TECHNICAL FIELD:
The present disclosure relates to a switch assembly for vehicle. Particularly, the
present disclosure relates to a switch assembly also known as door lamp-switch for
providing input/output directly to the main cabin lamp in a vehicle which activates/
deactivates during opening/ closing of any of the doors of the vehicle.
BACKGROUND:
Switches for activating/deactivating cabin lamp are generally known as door lampswitch.
The said switches are activated/deactivated while opening and closing of
the door. The door lamp switches are commonly used part in vehicle and
configured to serve the purpose of switching ON/OFF the main cabin lamp upon
opening/closing of the vehicle’s door. It also helps the passengers to check
whether the doors are properly closed or not and also provides necessary light in
the vehicle cabin. The door-lamp switch activates the cabin lamp at release of
force/load by opening of the door over it and deactivates the cabin lamp when the
force/load is applied on it.
Current requirement for the circuit to perform the above-mentioned task of doorlamp
switch is normally 3Ampere and the circuit is directly connected to battery of
the vehicle. Due to the presence of current in the circuit, an arcing is generally
develops between the contacts of the switch, every time the switch performs its
function. Due to the arcing between the contacts, grease which is applied on the
fixed contact forms powdered carbon. The constant use of the switch produces
enough amount of carbon between the fixed and moving contacts that it starts
forming insulating layers on top of the terminal/fixed contact. Due to the formation
of insulation layer, the switch fails to operate. Figure 1 (a) and Figure 1 (b)
illustrates the switch assembly of the conventional switches. The movement of
moving contact (M) over the fixed contact (F) is seen from Figure 1 (a). In the
conventional switches a gap (A) is provided between the switches. Due to the jerk
3
motion of moving contact over fixed contact there is a possibility of increase in the
width of the gap(A) of the switch assembly as shown in figure 1(b). Due to
increase in the width of the gap (A) there is a possibility that the moving contact
(M) will dig into the gap (if wide enough) and get stuck in the gap thereby causing
failure to the switch.
Hence, in these circumstances there is a need to develop a switch which addresses
to the above-mentioned problem and increases the life cycles of the door-lamp
switches so that they can work continuously for longer period of time.
In other words, researchers are constantly trying to develop a user friendly and
technically advance door lamp switch for vehicle(s). More specifically, a door
lamp switch assembly that is user friendly, economical, can be operated with
minimal effort and has minimum air resistance/reaction force.
SUMMARY
The present disclosure relates to a interior switch assembly of an
automobile/vehicle. In the present disclosure the switch assembly provides an arc
gap in the form of slots that collect the waste carbon which is formed due to arcing
between the fixed and moving contact. The arc gap eliminates the carbon which is
formed on the top surface of the fixed contact and hence, increases the life cycle of
the switch. In the present door lamp switch, tip of the fixed contact is adapted to
allow more effective use of the gaps, due to a slightly early break point. Preferably,
the tip is formed so as to extend in the slot so that the extended tip ensure that the
carbon residues fall in front of the fixed contacts and waste carbon is thus collected
in the channel. In the present door-lamp switch, the moving contact is wider than
the arc gap to avoid the moving contact to slip into the arc gap causing any
hindrance in its motion.
4
BRIEF DESCRIPTION OF FIGURES
Figure 1(a)-1(b) illustrates the existing prior backdoor switch assembly.
Figure 2 and 3 illustrates the top and assembled view of the interior switch
assembly for vehicle
Figure 4 shows the exploded view of the interior switch assembly according to the
embodiment of the present disclosure.
Figure 5(a) illustrates the back view of the switch assembly according to the
embodiment of the present disclosure.
Figure 5 (b) is the detailed view of the Figure 4.
Figure 6 (a) - 6(c) illustrates the mounting condition of different components of the
switch assembly in accordance with the embodiment of the present disclosure.
Figures 7(a)-7(d) illustrate the moving contact in accordance with an embodiment
of the present disclosure.
Figure 8 illustrates a perspective sectional view of the switch assembly in
accordance with an embodiment of the present disclosure
Figures 9(a)-(c) and 10 (a)-(b), illustrates the movement of the plunger and the
moving contact at ON and OFF position
Figure 11 (a)-11(b) shows occurrence of arcing at the time of making of contact
between the moving contact and the fixed contact.
