The present invention generally relates to a push type switch and more particularly to a push
button switch for incorporation in an automotive vehicle.
BACKGROUND TO THE INVENTION:
In vehicles, it is a common practice to include multiple electrical circuits providing different
types of functions, for example an ignition function, an engine kill function, a horn function,
a blinker (turn indicator) function, a head light on function, a low beam function, a high beam
function, a pass function, a brake light function, a door open indication function and the like.
Depending upon the type of function, switches of different construction are incorporated in
the vehicle. One of the switches which is incorporated in the vehicle is a push-type switch.
The push type switch is incorporated for realizing functions such as ignition function, engine
kill function, horn function, brake light function and door open indication function and the
like.
More particularly, it is a common practice to include a brake light which is in electrical
connection with an electrical source through one or more switches. For example, in a
motorcycle, a scooter and the like, the brake light is in electrical connection with an electrical
source via a parallel combination of a front brake light switch and a rear brake light switch.
The front brake light switch is activated by a hand operated brake lever and the rear brake
light switch is activated by a foot operated brake pedal, and when a user applies pressure to
either the hand operated brake lever or foot operated brake pedal, a respective switch will
close to illuminate the brake light. In a car the brake light may be in electrical connection
with an electrical source via a parallel combination of brake light switch and a parking brake
switch. When the user actuates the parking brake lever or the brake lever pedal, a respective
switch will close to illuminate the brake light.
An external view of a most commonly available push-button type switch 100 is illustrated in
figure 1. The push button switch illustrated in figure 1 is extensively used in two wheeled
vehicles as the front brake light switch. The switch is located on the handle bar so as to cooperate
with the hand operated brake lever. When the hand operated brake lever is in a nonactuated
state, the front brake light switch is depressed by the brake lever, the circuit is open
and the brake light is therefore in the OFF state. On the other hand, when the brake lever is
actuated, the front brake light switch is released and the circuit is closed and the brake light is
therefore in the ON state. It is however, feasible that the push-button type switch as
2
illustrated in figure 1 can be used for providing other functions such as a rear brake switch, a
door switch etc. in a vehicle.
The push button type switch 100 as illustrated in figure 1 comprises a plunger 105 which
receives an actuating force. For example, if the push button switch is used as a front brake
switch, the plunger co-operates with the hand operated brake lever (not illustrated) and
receives the actuating force. On the other hand, if the push button type switch is used as a
door open indicator switch in car, the plunger 105 co-operates with the surface of the door
and receives the actuating force. The switch 100 further includes a pair of external contact
members 110 and 115 which are disposed on a lateral surface of a housing 120.
Now referring to figure 2, which is a part sectional view of the push button switch as
illustrated in figure 1, it can be seen that the housing 120 defines a through-hole 205 for
receiving the plunger 105. The plunger 105 comprises of a first end 210 and a second end 215
that traverses through the housing 120 and into an interior portion 220 of the housing. In the
interior portion 220, a moving contact member 225 is disposed, which is in contact with the
second end 215 of the plunger 105. In the interior portion 220 a fixed contact member 230 is
further disposed. The moving contact element 225 is in electrical connection with the external
contact member 110 and the fixed contact element 230 is in electrical connection with the
external contact member 115. The moving contact element 225 can be selectively brought in
contact with the fixed contact member 230 or can be held at a place so as to be physically
separate from the fixed contact, based on an extent of traversal of the plunger 105 into the
housing 120. In case a larger portion of the plunger 105 traverses into the interior portion 220
of the housing 120, the moving contact member 225 is physically separated from the fixed
contact member 230. On the other hand, when a lesser portion of the plunger 105 traverses
into the interior portion 220 of the housing 120, the moving contact member 225 makes
contact with the fixed contact member 230.
The moving contact member 225 further comprises a spring member 235 and a contact
member 240, wherein the spring member is in contact with the second end 215 of the plunger
105. In the absence of an external force on the plunger, the spring member urges the contact
member 240 towards the fixed contact 230 (to make contact) and also exerts force upon the
plunger 105 such that a lesser portion of the plunger 105 traverses into the interior portion
220 of the housing 120.
