DESC:FIELD OF THE INVENTION
[001] The present invention relates to a mixer grinder.

BACKGROUND OF THE INVENTION
[002] Mixer grinders are widely used for grinding, blending and dicing food products. The mixer grinders typically include a base unit with motor which drives blades provided in a jar. Mixer grinders incorporate vents on housing of the base unit to facilitate the passage of air out of the mixer grinder body. While the vents serve the purpose of cooling the motor and preventing overheating, they also give rise to a series of issues that undermine user satisfaction, safety, and longevity of the mixer grinder.
[003] The presence of motor and vents in current mixer grinder designs leads to elevated noise levels during operation. This noise can be bothersome and disruptive in a household setting, affecting the overall experience and comfort of the user. Additionally, these vents permit the entry of various contaminants, including dust, insects, food spillage and humidity into the mixer grinder unit. This poses hygiene and sanitation concerns and leads to equipment malfunction, damage and reduced operational lifespan of the mixer grinder.
[004] Moreover, the conventional vents in the mixer grinder unit discharge hot air from the motor. In certain instances, this hot air blast poses a risk of burns to the user, especially if they inadvertently come into contact with the vents during operation.
[005] Thus, there is a need in the art for a mixer grinder, which addresses at-least the aforementioned problems.
SUMMARY OF THE INVENTION
[006] In one aspect, the present invention provides a mixer grinder. The mixer grinder includes a base unit, a motor and a fan unit. The base unit includes a ventless housing. The ventless housing includes a bottom cover, a top cover opposing the bottom cover and a peripheral wall extending between the bottom cover and the top cover. The motor disposed within the ventless housing spaced apart from the top cover of the base unit. The motor has a plurality of vents on each of a top surface and a bottom surface of the motor. The motor has a motor shaft extending from a top end to a bottom end. The top end of the motor shaft being configured to receive a coupler. The fan unit is positioned below the motor. The fan unit includes a fan coupled to the bottom end of the motor shaft. The motor and the fan unit are positioned spaced apart from an inner side of the peripheral wall and the bottom cover of the ventless housing to allow circulation of air around the motor during operation of the mixer grinder.
[007] In an embodiment, the bottom cover is configured to receive a Printed Circuit Board (PCB).
[008] In an embodiment, the fan unit includes the fan housed in an enclosure. The enclosure includes an outer wall and a bottom plate. The bottom plate includes a plurality of openings. The plurality of openings face a plurality of blades of the fan and configured to direct the airflow towards the bottom cover of the ventless housing.
[009] In an embodiment, the plurality of openings of the bottom plate extends beyond an outer edge of the plurality of blades of the fan such that an overall diameter of the circumferentially spaced openings is greater than a diameter of the fan.
[010] In an embodiment, the motor is a Brushless Direct Current (BLDC) motor.
[011] In an embodiment, the fan unit positioned spaced apart from an inner side of the peripheral wall and the bottom cover of the ventless housing to form one or more air passages. The fan pulls air from the bottom surface of the motor and directs the air towards the bottom cover and circulates the air through the air passages around the motor during operation of the mixer grinder.

