Description: “Flat Bell Push Switch”.
FIELD OF INVENTION
[001] The present invention relates in general to switches. The present invention more particularly relates to flat bell push switch involving return operation without the implementation of restoring spring.

BACKGROUND/PRIOR ART

[002] Various types of switches are known to be available in the market including Electrical, Electronic, Magnetic switches. Further, said electrical switches comprise of rocker switch, push button switch, rotary switch, slide switch and bell push switch. The present invention focuses on flat bell push switch.

[003] Generally in flat bell push switch, the switch returns to its default position (off position) immediately as soon as the pressure is released from knob which is applied by the finger. The restoring force is provided by the spring that is installed inside the switch. Now, the same will be described hereinbelow.

[004] The known bell push switch comprises Knob, Plunger spring, Plunger, Rocker, Base, Fulcrum Terminal, Fixed Terminal and Screws.

[005] The existing bell push switch is having a small cylindrical cavity on the back of the knob to accommodate a plunger (P) with plunger spring (L). On the same side of the knob there is a small star projection to house another spring (S) connected with the base (B). The other side of the knob is provided to be plain where operating force can be applied during operation of the switch.

[006] The plunger guided in the cylindrical cavity is always pushed towards the rocker (R) with the help of the force provided by the plunger spring (L). The rocker is placed in such a way that it can swivel on the fulcrum terminal (T) during OFF position when the knob is not pressed.

[007] The fixed terminal (F) and fulcrum terminal (T) are properly guided within the arc shield (A) and held in position by the cavity in base for terminal holding. The switch is also provided with screw holes (H) for fastening.

[008] In the course of the operation of this bell push switch when the force is applied on the knob with the finger, the spring connected with base and knob starts compressing and storing energy. Also during the operation the plunger spring starts compressing and plunger moves towards the fulcrum point.

[009] Plunger applies the rotational movement to the rocker and due to this rocker swivels to a position that the contact is made between the rocker and fixed terminal resulting in the closed circuit.

[0010] Since the circuit is closed in this position of switch, therefore it is called ON position. At this position the spring force is balanced by the force applied by the finger and the circuit remains in closed position as long as force is applied on the knob. When the force is released from knob by removing finger the energy starts releasing. During this spring applies force in backward direction i.e. on the knob. The backward force causes the knob to swivel back to original position i.e. OFF position.

[0011] Thus, the operating mechanism of normal bell push is achieved by means of plunger spring and an additional spring placed between the base and the knob as discussed hereinabove.

[0012] Now, further reference may be made to Patent Application No. 2787/MUM/2014 relating to a self-running portable bell and alarm, which is a sound indicator that does not require any external source of electricity for operation thereof and it is a portable device that can be easily used anywhere. It comprises of a slider crank mechanism with spring return piston, a gear transmission, generator driven by the gear transmission and an electric bell or any indicator.

[0013] The disadvantages associated with the above can be listed hereinbelow.

- High cost owing to presence of additional spring
- Requirement of more skilled labour for manufacture
- Sophisticated
- More time consuming assembly
- Requirement of special assembly fixture which again adds to cost.

[0014] In view of the above, it is required to devise a flat bell push switch which can address the aforesaid issues and serve the purpose efficiently without the use of extra spring providing the restoring force.

[0015] Some other types of switches are also available in the art, which can be referred to just for the study as follows:

[0016] Patent No. US6778048 (B1) relates to an assembly for interacting with a circuit breaker operating mechanism of a circuit breaker including a housing and a pair of contacts within the housing. The operating mechanism is provided to separate the pair of contacts upon the occurrence of a trip event. The assembly includes a plurality of linkages arranged to transmit mechanical energy from the operating mechanism to a plunger of an accessory device for changing a state thereof. The system of linkages is configured to compensate for any over-travel resulting from possible tolerance variations.

[0017] Patent No. FR2371741 (A1) relates to an electromagnetic coil and plunger mechanism is used to strike a resonating bar or bell. It can be driven by an oscillator or by a self-oscillating circuit. The mechanism has a coil, a magnetic plunger with an extension. The coil is connected to a battery through a push-button switch and a reed switch. One end of the plunger has a permanent magnet. Displacement of the plunger releases the reed switch and de-energises the coil. The reed switch closes and re-energises the coil.

[0018] Patent No. DE4004337 (C1) is directed to a doorbell switch having a hinged actuator panel retained flat against a housing panel sealing element when assembled. A projecting lug retains the panel. When finger contact section is pressed the panel moves a small amount to displace a plunger to operate the contact assembly.

[0019] Patent No. 20070125635 discloses a casing, affixed to the supporting ring, equipped with an external operating key, whose hollow interior features interchangeable sets of contacts. The rocker transmits the pressure exerted on the key to a swinging contact and furthermore features two pivots with two swinging contacts and a single pivot in that of a single swinging contact.

[0020] However, none of the above can fulfill the requirements for which the present invention has been devised.

OBJECTS OF THE INVENTION:

[0021] An object of this invention is to propose flat bell push switch which obviates shortcomings of the prior art(s).

[0022] Another object of this invention is to propose flat bell push switch which is simple in construction and cost effective.

[0023] Further object of this invention is to propose flat bell push switch which involves less time consuming assembly.

[0024] Still further object of this invention is to propose flat bell push switch which does not need restoring spring.

