FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“A ROTARY SWITCH CONFIGURATION FOR A MIXER
GRINDER”
We, Bajaj Electricals Limited, an Indian National, of 45/47, Veer Nariman Road, Fort Mumbai- 400001, India.
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present disclosure relates to the field of mixer grinders. More particularly, the present disclosure relates to a rotary switch configuration for a mixer grinder.
BACKGROUND OF THE INVENTION
This section is intended to provide information relating to the field of the invention and thus any approach or functionality described below should not be assumed to be qualified as prior art merely by its inclusion in this section.
A variety of food processors are known in the food processor industry, for example, the food processor is known in the household, for grinding, mixing, and blending various food and/or edible ingredients. A mixer grinder includes a processing unit and a jar unit, wherein the jar unit carries food articles and may be connected to the processing unit, to perform processing of the food articles. The processing unit includes a motor assembly housed within a main housing, and a cutter assembly connected to a rotor of the motor assembly, such that the cutter assembly is driven by the motor assembly for performing processing operations thereof. Conventionally, the motor assembly is operated through a rotary switch deployed on the main housing.
A typical rotary switch arrangement deployed in the mixer grinder comprises a rotatable shaft having a first end and a second end, a gear member having a plurality of teeth, a rotary knob, a stopper element defining a first wedge-shaped end and a second cylindrical end, a first and second spring, and a casing member. In assembly, the rotatable shaft is passed through the aperture defined in the casing member and rotatably attached thereto by means of the first spring. The stopper element is then connected to a wall of the casing member, by means of the second spring. Thereafter, the gear member is fixedly attached on the rotatable shaft, proximal to the second end thereof, such that the wedge-shaped of the stopper element meshes with one of the plurality of teeth of the gear member, to lock the gear member. Further an electrically conductive link member is attached on the second end of the

rotatable shaft. A cover member defining a plurality of conductive elements thereon is then fixedly attached to the casing member. Finally, the rotary knob is connected to the first end of the rotatable shaft, for completing an assembly of the conventional rotary switch configuration.
In operation, the rotary knob can be controllably operated by a user to lock the gear member in a default position or any one of a plurality of non-default positions. However, in the event of any accidents during operation of the mixer grinder, such as, but not limited to sudden opening of a jar lid, malfunction of the jar unit, and the like, the conventional rotary switch configuration is to be manually switched to the default position from any of the subsequent non-default positions. This manually switching in the existing art results in an unnecessary delay in cutting off the power supply to the mixer grinder, which is a high priority concern.
Accordingly, there is a need to provide a rotary switch configuration for the mixer grinder, for quick and easy power supply cut off, independent of the non-default position of the rotary knob.
SUMMARY OF THE INVENTION
This section is intended to introduce certain aspects of the disclosed invention in a simplified form, and is not intended to identify the key advantages or features of the present disclosure.
In an aspect of the present invention there is provided a rotary switch configuration for a mixer grinder, the configuration comprising: a disc member defining a plurality of protrusions on at least a portion of a periphery thereof; a rotatable shaft comprising a first end and a second end, the shaft connected to the disc member, and adapted to pass through a central aperture defined by the disc member; an adjustment member connected to the first end of the rotatable shaft; a spring-loaded plunger; and a stopper element configured to mate with one of the plurality of protrusions of the disc member; wherein the adjustment member mediates the engagement of the stopper element to lock the disc member from a default position

