotate the second drive output in a second direction and rotate both drive outputs in the second direction about the central axis of the apparatus, such that the number of revolutions completed by the first drive output is less than the number of revolutions completed by the second drive output each time the drive outputs complete a revolution about the central axis. The combination of the opposing rotational movements of the drive outputs together with their collective rotation about the central axis of the apparatus means that when connected to the drive outputs, the beaters function to draw in the food product to be mixed. Moreover, the relative tangential velocity at any point on the beater heads constantly varies. This mixing action improves the mixing efficiency of the apparatus when compared to known mechanical mixers, whilst also achieving a compact design that is convenient for a user. 
         [0006]    Preferably, the drive outputs are diametrically opposed. 
         [0007]    Preferably, the drive outputs are separated by a distance meaning the rotational planes of the beater heads of the beaters overlay when the beaters are held in the drive outputs. More preferably, the distance separating the drive outputs is 28 mm and the maximum diameter of each beater head is 40 mm. 
         [0008]    Preferably, the drive outputs are pinion gears and the drive structure further comprises one or more idler gears engaged with the second drive output. 
         [0009]    Preferably, the drive structure further comprises an annular gear engaged with the first drive output and the one or more idler gears. 
         [0010]    Preferably, the first drive output and the one or more idler gears are arranged to move around the annular gear. 
         [0011]    Preferably, the positions of the first drive output and the one or more idler gears are fixed with respect to the drive input such that that movement of the drive input with respect to the annular gear causes the first drive output and the one or more idler gears to move around the annular gear. 
         [0012]    Preferably, the manual input and the drive input are connected by two bevel gears. More preferably, the two bevel gears have a gear ratio of 1/3. 
         [0013]    Preferably, the gear ratio between the annular gear and the drive outputs is 1/3. 
         [0014]    Preferably the apparatus further comprises a support bar arranged to extend around the beaters when the beaters are held in the drive outputs. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The above and other aspects of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: 
           [0016]      FIG. 1  is a perspective view of a mixer; 
           [0017]      FIG. 2  is a perspective part-sectional view of the mixer of  FIG. 1 ; 
           [0018]      FIG. 3  is a top plan view of a drive structure for the mixer of  FIG. 1 ; and 
           [0019]      FIG. 4  is a bottom plan view of the mixer of  FIG. 1 . 
       
    
    
       [0020]    In the drawings, like parts are denoted by like reference numerals. 
       DETAILED DESCRIPTION 
       [0021]      FIG. 1  shows an embodiment of a mixer, generally designated by  2 . The mixer  2  comprises a handle  4  positioned at the upper end of a generally annular housing  6 . The handle  4  includes sections made of a thermoplastic elastomer in order to provide additional grip for a user. Two identical removable rotary beaters, designated by  8  and  11 , axially extend from a base  9  of a drive means or structure, generally designate by  18 , positioned at the lower end of the annular housing  6 . Each beater  8 ,  11  includes a beater spindle  10  and a beater head  12  connected to the end of the beater spindle  10  remote from the housing  5 . In the embodiment shown, each beater head  12  is formed from two loops, which are arranged to substantially axially extend from the beater spindle  10  and terminate at the point at which the two loops cross perpendicularly with respect to each other. However, it will be apparent to those skilled in the art that the beater heads  12  could be formed from a single loop, or three or more loops. A removable support bar  20  extending around the beaters  8 ,  11  is also provided allowing the user to rest the mixer  2  on a surface, such as the floor of a bowl, during use. 
         [0022]    With reference to  FIG. 2 , the mixer  2  further comprises a rotatable crank arm  14 , a section of which is arranged to extend horizontally across the interior of the housing  6 , while the other end is connected to a grip  16 . The grip  16  is configured to rotate about the end of the crank arm  14  for the user&#39;s convenience when rotating the crank arm  14 . Two bevel gears  22 ,  24  are located in the interior of the housing  6 . The first bevel gear  22  is fixedly mounted on the horizontal section of the crank arm  14 . That is, the first bevel gear  22  is fixed with respect to the cranked arm  14  so as to prevent relative moment therebetween. The second bevel gear  24  is fixedly mounted on a central shaft  26  extending along a central axis of the mixer  2 . The central shaft  26  is substantially perpendicular to the horizontal section of the crank arm  14  extending across the interior of the housing  6 . 
         [0023]    In use, the user holds the mixer  2  by the handle  4  with one hand and uses the grip  16  to rotate the crank arm  14  with their other hand. The rotary motion of the crank arm  14  is transferred by the bevel gears  22 ,  24  to the central shaft  26 . The rotary motion of the central shaft  26 , in turn, drives the drive structure  18  to rotate the beaters  8 ,  11  about their respective axes. That is, the central shaft  26  functions as the input for the drive structure  18 . The first bevel gear  22  comprises 30 teeth and the second bevel gear  24  comprises 10 teeth resulting in a gear ratio of 1/3. That is, the crank arm  14  must make one revolution to turn the second bevel gear  24 , together with the central shaft  26 , three times. 
