The present invention is directed to a blender blade assembly and a respective blender.

Current blenders in the market need to deal with different in ^¬ gredients and recipes and be capable of liquefying, mixing and producing different textures. In most of cases, the performance of the blenders is measured in the final particle size after processing during certain period of time.

Therefore, the circulation inside the blender jar and the effi ^¬ ciency of the blades arranged in the blades assembly has a lot to do with achieving good results. One of the most difficult tasks when processing food in a blender is having to process viscous ingredients or recipes, such as smoothies, milkshakes or slushies, because the circulating movement is reduced, and the demand of power and efficiency from the motor and blades is in- creased. The viscosity of such ingredients also reduces the suc ^¬ tion carried by the vortex, and an air pocket can be formed above the blades, causing them to spin without processing nearby food . To avoid the formation of air pockets, it is known to use plung ^¬ ers by which the user can interact in a stirring movement and thus help to explode or remove the air pocket.

Further it is known to avoid or remove air pockets by improving the suction in the vortex by increasing the speed of the blender blades or adding more liquid to the mixture.

However, all these solutions bring unconformities to the user as in the first case, the user needs to intervene. In the second case, where in most cases rotational speeds of over 20,000 rpm are used, comparatively high noise levels, that are generally difficult to remove, are generated. And the third case the final result could be affected in quality of textures and flavour due to the addition of more liquid.

Apart from the above solutions it is known to generate non ^¬ uniform vortices within the blender jar, for example by using special blender blade and/or jar geometries. Another issue identified on the performance of blenders for ex ^¬ ample is the formation of ice bridges below the blender blade during processing frozen items, such as ice cubes. In general this issue relates to the aggregation of particulate matter be ^¬ low the blender blade during operation.

As can readily be seen, there is still need for improving blend ^¬ ing or mixing results and vortex generation in conventional blenders . It is one of the objects of the present invention to solve the inconveniences observed with state of technology. In particular, it is an object of the invention to provide solutions for achieving improved blending, mixing and vortex generation in blender jars of blenders.

This object is solved by claims 1 and 11. Embodiments result from respective dependent claims.

According to claim 1, a blender blade assembly is provided hav- ing a first blade with two first blade arms extending from a centre plane in opposite directions, wherein each blade arm com ^¬ prises a planar base section extending perpendicularly from the centre plane, wherein the base section merges at its outer end into a wing section angled upwards from the base section, and wherein the blade assembly further comprises a second blade with two second blade arms, wherein each second blade arm comprises a curve shaped blade.

Each of the first blade arms comprises a planar base section ex- tending perpendicularly from the centre plane. Note that the term "planar" in particular can be understood in the meaning of straight, flat and non-twisted. The base sections of the two blade arms start tangentially to the edge of the planar surface. Each of the second blade arms is generally flat or planar all throughout their extension. The curve shaped (C-shaped) blade which describes a curved shape, is sharpen on top. Further it is arranged parallel to the bottom surface of the blender jar. The curved shape, is advantageous to guide pieces (of foodstuff) stuck on the bottom surface of the blender jar. The pieces are guided to the end of the curve shaped blade and thus closer to the blender jar walls. This increases the opportunities for the pieces to get back to the vortex or to be sliced when close to the blender jar walls.

With the proposed first blender blade, the base section merges at its outer or distal end, i.e. at the end averted from the centre plane, into a respective wing section, preferably also of planar configuration. Each of the wing sections is angled up- wards from the respective base, i.e. the wing section is ori ^¬ ented aslant to the respective base section.

Regarding the mutual arrangement of the base section and the wing section, the first blade can be described as having a trough-shaped cross section in planes perpendicular to the cen ^¬ tre plane and base sections.

With the proposed first blender blade it is further provided that each wing section is twisted such that a buckling line be- tween the wing section and its related base section intersects the centre plane in an acute angle.

The twist of the wing section is closely related to the angle of attack of the cutting blade wing section, i.e. the attacking angle with which the wing section impinges or acts on substances to be mixed or blended. The angle of attack or attacking angle can advantageously be used for influencing, in particular improving, drag and lift forces and in turn influencing vortex generation, aeration and mixing.

With the proposed structure and geometry of the blender blade assembly, in particular first and second blade arms, it is pos ^¬ sible to obtain advantageous drag and lift forces for a great variety of different blender jar geometries. Drag and lift forces in particular can be optimized in order to obtain optimal mixing. Further, with the proposed blender blade assembly geome ^¬ try, the formation of air pockets in viscous substances around or above the blender blade can at least greatly be avoided or reduced.

The proposed blender blade assembly, in particular having a first blade with preferable trough-shaped cross section and a second blade being curve shaped, is particularly suitable for jars having a flat surface below the blades swept area at which the blender blade assembly is to be operated in a rotational movement .

