CN117916842A - Improved and simplified multifunctional two-bar mechanism and improved miniature circuit breaker - Google Patents

Abstract

The present invention relates to an improved and simplified operating mechanism for a miniature circuit breaker having only a two bar assembly. The two-bar mechanism is capable of achieving a mechanism on-off position, its primary function being to determine and control whether the circuit breaker is in a closed (on) or open (off) state, and has a no trip feature.

Description

Improved and simplified multifunctional two-bar mechanism and improved miniature circuit breaker

Technical Field

The present invention relates to an improved and simplified multifunction miniature circuit breaker having only a two pole assembly and other features. The two-bar mechanism enables mechanical on-off with no trip feature, true contact position, sort circuit indication test button mechanism verification, automatic reset, thermal trip, magnetic trip, multipole coupling, and accessory/accessory coupling.

Background of the invention

The circuit breaker protects the circuit from damage caused by current surges by interrupting or breaking the current path between the input terminal and the output terminal. A conventional miniature circuit breaker includes a pair of contacts in a main current path between a line terminal for connection to a power supply and a load terminal for connection to a load powered by the power supply.

Conventional miniature circuit breakers also include a mechanism by which the miniature circuit breaker can be operated and signals obtained from heat release and magnetic release for circuit protection during abnormal conditions or faults. These mechanisms are often complex in nature in that they must provide many functions to operate with optimal force with minimal trip force and optimal contact pressure. At the same time, a higher speed is required to break the arc faster during a short circuit.

The traditional mechanism involves:

A manually operated handle having one end coupled to the link and the other end connected to the jump joint. The skip is connected to a trip bar that obtains signals from the heat release and the magnetic release in the event of a fault, resulting in the mechanism tripping automatically independent of the handle, referred to as a no trip feature. The moving contact is mounted on the contact support bar and rotates together with the contact support bar.

One such device in which the jump bar is formed by a bore designed to engage the end of the link directly. Such a mechanism is a "watch mechanism" making it difficult to manufacture, involving 3 or more poles, making it time consuming to assemble.

The object of the present invention consists of a miniature circuit breaker mechanism comprising a minimum number of parts making it easy to manufacture and assemble while operating with optimal force.

This background information is provided to make known information that the applicant believes may be relevant to the present invention. It is not necessarily to be construed as an admission that any of the preceding information constitutes prior art against the present invention.

Summary:

The present invention relates to an improved and simplified multifunction miniature circuit breaker having only a two-bar mechanism. The two-bar mechanism is capable of a mechanical on-off position, which is the primary function of determining and controlling whether the circuit breaker is closed (on) or open (off) using a no-trip feature. The no-trip feature ensures a positive trip in the event of a fault, even if the handle is held in the open position (closed loop J) by force. Moreover, the true contact position indication is built into the two bar mechanism, where it will show the status of the ring inside the circuit breaker, whether the handle position is on or off. Further, short circuit fault indications have been added to aid in understanding that the circuit breaker has tripped due to a fault or that it has been closed for maintenance purposes. Moreover, test buttons for the mechanism are added to provide mechanical verification of the miniature circuit breaker trip function during routine testing or when the miniature circuit breaker is stacked in a panel. The improved two-bar mechanism also has a thermal trip feature that covers one of the primary functions of providing protection during overload fault conditions, as well as magnetic tripping that effectively receives signals from the magnet in any short circuit fault. The improved two-bar mechanism has the ability to connect multipole coupling and accessory/accessory coupling features. An advantage of the improved two bar mechanism is that, along with multiple features, it is easy to manufacture and assemble, while having optimal force, minimum trip force and optimal contact pressure, while quickly clearing faults through the finger profile.

Disclosure of Invention

It is an object of the present invention to provide an improved simplified mechanical device for a miniature circuit breaker and a miniature circuit breaker comprising the device. The current state of the art is an improvement over patent publication nos. 1049778 and IN 201917047208. Multiple contours have been added to two-bar mechanisms to achieve multiple functions and features while making them easy to manufacture, assemble and operate with optimal forces. This prior art also has the claim for improvement of prior art EP1703533 A2. The shorting feature is implemented using only 2 parts ensuring ease of assembly, whereas EP1703533A2 uses 3 parts.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

fig. 1: a miniature circuit breaker according to aspects of the invention is shown, showing in detail the following components: handle spring (1), handle (2), connecting rod (3), contact supporting spring (4), contact bracing piece (5), mechanism spring (6), base (7), movable contact subassembly (8), movable contact spring (9), trip bar (10), holding spring (11) and hot slider (12), short circuit instruction (13) and (14).

Fig. 2: the components of the two-bar mechanism and associated components are shown when the miniature circuit breaker is in the open-loop position (off).

Fig. 3: the components of the two-bar mechanism and associated components are shown when the miniature circuit breaker is in the closed-loop position (on).