to at least one of a plurality of non-default positions; or the adjustment member mediates the disengagement of the stopper element from the disc member by engaging the spring-loaded plunger to return the disc member from any one of the plurality of non-default position to the default position.
In an aspect of the present invention, the rotary switch configuration comprises at least a torsion spring connected to the rotatable shaft and configured to return the disc member from any one of the plurality of non-default positions to the default position.
In yet another aspect of the present invention, the torsion spring is located between the disc member and the adjustment member.
In another aspect of the present invention, the default position of the disc member cuts off a power supply to a motor of the mixer grinder.
In an aspect of the present invention, the spring-loaded plunger defines a male guide, while the stopper element defines a female guide, such that the male guide of the spring-loaded plunger is adapted to mate with the female guide of the stopper element to enable disengagement of the stopper element from the disc member.
In another aspect of the present invention, the rotary switch configuration comprises a casing member defining an aperture thereon adapted to receive the rotatable shaft therethrough.
In yet another aspect of the present invention, the rotatable shaft is rotatably connected to the casing member, by means of the torsion spring.
In still another aspect of the present invention, the adjustment member and the disc member are fixedly connected to the rotatable shaft by means of an interference fit attachment.
In an aspect of the present invention, the adjustment member is a user operable rotary knob.

In an aspect of the present invention, each of the plurality of protrusions defined by the disc member extends radially outwards from the periphery of the disc member.
In another aspect of the present invention, each of the plurality of protrusions defined by the disc member is a spur gear tooth.
In yet another aspect of the present invention, the stopper element comprises a wedge-shaped first end configured to mate with any one of the plurality of protrusions defined by the disc member, for locking the disc member in any one of the plurality of non-default positions.
In still another aspect of the present invention, the stopper element comprises a second end distal to the first end, wherein the second end is connected with at least a compression spring.
In yet another aspect of the present invention, at least the compression spring is a helical compression spring.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings. These and other details of the present invention will be described in connection with the accompanying drawings, which are furnished only by way of illustration and not in limitation of the invention, and in which drawings:
Figure 1a illustrates a side section view of a rotary switch configuration, in accordance with an embodiment of the present disclosure.
Figure 1b illustrates a front section view of the rotary switch configuration, in accordance with an embodiment of the present disclosure.

Figure 1c illustrates an exploded view of the rotary switch configuration, in accordance with an embodiment of the present disclosure.
Figure 2 illustrates a perspective view of a mixer grinder, deploying therein the rotary switch configuration, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent, however, that embodiments of the present invention may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address any of the problems discussed above or might address only one of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein. Example embodiments of the present invention are described below, as illustrated in various drawings in which like reference numerals refer to the same parts throughout the different drawings.
The present invention provides a rotary switch configuration (100) for a mixer grinder (200), the configuration (100) comprising: a disc member (102) defining a plurality of protrusions on at least a portion of a periphery thereof; a rotatable shaft (104) comprising a first end and a second end, the rotatable shaft (104) connected to the disc member (102), and adapted to pass through a central aperture defined by the disc member (102); an adjustment member (106) connected to the first end of the rotatable shaft (104); a spring-loaded plunger (110); and a stopper element (112) configured to mate with one of the plurality of protrusions of the disc member (102); wherein the adjustment member (106) mediates the engagement of the stopper element (112) to lock the disc member (102) from a default position to at least one of a plurality of non-default positions; or the adjustment member (106) mediates

the disengagement of the stopper element (112) from the disc member (102) by engaging the spring-loaded plunger (110) to return the disc member (102) from any one of the plurality of non-default positions to the default position.
In an embodiment, the plurality of non-default positions of the disc member (102) corresponds to a plurality of pre-defined speeds of the motor of the mixer grinder (200). In an embodiment, the disc member (102) has 2, 3, 4, or 5 pre-defined speeds. In an embodiment, the plurality of the pre-defined speeds include a constant speed. In an embodiment, the plurality of the pre-defined speeds can be pulsed. In an embodiment, the plurality of speeds includes at least a pre-defined constant speed and at least a pulsed speed.
In an embodiment, the rotary switch configuration (100) comprises at least a torsion spring (108) connected to the rotatable shaft (104) and configured to return the disc member (102) from any one of the plurality of non-default positions to the default position. In an embodiment, the torsion spring (108) is located between the disc member (102) and the adjustment member (106). In an embodiment, the default position of the disc member (102) cuts off a power supply to a motor of the mixer grinder (200).
In another embodiment, the spring-loaded plunger (110) defines a male guide, while the stopper element (112) defines a female guide, such that the male guide of the spring-loaded plunger (110) is adapted to mate with the female guide of the stopper element (110) to enable disengagement of the stopper element (112) from the disc member (102). The male guide of the spring-loaded plunger (110) mates with the female guide of the stopper element (112) when the adjustment member (106) is engaged in the axial axis. In a default position of the adjustment member (106), the spring-loaded plunger (110) is not mated with the stopper element (112). In a non-default position, the spring-loaded plunger (110) is mated with the stopper element (112). In an embodiment, the non-default position is a transient position.