Figure 12 (a) illustrates the sectional view of the switch assembly along the axis
Z-Z shown in Figure 1.
Figure 12 (b) shows the detail view of the Figure 11(a)
5
Figure 13 illustrates circuit diagram for the switch according an embodiment of the
present disclosure
DETAILED DESCRIPTION OF THE PRESENT DISCLOSURE
While the invention is subject to various modifications and alternative forms,
specific embodiment thereof has been shown by way of example in the figures and
will be described below. It should be understood, however that it is not intended to
limit the invention to the particular forms disclosed, but on the contrary, the
invention is to cover all modifications, equivalents, and alternative falling within
the scope of the invention.
It is to be noted that a person skilled in the art can be motivated from the present
invention and can perform various modifications. However, such modifications
should be construed within the scope of the invention.
Accordingly, the drawings are showing only those specific details that are pertinent
to understanding the embodiments of the present invention so as not to obscure the
disclosure with details that will be readily apparent to those of ordinary skill in the
art having benefit of the description herein.
The terms “comprises”, “comprising”, or any other variations thereof, are intended
to cover a non-exclusive inclusion, such that an assembly, setup, system,
device that comprises a list of components does not include only those
components but may include other components not expressly listed or inherent
to such system or device or setup. In other words, one or more elements in the
system or apparatus or device proceeded by “comprises a” does not, without more
constraints, preclude the existence of other elements or additional elements in the
assembly or system or apparatus. The following paragraphs explain present
invention.
6
Accordingly, the main aim of the present disclosure is to provide an arc gap in the
form of slots, which collects the waste carbon formed due to arcing between the
fixed and moving contact.
Another aim of the present disclosure is to provide an extended tip of the fixed
contact which ensures that the waste carbon residues fall in front of the fixed
contact inside the channel/slots of the arc gap.
Yet another advantage of the present disclosure is to have s moving contact which
is wider than the arc gap so to avoid the moving contact to slip into the arc gap
causing any hindrance in its motion and avoiding jerk.
Accordingly the present disclosure provides a switch assembly for vehicle
comprising a housing body having, an open end and a closed end, the open end of
the housing body being covered by a back cover, and the closed end of the body is
provided with an opening for extending a spring loaded plunger there through; the
plunger is disposed in the housing body and moveable in longitudinal direction in
the housing body; the plunger has a first end and a second end, the first end of the
plunger is disposed inside the body and the second end of the plunger is projected
outside the body and adapted to receive an actuating force; a moving contact being
mounted on first end of the plunger and moveable with the movement of the
plunger between the open end and the closed end of the housing body, the moving
contact comprises a rectangular base with plurality of arms extending from
peripheral edges of the base, a fixed contact comprising a pair of elongated
rectangular opposite ends, one end of the elongated fixed contact disposed in the
housing body and adapted to make contact with the arms of moving contact,
wherein the housing body comprises a pair of elongated slots on inner surface of
the housing body extending longitudinally between the open end and the closed
end of the housing body and in that a pair of fixed contact each having a tip
extending in the slot adapted to make contact with the arms of the moving contact.
7
In another embodiment of the present disclosure the width of the arms of the
moving contact is equal to or greater than the width of the slot.
In yet another embodiment of the present disclosure the first end of the plunger
comprises a mounting pin for mounting the moving contact.
In a further embodiment of the present disclosure a body insert is insert molded
acting as a mounting point for the switch of the vehicle.
In a further embodiment of the present disclosure one end of a spring is located at
the mounting pin and the other end of the spring is secured by the body cover.
In an alternate embodiment of the present disclosure a knob cover is provided with
a big circular dome, compresses and expands to toggle the switch.
In another embodiment of the present disclosure the extended tip is tapered from
both sides.
In one more embodiment of the present disclosure the depth of the arc gap is equal
to thickness of the fixed contact so that the arms of the moving contact slides over
insulating surface of the body.
The following paragraphs describe the present disclosure with reference to Figures
1 to 13 according to an embodiment of the present description.
