FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A modular mixer grinder
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company


INVENTORS
Sivadas Alakkal Kizhakkethil and Lohokare Yogesh, both of Crompton Greaves Limited, AMDTC, CG Global R&D Centre, Kanjurmarg (East), Mumbai 400042, Maharashtra, India, both Indian Nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:


FIELD OF THE INVENTION
This invention relates to a modular mixer grinder.
BACKGROUND OF THE INVENTION
A household mixer grinder, especially a mixer grinder used for grinding or mixing food articles comprises an electric motor housed within a moulded plastics body. The moulded plastics body generally comprises a base portion and a vertical portion. The base portion is provided with legs and air inlet holes at the bottom thereof. The vertical portion comprises a socket or collar at the top thereof adapted to locate a grinding jar. The electric motor comprises a pair of coaxially oppositely extending shaft-ends, one shaft end extending downwardly and the other shaft end extending upwardly into the socket at the top of the vertical portion. An axial fan is mounted on the said one shaft-end or a radial fan is mounted on the said other shaft-end and positioned within the vertical portion below the bottom of the socket formed at the top of the vertical portion. During operation of the mixer grinder, the axial fan or radial fan rotates with the respective shaft and sucks in air through the air inlet holes at the bottom of the base portion and draws the cooling air over the motor to keep the motor cooled. In order to reduce noise
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level of the mixer grinder and guide the cooling air onto the electric motor, an air guiding and noise dampening sleeve is known to be provided over the electric motor. The upper end of the air guiding and noise dampening sleeve is fitted with a perforated disc so as to interrupt the air flow and further reduce the noise level. The lower end of the air guiding and noise dampening sleeve is usually at a distance from the bottom of the base portion. The air inlet holes are also offset and away from the lower end of the air guiding and noise dampening sleeve. As a result, air being sucked in by the fan has to take a turn and travel a distance in the base portion before entering the air guiding and noise dampening sleeve. Because of this and because of the expansive area within the base portion, there is pressure drop. Due to the pressure drop, the cooling efficiency of the fan is reduced. In order to increase the cooling efficiency of the fan, the fan size is required to be increased. Fan size increase correspondingly increases the size of the fan and power consumption of the fan.
US 3901484 describes an electric food blender comprising an upright vessel having rotatable mixing and cutting blades mounted in the bottom thereof, a power unit having a housing enclosing an electric motor and means on said housing for supporting said vessel. The motor includes a stator and an
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armature having commutator brushes engaging the lower end thereof. The armature has a shaft which is supported for rotation about a vertical axis and which is with said blades. The housing is formed by a cup shaped main housing member having sidewalls, a top wall and an open bottom. The stator is mounted on the underside of said top wall. Armature bearings for said armature shaft are carried by bearing supports secured to said stator. A fan is mounted on the lower end of said armature shaft. A base housing member is secured to said main housing member to close said open bottom forming an enclosure for said motor. The base housing member is molded plastic having air inlet means through which motor cooling air is drawn in by said fan. An upstanding cylindrical flange is formed integral with said base housing member and surrounding said air inlet means. The upstanding flange extends upwardly around the lower end of said armature enclosing said commutator brushes. The top edge of said flange is in close proximity with said stator to direct said motor cooling air across said armature and said stator. Air discharge openings are provided in said main housing member to exhaust said motor cooling air. Since the air guiding upstanding flange extends only up to the lower end of the armature of the motor, there is no further guiding of air onto the electric motor. There is also no regulation of the cooling air flowing out of the blender body. There is also no dampening of the noise level. As a
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result of all this, there is pressure drop and insufficient cooling of the motor and increase in the noise level. Due to pressure drop, cooling efficiency of the fan is reduced. Increase in size of the fan increases the cost of the fan and also power consumption by the fan. The food blender also comprises a large number of components correspondingly increasing the cost.
