Contact pressure control mechanism and molded case circuit breaker

Abstract

The invention relates to a contact pressure control mechanism and a molded case circuit breaker. The contact pressure control mechanism comprises a contact support; one end of the movable contact bridge is rotationally connected with the contact support, and the other end of the movable contact bridge is close to and attached to the static contact bridge along with forward rotation or far away from the static contact bridge along with reverse rotation; the movable contact bridge is provided with a sliding end; the lever is rotationally arranged on the contact support and comprises a first limiting surface and a second limiting surface which are obliquely connected; the sliding end abuts against the first limiting face and the second limiting face in a sliding mode. Two ends of the contact spring are respectively connected with the lever and the contact support, so that the second limiting surface abuts against the sliding end and provides forward rotation torque for the movable contact bridge during closing; and when the movable contact bridge is separated, the movable contact bridge rotates reversely. The anti-falling device has the anti-falling capability after the moving contact bridge is repelled, the moment borne by the moving contact bridge in the repelling process is stable, the repelling speed is high, the current limiting capability is high, and the short-circuit protection capability of the circuit breaker is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit protection equipment, in particular to a contact pressure control mechanism and a molded case circuit breaker. BACKGROUND

[0002] The molded case circuit breaker is used in AC or DC low-voltage power grid for switching on and off current, and its structure generally comprises an operating mechanism, an arc extinguishing system, a contact system, a housing, and a trip unit, wherein the contact system is an important part and plays an important role in reliability and breaking capacity.

[0003] The switching on of the contact system of the molded case circuit breaker is completed through the contact of the moving contact bridge and the static contact bridge, and the contact support is internally provided with a contact spring, which provides the contact force between the moving contact and the static contact during closing. The moving contact bridge has a certain overtravel to ensure the reliability of the contact. In the on state, the electrodynamic repulsion force is generated between the moving contact and the static contact. When the short-circuit current is generated, the electrodynamic repulsion force increases sharply, and the moving contact bridge quickly overcomes the spring force of the contact spring to separate the moving contact and the static contact under the action of the electrodynamic repulsion force. However, in this process, the spring force increases with the separation distance, and the moving contact bridge falls after rotating an angle and recontacts the static contact bridge. This action occurs multiple times before the operating mechanism performs the tripping action, thereby multiple arcs are generated to damage the moving contact and the static contact, and even the moving contact and the static contact are welded together and cannot be opened, and the circuit breaker loses the basic protection function.

[0004] The existing patent CN102427001A discloses a contact pressure control mechanism of a molded case low-voltage circuit breaker, which generates the contact pressure by the contact spring against the front side of the upper end of the lever and then the rear side of the upper end of the lever applies force to the moving contact bridge. The two continuous surfaces of the rear side of the upper end of the lever have a certain angle. In the process of repelling and clamping the moving contact bridge, the lever will deflect greatly around the shaft of the lower end, and the spring will also be twisted and deformed, so that the spring force will be reduced, affecting the reliability and service life of the circuit breaker. SUMMARY

[0005] The present application aims to overcome the defects of the existing molded case circuit breaker, such as easy damage and short service life, and provides a contact pressure control mechanism and a molded case circuit breaker.

[0006] The purpose of the present application can be achieved by the following technical solutions.

[0007] One of the technical solutions of the present application is to provide a contact pressure control mechanism, comprising:

[0008] a contact support;

[0009] A movable contact bridge is rotatably connected to one end of the contact support, and is close to the static contact bridge and adheres to it with forward rotation, or is away from the static contact bridge with reverse rotation. A sliding end is arranged on the movable contact bridge.

[0010] A lever is rotatably arranged on the contact support, and includes a first limiting surface and a second limiting surface which are obliquely connected. The sliding end is slidably abutted on the first limiting surface and the second limiting surface.

[0011] A contact spring is connected to the lever and the contact support at both ends, and can drive the lever to rotate reversely, so that

[0012] When the switch is closed, the second limiting surface is abutted with the sliding end, and a forward rotation torque of the movable contact bridge is provided. When the short-circuit current is large enough to repel the movable contact bridge and the static contact bridge, and the circuit breaker has not triggered the trip, the movable contact bridge reversely rotates, the sliding end slides from the second limiting surface to the first limiting surface, the first limiting surface is abutted with the sliding end, and a reverse rotation torque of the movable contact bridge is provided.