The Inventor(s) have developed a switch which addresses at least one of the
limitations stated in the background of the present disclosure. The switch
comprises slots (herein after also referred as ‘arc gaps’). In the switch, arc is
developed due to connection between moving and fixed contact. The point where
arc is developed due to connection between moving and fixed contact is referred
herein as ‘make/break’. An arc gap may be defined as a channel provided in the
8
body of a switch in which any form of residue, generated during the arcing of the
power terminals (moving/fixed contacts), get collected so as to avoid any deposits
on the contacts (fixed and/or moving) which might hamper operation of the switch.
It acts like a dumpster for collecting the waste carbon.
In an embodiment of the present disclosure, the switch comprises at least two slots
(or arc gaps) and each of the fixed contacts partially extends into the slot. Depth of
the slot may be substantially equal to thickness of terminal/fixed contact so as to
provide an even surface for smooth movement of the moving contact over the fixed
contact surface.
In an embodiment, shape of ends of the fixed contact disposed in in the slots/arc
gap is formed so as to cause generation of arc slightly early thereby resulting in
more effective use of the gaps. In an embodiment, width of the moving contact is
sized to maintain its movement on the surface avoiding any bumps during
activation and provides a smooth movement of the moving contact.
Figure 2 and 3 illustrates the top and assembled view of the interior switch
assembly for vehicle (100). Figure 4 shows the exploded view of the interior
switch assembly (100) according to the embodiment of the present disclosure.
Figure 5(a) illustrates the back view of the switch assembly (100) according to the
embodiment of the present disclosure. Figure 5 (b) is the detailed view of the
Figure 5(a).
As shown in Figures 2- 4, the switch assembly for vehicle (100) comprising a knob
cover (1), a body insert (2), a housing body (3), a terminal/fixed contact (4), a
plunger (5), a moving contact (6), a spring (7), a back cover (8). The housing body
(3) of the switch assembly for vehicle (100) acts as a housing for accommodating
components of the switch. The housing body (3) is of a generally rectangular shape
structure having two ends, an open (3a) and a closed end (3b). The open end (3a)
of the housing body (3) may be covered by a back cover (8). The back cover (8) is
9
a protective cover which also restricts entry of any dust or water in the switch that
can hamper its function.
The closed end (3b) of the housing body (3) is provided with a first opening (3c)
for extending there through a plunger (5). The body insert (2) is secured to the
closed end (3b) of the housing body (3).
The body insert (2) may be insert molded with the housing body (3) and it acts as a
mounting panel for the switch on the vehicle. The body insert (2) also acts as an
earth terminal for the switch. The fixed contacts (4) are also connected with the
body insert (2). The body insert (2) is also provided with a second opening (2a) for
extending there through the plunger (5). As shown in Figure 4, a knob cover (1) is
provided for the purpose of protecting the switch assembly (100) and has a dome
shaped feature which is made up of soft plastic that compresses and expands to
toggle the plunger for operating the switch.
Figure 5(b) displays the position of the moving contact (6), the fixed contact (4)
and the housing body (3) of the switch.
Figure 6 (a) - 6(c) illustrates the mounting condition of different components of the
switch assembly in accordance with the embodiment of the present disclosure.
Referring to Figure 6(a)- 6(c), the plunger (5) has a first end (5a) and a second end
(5b). The first end (5a) is disposed inside the housing body (3) and the second end
(5b) is located outside the housing body (3) when the plunger (5) is assembled with
the housing body (3). The moving contact (6) is mounted on the first end of the
plunger (5). For this purpose, the plunger (5) may be provided with a mounting
pin (9) to cooperate with an opening provided in the moving contact (6) for
securing the moving contact (6) with the plunger (5).
10
Figures 7(a)-6(d) illustrate the moving contact (6) in accordance with an
embodiment of the present disclosure. Referring to Figures 7(a)-7(d), the moving
contact has a rectangular base (6a) with plurality of arms (6b) extending from
peripheral edges of the rectangular base (6a). The rectangular base (6a) and the
arms 6(b) of the moving contact (6) are made of conductive material suitable for
conducting electrical current.
The plunger (5) is mounted in the housing body (3) under a force of a spring (7). In
other words, the movement of plunger (5) is under a force of a spring (7). One end
of spring (7) may be located at the mounting pin (9) and the other end of the spring
(7) is secured by the back cover (8). As can be clearly understood, in use, when an
actuation force is applied on the second end of the plunger (5), the spring (7)
remain under compression and when the said actuation force is removed from
second end of the plunger (5) , the spring (7) tends to expand which pushes the
plunger (5) in a direction away from the back cover(8).
