Description:
FIELD OF THE INVENTION
Embodiments of the invention in general relates to the field of electrical switches, more particularly to mechanically operated electrical switches used for switching on and off lights and other electrical appliances in day-to-day life.

BACKGROUND OF THE INVENTION
Electrical switches are electromechanical devices used in electrical circuits to control power, provide a means for manual control of machine and process functions, control lighting, and so on. Electrical switches come in a variety of styles and actuated by hand, foot, or through the detection of pressure, level, or objects.

Switches can be of mechanical or electronic type, wherein mechanical switches must be activated physically, by moving, pressing, releasing, or touching its contacts.

Mechanical switches can be classified into different types based on several factors such as method of actuation (manual, limit and process switches), number of contacts (single contact and multi contact switches), number of poles and throws (SPST, DPDT, SPOT, etc.), operation and construction (push button, toggle, rotary, joystick, etc.), based on state (momentary and locked switches), etc.

The toggle mechanism provides "snap-action" using an "over-centre" geometry. William J. Newton and Morris Goldberg patented the design in 1916.

An alternative design to the toggle switch is the rocker switch. Switches of this design sit almost flush with the wall plate, activated by "rocking" a flat, broad lever.

The present invention relates to switches in electrical circuits more particular to a type, which is known as mechanical rocker switches, which will be having less noise with soft operation.

One such type is mercury switch, which worked satisfactorily but discontinued because of the hazards caused by mercury.

A conventional rocker switch consists of two metal contacts and one moving rocker which is spring loaded. The rocker sits on one of the metal contacts and through an actuating lever it is brought in contact with the other metal contacts.

Since the rocker is loaded with spring, it is under a particular pressure. Turning the actuator gradually stretches the spring. When the mechanism passes over the center point, the spring energy is released and the spring, rather than the actuator, drives the contacts rapidly and forcibly to the closed position with an audible "snapping" sound. This mechanism is safe, reliable, and durable, but produces a loud snap or click every time the front end of rocker comes in contact with the metal contact during switch on operation.

Moreover, when the switch is offed, the contacts break and back end of rocker strikes the plastic of the switch frame thus again making an impact noise.

With changing times and preferences, electrical switches are not only looked upon as devices that promptly switch on/off the lights and electrical devices but also add to the aesthetics of one's home.

Modular switches also find their application in hospitals, hospitality business, libraries, cleanroom etc. In order to meet the diversified requirements and most prominent being "a noise-free application ", silent/noiseless switch tends to be a market driver.

Silent switching is an excitement attribute for a modular switch in luxury and hospitality segment. Silent switching is a performance attribute in segments like hospitals, clean rooms and libraries.

Reference is drawn to US2743330A, which relates to overcome the difficulty of mercury switch to provide a light mechanism for nullifying noise. It employs a cam follower mechanism for making and breaking action along with two separate bumpers for noise cancellation.

Reference is drawn to US2985725A relating to an electrical switch that will be silent in operation without any sound absorption material. The contacts here will be magnetically engaged with one on the rotating shaft and one on the frame, with at least one of the members magnetized to provide an attraction force.

Reference is further drawn to US3354275A, disclosing an electrical switch, which will be quieter in operation and easily adaptable to single pole double pole, and two-way switches. This also employs cam follower mechanism along with rubber bumpers to quieten the operation.

Yet another reference is made to US1720395A teaching an electrical switch having a contact bar that can be manually shifted to effect the opening and closing of a circuit through the switch and which, at its ends, operates against air cushions which so retard it that its movements under spring tension are almost noiseless.

In view of the prior art, there is a dire need of an electrical switch that is silent in operation at the same time will not degrade the life of switch maintaining at least 2.5 lakh operations.

SUMMARY OF THE INVENTION
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

According to one aspect of the present invention, noiseless electrical modular switch comprising: a bottom housing adapted to fit a sub-assembly damper, wherein the sub-assembly damper fitted within the bottom housing comprises an assembly of a primary damper and a plurality of fixed metal contacts adapted to fit inside said primary damper, such that the plurality of fixed metal contacts is in indirect contact with the bottom housing, so as to attenuate any sound wave generated due to any movement of the internal contacts of the modular switch.

According to an embodiment, the modular switch comprises: a secondary damper adapted to fit with the sub-assembly damper, with the edges of the secondary damper and the primary damper being aligned to each other.

According to an embodiment, the modular switch comprises a moving contact bed adapted to sit and press the secondary damper, through a snap fitment with the bottom housing by two snaps at the top and bottom respectively.

According to an embodiment, the secondary damper is adapted to absorb the vibration of the fixed metal contacts as said secondary damper is sandwiched between the fixed contacts and the moving contact bed.

According to an embodiment, the modular switch comprises a moving contact operably placed on moving contact bed, so as to engage an actuator assembly.

