Adjustable overload release for molded case circuit breaker
By combining a bimetallic strip with an adjusting screw, the distance between the bimetallic strip and the heating element can be adjusted, solving the problem of replacing the heating element material under different currents. This improves versatility and production efficiency, while also providing overload and short-circuit protection.
Patent Information
- Application Number
- CN202423265246.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2034-12-30
AI Technical Summary
Existing plastic-cased circuit breakers require thermal elements made of different materials for overload trip units to handle different currents, resulting in high production costs and poor versatility, which affects mass production efficiency.
It adopts a structure of bimetallic strip, adjusting screw and fixed iron core. The distance between the bimetallic strip and the thermal element can be adjusted by adjusting the adjusting screw to realize the overload tripping function under different currents. At the same time, it combines armature and spring structure to realize short circuit protection and avoid replacing the thermal element.
It enables the use of thermal elements without the need to replace them under different currents, adapts to different currents, reduces production costs, improves versatility, and has overload and short-circuit protection functions, thereby improving mass production efficiency.
Smart Images
Figure CN223927337U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit breaker technology, specifically to an adjustable overload trip unit for a plastic-cased circuit breaker. Background Technology
[0002] Overload adjustable molded case circuit breakers (MCCBs) on the market typically use a thermal element that heats up, causing the bimetallic strip to deform via conduction. This deformed strip pushes the traction rod or tripping clip, causing the main circuit breaker mechanism to trip and disconnect the main circuit. Different rated current products require thermal elements made of different materials. These thermal elements often use low-resistance alloy materials, which are expensive, affecting production costs and turnover. Furthermore, these thermal elements have poor versatility, requiring different alloy materials for different currents, reducing the efficiency of mass production. Utility Model Content
[0003] To address the aforementioned problems, the purpose of this utility model is to provide an adjustable overload trip unit for plastic-cased circuit breakers that does not require replacement of heating elements made of different materials, has good versatility, and can adapt to different currents.
[0004] The objective of this utility model is achieved through the following technical solution:
[0005] An adjustable overload trip unit for a plastic-cased circuit breaker includes a bimetallic strip, a connecting plate, an adjusting screw, and a heating element, a bracket, and a stationary core that are sequentially bonded and fixed together to form the trip unit body. The bimetallic strip is slidably disposed on one side of the trip unit body and can bend upon heating to push the main circuit breaker mechanism to complete the tripping action. A threaded hole is provided at the lower part of the bimetallic strip. The connecting plate is located on the other side of the trip unit body and its upper end is fixedly connected to the heating element. A stationary core screw hole is provided on the stationary core, and a stationary core limiting notch is provided on the side of the stationary core facing the bracket, directly opposite the threaded hole. The shank of the adjusting screw moves sequentially through the pre-set screw holes on the bracket and the heating element and is threadedly connected to the threaded hole. The head of the adjusting screw is rotatably disposed within the stationary core limiting notch and cannot move axially. A concave polygonal drive groove is provided on the side of the head of the adjusting screw facing the stationary core screw hole.
[0006] Furthermore, the heating element, the bracket, and the fixed iron core are sequentially attached and fixed together by rivets that sequentially penetrate the fixed iron core, the bracket, and the heating element to form the main body of the trip unit.
[0007] Furthermore, in order to adjust the distance between the bimetallic strip and the traction rod (a rotating structure used to drive the main mechanism of the circuit breaker to trip), an adjusting bolt is threaded onto the upper part of the bimetallic strip.
[0008] Furthermore, the bimetallic strip is slidably disposed on one side of the trip unit body through the following structure: two bimetallic strip cantilever arms are provided on both sides of the lower part of the bimetallic strip facing the trip unit body, located on both sides of the thermal element; two bracket clearance positions are provided on the bracket corresponding to the two bimetallic strip cantilever arms; and two fixed core limiting holes are provided on the fixed core corresponding to the two bimetallic strip cantilever arms. The bimetallic strip cantilever arms are slidably disposed sequentially in the corresponding bracket clearance positions and the corresponding fixed core limiting holes, with their ends extending out of the fixed core limiting holes.