In yet another embodiment, the rotary switch configuration (100) comprises a casing member (114) defining an aperture thereon adapted to receive the rotatable shaft (104) therethrough. In an embodiment, the rotatable shaft (104) is rotatably connected to the casing member (114), by means of the torsion spring (108). In an embodiment, the adjustment member (106) and the disc member (102) are fixedly connected to the rotatable shaft (104) by means of an interference fit attachment.
In another embodiment, the adjustment member (106) is a user operable rotary knob. In an embodiment, each of the plurality of protrusions defined by the disc member (102) extends radially outwards from the periphery of the disc member (102). In still another embodiment, each of the plurality of protrusions defined by the disc member (102) is a spur gear tooth.
In another embodiment, the stopper element (112) comprises a wedge-shaped first end configured to mate with any one of the plurality of protrusions defined by the disc member (102), for locking the disc member (102) in any one of the plurality of non-default positions. In yet another embodiment, the stopper element (112) comprises a second end distal to the first end, wherein the second end is connected with at least a compression spring (116). In an embodiment, at least the compression spring (116) is a helical compression spring. In a default position, the wedge-shaped first end of the stopper element (112) engages a spur gear tooth on the disc member (102).
Figure 1a illustrates a side section view of the rotary switch configuration (100), in accordance with an embodiment of the present disclosure.
Figure 1b illustrates a front section view of the rotary switch configuration (100), in accordance with an embodiment of the present disclosure.
Figure 1c illustrates an exploded view of the rotary switch configuration (100), in accordance with an embodiment of the present disclosure.

Figures 1a, 1b, and 1c are to be viewed in conjunction with each other, in order to better understand the concepts of the present disclosure. A detailed structure and arrangement of the rotary switch configuration (100) is described hereinafter in detail.
With reference to Figures 1a, 1b, and 1c, the rotary switch configuration (100) comprises a disc member (102), a rotatable shaft (104), an adjustment member (106), a spring-loaded plunger (110), and a stopper element (112). The disc member (102) defines a plurality of protrusions (118) on at least a portion of the periphery thereof, and a central aperture (102a) (as shown in Figure 1b). Each of the plurality of protrusions (118) defined by the disc member (102) extends radially outwards from the periphery of the disc member (102). Notably, each of the plurality of protrusions (118) defined by the disc member is a spur gear tooth (as shown in Figure 1b). The rotatable shaft (104) is adapted to pass through the central aperture (102a) defined by the disc member (102), and comprises a first end (104a) and a second end (104b). The adjustment member (106) is connected to the first end (104a) of the rotatable shaft (104), wherein the adjustment member (106) is a user operable rotary knob (as shown in Figure 1a). Notably, the adjustment member (106) and the disc member (102) are fixedly connected to the rotatable shaft (104) by means of an interference fit attachment. A person skilled in the art may also envision other known attachment means for fixedly connecting the adjustment member (106) and the disc member (102) to the rotatable shaft (104), and the same may be construed to be within the scope of the present disclosure.
The stopper element (112) is configured to mate with any one of the plurality of protrusions (118) of the disc member (102). Notably, the stopper element (112) comprises a wedge-shaped first end (112a) configured to mate with any one of the plurality of protrusions (118) defined by the disc member (102), for locking the disc member (102) in any one of a plurality of non-default positions. The plurality of non-default positions of the disc member (102) corresponds to plurality of speeds of a motor (not shown) of the mixer grinder (200), while a default position of the disc member (102) cuts off a power supply to the motor of the mixer grinder (200).