[0013] In some specific embodiments, a first hole groove is arranged on the contact support, a first through hole is arranged on the movable contact bridge, a first connecting shaft passes through the first through hole of the movable contact bridge and penetrates into the first hole groove, so that the movable contact bridge rotates around the first connecting shaft with the contact support.

[0014] In some specific embodiments, a third hole groove is arranged on the contact support, a lever through hole is arranged on the lever, a second connecting shaft passes through the lever through hole and penetrates into the third hole groove, so that the contact support rotates around the second connecting shaft with the lever.

[0015] In some specific embodiments, the axis of the third hole groove is parallel to the axis of the first hole groove.

[0016] In some specific embodiments, a third limiting surface is arranged on the contact support to limit the reverse rotation of the movable contact bridge.

[0017] In some specific embodiments, a second through hole is arranged at the bottom of the movable contact bridge, a sliding shaft passes through the second through hole, and the end of the sliding shaft slides along the second limiting surface and the first limiting surface.

[0018] In some specific embodiments, a spring hole is arranged on the lever for fixing one end of the contact spring.

[0019] In some specific embodiments, a second hole groove is arranged on the contact support, the other end of the contact spring is sleeved on a third connecting shaft, and the third connecting shaft also penetrates into the second hole groove.

[0020] In some embodiments, the axis of the second hole slot is parallel to the axis of the first hole slot of the contact support, and the spring hole is also directed toward the second hole slot.

[0021] The second technical solution of the present application provides a molded case circuit breaker, comprising the contact pressure control mechanism of any one of the above technical solutions, and comprising a housing accommodating the contact pressure control mechanism, wherein the housing is used to limit the reverse rotation of the movable contact bridge to reset the movable contact bridge when the molded case circuit breaker is tripped.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] (1) The present application has stable torque on the movable contact bridge during repulsion, fast repulsion speed, and strong current limiting capacity. When the repulsion reaches a certain angle, the torque provided by the contact spring decreases to 0, which improves the repulsion speed and is beneficial to the short-circuit protection capacity of the circuit breaker.

[0024] (2) The present application has the ability to prevent the movable contact bridge from falling after repulsion, reduces the contact wear during breaking, and improves the service life of the molded case circuit breaker.

[0025] (3) The present application uses a tension spring as the contact spring, and the spring always remains straight during the movement of the movable contact bridge under the repulsion of the electric force, which does not twist and improves the service life of the spring and the reliability of the circuit breaker.

[0026] (4) In the present application, the lever applies force to the movable contact bridge through the riveting shaft, which has a reliable structure and strong durability.

[0027] (5) The present application is a contact pressure control mechanism that can be used for multiple movable contact bridges, and has good short-time withstand capacity. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structure schematic diagram of the present application when the contact is closed;

[0029] Figure 2 is a structure schematic diagram of the present application when the contact is opened;

[0030] Figure 3 is a structure schematic diagram of the present application when the contact is repulsed;

[0031] Figure 4 is a sectional structure schematic diagram of the contact support in the present application;

[0032] Figure 5 is a structure schematic diagram of the lever in the present application;

[0033] Figure 6 is a structure schematic diagram of the movable contact bridge in the present application;

[0034] Figure 7 is a part of the internal structure of the present application;

[0035] Figure 8 is a schematic diagram of force and force arm when closing the switch of the present application;

[0036] Figure 9 is a schematic diagram of force and force arm when opening the switch of the present application.

[0037] The figures are identified as follows:

[0038] 1 is a contact support, 11 is a first hole slot, 12 is a second hole slot, 13 is a third hole slot, 14 is a third limiting surface, 2 is a moving contact bridge, 21 is a first through hole of the moving contact bridge, 22 is a top surface, 23 is a second through hole of the moving contact bridge, 3 is a first connecting shaft, 4 is a lever, 41 is a first limiting surface, 42 is a second limiting surface, 43 is a through hole of the lever, 44 is a spring hole, 5 is a contact spring, 6 is a third connecting shaft, 7 is a second connecting shaft, 8 is a sliding shaft, 9 is a static contact bridge, and 10 is an outer shell. DETAILED DESCRIPTION

[0039] The present application will be described in detail below with reference to the drawings and specific embodiments. The present embodiment is implemented on the basis of the technical solution of the present application, and gives a detailed implementation and specific operation process, but the protection scope of the present application is not limited to the following embodiments.

