1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to charging assemblies for electrical switching apparatus. The disclosed concept also relates to electrical switching apparatus, such as circuit breakers.
2. Background Information
Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as, for example, current overloads, short circuits, abnormal voltage and other fault conditions. Typically, circuit breakers include an operating mechanism, which opens electrical contact assemblies to interrupt the flow of current through the conductors of an electrical system in response to such fault conditions as detected, for example, by a trip unit. The electrical contact assemblies include stationary electrical contacts and corresponding movable electrical contacts that are separable from the stationary electrical contacts.
Among other components, the operating mechanisms of some low and medium voltage circuit breakers, for example, typically include a poleshaft, a trip actuator assembly, a closing assembly and an opening assembly. The trip actuator assembly responds to the trip unit and actuates the operating mechanism. The closing assembly and the opening assembly may have some common elements, which are structured to move the movable electrical contacts between a first, open position, wherein the movable and stationary electrical contacts are separated, and a second, closed position, wherein the movable and stationary electrical contacts are electrically connected. Specifically, the movable electrical contacts are coupled to the poleshaft. Elements of both the closing assembly and the opening assembly, which are also pivotably coupled to the poleshaft, pivot the poleshaft in order to effectuate the closing and opening of the electrical contacts. A charging assembly, which includes a number of stored energy mechanisms, is often employed to facilitate operation of the closing assembly.
As shown, for example, in
There is, therefore, room for improvement in charging assemblies, and in electrical switching apparatus, such as circuit breakers, which employ charging assemblies.
These needs and others are met by embodiments of the disclosed concept, which are directed to a charging assembly for an electrical switching apparatus, such as a circuit breaker. Among other benefits, the charging assembly includes a catchment that cooperates with the closing spring casting to control movement (e.g., resist over rotation) of the cam shaft.
As one aspect of the disclosed concept, a charging assembly is provided for an electrical switching apparatus. The electrical switching apparatus includes a housing, separable contacts enclosed by the housing, and an operating mechanism for opening and closing the separable contacts. The charging assembly comprises: a stored energy mechanism movable between a charged position and a discharged position; a cast member coupled to the stored energy mechanism and being movable therewith, the cast member including a projection; a cam shaft structured to be pivotably coupled to the housing, the cam shaft including a number of cams; and a catchment structured to be pivotably coupled to the housing, the catchment comprising an impact surface and a protrusion. The impact surface of the catchment cooperates with a corresponding one of the cams to resist over rotation of the cam shaft. The protrusion of the catchment cooperates with the projection of the cast member to maintain the desired relationship between the catchment and the corresponding one of the cams.
The catchment may further comprise a pivot member, a first portion, a second portion, and a third portion. The pivot member may be structured to pivotably couple the first portion to the housing of the electrical switching apparatus, the second portion may cooperate with the corresponding one of the cams, and the third portion may cooperate with the projection of the cast member. The impact surface may be disposed on the second portion of the catchment, and the protrusion may be disposed on the third portion of the catchment, wherein the protrusion extends outwardly from the catchment proximate the impact surface. The catchment may be a single piece member, wherein the protrusion is a generally rectangular-shaped portion extending outwardly from the third portion of the single piece member. The protrusion may have an outer edge wherein, when the impact surface of the catchment engages the corresponding one of the cams, the outer edge of the protrusion cooperates with the projection of the cast member.
The cast member may be a single piece spring casting, and the projection may project laterally outwardly from the single piece spring casting and include a retaining edge. The retaining edge of the single piece spring casting may retain the outward edge of the catchment, thereby preventing the impact surface of the catchment from releasing the corresponding one of the cams.
As another aspect of the disclosed concept, an electrical switching apparatus employing the aforementioned charging assembly is disclosed.
A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
Directional phrases used herein, such as, for example, clockwise, counterclockwise, left, right, upward, downward and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.
As employed herein, the statement that two or more parts are “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts.
As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).
As best shown in
Accordingly, it will be appreciated that, among other benefits, the projection 220 and protrusion 226 features of the disclosed concept, function to augment operation of the catchment 214 by interlocking the catchment 214 with the spring casting 218 in a manner which prevents glancing collision, for example, that could otherwise occur between the catchment surface 222 of cam 212 and impact surface 224 of catchment 214. In this manner, the disclosed charging assembly 200 provides a back-up mechanism for resisting over rotation of the cam shaft 208 and damage associated therewith. For example and without limitation, issues such as breaker vibration can cause prior art catchments (see, for example and without limitation, catchment 14 of
More specifically, the catchment 214 in the non-limiting example shown and described herein, preferably includes a pivot member 228, a first portion 230, a second portion 232, and a third portion 234. The pivot member 228 pivotably couples the first portion 230 to the circuit breaker housing 104 and, in particular, to a side plate 110 (partially shown in hidden line drawing in
As best shown in
The cast member 218 is preferably a single piece spring casting, wherein the projection 220 projects laterally outwardly from the single piece spring casting 218 and includes a retaining edge 238. The retaining edge 238, therefore, retains the outward edge 236 of the catchment 214, as shown in
As previously discussed hereinabove, the example stored energy mechanism is a closing spring 204. The closing spring 204 has opposing first and second ends 240,242 (FIGS. 2 and 4-7). The spring casting 218 is disposed on the second end 242 of the closing spring 204 and moves therewith in the direction of arrow 300, as shown in
Accordingly, it will be appreciated that the disclosed charging assembly 200 includes unique catchment 214 and spring casting 218 features (e.g., without limitation, projection 220 of spring casting 218, and protrusion 226 of catchment 214), which interact to prevent the cam shaft 208 from slipping past (e.g., over rotating) the catchment 214 until the spring casting 218 is sufficiently close to the completely closed position. Therefore, the disclosed concept functions to augment catchment operation by interlocking the catchment 214 with the spring casting 218 in a manner that prevents glancing collisions and/or damage to the cam 212 and catchment 214 that can cause cam shaft over rotation.
While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.
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Entry |
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International Search Report and Written Opinion for International Application No. PCT/US2012/064594, issued Feb. 14, 2013. |
Number | Date | Country | |
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20130134020 A1 | May 2013 | US |