FIELD OF THE INVENTION

The present invention generally relates to control switch for two-wheeled/ three-wheeled vehicles. In particular, the present invention relates to a push type switch which prevents water, dust, oil, grease or other contaminants from damaging the working parts of the switch.

BACKGROUND OF THE INVENTION

Generally, two-wheeled/ three-wheeled vehicles perform various control functions required for smooth operation, safe driving and for giving indication to other riders while driving. These functions are governed by control buttons mounted over a control switch via battery in series. The control switch is typically mounted over a handle bar or a panel of vehicle. The functions which are used frequently such as Horn, dipper, turn indicator (blinker), pass etc are grouped over left hand side control switch. The functions which are used rarely such as Engine stop, Engine start, Head lamp ON-OFF, etc. are grouped over right hand side control switch of handle bar.

Usually, these control switches are exposed to harsh environmental conditions which may accelerate the deterioration of the active components of the switch, thereby jeopardizing the good operation of the switch.

Conventionally, Figure 1 illustrates a sectional view of a conventional push type switch. Figure 2 illustrates an exploded view of the conventional push type switch.
The conventional push type switch comprises a knob (201) with a solid plunger (202) insert molded to the knob (201). The plunger is made up of a brass material. At least one moving contact (203) is located around the plunger (202). The knob (201) with the plunger (202) and the moving contact (203) together form a knob assembly. The knob assembly is partially encased by a metal body (204). On an outer top surface of the metal body (204), a rubber grommet (205) is located. The grommet (205) is further covered by a plate (206).
Further, a small spring (207) and a large spring (208) are disposed inside the switch. The small spring (207) is located between the moving contact (203) and the plunger (202) and pushes the moving contact (203) downwards. The large spring (208) is disposed between the metal body (204) and the plunger (202) and pushes the knob (201) in an upward direction. To retain moving contact at a desired location, a circlip (209) is disposed beneath the moving contacts (203).
In addition, the switch comprises of a base (210). The base (210) is located beneath the plunger (202) accommodating two base terminals (211) and rivets (212). When the knob (201) is pressed, the moving contacts (203) touch the rivets (212) and form an electrical connection. The base (210) is provided with a nut (213) and a washer (214) on the bottom side to hold the body (204).

Figures 3-6 illustrate various embodiments of conventional push type switch.
Figure 3 illustrates the plunger (201) insert molded to the knob (202). Figure 4 illustrates the assembly (401) of plate (206) and the rubber grommet (205).The start symbol is pad printed on the plate (206). The plate (206) is mounted on the top of the rubber grommet (205). Figure 5 illustrates a perspective view of the metallic washer (214) assembled on the switch. Figure 6 illustrates the circlip (209) located beneath the moving contacts (203) to restrict the moving contacts (203) to a desired location.

However, the conventional push type switch has some drawbacks. Firstly, the conventional push type switch cannot prevent entry of water, dust particles etc which results in shortened life span. Secondly, due to vehicle vibration, the circlip (209) gets displaced from its position which results in a contact between the moving contacts (203) and the fixed contacts (212) even when the knob (201) is not pressed. Thirdly, grommet (205) is placed outside the metal body (204) in the conventional push type switch which results in a mechanical damage of the grommet (205). Lastly, the conventional push type switch is designed such that the switch cannot be used for both low as well as high ampere current.
Therefore, it is desirable to construct a switch which can overcome the above mentioned problems and protect its working parts from any external damage.

OBJECT OF THE INVENTION

The primary objective of the present invention is to develop a push type switch which prevents entry of water, dust, or other contaminants.

Another objective of the present invention is to enhance reliability of the switch by reducing the number of parts and assembly operations required to manufacture the switch.

SUMMARY OF THE INVENTION

The present invention discloses a push type switch designed in such a way that it prevents entry of dust, water or other contaminants that may affect the inner working parts of the switch.
In one embodiment of the present invention, a push type switch comprising a knob; a hollow plunger having a top end connectable to a bottom portion of the knob; moving contacts locatable around the hollow plunger; and a base located beneath the hollow plunger, said base comprising fixed contacts located thereupon; characterized in that the base comprises a shaft traversing into a bottom end of the hollow plunger thereby retaining the moving contacts at a desired location around the hollow plunger.

In another embodiment of the present invention, the hollow plunger, the moving contacts and the base are encased by a body.

In yet another embodiment of the present invention, a top surface of the body is provided with an aperture for enabling the top end of the hollow plunger to traverse through the body.