BRIEF DESCRIPTION OF THE DRAWINGS
[012] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows a mixer grinder in accordance with an embodiment of the invention.
Figure 2 which shows a sectional view of a housing of a base unit in accordance with an embodiment of the invention.
Figure 3A shows an assembled view of the motor and a fan unit in accordance with an embodiment of the invention.
Figure 3B shows an exploded view of the motor and the fan unit in accordance with an embodiment of the invention.
Figure 3C shows an enclosure of the fan unit in accordance with an embodiment of the invention.
Figure 4 shows a bottom view of the motor in accordance with an embodiment of the invention.
Figure 5A and Figure 5B show an illustrative representation of air-flow within the base unit of the mixer grinder in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[013] The present invention is directed towards a mixer grinder whereby a base unit of the mixer grinder has a ventless body/housing. The base unit is provided with a motor and a fan unit positioned below the motor and an air passageway formed within the base unit which results in an airflow within the base unit thereby cooling the components, especially motor housed within the base unit.
[014] Figure 1 shows a mixer grinder 100 in accordance with an embodiment of the invention. The mixer grinder 100 comprises a jar 400 and a base unit 200. The base unit 200 is configured to support the jar 400. The jar 400 receives foodstuff/ingredients/materials for blending/grinding/chopping and can vary in shape and size as per requirement. Typically, the jar 400 comprises of one or more blades configured to perform blending/grinding/chopping functions, and a lid to cover the jar 400. Further, the jar 400 is configured to be adapted to the base unit 200, whereby the blades of the jar 400 interconnect with a coupler 102 of the base unit 200 (shown in Figure 1).
[015] Referring to figure 2 which shows a sectional view of a housing 110 of the base unit 200. The base unit 200 has the housing 110. In an embodiment, the housing 110 is a ventless housing. The ventless housing 110 comprises of a bottom cover 116, a top cover 126 opposing the bottom cover 116 and a peripheral wall 130 extending between the bottom cover 116 and the top cover 126. The housing 110 may be of any shape, size or configuration, such as rectangular, including square-shaped, or cylindrical as per requirement. The shape, size and configuration of top cover 126, the bottom cover 116 and the peripheral wall 130 thus can be varied as per requirement. In a non-limiting example, the base unit 200 including the housing 110, is made of Acrylonitrile Butadiene Styrene (ABS). ABS used for the base unit 200 provides impact resistance, heat stability, chemical durability, ease of manufacturing, electrical insulation properties, cost-effectiveness and aesthetic flexibility. Further, one or more feet 124 are disposed on a bottom surface of the bottom cover 116 to engage a surface such as a countertop to support the base unit 200.
[016] Further, as shown in Figure 2, the housing 110 encloses a motor 104, a fan unit 300 and other components. As shown, the motor 104 is mounted adjacent to a top surface of the housing 110 such that the motor 104 is spaced apart from the top cover 126 of the housing 110. The motor 104 is mounted to the housing 110 via a plurality of fasteners such as rubber pads or any other connecting means known in the art.
[017] In an embodiment, the motor 104 is spaced apart from an inner side of the peripheral wall 130 of the housing 110. The motor 104 is a Brushless Direct Current (BLDC) motor. Alternatively, motor such as Permanent Magnet Direct Current (PMDC) motor, Universal motor, Induction motor, Axial flux motor or in-runner motor. The motor 104 has a motor shaft 128 extending from a top end to a bottom end. The top end of the motor shaft 128 extends through the top cover 126 and has the coupler 102 which is configured to be detachably coupled with the blade of the jar 400. Accordingly, when the jar 400 is coupled to the base unit 200 and the motor 104 is driven, the blades of the jar 400 rotate. The motor 104 includes a plurality of vents 132a,132b (shown in Figure 3B and Figure 4) on each of a top surface and a bottom surface of the motor 104. The plurality of vents 132a,132b are aligned with stator windings 140 and rotor core 142 of the motor 104 to allow for direct airflow over the stator windings 140, ensuring that the hot air generated by electrical resistance in the stator windings 140 is efficiently dissipated. In a non-limiting example, an outer enclosure of the motor 104 is made of aluminum. The aluminum is surface treated by a shot blasting process, to increase the surface area of the outer enclosure of the motor 104 for enhanced heat dissipation.
[018] In an embodiment, as shown in figure 3A and 3B, the fan unit 300 is mounted below the motor 104. The fan unit 300 is mounted to the motor 104 via a plurality of fasteners 312, such as a screw or any other connecting means known in the art as shown in Figure 3B.
[019] In an embodiment, the fan unit 300 is spaced apart from the bottom cover 116 and spaced apart from an inner side of the peripheral wall 130 to create a space therebetween forming air-paths P ( shown in Figure 5A) around the fan unit 300 and the motor 104. The air-paths P are also referred to as air passages or air pathways or air passageway. The fan unit 300 comprises a fan 302 housed in an enclosure 304. In a non-limiting example, the fan 302 and the enclosure 304 are made of nylon. Nylon used for the fan 302 and enclosure 304 provides strength, lightweight nature, heat and wear resistance, chemical durability and cost-effectiveness, thereby ensuring efficient, durable, and noise-free operation of the mixer grinder 100.
[020] The fan 302 is mounted at the bottom end of the motor shaft 128 below the plurality of vents 132b provided on the bottom surface of the motor 104. The fan 302 is a radial fan having a plurality of blades oriented to expel air. A longitudinal gap/ clearance C (shown in Figure 2) is provided between an outer edge of blades of the fan 302 and the enclosure 304 to maintain airflow and prevent air cutting noise. Additionally, a lateral gap/ clearance X’ (shown in Figure 2) is provided between a lower surface of blades of the fan 302 and the enclosure 304 to prevent air back pressure. In a non-limiting example, the clearance C is at least 1.5 mm and the clearance X’ is at least 7.5 mm. Accordingly, when the motor 104 is driven, the blades of the jar 400 (coupled with coupler 102), and the fan 302 rotate simultaneously i.e., the fan 302 will rotate as and when the mixer grinder 100 is operated. The fan 302 upon rotation will pull air from the motor 104. In this regard, as shown in figure 4, plurality of vents 132b are provided on the bottom surface of the motor 104 for expelling the air out from the motor 104. During the operation of the mixer grinder 100, the fan 302 draws/pulls air from the motor 104, the air exiting through the plurality of vents 132b provided on the bottom surface of the motor 104. This air is then circulated through the housing 110, allowing heat to dissipate, and cooler air re-enters the motor 104 through the plurality of vents 132a provided on the top surface of the motor 104. As a result, the air that re-enters the motor 104 is significantly cooler, helping to maintain optimal temperature of the motor 104 and improve overall cooling efficiency.
