Claims:
1. An automatic mixer grinder, comprising:
a base plate including main body housing;
a DC motor including an external power supply; and
a control board including a micro controller and with three sets of connection sockets for motor to controller connection, external power supply and protection fuse to controller connection; wherein the micro controller is configured for controlling the switching (on / off), speed and duration cycle of the DC motor.

2. The mixer grinder as claimed in claim 1, wherein the main body includes single or two parts including top cover.

3. The mixer grinder as claimed in claim 1, wherein the base plate further includes protection relay and protection fuse.

4. The mixer grinder as claimed in claim 1, wherein the main body includes a front plate to accommodate press buttons connected with control board.

5. The mixer grinder as claimed in claim 1, wherein the controller board (PCB) includes sections for:
a) Power supply section comprising bridge rectifier and regulator;
b) Input interface of selector switches & LED indicators;
c) Micro controller; and
d) Switching devices connecting to the motor.

6. The mixer grinder as claimed in claim 1, wherein the micro controller is programmed for controlling the DC motor for a pre set / particular menu.

7. The mixer grinder as claimed in claim 1, wherein the DC motor does not include any multiple tap winding and the speed control is achieved by means of PWM control only.

8. The mixer grinder as claimed in claim 1, wherein the said unit is configured to stop automatically once the preset operation is complete and no stir of the contents in the jar is required.

9. The mixer grinder as claimed in claim 1, wherein the said unit further includes jars with cutting blades attached to them and is connected with the said DC motor by means of coupler.

10. The mixer grinder as claimed in claim 1, wherein the said control board is further configured to allow the execution of said menu functions on retrofit and can be operated remotely.

11. The mixer grinder as claimed in Claim 1, where in the jars is self locking and hands free.
, Description:FIELD OF INVENTION
The present invention generally relates to automatic mixer grinder. More particularly, the present invention relates to a micro controller based programmable mixer grinder equipped with a multiple present menus, to provide consistent output of grinding and mixing of ingredients.

BACKGROUND ART
A mixer grinder is an electro-mechanical device which helps user to do mixing, grinding, juicing etc with ease. There is always an electric motor housed in a suitable enclosure with a provision to attach a mixing jar with appropriate cutting blades. Generally multiple speed options and safety devices for electric safety, over- current/temperature safety etc are provided with the mixer grinder.

A variety of mixer grinders for domestic and commercial use are available, including independent units or combined units for dry mixing, wet mixing, juicing, blending etc. Majority of mixer grinder’s available use an electromechanical rotary switch to control the speed of operation, which is directly, related the grinding/mixing performance. It is known in existing mixers to provide multiple speed settings for the mixers. The various available mixing speeds are primarily driven by a motor through combinations of gears and/or belts and/or variable adjustable pulleys, where mechanical adjustments are made to change mix speeds. Such mixer / grinder require that the mixer be stopped in order to change speeds.

User is required to select the right speed setting ie, Low/medium or High depending on the need. Regular intervention of user is required to open the jar lid, check the grinding / mixing level of food stuff, stir occasionally, close the lid and re-start the mixer. There is no guide lines available for mixing operations but is carried out by trial and error and on-job experience.

To solve this problem, an Indian specification 04664/CHE/2014 discloses a method and a control circuit for controlling a grinder. The control circuit comprises a mode select unit to select a mode of operation of the grinder, a timer unit comprising a down timer for selecting a time duration for which the grinder operates, a speed control unit to select an operating speed of the grinder and a control unit to operate grinder by activating a motor based on inputs received from at least one of the mode select unit, timer and speed control unit, the control unit performs one of operating the motor after the time duration set by up-timer or directly operating the motor for a time duration set up by up-timer. The disclosed grinder has lacunae wherein user can select the required speed and time of operation but it is necessary to know the requirement in terms of speed and time of operation for each grinding/mixing operation.