[0009] Furthermore, in order to limit the sliding distance of the bimetallic strip, the present invention provides the following structure: the end of the bimetallic strip cantilever is provided with a limiting block that restricts the bimetallic strip cantilever from being completely retracted into the limiting hole of the fixed iron core, which is used to limit the maximum distance between the bimetallic strip and the heating element.
[0010] Furthermore, to limit the sliding distance of the bimetallic strip, this utility model provides another structure as follows: the adjustable overload trip unit for the plastic-cased circuit breaker also includes a limiting armature front wall plate. The limiting armature front wall plate is disposed on the side of the bimetallic strip facing away from the trip unit body, and is used to block the bimetallic strip, prevent the bimetallic strip from disengaging from the adjusting screw, limit the maximum distance between the bimetallic strip and the thermal element, and make the bimetallic strip only move back and forth between the trip unit body (thermal element).
[0011] Furthermore, to achieve short-circuit protection for the circuit breaker and limit the sliding distance of the bimetallic strip, this utility model provides the following structure: A support plate is provided on each side of the bracket facing the thermal element, and the two support plates are located on both sides of the bimetallic strip and the thermal element (enclosing the bimetallic strip and the thermal element within the bracket). In addition, the adjustable overload trip unit for the plastic-cased circuit breaker also includes a shaft, an armature, and a spring; the armature includes a front armature wall plate and a side armature wall plate; the front armature wall plate is located on the side of the bimetallic strip facing away from the trip unit body, used to block the bimetallic strip, prevent the bimetallic strip from detaching from the adjusting screw, and limit the maximum distance between the bimetallic strip and the thermal element; the side armature wall plates are two pieces, respectively fixed on both sides of the front armature wall plate, and the two side armature wall plates are respectively attached to the outside of the support plates on both sides of the bracket, one of which is the armature... The side wall plate extends upward to the position corresponding to the main mechanism of the circuit breaker and can push the main mechanism of the circuit breaker to complete the tripping action under the drive of the electromagnet, realizing the tripping function of the main mechanism of the circuit breaker in the event of a short circuit; the spring is located between the two support plates, one end of which is mounted on the wall plate and the other end is mounted on the bracket (the bracket plate has a pre-set bracket hook) for resetting the armature; the shaft is installed between the two support plates and its two ends pass outward through the two armature side wall plates respectively, and the shaft is located on the side of the bimetallic strip facing away from the main body of the trip unit.
[0012] Furthermore, the spring is a double torsion spring.
[0013] Furthermore, in order to enable the installation and positioning of the front wall plate of the armature, the lower part of the two support plates is provided with a lower hook corresponding to the front wall plate of the armature. The lower part of the front wall plate of the armature is set in the lower hook of the two support plates, and the front wall plate of the armature can swing back and forth in the lower hook.
[0014] This utility model has good adaptability and versatility, and can adapt to different currents. When the current changes, there is no need to replace the heating element with a different material, which will not affect production costs and turnover, nor will it reduce the efficiency of mass production. At the same time, this utility model also has overload trip protection and short circuit trip protection functions. Attached Figure Description
[0015] The structure of this utility model will be further described in detail below with reference to the accompanying drawings.
[0016] Figure 1 This is a schematic diagram of the adjustable overload trip unit for the plastic-cased circuit breaker described in this utility model.
[0017] Figure 2 This is an exploded structural diagram of the plastic-cased circuit breaker described in this utility model.
[0018] Figure 3 This is a schematic diagram of the structure of the bimetallic sheet described in this utility model.
[0019] Figure 4 This is a schematic diagram of the structure of the thermal element described in this utility model.
[0020] Figure 5 This is a schematic diagram of the structure of the connecting plate described in this utility model.
[0021] Figure 6 This is a schematic diagram of the structure of the bracket described in this utility model.
[0022] Figure 7 This is a schematic diagram of the structure of the adjusting screw described in this utility model.
[0023] Figure 8 This is a schematic diagram of the fixed iron core of this utility model.
[0024] Figure 9 This is a schematic diagram of the armature structure described in this utility model.
[0025] Figure 10 This is a schematic diagram of the structure of the spring described in this utility model.
[0026] Figure 11 This is a schematic diagram of the structure of the traction rod described in this utility model.
