1. Field of the Invention
The present invention relates generally to electrical switching apparatus and, more particularly, to a locking assembly for locking the tripping component of a circuit breaker.
2. Background Information
For safety, electrical switching apparatus, such as circuit breakers, may be de-energized before performing an operation (e.g., maintenance; test; reconfiguration) thereon. Damage to electrical equipment, severe personal injury and even death can result from contact with electrical equipment when it is energized. It is, therefore, often desirable to maintain the breaker in the open and discharged condition during such operations. One way of accomplishing this is to lock the tripping component of the circuit breaker in the tripped position, thereby preventing the separable contacts of the breaker from closing.
Known prior art circuit breakers employ a variety of locking assemblies in order to prevent the circuit breaker from closing when maintenance is being performed. One such device involves an interlock assembly which employs a commercially available lock, such as a key lock (e.g., without limitation, key locks respectively sold under the trademarks CASTELL®, RONIS® and KIRK®), which is coupled to the tripping component (e.g., trip bar) of the circuit breaker in order that the configuration of the circuit breaker can be controlled (e.g., locked) from outside the breaker.
Each type of lock employs a different key 18 (
It is, therefore, desirable to provide an economical locking assembly which may be employed in a variety of electrical switchgear applications.
There is, therefore, room for improvement in locking assemblies for the trip components of electrical switching apparatus and in electrical switching apparatus employing locking assemblies.
These needs and others are satisfied by the present invention, which is directed to a locking assembly for the trip component of an electrical switching apparatus, such as the trip bar of a circuit breaker. The locking assembly includes a flexible linkage which is economical to make and which is interchangeable for use with a variety of electrical switching apparatus employing any known or suitable commercially available lock.
As one aspect of the invention, a locking assembly is for an electrical switching apparatus including separable contacts and an operating mechanism for opening and closing the separable contacts. The operating mechanism includes a trip component operable between first and second positions corresponding to the separable contacts being tripped open and closable, respectively, and a pivotal trip lever coupled to the trip component in order to move therewith. The locking assembly comprises: a locking mechanism including a pivotal element; a mounting plate structured to receive the locking mechanism and secure it to the electrical switching apparatus; an extension member coupled to the pivotal element of the locking mechanism and adapted to move therewith; and a flexible linkage structured to interconnect the pivotal trip lever and the extension member.
As another aspect of the invention, the pivotal trip lever may be included as a component of the locking assembly which is structured to be subsequently coupled to the trip component of the electrical switching apparatus in order to move therewith.
The locking mechanism may have locked and unlocked positions corresponding to the first and second positions, respectively, of the trip component wherein the extension member is adapted to move with the pivotal element of the locking mechanism thereby moving the flexible linkage which is structured to pivot and lock the pivotal trip lever and the trip component to which the pivotal trip lever is structured to be coupled, in the first position when the pivotal element of the locking mechanism is disposed in the locked position. The trip component and the pivotal trip lever may be spring-loaded, in order that it is biased, for example, toward the second position. The extension member may be adapted to move with the pivotal element of the locking mechanism thereby moving the flexible linkage which is structured to permit the pivotal trip lever and the trip component to which it is structured to be coupled, to unlock and pivot toward the second position when the pivotal element of the locking mechanism is pivoted from the locked position to the unlocked position.
The flexible linkage may be a cable including first and second ends which are coupled to the pivotal trip lever and the extension member, respectively, by fasteners. The pivotal trip lever and the extension member may include first and second openings, respectively, wherein the first and second ends of the cable include first and second eyelets, respectively, and the first end of the cable is secured to the pivotal trip lever by one of the fasteners inserted through the first eyelet into the first opening of the pivotal trip lever and the second end of the cable is secured to the extension member by another one of the fasteners inserted through the second eyelet into the second opening of the extension member.
As another aspect of the invention, an electrical switching apparatus comprises: separable contacts; an operating mechanism for opening and closing the separable contacts, the operating mechanism including a trip component operable between first and second positions corresponding to the separable contacts being tripped open and closable, respectively, a pivotal trip lever coupled to the trip component in order to move therewith; and a locking assembly comprising: a locking mechanism including a pivotal element, a mounting plate for receiving the locking mechanism and securing it to the electrical switching apparatus, an extension member coupled to the pivotal element of the locking mechanism in order to move therewith, and a flexible linkage interconnecting the pivotal trip lever and the extension member.
The electrical switching apparatus may be a circuit breaker wherein the trip component of the circuit breaker is a trip bar. The locking mechanism may be a commercially available key lock, wherein the pivotal element of the key lock receives a key and pivots when the key is inserted and rotated.