In another prior art, a PCT application WO2004103128A2 discloses an automatic cooking and material handling system to automate the cooking operation. The said system cooks all kind of possible dishes of any type, composition and shape. The only requirement for the users would be to bring food items from the market and load it to ACS and they have to choose or instruct which food they want to get cooked. The system makes it possible to get the required dish, amount and quality. It also makes it possible to change the composition of the cooked food for the required content, taste and quality. Also it allows multiple dishes to be cooked at the same time. The user can instruct ACS remotely through a communication link and the food will be cooked ready at the specified time. With respect to the present invention, the said system is very expensive with complex control and electro-mechanical handling system is not suitable for mixer grinders.

In another prior art, an US specification US3612969A discloses an automatic blending solution for blenders for food preparation. It discloses an automatic blender that can be programmed to perform a variety of tasks with perforated recipe card. The card bearing the desired recipe is inserted between a printed circuit control board and an assembly of spring brushes so that the perforations allow only selected brushes to make electrical contact with the PCB. The blender START push button and power switch are also actuated by the recipe card, so the blender has no external controls. The disclosure explains a digital card with recopies which can be inserted into the blender. This has limited use particularly in blending and cannot support other dry grinding, wet grinding etc. Moreover this is more expensive due the need of digital card reader and related electronic control methods. This also requires additional brushes to make electrical contact with the printed circuit board. This can affect the reliability of the blender in long run.

OBJECT OF INVENTION

It is the general object of the present invention to overcome the above mentioned disadvantages.

As per the principle object of the present invention, there is provided a micro controller based programmable mixer grinder equipped with a multiple present menus, to provide consistent output of grinding and mixing of ingredients.

Another object of this invention is to provide the user a mixer grinder which can run and stop once the food processing is completed.

Another object of this is to provide the user a mixer grinder which can operate without any intervention by the user.

Another object this invention is to provide a mixer grinder configured with a safe “hands free” operation.

Another object of this invention is to provide a mixer grinder configured with various menus of user choice.

Another object of this invention is to provide a mixer grinder configured to de-skill the user from the operating procedures for various menus.

Another object of this is to provide a more user friendly control.

Another object of this is to provide the user with a device to carry out and conclude the selected operation there by providing an opportunity to multi task.

SUMMARY OF THE INVENTION
In one aspect, a mixer grinder unit includes a motor and motor control electronic circuit board with an interface of buttons and LEDs to allow selection and start and stop by user. Electronic Control board comprises of a micro controller based control, integrated with mixer Grinder apparatus for automatically preparing the desired level of grinding and mixing of ingredients. This mixer is equipped with multiple preset menus, to provide consistent output of grinding and mixing of ingredients.

Therefore such as herein described there is provided an automatic mixer grinder, comprising a base plate including main body housing; a DC motor including an external power supply; and a control board including a micro controller and with three sets of connection sockets for motor to controller connection, external power supply and protection fuse to controller connection; wherein the micro controller is configured for controlling the switching (on / off), speed and duration cycle of the DC motor.

In another aspect of the present invention the mixer grinder unit also includes an optional key pad interface with at least one input mechanism and a control system which receives input from the user interface and is connected for controlling operation of the drive motor to provide control of motor speed and duration to effect mixing / grinding operations by changing PWM duty cycle and time duration through programming.

In a further aspect of the present invention, the control system is configured for a retrofit to a prior art mixer grinder unit and thereafter configured for controlling the switching (on / off), speed and duration cycle of the DC motor in order to customize the operation of the said unit.

In yet another aspect, a DC motor of the said mixer grinder unit is controlled through PWM (Pulse Width Modulation) control and therefore additional tap winding for obtaining variable speed and associated connection problems are eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a Schematic Diagram of the mixer grinder in accordance with the present invention;

FIG. 2 illustrates an exploded view of mixer grinder in accordance with the present invention;

FIG. 3 illustrates a Mixer Grinder assembly in accordance with the present invention;

FIG. 4 illustrates front plate with LED locations for the Mixer Grinder assembly of FIG. 3;

FIG. 5 illustrates the Poka Yoke for error free assembly for the Mixer Grinder assembly of FIG. 3;

Fig 6 illustrates Printed circuit board assembly on the body for the Mixer Grinder assembly of FIG. 3;

Fig 7 illustrates connections for current motor with tapped winding in accordance with the present invention;

Fig. 8 illustrates connections for current motor with control board in accordance with the present invention;

Fig.9 illustrates a block diagram of controller in accordance with the present invention;

Fig. 10 illustrates Speed Vs Time graph for few menus in accordance with the present invention;

DESCRIPTION OF DISCLOSURE
An automatic mixer grinder apparatus is described herein to make up for the deficiencies of the prior art, provides a highly efficient energy-saving, programmable automatic mixer grinder. The present invention is achieved through the following description.