[0027] As shown in the diagram: 100-Bimetallic strip, 101-Upper threaded hole, 102-Lower threaded hole, 200-Heating element, 201-Heating element threaded hole, 202-Heating element welding surface, 203-Heating element rivet hole, 204-Heating element screw hole, 300-Adjusting bolt, 400-Connecting plate, 401-Connecting plate welding surface, 402-Connecting plate screw hole, 500-Shaft, 600-Bracket, 601-Bracket shaft hole, 602-Bracket screw hole, 603-Bracket lower hook, 604-Bracket upper hook, 605-Bracket rivet hole, 606-Bracket clearance, 607-Bracket plate, 700-Adjusting screw, 7 01-Adjusting screw head, 702-Polygonal drive groove, 800-Fixed iron core, 801-Fixed iron core limiting hole, 802-Fixed iron core side plate, 803-Fixed iron core limiting notch, 804-Fixed iron core rivet hole, 805-Fixed iron core screw hole, 900-Rivet, 1000-Armature, 1001-Armature shaft hole, 1002-Armature notch, 1003-Armature front wall plate, 1004-Armature side wall plate, 1005-Armature head, 1100-Spring, 1101-Spring first cantilever, 1102-Spring inner hole, 1103-Spring second cantilever, 1200-Traction rod, 1201-Traction rod release force surface. Detailed Implementation
[0028] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. The described embodiments are merely some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0029] In the description of this utility model, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" or "linked" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a mechanical connection or an electrical connection; it can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. It should be noted that the terms "comprising," "including," or any other variations are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Example 1
[0030] like Figure 1 and Figure 2As shown, this embodiment provides an adjustable overload trip unit for a plastic-cased circuit breaker, including a bimetallic strip 100, a heating element 200, an adjusting bolt 300, a connecting plate 400, a bracket 600, an adjusting screw 700, a fixed iron core 800, and rivets. The heating element 200, the bracket 600, and the fixed iron core 800 are sequentially attached and fixed together to form the trip unit body.
[0031] like Figure 1 and Figure 3 As shown, the bimetallic strip 100 is slidably disposed on the side of the trip unit body near the thermal element 200, and slides back and forth along the direction away from or near the thermal element 200. After being heated (receiving heat from the thermal element 200), the bimetallic strip 100 bends and pushes the tripping force surface 1201 of the traction rod 1200, causing the traction rod 1200 to swing. After the traction rod 1200 swings, it pushes the main mechanism of the circuit breaker to complete the tripping action. The upper part of the bimetallic strip 100 corresponds to the position of the tripping force surface 1201 of the traction rod and is provided with an upper threaded hole 101. The adjusting bolt 300 is threadedly connected to the upper threaded hole 101 on the upper part of the bimetallic strip 100. The lower part of the bimetallic strip 100 is provided with a lower threaded hole 102. On both sides of the lower part of the bimetallic strip 100 facing the trip unit body, there are two bimetallic strip cantilever 103 located on both sides of the thermal element 200. The bimetallic strip 100 has a conventional structure. Its passive layer faces the release force surface 1201 of the traction rod, and the active layer is connected to the thermal element 200. The active layer is mainly made of manganese-nickel-copper alloy, nickel-chromium-iron alloy, nickel-manganese-iron alloy, and nickel, etc. The passive layer is mainly made of nickel-iron alloy with a nickel content of 34-50%.
[0032] like Figure 1 and Figure 4 As shown, the thermal element 200 is located on the side of the trip unit body facing the bimetallic strip 100. A thermal element welding surface 202 for welding the connecting plate 400 is provided on the upper part of the thermal element 200 facing away from the bimetallic strip 100. A thermal element screw hole 204 is provided on the lower part of the thermal element 200 directly opposite the lower threaded hole 102. At the same time, a thermal element rivet hole 203 is also provided on the lower part of the thermal element 200. An installation plate is integrally fixed to the bottom of the thermal element 200 and mounted on the MCCB base. The installation plate is provided with a thermal element threaded hole 201. The screw spirals through the thermal element threaded hole 201 to install the thermal element 200 on the MCCB base. The thermal element 200 transfers heat to the bimetallic strip 100 by radiation.
