Field of the invention:
The present invention generally relates to a micro switch, particularly a micro switch with a latchable mechanism.

Background of the invention:
A push button micro switch comprising a slider which latches in a depressed position when pushed once and unlatches when pushed again is known in the art.

For instance, US 4,218,598 discloses a switch having a latching mechanism which comprises a stiff wire, a first end of which is retained in a hole and a second end of which is slidable in a heart shaped groove of a slider in such a manner that the slider latches in a depressed position when pushed once and unlatches when pushed again. A similar construction is demonstrated in US 4,449,022; US 4,382,167; US 3,582,592.

In an alternative arrangement as shown in US 3,707,610; the latching mechanism comprises a flat headed straight pin inserted through a slot. The flat headed straight pin is in engagement with the heart shaped groove of the slider. An enlarged flat head on the pin is held between a flat surface surrounding the slot and a retaining plate, so that the pin remains perpendicular to the plane of the upper surface of the slider.

In an alternative arrangement as shown in US 3,229,548; the latching mechanism comprises a flat headed pin having a first end mounted loosely to a spring means and having a second end in engagement with the heart shaped groove of the slider.

In all of these latching mechanisms, the pin either in the form of stiff wire or in the form of flat headed straight pin exhibits pivotal movement. In this construction there exists a possibility that once in a while the second end of the stiff wire or the pin portion comes out of the heart shaped groove. Thus, the slider does not get latched when pushed once. In some instances, the number of parts used is high or the manner of interconnection of the flat headed straight pin is complicated. Hence, the prior art products suffer from a variety of disadvantages known in the art. Apart from the above, these prior art switches cannot be substantially modified to accommodate for changes in size (especially reduction in size), shape, and orientation of various elements such as fixed contact, moving contacts, carrier member etc. Thus, an object of the invention is to provide a micro switch with a latchable mechanism which overcomes the disadvantages in the prior art.

Summary of the invention:
This summary is provided to introduce a selection of concepts in a simplified format that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention, and nor is it intended for determining the scope of the invention.

Accordingly, the present invention provides a micro switch (10) comprising a housing (12) having a hollow internal region therein; a set of fixed contact terminals (14) accommodated at least partially within the housing (12); a carrier member (16) accommodated at least partially within the housing (12), the carrier member (16) being adapted to exhibit sliding movement along a first direction within the housing (12), the carrier member (16) accommodating a moving contact member (18); and a latching mechanism (20) adapted to latch the carrier member (16) in a pre-designated position within the housing (12), the latching mechanism (20) comprising a cam pin (22) co-operating with a heart shaped cam profile (24). In an embodiment of the invention, the cam pin (22) is accommodated in a channel (26), the cam pin (22) being adapted to exhibit movement along a second direction within the channel (26), the second direction being perpendicular to the first direction.

To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

Brief description of the drawings:
In order that the invention may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying drawings, where like reference numerals refer to identical or functionally similar elements throughout the separate views. The figures together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present invention where:
Figure 1 illustrates an exploded view of a micro switch (10) constructed in accordance with a first embodiment of the invention;
Figure 2 illustrates an inside view of the open box structure (36) constructed in accordance with the first embodiment of the invention;
Figure 3 (a) illustrates a first perspective view of the carrier member (16) and the first resilient member (44) showing the heart shaped cam profile (24) formed on a first lateral side wall of the carrier member in accordance with the first embodiment of the invention;
Figure 3 (b) illustrates a second perspective view of the carrier member (16) and the first resilient member (44) showing the moving contact terminal (18) accommodated on a second lateral side wall of the carrier member in accordance with the first embodiment of the invention;
Figure 4 illustrates a perspective view of the base plate (38) having the first and second walls (40, 42) with the set of fixed contacts terminals (14) being provided on the first wall (40) and the channel (26) provided on the second wall (42) in accordance with the first embodiment of the invention;
Figure 5 illustrates a perspective view of the base plate (38) accommodating the cam pin (22) within the channel (26) provided on the second wall (42) in accordance with the first embodiment of the invention;
Figure 6 illustrates a sectional view of the micro switch (10) constructed in accordance with the first embodiment of the invention;
Figure 7 (a) illustrates the micro switch (10) constructed in accordance with the first embodiment of the invention in a non-operated state;
Figure 7 (b) illustrates the micro switch (10) constructed in accordance with the first embodiment of the invention in a latched condition;
Figure 7 (c) illustrates the micro switch (10) constructed in accordance with the first embodiment of the invention in a full-stroke condition;
Figure 8 illustrates the movement of the pin structure (30) within the heart shaped cam profile (24) in accordance with an embodiment of the invention;
Figure 9 illustrates an exploded view of a micro switch (10) constructed in accordance with a third embodiment of the invention; and
Figure 10 illustrates sectional of a micro switch (10) constructed in accordance with the third embodiment of the invention.