Referring to FIGS. 1–3, a mixer grinder unit is shown and includes a base, a mixer body (housing). The mixer grinder unit further comprises of Jar, fitted with rotary blade mounted on vertical shaft connected with coupler to a driving motor. Mixing jar is coupled to a motor shaft, when the jar is placed in the position using a coupler. The motor is controlled with an electronic circuit having microcontroller based program. The program controls the drive with variable speed according to program selection using with Pulse width Modulation technique. The motor operates at different speed for a selected time period depending on the menu selected. Each preset menu comprises of the combinations of these Rotary speed and time which delivers the desired level of grinding texture for the food item.

The exploded view of the disclosed mixer grinder unit as shown in Fig 2 illustrates major hardware components including Mixer base, PCB, PCB mounting bracket, Facia Plate / Sticker, main body (housing), top cover, coupler, motor, suction pads, fuse / fuse holder and overload protector. The PCB includes a microprocessor and dedicated proprietary circuitry for desired control of the mixer grinder unit. The microcontroller is configured for further programming and control of the motor. The control of the motor using different programs and set up menu in accordance with the need of the user menu will be explained in detail in forthcoming description.

Having a preset menu eliminates the need of manual intervention/ checking of the grinding quality at intervals. It also eliminates the human error and achieves required grinding performance as per menu selected by user. It also serves customised control by user by selecting manual mode operation.

In the prior art, and as shown in Fig 7, the market available mixer grinders use a motor with tapped winding for speed variation. These tap connections are taken to a rotary switch and the required speed selection is achieved by rotating the switch to the required tap. Here multiple wires from motor winding are to be taken out and connected to the switch. This is time consuming and proper bunching of wires and routing requires additional effort during assembly process. On the contrary, and as shown in Fig 8, the disclosed invention includes a motor wherein multiple tap winding is not required. Speed control is achieved by means of PWM control there by need of motor with additional tap winding and associated connection problems are eliminated.

There are no loose wiring and interconnections required. Two wires from motor are just required to be connected to the electronic controller board. External power connection is to be made to the controller. Therefore electrical wiring and wire routing is simpler and non-complicating.

This invention also provides an opportunity to convert a manual mixer grinder to an automatic mixer grinder by a retrofit of control PCB as shown in Fig 6 i.e. connecting the control board to the motor wires and using the push buttons instead of rotary switch. User has to remove the rotary switch. Push buttons on the control board is laid out to suit the switch slot on the body. Hence the user needs to mount the control board in the housing in such a way that the push buttons on the board gets aligned in the switch slot. This provides an economic upgrade of the manual mixer grinder to an automatic mixer grinder.

Mixer grinder consists of the following
1. a fractional horse power motor as shown in Fig 2.
2. control board with three sets of connection sockets for
a. motor to controller connection
b. external power supply
c. protection fuse to controller connection as shown in Fig 2.
3. main body which is in single or two parts including top cover as shown in Fig 1 and 2.
4. a base plate with protection relay and protection fuse mounted on it as shown in Fig 2.
5. a front plate to accommodate press buttons as shown in Fig 4 and 5.
6. a set of LEDs mounted on the control board for visual indication as shown in Fig 5.
7. an external power cord for connecting to electric power (not shown).
8. a set of self locking and hands free jars with cutting blades attached to each of them as shown in Fig 1.

Controller PCB is attached to the body by means of a bracket or directly on the body. Controller is fixed in such a way that indicating LEDs are facing front. Two slots are provided on control board which will get aligned with two corresponding ribs on the body for proper alignment. This will also help an easy and error free assembly by a semi-skilled person during assembly process. The LEDs are also positioned to occupy the slots provided on the front plate. A sticker with graphics to indicate the switches is pasted on the front plate. Similar poka yoke is also provided on the sticker and its mating part by way of a tiny rib and corresponding cut out on the sticker for ease and error free assembly.

