1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly to electrical switching apparatus, such as circuit breakers. The disclosed concept also relates to shaft assemblies.
2. Background Information
Electrical switching apparatus, such as circuit breakers, as well as transfer switches, network protectors and the like, are often equipped with accessories such as, for example and without limitation, auxiliary switches, shunt trip devices, under voltage release devices, and bell alarms. Such devices can be employed in a variety of ways to provide signals indicating certain conditions within the apparatus and/or to initiate a change in status of the apparatus such as, for example, to trip open the separable contacts of the apparatus in response to an electrical fault condition (e.g., without limitation, current overload; short circuit; abnormal voltage).
Some of these accessories include an actuator, such as a stem or plunger, that is movable from a retracted position to an extended position in which it is structured to engage and actuate (e.g., pivot) a corresponding shaft assembly (e.g., without limitation, trip bar; D-shaft) associated with the circuit breaker operating mechanism. Accordingly, it will be appreciated that such shaft assemblies can be employed in cooperation with a wide variety of different accessories to facilitate circuit breaker operations.
Typically, the trip bar or D-shaft is pivotally supported by bearings, with an end of the shaft extending through and beyond one of the bearings such that it is cantilevered with respect thereto. The cantilevered end of the shaft includes a number of protrusions (e.g., without limitation, paddles) extending radially outwardly from the shaft. Each actuator (e.g., without limitation, stem; plunger) of the aforementioned accessories engages and moves a corresponding one of the paddles in order to pivot the shaft and initiate the desired circuit breaker operation. Among other disadvantages, such shaft assemblies are reliant upon strict, difficult to achieve tolerances with respect to shaft assembly components, and relatively minimal misalignment among the assembly components can cause the shaft assembly, and thus the circuit breaker, to not function properly.
There is, therefore, room for improvement in electrical switching apparatus, such as circuit breakers, and in shaft assemblies therefor.
These needs and others are met by embodiments of the disclosed concept, which are directed to a shaft assembly for an electrical switching apparatus, such as a circuit breaker. Among other benefits, the shaft assembly employs a paddle assembly that addresses and overcomes tolerance and misalignment problems associated with known shaft assemblies.
As one aspect of the disclosed concept, a shaft assembly is provided for an electrical switching apparatus. The electrical switching apparatus includes a housing and a pivotal shaft. The shaft assembly comprises: a paddle assembly comprising an elongated body including a first end and a second end disposed opposite and distal from the first end, and a number of paddles extending radially outwardly from the elongated body; and a support bracket structured to be coupled to the housing of the electrical switching apparatus. The first end of the elongated body is structured to be coupled to and supported by the pivotal shaft, and the second end of the elongated body is coupled to and supported by the support bracket.
The support bracket may be an accessory mounting bracket. The accessory mounting bracket may further comprise a first end, a second end disposed opposite and distal from the first end of the accessory mounting bracket, plurality of fasteners, and a removable accessory tray. A first number of the fasteners may be structured to fasten the first end of the accessory mounting bracket to the housing of the electrical switching apparatus, and a second number of the fasteners may be structured to fasten the second end of the accessory mounting bracket to the housing of the electrical switching apparatus.
As another aspect of the disclosed concept, an electrical switching apparatus comprises: a housing; separable contacts enclosed by the housing; an operating mechanism structured to open and close the separable contacts, the operating mechanism including a pivotal shaft; and a shaft assembly comprising: a paddle assembly comprising an elongated body including a first end and a second end disposed opposite and distal from the first end, and a number of paddles extending radially outwardly from the elongated body, and a support bracket coupled to the housing. The first end of the elongated body is coupled to and supported by the pivotal shaft, and the second end of the elongated body is coupled to and supported by the support bracket.
The paddle assembly may further comprise a separate molded member movably coupled to the elongated body wherein, responsive to movement of the separate molded member, the elongated body moves with the separate molded member, and wherein the elongated body is pivotable independently with respect to the separate molded member. The separate molded member may be a pivotal molded ring, and the first end of the elongated body may extend through the pivotal molded ring. The pivotal molded ring may include an accessory paddle and a contact portion, and the paddle assembly may further comprise a molded projection projecting radially outwardly from the elongated body wherein, when the pivotal molded ring pivots, the contact portion engages the molded projection, thereby pivoting the elongated body.
The electrical switching apparatus may be a circuit breaker, wherein the circuit breaker further comprises a trip actuator and a number of accessories. Each of the trip actuator and the number of accessories may include an actuator. The accessory paddle of the molded ring may cooperate with the actuator of the trip actuator, and each of the paddles of the paddle assembly may cooperate with the actuator of a corresponding one of the number of accessories.
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, upwards, downwards 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 term “fastener” refers to any suitable connecting or tightening mechanism expressly including, but not limited to, rivets, screws, bolts and the combinations of bolts and nuts (e.g., without limitation, lock nuts) and bolts, washers and nuts.
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).
The example shaft assembly 100 includes a paddle assembly 102 having an elongated body 104 with first and second opposing ends 106,108. A number of paddles 110,112 (best shown in
In other words, as will be described in greater detail hereinbelow, the shaft assembly 100 essentially comprises a separate sub-assembly that attaches to and forms an extension of the pivotal shaft 10 (e.g., without limitation, D-shaft) of the circuit breaker 2. The elongated body 104 of the paddle assembly 102 of the shaft assembly 100 is preferably movable with, but not independently with respect to, the pivotal shaft 10, whereas the elongated body 104 of the paddle assembly 102 does pivot with respect to the support bracket 114.
Another unique feature of the shaft assembly 100 can be further appreciated with reference to
The manner in which the shaft assembly 100 is supported will now be described in greater detail. Specifically, as shown in
A still further unique aspect of the disclosed shaft assembly 100 is that the support bracket is preferably an integral accessory mounting bracket 114, as shown in the example of
The example circuit breaker 2 includes first and second side plates 18,20 disposed opposite and spaced apart from one another, as shown in
More specifically, the example accessory mounting bracket 114 further includes first and second opposing ends 164,166 and a plurality of fasteners 168,170 (two fasteners 168,170 are shown in the example of
In view of the foregoing, it will be appreciated that the accessory mounting bracket 114 functions not only to support the shaft assembly 100, but also removably receives the aforementioned removable accessory tray 250 and a number of accessories such as, for example and without limitation, the first and second accessories 300,400, which are mounted thereto as shown in the example of
Accordingly, the disclosed shaft assembly provides an efficient and effective mechanism for transferring movement from, for example and without limitation, a primary trip actuator 200 and/or any known or suitable number, type and configuration of circuit breaker accessories (e.g., 300,400) to facilitate various circuit breaker operations, as desired. Among other benefits, the shaft assembly 100 is well supported and is configured so as to overcome the misalignment and tolerance problems known to be associated with prior art shaft assembly designs (not shown).
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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Number | Date | Country | |
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20110073451 A1 | Mar 2011 | US |