Contact bistable switching control mechanism of a thermal relay and thermal relay

Abstract

This utility model discloses a bistable switching control mechanism for a thermal relay contact and the thermal relay itself. The mechanism includes a housing, a movable spring push rod movably mounted on the housing, a switching rod corresponding to the movable spring push rod, and an actuating spring connected to the movable spring push rod. The movable spring push rod has a minimum bistable switching travel corresponding to the shear dead point of the thermal relay's actuating spring. The switching rod has a switchable limiting position and a releasing position relative to the housing. The movable spring push rod and the switching rod are respectively provided with a first limiting part and a second limiting part. When the switching rod is pushed to the limiting position, the second limiting part moves into the movement path of the first limiting part and engages with the first limiting part when the movable spring push rod actuates, limiting the travel of the movable spring push rod to less than the minimum bistable switching travel. This utility model utilizes the switching rod to manually control whether the contacts perform bistable switching, thus expanding the application range of the thermal relay.

Description

Technical Field

[0001] This utility model relates to the field of thermal relay technology, specifically to a contact bistable switching control mechanism for a thermal relay and a thermal relay. Background Technology

[0002] Although thermal relays are also called relays, they differ significantly from conventional relays. Specifically, a relay is an electrical component that activates its contacts when an input signal (current, voltage, temperature, etc.) reaches a set value, enabling circuit switching, control, amplification, or isolation. A thermal relay, however, utilizes only the principle of current heating and is specifically designed for overload protection of motors or electrical equipment. It provides protection against "long-term overload" to prevent damage from continuous overcurrent. Existing thermal relays have a moving spring push rod connected to the contacts and an actuating spring that drives the push rod. The actuating spring has a shear dead point; after passing this dead point under external force, it cannot return to its initial state due to its own elasticity. Based on this, the actuating spring, under external force, can move the moving spring push rod, which in turn controls the contacts to perform bistable switching (normally open to normally closed or normally closed to normally open). However, existing thermal relays do not allow manual control of whether the contacts perform bistable switching, limiting their application. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a contact bistable switching control mechanism for thermal relays. It mainly solves the technical problem that existing thermal relays cannot be manually controlled to switch contacts in a bistable state, thus limiting their application.

[0004] To achieve the above objectives, this utility model is implemented through the following technical solution: A bistable switching control mechanism for a thermal relay includes a housing, a movable spring push rod movably mounted on the housing, a switching rod corresponding to the movable spring push rod, and an actuating spring connected to the movable spring push rod. The movable spring push rod has a minimum bistable switching travel corresponding to the shear dead point of the actuating spring of the thermal relay. The switching rod has a switchable limiting position and a releasing position relative to the housing. The movable spring push rod and the switching rod are respectively provided with a first limiting part and a second limiting part. When the switching rod is pushed to the limiting position, the second limiting part moves into the movement path of the first limiting part and can cooperate with the first limiting part to limit the travel of the movable spring push rod to less than the minimum bistable switching travel when the movable spring push rod is actuated.

[0005] Furthermore, when the switching lever is reset to the release limit position, the second limit part exits the movement path of the first limit part, thereby releasing the restriction on the movement stroke of the moving spring push rod, so that the movement stroke of the moving spring push rod is greater than the minimum movement stroke of the bistable switching, so that the thermal relay action spring can pass its shear dead point under the action of external force.

[0006] Furthermore, the switching lever has a handle that protrudes from the housing.

[0007] Furthermore, the moving spring push rod is provided with a snap-fit ​​groove, and the end of the thermal relay actuating spring is snapped into the snap-fit ​​groove, thereby enabling the moving spring push rod and the thermal relay actuating spring to form a linkage.

[0008] Furthermore, the snap-fit ​​groove is provided with a left clearance slope and a right clearance slope that correspond to the left and right swing direction of the thermal relay action spring during bistable switching.

[0009] Furthermore, the inner wall of the snap-fit ​​groove is provided with a left arc protrusion and a right arc protrusion that are arranged opposite to each other. The end of the thermal relay actuating spring is adapted to snap into the gap between the left arc protrusion and the right arc protrusion, thereby making the end of the thermal relay actuating spring form a point contact with the inner wall of the snap-fit ​​groove.

[0010] Based on the same inventive concept, this utility model also provides a thermal relay, including a contact bistable switching control mechanism of any of the thermal relays described above. The thermal relay also includes a main circuit load monitoring system, an action mechanism transmission system, and an auxiliary signal output system. The main circuit load monitoring system includes a bimetallic element and a contact plate. The auxiliary signal output system includes a moving spring push rod, an NC auxiliary contact, and a NO auxiliary contact. The moving spring push rod is configured to connect with the moving springs of the NC auxiliary contact and the NO auxiliary contact and drive the two moving springs to move synchronously. The action mechanism transmission system includes a guide plate structure, a compensating bimetallic element, an action push rod support, a switching action mechanism assembly, a setting current knob, and an action mechanism knob.