3
It has been observed that the aforesaid switch fails predominantly because of deterioration of
the contacts (i.e. the moving contact and/or the fixed contacts). It has been felt that the
deterioration of the contacts is predominantly because of ingress of elements such as air,
moisture or dust into the interior portion of the housing. It has been further observed that an
ingress path is available between the through-hole 205 provided in the housing and the
plunger 105 and through said ingress path elements such as air, moisture or dust could enter
into the interior portion of the housing and can cause damage to the contacts. Thus, to extend
the life of the switch, a grommet 245 has been suggested to be placed such that the grommet
245 surrounds the plunger and the space between the plunger and the through-hole 205
provided in the housing 120.
While with the provisioning of the grommet an extent of deterioration of the contacts (i.e. the
moving contact and/or the fixed contacts) has reduced, it has been observed that there is still
significant amount of deterioration of the contacts.
It has been further observed that placing the grommet 245 so as to surround the plunger and
the space between the plunger and the through hole 205 is a tedious and cost intensive
process. Conventionally, the plunger is provided with an aperture 250 proximate to the first
end 210 and a first end 255 of the grommet 245 is held in the aperture. The second end 260 of
the grommet 245 is then placed around the through-hole 205 of the housing 120 and securely
held thereto. For the purposes of securely holding the second end 260 of the grommet 245
either an additional part such as a locking ring is used or alternatively an additional process
step such as heat stacking is used. Figure 2 shows the outcome when heat stacking process is
used for securely holding the second end 260 of the grommet 245 around the through-hole
205 of the housing 120.
However, as mentioned above, because of the fact that the placement of grommet around the
ingress path has not completely removed the problem of deterioration of the contacts, there is
a need to provide a construction that eliminates a substantial amount of problem thus faced (it
being well understood that the problem of deterioration of the contact cannot be completely
isolated).
On a separate note, there is a need to provide a construction wherein a grommet can be
securely placed so as to surround the plunger and the space between the plunger and the
through-hole 205 in a cost effective manner.
4
SUMMARY OF THE INVENTION:
This summary is provided to introduce a selection of concepts in a simplified form that are
further described below in the detailed description. This summary is not intended to identify
key or essential features of the claimed subject matter, nor is it intended to be used as an aid
in determining the scope of the claimed subject matter.
In one embodiment of the invention, there is provided a push type switch that includes a
housing for accommodating a movable contact element and a fixed contact element. An
energy absorber is positioned between an internal surface of the housing and the fixed contact
element for absorbing kinetic energy transferred by the moving contact element to the fixed
contact element during a contact making action.
In another embodiment of the invention, there is provided a push type switch that includes
housing for accommodating a movable contact element and a fixed contact element. The
housing is provided with a through-hole and a plunger member is provided such that the same
traverses via the through-hole to act upon the movable contact element. A grommet is
positioned such that the same surrounds the plunger and an ingress path between the plunger
and the through hole. An external surface of the housing surrounding the through hole is
provided with a mechanism providing a snap-fit between one end of the grommet and the
external surface of the housing.
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 figures. It is appreciated that these figures depict only
typical embodiments of the invention and are therefore not to be considered limiting of its
scope.