[0040] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0041] Some embodiments of the present application will be described in detail below with reference to the drawings. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

[0042] In the following embodiments, if there is no special description of the function components or structures, it means that they are all conventional components or conventional structures adopted in the art to realize the corresponding functions.

[0043] Embodiment 1:

[0044] As Figures 1-7As shown, the embodiment provides a contact pressure control mechanism, which comprises a contact support 1; a movable contact bridge 2, one end of which is rotatably connected to the contact support 1, and the other end approaches the static contact bridge 9 and is attached thereto with forward rotation, or moves away from the static contact bridge 9 with reverse rotation; the movable contact bridge 2 is provided with a sliding end; a lever 4 is rotatably arranged on the contact support 1 and comprises a first limiting surface 41 and a second limiting surface 42 which are connected in an inclined manner; the sliding end is slidably abutted on the first limiting surface 41 and the second limiting surface 42; a contact spring 5 is connected to the lever 4 and the contact support 1 at both ends and can drive the lever 4 to rotate reversely, so that when the circuit breaker is closed, the second limiting surface 42 is abutted with the sliding end, and a forward rotation torque of the movable contact bridge 2 is provided; when the short-circuit current is large enough to repel the movable contact bridge 2 and the static contact bridge 9, and the circuit breaker has not been triggered to trip, the movable contact bridge 2 rotates reversely, the sliding end slides from the second limiting surface 42 to the first limiting surface 41, the first limiting surface 41 is abutted with the sliding end, and a reverse rotation torque of the movable contact bridge 2 is provided.

[0045] By the embodiment, when the contact pressure control mechanism is closed, the contact spring 5 applies a torque to the movable contact bridge 2 through the lever 4, thereby providing a contact pressure to stably contact the movable contact bridge 2 with the static contact bridge 9, that is, the contact spring 5 applies a clockwise torque to the movable contact bridge 2 through the lever 4, thereby providing a forward rotation torque of the movable contact bridge 2, the movable contact bridge 2 contacts the second limiting surface 42, and the contact pressure when the circuit breaker is closed is provided.

[0046] When the short-circuit current is large enough to repel the movable contact bridge 2 and the static contact bridge 9, and the circuit breaker has not been tripped, an electrodynamic repulsion force is generated between the movable contact bridge 2 and the static contact bridge 9, and the movable contact bridge 2 rotates under the action of the electrodynamic repulsion force. When the movable contact bridge 2 rotates to a certain angle, the direction of the force of the lever 4 on the movable contact bridge 2 changes, the direction of the torque of the contact spring 5 on the movable contact bridge 2 changes, and the movable contact bridge 2 rotates to a state of being clamped by the contact support 1 and the lever 4. At this time, the movable contact bridge 2 reaches a repelled state. That is, a huge electrodynamic repulsion force is generated at the position where the movable contact bridge 2 contacts the static contact bridge 9, so that the movable contact bridge 2 separates from the static contact bridge 9. At this time, the movable contact bridge 2 rotates counterclockwise and is separated from the second limiting surface 42, and the direction of the torque of the contact spring 5 on the movable contact bridge 2 through the lever 4 changes from clockwise to counterclockwise, thereby providing a reverse rotation torque of the movable contact bridge 2. At this time, the contact pressure control mechanism is in a repelled state. Since the direction of the torque of the lever 4 on the movable contact bridge 2 is counterclockwise, the movable contact bridge 2 is subjected to the contact pressure for preventing falling after being repelled, which can effectively improve the current limiting capability and accelerate the breaking speed, reduce the contact wear during breaking, and improve the service life of the molded case circuit breaker.

[0047] When the short-circuit current is large enough to make the moving contact bridge 2 and the static contact bridge 9 repel, the circuit breaker triggers the tripping action, and the contact pressure control mechanism rotates counterclockwise as a whole, so that the moving contact bridge 2 collides with the limiting surface, such as the packaging shell of the contact pressure control mechanism. Under the limiting action of the limiting surface, the moving contact bridge 2 overcomes the counterclockwise torque in the repelled state and rotates clockwise relative to the contact support 1, so that the rebound can be reset.

