Circuit breaker including tapered drive shaft section

Abstract

The circuit breaker includes: a detachable contact; a drive shaft coupled to the detachable contact and configured to move the detachable contact to open and close; a tapered drive shaft section coupled to the drive shaft and having a tapered surface; and a friction assembly. The friction assembly includes: a friction device configured to interact with the tapered surface of the tapered drive shaft; an armature coupled to the friction device; and a biasing member configured to bias the friction device and the armature toward the tapered drive shaft section.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Patent Application No. 18 / 132,620, filed on April 10, 2023, entitled "CIRCUIT INTERRUPTER WITH TAPERED DRIVE SHAFT SECTION", the disclosure of which is incorporated herein by reference.

[0002] The disclosed concept generally relates to circuit breakers, and more particularly, to damping mechanisms and latching mechanisms in circuit breakers.

Background Art

[0003] Circuit breakers (e.g., but not limited to, circuit breakers, etc.) are typically used to protect electrical circuits from damage due to over - current conditions caused by overload conditions, short - circuits, or other fault conditions such as arc faults or ground faults. Circuit breakers typically include separable electrical contacts that function as switches. When the separable electrical contacts are in contact with each other in the closed state, current can flow through the circuit connected to the circuit breaker. When the separable electrical contacts are in contact with each other in the open state, current cannot flow through the circuit connected to the circuit breaker. The separable electrical contacts can be manually operated using an operating handle, remotely operated using an electrical signal, or automatically operated in response to a detected fault condition. Typically, such circuit breakers include an actuator designed to quickly open and close the separable electrical contacts and a trip mechanism such as a trip unit that senses a plurality of fault conditions and automatically opens the separable electrical contacts using the actuator. When a fault condition is sensed, the trip unit trips the actuator and moves the separable electrical contacts to the open position.

[0004] For example, some circuit breakers, such as power circuit breakers, employ vacuum circuit breakers as switching devices. The detachable electrical contacts typically included in a vacuum circuit breaker are generally located at the ends of corresponding electrodes within an insulating housing that forms a vacuum chamber. Typically, one contact is fixed to both the housing and an external electrical conductor electrically connected to the power circuit associated with the vacuum circuit breaker. The other contact is part of a movable contact assembly that includes a circular cross-section electrode stem and a contact located at one end of the electrode stem and housed within the vacuum chamber. The drive mechanism is located at the other end outside the vacuum chamber. When a trip unit detects a fault condition, it trips an actuator, causing the drive mechanism to open the detachable contact in the vacuum chamber. When the fault condition is resolved, the trip unit signals the actuator, causing the drive mechanism to close the detachable contact in the vacuum chamber.

[0005] In particular, in medium and high-voltage electrical systems, circuit breaker actuators need to be able to quickly drive the detachable contacts to the open position in order to mitigate the effects of fault conditions. Conventional embodiments have used overtoggle mechanisms including springs to achieve latching functions for the closing contact force and the open contact position. Oil-filled shock absorbers have also been used to suppress high-speed operation when the contacts open. However, overtoggle mechanisms and shock absorbers are bulky and lack scalability. As the rating of the circuit breaker increases, the size of these components can increase rapidly. Furthermore, overtoggle mechanisms have reliability issues and are at risk of returning to the closed contact position.

[0006] Thus, there is room for improvement in circuit breakers. [Overview of the project]

[0007] According to one aspect of the disclosed concept, a circuit breaker includes: a detachable contact; a drive shaft coupled to the detachable contact and configured to move the detachable contact to open and close; a tapered drive shaft section coupled to the drive shaft and having a tapered surface; and a friction assembly, the friction assembly including: a friction device configured to interact with the tapered surface of the tapered drive shaft; an armature coupled to the friction device; and a biasing member configured to bias the friction device and the armature toward the tapered drive shaft section.