BRIEF DESCRIPTION OF THE FIGURES:
The invention will be described and explained with additional specificity and detail with the
accompanying figures in which:
Figure 1 is an example representation of a push type switch, in accordance with prior art;
Figure 2 illustrates a part sectional view of the push type switch of Figure 1;
Figure 3 illustrates a sectional view of a push type switch, in accordance with an
embodiment;
5
Figure 4 illustrates an exploded view of the push type switch illustrated in Figure 3;
Figure 5 illustrates a sectional view of a push type switch, in accordance with another
embodiment;
Figure 6 illustrates an exploded view of the push type switch illustrated in Figure 5;
Figure 7 illustrates a sectional view of a push type switch, in accordance with yet another
embodiment;
Figure 8 illustrates an exploded view of the push type switch illustrated in Figure 7;
Figure 9 illustrates an exploded view of a push type switch, in accordance with still another
embodiment;
Figure 10 is a cross-sectional view of the push type switch shown in Figure 9 specifically
illustrating the snap fit mechanism for securely holding the grommet around the through-hole
in accordance with an embodiment;
Figure 11 illustrates an exploded view of a push type switch, in accordance with further
embodiment;
Figure 12 illustrates a part sectional view of the housing and the cover illustrating a taper
locking mechanism, in accordance with an embodiment;
Figure 13 illustrates a general view of the push-type switch shown in Figure 12 in an open (or
non-conductive) state, in accordance with an embodiment; and
Figure 14 illustrates a general view of the push-type switch shown in Figure 12 in a closed
(or conductive) state, in accordance with an embodiment.
Further, skilled artisans will appreciate that elements in the figures are illustrated for
simplicity and may not have been necessarily been drawn to scale. Furthermore, in terms of
the construction of the device, one or more components of the device may have been
represented in the figures by conventional symbols, and the figures may show only those
specific details that are pertinent to understanding the embodiments of the present invention
so as not to obscure the figures with details that will be readily apparent to those of ordinary
skill in the art having benefit of the description herein.
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 figures 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
6
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 exemplary and explanatory of the invention and are not
intended to be restrictive thereof.
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 invention. 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
non-exclusive 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 sub-systems 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.
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.
Embodiments of the present invention will be described below in detail with reference to the
accompanying figures.
Referring to figures 3 and 4, which are sectional view and an exploded view, respectively, a
push type switch 300 in accordance with an embodiment comprises a housing 305 for
accommodating a moving contact element 310 and a fixed contact element 315. The push
type switch further comprises an energy absorber 320 positioned between an internal surface
7
of the housing 305 and the fixed contact element 315 for absorbing kinetic energy transferred
by the moving contact element 310 to the fixed contact element 315 during a contact making
action.
The push type switch further comprises a plunger element 325 for transferring an actuating
force to the moving contact element 310. The housing 305 is provided with a through-hole
330 and the plunger 325 traverses through the through-hole 330 for actuating the moving
contact element 310.
In an embodiment of the present invention, the fixed contact element 315 is in electrical
contact with an external contact member 335. In another embodiment of the present
invention, the moving contact element 310 is in electrical contact with an external contact
member 340. In a preferred aspect of the invention, the moving contact element 310
comprises a spring member 345 and a contact member 350 which is mechanically and
electrically connected to the spring member 345. The spring member 345 is in operational
inter-relationship with the plunger 325.
The push type switch further comprises a casing 355 for closing the housing 305. In a
preferred embodiment of the present invention, the casing and the housing are provided with
a taper locking mechanism to provide a good sealing from environmental factors.
In a preferred aspect of the invention, the energy absorber 320 is a compression spring. In a
furthermore preferred embodiment of the invention, an internal surface of the housing 305 is
provided with a well-shaped structure 360 for securely accommodating the energy absorber
320.
In a preferred aspect of the invention, the plunger is provided with a snap lock for securely
holding the plunger in the housing and does not allow the plunger to come out from the
housing in normally closed condition of push type switch.
Now referring to figures 5 and 6, there is illustrated a sectional view and an exploded view,
respectively, of a push type switch 500 in accordance with another embodiment. The
construction of the push type switch 500 is substantially similar to that of the push type
switch 300 illustrated in figures 3 and 4 and hence a detailed explanation of the common
parts (parts common to the switch 300 and switch 500) is not being presented. While in the
embodiment illustrated in figures 3 and 4, an ingress path between the through-hole 330 as
8
provided in the housing 305 and the plunger element 325 was left un-sealed, in the push type
switch embodiment illustrated in figures 5 and 6, a sealing member 505 is provided in the
vicinity of the through-hole 330 to provide a flush-fit arrangement with the plunger element
325. In particular, an internal surface 510 of the housing 305 is provided with an aperture 515
in the vicinity of the through-hole 330 to accommodate a sealing member 505 and thereby
provide a prohibit ingress of water, air or moisture or solid particles (such as dust) into the
interior of the housing via the ingress path. Similar to embodiment illustrated in figure 3, the
plunger is provided with a snap lock for securely holding the plunger in the housing and does
not allow the plunger to come out from the housing in normally closed condition of push type
switch.