According to an embodiment, the actuator assembly comprises a spring knob assembly placed from the top of the modular switch, said spring knob assembly comprising: a spring inserted in an actuator through a transition fit; a spring head inserted in the spring, through a transition fit, wherein the tip of the spring head is adapted to be placed on the moving contact.

According to an embodiment, the secondary damper is adapted to attenuate the sound waves created during switch off operation, wherein during a switch off operation, the moving contact is adapted to return to its initial position in fraction of a second and strike the moving contact bed at the centre with an impact again creating a noise.

According to an embodiment, the actuator is adapted to be pressed till the spring is compressed and the actuator is connected with the bottom housing through a plurality of hinge joints on the left side and the right side.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 illustrates a simple modular one-way switch.
Figure 2 illustrates inside assembly of switch after removing the plastic actuator.
Figure 3 illustrates a damper for fixed contact which is having two slots for two fixed metal contacts.
Figure 4 illustrates a moving contact damper which is having four legs which eventually absorbs the momentum of moving contact during off operation of a switch, according to an embodiment of the present invention.
Figure 5 illustrates a cross sectional view of a noiseless electrical modular switch showing all the component inside the assembly, according to an embodiment of the present invention.
Figure 6 illustrates an inside assembly of a normal mechanical switch when the actuator is removed and further shows how the metal contacts are directly press fitted in between the ribs of rear housing.
Figure 7 illustrates a primary damper of a noiseless electrical modular switch, according to an embodiment of the present invention.
Figure 8 illustrates a sub assembly damper of a noiseless electrical modular switch, according to an embodiment of the present invention.
Figure 9 illustrates the various components of a noiseless electrical modular switch with all the components exploded in the assembly order, according to an embodiment of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.

The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. Also, Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

The present disclosure will now be described more fully with reference to the accompanying drawings, in which various embodiments of the present disclosure are shown. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the various embodiments set forth herein, rather, these various embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the present disclosure. Furthermore, a detailed description of other parts will not be provided not to make the present disclosure unclear. Like reference numerals in the drawings refer to like elements throughout.

The subject invention lies in a noiseless electrical modular switch comprising a bottom housing (1) adapted to fit a sub-assembly damper, wherein the sub-assembly damper fitted within the bottom housing (1) comprises an assembly of a primary damper (2) and a plurality of fixed metal contacts (3, 4) adapted to fit inside said primary damper (2), such that the plurality of fixed metal contacts (3, 4) is in indirect contact with the bottom housing (1), so as to attenuate any sound wave generated due to any movement of the internal contacts of the modular switch.

The working principle of mechanical switches is conventional spring rocker mechanism. A conventional rocker switch consists of two metal contacts and one moving rocker which is spring loaded.

The rocker sits on one of the metal contacts and through an actuating lever it is brought in contact with the other metal contacts.

Since the rocker is loaded with spring, it is under a particular pressure. Turning the actuator gradually stretches the spring. When the mechanism passes over the center point, the spring energy is released and the spring, rather than the actuator, drives the contacts rapidly and forcibly to the closed position.

Similarly, when the actuator is turned off, the spring gradually compresses, comes at center point and then releases energy to break the contacts.

Figure 2 represents the internal components of the noiseless switch when actuator and bottom housing is removed. Figure 3 and figure 4 shows the primary and secondary damper respectively. Fig 5 represents a cross-sectional view of switch for better understanding of contacts and mechanism.

According to an embodiment of a noiseless electrical modular switch, as illustrated in Figure 5, it comprises a bottom housing (1) which accommodates a plurality of fixed metal contacts (3, 4), a moving contact bed (6) and a moving contact (7). A spring knob assembly is placed from the top with a spring (9) under initial compression and an actuator (10) hinged with the housing (1). Initially the metal contacts (3, 4) were held by the ribs inside housing and were in direct contact with it. The ribs are illustrated in Figure 6. As soon as the moving contact (7) strikes the fixed contact (3, 4), vibration and sound is generated. Since sound travels across solids easily in the form of compressions and rarefactions and its source is in direct contact of housing, so before any attenuation of waves it comes out in the environment as noise.

Therefore, to attenuate the waves at the source itself, the fixed metal contacts (3, 4) are first placed inside the primary damper, the primary damper being illustrated in Figure 7, and then this sub assembly damper as illustrated in Figure 8, is placed inside the housing. Now the contacts i.e. sound source is not in direct contact of housing and the waves generated attenuates before it travels out.

Moreover, during switch off operation, the moving contact (7) used to return to its initial position in fraction of a second and strike the moving contact bed (6) at the centre with an impact again creating a noise. Here again same principle of damping and decoupling of sound is applied and a secondary damper is attached at bottom of moving contact bed, the secondary damper being illustrated in Figure 4. This secondary damper not only absorbs the vibration of fixed contacts (3, 4) as it is sandwiched between fixed contacts (3, 4) and moving contact bed (6) but also attenuates the waves created during switch off operation.