Referring to Figure 6 (b), the moving contact (6) is secured with the first end (5a)
of the plunger (5) and moves back and forth with the plunger (5). Upon movement
of the moving contact (6), the arm of the moving contact (6b) adapted to make
contact with the fixed contact (4) as shown in Figure 5(c) and thus, closes the
circuit for activation of the cabin lamp.
Figure 8 illustrates a perspective sectional view of the switch assembly in
accordance with an embodiment of the present disclosure. Referring to Figures
6(a) and 8, each of the fixed contacts (4) is an elongated fixed contact having
opposite ends. One of end of the elongated fixed contact (4) disposed in the
housing body (3) and adapted to make contact with the moving contact (6). The
said end of the elongated fixed contact (4) has an extended tip (4a) which is
tapered from both sides and the said extended tip (4a) is adapted make contact with
the moving contact (6).
11
As shown in Figure 8, the housing body (3) of the switch is provided with a pair of
elongated slots (10) at interior of the housing body (3). The extended tip (4a) of the
fixed contact (4) is disposed in each of the said slot (10). In an embodiment, the
elongated slots extend between the open end and the closed end of the housing
body.
Figures 9(a)-(c) and 10(a)-(b), illustrates the movement of the plunger (5) and the
moving contact (6) at ON and OFF position. Figures 9(a) and 10(a) illustrate OFF
position of the switch. Figures 9(c) and 10(b) illustrate ON position of the switch.
Figure 9(b) illustrates an intermediate position between the ON and OFF positions
of the switch. Referring to Figures 9(a)-(c) and 10(a)-(b), the moving contact (6) is
moveable between ON and OFF positions. The movement of the moving contact
(6) is effected by the plunger (5). As explained in the previous paragraphs, the
second end of the plunger (5) projects exterior to the housing body (3) and
available for the application of actuation force. When the door of the vehicle is
closed, an actuating force is applied on the second end of the plunger (5) in the
direction of arrow F1 which moves the first end of the plunger towards the back
cover against the force of the spring (7). In this position, the moving-contact lies
away from the fixed contact (4) defining the OFF position of the switch. It can be
clearly understood, the switch remain in OFF position when there is no connection
between the fixed contact (4) and the moving contact (6). When the door of the
vehicle is opened, the actuation force applied on the second end of the plunger (5)
gets released which causes the spring (7) to expand resulting in the releasing of the
applied force and spring (7) expands. Due to expansion of spring (7) an opposing
force F2 is applied on the first end of the plunger (5) resulting in movement of the
first end of the plunger (5) and the moving contact (6) towards the fixed contact
(4) from the OFF position (as shown in Figure 8(c)) resulting in making of contact
between the fixed contact (4) and the moving contact (6) (defining the ON
position) thereby closing the circuit to activate the cabin lamp. Figure 8 (b) depicts
that there is a connection between the moving contact (6) and the body insert (2)
which provides earthing to the switch assembly.
12
Figure 11(a) shows occurrence of arcing (11) at the time of making of contact
between the moving contact (6) and the fixed contact (4). As shown Figure 10 (a),
when the moving contact (6) moves towards the fixed contact (4), arcing (11)
develops as soon as there is a connection or contact between the moving and fixed
contacts (4). The said arcing (11) generates waste carbon (12) which gets
accumulated in the elongated slots or arc gaps (10) formed in the housing body (3)
as shown in Figure 6(b). Thus elongated slots work as arc gaps.
Referring to Figures 8 and 11(a)-(b), the arms of the moving contact (6) comes in
contact with the extended tip (4a) of the each of the fixed contact (4) disposed in
the arc gap or elongated slots (10). Therefore, the generated waste carbon (12) is
deposited inside the elongated slot (10).