[0048] In the present embodiment, the contact support 1 and the moving contact bridge 2, and the contact support 1 and the lever 4 are rotationally connected through connecting shafts. For example, a first hole slot 11 is formed in the contact support 1, a first moving contact bridge through hole 21 is formed in the moving contact bridge 2, a first connecting shaft 3 passes through the first moving contact bridge through hole 21 and penetrates into the first hole slot 11, so that the moving contact bridge 2 rotates around the first connecting shaft 3 with the contact support 1. A third hole slot 13 is formed in the contact support 1, a lever through hole 43 is formed in the lever 4, a second connecting shaft 7 passes through the lever through hole 43 and penetrates into the third hole slot 13, so that the contact support 1 rotates around the second connecting shaft 7 with the lever 4. In addition, the axis of the third hole slot 13 is parallel to the axis of the first hole slot 11, so that the rotation plane of the moving contact bridge 2 is parallel to the rotation plane of the lever 4.

[0049] The second limiting surface 42 is arranged perpendicular to the horizontal plane, and the first limiting surface 41 is inclined towards the direction of the static contact bridge 9, so that the moving contact bridge 2 can rely on the slope of the first limiting surface 41 when moving away from the second limiting surface 42 in the opposite direction. The first limiting surface 41 and the second limiting surface 42 are transitioned by a circular arc, so that the torque change of the moving contact bridge 2 is smooth, thereby making the repelling of the contact pressure control mechanism smooth and rapid.

[0050] The contact support 1 is provided with a third limiting surface 14 for limiting the reverse rotation of the moving contact bridge 2. On the one hand, it limits the maximum angle of reverse rotation of the moving contact bridge 2 to avoid affecting the service life of the contact spring 5; on the other hand, it is also to ensure that the moving contact bridge 2 can be limited to the appropriate position to complete the reset by rebounding when the contact pressure control mechanism is tripped.

[0051] Therefore, when the short-circuit current is large enough to make the moving contact bridge 2 and the static contact bridge 9 repel, but the circuit breaker has not tripped, the moving contact bridge 2 is under the action of the electric repulsion force, and the torque direction of the contact spring 5 applied to the moving contact bridge 2 through the lever 4 changes from clockwise to counterclockwise, that is, the reverse rotation torque of the moving contact bridge 2 is provided, and finally the third limiting surface 14 on the contact support 1 abuts against the top surface 22 of the moving contact bridge 2, at which time the contact pressure control mechanism is in the repelled state.

[0052] When the short-circuit current is sufficient to cause the moving contact bridge 2 and the stationary contact bridge 9 to open, triggering the circuit breaker's tripping action, the entire contact pressure control mechanism rotates counterclockwise. The moving contact bridge 2 touches the limiting surface, such as the outer casing of the contact pressure control mechanism, and rebounds to its initial position after being limited by the limiting surface. That is, under the limiting action of the limiting surface, the moving contact bridge 2 overcomes the counterclockwise torque in the open state and rebounds clockwise relative to the contact support 1, thus contacting the second limiting surface 42 again, and the moving contact bridge 2 is reset.

[0053] To enhance the smoothness and durability of the sliding between the movable bridge 2 and the lever 4, in this embodiment, the bottom of the movable bridge 2 is provided with a second through hole 23. A sliding shaft 8 passes through the second through hole 23, and the end of the sliding shaft 8 serves as a sliding end that slides along the second limiting surface 42 and the first limiting surface 41. The sliding shaft 8 can be riveted to the second through hole 23 of the movable bridge to form a riveted shaft. The lever 4 applies force to it through the riveted shaft of the movable bridge 2, resulting in a reliable structure and high durability.

[0054] In this embodiment, the contact spring 5 is a tension spring, and the lever 4 has a spring hole 44 for fixing one end of the contact spring 5. The contact support 1 has a second slot 12, and the other end of the contact spring 5 is sleeved on the third connecting shaft 6, which also passes through the second slot 12.

[0055] Since the first slot 11 connects the contact support 1 and the moving contact bridge 2, and the spring hole 44 connects the lever 4 and the contact spring 5, and the axis of the second slot 12 is parallel to the axis of the first slot 11, and the spring hole 44 is also oriented towards the second slot 12, the contact support 1, the contact spring 5 and the lever 4 can work together on the moving contact bridge 2, and the contact spring 5 remains straight during operation and will not be twisted, thereby improving the service life of the contact spring 5 and the reliability of the molded case circuit breaker.