The Controller printed circuit board has the following major sections as shown in Fig 9:
1. Power supply section comprising bridge rectifier and regulator
2. Input interface of selector switches & LED indicators
3. Micro controller
4. Switching devices connecting to the motor
5. Provision for micro controller programming

The input power source is electrically coupled to the Controller using electronic interconnectors, such as a printed circuit, metal foils, wires, tabs or electrically conductive adhesives. When connector is in a connected state, the power source, delivers power to the motor through Controller of the control board circuitry of PCB. In an alternative arrangement, the controller further comprise a transceiver operable and remotely controlled from a distance via a remote, which is also comprising of a transceiver / receiver for the communication with the said controller configured for an improved and efficient use of the mixer grinder unit such as herein described. A person skilled in the art can appreciate the implication of such transceivers in the mixer grinder unit, which makes the system versatile irrespective of any physical constraints. Under such condition additional circuitry is also accommodated in the said control board PCB of Fig 6.

When the mixer is switched ON, a glowing LED will indicate the curser position. User can select the constant speed manual option or pre set menu. To change the selection clock wise or anticlockwise keys are provided. When the power ON switch is pressed, mixer grinder will start operation. The user need to just keep the required jar based on the amount of content and type of grinding or mixing, rotate the jar to lock and close the lid. Lid is provided with a rotate and lock feature for safety.

In an exemplary embodiment, the user does not have to hold the lid on the jar. Mixer will stop automatically once the preset operation is complete. It is not required to stir the contents in the jar occasionally by the user. Flow breakers provided along with the grinding cycle that is speed variation, on/off cycle and duration will ensure the uniform grinding/mixing. Total cycle time for each menu is set based on the research. Therefore the disclosed mixer grinder unit avoids the need of continuous intervention by the user. Safety is ensured by lock jars. Frequent opening of jar lid and manual stirring is not required.

In another embodiment the disclosed mixer grinder unit is provided with protection for over current, additional fuse to protect the electronic PCB and safety lock on jars. All this provides the user with a superior grinding experience.

In another embodiment the mixer grinder unit also includes an optional key pad interface (not shown) with at least one input mechanism and a control system which receives input from the user interface and is connected for controlling operation of the drive motor to provide control of motor speed and duration to effect mixing / grinding operations by changing PWM duty cycle and time duration through programming of the micro processor as per the desire of the user. The programming is limited over the threshold values of the set parameters of the motor and other PCB components and is known to a person skilled in the art.

Below mentioned table are the pre set menus arrived at after a long research on grinding operations. The speed, duration & speed variation for each operation is arrived at by research. This parameter for each menu is different. Speed variation is achieved by pulse width modulation and varying duty cycle. Entire logic is embedded in the microcontroller. A Speed Vs Time graph for few menus as shown in Fig 10 for reference.

When the user selects a menu by selection and pressing of respective push button, mixing operation that is the speed and duration is achieved as below. Programme is set to achieve the required duty cycle and time duration.

Menu Program set for
1 Manual speed 1 Speed 16000 RPM by PWM with 0.88 duty cycle
Duty cycle=((Ton/(Ton+Toff))
2 Manual speed 2 Speed 17000 RPM by PWM with 0.9 duty cycle
3 Manual speed 3 Speed 18000 RPM by PWM with 1.0 duty cycle
4 Ice crushing Varying PWM for 95 Sec /cycle
5 Dhaniya 95 Sec with duty cycle 1.0 /cycle
6 Turmeric Varying PWM for 185 Sec /cycle
7 Juice/Lassi Varying PWM for 35 Sec /cycle
8 Chutney 50 Sec with duty cycle 0.9 /cycle
9 Udad Dal Varying PWM for 185 Sec / cycle
10 Rice 305 Sec with duty cycle 1.0
11 Sambar Masala 95 Sec with duty cycle 1.0
12 Wet Masala 95 Sec with duty cycle 0.88 / cycle

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.