US 7320542B2 describes a blender comprising a base frame including a hollow column in a central portion thereof defining a compartment and a perimeter wall surrounding the hollow column defining a space between the perimeter wall and the hollow column. The hollow column includes an opening in a bottom end thereof. The perimeter wall includes two opposite sides each having a plurality of slots. Each of said opposite sides includes a recessed portion for guiding air out of the base frame. The separating plates extend downward from the bottom end of the base frame and face the opposite sides, respectively. A notch is defined in the perimeter wall and not aligned with the slots. An air-guiding groove is provided between the notch and the opening. A cover is provided for covering the base frame. A muffler housing is mounted to the bottom end of the base frame and includes a plurality of apertures communicated with the opening of the base frame for guiding air. A motor is received in the compartment of the hollow column, the motor
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including an upper drive shaft adapted to drive a mixing blade means and a lower drive shaft. A fan is driven by the lower drive shaft for driving ambient cool air into the compartment of the hollow column via the notch, the air-guiding groove and the apertures thereby directly cooling the motor with hot air exiting the blender after passing through the compartment, the space, the slots and the recessed portions of the base frame and with the separating plates preventing the hot air from entering the blender. The cooling air flows up over the fan and then takes a U-turn and flows down and out of the blender. Therefore, the air flow path is very long creating pressure drop and reducing the cooling efficiency of the fan. In order to increase the cooling efficiency of the fan, the fan size will have to be increased. This will increase cost of the fan and power consumption by the fan. As the air flow is not regulated, the noise level of the blender during operation is high. The blender also comprises a large number of components correspondingly increasing the cost.
OBJECTS OF THE INVENTION
An object of the invention is to provide a modular mixer grinder, which is simple in construction and easy and convenient to assemble and which can be assembled within reduced time.
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Another object of the invention is to provide a modular mixer grinder which has increased cooling efficiency and reduced noise level.
Another object of the invention is to provide a modular mixer grinder which reduces power consumption and cost.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a modular mixer grinder comprising a moulded plastics body comprising a base portion having legs at the bottom surface thereof and an upstanding collar at the upper surface thereof and a plurality of air inlet holes within the space defined by the collar, a middle portion fitted onto the base portion and having a vertical portion comprising an inwardly extending mounting flange at the top thereof, an inverted cupshaped top portion located at the upper end of the vertical portion and fitted onto the inwardly extending mounting flange and comprising a plurality of slots at the bottom edge thereof and further comprising a socket formed at the center thereof adapted to locate a grinding jar, an electric motor vertically disposed in the vertical portion and comprising a perforated casing and a plurality of spaced laterally extending
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projections and a pair of coaxially oppositely extending shaft-ends, one shaft end extending downwardly and fitted with an axial fan and the other shaft end extending upwardly into the socket, the electric motor being mounted on the inwardly extending mounting flange with the laterally extending projections of the motor fitted on the inwardly extending mounting flange, an air guiding and noise dampening sleeve disposed over the electric motor and located against the bottom of the base portion within the collar at the upper surface thereof and against the inwardly extending mounting flange and an air flow regulating and noise dampening cover comprising an inverted hollow spherical member provided with an open top, the semispherical member being disposed over the top of the electric motor and located on the inwardly extending mounting flange with the socket wall extending into the spherical member through the open top thereof, the spherical member having a plurality of openings therethrough.
The following is a detailed description of the invention with reference to the
accompanying drawings, in which :
Fig 1 is an elevation of a modular mixer grinder according to an embodiment of the invention;
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Fig 2 is a crosssectional view, of the mixer grinder of Fig 1;
Fig 3 is an isometric view of the air guiding and noise dampening sleeve of the mixer grinder of Fig 1;
Figs 4 and 5 are top and bottom isometric views of the air flow regulating and noise dampening cover of the mixer grinder of Fig 1;
Fig 6 is an isometric view of the top portion of the mixer grinder of Fig 1; and
Fig 7 is a top view of the electric motor of the mixer grinder of Fig 1.
The modular mixer grinder 1 as illustrated in Figs 1 to 7 of the accompanying drawings comprises a base portion 2 provided with legs 3 at the bottom surface thereof 4 is an upstanding collar provided at the upper surface of the base portion. A plurality of air inlet holes 5 are provided in the base portion within the area defined by the collar. 6 is a middle portion fitted onto the base portion with screws 7 and having a vertical portion 8. 9 is an
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inwardly extending mounting flange extending from the upper end of the vertical portion. 10 is an inverted cupshaped top portion located at the upper end of the vertical portion and fitted to the inwardly extending mounting flange 9 by screws 11. The top portion comprises a plurality of slots 12 at the bottom edge thereof and further comprises a socket or collar 13 formed at the center thereof adapted to locate a grinding jar (not shown). 14 is a vertically disposed electric motor comprising a perforated casing 15 and a plurality of spaced laterally extending projections 16 and a pair of coaxially oppositely extending shaft-ends 17,18. The motor is mounted onto the inwardly extending mounting flange 9 by supporting the projections 16 against the flange 9 and fitting the projections 16 onto the flange 9 by screws 19. 20 is a spacer. Shaft-end 17 extending downwardly is fitted with an axial fan 21. Shaft-end 18 extending upwardly protrudes into the socket. 22 is an air guiding and noise dampening sleeve which is flared in construction. The lower end of the sleeve marked 22a is narrow and is located in the area of air inlet holes 5 at the upper surface of the base portion against the collar 4. The upper portion of the sleeve marked 22b is flared and is located against the inwardly extending mounting flange. 23 is an air flow regulating and noise dampening cover comprising an inverted hollow spherical member provided with an open top marked 23a. The inverted hollow spherical
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member is disposed over the top of the electric motor and located against the inwardly extending mounting flange with the socket extending into the spherical member through the open top thereof. The spherical member is provided with a plurality of openings 23 b therein.