According to an embodiment of the blender blade assembly, the first blade wing section merges at its outer end into a winglet section. Hence, each first blade arm comprises a winglet section which is arranged and positioned at the outer and upper end of the respective first blade arm. Preferably, the winglet section is running or oriented essentially parallel to the centre plane. With winglet sections as proposed, it is possible to effectively reduce vortices generated at the end of the first blade arms during operation of the blender blade assembly. This in turn results in a better performance and in improved blending and mix- ing .

According to a further embodiment of the blender blade assembly, each blade arm comprises a cutting edge respectively starting essentially at the centre plane and running along a leading edge of each blade arm at least over the base section and wing sec ^¬ tion. If applicable, i.e. if a winglet section is provided, the cutting edge preferably also extends, at the leading edge, at least partially over the winglet section. The leading edge of a blade arm shall mean the face side that impinges and acts on substances during ordinary operation, i.e. rotation, of the blender blade.

It is preferred that the cutting edge is implemented at an upper side of respective sections of the blender blade. In this con- figuration, a sharpen or bevelled edge is formed on or at the upper side or surface of the blender blade.

The proposed design of the cutting edge is effective in obtain ^¬ ing homogenous mixing results and therefore optimal blending and mixing of viscous substances, slurries and solid-liquid mix ^¬ tures. Further, and also with the features and characteristics given above, advantageous performance and power demand for oper ^¬ ating the blender blade can be obtained. According to a further embodiment, an inclination angle by which the wing section is angled upwards, in particular upwards from a plane parallel to the base section and perpendicular to the cen ^¬ tre plane, may be in the range between 10 degrees and 60 de ^¬ grees. Preferably, the inclination angle is selected in depend- ence of or determined by at least one of a bottom cross section, bottom diameter and bottom curvature of a blender jar intended for operating the blender blade therein, i.e. a blender jar in which the blender blade is intended to be operated. Respective angles, preferably adapted to certain geometrical pa ^¬ rameters of the blender jar, such as diameter near or at the jar bottom or shape of the jar bottom, are favourable for obtaining optimal mixing and blending and performance. In a further embodiment, a twist angle by which the buckling line intersects the centre plane lies in the range between 1 de ^¬ grees and 90 degrees, and preferably is selected in dependence of at least one of a bottom cross section, bottom diameter and bottom curvature of a blender jar intended for operating the blender blade therein. Twist angles within the mentioned range and/or selected in dependence of the mentioned parameters are of particular advantage for generating optimal drag and lift forces and allowing comparatively high mixing and blending efficiencies .

According to claim 11, a blender, in some instances also designated as mixer, or mixing device, is provided which comprises a blender jar, i.e. a blender or mixing vessel or container, and a blender blade according to any embodiment and variant as de- scribed further above.

With the proposed blender, the blender blade assembly is rotata- bly attached at a bottom site of the blender jar. As to advantages and advantageous effects, reference is made to the description above and further below relating to the blender blade assembly. In particular, the proposed blender offers sig ^¬ nificant improvement in blending and mixing efficiency, in par ^¬ ticular due to the fact of improved drag and lift forces and vortex generation. This in particular applies for blender jars having a jar bottom of concave, in particular semi-spherical or a flat bottom jar shape, preferably in connection with a blender blade of trough-shaped cross section. In an embodiment of the blender, an axis of rotation of the blender blade within the blender jar is tilted from the perpendicular axis of a working surface, wherein the working surface is defined by the ordinary operational position of the blender. Note that the axis of rotation of the blender blade assembly ac- cording to the present invention preferably is perpendicular to the base section and lies within the centre plane of the blender blades. Tilting the axis of rotation of the blender blade assembly as proposed beforehand, leads to improved mixing and blend ^¬ ing efficiency. In particular, vortex generation and circulation of the substances within the blender jar can greatly be im ^¬ proved .

In an embodiment of the blender, a tilt angle of the axis of ro ^¬ tation lies in the range from 5 degrees to 20 degrees. Tilt an- gles as mentioned beforehand have proven advantageous for effi ^¬ cient mixing and blending substances within the blender jar.

In all it can be seen, that the blender blade assembly and blender provide superior mixing and blending results. In par- ticular, the vortex generation can be improved and optimized, which in the end will lead to a better performance of the blender. Moreover, the proposed blender blade assembly and blender provide improved circulation of ingredients inside the blender jar, optimized power consumption, in particular due to optimized drag and lift forces. Further, with the proposed blender blade assembly, unnecessary splashing and spilling of products or substances, such as liquids, in or from the blender jar can be greatly avoided. The angle of attack essentially represented by the twist angle of the wing sections can directly influence the drag and lift forces. Setting suitable angles of attack can improve the aera ^¬ tion and produce bigger vortices. Note that the bigger the angle of attack, the bigger the drag and lift forces. This is due to the fact that for bigger angles of attack, increased surface ar ^¬ eas for "pushing" the fluids within the jar are available, which will cause the liquids to move faster and higher inside the blender jar. Reducing the angle of attack decreases drag and lift forces, and also splashing and possible spilling. Conse ^¬ quently, a beneficial turbulence optimized for optimal perform ^¬ ance can be obtained. In particular, optimized performance can be obtained for hard ingredients in liquids and viscous sub ^¬ stances .