In still another embodiment of the present invention, the knob is locatable on an outer top surface of the body.

In another embodiment of the present invention, a sealing element is provided beneath an inner top surface of the body such that the same is located around the hollow plunger.

In yet another embodiment of the present invention, a spacer element is provided beneath an inner top surface of the body such that the same is located around the hollow plunger.

In still another embodiment of the present invention, the spacer element presses the sealing element against the inner top surface of the body.

In another embodiment of the present invention, a first spring is located in a space created between the spacer element and the hollow plunger.

In yet another embodiment of the present invention, a second spring is located between the shaft and the bottom end of the hollow plunger

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention are set forth with particularity in the appended claims. The invention itself, together with further features and attended advantages, will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only, with reference to the accompanied drawings wherein like reference numerals represent like elements and in which:

Figure 1 illustrates a sectional view of conventional push type switch.

Figure 2 illustrates an exploded view of conventional push type switch.

Figures 3-6 illustrate detailed view of various components of conventional push type switch.

Figure 7 illustrates a sectional view of the push type switch in accordance with an embodiment of the present invention.

Figure 8 illustrates an exploded view of the switch in accordance with an embodiment of the present invention.

Figures 9A and 9B illustrate a sectional view of the switch showing water protection from the top side in accordance with an embodiment of the present invention.

Figure 10 illustrate a sectional view of the switch showing water protection from bottom side in accordance with an embodiment of the present invention.

Figure 11 illustrate exemplary views of arrangement of the moving contacts inside the switch in accordance with an embodiment of the present invention.

Figures 12-15 illustrate detailed view of various components of the present invention.

DETAILED DESCRIPTION

The present invention generally relates to the control switches for automotive applications. In particular, the present invention relates to the construction of a push type switch that prevents entry of water, dust or other contaminants and enhances the reliability of the switch.

Figure 7 illustrates a sectional view of the push type switch in accordance with an embodiment of the present invention

Figure 7 illustrates the switch according to an embodiment of the present invention. Due to poor sealing mechanism, water and dust enters into the switch and damages its parts thereby affecting the working of the switch. Hence, in the present invention, the switch is provided with a robust design and an improved sealing mechanism. This enhances life of the switch due to prevention of direct entry of water, dust and other contaminants.

Figure 8 illustrate an exploded view of the switch in accordance with an embodiment of the present invention

In one embodiment of the present invention, the switch comprises of a body (801) and a base (802). The body (801) has a thread-like structure with a knob (803) mounted on an outer top surface of the body (801). The body (801) is provided with an aperture on the top surface through which one end of a plunger (804) is disposed and is connected to the knob (803). The plunger (804) is made up of plastic material and is hollow from inside. The plunger (804) is encircled by a sealing element (805) and a spacer element (806). This sealing element (805) and spacer element (806) protects switch from water, dust or other contaminants. The sealing element (805) is provided underneath an inner top surface of the body (801), due to which the mechanical damage of the sealing element (805) is avoided. The spacer element (806) is provided beneath the sealing element (805). One or more moving contacts (807) are located around the plunger (804). A first spring (808) is disposed in a space created between the spacer element (806) and the plunger (804) to push the moving contacts (807) downwards. The moving contacts (807) are fully encased by the body (801) and the plunger (804) is partially encased by the body (801).

The base (802) is disposed beneath the plunger (804) accommodating a shaft (809) and at least one fixed contact (810). The shaft (809) traverses into a bottom end of the plunger (804) thereby retaining the moving contacts (807) at a desired location. The fixed contacts (810) are further provided with at least two insulating washers (811) to disallow the fixed contacts (810) to move from its location. A second spring (812) is disposed between the shaft (809) and the plunger (804) to push the moving contacts (807) located around the plunger (804) back to its original location. The body (801) partially encasing the base (802) fixed into a plastic nut (813).

When the knob (803) is pressed, the first spring (808) forces the moving contacts (807) to move down and make a contact with the fixed contacts (810) located on the base (802). A closed circuit is formed thereby allowing the current to flow from the moving contacts (807) to the fixed contacts (810). Once the current is generated, the second spring (812) forces the moving contacts (807) to move back to its original position.

Figures 9A and 9B illustrate a sectional view of the switch showing water protection from the top side in accordance with an embodiment of the present invention.

