Claims:PATENT CLAIMS

1. Blade assembly (100, 200) for a mixer grinder (1) comprising:

- at least one blade (13),
- a cap (101, 201) with actuation means (102, 202),
- an engaging mechanism (EM1, EM2) comprising projections (106, 206) and connecting the actuation means (102, 202) to the projections (106, 206),
characterised in that the projections (106, 206) of the engaging mechanism (EM1, EM2) are configured to be received in holes (105, 205) of a spindle (8) for coupling the blade assembly (100, 200) to the spindle (8).

2. Blade assembly (100) according to claim 1, characterised in that the engaging mechanism (EM1) comprises a pair of levers (103) and a biasing means (104).

3. Blade assembly (200) according to claim 1, characterised in that the engaging mechanism (EM2) comprises a pair of rods (203) and a pair of biasing means (204).

4. Blade assembly (200) according to claim 2 or 3, characterised in that the biasing means (104, 204) is a spring.

5. Blade assembly (200) according to any of the preceding claims, characterised in that the actuation means (102, 202) is a button.

6. Blade assembly (100) according to claim 5 when depedent on claim 2, characterised in that the button is push button.

7. Blade assembly (200) according to claim 5 when depedent on claim 3, characterised in that the button is pull button.

8. Blade assembly (100, 200) according to any of the preceding claims, characterised in that the holes (105, 205) form a through hole.

9. Blade assembly (100, 200) according to any of the preceding claims, characterised in that the cap (101, 201) is shaped as a prism with hexagonal base.

10. Blade assembly (100, 200) according to any of claims 1-8, characterised in that the cap (101, 201) is shaped as a cylinder.

11. Blade assembly (100, 200) according to any of the preceding claims, characterised in that the cap (101, 201) is made of plastic material.

12. Blade assembly (100, 200) according to any of the preceding claims, characterised in that the blades (13) are preferably of the same shape.

13. Mixer grinder (1) comprising:

- a base appliance (5) and
- a jar (2) comprising blade assembly (100, 200) according to any of the preceding claims.
, Description:Description

Background of the invention

The present invention relates to a mixer grinder, more particularly to blade assembly for a mixer grinder.

State of the Art

Mixer grinders and juicer grinders as kitchen appliances are becoming ever popular. More so as they are powerful and versatile so that they are capable of processing food in many ways, for instance in particular they are suitable for preparing all sorts of chutneys (coconut, coriander) and for dry grinding of turmeric, coriander seeds, cumin and for wet grinding which means preparing batters, tomato purees and smoothies and the like.

It is known it the art to use a metal jar with blenders, mixer grinders and juicer grinders. Such a metal jar is mostly made of stainless steel. This brings many benefits to a user. Namely, it’s durable, versatile, odor-resistant, non-reactive, and easy to clean. Moreover, it‘s suitable for processing tough vegetables, seeds and spices (i.e. turmeric, cumin, coriander seeds) without a fear for the surface of the jar getting scratches or dents, bumps, impressions and the like. In order for the surface to withstand all these loads and stresses the wall of the jar has to be thick enough. That being said, the jar has to be made of 0.6-0.8 mm thick steel sheet.

However, on such a jar it is practically impossible to make a thread on its bottom for attaching a socket with the blades in a rotational manner. Even other attaching possibilites are not feasible as metal sheet of such a thickness is hard to work or (de)form.
Hence, the socket has to be permanently attached to the jar. This means, the knife with the blades has to be made removable from the interior of the jar. In most cases the knife is threadedly connected to a drive shaft or a spindle. After prolonged and/or heavy use, the connection of the knife to the shaft can get so tight that it’s very difficult to remove it. A lot of effort and time is needed in order to remove the knife. Such a situation can lead to unforeseen, unpleasant and even dangerous situations like cutting fingers.

The solution to this drawback is to make the knife or the blade assembly easily removable from the jar of the mixer grinder, preferably without using a tool. This should be realized in the most convenient way, for instance in a form-fitting manner.

Problem to be solved

It is an object of the present invention to overcome the above-mentioned shortcomings of
the prior art and particularly to improve a blade assembly and a mixer grinder comprising such a blade assembly. The blade assembly and the mixer grinder should ensure efficient, safe and comfortable use.

Solution according to the invention

The object is achieved by the blade assembly according to the features of claim 1 and the mixer grinder according to the features of claim 13.