[0011] The above technical solution has the following advantages or beneficial effects:

[0012] In the bistable switching control mechanism and thermal relay of this utility model, the switching rod has a switchable limiting position and a release position relative to the housing, and the moving spring push rod and the switching rod are respectively provided with a first limiting part and a second limiting part. Thus, the switching rod can be manually pushed to move to the preset limiting position. At this time, the second limiting part will enter the movement path of the first limiting part. Under the action of external force, the thermal relay actuating spring swings and drives the moving spring push rod to move until the first limiting part and the second limiting part form a limiting engagement, and the movement stroke of the moving spring push rod is limited to less than the minimum movement stroke of bistable switching. Thus, the limiting engagement formed by the first limiting part and the second limiting part restricts the swing amplitude of the thermal relay actuating spring and prevents it from crossing the shear dead point, so that the contact structure of the thermal relay does not perform bistable switching. When the external force disappears, the thermal relay actuating spring resets under its own elastic force and drives the moving spring push rod back to the initial state position. When needed, the switching lever can be manually pushed to move it from the limiting position to the released position, so that the second limiting part exits the movement path of the first limiting part. In this way, under the action of external force, the thermal relay actuating spring can drive the moving spring push rod to swing. Since the stroke of the moving spring push rod is no longer restricted by the second limiting part, the thermal relay actuating spring can swing past the shear dead point under the action of external force, and then drive the corresponding contact moving spring to perform bistable switching through the moving spring push rod. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the thermal relay according to an embodiment of the present invention.

[0014] Figure 2 This is another structural schematic diagram of the thermal relay according to an embodiment of the present utility model.

[0015] Figure 3 This is a schematic diagram of the contact bistable switching control mechanism according to an embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram of the cooperation structure between the moving spring push rod and the switching rod in an embodiment of this utility model (in the state of releasing the limiting cooperation).

[0017] Figure 5 This is a schematic diagram of the cooperation structure between the moving spring push rod and the switching rod in an embodiment of this utility model (forming a limiting cooperation state).

[0018] Figure 6 This is a schematic diagram of the cooperation structure between the moving spring push rod and the actuating spring sheet in an embodiment of this utility model.

[0019] Figure 7 yes Figure 6 A magnified view of section A in the image.

[0020] Figure 8 This is a schematic diagram of another angle of engagement between the moving spring push rod and the actuating spring sheet in an embodiment of this utility model.

[0021] Figure 9 This is a schematic diagram of another angle-fitting structure between the moving spring push rod and the actuating spring sheet in an embodiment of this utility model.

[0022] Figure 10 This is an exploded three-dimensional structural diagram of the thermal relay according to an embodiment of the present invention.

[0023] Figure 11 This is an exploded three-dimensional structural diagram of the thermal relay according to another embodiment of the present invention.

[0024] Figure 12 This is a schematic diagram of the internal structure of the thermal relay according to an embodiment of the present invention.

[0025] Figure 13 This is another internal structural diagram of the thermal relay according to an embodiment of the present invention.

[0026] Label Explanation:

[0027] 1. Housing; 2. Spring push rod; 3. Switching rod; 4. Action spring; 5. NC auxiliary contact; 6. NO auxiliary contact; 7. Main circuit load monitoring system; 8. Action mechanism transmission system; 9. Auxiliary signal output system; 21. First limiting part; 22. Snap-fit ​​groove; 31. Second limiting part; 32. Handle; 41. Shear dead point; 221. Left clearance slope; 222. Right clearance slope; 223. Left arc protrusion; 224. Right arc protrusion. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] Please refer to the appendix. Figure 1 To be continued Figure 13One embodiment of this utility model provides a contact bistable switching control mechanism for a thermal relay (a contact bistable switching control mechanism refers to a control mechanism used to control the contact structure of a thermal relay to switch from a normally open structure to a normally closed structure or from a normally closed structure to a normally open structure), including a housing 1, a movable spring push rod 2 movably disposed on the housing 1 (in this embodiment, the movable spring push rod 2 is configured to connect with the movable springs of the NC auxiliary contact 5 and the NO auxiliary contact 6 and drive the two movable springs to move synchronously), a switching rod 3 corresponding to the movable spring push rod 2, and an actuating spring 4 connected to the movable spring push rod 2. The movable spring push rod 2 has a shear dead point 41 corresponding to the actuating spring 4 of the thermal relay. The corresponding bistable switching minimum travel distance, the switching rod 3 has a switchable limiting position and a releasing position relative to the housing 1, the moving spring push rod 2 and the switching rod 3 are respectively provided with a first limiting part 21 and a second limiting part 31, and when the switching rod 3 is pushed to the limiting position, the second limiting part 31 moves into the movement path of the first limiting part 21, and can cooperate with the first limiting part 21 to limit the movement distance of the moving spring push rod 2 to less than the bistable switching minimum travel distance (the bistable switching minimum travel distance refers to the movement distance of the moving spring push rod 2 from the starting point to when the thermal relay action spring 4 just swings to the shear dead point). Furthermore, when the switching lever 3 returns to the released limit position, the second limit part 31 exits the movement path of the first limit part 21, thereby releasing the restriction on the travel of the moving spring push rod 2, making the travel of the moving spring push rod 2 greater than the minimum travel of the bistable switching, so that the thermal relay operating spring 4 can pass its shear dead point 41 under the action of external force. Furthermore, the switching lever 3 has a handle 32 exposed outside the housing 1.