During operation of the mixer grinder atmospheric air is directly sucked into the air guiding and noise dampening sleeve 22 through the air inlet holes 5 in the base portion 2. The fan draws the cooling air over the electric motor into the spherical member 23. Air in the spherical member flows out into the space between the spherical member and the top portion 10 and escapes into the atmosphere via the slots 12 at the bottom edge of the top portion. The air guiding and noise dampening sleeve directs and guides the cooling air onto the electric motor so as to cool the motor effectively and efficiently. The sleeve also helps to dampen the noise created by air cutting by the fan. The flared construction of the sleeve accelerates the cooling air velocity within the sleeve so as to improve the cooling efficiency. The air entering the spherical member 23 helps to cool the top portion of the electric motor. The air flowing out of the spherical member is regulated by the openings 23b therein. The spherical member also helps to dampen and reduce the noise level. As a result of all this, the entire motor is effectively cooled and the
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cooling efficiency of the mixer grinder is improved and noise level is reduced. The fan size can be reduced without compromising the cooling efficiency so as to reduce cost and power consumption by the fan. The mixer grinder can be easily assembled by first assembling the electric motor with the fan onto the inwardly extending mounting flange 9 of the vertical portion 8. Following this, the spherical member is located over the inwardly extending mounting flange and the top portion 10 is assembled and screw fitted onto the inwardly extending mounting flange. The base portion 2 with the sleeve 22 located thereon is screw fitted onto the middle portion 6 to fully assembly the mixer grinder. Therefore, the entire assembly of the mixer grinder is very simple and can be carried out easily within reduced time. The mixer grinder also comprises fewer components and is further cost effective.
The above embodiment is by way of example and should not be construed and understood to be limitative of the scope of the invention. Embodiments comprising variations of the invention like snap or bolt fitting the base portion, middle portion and top portion of the moulded plastics body instead of screw fitting, which are obvious to those skilled in the art, are to be construed and understood to be within the scope of the invention.
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We claim :
1) A modular mixer grinder comprising a moulded plastics body comprising a base portion having legs at the bottom surface thereof and an upstanding collar at the upper surface thereof and a plurality of air inlet holes within the space defined by the collar, a middle portion fitted onto the base portion and having a vertical portion comprising an inwardly extending mounting flange at the top thereof, an inverted cupshaped top portion located at the upper end of the vertical portion and fitted onto the inwardly extending mounting flange and comprising a plurality of slots at the bottom edge thereof and further comprising a socket formed at the center thereof adapted to locate a grinding jar, an electric motor vertically disposed in the vertical portion and comprising a perforated casing and a plurality of spaced laterally extending projections and a pair of coaxially oppositely extending shaft ends, one shaft end extending downwardly and fitted with an axial fan and the other shaft end extending upwardly into the socket, the electric motor being mounted on the inwardly extending mounting flange with the laterally extending projections of the motor fitted on the inwardly extending mounting flange, an air guiding and noise dampening sleeve disposed over the electric motor and located against the bottom of the base portion within
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the collar at the upper surface thereof and against the inwardly extending mounting flange and an air flow regulating and noise dampening cover comprising an inverted hollow spherical member provided with an open top, the semispherical member being disposed over the top of the electric motor and located on the inwardly extending mounting flange with the socket wall extending into the spherical member through the open top thereof, the spherical member having a plurality of openings therethrough.
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2) The mixer grinder as claimed in claim 1, wherein the air guide and noise dampening sleeve is flared and comprises a narrow lower portion and a wide upper portion.