[0008] According to one aspect of the disclosed concept, a circuit breaker includes: a detachable contact; a drive shaft coupled to the detachable contact and configured to move the detachable contact to open and close; a tapered drive shaft section coupled to the drive shaft and having a tapered surface; a latch arm assembly; the latch arm assembly includes a latch arm configured to rotate about a pivot point and having an upper end extending beyond the upper end of the tapered drive shaft section; and a spring-loaded latch; the latch is configured to extend to prevent it from rotating beyond a predetermined point in one direction.

[0009] According to one aspect of the disclosed concept, a circuit breaker includes: a detachable contact; a drive shaft coupled to the detachable contact and configured to move the detachable contact to open and close; a tapered drive shaft section coupled to the drive shaft and having a tapered surface and a grooved surface; and a ratchet assembly. The ratchet assembly includes: a gear configured to interact with the grooved surface of the tapered drive shaft section to allow movement in a first direction and to prevent movement in the opposite second direction; and a spring-loaded latch configured to interact with the gear to allow rotation in a first direction and to prevent rotation in the opposite second direction. [Brief explanation of the drawing]

[0010] The present invention can be fully understood by reading the following description of preferred embodiments in conjunction with the attached drawings. [Figure 1A] This is a perspective view of a circuit breaker. [Figure 1B] Figure 1A is an elevation view of a circuit breaker. [Figure 2A] This is a perspective view of a circuit breaker including a tapered drive shaft section, according to an exemplary embodiment of the disclosed concept. [Figure 2B] Figure 2A shows the circuit breaker in the state where the detachable contacts are in the closed position. [Figure 2C] Figure 2A is a detailed view of the tapered drive shaft section of the circuit breaker, showing the state in which the detachable contacts are in the open position. [Figure 3A] This is an elevation view of a circuit breaker including a tapered drive shaft section that provides a latching function according to an exemplary embodiment of the disclosed concept. [Figure 3B] Figure 3A is a detailed view of the tapered drive shaft section of the circuit breaker, showing the state in which the detachable contacts are in the open position. [Figure 3C] Figure 3A is a detailed view of the tapered drive shaft section of the circuit breaker, showing the state in which the detachable contacts are latched in the open position. [Figure 4A] This is a perspective view of a circuit breaker including a tapered drive shaft section and a latch arm according to an exemplary embodiment of the disclosed concept. [Figure 4B] Figure 4A is an elevation view of the circuit breaker, showing the state in which the detachable contacts are in the closed position. [Figure 4C] Figure 4A is an elevation view showing the circuit breaker in the state where the detachable contacts are latched in the open position. [Figure 5A] This is a perspective view of a circuit breaker including a tapered drive shaft section and a ratchet latch mechanism, according to an exemplary embodiment of the disclosed concept. [Figure 5B] Figure 5A is an elevation view of a circuit breaker. [Modes for carrying out the invention]

[0011] The terms used herein to indicate direction, such as up, down, left, right, upper side, lower side, front, back, and their derivatives, are intended to indicate the orientation of elements shown in the drawings and do not limit the scope of the claims unless expressly stated otherwise in the claims.

[0012] In this specification, the singular forms "a, an" and "the" include the plural form unless otherwise clearly indicated by the context.

[0013] In this specification, the statement that two or more parts or components are “joined” means that the parts are joined or interlocked directly or indirectly, that is, through one or more intermediate parts or components, insofar as a joint exists. As used herein, “directly joined” means that two elements are in direct contact with each other. As used herein, “fixedly joined” or “fixed” means that two components are joined so as to move as a unit while maintaining a fixed orientation relative to each other.

[0014] Figures 1A and 1B show an existing circuit breaker 10. The circuit breaker 10 includes a vacuum housing 12, a drive link 14, an over-toggle mechanism 16, a Thomson coil actuator 18, a shock absorber 20, and a secondary solenoid actuator 22. Separable contacts are housed in the vacuum housing 12. The separable contacts are opened and closed by the operation of the Thomson coil actuator 18 and the secondary solenoid actuator 22, which move a drive shaft coupled to one of the contacts. For example, the drive shaft is moved downward to separate the contacts and upward to push the contacts together. The shock absorber 20 may be an oil-filled shock absorber coupled to the drive shaft. Since rapid and abrupt movements of the drive shaft can damage the circuit breaker 10 over time, the shock absorber 20 is operable to dampen the movement of the drive shaft. The overtoggle mechanism 16 includes multiple springs and is operable to provide a closing contact force and an open contact position latch. The overtoggle mechanism 16 and the shock absorber 20 are bulky components, inefficient, and difficult to expand.