In addition, it shall be mentioned that improved drag and lift forces in general will cause the motor driving the blender blade to be more efficient, which will lead to reduced power consump ^¬ tion.

Operating the proposed blender blades assembly in a blender jar of flat bottom shape not only optimizes vortex generation and mixing in the volume above the blender blade, but also will lead to optimized circulation and recirculation in the volume below the blender blades or in isolated or narrow corners of the blender jar.

Therefore, the design of the blender blade assembly is effective in generating optimized drag and lift forces, and also in ob- taining optimal sized and shaped vortices within the blender jar. The shape and configuration of the proposed blender blade assembly gainfully improves the final result of mixing and blending, and in addition is effective in reducing the power consumption of a motor driving the blender blade within the blender jar. Embodiments of the invention will now be described in connection with the annexed figures, in which. FIG. la shows a perspective view of a blender blade assembly according to an embodiment,

FIG. lb shows an exploded view of the blade assembly of FIG.

la,

FIG. lc shows an exploded view of an embodiment of the blade assembly of FIG. la,

Fig. 2 shows a section of a blender jar comprising the blade assembly of FIG. la,

FIG. 3 shows a perspective view of an embodiment of a blender blade for a blender blade assembly; FIG. 4 shows a side view of the blender blade of FIG. 3;

FIG. 5 shows a top view of the blender blade of FIG. 3; and

FIG. 6 shows a section of a blender comprising a blender

blade according to FIG. 3 to FIG. 5.

Unless otherwise mentioned, like elements are designated by like reference signs throughout the figures. FIG. la shows an embodiment of a blender blade assembly. The blade assembly 18 comprises a first blade la, described in de ^¬ tail below with reference to FIG. 3-6. The first blade la has two symmetrical first blade arms 2a arranged for reaching out ^¬ wardly and upwardly. On top of the first blade la the second blade lb is arranged. The second blade is generally flat and has a curved outer shape (C-shape) on each second blade arms 2b. he C-shaped blade is sharpen on top. In the embodiment illustrated in FIG. lb, the second blade 2a comprises two separate pieces or second blade arms 2b that are arranged on top of each other in the blades assembly, forming an S-shaped blade. In this way two levels of chopping or cutting areas are created. The second blade lb may also be made out of a single piece of material as shown in FIG. lc. In this embodiment the second blade arms 2b are arranged opposite each other on the same level. Generally, the C-shaped blade sweeps the bottom of a blender jar, such that possible residue stuck in the corners are reduced and integrated back to the vortex.

The blade assembly 18 may also comprise a third blade lc ar- ranged on top of the first and second blades. The third blade lc comprises third blade arms 2c arranged upwardly reaching from a planar base section. The third blade is particularly added in blender jars having a wide bottom as the distance between the winglets of the first blade la can be far from each other, and could allow ingredients to bounce within the upper surfaces of the blade, without being processed. The third blade lc may be added on top of the other blade, to cover the centre of the blender vortex. The third blade arms 2c may be bent in different angles depending on the particular jar geometry and relation to the other blades. In some embodiments the blender jar is pro ^¬ vided with an vertical rib on the inside of the jar wall which may co-operate with the third blade lc. The rib may divert the circulation and throw the ingredients to the centre of the blender jar, and the ingredients are received and sliced by the third blades lc.

FIG. 3 shows a perspective view of an embodiment of a blender blade 1 of the present invention. The blender blade 1 has two blade arms 2. The blade arms 2 extend from a common (virtual) centre plane 3. The centre plane 3 centrically crosses a mount- ing hole 4 provided for mounting the blender blade 1 to a driving unit or driving shaft of a blender. The illustrated blade may be used alone as a single blade in a blades assembly as il ^¬ lustrated in FIG. 6, or as a first blade as one of several blades in a blades assembly similar to the one described in re ^¬ lation to FIG. la-c and 2.

Each of the blade arms 2 comprises a planar base section 5 ex ^¬ tending perpendicularly from the centre plane 3. With the first blade la, the base section 5 merges at its outer end 6 into a wing section 7.

The wing section 7 is angled upwards from the base section 5 as can be seen in more detail in FIG. 4 showing a side view of the blender blade 1. In particular, the wing section 7 is angled upwards relative to a plane defined by the base sections 5. The angle a by which the wing section 7 is angled upwards preferably lies in the range between 10 degrees and 60 degrees. Preferably, the angle a is selected and adapted in accordance with at least one geometrical parameter of a blender jar in which the first blade la is intended to be operated. Such a pa ^¬ rameter may in particular be at least one of a bottom diameter, bottom curvature and bottom cross section of a respective blender jar.