In other words, each of the plurality of non-default positions corresponds to different speeds of processing of food articles by the mixer grinder (200). Furthermore, the stopper element (112) comprises a second end (112b) distal to the first end (112a), wherein the second end (112b) is connected with at least a compression spring (116). Notably, the compression spring (116) is a helical compression spring. It may be noted that although, the shape of the first end (112a) of the stopper element (112) has been defined as wedge-shaped for exemplary purposes, it is not intended to limit scope of the invention. It may be obvious to a person skilled in the art that the first end (112a) of the stopper element (112) can be of different shapes, which are capable of mating with the plurality of protrusions (118) defined by the disc member (106), to lock the disc member (106).
In addition to the abovementioned components, the rotary switch configuration (100) further comprises at least a torsion spring (108) connected to the rotatable shaft (104). Particularly, the torsion spring (108) is configured to return the disc member (102) from any one of the plurality of non-default positions to the default position. The torsion spring (108) is located between the disc member (102) and the adjustment member (106) (as shown in Figure 1a). In an exemplary embodiment, the rotary switch configuration (100) further comprises a casing member (114), wherein the casing member (114) defines an aperture (114a) thereon adapted to receive the rotatable shaft (104) therethrough. Notably, the rotatable shaft (104) is rotatably connected to the casing member (114), by means of the torsion spring (108). Furthermore, the casing member (114) houses and supports each of the described components of the rotary switch configuration (100), therein.
In operation, rotation of the adjustment member (106), by a user, mediates the engagement of the stopper element (112) to lock the disc member (102) from a default position to at least one of a plurality of non-default positions. Additionally, the adjustment member (106) can also mediate the disengagement of the stopper element (112) from the disc member (102) by engaging the spring-loaded plunger (110) to return the disc member (102) from any one of the plurality of non-default positions to the default position. The return of the disc member (102) from a non-

default position to default position when the stopper element (112) is disengaged from the disc member (102) is due to the torsion spring (108) releasing the stored mechanical energy and exerting torque in the opposite direction.
Notably, the spring-loaded plunger (110) defines a male guide (110a), while the stopper element (112) defines a female guide (112c), such that the male guide (110a) of the spring-loaded plunger (110) is adapted to mate with the female guide (112c) of the stopper element (112) to enable disengagement of the stopper element (112) from the disc member (102).
Figure 2 illustrates a perspective view of the mixer grinder (200) deploying therein the rotary switch configuration (100), in accordance with an embodiment of the present disclosure. With reference to Figure 2, the mixer grinder (200) comprises a base unit (202) and a jar unit (204). The jar unit (204) carries food articles and may be connected to the base unit (202). Notably, the rotary switch configuration (100) is installed in the base unit (202), more particularly, in a main housing (206) thereof, and is capable of facilitating adjustment of speed of processing of the food articles in the jar unit (204).
Advantageously, the rotary switch configuration (100) of the present invention provides for quick and easy cutting-off of power supply to the mixer grinder (200), independent of the non-default position of the adjustment member (106) i.e., the user operable rotary knob. Thus, this eliminates the delay caused in the existing arts in turning the rotary knob manually from any of the plurality of non-default positions to the default position either in a step-wise manner, which takes time, or in a single step manually, which has the risk of excess torque being operated by the user, which can result in damage of rotary knob of the art. The present invention provides a consistent torque to the mechanism to return the disc member (102) and the adjustment member (106) (rotary knob) to default position, thus avoiding damage. Further, the arrangement provided is simple and intuitive, and avoids complicated parts. Thus, the present invention proves to maximize the utility of the rotary switch configuration (100) of the mixer grinder (200).