[0033] like Figure 1 and Figure 5As shown, the connecting plate 400 is located on the other side of the trip unit body near the fixed iron core 800, and its upper end is fixedly connected to the heating element 200. The upper part of the connecting plate 400, facing the heating element welding surface 202 of the heating element 200, has a connecting plate welding surface 401. The connecting plate 400 is welded to the heating element welding surface 202 of the heating element 200 through the connecting plate welding surface 401, thus achieving a fixed connection between the two. A connecting plate screw hole 402 is provided at the bottom of the connecting plate 400. A screw spirals through the connecting plate screw hole 402, mounting the connecting plate 400 onto the MCCB base.
[0034] like Figure 1 and Figure 6 As shown, the bracket 6 is fixedly attached to the side of the heating element 200 facing away from the bimetallic strip 100 and located below the connecting plate 400. A bracket screw hole 602 is provided on the bracket 600 directly opposite the threaded hole 102, and a bracket rivet hole 605 is provided on the bracket 600 directly opposite the rivet hole 203 of the heating element. A bracket plate 607 is provided on each side of the bracket 600 facing the heating element 200. The two bracket plates 607 are located on both sides of the bimetallic strip 100 and the heating element 200, surrounding the bimetallic strip 100 and the heating element 200 within the bracket 600. A bracket shaft hole 601 is provided on both bracket plates 607, and a bracket hook 604 is also provided on the upper part of the side of the bracket plate 607 facing away from the bimetallic strip 100. Two bracket clearance positions 606 are provided on the bracket 600, corresponding one-to-one with the two bimetallic strip cantilever 103, allowing the bimetallic strip cantilever 103 to slide back and forth along the bracket clearance positions 606.
[0035] like Figure 1 and Figure 8 As shown, the fixed iron core 800 is attached and fixed to the side wall of the bracket 6 facing away from the heat element 200. A fixed iron core screw hole 805 is provided on the fixed iron core 800 directly opposite the lower threaded hole 102, and a fixed iron core rivet hole 804 is provided on the fixed iron core 800 directly opposite the bracket rivet hole 605. Simultaneously, a fixed iron core limiting notch 803 communicating with the fixed iron core screw hole 805 is provided on the side of the fixed iron core 800 facing the bracket 600, directly opposite the lower threaded hole 102 (concave). Two fixed iron core limiting holes 801 are provided on the fixed iron core 800, corresponding one-to-one with the two bimetallic cantilever arms. The bimetallic cantilever arms 103 are sequentially slidably disposed in the corresponding bracket clearance 606 and the corresponding fixed iron core limiting hole 801, with their ends extending out of the fixed iron core limiting hole 801. Thin-walled fixed iron core side plates 802 are provided on both sides of the fixed iron core 800 for limiting the fixed iron core side plates 802.
[0036] like Figure 1 and Figure 7As shown, the shank of the adjusting screw 700 passes sequentially through the pre-set screw holes (screw hole 602 on the bracket and screw hole 204 on the heating element 200) on the bracket 600 and then is threaded into the lower threaded hole 102. The head of the adjusting screw 700 (i.e., the adjusting screw head 701) is rotatably positioned within the fixed core limiting notch 803, directly opposite the fixed core screw hole 805, and cannot move axially. The adjusting screw 700 drives the bimetallic strip 100 to move closer to or further away from the heating element 200 through forward and reverse axial rotation. The distance between the bimetallic strip 100 and the heating element 200 is adjustable. A concave polygonal drive groove 702 is provided on the side of the head of the adjusting screw 700 (adjusting screw head 701) facing the fixed iron core screw hole 805. The polygonal drive groove 702 is an internal hexagonal hole and is directly opposite the fixed iron core screw hole 805 (connected to and aligned with the fixed iron core screw hole 805). The diameter of the outer circle of the polygonal drive groove 702 is smaller than the diameter of the fixed iron core screw hole 805, and the diameter of the fixed iron core screw hole 805 is smaller than the head diameter of the adjusting screw 700.
[0037] After the heating element 200, the bracket 600 and the fixed iron core 800 are attached together in sequence, they are then riveted together by rivets 900 that pass through the rivet holes 804 of the fixed iron core, 605 of the bracket and 203 of the heating element to form the main body of the trip unit.