Fig. 4: the components of the two-bar mechanism and associated components are shown when the miniature circuit breaker is in the no-trip position, while the on-off operation of the two bars allows the mechanism to have a no-trip feature and reset.

Fig. 5: an accessory coupling position with two lever mechanism components is shown.

Fig. 6: a multipole coupling position with two lever mechanism components is shown.

Fig. 7: a simplified two-bar assembly is shown.

Fig. 8: showing aspects of the invention, one of the components of a simplified two-bar mechanism is shown in detail as a contact support bar, which, as shown in fig. 1, will be assembled on a base (7) by a mechanism pin (6) through the centre of the contact support (5.2), also the mechanism pivot centre, the radial rotation of the contact support bar (5) being controlled by the handle (2) and through the link (3).

When the miniature circuit breaker is switched to the off position, the rotation of the contact support bar (5) has a stop in the base (7) that positively stops the mechanism on a mating surface in the contact support (5.1). Also shown is a shaft (5.3) for moving the contact sub-assembly (8) protruding from the top on the contact support bar, making it easy for automatic assembly. One stop is reserved to reduce bouncing of the moving contact (5.8), and the other stop (5.9) is provided to reduce swinging during normal closing or failure, and is to be locked by a moving contact spring (9), which has 2 stops, one end of which is to be assembled in the contact support (5.4) and the other end of which is in the moving contact (8). A part of the bottom side of the contact support bar has an opening spring (4) assembled at the central surface of the contact support (5.5) and is caught by 2 arms, one arm stopping at the top of the contact support center (5.7) and the other arm stopping at the bottom center of the contact support (5.6), once assembled in the base (7), one arm of the spring resting on (5.7) will rest on the base stop, and finally but not least, the top surface in the contact support bar (5.11) serves as an indication feature with green (off) and red (on) indications.

Fig. 9: the aspects of the invention are shown in detail showing the other part of the simplified two bar, which is the trip bar (10), as shown in fig. 1, the trip bar (10) assembly is at the top of the contact support bar (5), through the center (10.4) via the mechanism pin (6), which is also the mechanism pivot center and is locked by the holding spring (11) with 2 arms, one arm stopped by the trip bar spring stop (10.6) and the other arm stopped by the spring stop at the contact support bar (5.10). However, the magnetic fault signal and the thermal fault signal occur in the rear wall of the trip bar (10.8) and the hot slider groove (10.5), respectively. At the trip bars shown in fig. 5 and 6, the slot connectors for auxiliary coupling and multipole coupling are shown in (10.3) and (10.7), respectively. The lifting feature for lifting the link (3) out and unlocking the miniature circuit breaker is a finger feature (10.1). An extension profile (10.2) is held in the trip bar to provide access protection.

Fig. 11: aspects of the present invention are shown for a rail holder with the addition of a sliding feature. This feature enables easy replacement/maintenance of the miniature circuit breaker when stacked with other miniature circuit breakers in the panel, particularly when the panel is wired. The sliding feature enables the miniature circuit breaker to slide when unscrewed from the bus bar panel, and thus it can be removed without having to remove other miniature circuit breakers.

Detailed description of the invention

The present invention provides a miniature circuit breaker shown in fig. 1 with a simplified two-bar mechanism (5 and 10) that effectively achieves multiple functions in one assembly containing only two bars. The simplified two-bar mechanism enables mechanical on-off operation with no trip feature, true contact position, on-off indication, automatic reset, thermal trip, magnetic trip, multipole coupling, and auxiliary/accessory coupling.

Referring to the drawings, the miniature circuit breaker of fig. 1 is provided with a two-bar assembly 7 to obtain functions/features. The miniature circuit breaker (1) comprises a housing or shell, optionally provided in two connectable halves, and the circuit breaker assembly provides a main current path between an input terminal and an output terminal. The housing or shell is typically plastic and includes suitable mounting and insulating elements. The miniature circuit breaker assembly includes a mechanical mechanism shown in fig. 7, operably connected to a handle (2), a linkage (3), a contact support bar (5), a trip bar (10), and a moving contact sub-assembly (8). The handle assembly is movable between a normal position and an abnormal or fault position (indicating a circuit trip) and includes an operating member or handle (2) and an associated handle spring (1). The handle assembly is connected to the contact support bar (5) and the trip bar (10) by a link (4).

The handle spring (1) is configured to bring the handle (2) to the off position when the miniature circuit breaker (1) trips, as shown in figures (1) and (2).