[0015] Figures 2A to 2C illustrate a circuit breaker 100 according to an exemplary embodiment of the disclosed concept. The circuit breaker 100 includes a vacuum housing 102 in which detachable contacts are located. The movable contacts of the detachable contacts are coupled to a drive shaft via a drive link 104. The circuit breaker 100 further includes a Thomson coil actuator 108 that drives the drive shaft to move the detachable contacts closer together or further apart. The circuit breaker 100 also includes a tapered drive shaft section 120 coupled to the lower part of the drive shaft. The tapered drive shaft section 120 has a tapered surface that is narrower at the lower end and wider at the upper end. In one exemplary embodiment, the tapered drive shaft section 120 has a frustoconical shape that is narrower at the lower end than at the upper end. The circuit breaker 100 further includes a washer housing 124 that houses a plurality of washers 122. In one exemplary embodiment of the disclosed concept, the washer is a Belleville washer that is compressed under pressure. The first end of the armature 126 is positioned adjacent to the washer 122 within the washer housing 124. The armature 126 extends from the washer housing 124 to a second end outside the washer housing 124. The roller 128 is coupled to the second end of the armature 126. The washer housing 124, washer 122, armature 126, and roller assembly 128 are positioned such that the roller assembly 128 is in contact with the side surface of the tapered drive shaft section 120. Hereinafter, the washer housing 124, washer 122, armature 126, and roller assembly 128 are collectively referred to as the washer friction assembly. The circuit breaker 100 includes a pair of washer friction assemblies positioned on opposite sides of the tapered drive shaft section 120.

[0016] The washer friction assembly is configured to attenuate the downward movement of the drive shaft by frictional force. More specifically, as shown in FIG. 2B, the separable contacts are pressed against each other, and the drive shaft is in the uppermost position. In this position, the roller device 128 of the washer friction assembly contacts the lower part of the tapered drive shaft section 120. When the drive shaft descends and separates the separable contacts, the tapered drive shaft section 120 moves downward with respect to the washer friction assembly. As a result, as the drive shaft descends, the roller device 128 is pressed against a wider portion of the tapered drive shaft section 120. For example, as shown in FIG. 2C, when the drive shaft moves downward, the roller device 128 contacts a wider portion of the tapered drive shaft section 120 compared to FIG. 2B where the drive shaft is in the uppermost position. When the roller device 128 moves upward to a wider portion of the tapered drive shaft section 120 where the width is wider, the compression of the washer 122 increases, so the friction between the roller device 128 and the tapered drive shaft section 120 increases. This increase in frictional force attenuates the downward movement of the drive shaft. The washer friction assembly provides a compact and highly extensible damping function compared to an oil-filled shock absorber.

[0017] It will be understood that the washer and roller device are merely exemplary embodiments of the disclosed concept. The roller device can be replaced with other types of friction devices configured to interact with the tapered surface of the tapered drive shaft section 120 without departing from the scope of the disclosed concept. For example, without limitation, a bushing or brake pad may be used instead of the roller device without departing from the scope of the disclosed concept. Further, instead of the washer, other biasing devices such as, but not limited to, a spring can be used to bias the armature device and the roller device toward the tapered surface of the tapered drive shaft section 120.