[0038] The assembly steps are as follows:
[0039] During assembly, the connecting plate welding surface 401 of the connecting plate 400 and the heating element welding surface 202 of the heating element 200 are welded together to form the main circuit in the trip unit; the adjusting screw 700 is pre-placed between the bracket screw hole 602 and the limiting notch 803 of the fixed iron core 800; the rivet 900 passes through the heating element rivet hole 203, the bracket rivet hole 605, and the fixed iron core rivet hole 804 to fix the three together to form the trip unit body; the bimetallic strip cantilever 103 at the lower part of the bimetallic strip 100 passes through the bracket clearance 606 and the fixed iron core limiting hole 801 in sequence; the shank (threaded end) of the adjusting screw 700 passes through the bracket screw hole 602 and the heating element screw in sequence. After hole 204 is connected to the lower threaded hole 102 of bimetallic strip 100 by using an internal hexagonal adjusting screwdriver (the internal hexagonal adjusting screwdriver passes through the fixed core screw hole 805 and extends into the polygonal drive groove 702, driving the adjusting screw 700 to rotate and screw into the lower threaded hole 102), forming an adjustable distance function with the trip unit body. Then, the adjusting bolt 300 is installed at the upper threaded hole 101 of bimetallic strip 100 to form an overload trip structure. Finally, the trip unit is installed in the MCCB base by using screws through the thermal element threaded hole 201 and the connecting plate threaded hole 402. The fixed core side plates 802 on both sides of the fixed core 800 are synchronously limited in the corresponding features of the base.
[0040] The working principle is as follows:
[0041] The overload current in the MCCB main circuit flows through the thermal element 200 of the trip unit, generating a large amount of heat. The thermal element 200 transfers the heat energy to the bimetallic strip 100 through radiation. The bimetallic strip 100 bends due to the heat (bending towards the tripping force surface 1201 of the traction rod 1200), causing the traction rod 1200 to rotate. The traction rod 1200 drives the MCCB main mechanism to complete the tripping action, achieving the overload protection function.
[0042] In this embodiment, the distance between the bimetallic strip 100 and the heating element 200 is adjustable. Without changing the materials of the bimetallic strip 100 and the heating element 200, by adjusting the distance between the bimetallic strip 100 and the heating element 200, the heat generated by different overload currents passing through the heating element 200 is always transferred to the bimetallic strip 100 with constant energy, causing the bimetallic strip 100 to bend and push the traction rod 1200 to rotate, thus completing the MCCB tripping function. Example 2
[0043] To limit the sliding distance of the bimetallic strip 100, this embodiment adds the following settings based on embodiment 1.
[0044] The end of the bimetallic strip cantilever 103 is provided with a limiting block to restrict the bimetallic strip cantilever 103 from being fully retracted into the fixed iron core limiting hole 801, which is used to limit the maximum distance between the bimetallic strip 100 and the heating element 200. By setting the limiting block, the maximum distance between the bimetallic strip 100 and the heating element 200 is limited, preventing the bimetallic strip 100 from disengaging from the adjusting screw 700. Example 3
[0045] To limit the sliding distance of the bimetallic strip 10, this embodiment adds another structure based on embodiment 1.
[0046] The adjustable overload trip unit for the plastic-cased circuit breaker also includes a limiting armature front wall plate 1003. The limiting armature front wall plate 1003 is disposed on the side of the bimetallic strip 100 facing away from the trip unit body, and is used to block the bimetallic strip 100, prevent the bimetallic strip 100 from disengaging from the adjusting screw 700, limit the maximum distance between the bimetallic strip 100 and the heating element 200, and make the bimetallic strip 100 only move back and forth between the limiting armature front wall plate 1003 and the trip unit body (heating element 200); the limiting armature front wall plate 1003 is provided with a clearance hole for supporting the end of the rod of the adjusting screw 700. Example 4
[0047] To achieve short-circuit protection for the circuit breaker and limit the sliding distance of the bimetallic strip 100, this embodiment adds the following settings based on embodiment 1.
[0048] The adjustable overload trip unit for the plastic-cased circuit breaker also includes a shaft 500, an armature 1000, and a spring 1100.