As shown in figure 9A, one end of the sealing element (805) is held tightly on circular slots (901) provided on the plunger (804) and other end is disposed between the spacer element (806) and the body (801). The aperture provided on the body (801) is susceptible to the entry of water, dust or other contaminants. To prevent this, the sealing element (805) is disposed beneath the body (801). Multiple projections provided on the spacer element (806) acts as a stopper and control the compression of the sealing element (805).
As shown in figure 9B, the spacer element (806) is held at a required compression of the sealing element (805) by ultrasonic heat stacking (902). With this process, the sealing element (805) and the spacer element (806) remain intact on their respective locations and prevent entry of water, dust or other contaminants inside the switch and thus, protect the working parts of the switch from getting damaged.

Figure 10 illustrates a sectional view of the switch showing water protection from bottom side in accordance with an embodiment of the present invention.

In one embodiment of the present invention, the base (802) is connected to the body (801) by ultrasonic welding process (1001). This process prevents entry of water inside the switch during 15kgf/sq.cm pressure wash and hence, protects the electrical wires (1003). The fixed contacts (810) are engaged and soldered to the base (802). Hard epoxy (1002) potting is done on the soldered points. When the knob (803) is pressed the contact is made between the fixed (810) and the moving contacts (807), a closed circuit is formed thereby allowing the current to flow from the moving contacts (807) to the fixed contacts (810).Accordingly, current can flow from the contact to the electrical wires (1003) eliminating the need of at least one terminal to further pass on the current.

Figure 11 illustrate perspective views of arrangement of the moving contacts inside the switch in accordance with an embodiment of the present invention.

In one embodiment of the present invention, the plunger (804) is provided with at least one snap (1101) and at least one slit (1102). The slits (1102) enable the contraction of the plunger (804). With the contraction of the plunger (804), the moving contacts (807) locate around the plunger (804). The snaps (1101) provided on the plunger (804) hold the moving contacts (807) thereby, retaining the moving contacts (807) around the plunger (804). The shaft (809) traverses into the bottom end of the plunger (804) and prevents the contraction of the plunger (804).

Figures 12-15 illustrate detailed view of various components of the present invention.

Figure 12 illustrates the plunger (804) press fitted to the knob (803). This eliminates the need of an insert molding process. Figure 13 illustrates the knob (803) with a start symbol directly pad printed on it. Figure 14 illustrates the nut (813) having a washer like shape and hence, does not require a separate washer to tightly engage the body (801) to the nut (813). Figure 15 illustrates the assembly (1501) of moving contacts (807) snap fitted to the plunger (804). It retains the moving contacts (807) at a desired location. Hence, circlip is not required to restrict the moving contacts (807) to a desired location.

ADVANTAGES OF THE INVENTION

The present invention has following advantages:

i) The present invention is designed in a way to prevent entry of water, dust, oil, grease or other contaminants enhancing the life of the switch.
ii) The present invention is more reliable since it consists of less number of parts.
iii) The present invention can be used for both low as well as high ampere current.
iv) Less or no carbon deposition on the moving contacts because of waterproof design of the switch.
v) In the present invention, the sealing element is held inside the body, due to which the mechanical damage of the sealing element is avoided during handling.

While the particular preferred embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the teachings of the invention. It is therefore contemplates that the present invention cover any and all modifications, variations or equivalents that fall within the scope of the basic underlying principles disclosed above and claimed herein

We claim:

1. A push type switch comprising:
a knob;
a hollow plunger having a top end connectable to a bottom portion of the knob;
moving contacts locatable around the hollow plunger; and
a base located beneath the hollow plunger, said base comprising fixed contacts located thereupon;
characterized in that the base comprises a shaft traversing into a bottom end of the hollow plunger thereby retaining the moving contacts at a desired location around the hollow plunger.

2. The switch as claimed in claim 1, wherein the hollow plunger, the moving contacts and the base are encased by a body.

3. The switch as claimed in claim 2, wherein a top surface of the body is provided with an aperture for enabling the top end of the hollow plunger to traverse through the body.

4. The switch as claimed in claim 2, wherein the knob is locatable on an outer top surface of the body.

5. The switch as claimed in claim 3, wherein a sealing element is provided beneath an inner top surface of the body such that the same is located around the hollow plunger.

6. The switch as claimed in claim 3, wherein a spacer element is provided beneath an inner top surface of the body such that the same is located around the hollow plunger.

7. The switch as claimed in claim 6, wherein the spacer element presses the sealing element against the inner top surface of the body.

8. The switch as claimed in claim 6, wherein in a space created between the spacer element and the hollow plunger a first spring is located.

9. The switch as claimed in claim 1, wherein between the shaft and the bottom end of the hollow plunger a second spring is located.