[0018] Figures 3A to 3C show another embodiment of the circuit breaker 200. The circuit breaker 200 includes a vacuum housing 202, a detachable contact, a drive shaft, a drive link 104, a Thomson coil 108, and a pair of washer friction assemblies (including a washer 122, a washer housing 124, an armature 126, and a roller device 128), similar to the circuit breaker 100 in Figures 2A to 2C (similar to the vacuum housing 102, a detachable contact, a drive shaft, a drive link 204, a Thomson coil 208, and a pair of washer friction assemblies (including a washer 222, a washer housing 224, an armature 226, and a roller device 228). For the sake of brevity of disclosure, repeated descriptions of these components are omitted.

[0019] The circuit breaker 200 includes a tapered drive shaft section 220 having a frustoconical shape. However, unlike the tapered drive shaft section 120 shown in FIGS. 2A-2C, the tapered drive shaft section 220 further includes a pair of arcuate cutouts 221 on its upper surface. The shape of the arcuate cutouts 221 corresponds to the shape of the lower surface of the roller device 228. The arcuate cutouts 221 are operable to latch the circuit breaker 200 in the open position. More specifically, the washer friction device and the tapered drive shaft 220 provide a damping function as the drive shaft moves downward and the roller device 228 contacts a wider portion of the tapered drive shaft section 220. For example, in FIG. 3A, the drive shaft is located at the uppermost position and the roller device 228 contacts a narrower portion of the tapered drive shaft section 220. In FIG. 3B, the drive shaft moves downward and the roller device 228 contacts a wider portion of the tapered drive shaft section 220, thus increasing the frictional force against the tapered drive shaft section 220 and suppressing the downward movement of the drive shaft. As the drive shaft continues to descend, the roller device 228 reaches the upper edge of the tapered drive shaft section 220. When the roller device 228 passes the upper edge of the tapered drive shaft section 220, the pressure of the washer 222 pushes the roller device 228 towards the center of the tapered drive shaft section 220. As shown in FIG. 3C, the roller device 228 comes to seat in the arcuate cutouts 221. While the roller device 228 is seated in the arcuate cutouts 221, the roller device 228 prevents further upward movement of the drive shaft. That is, the circuit breaker 200 is in the latched open state and cannot close the separable contacts. Thus, the washer friction assembly and the tapered drive shaft section 220 provide a damping function that is compact and scalable compared to an oil-filled shock absorber, and a latch function that is compact, scalable, and highly reliable compared to a spring-type over-trip mechanism.

[0020] Figures 4A to 4C show another exemplary embodiment of the circuit breaker 300. The circuit breaker 300 includes, similar to the circuit breaker 100 in Figures 2A to 2C (similar to the vacuum housing 102, detachable contacts, drive shaft, drive link 104, Thomson coil 108, tapered drive shaft section 120, and a pair of washer friction assemblies (including washers 122, washer housing 124, armature 126, and roller device 128)), a vacuum housing 302, detachable contacts, drive shaft, drive link 304, Thomson coil 308, tapered drive shaft 320, and a pair of washer friction assemblies (including washers (not shown), washer housing 324, armature 326, and roller device 328). For the sake of brevity of disclosure, repeated descriptions of these components are omitted.

[0021] The circuit breaker 300 further includes a pair of latch assemblies, each latch assembly including a latch arm 340 and a spring-loaded latch 342. The pair of latch assemblies are located opposite the tapered drive shaft section 320 in a plane perpendicular to the plane in which the washer friction assembly is located. The latch arm 340 is an angled member configured to rotate around a pivot point near the spring-loaded latch 342. The upper part of the latch arm 340 extends across the uppermost side of the tapered drive shaft section 320. The latch arm 340 includes an extension that extends from the pivot point toward the spring-loaded latch 342.