[0031] It is understood that in this embodiment, since the switching lever 3 has a switchable limiting position and a releasing position relative to the housing 1, and the moving spring push rod 2 and the switching lever 3 are respectively provided with a first limiting part 21 and a second limiting part 31, the switching lever 3 can be manually pushed to move to the preset limiting position. At this time, the second limiting part 31 will enter the movement path of the first limiting part 21. Under the action of external force, the thermal relay actuating spring 4 swings and drives the moving spring push rod 2 to move until the first limiting part 21 and the second limiting part 31 form a limiting engagement. (The moving spring push rod 2 is restricted from continuing to move in the direction of increasing stroke, but the moving spring push rod 2 is not restricted from resetting.) The stroke of the moving spring push rod 2 is restricted to be less than the minimum stroke of the bistable switching. Thus, the first limiting part 21 and the second limiting part 31 form a limiting cooperation to restrict the swing amplitude of the thermal relay operating spring 4 and prevent it from crossing the shear dead point. As a result, the contact structure of the thermal relay does not perform bistable switching. When the external force disappears, the thermal relay operating spring 4 resets under its own elastic force and drives the moving spring push rod 2 back to the initial position. When needed, the switching lever 3 can be manually pushed out of the limiting position to the released position, causing the second limiting part 31 to exit the movement path of the first limiting part 21. Under external force, the thermal relay actuating spring 4 can drive the moving spring push rod 2 to swing. Since the stroke of the moving spring push rod 2 is no longer restricted by the second limiting part 31, the thermal relay actuating spring 4 can swing past the shear dead point 41 under external force, thereby driving the corresponding contact moving spring to perform bistable switching via the moving spring push rod 2. Thus, the switching lever 3 allows manual control of whether the contacts perform bistable switching, expanding the application range of the thermal relay.

[0032] Please refer to the appendix. Figure 1 To be continued Figure 9In one preferred embodiment, the moving spring push rod 2 is provided with a locking groove 22, and the end of the thermal relay actuating spring 4 is locked in the locking groove 22, thereby making the moving spring push rod 2 and the thermal relay actuating spring 4 linked together. Preferably, the locking groove 22 is provided with a left clearance slope 221 and a right clearance slope 222 corresponding to the left and right swing direction of the thermal relay actuating spring 4 during bistable switching. Further, the inner wall of the locking groove 22 is provided with a left arc protrusion 223 and a right arc protrusion 224 arranged opposite to each other, and the end of the thermal relay actuating spring 4 is adapted to be locked in the gap between the left arc protrusion 223 and the right arc protrusion 224, thereby making the end of the thermal relay actuating spring 4 form a point contact with the inner wall of the locking groove 22. In this embodiment, since there is a certain structural elastic deformation when the thermal relay actuating spring 4 switches between the two states, that is, the end portion of the thermal relay actuating spring 4 that engages with the locking groove 22 is inclined at a certain angle, the provision of a left clearance slope 221 and a right clearance slope 222 in the locking groove 22, corresponding to the left and right swing direction of the thermal relay actuating spring 4 during bistable switching, can improve the compatibility between the locking groove 22 and the thermal relay actuating spring 4. At the same time, the end of the thermal relay actuating spring 4 is adapted to engage in the gap between the left arc protrusion 223 and the right arc protrusion 224, so that the end of the thermal relay actuating spring 4 forms a point contact engagement with the inner wall of the locking groove 22, which can reduce the friction between the thermal relay actuating spring 4 and the locking groove 22, and improve the smoothness of movement and displacement accuracy of the moving spring push rod 2.