It may be noted that to the extent possible, like reference numerals have been used to represent like elements in the drawings. Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of aspects of the present invention. Furthermore, the one or more elements may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

Detailed Description of the Invention:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.

As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present subject matter. Thus, appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a nonexclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or subsystems or elements or structures or components proceeded by "comprises... a" does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.

As used herein, and unless the context dictates otherwise, the terms "coupled to", “connected to”, “operably connected to”, “operatively connected to” are intended to include both direct connection / coupling (in which two elements that are coupled / connected to each other contact each other) and indirect coupling / connection (in which at least one additional element is located between the two elements). Therefore, the terms "coupled to" and "coupled with" are used synonymously. Similarly, the terms “connected to” and “connected with” are used synonymously.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

Embodiments of the present subject matter will be described below in detail with reference to the accompanying drawings.

Referring to Figure 1, which is an exploded view of a micro switch (10) constructed in accordance with a first embodiment of the invention, it can be observed that the micro switch (10) comprises a housing (12) having a hollow internal region therein. In an embodiment of the invention, the housing (12) can be formed in two parts, namely an open box structure (36) and a base plate (38) co-operating with the open box structure (36) to define the hollow internal region. The micro switch (10) further comprises a set of fixed contact terminals (14) accommodated at least partially within the housing (12). The micro switch (10) further comprises a carrier member (16) accommodated at least partially within the housing (12). The carrier member (16) accommodates a moving contact member (18). The carrier member (16) is adapted to exhibit sliding movement along a first direction within the housing (12). The micro switch (10) further comprises a latching mechanism (20) adapted to latch the carrier member (16) in a pre-designated position within the housing (12).

In an embodiment of the invention, the latching mechanism (20) comprises a cam pin (22) co-operating with a heart shaped cam profile (24). In an embodiment of the invention, the cam pin (22) is accommodated in a channel (26). In a furthermore embodiment of the invention, the cam pin (22) is adapted to exhibit movement along a second direction within the channel (26), the second direction being perpendicular to the first direction. In an embodiment of the invention, the cam pin (22) comprises a flat plate (28) and a pin structure (30) projecting from the flat plate (28).

It can be observed that in the embodiment shown in Figure 1 and more particularly in Figures 3(a) and 3(b), the heart shaped cam profile (24) is formed on a lateral side wall (321, ... 324) of the carrier member (16). Also, the moving contact member (18) is provided on a lateral side wall (321, ... 324) of the carrier member (16). More particularly, the heart shaped cam profile (24) is formed on a first lateral side wall (321) of the carrier member (16) while the moving contact member (18) is provided on a second lateral side wall (322) of the carrier member (16), the first lateral side wall (321) being opposite to the second lateral side wall (322). It is however possible to dispose the adjacent lateral side walls of the carrier member, instead of being disposed on opposite lateral side walls.

It can be observed that in the embodiment shown in Figure 1 and more particularly in Figure 4, the base plate (38) defines a first and a second walls (40, 42), the first and second walls protruding into the hollow internal region. The set of fixed contact terminals (14) are provided on one of the first and a second walls (40, 42) so as to face the moving contact member (18) provided on a lateral side wall (321, ... 32n) of the carrier member (16). The channel (26) is formed on one of the first and a second walls (40, 42) so as to face the heart shaped cam profile (24) which is formed on a lateral side wall (321, ... 324) of the carrier member (16). Figure 4 shows the set of fixed contact terminals (14) as being provided on the first wall (40) while the channel (26) is shown as having been formed on the second wall (42). As can be seen from Figure 5, the base plate (38) accommodates the cam pin (22) within the channel (26) provided on the second wall (42).

As can be seen from Figure 6, which is a sectional view of the micro switch (10), when the cam pin (22) is accommodated within the channel (26), the flat plate (28) is free to move within channel (26) while the pin structure (30) projects from the channel (26) and gets engaged with the heart shaped cam profile (24). In this embodiment, depending upon the extent to which the carrier member (16) is moved in the first direction and depending upon the shape of the heart shaped cam profile (24), the cam pin (22) moves within the channel (26).

Now referring back to Figure 1, the micro switch (10) further comprises a first resilient member (44) adapted to apply a restoration force on to the carrier member (16). The first resilient member (44) is preferably disposed between the underside of the carrier member (16) and the base plate (38). Also, the micro switch (10) further comprises a second resilient member (46) disposed so as to exert a positive contact making pressure on the moving contact member (18). Also, there may be provided a grommet (48) that surrounds an opening (not specifically numbered) in the housing (12) through which the carrier member protrudes at least partially outside. The grommet (48) acts to reduce ingress of foreign contaminants (such as dust, water droplets, moisture, etc.) into the hollow internal region defined by the housing.