SUMMARY OF THE INVENTION:

[0025] According to this invention, there is provided a flat bell push switch comprises a knob, back side of which is provided with a cavity to accommodate plunger with plunger spring, which is pushed toward rocker, which can swivel on fulcrum terminal during OFF position, and the fulcrum terminal and fixed terminal are guided within the arc shield wherein the switch return operation is accomplished by the torque provided by the plunger spring generating the force for the change in state of electrical circuit.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:

[0026] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings of exemplary embodiments of invention and wherein:

Fig. 1(A) shows: Conventional flat bell push switch in OFF position.
Fig. 1(B) shows: Conventional flat bell push switch in ON position.
Fig. 1(a) and (b) shows: Side and Sectional view of the flat bell push switch of present invention in OFF mode.
Fig. 2(a) and 2(b) shows: Side and Sectional view of the flat bell push switch of present invention in ON mode.
Fig. 3 shows: Exploded view of flat bell push switch according to present invention.
Fig. 4 shows: Function of switch in ON and OFF position.

DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS

[0027] The instant invention is pertinent to flat bell push switch, which accomplishes flat bell switch return operation without the use of restoring spring.

[0028] Reference may be made to fig. 1a and 2a depicting OFF and ON position of switch respectively and sectional view thereof in figure 1b and 2b.

[0029] Now referring to figure 3, the flat bell push switch comprises a knob (1), back side of which is having a cavity to accommodate a plunger (3) with the plunger spring (2). On the same back side of said knob (1), a hinge is provided. So that, the hinge can swivel on the base above around point ‘O’ during the ON/OFF operation of switch as illustrated in the figure 4(a).

[0030] The other side of the knob (1) is substantially flat to apply operating force during the operation of the switch. The plunger (3) guided in the cylindrical cavity is always pushed towards the rocker (4) with the help of force exerted by the plunger spring (2). The rocker (4) of the switch is also pushed onto the fulcrum terminal (7) by the force applied by the plunger spring (2). The rocker (4) is placed in such a way that it can swivel on the fulcrum terminal (7) during OFF position when the knob (1) is not pressed. The fixed terminal (8) and the fulcrum terminal (7) are properly guided within the arc shield (6) and held in position by the terminal holder (9). The position in which rocker (4) does not establish contact with the fixed terminal (8) leads to open circuit, thereby setting the flat bell push switch at off position.

[0031] During operation of this Flat Bell Push switch when force is applied on knob (1) at an end, farther from the fulcrum point (7) with the finger, the plunger spring (2) starts compressing and simultaneously starts storing energy. Further, during this operation the plunger (3) starts moving towards the fulcrum point ‘W’ as shown in figure 4 (b). During this movement the plunger (3) also applies the rotational movement to the rocker (4) and due to this rocker (4) swivels to a position that the contact is established between the rocker (4) and the fixed terminal (8) causing the closed circuit. The closed circuit sets the switch in ON position. At this position the spring force is balanced by the force applied by finger and the circuit remains in closed position as long as force is applied on the knob. When finger is removed from the knob and force is released from knob, the energy stored in the spring starts releasing. During this, spring applies force in backward direction i.e. on the knob. This backward force causes the knob to swivel back to original position i.e. OFF position. Due to this movement of the knob, the plunger (3) slides over rocker (4) and makes rocker (4) swivel over fulcrum terminal (7) causing it to come to its normal position. With this also the switch returns to its initial position i.e. at OFF position.

[0032] Hence the entire working mechanism of the Flat Bell Push Switch according to the present invention relies on the plunger spring force with no need of any auxiliary spring to bring the knob to its initial position unlike in other bell push switch of prior arts.

[0033] Flat bell switch return operation is achieved by the torque provided by the plunger spring (2) which generates the force for the change in state of electrical circuit.

[0034] Thus, the flat bell push switch of invention works in a manner similar to the normal bell push switch by serving the same purpose, but with a different mechanism relying on different concept as already discussed hereinabove.

[0035] Advantageous Features

- Cost effective
- Less time consuming assembly
- Reduction in the rate of rejection owing to removal of spring
- Simple in construction.

[0036] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims:-

Claims:WE CLAIM:

1. A flat bell push switch comprises a knob, back side of which is provided with a cavity to accommodate plunger with plunger spring, which is pushed toward rocker, which can swivel on fulcrum terminal during OFF position, and the fulcrum terminal and fixed terminal are guided within the arc shield wherein the switch return operation is accomplished by the torque provided by the plunger spring generating the force for the change in state of electrical circuit.

2. A flat bell push switch as claimed in claim 1 wherein said back side of the knob of switch is having a hinge for making the knob swivel on the base above around a particular point during the ON/OFF operation of switch.

3. A flat bell push switch as claimed in claim 1 or 2 wherein the knob of switch, front side of which is substantially flat for application of operating force during the operation of the switch.

4. A flat bell push switch as claimed in any of the preceding claims wherein the operation of the switch comprises steps of:-

- application of force by finger at an end of the knob farther from the fulcrum point for compression of the plunger spring so as to store energy,
- movement of the plunger towards the fulcrum point to apply rotational movement to the rocker, which makes the rocker swivel to a position for establishing contact between the rocker and fixed terminal so as to switch ON,

- removal of finger from the knob for releasing energy stored in the spring thereby rendering the knob to swivel back to original position so as to switch OFF,

- sliding of the plunger over the rocker, thereby making the rocker swivel over fulcrum terminal causing the same to return to normal position thereof and switching off.

5. A flat bell push switch as claimed in any of the preceding claims is associated with the advantageous features such as herein described.