[0049] like Figure 1 and Figure 9 As shown, the armature 1000 includes an armature front wall plate 1003 and an armature side wall plate 1004. The armature front wall plate 1003 is located on the side of the bimetallic strip 100 facing away from the trip unit body, and is used to block the bimetallic strip 100, prevent the bimetallic strip 100 from disengaging from the adjusting screw 700, limit the maximum distance between the bimetallic strip 100 and the heating element 200, and has a clearance hole on the armature front wall plate 1003 to support the rod of the adjusting screw 700. The armature side wall plate 1004 consists of two pieces, which are respectively fixed on both sides of the armature front wall plate 1003, and the two armature side wall plates 1004 are respectively attached to the supports on both sides of the bracket 600. Outside the bracket 607 (and capable of relative rotation), one of the armature sidewall plates 1004 extends upward to form an armature head 1005 corresponding to the position of the main mechanism of the circuit breaker. The armature 1000 can rotate towards the traction rod tripping force surface 1201 of the traction rod 1200 under the drive of an electromagnet, so that the armature head 1005 contacts the traction rod tripping force surface 1201 and pushes the traction rod 1200 to rotate, thereby causing the traction rod 1200 to push the main mechanism of the circuit breaker to complete the tripping action, realizing the function of tripping the main mechanism of the circuit breaker in the event of a short circuit. The armature front wall plate 1003 and the armature sidewall plate 1004 surround the main body of the trip unit. The armature front wall plate 1003 is provided with an armature notch 1002, and the two armature sidewall plates 1004 are provided with armature shaft holes 1001. All armature shaft holes 1001 and all bracket shaft holes 601 are located on the same straight line.
[0050] like Figure 1 and Figure 10 As shown, the spring 1100 is located between two support plates 607. The spring 1100 is a double torsion spring used for the reset of the armature 1000. It has a first spring cantilever 1101, a spring inner hole 1102, and a second spring cantilever 1103. The first spring cantilever 1101 of the spring 1100 is installed on a hook 604 on a bracket pre-set on the support plate 607, and the second spring cantilever 1103 of the spring 1100 is installed in the armature notch 1002 of the armature front wall plate 1003.
[0051] like Figure 1 As shown, the shaft 500 is installed between two support plates 607 (both ends of the shaft 500 are located inside the support shaft holes 601), and both ends of the shaft 500 pass outward through the armature shaft holes 1001 on the two armature sidewall plates 1004. The shaft 500 is located on the side of the bimetallic strip 100 facing away from the trip unit body. During a short circuit, the armature 1000 rotates around the shaft 500, causing its upper end to rotate towards or away from the tripping force surface 1201 of the traction rod.
[0052] The shaft 500, armature 1000, spring 1100, and electromagnet constitute a short-circuit tripping structure. During installation, the shaft 500 passes through the armature shaft hole 1001, the bracket shaft hole 601, and the spring inner hole 1102. The first cantilever 1101 of the spring is placed at the hook 604 on the bracket, and the second cantilever 1103 of the spring is placed at the armature notch 1002, thus forming the short-circuit tripping structure. When the MCCB main circuit is short-circuited, the electromagnet coil generates a magnetic field that pushes the movable iron core, which is movably sleeved in the coil, to move towards the armature 1000, causing the armature 1000 to rotate. This causes the armature head 1005 to rotate towards the tripping force surface 1201 of the traction rod 1200, thereby pushing the traction rod 1200 to rotate and causing the traction rod 1200 to push the main mechanism of the circuit breaker to complete the tripping action.
[0053] The short-circuit tripping structure is mounted on the overload tripping structure via shaft 500, forming a complete overload and short-circuit trip unit. The short-circuit tripping structure and the overload tripping structure coexist in parallel without interfering with each other. Example 5
[0054] In order to achieve the installation and limiting of the armature front wall plate 1003 on the armature 1000, the following settings are added to this embodiment based on embodiment 4.
[0055] The lower part of the two support plates 607 is provided with a support hook 603 corresponding to the armature front wall plate 1003. The lower part of the armature front wall plate 1003 is set in the support hook 603 of the two support plates 607, and the armature front wall plate 1003 can swing back and forth in the support hook 603.
[0056] Other aspects of this utility model that are not detailed herein are all conventional techniques known to those skilled in the art.
[0057] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0058] The scope of protection of this utility model is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this utility model shall fall within the scope of protection of this utility model.