A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:
For purposes of illustration, the invention will be described as applied to the trip component of a circuit breaker in order to prevent closing of the breaker separable contacts during the performing of an operation (e.g., maintenance; test; reconfiguration) thereon, although it will become apparent that it could also be applied to other types of electrical switching apparatus (e.g., without limitation, circuit switching devices and other circuit interrupters such as contactors, motor starters, motor controllers and other load controllers) including a trip mechanism wherein locking of such mechanism is desirable.
Directional phrases used herein, such as, for example, left, right, front, back, clockwise, counterclockwise 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, 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 “linkage” refers to any known or suitable mechanism for interconnecting one component of a structure or assembly to another component thereof, in order to provide mechanical communication therebetween. For example, as discussed herein, the exemplary linkage is a flexible cable. However, it will be appreciated that any suitable linkage (e.g., without limitation, a wire; a chain; a spring; a number of interconnected links) could alternatively be employed.
As shown, the exemplary locking mechanism 42 includes a pivotal element 44, a mounting plate 46 structured to receive the locking mechanism 42 and secure it to the circuit breaker 32, an extension number 48 coupled to the pivotal element 44 and adapted to move therewith, and a flexible linkage 50 structured to interconnect the pivotal trip lever 40 and the extension member 48. The mounting plate 46 of the exemplary locking assembly 30 secures the locking mechanism 42 to one of the sides (e.g., 33) of the circuit breaker 32 just beneath the front cover (not shown in
Like the trip bar 6 and trip lever 12 of the locking assemblies discussed previously in connection with
Conversely, the exemplary flexible cable 50, as will be discussed in further detail hereinbelow, is adapted to couple at one end to a first opening 60 provided in the pivotal trip lever 40 and at the other end, to the extension member 48 of the locking mechanism pivotal element 44, in order to pivot the pivotal trip lever 40 counterclockwise against the aforementioned spring bias and lock it in the tripped open position when the locking mechanism 42 is locked (not shown in
As previously discussed, the pivotal trip lever 40 may be a separate component of the exemplary locking assembly 30, which is subsequently coupled to the trip bar 38 of the circuit breaker 32. In such a configuration, the pivotal trip lever 40 is preferably provided with the first opening 60 for attachment of the exemplary cable 50. However, it will be appreciated that, alternatively, the pivotal trip lever 40 may comprise an existing component of the circuit breaker 32, which may be subsequently modified (e.g., drilled), in order to create the desired first opening 60 therein. It will also be appreciated that new circuit breakers 32 may be made to include such first opening 60 in the pivotal trip lever 40. The first end 54 of the exemplary cable 50 includes a first eyelet 64 and is secured by a fastener 58, such as a screw or other suitable fastener (not shown), inserted through the first eyelet 64 into the first opening 60 of the pivotal trip lever 40. The second end 56 of the cable 50 includes a second eyelet 66 and is coupled to a second opening 62 provided in the extension member 48. Specifically, like the first end 54 of the exemplary cable 50, a fastener 58 is inserted through the second eyelet 66 of the second end 56 and is subsequently threaded or otherwise suitably secured within second opening 62 of the extension member 48. It will be appreciated that, while the exemplary extension member 48 is preferably a universally applicable component, useable with a wide variety of locks (e.g., 2, 20, 22), it may be necessary to customize (e.g., shorten; lengthen; bend) such member, in order that it functions properly with the particular type of lock being employed.
In operation, as previously discussed, the exemplary locking mechanism 42 rotates clockwise (to lock) and counterclockwise (to unlock) between locked and unlocked (
As shown in
It will, as previously discussed, be appreciated that the locking assembly 30 of the present invention could be employed in a variety of applications other than the example described and illustrated herein. One example of another circuit breaker application is with coded key interlocks, which are commonly used in security systems where it is important that only certain circuit breakers or combinations of circuit breakers are switched ON at the same time. In such a system, each coded key typically controls a specific group of circuit breakers. One or more of the exemplary locking assemblies could be employed within such a coded security system. As discussed hereinbefore, the invention is also readily applicable for use with a variety of electrical apparatus other than circuit breakers. It will also be appreciated that the locking assembly 30 may be arranged in any suitable configuration other than the one illustrated and described herein.
In summary, the exemplary locking assembly 30 provides a compliant flexible linkage 50 which is useable with a variety of commercially available locks (e.g., without limitation, 2, 20, 22), in order to convert rotational motion of the lock into a linear motion which in turn engages the trip component (e.g., 38, 40) of the circuit breaker 32 and locks it from a position outside of the circuit breaker 32 (e.g., from the front, right side 33 of the circuit breaker 32, of
While specific embodiments of the invention 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 invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.