         [0024]      FIG. 3  shows the drive structure  18  located in the lower section of the housing  6  comprising the central shaft  26 , the base  9  and an annular gear  28  fixed to the internal surface of a stationary gear housing  38 . The annular gear  28  is concentrically aligned with the central shaft  26 . The drive structure  18  further comprises four pinion gears  30 ,  32 ,  34 ,  36 . The first and second gears  30 ,  32  function as the output gears for the drive structure  18 , each comprising a socket member (not shown) adapted to hold one beater spindle  10  in a rotationally fixed relationship. In the embodiment shown, the first and second gears  30 ,  32  are adapted to receive the beater spindle  10  of the first and second beaters  8 ,  11  respectively. The third and fourth gears  34 ,  36  function as idler gears. The teeth of the first gear  30  directly engage or mesh with the teeth of the annular gear  28 . While the teeth of the second gear  32  engage with the teeth of the third and fourth gears  34 ,  36  which, in turn, engage with teeth of the annular gear  28  to establish a gear train between the annular gear  28  and the second gear  32 . That is, there is no direct engagement between the second gear  32  and the annular gear  28 . The third and fourth gears  34 ,  36  function to reverse the rotation of the second gear  32  with respect to the rotation of the first gear  30  and also stabilise the second gear  32  when it is rotating. In the embodiment shown, the second gear  32  is positioned above the plane of the annular gear  28 . However, it will be apparent to those skilled in the art that the second gear  32  could be positioned below the plane of the annular gear  28 . 
         [0025]    The drive structure  18  further comprises two posts  40 ,  42  that function to maintain the vertical distance between the base  9  and the top of the gear housing  38  of the drive structure  18 . The base  9  is connected to the central shaft  26 , preventing relative rotation therebetween. That is, the central shaft  26  and the base  9  are configured to rotate about the central axis of the mixer  2  at the same angular velocity when the crank arm  14  is rotated. The gears  30 ,  32 ,  34 ,  36  are mounted to the base  9  of the drive structure  18 , and so are held in a fixed positional relationship with respect to the base  9 . Accordingly, the gears  30 ,  32 ,  34 ,  36  collectively rotate about the central axis of the mixer  2  in an orbital path when the crank arm  14  is rotated. The collective movement of the gears  30 ,  32 ,  34 ,  36  through the orbital path, with respect to the annular gear  28 , causes the meshing gears, that is, the first, third and fourth gears  30 ,  34 ,  36 , to move around the annular gear  28  and, consequently, simultaneously rotate about their respective axis. The second gear  32  is also caused to simultaneously rotate about its axis while moving through the orbital path by its meshing with the third and fourth gears  34 ,  36 . 
         [0026]    From the viewpoint shown in  FIG. 3 , the central shaft  26 , and so the base  9 , is arranged to rotate in a clockwise direction. Accordingly, the first, second, third and fourth gears  30 ,  32 ,  34 ,  36  are also configured to move collectively through the orbital path, together with the posts  40 ,  42 , in a clockwise direction. This movement causes the first, third and fourth gears  30 ,  34 ,  36  to rotate about their respective axis in an anticlockwise direction, while the second gear  32  rotates in a clockwise direction. It will be apparent to those skilled in the art that the central shaft  26  could equally be rotated in an anticlockwise direction, which would reverse the direction in which the gears  30 ,  32 ,  34 ,  36  rotate. In the embodiment shown, the annular gear  28  has 30 teeth and the first, second, third and fourth gears  30 ,  32 ,  34 ,  36  each have 10 teeth. This results in a gear ratio of 1/3 between the annular gear  28  and the first and second gears  30 ,  32 . That is, the first and second gears are configured to revolve three times each time they move around the annular gear  28  based on the gear ratio only. 
         [0027]    The first and second gears  30 ,  32  are positioned diametrically opposite each other within the housing  6  and are separated by a distance that is less than the maximum width, but greater than half the maximum width of the beater heads  12 . In the embodiment shown, the maximum diameter of the beater heads  12  is 40 mm and the distance separating the first and second gears  30 ,  32  is 28 mm. This arrangement creates a region in which the respective rotational planes of the beater heads  12  cross or partially overlay such that the loops of the beater heads  12  are interposed or intercalated when the beater spindles  10  are inserted into their respective socket member, as shown in  FIG. 4 . From the view point shown in  FIG. 4 , which is opposite to the view point of  FIG. 3 , the base  9  and the second beater  11  are configured to rotate in an anticlockwise direction, and the first beater  8  is configured to rotate in a clockwise direction. The anticlockwise rotation of the base  9 , causing the orbital rotation of the beaters  8 ,  11 , coupled with the simultaneous rotation of the first and second beaters  8 ,  11  about their respective axis has the effect of relatively decreasing and increasing the number of revolutions completed by the first and second beaters  8 ,  11  respectively per revolution of the base  9 . In the embodiment shown, the first and second beaters  8 ,  11  are arranged to revolve two and four times respectively for every revolution completed by the base  9 . 
         [0028]    The opposing rotational movements of the beaters  8 ,  11  about their respective axis function to draw food product to be mixed between the beaters  8 ,  11  and into the region where the rotational planes of the beater heads  12  overlay. The orbital movement of the beaters  8 ,  11  also functions to draw the food product between the beaters  8 ,  11 , in addition to constantly varying the relative tangential velocity at any point on the loops of the beater heads  12 . This exposes the food product to fluctuating shearing forces created by the loops of the beater heads  12  moving through the region, creating a turbulent area for mixing the food product. This improved mixing action means that the user can hold the mixer  2  stationary with respect to the vessel containing the food product to be mixed without sacrificing mixing efficiency. 
         [0029]    It will be apparent to those skilled in the art that various modifications may be made to the described embodiment without departing from the scope of the invention as defined by the accompanying claims.