[0056] Therefore, in the contact pressure control mechanism of this embodiment 1, when the contact pressure control mechanism is in the closed state, the sliding shaft 8 at the bottom of the moving contact bridge 2 contacts the second limiting surface 42 of the lever 4, and the contact spring 5 applies a clockwise torque to the moving contact bridge 2 through the lever 4, providing the contact pressure during closing. Figure 8 The diagram shows the acceptance and lever arm of the closed state. F1 is the force exerted by the contact spring 5 on the lever 4, and L1 is the lever arm of F1 relative to the rotation center of the lever 4; F2 is the force exerted by the lever 4 on the moving contact bridge 2, and L2 is the lever arm of F2 relative to the rotation center of the lever 4; L3 is the lever arm of F2 relative to the rotation center of the moving contact bridge 2; F3 is the force exerted by the stationary contact bridge 9 on the moving contact bridge 2, and L4 is the lever arm of F3 relative to the rotation center of the moving contact bridge 2.

[0057] When the short-circuit current is large enough to repel the moving contact bridge 2 and the static contact bridge 9, but the circuit breaker has not tripped, a huge electrodynamic repulsion force is generated at the position where the moving contact bridge 2 and the static contact bridge 9 are in contact, the moving contact bridge 2 and the static contact bridge 9 are separated, the moving contact bridge 2 rotates counterclockwise around the axis of the first hole groove 11 (i.e. the first connecting shaft 3), the sliding shaft 8 slides from the second limit surface 42 to the first limit surface 41, at this time the direction of the torque exerted on the moving contact bridge 2 by the contact spring 5 through the lever 4 changes from clockwise to counterclockwise, and finally the third limit surface 14 on the contact support 1 abuts against the top surface 22 of the moving contact bridge 2, at this time the contact pressure control mechanism is in a repulsion state.

[0058] When the short-circuit current is large enough to repel the moving contact bridge 2 and the static contact bridge 9, but the circuit breaker has not tripped, a huge electrodynamic repulsion force is generated at the position where the moving contact bridge 2 and the static contact bridge 9 are in contact, the moving contact bridge 2 and the static contact bridge 9 are separated, the moving contact bridge 2 rotates counterclockwise around the axis of the first hole groove 11 (i.e. the first connecting shaft 3), the sliding shaft 8 slides from the second limit surface 42 to the first limit surface 41, at this time the direction of the torque exerted on the moving contact bridge 2 by the contact spring 5 through the lever 4 changes from clockwise to counterclockwise, and finally the third limit surface 14 on the contact support 1 abuts against the top surface 22 of the moving contact bridge 2, at this time the contact pressure control mechanism is in a repulsion state.

[0059] Figure 9 For the force and arm diagram of the repulsion state, during the repulsion process, first the sliding shaft 8 will slide from the second limit surface 42 to the first limit surface 41, the lever 4 rotates clockwise by a small angle, at this time the contact spring 5 is elongated, the spring force F1 increases, at the same time the position of the spring hole 44 changes, the direction of the force of the contact spring 5 changes, the torque L1 decreases, during the upward sliding of the sliding shaft 8, the sliding shaft 8 is away from the rotation center of the lever 4, the arm L2 increases, the angle of the force F2 of the lever 4 on the sliding shaft 8 changes, the arm L3 decreases. Under the changes of the arms L1, L2 and L3, although the spring force F1 gradually increases, the torque acting on the moving contact bridge 2 changes little, that is, during this process, the rotating torque acting on the moving contact bridge 2 is stable. When the sliding shaft 8 slides through the transition surface from the second limit surface 42 to the first limit surface 41, the arm L3 will gradually decrease to 0 and then gradually increase, the contact surface of the sliding shaft 8 and the lever 4 changes to the first limit surface 41, at this time the force of the lever 4 on the moving contact bridge 2 is counterclockwise relative to the rotation center of the moving contact bridge 2, the moving contact bridge 2 rotates counterclockwise to the position where the top surface 22 abuts against the third limit surface 14, at this time the contact pressure control mechanism is in a repulsion state. During the process of the sliding shaft 8 passing through the transition surface, when the arm L3 is 0, the moving contact bridge 2 is not affected by the force of the contact spring 5, therefore the repulsion speed of the moving contact bridge 2 is accelerated, which is helpful to the current limiting and arc extinguishing ability.