[021] The enclosure 304 is shown in figure 3A and figure 3C. The enclosure 304 has an outer wall 306 and a bottom plate 308. The bottom plate 308 has a plurality of openings 310. As shown, the openings 310 are circumferentially spaced apart openings. The openings 310 are aligned with blades of the fan 302 i.e., the plurality of openings 310 are facing the plurality of blades of the fan 302. To ensure smooth air flow, the opening 310 provided on the bottom plate 308 extends beyond an outer edge of the plurality of blades of the fan 302 such that an overall diameter of the circumferentially spaced openings 310 is greater than a diameter of the fan 302. The fan 302 when rotated pulls/sucks air from the motor 104 with the help of build negative pressure. The fan 302 expels the air out of the enclosure 304 towards the bottom cover 116, and the air reflects from the bottom cover 116, and the air circulates through the air pathways P inside the housing 110. The openings 310 thus helps in guiding draft of air through the air pathways P, and the air will travel through the air pathways P around the motor 104, thereby adequately cooling the motor 104 without the need for vents on housing 110. Additionally, the enclosure 304 helps to maintain airflow and prevent air cutting noise in the base unit 200.
[022] Further, as shown, a Printed Circuit Board (PCB) 112 is disposed on the bottom cover 116. The PCB 112 has electric components that controls various functions of the mixer grinder 100. The enclosure 304 circulates the air partially through the plurality of openings 310 to maintain ambient temperature inside the base unit 200. Further, the enclosure 304 also directs the air downwards towards the PCB 112 as shown in Figure 5A. In a non-limiting example, the PCB 112 includes, but not limited to an Insulated-Gate Bipolar Transistor (IGBT), microcontroller, buck converter, Direct Current (DC) bus capacitor and bridge rectifier. The components of the PCB 112 have a relatively lower temperature than the temperature of the air expelled from the motor 104 by the fan unit 300. Such an arrangement ensures that when the hot air from the motor 104 is directed towards the PCB 112, the heat from the air is transferred to the PCB 112 and subsequently circulated within the housing 110. This facilitates efficient heat dissipation within the housing 110, allowing cooler air to be re-circulated and drawn back into the motor 104 through the plurality of vents 132a provided on the top surface of the motor 104. In an embodiment, the clearance between the enclosure 304 and the nearest component of the PCB 112 is at least 4 mm. Such a construction of the enclosure 304 provides multiple air paths P within the housing 110 of the base unit 200 resulting in forced circulation of air throughout the interiors of the base unit 200, thereby helping in maintaining ambient temperature within the base unit 200 and cooling the components within the base unit 200.
[023] Further, as shown in figure 2, the base unit 200 further comprises a knob 120 mounted on the housing 110. The knob 120 is a user interface for controlling the functions of the mixer grinder 100. A user operates the mixer grinder 100 as required by rotating the knob 120. The knob 120 is coupled to a mechanical switch 118. The mechanical switch 118 is controlled by the knob 120 thereby allowing the user to select between different speed modes, including Slow/Coarse and Pulse, and to control the food processing. An Interface PCB 114 is provided within the housing 110 that has electronic components to control and display the functions of the mixer grinder 110. The interface PCB 114 includes features like jar locking sensor, fault detection indicators and LED interface for user convenience. A light guide 122 is provided on an outer surface of the peripheral wall 130 that includes a LED light for indicating whether the motor 104 is ON/OFF and the different speed modes of the mixer grinder 100.
[024] Figure 5A and Figure 5B show a cross-sectional view of the base unit 200 whereby illustrative representation of the air-flow within the base unit 200 of the mixer grinder 100 is shown in accordance with an embodiment of the invention. As indicated by arrows C’, the fan 302 pulls air from the bottom surface of the motor 104 disposed within the housing 110 and directs the air towards the bottom cover 116 and circulates the air through air path P around the motor 104 from all sides. This ensures that the air is effectively circulated by creating multiple air paths P inside the housing 110, preventing the accumulation of heat, maintaining a consistent air temperature and providing cooling to the motor 104. Thus, present invention maintains consistent air temperature throughout the mixer grinder by evenly distributing the heat.
[025] Advantageously, the present invention provides a ventless base unit for a mixer grinder which eliminates noise and provides an enhanced user experience with reduced disruption in a household setting. Further, the base unit of the present invention being ventless prevents the ingress of contaminants and also eliminates the risk of burns to the user from hot air discharge, thereby ensuring a hygienic and user-friendly experience. Further, the present invention results in a compact design and extended operational runtime compared to conventional vented models. This leads to enhanced product durability and overall usability of the mixer grinder. Moreover, the present invention also eliminates the need for any mesh components or any specific exhaust vents in the base unit of the mixer grinder.
[026] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.
,CLAIMS:We Claim:
1. A mixer grinder (100) comprising:
a base unit (200) having a ventless housing (110), the ventless housing (110) having a bottom cover (116), a top cover (126) opposing the bottom cover (116) and a peripheral wall (130) extending between the bottom cover (116) and the top cover (126);
a motor (104) disposed within the ventless housing (110) spaced apart from the top cover (126) of the base unit (200) and the motor (104) having plurality of vents (132a,132b) on each of a top surface and a bottom surface of the motor (104), the motor (104) having a motor shaft (128) extending from a top end to a bottom end, the top end of the motor shaft (128) being configured to receive a coupler (102); and
a fan unit (300) positioned below the motor (104), the fan unit having a fan (302) coupled to the bottom end of the motor shaft (128), the motor (104) and the fan unit (300) being positioned spaced apart from an inner side of the peripheral wall (130) and the bottom cover (116) of the ventless housing (110) to allow circulation of air around the motor (104) during operation of the mixer grinder (100).