Now referring to figures 7 and 8, there is illustrated a sectional view and an exploded view,
respectively, of a push type switch 700 in accordance with yet another embodiment. The
construction of the push type switch 700 is substantially similar to that of the push type
switch 300 illustrated in figures 3 and 4 and hence a detailed explanation of the common
parts (parts common to the switch 300 and switch 500) is not being presented. In this
embodiment, a grommet 705 adapted to prevent ingress of water, air, moisture or dust into
the interior portion of the housing is provided. In particular, the grommet surrounds the
plunger 325 and a space between the plunger and the through-hole 330 provided in the
housing. The plunger is provided with an aperture 710 proximate to a first end 715 and a first
end 720 of the grommet 705 is held by the aperture 710 while a second end 725 of the
grommet 705 is placed around the through-hole of the housing and securely held thereto. In
particular, an external surface 730 of the housing 305 surrounding the through-hole 330 is
provided with a relieved groove 735 for receiving a second end 725 of the grommet 705.
Similar to what has been illustrated in figures 3 and 5, the plunger is provided with a snap
lock for securely holding the plunger in the housing and does not allow the plunger to come
out from the housing in normally closed condition of push type switch.
It has been surprisingly found that because of the provision of the energy absorber there has
been a substantial decrease in the amount of deterioration of the contacts. It can be observed
that the energy absorber which is preferably in the form of a compression spring has been
accommodated in the well-shaped structure 360 which is provided on the internal surface of
the housing 305. Particularly, the well-shaped structure is positioned on the internal surface
of the housing which is behind the fixed contact element 315. Placing the well-shaped
9
structure on the internal surface of the housing which is behind the fixed contact element and
locating the compression spring inside the well-shaped structure helps in packaging the
switch in a substantially small envelope size.
Now coming to the aspect of providing a cost effective and user friendly mechanism for
attaining sealing of the ingress path between the through-hole 330 as provided in the housing
305 and the plunger element 325, it can be observed that the first sealing construction as
described with reference to figures 5 to 6 or the second sealing construction as described with
reference to figures 7 and 8 are cost effective and user friendly.
Additionally a third sealing construction has been provided which is illustrated in figure 9. In
the embodiment illustrated in figure 9, the energy absorber has been purposefully deleted
from the push type switch to emphasize upon the fact that the advantages as derived by the
illustrated sealing construction are independent of the advantages as provided by the
inclusion of the energy absorber.
The push type switch 900 as illustrated in figure 9 comprises a housing 305 for
accommodating a moving contact element 310 and a fixed contact element 315. The push
type switch further comprises a plunger element 325 for transferring an actuating force to the
moving contact element 310. The housing 305 is provided with a through-hole 330 and the
plunger 325 traverses through the through-hole 330 for actuating the moving contact element
310.
In an embodiment of the present invention, the fixed contact element 315 is in electrical
contact with an external contact member 335 and the moving contact element 310 is in
electrical contact with an external contact member 340. Similar to the switch illustrated in
figure 3, the moving contact element 310 comprises a spring member 345 and a contact
member 350 which is mechanically and electrically connected to the spring member 345. The
spring member 345 is in operational inter-relationship with the plunger 325. The push type
switch further comprises a casing 355 for closing the housing 305.