As shown in the figure, the two-bar assembly shown in fig. 7 is controlled by the link (3) and held by the holding spring (11) to engage the two bars in one rotational path, each time the miniature circuit breaker is in the open position shown in fig. 2, the two bar assembly will rotate at an angle that allows the moving contact to make contact with the magnetic assembly to pass current, in an abnormal/fault condition the magnetic release the trip bar by pushing the rear wall of the trip bar (10.8), whereby the trip bar is configured to convert the linear force from the magnetic assembly into a rotational force to open the mechanism, and when the opening mechanism is activated, the finger profile (10.1) in the trip bar pushes the link (3) rapidly to release the mechanism and trip the circuit breaker, the contact support bar (5) rotates counter clockwise with the moving contact sub-assembly (8).

Referring to fig. 1, the contact support bar 5 includes an opening spring 4 assembled toward the rear side at the surface of the contact support 5.5 as shown in fig. 8. The opening spring (4) together with the two-bar mechanism stores energy in an on-off state and a fault state, facilitating the separation of the contacts by providing the opening speed required to rotationally move the contact sub-assembly (8) during a trip operation.

A test button (15) is coupled to the two-bar mechanism to perform the unique function of "trip verification". This function is useful for verifying the health of the trip mechanism. Such verification may be used during routine testing as well as during installation/maintenance. The access of the test button makes it easy to test the health of the trip mechanism even when miniature circuit breakers are stacked in the distribution panel.

Both short circuit trip indications (13) and (14) are assembled in the base (7) to provide clear identification of fault conditions. It becomes very tricky for a person skilled in the art to identify whether the miniature circuit breaker is tripped or whether it is closed. To distinguish this, short circuit trip indications (13) and (14) are added to the improved two bar mechanism.

For an abnormal/thermal fault condition, a signal will be sent from the thermal subassembly (8) to the trip bar (10.5), through the thermal slider bar (12), the trip bar is configured to convert the linear force from the thermal slider bar (12) into a rotational force acting on the thermal slider slot (10.5), the thermal element (13) will rotate clockwise and force the thermal slider, the rotational force from the thermal element (13) will be converted into a linear force by the thermal slider, so the trip bar will move counter-clockwise to open the mechanism, when the opening mechanism is activated, the finger feature (10.1) pushes the link (3) to release the mechanism and trip the circuit breaker as previously described. Having such a metallic hot slider/stem would have a robust calibration and less likelihood of melting the plastic in contact with the heater element.

Referring to fig. 10, the accessory couplings may be connected by a trip bar. An auxiliary slot (10.3) as shown in fig. 5 and a multipole coupling connected by a multipole slot (10.7) as shown in fig. 6.

Claims (8)

1. We claim that:

An improved operating mechanism for a miniature circuit breaker having fixed and moving contacts supported by a contact support actuated by the mechanism between a closed position and an open position, the mechanism comprising:

A manually operated handle having one end coupled to the link and the other end connected to a "cup-shaped" profile formed by the dual lever mechanism assembly; trip means including thermal overload trip means having a bi-metal strip (a thermal element), and/or electromagnetic trip means having a plunger (part of a magnetic assembly);

A contact support bar, wherein the movable contact arm is hinged on the pivot of the contact support, allowing a small amplitude of relative pivoting movement between the movable contact and the contact support bar due to the presence of the contact pressure spring and the overtravel;

a trip lever (10) pivotally mounted on the contact support bar (5) and having a suitable profile to trigger the tripping of the mechanism by a thermal or magnetic release signal in the event of a fault, resulting in the mechanism tripping automatically independently of the handle (2).

2. The improved circuit breaker operating mechanism of claim 1 wherein: a "finger-like" profile (10.1) is added in the trip bar (10) to push the link, thus enabling quick unlocking of the mechanism and thus faster opening of the miniature circuit breaker in case of an abnormal situation/failure.

3. The improved circuit breaker operating mechanism of claim 1 wherein: a profile (kidney or circle) (10.5) is provided in the trip bar (10) to connect the heat release means by means of a metallic hot slide bar/piece (12) to initiate tripping (opening) of the circuit breaker by moving the heater element/bimetal during overload faults.

4. The improved circuit breaker operating mechanism of claim 1, coupled with a test button (15) for mechanical verification of trip function;

short circuit indicators (13 and 14) which can be realized with only two elements to indicate a fault caused by a short circuit.

5. The improved circuit breaker operating mechanism of claim 1 having only two specially contoured rods which enable a number of features as set forth below:

a. easy to manufacture and assemble (top-insertion thermal assembly);

b. Quick opening (finger profile (10. L));

c. On-off with no trip feature (fig. 4);

d. Thermal tripping (10.5);

e. magnetic tripping (10.8);

f. multipole coupling (fig. 6);

g. Accessory coupling (fig. 5);

h. True on-off indication (5.11).

6. A stop contour (5.9) is provided in the contact support (5) to prevent oscillations and to suppress bouncing phenomena of the moving contact.

7. An extended profile feature (10.2) is added to the trip bar to provide ingress protection against foreign matter.

8. A special profile is added in the rail holder, which allows more sliding in view of the ease of replacement/maintenance.