[0022] The spring-loaded latch 342 includes a spring and a latch member. The spring is configured to bias the latch member toward the latch arm 340. The latch member includes a flat upper side and a curved lower side. The latch member is structured to interact with the extension of the latch arm 340 to latch the circuit breaker 300 into an open position. More specifically, Figure 4B shows the circuit breaker 300 in the closed position, with the detachable contacts closed and the drive shaft in its uppermost position. In this position, the tip of the extension of the latch arm 340 is at or below the upper edge of the latch member. Figure 4C shows the circuit breaker 300 in the open position, with the drive shaft moving downward and the detachable contacts open. As the drive shaft moves downward, the upper part of the latch arm 340 rotates toward the drive shaft. This rotation moves the extension of the latch arm 340 upward above the uppermost edge of the latch member. When the tip of the extension of the latch arm 340 moves above the uppermost edge of the latch member, the spring pushes the latch member toward the extension of the latch arm 340, causing the latch member to slide below the extension of the latch arm. In this position, shown in Figure 4C, the latch arm 340 prevents the drive shaft from moving upward to close the detachable contacts. More specifically, in this position, the upper end of the latch arm 340 abuts against the upper end of the tapered drive shaft section 320, and the lower side of the extension of the latch arm 340 abuts against the upper side of the latch member. Thus, the upper side of the latch arm 340 cannot move upward because the extension of the latch arm 340 abuts against the latch member, preventing rotation in that direction. Therefore, the drive shaft cannot move upward to close the detachable contacts, and the circuit breaker 300 is latched in the open position. The circuit breaker 300 provides damping function via the washer friction assembly and the tapered drive shaft section 320. This damping function is more compact and expandable compared to oil-filled shock absorbers, and the latch arm 340 and spring-loaded latch 342 provide a more compact, expandable, and reliable latching function compared to spring-loaded overtoggle mechanisms.

[0023] Figures 5A and 5B show another exemplary embodiment of the circuit breaker 400. The circuit breaker 400 includes a vacuum housing 402, a detachable contact, a drive shaft, a drive link 104, a Thomson coil 108, and a pair of washer friction assemblies (including a washer (not shown), a washer housing 424, an armature 426, and a roller assembly 428), similar to the circuit breaker 100 in Figures 2A and 2C (similar to the vacuum housing 102, detachable contacts, a drive shaft, a drive link 404, a Thomson coil 408, and a pair of washer friction assemblies (including a washer (not shown), a washer housing 424, an armature 426, and a roller assembly 428). For the sake of brevity of disclosure, repeated descriptions of these components are omitted.

[0024] The circuit breaker 400 includes a tapered drive shaft section 420, which includes two opposing tapered surfaces and two opposing grooved surfaces. Similar to the washer friction assembly and tapered drive shaft 120 of the circuit breaker 100 in Figures 1A to 1C, the tapered surfaces of the tapered drive shaft section 420 correspond to the washer friction assembly and work in conjunction with the washer friction assembly to dampen the downward movement of the drive shaft.

[0025] The circuit breaker 400 further includes a pair of ratchet latch assemblies corresponding to the grooved surface of the tapered drive shaft section 420. Each ratchet latch assembly includes a spring-loaded latch 442 and a gear 440. The spring-loaded latch 442, the gear 440, and the grooved surface of the tapered drive shaft section 420 are operable as a ratchet mechanism. That is, the spring-loaded latch 442 and the gear 440 are configured such that the spring-loaded latch 442 allows the gear 440 to rotate in one direction, but prevents the gear 440 from rotating in the opposite direction like a ratchet. The gear 440 and the grooved surface of the tapered drive shaft section 420 are configured such that the teeth of the gear 440 and the teeth of the grooved surface of the tapered drive shaft section 420 operate similarly, allowing the grooved surface of the tapered drive shaft section 420 to move upward, but preventing downward movement due to the interaction between the teeth of the gear 440 and the teeth of the grooved surface of the tapered drive shaft section 420. Naturally, reversing the orientation of the teeth can prevent movement in the reverse direction. That is, the ratchet latch mechanism can be used to latch the circuit breaker 400 into an open or closed position without departing from the scope of the disclosed concept. The circuit breaker 400 provides damping function via a washer friction assembly and a tapered drive shaft section 420, which is more compact and expandable compared to an oil-filled shock absorber. Furthermore, the gear 440 and spring-loaded latch 442 provide a more compact, expandable, and reliable latching function compared to a spring-loaded overtoggle mechanism.