Similar to the switch 700 illustrated in figures 7 and 8, the switch 900 also includes a
grommet 905 adapted to prevent ingress of water, air, moisture or dust into the interior
portion of the housing is provided. In particular, the grommet 905 surrounds the plunger 325
and a space between the plunger and the through-hole 330 provided in the housing. The
10
plunger is provided with an aperture 910 proximate to a first end 915 and a first end 920 of
the grommet 905 is held by the aperture 710 while a second end 925 of the grommet 905 is
placed around the through-hole of the housing and securely held thereto.
It must be noted that the construction of the grommet 905 as illustrated in figure 9 is different
from the construction of the grommet 705 as illustrated in figures 7 and 8, the difference
being particularly in terms of the construction of the second end 925 of the grommet 905.
While in the grommet 705 illustrated in figures 7 and 8, the second end 725 is inwardly
protruding, the second end 925 of the grommet 905 illustrated in figure 9 is in the form of an
outwardly protruding flange member. As used herein the ‘flange’ or “flange member” is a
circular protrusion at the one end of the grommet that is capable of being used as an
attachment to another part or object.
The external surface 930 of the housing 305 surrounding the through-hole 330 is provided
with a mechanism 935 providing a snap-fit between the second end 925 of the grommet 905
and the external surface 930 of the housing 305.
Referring to figure 10, which illustrates a partial cross sectional view of the switch 900, the
mechanism 935 includes a first vertical wall member 1005 located close to the through-hole
330, a horizontal wall member 1010 (which may be integral to the external surface of the
housing) which extends outwardly from the first vertical wall member 1005 and a second
vertical wall member 1015 that surrounds the first vertical wall member. The first vertical
wall member 1005, the horizontal wall member 1010 and the second vertical wall member
1015 together form a cavity adapted to receive the second end 925 of the grommet 905. An
inner surface of the second vertical wall member 1015 facing the first vertical wall member
1005 is provided with a ridge structure 1120 that interlocks with a groove structure 1025
provided on the second end 925 of the grommet 905. In this embodiment, the snap lock as
provided in the plunger can also be seen and the snap lock securely holds the plunger in the
housing and does not allow the plunger to come out from the housing in normally closed
condition of push type switch.
Compared to the prior art mechanism wherein the second end of the grommet is held securely
to the external surface of the housing using a separate locking ring, the first embodiment
illustrated in figures 5-6, the second embodiment illustrated in figures 7-8 and the third
11
embodiment illustrated in figures 9-10 each avoid use of additional parts and thus can result
in cost saving.
In comparison to the prior art mechanism wherein the second end of the grommet is held
securely to the external surface of the housing by heat stacking process, the first embodiment
illustrated in figures 5-6, the second embodiment illustrated in figures 7-8 and the third
embodiment illustrated in figures 9-10 each avoid use of such complicated process, because
of which cost saving, time saving and ease of handling can be expected.
As mentioned in the background section, the push type switch as constructed in accordance
with the teachings of the present invention can find beneficial uses in automotive vehicles.
Particularly, switch can be used in vehicles such as a car, a pit bike, a monkey bike, a scooter,
and the like. In a preferred aspect of the invention, the push type switch can be used for
deriving functions in a vehicle which are based on push-to-break. Such functions can include
brake illumination, door open detection etc.
In the following paragraphs, a push type switch constructed by way of example in accordance
with the teachings of the invention is illustrated and described in detail. It must be however
understood that the following description is provided merely for the purposes of illustration
and is not intended to be limiting the scope of the claims.
Example:
Referring to figure 11 and 12, the push type switch 1100 includes a housing 1105
accommodating a moving contact element 1110 and a fixed contact element 1115. A
compression spring 1120 is positioned between an internal surface of the housing 1105 and
the fixed contact element 1115. Particularly, an internal surface of the housing 1105 is
provided with a well-shaped structure 1160 for securely accommodating the compression
spring 1120. In order to keep the envelope size of the switch small, the well-shaped structure
is positioned on the internal surface of the housing which is behind the fixed contact element
1115.
