Claims:We claim:

1. An operating assembly (200) for a molded case circuit breaker (MCCB) (500), being capable of rotatably coupling with an operating handle (300) using a shaft (250) therebetween,
characterized in that the operating assembly (200) comprising:
an inverted T-shaped housing (150) operably secured with the MCCB (500) using a limiting plate (10) sandwiched therebetween;
a rack (40) slidably secured on the limiting plate (10) being operably connecting with a knob (400) of the MCCB (500) on a bottom end;
a gear plate (10) positioned perpendicularly with the limiting plate (10) secured thereon;
at least one first gear (70) meshing with at least two second gears (50, 60) being fixedly secured to the gear plate (10), wherein the second gear (60) meshes with the rack (40) to facilitate a linear travel of the rack (40) on the limiting plate (10);
a semi-geared disc (80) adaptably meshing with the first gear (70) on an inner side (Not Numbered), and
a coupler (180) having a one side (Not Numbered) fixedly securing with an outer side (Not Numbered) of the semi-geared disc (80) through the inverted T-shaped housing (150) and an another end (Not Numbered) adaptably configured to receive the shaft (250) therein,
wherein upon rotation of the operating handle (300) from one position to another transfers the rotation motion to shaft (250) to rotate coupler (180) which therefrom transmits the torque to the semi-gear disc (80) which meshes the first gear (70) and the second gear (60) thereby translates rotational motion into linear motion of the rack (40) to switch the knob (400) of the MCCB (500) into an operational position.

2. The operating assembly (200) as claimed in claim 1, wherein the inverted T-shaped housing includes a top portion (Not Numbered) with a circular opening (Not Numbered) for engaging with the coupler (180), and an open bottom portion (Not Numbered) operably secured with the limiting plate (10).

3. The operating assembly (200) as claimed in claim 1, wherein the operating assembly (200) adaptably facilitates to operate the MCCB (500) placed horizontally to form a table top arrangement with a panel door (350) positioned outside.
, Description:OPERATING ASSEMBLY FOR MOLDED CASE CIRCUIT BREAKER

Field of the invention

The present invention relates to a manual operating mechanism of a circuit breaker and more particularly, to a rotary operating mechanism for manual operation of a molded case circuit breaker’s (MCCB) from outside the panel.

Background of the invention

Circuit breaker basically serves as a switching device for switching On/Off during normal operating conditions for the purpose of operation and maintenance. It also serves as a protecting device that trips or isolate by breaking the contacts interrupting the fault current during abnormal conditions such as short-circuit, overload and under voltage.

Circuit breaker consists of one or more electric poles, whose number is determined by the application that is single pole circuit breaker, two pole circuit breaker, three pole circuit breaker, four pole circuit breaker and so on.

The circuit breaker is designed for use in switchboards, control panels, and combination starters in separate enclosures for effective single location distribution and control. Also, these are housed in an enclosure to provide safety to users operating the same. In the most common type of installation, an operating handle is mounted on the panel door while the switching device is mounted inside the panel door. The mounting device has a shaft coming out that has to be rotated to switch the circuit breaker ON and OFF.

When panel door is closed, the shaft engages with the handle mounted on the panel door and breaker can be operated by using the handle. When panel door is open the handle decouples with the shaft and no engagement is left with the shaft and handle. Hence, under standard design conditions while a door is open, due to this condition the operation of the circuit breaker is not possible, which is a must from a safety perspective as the operating a handle under these conditions would be unsafe because of live power inside the enclosure.

In another type of installation, the circuit breaker is mounted on the table top configuration, which further calls for a mechanism which ensures side operation of the switching device. This kind of installations allows for reduced depth of panels and added space for arc chambers.

In a US Patent Application 5493083, a rotary control device for a circuit breaker, notably a three-phase circuit breaker of industrial type, the circuit breaker comprises a front closing plate provided with an opening through which there passes a pivoting crank pin able to occupy at least two stable extreme positions. The device comprises a housing mounted on said front plate, a rotary handle securely united to this housing and a mechanism to couple said handle and said crank pin. The design is however too complex and does not clearly address issues of door interlock defeat and its restoration.