The working principle of a switch is based on classic spring rocker theory, however the modular switch of the present invention achieves a silent switching operation by absorption of sound wave at the source itself and decoupling of it from the surroundings.

According to an embodiment, as illustrated in Figure 9, in the noiseless modular switch, a primary damper (2) is press fitted in the bottom housing (1) of the switch. Then fixed metal contacts (3,4) is press fitted in primary damper (2). Secondary damper (5) is then placed on primary damper aligning with the circular tip of primary damper. Moving contact bed (6) then sits and presses the secondary damper through snap fitment with bottom housing (1) by two snaps at top and bottom respectively. Moving contact (7) is then placed on moving contact bed (6). Spring (9) is inserted in actuator (10) through transition fit. Spring head (8) is inserted in spring (9), again through transition fit. Now the tip of spring head (8) is place on moving contact (7) and actuator (10) is pressed till the spring (9) is compressed and the actuator (10) is connected with bottom housing (1) through hinge joints on left and right side.

According to an embodiment, the modular switch has increased overall mass across the contacts unit keeping the volume constant thus achieving sound reduction according to the massing principle of sound absorption.

In addition, according to an embodiment the material selected for damping is a specific kind of thermoplastic elastomer having excellent damping characteristics along with heat and fire resistance.

In an embodiment, the noiseless modular switch The invention also enhances the life of switch as the primary damper acts as spring and provide proper contact pressure, which eliminates possibility of rebound, thus reduction in arching.

Some of the non-limiting advantages of the noiseless electrical modular switch are:
1. Easy adaptability to single pole double pole and two-way switch with minimum assembly effort.
2. Easy adaptability to different kind of mechanism be it toggle, rocker, cam operated or magnetically driven as it involves the housing of contacts only.
3. Prevents erosion of fixed contacts with time by absorbing any kind of vibration and providing cushioning during impact thus improving switch life.

Although a noiseless electrical modular switch has been described in language specific to structural features, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific methods or devices described herein. Rather, the specific features are disclosed as examples of implementations of a noiseless electrical modular switch.

Reference numerals:
Bottom Housing (1)
Primary Damper (2)
Fixed metal contact (3)
fixed metal contact (4)
Secondary damper (5)
Moving contact bed (6)
Moving contact (7)
Spring head (8)
Spring (9)
Actuator (10)
, Claims:
1. A noiseless electrical modular switch comprising:
a bottom housing (1) adapted to fit a sub-assembly damper, wherein the sub-assembly damper fitted within the bottom housing (1) comprises an assembly of a primary damper (2) and a plurality of fixed metal contacts (3, 4) adapted to fit inside said primary damper (2), such that the plurality of fixed metal contacts (3, 4) is in indirect contact with the bottom housing (1), so as to attenuate any sound wave generated due to any movement of the internal contacts of the modular switch.

2. The modular switch as claimed in claim 1, wherein the modular switch comprises: a secondary damper (5) adapted to fit with the sub-assembly damper, with the edges of the secondary damper (5) and the primary damper (2) being aligned to each other.

3. The modular switch as claimed in claim 1, wherein the modular switch comprises a moving contact bed (6) adapted to sit and press the secondary damper (5), through a snap fitment with the bottom housing (1) by two snaps at the top and bottom respectively.

4. The modular switch as claimed in claim 1, wherein the secondary damper (5) is adapted to absorb the vibration of the fixed metal contacts (3, 4) as said secondary damper (5) is sandwiched between the fixed contacts (3, 4) and the moving contact bed (6).

5. The modular switch as claimed in claim 1, wherein the modular switch comprises a moving contact (7) operably placed on moving contact bed (6), so as to engage an actuator assembly.

6. The modular switch as claimed in claim 1, wherein the actuator assembly comprises a spring knob assembly placed from the top of the modular switch, said spring knob assembly comprising:
a spring (9) inserted in an actuator (10) through a transition fit;
a spring head (8) inserted in the spring (9), through a transition fit,
wherein the tip of the spring head (8) is adapted to be placed on the moving contact (7).

7. The modular switch as claimed in claim 1, wherein the actuator (10) is adapted to be pressed till the spring (9) is compressed and the actuator (10) is connected with the bottom housing (1) through a plurality of hinge joints on the left side and the right side.

8. The modular switch as claimed in claim 1, wherein the secondary damper (5) is adapted to attenuate the sound waves created during switch off operation, wherein during a switch off operation, the moving contact (7) is adapted to return to its initial position in fraction of a second and strike the moving contact bed (6) at the centre with an impact again creating a noise.