A plunger element 1125 transfers an actuating force to the moving contact element 1110. In
an example, the plunger element is made of a polyoxymethylene (POM) material. The
housing 1105 is provided with a through-hole 1130 and the plunger 1125 traverses through
the through-hole 1130 for actuating the moving contact element 1110. The fixed contact
12
element 1115 which may be a contact rivet of cylindrical shape made of electrolytic tough
pitch (ETP) copper material is in electrical contact with an external contact member 1135 and
the moving contact element 1110 is in electrical contact with an external contact member
1140. The moving contact element 1110 comprises a spring member 1145 which may be
made of spring steel material and a contact member 1150 which is mechanically and
electrically connected to the spring member 1145. The contact member 1150 may be made of
ETP copper material. The spring member 1145 is in operational inter-relationship with the
plunger 1125. A casing 1155 is used for closing the housing 1105. The casing may be made
of a polyvinyl chloride (PVC) material or a combination of ethylene propylene diene
terpolymer and acrylonitrile butadiene styrene (EPDM+ABS).
The switch 1100 further includes a grommet 1165 adapted to prevent ingress of water, air,
moisture or dust into the interior portion of the housing is provided. In particular, the
grommet 1165 surrounds the plunger 1125 and a space between the plunger and the throughhole
1130 provided in the housing. The plunger is provided with an aperture 1170 proximate
to a first end 1175 and a first end 1180 of the grommet 1165 is held by the aperture 1170.
A second end 1185 of the grommet 1165 is in the form of an outwardly protruding flange
member. An external surface 1190 of the housing 1105 surrounding the through-hole 1130 is
provided with a mechanism 1195 providing a snap-fit between the second end 1185 of the
grommet 1165 and the external surface 1190 of the housing 1105. The structure of the snap
fit mechanism 1195 can be as illustrated in figure 10.
In an example, the plunger element conforms to an ingress protection (IP) rating of IP67
which certifies that the plunger is totally protected against dust and is protected against effect
of immersion between 15 centimeters and 1 meter.
Referring to figure 12, in a preferred embodiment of the present invention, the casing and the
housing are provided with a taper locking mechanism. Particularly, an edge of the casing
1155 that is in abutting relation with the housing 1105 comprises a first projecting wall 1205
and a second projecting wall 1210 that are spaced apart from each other and which define a
cavity there-between. An edge of the housing that is in abutting relation with the casing
comprises a wall member 1215 which is dimensioned so as to fit into the cavity defined by
the first and second projecting walls of the housing. In a preferred aspect of the invention the
wall member 1215 is provided with a tapered surface 1220. The second projecting wall 1210
13
is also provided with a tapered surface 1225 so as to co-operate with the tapered surface 1220
s provided on the wall member 1215 and define a locking arrangement.
Now referring to figure 13 an internal view of the push type switch in an open (or nonconductive)
state is illustrated. From the figure, it can be clearly observed that the because of
the actuation of the plunger element, the moving contact element is held in a distanced
relationship compared to the fixed contact.
Now referring to figure 14, an internal view of the the push type switch in an closed (or
conductive) state is illustrated. From the figure, it can be clearly observed that once the
actuating force ceases to act upon the plunger, the moving contact element automatically
comes in contact with the fixed contact. Also, in this state the plunger can be marginally
pushed backward so that a lesser extent of the plunger traverses into the casing.
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 forgoing 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. Moreover, the actions of any flow diagram need not be
implemented in the order shown; nor do all of the acts necessarily need to be performed.
Also, those acts that are not dependent on other acts may be performed in parallel with the
other acts. 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
14
We Claim:
1. A push type switch, comprising:
a housing for accommodating a moving contact element and a fixed contact element;
an energy absorber positioned between an internal surface of the housing and the
fixed contact element for absorbing kinetic energy transferred by the moving contact
element to the fixed contact element during a contact making action.
2. The push type switch as claimed in claim 1, further comprising a plunger element for
transferring an actuating force to the moving contact element.
3. The push type switch as claimed in claim 1, wherein the housing is further provided
with a through hole and the plunger traverses through the through-hole for actuating
the moving contact element.