While the preferred embodiments of the present invention have been described hereinabove, it should be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims. It will be obvious to a person skilled in the art that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.
REFERENCE NUMERALS
100 – Rotary switch configuration
102 – Disc member
102a – Central aperture
104 – Rotatable shaft
104a – First end
104b – Second end
106 – Adjustment member
108 – Torsion spring
110 – Spring-loaded plunger
110a – Male guide
112 – Stopper element
112a – First end
112b – Second end

112c – Female guide 114 – Casing member 114a – Aperture 116 – Compression spring 118 – Protrusions 200 – Mixer grinder 202 – Processing unit 204 – Jar unit 206 – Main housing

I/We Claim:
1. A rotary switch configuration (100) for a mixer grinder (200), the
configuration (100) comprising:
a disc member (102) defining a plurality of protrusions (118) on at least a portion of a periphery thereof;
a rotatable shaft (104) comprising a first end (104a) and a second end (104b), the shaft (104) connected to the disc member (102), and adapted to pass through a central aperture (102a) defined by the disc member (102);
an adjustment member (106) connected to the first end (104a) of the rotatable shaft (104);
a spring-loaded plunger (110); and
a stopper element (112) configured to mate with one of the plurality of protrusions (118) of the disc member (102); wherein
the adjustment member (106) mediates the engagement of the stopper element (112) to lock the disc member (102) from a default position to at least one of a plurality of non-default positions; or
the adjustment member (106) mediates the disengagement of the stopper element (112) from the disc member (102) by engaging the spring-loaded plunger (110) to return the disc member (102) from any one of the plurality of non-default position to the default position.
2. The rotary switch configuration (100) as claimed in claim 1, comprising at least a torsion spring (108) connected to the rotatable shaft (104) and configured to return the disc member (102) from any one of the plurality of non-default position to the default position.
3. The rotary switch configuration (100) as claimed in claim 2, wherein the torsion spring (108) is located between the disc member (102) and the adjustment member (106).

4. The rotary switch configuration (100) as claimed in claim 1, wherein the default position of the disc member (102) cuts off a power supply to a motor of the mixer grinder (200).
5. The rotary switch configuration (100) as claimed in claim 1, wherein the spring-loaded plunger (110) defines a male guide (110a), while the stopper element (112) defines a female guide (112c), such that the male guide (110a) of the spring-loaded plunger (110) is adapted to mate with the female guide (112c) of the stopper element (112) to enable disengagement of the stopper element (112) from the disc member (102).
6. The rotary switch configuration (100) as claimed in claim 1, comprising a casing member (114) defining an aperture (114a) thereon adapted to receive the rotatable shaft (104) therethrough.
7. The rotary switch configuration (100) as claimed in claim 6, wherein the rotatable shaft (104) is rotatably connected to the casing member (114), by means of the torsion spring (108).
8. The rotary switch configuration (100) as claimed in claim 1, wherein the adjustment member (106) and the disc member (102) are fixedly connected to the rotatable shaft (104) by means of an interference fit attachment.
9. The rotary switch configuration (100) as claimed in claim 1, wherein the adjustment member (106) is a user operable rotary knob.
10. The rotary switch configuration (100) as claimed in claim 1, wherein each of the plurality of protrusions (118) defined by the disc member (102) extends radially outwards from the periphery of the disc member (102).
11. The rotary switch configuration (100) as claimed in claim 1, wherein each of the plurality of protrusions (118) defined by the disc member (102) is a spur gear tooth.

12. The rotary switch configuration (100) as claimed in claim 1, wherein the stopper element (112) comprises a wedge-shaped first end (112a) configured to mate with any one of the plurality of protrusions (118) defined by the disc member (102), for locking the disc member (102) in any one of the plurality of non-default positions.
13. The rotary switch configuration (100) as claimed in claim 1, wherein the stopper element (112) comprises a second end (112b) distal to the first end (112a), wherein the second end (112b) is connected with at least a compression spring (116).
14. The rotary switch configuration (100) as claimed in claim 13, wherein the compression spring (116) is a helical compression spring.