[0060] Example 2:

[0061] The present embodiment provides a molded case circuit breaker, comprising the contact pressure control mechanism of embodiment 1, a housing 10 accommodating the contact pressure control mechanism, when the molded case circuit breaker is tripped, the housing 10 is used to limit the reverse rotation of the movable contact bridge 2 to reset it.

[0062] When the line is short-circuited to trigger tripping, the contact pressure control mechanism rotates counterclockwise as a whole, so that the movable contact bridge 2 collides with the housing 10, and under the limiting action of the housing 10, the movable contact bridge 2 rebounds, overcomes the counterclockwise torque in the repulsion state, rotates clockwise relative to the contact support 1, so that the rebound is reset.

[0063] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art within the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A contact pressure control mechanism, characterized in that, include: Contact support (1); The moving contact bridge (2) has one end rotatably connected to the contact support (1), and the other end moves closer to and fits against the stationary contact bridge (9) as it rotates in the forward direction, or moves away from the stationary contact bridge (9) as it rotates in the reverse direction; the moving contact bridge (2) is provided with a sliding end; The lever (4) is rotatably mounted on the contact support (1) and includes a first limiting surface (41) and a second limiting surface (42) that are inclined to be connected; the sliding end slides against the first limiting surface (41) and the second limiting surface (42); The contact spring (5) is connected at both ends to the lever (4) and the contact support (1) respectively, and can drive the lever (4) to rotate in the opposite direction so that... When the circuit is closed, the second limiting surface (42) abuts against the sliding end and provides the moving contact bridge (2) with a positive rotational torque; when the short-circuit current is large enough to cause the moving contact bridge (2) and the stationary contact bridge (9) to repel each other, and the circuit breaker has not yet triggered tripping, the moving contact bridge (2) rotates in the opposite direction, and the sliding end slides from the second limiting surface (42) to the first limiting surface (41), the first limiting surface (41) abuts against the sliding end and provides the moving contact bridge (2) with a reverse rotational torque.

2. The contact pressure control mechanism according to claim 1, characterized in that, The contact support (1) has a first slot (11), and the movable contact bridge (2) has a first through hole (21). The first connecting shaft (3) passes through the first through hole (21) and into the first slot (11), so that the movable contact bridge (2) and the contact support (1) rotate around the first connecting shaft (3).

3. The contact pressure control mechanism according to claim 2, characterized in that, The contact support (1) has a third slot (13), and the lever (4) has a lever through hole (43). The second connecting shaft (7) passes through the lever through hole (43) and into the third slot (13), so that the contact support (1) and the lever (4) rotate around the second connecting shaft (7).

4. The contact pressure control mechanism according to claim 3, characterized in that, The axis of the third slot (13) is parallel to the axis of the first slot (11).

5. The contact pressure control mechanism according to claim 1, characterized in that, The contact support (1) is provided with a third limiting surface (14) to restrict the reverse rotation of the moving contact bridge (2).

6. The contact pressure control mechanism according to claim 1, characterized in that, The bottom of the movable bridge (2) is provided with a second through hole (23), and a sliding shaft (8) passes through the second through hole (23). The end of the sliding shaft (8) is used as the sliding end to slide along the second limiting surface (42) and the first limiting surface (41).

7. The contact pressure control mechanism according to claim 1, characterized in that, The lever (4) has a spring hole (44) for fixing one end of the contact spring (5).

8. The contact pressure control mechanism according to claim 7, characterized in that, The contact support (1) has a second slot (12), and the other end of the contact spring (5) is sleeved on the third connecting shaft (6). The third connecting shaft (6) also passes through the second slot (12).

9. The contact pressure control mechanism according to claim 8, characterized in that, The axis of the second slot (12) is parallel to the axis of the first slot (11) of the contact support (1), and the spring hole (44) is also oriented toward the second slot (12).

10. A molded case circuit breaker comprising a contact pressure control mechanism as described in any one of claims 1-9, characterized in that, The circuit breaker includes a housing (10) that houses the contact pressure control mechanism. When the molded case circuit breaker trips, the housing (10) is used to limit the reverse rotation of the moving contact bridge (2) so that it resets.

Images