The micro switch (10) constructed in accordance with the teachings of the invention exhibits three states namely a non-operated state which is illustrated in Figure 7(a). When the carrier member is depressed once starting from the non-operated state, the micro switch attains the latched condition which is illustrated in Figure 7(b). When the carrier member is depressed once again (starting from the latched condition) the micro switch reaches the fully depressed state as shown in Figure 7(c) and once the carrier member is released from the fully depressed state, the micro switch returns to the non-operated state.

Now referring to Figure 8, there is illustrated the movement of the pin structure (30) within the heart shaped cam profile (24). When the micro switch is in non-operated state, the pin structure resides at the location indicated as 301. When the carrier member (16) is depressed once starting from the non-operated state, because of the movement of the carrier member (16) in the first direction and the movement of the cam pin (22) and more particularly the flat plate (28) in the second direction (which is perpendicular to the first direction), the pin structure (30) is effectively seen to follow the path shown as“A”and reach the position marked as 302. Once the carrier member (16) is released at this state, the pin structure (30) follows the path shown as“B”and gets parked at position marked as 303, thereby latching the carrier member (16) in a pre-designated position within the housing (12). When the carrier member (16) is depressed once again starting from the latched state, the pin structure (30) is effectively seen to follow the path shown as“C”and reach the position marked as 304. Once the carrier member (16) is released at this state, the pin structure (30) follows the path shown as“D”and reverts back to the location indicated as 301.

While in the first embodiment shown in Figures 1 to 8, the channel (26) is shown to be formed on one of the first and a second walls (40, 42) of the base plate (38) and the heart shaped cam profile (24) is shown to be formed on a lateral side wall (321, ... 324) of the carrier member (16), whereas in a second embodiment of the invention (which is not specifically shown) it is possible that the channel (26) is formed on a lateral side wall (321, ... 324) of the carrier member (16) and the heart shaped cam profile (24) is formed on one of the first and the second walls (40, 42) of the base plate (38). Thus, in such a case (which is not specifically illustrated), the cam pin (22) is accommodated by the carrier member (16). It may however be noted that the construction as per the second embodiment is less preferential as compared to the construction shown in Figures 1 to 8.

While in the first embodiment shown in Figures 1 to 8, the base plate (38) is shown to comprise of the first and the second walls (40, 42) protruding into the hollow internal region, in some embodiments of the invention, the base plate (38) may not be having both of the first and second walls (40, 42).

Referring in this regard to Figure 9 and Figure 10, which are an exploded view and a sectional view of a micro switch (10) constructed in accordance with a third embodiment of the invention, when the base plate (38) is devoid of both the first and second walls (40, 42); the channel (26) may be formed on a lateral side wall (341, ... 34n) of the housing (12) while the heart shaped cam profile (24) may be formed on a lateral side wall (321, ... 32n) of the carrier member (16) facing the channel (26). Thus, in this case, the cam pin (22) may be accommodated in the channel (26) formed in one of the lateral side wall (341, ... 34n) of the housing (12). Also, in such a case, the set of fixed contact terminals (14) are provided on a lateral side wall (341, ... 34n) of the housing (12) and the moving contact member (18) is provided on a lateral side wall (321, ... 32n) of the carrier member (16) facing the fixed contact terminals (14). As the micro switch (10) shown in Figures 9 and 10 is similar to the micro switch (10) shown in Figures 1 to 8 in relation to remaining aspects, the remaining aspects are not being described. It may however be noted that the construction as per the third embodiment is less preferential as compared to the construction shown in Figures 1 to 8.

Although not illustrated in a fourth embodiment of the invention, when the base plate (38) is devoid of both the first and second walls (40, 42); the heart shaped cam profile (24) is formed on a lateral side wall (341, ... 34n) of the housing (12) while the channel (26) is provided on a lateral side wall (321, ... 32n) of the carrier member (16) facing the heart shaped cam profile (24). Thus, in the fourth embodiment, the cam pin (22) may be accommodated in the channel (26) formed in one of the lateral side wall (321, ... 32n) of the carrier member (16). Also, in the fourth embodiment, the set of fixed contact terminals (14) are provided on a lateral side wall (341, ... 34n) of the housing (12) and the moving contact member (18) is provided on a lateral side wall (321, ... 32n) of the carrier member (16) facing the fixed contact terminals (14). It may however be noted that the construction as per the fourth embodiment is less preferential as compared to the construction shown in Figures 1 to 8.