Figure 12 (a) illustrates the sectional view of the switch assembly along the axis
Z-Z shown in Figure 2. Figure 12 (b) shows the detail view of the Figure 12(a)
showing smooth travel of moving contact over fixed contact and avoiding jerk
between housing body (2) and fixed contact(4). As shown in Figure 8, the depth of
the arc gap or elongated slot (10) is equal to thickness of the terminal/fixed contact
(4) so that the arms of the moving contact (6) slides over insulating surface of the
housing body (3) smoothly. The moving contact (6) is maintained on the fixed
contact (4) at all-time which provides a non-jerking motion over the fixed contact
(4) and avoids any jerks.
In the present disclosure, the width of moving contact (6) is equal to or greater than
the width of the arc gap, thereby avoiding jerk during the movement of the moving
contact.
As shown in Figure 11(b), the powdered carbon (12) is deposited in the arc gap
(10) thus eliminating/reducing chances of accumulation of the deposition of the
carbon on top surface of the fixed contact (4). Detail A of Figure 11 (b) shows an
13
enlarge view of the extended tip (4a) of the fixed contact (4). The advantage of
extended tip (4a) is to allow arcing to occur in front of fixed contact (4) which
ensures that the carbon residues (12) fall in front of fixed contact (4) i.e. in the arc
gap or elongated slots. (10). If any waste carbon (12) is moved with the moving
contact (6) while it is moving from ON position to OFF position, it is brought back
with the contact and dropped in the channel. Also along with this advantage, the
extended tip (4a) of the fixed contact (4) is tapered on its sides so that its contact
with the surrounding plastic of the insulator can be avoided significantly reducing
the amount of carbon produced in the first place. If the extended tip (4a) was of a
square shape extending up to the side walls of the channel, arcing (11) between the
contacts would have burnt the nearby plastic creating more carbon (12). Thus the
extended tip (4a) also allows a more effective use of the gaps, due to slightly early
break point or arcing (11).
Figure 13 illustrates circuit diagram for the switch according an embodiment of the
present disclosure. Referring to Figure 13, Point 3 is the main connection made
between the functioning of the switch. Point 2 is a reserve point provided for any
purpose (which requires similar current) as per customer specifications. Point 4 in
the circuit diagram is meant for earthing the switch, due to high current
requirement. The highlighted portion shows the connection between the points 2 &
3 with point 4. Point 4 is connected to Points 2 & 3 at all times to provide earthing
to both.
14
Some of the advantages of the present invention are as under:
The primary advantage of the present invention is to reduce the continuity
breakdown at any point during its life of 50,000 work cycles. The switch showed
no continuity breakdown during its life test which involves the switch to be tested
for 3 x 50,000 (proposed work cycles) i.e. 150,000 or until failure.
One more advantage of the present invention is smooth operation of switch as no
gaps are present in the moving path of the moving contact (6) until it reaches fixed
contact.
Another advantage of the present invention is to solve the problem of carbon
collection in between the contacts by modifying the switch effectively.
Yet another advantage of the present invention is the modification made on the tip
of the fixed contact. If the tip of the terminal was not extended as shown in Figure
5, the effectiveness of the arc gap would have been reduced significantly thereby
decreasing the life cycles. The carbon deposition would eventually settle between
the available spaces and cover the surface of fixed contact.
15
Equivalents:
The embodiments herein and the various features and advantageous details thereof
are explained with reference to the non-limiting embodiments in the description.
Descriptions of well-known components and processing techniques are omitted so
as to not unnecessarily obscure the embodiments herein. The examples used herein
are intended merely to facilitate an understanding of ways in which the
embodiments herein may be practiced and to further enable those of skill in the art
to practice the embodiments herein. Accordingly, the examples should not be
construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the
general nature of the embodiments herein that others can, by applying current
knowledge, readily modify and/or adapt for various applications such specific
embodiments without departing from the generic concept, and, therefore, such
adaptations and modifications should and are intended to be comprehended within
the meaning and range of equivalents of the disclosed embodiments. It is to be
understood that the phraseology or terminology employed herein is for the purpose
of description and not of limitation. Therefore, while the embodiments herein have
been described in terms of preferred embodiments, those skilled in the art will
recognize that the embodiments herein can be practiced with modification within
the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as
“comprises” or “comprising”, will be understood to imply the inclusion of a stated
element, integer or step, or group of elements, integers or steps, but not the
exclusion of any other element, integer or step, or group of elements, integers or
steps.