[0033] Please refer to the appendix. Figure 1 To be continued Figure 9An embodiment of this utility model also provides a thermal relay, including the contact bistable switching control mechanism of any of the thermal relays described above. Preferably, the thermal relay further includes a main circuit load monitoring system 7, an actuation mechanism transmission system 8, and an auxiliary signal output system 9. The main circuit load monitoring system 7 includes a bimetallic element 71 and a contact plate 72. The auxiliary signal output system 9 includes a moving spring push rod 2, an NC auxiliary contact 5, and a NO auxiliary contact 6. The moving spring push rod 2 is configured to connect with the moving springs of the NC auxiliary contact 5 and the NO auxiliary contact 6 and drive the two moving springs to move synchronously. The actuation mechanism transmission system 8 includes a guide plate structure 81, a compensating bimetallic element 82, an actuation push rod support 83, a switching actuation mechanism assembly 84, a setting current knob 85, and an actuation mechanism knob 86. Specifically, the working principle is as follows: the bimetallic element in the main circuit load monitoring system 7 is connected in series with the load circuit, and the thermal element on the outside of the bimetallic element causes the bimetallic sheet to expand and bend under the thermal effect of the current. When the load is under overload or phase loss abnormal conditions, the bimetallic strip increases its bending deflection, which actuates the bistable actuating spring in the trigger mechanism transmission system 8 to switch its actuation. The actuating spring pulls the moving spring push rod in the auxiliary signal output system 9 to switch the state of the NO auxiliary contact and NC auxiliary contact, outputting an electrical signal.

[0034] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model. Therefore, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

Claims

1. A contact bistable switching control mechanism for a thermal relay, characterized by: The device includes a housing (1), a spring push rod (2) movably mounted on the housing (1), a switching rod (3) corresponding to the spring push rod (2), and an action spring (4) connected to the spring push rod (2). The spring push rod (2) has a bistable switching minimum travel corresponding to the shear dead point (41) of the thermal relay action spring (4). The switching rod (3) has a switchable limiting position and a releasing position relative to the housing (1). The spring push rod (2) and the switching rod (3) are respectively provided with a first limiting part (21) and a second limiting part (31). When the switching rod (3) is pushed to the limiting position, the second limiting part (31) moves into the movement path of the first limiting part (21) and can cooperate with the first limiting part (21) when the spring push rod (2) moves to limit the travel of the spring push rod (2) to less than the bistable switching minimum travel.

2. The contact bistable switching control mechanism of a thermal relay according to claim 1, characterized by: When the switching lever (3) is reset to the release limit position, the second limit part (31) exits the movement path of the first limit part (21), thereby releasing the travel limit on the moving spring push rod (2), so that the travel of the moving spring push rod (2) is greater than the minimum travel of the bistable switching, so that the thermal relay action spring (4) can pass its shear dead point (41) under the action of external force.

3. The contact bistable switching control mechanism of a thermal relay according to claim 1, characterized by: The switching lever (3) has a handle (32) exposed outside the housing (1).

4. The contact bistable switching control mechanism of the thermal relay according to any one of claims 1 to 3, characterized in that: The moving spring push rod (2) is provided with a snap-fit ​​groove (22), and the end of the thermal relay actuating spring (4) is snapped into the snap-fit ​​groove (22), thereby making the moving spring push rod (2) and the thermal relay actuating spring (4) linked together.

5. The contact bistable switching control mechanism of the thermal relay according to claim 4, characterized in that: The slot (22) is provided with a left clearance slope (221) and a right clearance slope (222) that correspond to the left and right swing direction of the thermal relay action spring (4) during bistable switching.

6. The contact bistable switching control mechanism of the thermal relay according to claim 4, characterized in that: The inner wall of the snap-fit ​​groove (22) is provided with a left circular arc protrusion (223) and a right circular arc protrusion (224) arranged opposite to each other. The end of the thermal relay actuating spring (4) is adapted to snap into the gap between the left circular arc protrusion (223) and the right circular arc protrusion (224), thereby making the end of the thermal relay actuating spring (4) form a point contact with the inner wall of the snap-fit ​​groove (22).

7. A thermal relay, characterized in that: The contact bistable switching control mechanism of the thermal relay as described in any one of claims 1 to 6.

8. The thermal relay according to claim 7, characterized in that: The thermal relay also includes a main circuit load monitoring system (7), an action mechanism transmission system (8), and an auxiliary signal output system (9).

9. The thermal relay according to claim 8, characterized in that: The auxiliary signal output system (9) includes a moving spring push rod (2), an NC auxiliary contact (5) and a NO auxiliary contact (6). The moving spring push rod (2) is configured to connect with the moving springs of the NC auxiliary contact (5) and the NO auxiliary contact (6) and drive the two moving springs to move synchronously.

10. The thermal relay according to claim 8, characterized in that: The main circuit load monitoring system (7) includes a bimetallic element (71) and a contact plate (72), and the action mechanism transmission system (8) includes a guide plate structure (81), a compensating bimetallic element (82), an action push rod support (83), a switching action mechanism assembly (84), a setting current knob (85), and an action mechanism knob (86).

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