The wing sections 7 of the first blade as shown in FIG. 3 are twisted such that a buckling line 8 between the base section 5 and the wing section 7 intersects the centre plane 3 in an acute twist angle φ . This configuration can readily be seen from FIG. 5 showing a top view of the first blade la.

The configurations and shapes that may be implemented for the blender blade 1 as shown in the figures in particular are ade- quate for generating favourable drag and lift forces in a sub- stance, in particular viscous substance, in turn leading to enhanced mixing and blending results, in particular for hard ingredients in liquids and viscous substances. Further, the blender blade configuration provides enhanced performance and allows power optimized operation of a respective blender.

As can be best seen from FIG. 3 and FIG. 4, the wing section 7 of each first blade arm 2a merges at its upper end 9 into a winglet section 10. The winglet section 10 in the present em- bodiment is oriented upwards and is running essentially parallel to the centre plane 3. The winglet section 10 as implemented with the first blade la is effective in reducing turbulences generated by vortices at the end of the first blade arms 2a dur ^¬ ing operation. This leads to improved and more efficient mixing and blending.

With the first blade la of the present embodiment, each first blade arm 2a comprises a cutting edge 11 respectively starting at the centre plane 3 and running along a leading edge 12 of each first blade arm 2a, which can be best seen in FIG. 2 and

FIG. 4. The cutting edge 11 in the present case respectively ex ^¬ tends at the leading edge 12 over the base section 5, the wing section 7 and the winglet section 10. In this case, a sharpen or bevelled edge is present at the upper side of the first blade la. Providing the cutting edge 11 at the upper side of the blender blade has been proven to result in enhanced blending results, in particular for the proposed geometry and shape of the first blade la.

With regard to the twist angle φ it is of particular advantage if the twist angle is selected in dependence of at least one of a bottom cross section, a bottom diameter and a bottom curvature of a blender jar in which the first blade la is to be operated. Adjusting the twist angle φ to the geometric and structural con- figuration of the blender jar in particular leads to enhanced mixing, blending and vortex generation.

Referring now in particular to FIG. 6 showing section of a blender 14, the first blade la is provided at a bottom side of a blender jar 15. The blender blade la is attached rotatably around an axis of rotation 16 to the bottom side of the blender jar 15. The bottom of the blender jar 15 in the present case has a semi spherical shape described by the swept area below the blade, and the angle a is selected in dependence of the diameter and curvature of the bottom of the blender jar 15.

In particular with reference to FIG. 6 it can be seen that accu ^¬ mulation of particulate matter at the bottom of or below the blender jar 15 during mixing can be greatly avoided by adequately selecting the geometry of the blender blade la. Further, vortex circulation and distribution over the blender jar 15 can be optimized, in particular by matching the blender blade geome ^¬ try and shape parameters to the blender jar bottom geometry.

Further reference is now made to FIG. 6, in which the ordinary operational position of the blender jar 15 and first blender blade la is shown in more detail. In FIG.6, the orientation of a working surface on which the blender during ordinary operation will be or is positioned is schematically indicated by a hori ^¬ zontal broken line.

The axis of rotation 16 of the first blade la within the blender jar 15 is tilted from a normal axis 17 of the working surface by a tilt angle γ. A tilt arrangement of the blender blade la rela ^¬ tive to the normal axis 17 has been proven advantageous for op ^¬ timizing vortex generation in blending and mixing procedures. In particular, static areas in which vortex generation within the blender jar 15 will be constrained can be greatly avoided. In addition, accumulation of particulate matter between the blender blade la and the bottom of the blender jar 15 can largely be prevented .

The tilt angle γ by which the axis of rotation 16 of the blender blade la is tilted against the normal axis 17 of the working surface preferably lies in the range between 5 degrees to 20 de ^¬ grees. Such angles turned out to provide optimal and efficient mixing and blending results, in particular with spherical-shaped bottom geometries.

In all and in particular with reference to the figures, the blender blade assembly 18 and first blender blade la as proposed herein is suitable for obtaining enhanced mixing and blending results. Further, the performance and power consumption of a blender utilizing a respective blender assembly 18 can be opti ^¬ mized.

List of reference numerals la, lb, lc blender blades

2a, 2b, 2c blade arms

3 centre plane

4 mounting hole

5 base section

6 outer end

7 wing section

8 buckling line

9 upper end

10 winglet section

11 cutting edge

12 leading edge

13 bottom side

14 blender

15 blender jar

16 axis of rotation

17 normal axis

18 blender blade assembly

a angle

Φ twist angle

Y tilt angle