A pneumatic protection device for a molded case circuit breaker

Abstract

The present invention relates to a pneumatic protection device for a molded case circuit breaker, which includes a base (1), a spring (2), a push rod (3), a slider (4) and a cover plate (5). The base (1) is provided with three relatively independent ribs: rib a (11), rib b (13) and rib c (16). The three ribs and the base (1) together enclose two independent cavities: cavity a (12) and cavity b (14). The slider (4) is triangular. Its top surface (41) contacts the push rod (3). A chute (43) is provided between the lower two feet. The rib b (13) is inserted into the chute (43) to enable the slider (4) to move up and down along the rib b (13). The two feet are respectively placed in the cavity a (12) and the cavity b (14). Compared with the prior art, the present invention has the advantages of controllable force and high safety.

Description

Technical Field

[0001] The present invention relates to a circuit breaker, and more particularly to a pneumatic protection device for a molded case circuit breaker. Background Art

[0002] During the operation of a circuit breaker, when a short-circuit fault occurs in a certain phase, timely and rapid tripping is required. During the tripping process, the tripping mechanism is often triggered by an external linkage mechanism. There are various triggering methods in the prior art to drive the tripping mechanism. The tripping achieved by the gas protection method has better effects because it utilizes the heat generated by the short-circuit current to expand the gas and drive the mechanism to operate to achieve tripping.

[0003] Chinese Patent with Publication No. CN105185669A discloses a gas protection device for a circuit breaker. It includes a closed cavity installed outside the housing of each phase of the circuit breaker. A sliding seat is arranged in the closed cavity. A piston structure is formed by the sliding fit between the sliding seat and the inner wall of the sealed cavity. The closed cavity has a vent hole located below the sliding seat. Each phase housing has a contact. The vent hole passes through one of the phase housings and communicates with the working cavity of the contact of this phase. The upper end of the sliding seat is connected with a push rod. The upper end of the push rod extends outside the closed cavity and can move up and down under the drive of the sliding seat. A tripping mechanism is installed on each phase housing, and the push rod can trigger the tripping mechanism. After adopting the above structure, once a short-circuit current generates airflow in a certain phase, the gas generated by the heat of the short-circuit current can push the sliding seat, and then drive the trigger mechanism to complete the tripping action through the push rod, realizing the opening of the switch. Its structural design is simple and ingenious, with a small volume and convenient installation. At the same time, the sealing performance is very good, which greatly improves the reliability of the action. However, this gas protection device for a circuit breaker itself is not an independent device. It needs to rely on the phase housings on both sides to form a closed cavity. Therefore, its replaceability is poor. In addition, a piston structure is formed by the sliding fit between the sliding seat and the inner wall of the sealed cavity. Its movement principle is that the gas pushes the sliding seat to move up and down, and the up and down movement of the sliding seat drives the push rod to move, and then drives the trigger mechanism to complete the tripping action. Since the gas thrust required for the sliding seat to move up and down is large, its action sensitivity is poor.

[0004] A Chinese patent with the publication number CN106601561B discloses a rotary pneumatic protection device for a plastic case circuit breaker. When in use, it is arranged between two adjacent phase contacts of the circuit breaker. The phase contacts are provided with a tripping mechanism and a traction rod, and the traction rod can trigger the tripping mechanism. The rotary pneumatic protection device includes a main housing, a cover plate, a rotary pressure rod and a sliding ejector rod. The main housing and the cover plate are tightly connected to form a sealed cavity. Vent holes for communicating with the working cavities of adjacent phase contacts are respectively provided on the main housing and the cover plate. The rotary pressure rod is arranged in the sealed cavity and rotates under the push of air flow. The sliding ejector rod is arranged in the main housing, its upper end extends outside the main housing, and its lower end contacts the rotary pressure rod. Moreover, the sliding ejector rod can only slide up and down under the constraint of the main housing structure. When the rotary pressure rod rotates, it drives the sliding ejector rod to move upward, pushing the traction rod to rotate and trigger the tripping mechanism to trip. This structure is independent and has sensitive action. However, its core design is a rotary pressure rod with a special curved surface. During the process of contacting and being used for a long time with the push rod, the curved surface characteristics are prone to wear, resulting in poor sensitivity, reduced service life, and it is difficult to control the stroke and force of the ejector rod. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a pneumatic protection device for a plastic case circuit breaker with controllable force and high safety.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A pneumatic protection device for a plastic case circuit breaker includes a base, a spring, an ejector rod, a slider and a cover plate. It is characterized in that three relatively independent ribs: rib a, rib b and rib c are provided on the base. The three ribs and the base together enclose two independent cavities: cavity a and cavity b. The slider is triangular, its top surface contacts the ejector rod, and a chute is provided between the lower two feet. The rib b is inserted into the chute, enabling the slider to move up and down along the rib b, and the two feet are respectively placed in cavity a and cavity b.

