Milkshake mixer blade

An improved mixing blade which can be substituted for mixing blades of existing milkshake machines, including a generally planar body portion having a central aperture for attachment to a mixer shaft, the body portion terminating in a pair of opposed straight edge portions each having an upturned tab element along at least one end thereof, and a pair of curved edge portions each having a downturned skirt along their entire length.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to food processing equipment, and more 
specifically to electric drink mixers, particularly those used to make 
milkshakes. 
2. Description of the Prior Art 
Known milkshake mixers currently in use consist basically of an electric 
motor mounted on a stand, with a downwardly-dependent rotating shaft to 
which is affixed at least one and typically two disk-shaped mixing blades 
(the upper of which is usually press-fit onto the shaft, while the lower 
blade is typically screwed on to the bottom of the shaft). These mixing 
blades have a rippled edge, which creates turbulence as they rotate, 
thereby mixing the milk, ice cream and other ingredients within the 
milkshake canister. 
However, the amount of turbulence produced by these blades of the prior art 
is insufficient to do either a rapid or thorough job of blending the milk 
and chunks of ice cream which are the ingredients of most milkshakes. As a 
result, an attendant must continually manipulate the milkshake canister up 
and down and back and forth relative to the rotating shaft and blades in 
order to achieve a thorough mixing of the ingredients. When hard ice cream 
is used, this process can take five or six minutes or more, during which 
time the attendant is occupied with this procedure and therefore not free 
to deal with other customers or their orders. Despite this aggravating and 
time-consuming process, the end result is often a milkshake still 
containing lumps of ice cream, and if the ice cream contained bits of ice 
to begin with (as is not uncommon), these bits of ice are also still 
present in the final product. 
SUMMARY OF THE INVENTION 
The milkshake mixer blade of the present invention provides an improved 
mixing blade which can easily be substituted for mixing blades of the 
prior art, thereby converting today's slow, inefficient milkshake 
machines, requiring constant attention, into highly efficient mixers which 
can produce a smooth, completely blended milkshake in two minutes or less, 
with no manual agitation. The inventive blade includes a generally planar 
body portion having a central aperture for attachment to a mixer shaft, 
the body portion terminating in a pair of opposed straight edge portions 
each having an upturned tab element along at least one end thereof, and a 
pair of curved edge portions each having a downturned skirt along their 
entire length, such that the respective edge portions define reversed 
mirror images of each other relative to an axis drawn through the central 
aperture. 
The inventive blade achieves its superior results by creating a vigorous 
rotating double-torus flow pattern within the milkshake canister, with a 
vortex superimposed from the top down. Since the inventive blade is 
designed to preferably replace only the lower of the two disk-like mixing 
blades usually present on current milkshake machines, the following 
description will refer to "blades" in the plural: 
The fluid flow patterns created by the combined actions of the two blades 
blend together into one highly efficient mixing stream. As fluid is thrown 
radially outward (centrifugally) by the rotating blades, part of the fluid 
is deflected spirally downward by the tapered wall of the milkshake 
canister. When it reaches the bottom of the canister, this circular and 
downward flow spirals in toward the center, and then upward and outward 
once again. The portion of the rotating mixture which is not deflected 
downward by the canister wall is deflected circularly upward instead. When 
the fluid reaches the top of the fluid column, it is sucked radially 
inward (centripetally) into the vortex created by the whirling blades. 
Along with entrained air, the fluid then moves downward to the blades, and 
is thrown outward once again. This vigorous flow pattern, which is made 
increasingly turbulent by entrained air as the speed of rotation rises, 
includes the entire liquid volume of the mixing canister, and is 
responsible for the rapid and thorough blending which is achieved by the 
present invention. This flow pattern is enhanced by both the up-turned 
tabs and the down-turned skirts of the inventive blade design.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
FIG. 1 is an upper frontal left perspective view of a milkshake mixer blade 
10 of this invention, illustrating its generally planar body portion 12 
bearing a central aperture 14 for attachment to a mixer shaft (not shown). 
The body portion 12 is generally defined by four sides A, B, C and D as 
follows: the body portion terminates in a pair of opposed straight edge 
portions 20a, 20b each bearing an upturned tab element 22a, 22b adjacent 
only one end 24a, 24b of each of the straight edge portions 20a, 20b. The 
body portion 12 is further defined by and terminates in a pair of curved 
edge portions 26c, 26d each bearing a downturned skirt element 28c, 28d 
along the entire lengths of the curved edge portions, such that the 
respective edge portions 20a, 20b and 26c, 26d define reversed mirror 
images of each other relative to an axis drawn through the central 
aperture 14. The arrows indicate the preferred direction of rotation of 
the blade when installed. 
FIG. 2 is a front elevation view of the milkshake mixer blade 10 of this 
invention, while FIG. 3 is a right side elevation view of the milkshake 
mixer blade 10 of this invention. These views illustrate the symmetrical 
relationship of the upturned tab elements 22a, 22b and downturned skirt 
elements 28c, 28d. Tab elements 22a, 22b are preferably approximately 
one-third the length of the straight edge itself. 
FIG. 4 is a top plan view of the milkshake mixer blade 10 of this 
invention, while FIG. 5 is a bottom plan view of the milkshake mixer blade 
10 of this invention. 
FIG. 6 is a schematic side elevation view of a typical milkshake mixer 
apparatus 40 in operation with the milkshake mixer blade 10 of this 
invention installed on a downwardly-depending mixing shaft 42 some 
distance beneath a prior art mixing blade 44. 
While this invention has been described in connection with preferred 
embodiments thereof, it is obvious that modifications and changes therein 
may be made by those skilled in the art to which it pertains without 
departing from the spirit and scope of the invention. Accordingly, the 
scope of this invention is to be limited only by the appended claims and 
their legal equivalents.