Advantageous embodiments that can be implemented by themselves or in combination are described in dependent claims.

The invention relates to a blade assembly for a mixer grinder comprising:

- at least one blade ,
- a cap with actuation means,
- an engaging mechanism comprising projections and connecting the actuation means to the projections,
wherein the projections of the engaging mechanism are configured to be received in holes of a spindle for coupling the blade assembly to the spindle.

The blade assembly according to the invention provides the following advantages:
- easy removal,
- firm connection to the spindle,
- no need for a force-fitting or material engagement (screwing, glueing or welding) which provides for a quicker attachment and removal and lower costs of production,
- no need for a tool,
- no risk of injury during removal,
- possibility to change a blade assembly and/or blades,
- independence from the sense/direction of rotation,
- easy cleaning of the jar.

Embodiments of the invention

According to one preferred embodiment, the engaging mechanism comprises a pair of levers and a biasing means. This is the first embodiment according to the invention. By means of the spring the levers are brought in the initial position after pushing or pressing the actuation means (buttons). Initial position means engaging position, i.e. the projections of the levers being received by the respective holes or protruding therein.

According to another embodiment of the invention, the engaging mechanism comprises a pair of rods and a pair of biasing means. This is the second embodiment according to the invention.
By means of the springs the rods are brought in the initial position after pulling the actuation means (buttons). Initial position means engaging position, i.e. the projections of the rods being received by the respective holes or protruding therein.

In an advantageous solution, the biasing means is a spring. The spring provides force needed for the actuation means (buttons) to return to the initial position. Furthermore, thereby also the levers of the first embodiment or the rods of the second embodiment are returned to the initial position.

Advantageously, the actuation means is a button. The button can be realized as a push button or a pull button. A pair of push buttons is used in the first embodiment whereas a pair of pull buttons is used in the second embodiment.

Typically, the holes form a through hole. The holes in the upper part of the spindle are concentric but arranged in a opposing manner. They are configured to receive projections of the levers or the rods. Normally, these holes are formed as blind holes. Most preferably, these holes can be joined to make a through hole. The effect is that the through hole can be cleaned in a more convenient and comfortable way.

Optionally, the cap is shaped as a prism with hexagonal base. Thus, the cap can be grabbed effectively even in case of wet conditions.

Advantageously, the cap is shaped as a cylinder. This provides for a cheap solution suitable for mass production.

The buttons of the first embodiment can be arranged higher than the buttons of the second embodiment with regard to the blades. This means more convenient and safer way to remove the blade assembly from the spindle and the jar.

In an advantageous solution, the cap is made of plastic material, preferably of nylon. In this way, production costs can be reduced.

Typically, the cap can be made of metal. In this case the cap and the blades can be joined to make an integral part or component. The cap and the blades can be joined in a force-fitting manner or applying material engagement (welding or glueing). Most preferably, they can be welded.

Optionally, the blades are of the same shape. Generally, there are 4 blades. If need be, pairs of blades can have the same shape.

All aspects of the invention outlined in the present document may be arbitrarly combined. In particular, features of the claims my be combined with one another in an arbitrary manner.

It can be understood that the invention is not limited to mixer grinders but can also be used with blenders, choppers, juicers and similar kitchen appliances.

Brief description of the figures

Fig. 1 is an isometric view of the mixer grinder
Fig. 2 is a section view of the mixer grinder comprising the blade assembly according to the first embodiment of the invention
Fig. 3 is an isometric view of the blade assembly according to the first embodiment of the invention
Fig. 4 is a section view of the blade assembly according to the first embodiment of the invention
Fig. 5 is a side view of the blade assembly according to the second embodiment of the invention
Fig. 6 is a section view of the blade assembly according to the second embodiment of the invention

Detailed description

Fig. 1 depicts a mixer grinder 1. A jar 2 is arranged on a base appliance 5 which houses electrical and electronic components (an electric motor, PCB control boards etc.) and mechanical components (a shaft or a spindle etc.) – none of these are shown in this figure. The base appliance 5 is provided with a knob 6 for controlling a type and speed of food processing of the mixer grinder 1. The jar 2 comprises a handle 4 and is covered by a lid 3. The surface of the jar is equipped with a recess R. This recess R is a flow breaker protruding into the interior of the jar 2 to improve flow properties of the food being processed. The mixer grinder 1 is supported on suction feet 7 which are intended for stabilisation during use. The jar 2 is made of stainless steel.