[0007] A vent hole a is provided on the base, and this vent hole a is located in cavity b.

[0008] The cover plate covers the base, seals cavity a and cavity b to form an independent chamber, and a vent hole b is provided on the cover plate, and this vent hole b is communicated with cavity a.

[0009] The cover plate has pins, and the pins are inserted into the base holes on the base to form a closed assembly.

[0010] The ejector rod includes a fixed block and two side feet. A rotating shaft is provided on the fixed block, and pin a and pin b are respectively provided on the two feet. The two ends of the rotating shaft are respectively inserted into the shaft hole a provided on the cover plate and the shaft hole b on the base, enabling the ejector rod to rotate around the base and the cover plate.

[0011] The pin a is cylindrical, inserted into the lower part of the spring. The upper part of the spring is fixed on the base. The top surface of the slider abuts against one leg of the ejector rod and pushes the leg to compress the spring, causing the ejector rod to rotate around the rotating shaft and driving the pin b to trigger the release mechanism.

[0012] The base is provided with a pin c, and the upper part of the spring is inserted into the pin c.

[0013] The outer sides of the two legs of the slider are respectively in contact with the rib a and the rib c, and the contact surfaces are arc-shaped. The middle parts between the two legs are respectively in contact with the rib b, and the bottom contact angle is arc-shaped, so that the friction force of the slider during movement is small.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) The present invention uses three independent ribs to form a closed assembly together with the cover plate on the base. A cavity for installing the ejector rod and the spring is provided on the upper base, and each component can be assembled independently.

[0016] (2) The present invention designs two independent closed cavities for the arc to enter. Each cavity is respectively provided with a vent hole for communicating with the working cavity of the adjacent phase contact. One vent hole is arranged on the ground base and one is arranged on the top cover plate. Therefore, whether there is a fault in the adjacent working chamber at the bottom or the adjacent working chamber at the top, a high-temperature and high-pressure conductive arc will be generated in the circuit. The arc enters the sealed cavity through the two vent holes, and can push the slider to move, driving the ejector rod to trigger the release mechanism, improving the safety of the product.

[0017] (3) The present invention uses the gas on both sides to push the same slider: the slider is a triangular structure, divided into a top connecting block and two side legs. The two side legs are respectively located in two sealed cavities and can move up and down along the middle rib. The gas in the two cavities can simultaneously push the same slider up and down, which is more stable and has higher sensitivity.

[0018] (4) The present invention uses the slider to push the ejector rod for tripping operation. The slider only moves up and down, driving the ejector rod to rotate, and the top surface of the slider is arc-shaped, with a large contact area and small wear between the slider and the ejector rod. Therefore, the stroke and force of the pneumatic device are both controllable. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram when the cover plate of the device of the present invention is covered;

[0020] Figure 2 It is a combined schematic diagram of the base and the cover plate;

[0021] Figure 3 It is a schematic structural diagram of the base;

[0022] Figure 4It is a schematic diagram of the cover plate structure;

[0023] Figure 5 It is a schematic diagram of the ejector rod structure;

[0024] Figure 6 It is a schematic diagram of the slider structure. Detailed implementation manners

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Embodiment 1

[0027] As Figure 1 shown, a pneumatic protection device for a plastic case circuit breaker includes a base 1, a spring 2, an ejector rod 3, a slider 4 and a cover plate 5.

[0028] Among them, the base 1, as Figure 3 shown, includes a sealed cavity and a receiving space provided above it. The sealed cavity is composed of a bottom base plate, a top cover plate and three relatively independent ribs inside. The three relatively independent ribs are: rib a11, rib b13 and rib c16. The three ribs and the base 1 together enclose two independent cavities: cavity a12 and cavity b14. The base 1 is provided with a ventilation hole a15, and the ventilation hole a12 is located in the cavity b14. The receiving space is used to install the ejector rod 3 and the spring 2, and is provided with a shaft hole b17, a pin c18 and a base hole 19 inside.