Claims
1. An adjustable overload trip unit for a plastic-cased circuit breaker, characterized in that: The trip unit includes a bimetallic strip (100), a connecting plate (400), an adjusting screw (700), and a heat element (200), a bracket (600), and a fixed iron core (800) that are sequentially attached and fixed together to form the main body of the trip unit. The bimetallic strip (100) is slidably disposed on one side of the trip unit body and can bend after being heated to push the main mechanism of the circuit breaker to complete the tripping action. A threaded hole (102) is provided at the lower part of the bimetallic strip (100). The connecting plate (400) is located on the other side of the trip unit body and its upper end is fixedly connected to the heat element (200). A fixed iron core screw is provided on the fixed iron core (800). The pin hole (805) and the fixed iron core limiting notch (803) are provided on the side of the fixed iron core (800) facing the bracket (600) and directly opposite the lower threaded hole (102); the rod of the adjusting screw (700) moves through the screw holes preset on the bracket (600) and the heating element (200) in sequence and is threaded to the lower threaded hole (102); the head of the adjusting screw (700) is rotatably set in the fixed iron core limiting notch (803) and cannot move axially; a concave polygonal drive groove (702) is provided on the side of the head of the adjusting screw (700) facing the fixed iron core screw hole (805).
2. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 1, characterized in that: The thermal element (200), bracket (600) and fixed iron core (800) are sequentially attached and fixed together by rivets (900) that sequentially penetrate the fixed iron core (800), bracket (600) and thermal element (200) to form the main body of the trip unit.
3. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 1, characterized in that: An adjusting bolt (300) is threaded onto the upper part of the bimetallic strip (100).
4. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 1, characterized in that: Two bimetallic strip cantilever arms (103) are provided on both sides of the lower part of the bimetallic strip (100) facing the main body of the trip unit. Two bracket clearance positions (606) are provided on the bracket (600) corresponding to the two bimetallic strip cantilever arms (103). At the same time, two fixed core limiting holes (801) are provided on the fixed core (800) corresponding to the two bimetallic strip cantilever arms. The bimetallic strip cantilever arms (103) are slidably arranged in the corresponding bracket clearance positions (606) and the corresponding fixed core limiting holes (801) in sequence, and their ends extend out of the fixed core limiting holes (801).
5. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 4, characterized in that: The end of the bimetallic strip cantilever (103) is provided with a limiting block that restricts the bimetallic strip cantilever (103) from being completely retracted into the fixed iron core limiting hole (801).
6. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 1, characterized in that: It also includes a limiting armature front wall plate (1003), which is disposed on the side of the bimetallic strip (100) facing away from the trip unit body.
7. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 1, characterized in that: A bracket plate (607) is provided on each side of the bracket (600) facing the heat element (200), and the two bracket plates (607) are located on both sides of the bimetallic sheet (100) and the heat element (200).
8. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 7, characterized in that: It also includes a shaft (500), an armature (1000), and a spring (1100); the armature (1000) includes an armature front wall plate (1003) and an armature side wall plate (1004); the armature front wall plate (1003) is located on the side of the bimetallic strip (100) facing away from the trip unit body; the armature side wall plate (1004) consists of two pieces and is fixed to both sides of the armature front wall plate (1003), and the two armature side wall plates (1004) are respectively attached to the outside of the bracket plates (607) on both sides of the bracket (600), one of which is an armature front wall plate (1100). The iron sidewall plate (1004) extends upward to the position corresponding to the main mechanism of the circuit breaker and can push the main mechanism of the circuit breaker to complete the tripping action under the drive of the electromagnet; the spring (1100) is located between the two support plates (607), one end of which is installed on the wall plate (1003) and the other end is installed on the bracket (600); the shaft (500) is installed between the two support plates (607) and its two ends pass outward through the two armature sidewall plates (1004), and the shaft (500) is located on the side of the bimetallic strip (100) facing away from the main body of the trip unit.
9. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 8, characterized in that: The spring (1100) is a double torsion spring.
10. The adjustable overload trip unit for a plastic-cased circuit breaker according to claim 8, characterized in that: The lower part of the two support plates (607) is provided with a support hook (603) corresponding to the armature front wall plate (1003). The lower part of the armature front wall plate (1003) is set in the support hook (603) of the two support plates (607), and the armature front wall plate (1003) can swing back and forth in the support hook (603).