Fig. 2 shows the mixer grinder 1 in a section view. The jar 2 is equipped with a blade assembly 100 according to the first embodiment of the invention. An electric motor 11 is provided with a shaft 10 which is connected to a coupler 9. To the other (upper) portion of the coupler 9 a shaft or a spindle 8 of the blade assembly 100 is threadedly attached. The spindle 8 has a bottom part coupled to the electric motor 11 and an upper part coupled to the blade assembly 100. The torque flows from the electric motor 11 or its shaft 10 to the coupler 9 and therefrom to the blade assembly 100 or its spindle 8. A fan 12 is positioned above the electric motor 11 to ventilate the interior of the mixer grinder 1.

Fig. 3 depicts the blade assembly 100 according to the first embodiment of the invention. The blade assembly 100 includes four blades 13. The blades 13 are arranged equidistant from each other and are preferably of the same shape. The blades 13 are mounted on the spindle 8 (shaft). The bottom part of the spindle 8 includes a thread for connection to the coupler 9. A cap 101 is positioned on the blades 13. A washer can be arranged between the cap 101 and the blades 13. The cap 101 comprises a pair of actuation means 102 (only one shown) situated in the upper region of the cap 101 (sideways). The actuation means 102 are preferebly formed as buttons to be pushed (pressed).

Fig. 4 shows the blade assembly 100 according to the first embodiment in a section view. A cavity 107 is formed in the interior of the cap 101 for receiving an engaging mechanism EM1. The engaging mechanism EM1 comprises a pair of levers 103 and a biasing means 104. The levers 103 are pivotable about an axis A. The axis A represents a centre line for a shaft to which the levers 103 are attached. The actuation means 102 is arranged on the upper portion of each of the levers 103, whereas a projection 106 is arranged on the lower portion of each of the levers 103. The levers 103 and the actuation means 102 thereof are opposed to each other. The biasing means 104 is preferably a spring.
The upper part of the spindle 8 includes two opposing holes 105, preferably formed as blind holes, configured to receive the projections 106 of the levers 103.

Upon pushing or pressing the actuation means 102 (buttons) the levers 103 pivot about the axis A against the force of the biasing means 104. At the same time the projections 106 of the levers 103 are removed from the holes 105. The cap 101 comprising the engaging mechanism EM1 can be detached from the spindle 8. Afterwards, the blades 13 can be removed from the spindle 8.

Fig. 5 depicts a blade assembly 200 according to the second embodiment of the invention. A cap 201 is arranged on the blades 13. A pair of actuation means 202 is provided on sides of the cap 201, preferably centrally, in a opposing manner. The blades 13 are arranged equidistant from each other and are preferably of the same shape. The actuation means 202 are preferebly formed as a button to be pulled.

Fig. 6 shows the blade assembly 200 according to the second embodiment in a section view. The interior of the cap 201 accommodates a cavity 207 for receiving an engaging mechanism EM2. The engaging mechanism EM2 is constituted of a pair of rods 203 and a pair of biasing means 204. The actuation means 202 is arranged on the outer portion of each of the rods 203. The inner portions of the rods 203 form projections 206. The projections 206 are received in the corresponding holes 205 of the spindle 8. The two holes 205 are preferably formed as blind holes. The rods 203, the actuation means 202 thereof and the biasing means 204 are opposed to each other. The biasing means 204 is preferably a spring.

Upon pulling the actuation means 202 (buttons) the rods 203, more specifically its projections 206, are removed from the holes 205 in the upper part of the spindle 8. The action of pulling is executed against the force of each of the biasing means 204. The cap 201 comprising the engaging mechanism EM2 can be detached from the spindle 8. Then the blades 13 can be removed from the spindle 8.

Reference signs list

1 mixer grinder
2 jar
3 lid
4 handle
5 base appliance
6 knob
7 suction feet
8 spindle (shaft)
9 coupler
10 shaft (electric motor)
11 electric motor
12 fan
13 blade

100, 200 blade assembly
101, 201 cap
102, 202 actuation means
103 lever
104, 204 biasing means
105, 205 hole
106, 206 projection
107, 207 cavity
203 rod

A axis
EM1, EM2 engaging mechanism
R recess