[0029] As Figure 4 shown, the cover plate 5 covers the base 1, seals the cavity a12 and the cavity b14 to form an independent chamber, and is provided with a ventilation hole b51 on the cover plate 5. The ventilation hole b51 communicates with the cavity a12. The cover plate 5 has pins 53, and the pins 53 are inserted into the base holes 19 on the base to fix the cover plate 5 on the base 1, thereby forming a closed assembly. As Figure 2 shown.

[0030] As Figure 5 shown, the ejector rod 3 includes a fixed block and two side feet. A rotating shaft 32 is provided on the fixed block, and pins a31 and pins b33 are respectively provided on the two feet. The two ends of the rotating shaft 32 are respectively inserted into the shaft hole a52 provided on the cover plate 5 and the shaft hole b17 on the base 1, so that the ejector rod 3 rotates around the base 1 and the cover plate 5. The pin a31 is in a cylindrical shape and is inserted into the lower part of the spring 2. The upper part of the spring 2 is inserted into the pin c18 of the base 1. The top surface 41 of the slider 4 abuts against one foot of the ejector rod 3 and pushes the foot to compress the spring 2, so that the ejector rod 3 rotates around the rotating shaft 32, driving the pin b33 to trigger the tripping mechanism.

[0031] As Figure 6As shown, the slider 4 is triangular. Its top surface 41 contacts the ejector rod 3. A chute 43 is provided between the lower two feet. The rib b13 is inserted into the chute 43, enabling the slider 4 to move up and down along the rib b13. The two feet are respectively placed in the cavity a12 and the cavity b14. The outer sides of the two feet of the slider 4 respectively contact the rib a11 and the rib c16, and the contact surface 42 is an arc surface. The middle parts of the two feet respectively contact the rib b13, and the bottom contact angle 44 is arc-shaped, so that the friction during the movement of the slider is small.

[0032] When a fault occurs in the circuit, a conductive arc with high temperature and high pressure will be generated in the circuit. The arc enters the sealed cavity (cavity a12 and cavity b14) through the vent hole a15 and the vent hole b51, pushing the slider 4 to move, and thus pushing the ejector rod 3 to complete the tripping action.

Claims

1. A pneumatic protection device for a molded case circuit breaker, comprising a base (1), a spring (2), a push rod (3), a slider (4) and a cover plate (5), characterized in that, The base (1) is provided with three relatively independent ribs: rib a (11), rib b (13) and rib c (16). The three ribs and the base (1) together enclose two independent cavities: cavity a (12) and cavity b (14). The slider (4) is triangular. Its top surface (41) contacts the ejector rod (3). A chute (43) is provided between the lower two feet. The rib b (13) is inserted into the chute (43) to enable the slider (4) to move up and down along the rib b (13). The two feet are respectively placed in the cavity a (12) and the cavity b (14). The base (1) is provided with a vent hole a (15), and the vent hole a (15) is located in the cavity b (14). The cover plate (5) covers the base (1) to seal the cavity a (12) and the cavity b (14) to form an independent chamber, and a vent hole b (51) is provided on the cover plate (5). The vent hole b (51) communicates with the cavity a (12). The ejector rod (3) includes a fixed block and two side feet. A rotating shaft (32) is provided on the fixed block. Pin a (31) and pin b (33) are respectively provided on the two side feet of the ejector rod (3). The two ends of the rotating shaft (32) are respectively inserted into the shaft hole a (52) on the cover plate (5) and the shaft hole b (17) on the base (1) so that the ejector rod (3) rotates around the base (1) and the cover plate (5). The pin a (31) is cylindrical and is inserted into the lower part of the spring (2). The upper part of the spring (2) is fixed on the base (1).

2. The pneumatic protection device of a molded case circuit breaker according to claim 1, characterized in that, The cover plate (5) has pins (53), and the pins (53) are inserted into the base holes (19) on the base to form a closed assembly.

3. The pneumatic protection device of a molded case circuit breaker according to claim 1, characterized in that, The top surface (41) of the slider (4) abuts against one foot of the ejector rod (3) and pushes the foot to compress the spring (2), so that the ejector rod (3) rotates around the rotating shaft (32), driving the pin b (33) to trigger the release mechanism.

4. The pneumatic protection device of a molded case circuit breaker according to claim 3, characterized in that, The base (1) is provided with a pin c (18), and the upper part of the spring (2) is inserted into the pin c (18).

5. The pneumatic protection device of a molded case circuit breaker according to claim 1, characterized in that, The outer sides of the two feet of the slider (4) are respectively in contact with the rib a (11) and the rib c (16). The contact surface (42) is an arc surface. The middle parts of the two feet are respectively in contact with the rib b (13), and the bottom contact angle (44) is arc-shaped.

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