In a fifth embodiment of the invention, the base plate (38) may merely comprise one wall (40) protruding into the hollow internal region. In such a case, the channel (26) may be formed on a lateral side wall (341, ... 34n) of the housing (12) while the heart shaped cam profile (24) may be formed on a lateral side wall (321, ... 32n) of the carrier member (16) facing the channel (26). Also, in such a case, the set of fixed contact terminals (14) are provided on the side wall (40) formed on the base plate (38) and the moving contact member (18) is provided on a lateral side wall (321, ... 32n) of the carrier member (16) facing the fixed contact terminals (14). It may however be noted that the construction as per the fifth embodiment is less preferential as compared to the construction shown in Figures 1 to 8.

In the construction as per the teachings of the invention, the cam pin (22) is constantly co-operating with the heart shaped cam profile (24) and at no point during operation, the pin structure (30) comes out of the heart shaped cam profile (24). Thus, the constant co-operation between the heart shaped cam profile (24) and the cam pin (22) is the source of movement of the cam pin (22) along the second direction within the channel (26). Also, when the construction as mentioned above is followed, the number of parts used is relatively less. Furthermore, in the construction as mentioned above, the assembling of the micro switch (10) becomes easy. For instance, the cam pin (22) can be easily placed within the channel as compared to the prior art processes.

While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.

Claims:

We Claim:

1. A micro switch (10) comprising:
a housing (12) having a hollow internal region therein;
a set of fixed contact terminals (14) accommodated at least partially within the housing (12);
a carrier member (16) accommodated at least partially within the housing (12), the carrier member (16) being adapted to exhibit sliding movement along a first direction within the housing (12), the carrier member (16) accommodating a moving contact member (18);
a latching mechanism (20) adapted to latch the carrier member (16) in a pre-designated position within the housing (12), the latching mechanism (20) comprising a cam pin (22) co-operating with a heart shaped cam profile (24);
characterized in that the cam pin (22) is accommodated in a channel (26), the cam pin (22) being adapted to exhibit movement along a second direction within the channel (26), the second direction being perpendicular to the first direction.

2. The micro switch as claimed in claim 1, wherein the cam pin (22) comprises a flat plate (28) and a pin structure (30) projecting from the flat plate (28).

3. The micro switch as claimed in claim 1, wherein the heart shaped cam profile (24) is formed on a lateral side wall (321, ... 32n) of the carrier member (16) and the channel (26) is formed on a lateral side wall (341, ... 34n) of the housing (12) facing the heart shaped cam profile (24).

4. The micro switch as claimed in claim 1, wherein the heart shaped cam profile (24) is formed on a lateral side wall (341, ... 34n) of the housing (12) and the channel (26) is formed provided on a lateral side wall (321, ... 32n) of the carrier member (16) facing the heart shaped cam profile (24).

5. The micro switch as claimed in claim 1, wherein the set of fixed contact terminals (14) are provided on a lateral side wall (341, ... 34n) of the housing (12) and the moving contact member (18) is provided on a lateral side wall (321, ... 32n) of the carrier member (16) facing the fixed contact terminals (14).

6. The micro switch as claimed in claim 1, wherein the housing (12) comprises an open box structure (36) and a base plate (38) co-operating with the open box structure (36) to define the hollow internal region.

7. The micro switch as claimed in claim 6, wherein the base plate (38) defines a first and a second walls (40, 42), the first and second walls protruding into the hollow internal region.

8. The micro switch as claimed in claim 7, wherein the heart shaped cam profile (24) is formed on a lateral side wall (321, ... 32n) of the carrier member (16) and the channel (26) is formed on one of the first and the second walls (40, 42) so as to face the heart shaped cam profile (24).

9. The micro switch as claimed in claim 7, wherein the heart shaped cam profile (24) is formed on one of the first and the second walls (40, 42) and the channel (26) is formed provided on a lateral side wall (321, ... 32n) of the carrier member (16) so as to face the heart shaped cam profile (24).

10. The micro switch as claimed in claim 7, wherein the set of fixed contact terminals (14) are provided on one of the first and the second walls (40, 42) and the moving contact member (18) is provided on a lateral side wall (321, ... 32n) of the carrier member (16) so as to face the fixed contact terminals (14).

11. The micro switch as claimed any of the claim 7, wherein the heart shaped cam profile (24) is provided on the first wall (40) and the set of fixed contact terminals (14) are provided on the second wall (42).

12. The micro switch as claimed in claim 1, further comprising a first resilient member (44) adapted to apply force on to the carrier member (16).