Patent Application
20190214211
The field of the disclosure relates generally to mechanical devices for circuit breakers, and, more specifically, to a collapsible link device for quick termination of an electrical connection.
Circuit breakers include electrical contacts that complete a circuit with an electrical system. However, the flow of current to connected loads is interruptible by separating the electrical contacts during an interrupt event, such as in a short circuit event. Damage may occur to the circuit breaker and/or to downstream electrical equipment if the flow of current is not interrupted quickly enough. As such, faster separation of electrical contacts may protect the circuit breaker and may protect downstream electrical equipment.
In one aspect, a collapsible link device for a circuit breaker is provided. The collapsible link device includes a side frame, a carrier, a main contact arm, a plurality of collapsible links, and a release mechanism. The carrier is pivotably coupled to the side frame. The main contact arm is pivotably coupled to the carrier and includes a first end including a first electrical contact. The plurality of collapsible links are pivotably coupled to the side frame and the carrier. The release mechanism is pivotably coupled to at least one of the collapsible links and the carrier. The plurality of collapsible links are movable between an uncollapsed position in which the first electrical contact contacts a second electrical contact and a collapsed position that results from the first electrical contact separating from the second electrical contact.
In another aspect, a method of manufacturing a collapsible link device for a circuit breaker is provided. The method includes pivotably coupling a carrier and a main contact arm to a side frame. A first end of the main contact arm including a first electrical contact. The method also includes pivotably coupling a plurality of collapsible links to the side frame and the carrier. The method further includes coupling a release mechanism to the carrier. The plurality of collapsible links are movable between an uncollapsed position in which the first electrical contact contacts a second electrical contact and a collapsed position that results from the first electrical contact separating from the second electrical contact.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of this disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, and such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
The collapsible link devices and associated systems and methods described herein are suited to quickly disconnect electrical contacts in a circuit breaker during an interrupt event, such as a short circuit event. Quickly disconnecting the electrical contact prevents damage to the circuit breaker and to downstream electrical equipment. The collapsible link devices of the present disclosure include a main contact arm, a first electrical contact positioned on a first end of the main contact arm and electrically coupled to a second electrical contact of an electrical system, a release mechanism, a plurality of collapsible links, and a plurality of springs. During normal operation (i.e., in the absence of an interrupt event), the collapsible links, the main contact arm, the springs, and the release mechanism are configured to maintain contact between the first and second electrical contacts. During an interrupt event, such as a short circuit event, electromagnetic forces caused by the interrupt event push the first electrical contact away from the second electrical contact, causing the main contact arm to pivot about a first pivot point. Rotation of the main contact arm actuates the release mechanism which, in turn, releases the collapsible links and pivots the first electrical contact away from the second electrical contact. The springs are coupled to the collapsible links and accelerate the pivot of the main contact arm. In a first embodiment, the release mechanism includes a link trip latch that releases the collapsible links by rotating when the main contact arm rotates. In a second embodiment, the release mechanism includes a link pin that releases the collapsible links by sliding out of a slot.
In the exemplary embodiment, collapsible links 110 include three links: a lower link 124, a cam link 126, and an upper link 128. In alternative embodiments, collapsible links 110 include any number of links that enable collapsible link device 100 to operate as described herein. Lower link 124 is pivotably coupled to carrier 104 by a fifth pivot pin 130 (shown in
In the exemplary embodiment, main contact arm 106 includes a first electrical contact 138 on a first end 140 of main contact arm 106. The circuit breaker include a second electrical contact 142. As shown in
In the exemplary embodiment, collapsible link device 100 includes a release mechanism 144. In the illustrated embodiment, release mechanism 144 includes a trip latch link 146. Trip latch link 146 includes a first end 148 and a second end 150, and is pivotably coupled to lower link 124 by a ninth pivot pin 152. First end 148 and second end 150 of trip latch link 146 are positioned on opposite sides of ninth pivot pin 152. In the exemplary embodiment, second end 150 of trip latch link 146 is positioned at an angle relative to first end 148 of trip latch link 146. Trip latch link 146 is configured to maintain electrical contact between first electrical contact 138 and second electrical contact 142 by maintaining carrier 104, main contact arm 106, and collapsible links 110 in a first position or an uncollapsed position (i.e., the configuration shown in
In the exemplary embodiment, collapsible link device 100 includes three biasing members or springs: a main arm spring 154, a flat spring 156, and an interrupt spring 158. Main arm spring 154 is coupled between first end 140 of main contact arm 106 and carrier 104. Main arm spring 154 imparts a biasing force against first end 140 of main contact arm 106 in a first direction 160, imparting to main contact arm 106 a moment, or pivoting force or movement, about first pivot pin 116 which maintains contact between first electrical contact 138 and second electrical contact 142.