4. The push type switch as claimed in claim 1, wherein the fixed contact element is in
electrical contact with an external contact member.
5. The push type switch as claimed in claim 1, wherein the moving contact element
comprises a spring member that is in electrical contact with an external contact
member and a contact member which is mechanically and electrically connected to
the spring member.
6. The push type switch as claimed in claim 5, wherein the spring member is in
operational inter-relationship with the plunger.
7. The push type switch as claimed in claim 1, further comprising a grommet for
preventing ingress of air, moisture or dust into an interior portion of the housing.
8. The push type switch as claimed in any of the preceding claims, wherein the grommet
surrounds the plunger and a space between the plunger and the through-hole provided
in the housing.
9. The push type switch as claimed in claim 8, wherein the plunger is provided with an
aperture proximate to a first end and a first end of the grommet is held by the aperture
and a second end of the grommet is placed around the through-hole of the housing
and securely held thereto.
15
10. The push type switch as claimed in claim 9, wherein an external surface of the
housing surrounding the through-hole is provided with a relieved groove for receiving
a second end of the grommet.
11. The push type switch as claimed in claim 9, wherein an external surface of the
housing surrounding the through-hole is provided a mechanism providing a snap-fit
between the second end of the grommet and the external surface of the housing.
12. The push type switch as claimed in claim 1, wherein a sealing member is provided in
the vicinity of the through-hole to provide a flush-fit with the plunger.
13. The push type switch as claimed in claim 1, wherein an internal surface of the housing
is provided with an aperture in the vicinity of the through-hole to sealing member and
provide a flush-fit with the plunger.
14. The push type switch as claimed in claim 1, further comprising a casing for closing
the housing.
15. The push type switch as claimed in claim 1, wherein an internal surface of the housing
is provided with a well-shaped structure for accommodating the energy absorber.
16. The push type switch as claimed in claim 1, wherein the energy absorber is a
compression spring.
17. The push type switch as claimed in claim 1, wherein the plunger is provided with a
snap lock for securely holding the plunger in the housing and does not allow the
plunger to come out from the housing in normally closed condition of push type
switch.
18. A push-type switch, comprising:
a housing for accommodating a moving contact element and a fixed contact element,
the housing defining a through-hole;
a plunger traversing through the through-hole for actuating the moving contact
element; and
a grommet surrounding the plunger and an ingress path between the plunger and the
through hole; and
16
external surface of the housing surrounding the through hole is provided with a
mechanism providing a snap-fit between one end of the grommet and the external
surface of the housing.
19. The push type switch as claimed in claim 18, wherein the plunger defines a first end
adapted for receiving an actuating force and a second adapted to transfer said
actuating force to the moving contact element.
20. The push type switch as claimed in claim 18, wherein the fixed contact element is in
electrical contact with an external contact member.
21. The push type switch as claimed in claim 18, wherein the moving contact element
comprises a spring member that is in electrical contact with an external contact
member and a contact member which is mechanically and electrically connected to
the spring member.
22. The push type switch as claimed in claim 21, wherein the spring member is in
operational inter-relationship with the plunger.
23. The push type switch as claimed in claim 19, wherein the plunger is provided with an
aperture proximate to the first end and a first end of the grommet is held by the
aperture.
24. The push type switch as claimed in claim 18, further comprising a casing for closing
the housing.
25. The push type switch as claimed in claim 18, wherein an energy absorber is
positioned between an internal surface of the housing and the fixed contact element
for absorbing kinetic energy transferred by the moving contact element to the fixed
contact element during a contact making action.
26. The push type switch as claimed in claim 25, wherein the internal surface of the
housing is provided with a well-shaped structure for accommodating the energy
absorber.
27. The push type switch as claimed in claim 25, wherein the energy absorber is a
compression spring.
28. The push type switch as claimed in claim 18, wherein the plunger is provided with a
snap lock for securely holding the plunger in the housing and does not allow the
plunger to come out from the housing in normally closed condition of push type
switch.