The use of the expression “at least” or “at least one” suggests the use of one or
more elements or ingredients or quantities, as the use may be in the embodiment of
the disclosure to achieve one or more of the desired objects or results.
16
Any discussion of documents, acts, materials, devices, articles and the like that has
been included in this specification is solely for the purpose of providing a context
for the disclosure. It is not to be taken as an admission that any or all of these
matters form a part of the prior art base or were common general knowledge in the
field relevant to the disclosure as it existed anywhere before the priority date of
this application.
The numerical values mentioned for the various physical parameters, dimensions
or quantities are only approximations and it is envisaged that the values
higher/lower than the numerical values assigned to the parameters, dimensions or
quantities fall within the scope of the disclosure, unless there is a statement in the
specification specific to the contrary.
While considerable emphasis has been placed herein on the particular features of
this disclosure, it will be appreciated that various modifications can be made, and
that many changes can be made in the preferred embodiments without departing
from the principles of the disclosure. These and other modifications in the nature
of the disclosure or the preferred embodiments will be apparent to those skilled in
the art from the disclosure herein, whereby it is to be distinctly understood that the
foregoing descriptive matter is to be interpreted merely as illustrative of the
disclosure and not as a limitation.
17
LIST OF REFERNCE NUMERALS
Interior Switch Assembly for
Vehicle
(100)
Knob cover (1)
Body insert (2)
Second opening of body insert (2a)
Housing body (3)
Open end of housing body (3a)
Closed end of housing body (3b)
First opening of the housing
body
(3c)
Terminal/Fixed contact (4)
Extended tip of the fixed
contact
(4a)
Plunger (5)
First end of the plunger (5a)
Second end of the plunger (5b)
Moving contact (6)
Rectangular base of moving
contact
(6a)
Arms of moving contact (6b)
Spring (7)
Back cover (8)
Mounting pin (9)
A pair of elongated slots (10)
Arcing (11)
Powdered/waste carbon (12)

WE CLAIM:
1. A switch assembly for vehicle comprising
a housing body (3) having, an open end and a closed end, the open
end of the housing body (3) being covered by a back cover, and the closed
end of the housing body (3) is provided with an opening for extending a
spring (7) loaded plunger (5) there through; the plunger (5) is disposed in
the housing body (3) and moveable in longitudinal direction in the housing
body (3); the plunger (5) has a first end and a second end, the first end of
the plunger (5) is disposed inside the housing body (3) and the second end
of the plunger (5) is projected outside the housing body (3) and adapted
to receive an actuating force; a moving contact (6) being mounted on first
end of the plunger (5) and moveable with the movement of the plunger (5)
between the open end and the closed end of the housing body (3), the
moving contact (6) comprises a rectangular base with plurality of arms
extending from peripheral edges of the base, a fixed contact (4) comprising
a pair of elongated rectangular opposite ends, one end of the elongated
fixed contact (4) disposed in the housing body (3) and adapted to make
contact with the arms of moving contact (6),
wherein the housing body (3) comprises a pair of elongated slots on
inner surface of the housing body (3) extending longitudinally between the
open end and the closed end of the housing body (3) and in that a pair of
fixed contact (4) each having a tip extending in the slot adapted to make
contact with the arms of the moving contact (6).
2. The switch assembly as claimed in claim 1, wherein, width of the arms of
the moving contact (6) is equal to or greater than the width of the slot.
20
3. The switch assembly as claimed in claim 1, wherein the first end of the
plunger (5) comprises a mounting pin (9) for mounting the moving contact
(6).
4. The switch assembly as claimed in claim 1 wherein a body insert (2) is
insert molded acting as a mounting point for the switch of the vehicle,
5. The switch assembly for vehicle as claimed in claim 1 wherein one end of
a spring (7) is located at the mounting pin (9) and the other end of the
spring (7) is secured by the body cover
6. The switch assembly for vehicle as claimed in claim 1 wherein a knob
cover provided with a big circular dome, compresses and expands to
toggle the switch;
7. The switch assembly for vehicle as claimed in claim 1 wherein the
extended tip is tapered from both sides
8. The switch assembly for vehicle as claimed in claim 1 wherein the depth
of the arc gap is equal to thickness of the fixed contact (4) so that the arms
of the moving contact (6) slides over insulating surface of the housing body
(3).