Further, US patent applications 6518526 and 6969813 cites the example of rotary add-on mechanism connected to a switching device but it fails to disclose the operational safety aspects of door interlock.

Similarly, patent application UA6518526 discloses a bevel gear based model that engages the MCCB shaft direct with the handle. But it fails to disclose about the conversion of rotation motion into linear operation, instead, it is transferred to a perpendicular axis using a bevel gear.

Another, US patent application 5493083 cites operational conversion using a scotch yoke mechanism. The mechanism is a cam based mechanism citing examples of door interlocking but fails to touch on the aspects of door sensing.The mechanism primarily talks about a key lock facility and also nominates a poka-yoke in mounting as a novel feature.

Yet another US patent application 6969813 discloses a handle drive mechanism used essentially to open welded contacts and thereby isolation. The invention is essentially conceptualized for small panel requirement for table top mounting of MCCBs. The invention is to overcome the big size of panel and their space requirements. The application fails to talk about interlocking / sensing or key locking features.

Accordingly, there is a need to design an operating assembly that facilitates side operation of a MCCB on a table top arrangement with interlocking , and safety features to overcome the above-mentioned drawbacks of the prior art.

Objects of the invention

An object of the present invention is to ensure safe side operation of a MCCB on a table top arrangement for smaller panels.

Another object of the present invention is to facilitate correct indication of the switching device state inside the panel.

Yet another object of the present invention is to have a working torque within the operational ergonomic limits.

Still another object of the present invention is to provide simple construction, user-friendly and cost-effective assembly.

Another object of the present invention is to facilitate retrofit engagement with existing extended handle mechanisms complying with safety requirements.

Yet another object of the present invention is to keep maximum components common with the existing art without need of replacement.

Summary of the invention

Accordingly, the present invention provides an operating assembly for a molded case circuit breaker (MCCB) which is capable of being rotatably coupled to an operating handle using a shaft therebetween. The operating assembly comprises an inverted T-shaped housing, a rack, a gear plate, at least one first gear meshing with at least two second gear, a semi-geared disc and a coupler. The inverted T-shaped housing is operably secured with the MCCB using a limiting plate which is sandwiched therebetween. The rack is slidably secured to the limiting plate which is operably connected with a knob of the MCCB on a bottom end. The gear plate is positioned perpendicularly with the limiting plate secured thereon. The first gear meshing with two second gears is fixedly secured to the gear plate. The second gear meshes with the rack to facilitate a linear travel of the rack on the limiting plate. The semi-geared disc is designed to adaptably mesh with the first gear on an inner side. The coupler has a one side fixedly secured on an outer side of the semi-geared disc through the inverted T-shaped housing and an another end adaptably configured to receive the shaft therein.

Further, when the operating handle is rotated from one position to another, the rotation motion is transferred to the shaft to rotate coupler. The coupler, in turn, transmits the torque to the semi-gear disc. The semi-gear disc by meshing through the first gear and the second gear translates rotational motion into linear motion of the rack to switch the knob of the MCCB into an operational position.

Brief description of the drawings

Other features, as well as the advantages of the invention, will be clear from the following description.

In the appended drawings:

Figure 1 shows a perspective view of an operating assembly connected by a shaft to an operating handle placed on a panel door for a molded case circuit breaker (MCCB) in accordance with the present invention;
Figure 2 shows a perspective view of an inoperable condition of the operating assembly without the operating handle, in accordance with the present invention;
Figure 3 shows a front perspective view of the operating assembly without a housing, in accordance with the present invention;
Figure 4 shows a rear perspective view of the operating assembly without the housing, in accordance with the present invention;
Figure 5 shows a perspective view of meshing of a plurality gears on a limiting plate of the side operating assembly, in accordance with the present invention, and
Figure 6 shows a cross-sectional view of the operational arrangement of the operating assembly with the MCCB, in accordance with the present invention.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides an operating assembly connected by a shaft to an operating handle placed on a panel door for a molded case circuit breaker (MCCB). The present invention ensures safe side operation of a MCCB on a table top arrangement for smaller panels. The present invention facilitates retrofit engagement with existing extended handle mechanisms complying with safety requirements. The components of the present invention hold the extended shaft in the same operating quadrant as that of the existing operating handle of MCCB known in the art.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.