Flat spring 156 is coupled between carrier 104 and second end 150 of trip latch link 146. Flat spring 156 imparts a biasing force against second end 150 of trip latch link 146 in a second direction 162, imparting to trip latch link 146 a moment, or pivoting force or movement, about ninth pivot pin 152 which maintains contact between first end 148 of trip latch link 146 and flat portion 153 of carrier 104.
Interrupt spring 158 is coupled between handle 108 and second pivot pin 118. Interrupt spring 158 imparts a biasing force that pulls second pivot pin 118 and upper link 128 in a third direction 164 towards handle 108. Pulling second pivot pin 118 and upper link 128 in third direction 164, absent moving forces, causes collapsible links 110 to collapse, rotating carrier 104, main contact arm 106, and first electrical contact 138 away from second electrical contact 142. In the exemplary embodiment, trip latch link 146 prevents collapsible links 110 from collapsing and maintaining contact between first electrical contact 138 and second electrical contact 142.
During an interrupt event, such as a short circuit of the electrical system, electromagnetic forces repel first electrical contact 138 away from second electrical contact 142.
As main contact arm 106 rotates about first pivot pin 116, a contact portion 168 of main contact arm 106 makes contact with and rotates second end 150 of trip latch link 146 about ninth pivot pin 152 in a fifth direction 170. Flat spring 156 includes a predetermined spring constant and imparts a predetermined resistive force against the rotation of second end 150 of trip latch link 146 in fifth direction 170. As such, flat spring 156 is operable to prevent rotation of second end 150 of trip latch link 146 until the rotational force from contact portion 168 of main contact arm 106 exceeds the predetermined resistive force of flat spring 156. Rotating trip latch link 146 about ninth pivot pin 152 rotates first end 148 of trip latch link 146 away from flat portion 153 of carrier 104 in a sixth direction 172 opposite fifth direction 170, causing lower link 124 to rotate about fifth pivot pin 130 in a seventh direction 174 and collapsing collapsible links 110.
After an interrupt event has been initiated, collapsible links 110 rapidly collapse and rotate first electrical contact 138 away from second electrical contact 142.
To prevent damage to the circuit breaker and to downstream electrical equipment within the electrical system, interrupt spring 158 pulls collapsible links 110 toward handle 108, thereby rotating carrier 104 and main contact arm 106 about first pivot pin 116 faster.
Rotation of upper portion 184 of upper link 128 to pivot about second pivot pin 118 in tenth direction 186 causes cradle 112 to pivot about third pivot pin 120 in an eleventh direction 188. As shown in
After the interrupt event is over, handle 108 may be manually rotated (i.e., by a human operator) in a thirteenth direction 192 opposite eleventh direction 188 to latch cradle 112 back into latch 114. Rotation of handle 108 in thirteenth direction 192 also rotates collapsible links 110, carrier 104, and main contact arm 106 back into the first position (i.e., the configuration shown in
A circuit breaker may include one collapsible link device 100 or may include a plurality of collapsible link devices 100. When a circuit breaker includes a plurality of collapsible link devices 100, the circuit breaker may include a bar 194 (shown in
During an interrupt event, such as a short circuit of the electrical system, electromagnetic forces repel first electrical contact 138 away from second electrical contact 142.
As main contact arm 106 rotates about first pivot pin 116, a contact portion 268 of main contact arm 106 makes contact with and slides link lock pin 248 out of short portion 255 of carrier groove 250 and main contact arm groove 252. As link lock pin 248 slides link lock pin 248 out of short portion 255 of carrier groove 250 and main contact arm groove 252, lower link 124 is allowed to rotate about a fifth pivot pin 130 in a seventh direction 174, collapsing collapsible links 110. Once collapsible links 110 have collapsed as described above, link lock pin 248 slides into long portion 253 of carrier groove 250 and main contact arm groove 252, allowing collapsible links 110 to collapse further and allowing carrier 104 and main contact arm 106 to rotate first electrical contact 138 away from second electrical contact 142.
The above-described embodiments of collapsible link devices and associated systems and methods are suited to quickly disconnect an electrical contact in a circuit breaker during an interrupt event, such as a short circuit event. The above-described embodiments include a plurality of collapsible links and a plurality of springs that speed up the process of disconnecting electrical contacts in a circuit breaker. Quickly disconnecting the electrical contact prevents damage to the circuit breaker and to downstream electrical equipment. As such, the above-described embodiments are suited to preventing damage to the circuit breaker and to downstream electrical equipment.
Exemplary embodiments of the above-described collapsible link devices and associated systems and methods of use thereof are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods, systems, and apparatus may also be used in combination with other systems requiring collapsible link devices, and the associated methods are not limited to practice with only the systems and methods as described herein. Rather, the exemplary embodiments can be implemented and utilized in connection with many other applications, equipment, and systems that may benefit from using the above-described embodiments of the above-described collapsible link devices and associated systems and methods of use thereof to improve the safety and reliability of electrical systems.
Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