2. The mixer grinder (100) as claimed in claim 1, wherein the bottom cover (116) being configured to receive a Printed Circuit Board (PCB) (112).

3. The mixer grinder (100) as claimed in claim 1, wherein the fan unit (300) comprises the fan (302) housed in an enclosure (304), the enclosure (304) having an outer wall (306) and a bottom plate (308), the bottom plate (308) having a plurality of openings (310), the plurality of openings (310) facing a plurality of blades of the fan (302) and configured to direct the airflow towards the bottom cover (116) of the ventless housing (110).

4. The mixer grinder (100) as claimed in claim 3, wherein the plurality of openings (310) of the bottom plate (308) extends beyond an outer edge of the plurality of blades of the fan (302) such that an overall diameter of the circumferentially spaced openings (310) is greater than a diameter of the fan (302).

5. The mixer grinder (100) as claimed in claim 1, wherein the motor (104) being a Brushless Direct Current (BLDC) motor.

6. The mixer grinder (100) as claimed in claim 1, wherein the fan unit (300) being positioned spaced apart from an inner side of the peripheral wall (130) and the bottom cover (116) of the ventless housing (110) to form one or more air passages (P), the fan (302) pulls air from the bottom surface of the motor (104) and directs the air towards the bottom cover (116) and circulates the air through the air passages (P) around the motor (104) during operation of the mixer grinder (100).

Dated this 10th day of November 2023
Atomberg Technologies Private Limited
By their Agent & Attorney

(Janaksinh Jhala)
of Khaitan & Co
Reg No IN/PA-2193