Referring to figures 1 to 6, various views of an operating assembly (200) for a molded case circuit breaker (hereinafter referred as ‘MCCB’) (500) are illustrated. The operating assembly (200) for the MCCB (500) is rotatably coupled to an operating handle (300) using a shaft (250) therebetween as shown in figure 1. The operating handle (300) is used to operate the MCCB (500) or switching device in its various states of ON/OFF/TRIP/RESET. The operating assembly (200) adaptably facilitates to operate the MCCB (500) placed horizontally to form a table top arrangement with a panel door (350) positioned outside. Referring to figure 3, the open end condition of the panel where the operating handle (300) moves out of the operating assembly (200) rendering it inoperable because of the lack of operating handle (300) is shown. The operating assembly (200) essentially serves the purpose of converting a toggle type switching device into a rotary type switching device.

The operating assembly (200) comprises of an inverted T-shaped housing (150), a rack (40), a gear plate (10), at least one first gear (70) meshing with at least two second gear (50, 60), a semi-geared disc (80) and a coupler (180). The inverted T-shaped housing (150) is operably secured with the MCCB (500) using a limiting plate (10) which is sandwiched therebetween. The inverted T-shaped housing includes a top portion (Not Numbered) with a circular opening (Not Numbered) for engaging with the coupler (180), and an open bottom portion (Not Numbered) operably secured with the limiting plate (10).

Referring to the figures 4 and 5, the rack (40) is shown to be slidably secured to the limiting plate (10) which is operably connected with a knob (400) of the MCCB (500) on a bottom end. The rack (40) includes a plurality of tooth (Not Numbered) on a top portion and a bottom portion adaptably configured to engage with the knob (400). The rack (40) is placed in proximity to the gear plate (10).

The gear plate (10) is positioned perpendicularly with the limiting plate (10) secured thereon. The gear plate (10) is provided with a plurality slots to enable fixing of a number of gears thereon using fixing means such as screws, rivet and the like known in the art. The gearing used in the present invention has efficiency in the range of 95% which along with proper lubrication brings down the frictional force and limiting the operating torque. Thus the gearing thereby provides a working torque within the operational ergonomic limits. In the present embodiment, the first gear (70) meshing with two second gears (50, 60) is fixedly secured to the gear plate (10) as shown in the figures 4 and 5. The second gear (60) meshes with the plurality of tooth of the rack (40) to facilitate a linear travel of the rack (40) on the limiting plate (10).

The semi-geared disc (80), as shown in figure 4, is designed to adaptably mesh with the first gear (70) on an inner side (Not Numbered). The semi-geared disc (80) includes a cavity (80a) adapted to receive a torsional spring (Not Shown / Not Numbered) placed below the semi-geared disc (80); this facilitates correct indication of the switching device state inside the panel. The torsional spring gets charged on clockwise rotation and adaptably brings back the operating handle (300) to trip position when the MCCB trips. The coupler (180) is fixedly secured on a one side (Not Numbered) with an outer side (Not Numbered) of the semi-geared disc (80) through the circular opening of the inverted T-shaped housing (150) having the torsional spring therebetween. The coupler (180) on an another end (Not Numbered) is adaptably configured with a slot (Not Numbered) to receive the shaft (250) therein.

Further, when the operating handle (300) is rotated from one position to another, the rotation motion is transferred to shaft (250) to rotate coupler (180). The coupler, in turn, transmits the torque to the semi-gear disc (80). The semi-gear disc (80) by meshing with the first gear (70) and the second gear (60) translates rotational motion into linear motion of the rack (40) to switch the knob (400) of the MCCB (500) into an operational position. Thus, on rotation of the operating handle (300), the gears rotate thus moving the rack (40) through the different positions of ON/TRIP/OFF/RESET.

Advantages of the invention

1. The operating assembly (200) facilitates correct indication of the switching device state inside the panel.
2. The operating assembly (200) provides working torque within the operational ergonomic limits.
3. The operating assembly (200) facilitates simple construction, user-friendly and cost-effective assembly.
4. The operating assembly (200) is retrofit engagement with existing extended handle mechanisms complying with safety requirements.
5. The operating assembly (200) allows keeping maximum components common with the existing art without need of replacement.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.