[0026] While specific embodiments of the present invention have been described in detail, various modifications and substitutions to these details will be understandable to those skilled in the art in light of the overall teachings of this disclosure. Accordingly, the specific configurations disclosed are for illustrative purposes only and do not limit the scope of the concepts disclosed, and the entire scope of the appended claims and all their equivalents should be considered.

Claims

1. A circuit breaker, and said circuit breaker is A detachable contact, A drive shaft connected to the detachable contact and configured to move the detachable contact to open and close, A tapered drive shaft section having a tapered surface is coupled to the drive shaft, Friction assembly and, The friction assembly is A friction device configured to interact with the tapered surface of a tapered drive shaft, an armature connected to the friction device, The friction device and the biasing member configured to bias the armature toward the tapered drive shaft section are included. Circuit breaker.

2. The circuit breaker according to claim 1, wherein the friction device is a roller device.

3. The circuit breaker according to claim 1, wherein the biasing member is a plurality of washers.

4. The circuit breaker according to claim 3, wherein the plurality of washers are a plurality of Belleville washers.

5. The circuit breaker according to claim 1, wherein the tapered drive shaft section has a frustoconical shape.

6. The circuit breaker according to claim 1, wherein the upper surface of the tapered drive shaft section includes an arc-shaped notch corresponding to the shape of the friction device, and when the tapered drive shaft section moves downward beyond a predetermined point, the friction device extends into the arc-shaped notch and seats.

7. The circuit breaker according to claim 6, wherein when the friction device is seated in the arc-shaped notch, the detachable contact is in the open position, and the interaction between the friction device and the arc-shaped notch prevents the detachable contact from moving to the closed position.

8. The circuit breaker according to claim 1, wherein the friction assembly comprises a first friction assembly and a second friction assembly, the first friction assembly and the second friction assembly being located on the opposite side of the tapered drive shaft section.

9. A circuit breaker, and said circuit breaker is A detachable contact, A drive shaft connected to the detachable contact and configured to move the detachable contact to open and close, A tapered drive shaft section having a tapered surface is coupled to the drive shaft, The latch arm assembly includes, The latch arm assembly is A latch arm configured to rotate around a pivot point, wherein the upper end of the latch arm extends beyond the upper end of the tapered drive shaft section, A spring-loaded latch, comprising a spring-loaded latch configured to extend in such a way as to prevent the latch from rotating beyond a predetermined point in one direction, Circuit breaker.

10. Further including a friction assembly, The friction assembly is A friction device configured to interact with the tapered surface of the tapered drive shaft, An armature connected to the friction device, The circuit breaker according to claim 9, comprising the friction device and a biasing member configured to bias the armature toward the tapered drive shaft section.

11. The circuit breaker according to claim 10, wherein the biasing member is a plurality of washers.

12. The circuit breaker according to claim 9, wherein the latch arm includes an extension positioned near the pivot point, the extension being configured to interact with the spring-loaded latch.

13. A circuit breaker, and said circuit breaker is A detachable contact, A drive shaft is coupled to the detachable contact and configured to move the detachable contact to open and close, A tapered drive shaft section having a tapered surface and grooved side surface is coupled to the drive shaft, Ratchet assembly and, The ratchet assembly is, A gear configured to interact with the groove side surface of the tapered drive shaft section, thereby allowing movement of the tapered drive shaft in a first direction and preventing movement in the opposite second direction, A spring-loaded latch configured to interact with the gear to allow the gear to rotate in a first direction and to prevent the gear from rotating in a second, opposite direction, Circuit breaker.

14. Further including a friction assembly, The friction assembly is A friction device configured to interact with the tapered surface of the tapered drive shaft, An armature connected to the friction device, The circuit breaker according to claim 13, further comprising the friction device and a biasing member configured to bias the armature toward the tapered drive shaft section.

15. The circuit breaker according to claim 14, wherein the multiple washers are multiple Belleville washers.

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