Patent Grant
10217591
The disclosure relates to circuit breakers for interrupting power from an electrical power supply, and more particularly to toggle link apparatus for circuit breakers, and assemblies and methods utilizing such toggle link apparatus.
Circuit breakers are commonplace for use in residential and commercial applications. Certain circuit breakers, as shown in
Accordingly, a need therefore exists to provide improved circuit breakers and trip mechanism assemblies and toggle links that provide improved performance.
According to one aspect, an improved toggle link of a circuit breaker is provided. The toggle link includes a link body having a pivot end and an engagement end opposite the pivot end, the engagement end including an open-ended slot including a pivot feature and a stop feature configured to interface with a toggle pin.
According to another aspect, a toggle link assembly of a circuit breaker is provided. The toggle link assembly includes a first toggle link including a link body having a pivot end coupleable with a cradle and an engagement end opposite the pivot end, the engagement end including an open-ended slot including a pivot feature and a stop feature, and a second toggle link including a first end engageable with a crossbar assembly and a second end including a toggle pin, the toggle pin received in the open-ended slot.
According to a third aspect, a method of operating a trip mechanism assembly of a circuit breaker is provided. The method includes providing the trip mechanism having a cradle, a latch configured to delatch the cradle, a crossbar assembly including moveable contact fingers, a first toggle link including a link body having a pivot end coupled to the cradle and an engagement end opposite the pivot end, the engagement end including an open-ended slot including a pivot feature and a stop feature, and a second toggle link including a first end coupled to the crossbar assembly and a second end including a toggle pin, the toggle pin received in the open-ended slot, and restraining to the motion of the cradle during a tripping event with the stop feature.
Still other aspects, features, and advantages of the disclosure may be readily apparent from the following detailed description wherein a number of example embodiments are described and illustrated, including the best mode contemplated for carrying out the invention. The several details of the disclosure may be modified in various respects, all without departing from the scope of the invention. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. The disclosure covers all modifications, equivalents, and alternatives falling within the scope of the claims.
The drawings, described below, are for illustrative purposes only and are not necessarily drawn to scale. The drawings are not intended to limit the scope of the invention in any way.
Reference will now be made in detail to the example embodiments of this disclosure, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
In a typical trip mechanism 100 of a circuit breaker, when the circuit breaker in an “ON” position, the trip mechanism 100 is latched and a crossbar assembly 114 is rotated to close the movable contact fingers 115 including the moveable contacts 115C against line side contacts (not shown), which may be one or more fixed electrical contacts and thus connect the electrical load to the source of electrical power. During a tripping event, such as from a short circuit, a trip bar of the trip mechanism assembly will release the latch 116, which in turn will delatch the cradle 104. Upon being delatched, a mechanism spring (not shown) that is coupled to the cradle 104 will cause the crossbar assembly 114 to rotate away from the fixed contacts, which separates the electrical contacts and opens the protected circuit. The crossbar assembly 114 will continue to rotate under the force of the mechanism spring until the movable contact fingers 115 are stopped, such as by a stop mechanism (e.g., a frame tie and possibly an absorber).
In the initial stages of tripping, the toggle link assembly including the upper toggle link 102 and lower toggle link 108, and the cradle 104 rotate together with the crossbar assembly 114. However, in some instances, the kinetic energy and momentum of the upper toggle link 102 and cradle 104 imparted by the mechanism spring (not shown), can cause the upper toggle link 102 and the coupled cradle 104 to continue their rotation. The rotation can continue until either the mechanism spring absorbs all of this momentum, or in some cases, such as where the mechanism spring may have been weakened, the cradle 104 can be stopped by a collision with some other part of the circuit breaker, such as, the underside of the operating handle (not shown).
The operating handle allows the operator to manually open or close the circuit breaker. In other instances, this extreme cradle rotation can be beyond (e.g., above) the upper location of the latch 116. In these instances, the cradle 104 can become jammed on an end of the latch 116 as shown in
In view of the problems of the prior art toggle link assemblies and trip mechanism assemblies of circuit breakers, embodiments of the disclosure provide an improved toggle link assembly and trip mechanism assembly including the toggle link assembly. The improved trip mechanism assembly provides a cradle rotation limit function. In particular, the trip mechanism assembly includes an improved toggle link assembly that includes a stop feature. In some embodiments, a stop feature can be added to the upper toggle link and the improved toggle link assembly functions to limit rotational motion of the cradle. The stop feature may prevent the cradle from rotating above a predefined position within the internal confines of the circuit breaker. For example, the stop feature may prevent the cradle from becoming positioned above a top of the latch, so that jamming or locking up of the trip mechanism assembly is avoided or minimized. Moreover, the toggle link assembly including a stop feature may prevent the cradle from colliding with other circuit breaker components, such as, the underside or part of the operating handle.
One advantage of the improved trip mechanism assembly and toggle link assembly is that a limit stop feature can be accommodated without increasing a size of the circuit breaker. In some embodiments, the stop feature is included in the upper toggle link. Further details and aspects of trip mechanism assemblies, toggle link assemblies, toggle links, and methods of operating a trip mechanism assembly of a circuit breaker are provided, and will be described below in connection with
The trip mechanism assembly 200 may further include a crossbar assembly 114 including one or more moveable contact fingers 115. The number of moveable contact fingers 115 may be between 1 and 8 per pole and a separate crossbar assembly 114 may be provided for each pole. The moveable contact fingers 115 may themselves be moveable (e.g., pivotable) relative to the crossbar housing 114H. An example of the construction of the crossbar assembly 114 is further described in U.S. Pat. No. 8,901,446 to Fong et al. entitled “Limit Stop Apparatus, Circuit Breakers Including Limit Stops, And Methods Of Using Same.” The crossbar assembly 114 is pivotal about a fixed axis 220, shown as a dot in
Again referring to
In more detail, the first toggle link 202 includes a link body 202B having a pivot end 202P. In the configuration shown, the pivot end 202P can be coupled to the cradle 104 and include an engagement end 202E opposite from the pivot end 202P. The engagement end 202E includes an open-ended slot 206 including a pivot feature 206P and a stop feature 226. The second toggle link 108 includes a first end 228 that in the configuration shown can be coupled to the crossbar assembly 114 and has a second end 230 including a toggle pin 110. The toggle pin 110 can be slidably received in the open-ended slot 206. In the depicted embodiment, the pivot feature 206P may comprise a semi-circular surface slightly larger than a diameter of the toggle pin, which may function as a bearing surface.
As best shown in
In one aspect, the disclosure provides a toggle link 202 of a circuit breaker. An example of the toggle link 202 is best shown in
The toggle link 202 may include a configuration wherein the open-ended slot 206 includes a first slot region 332 extending from the pivot feature 206P to the stop feature 226. This first slot region 332 provides a first channel for the toggle pin 110 to move within. The first slot region 332 may be aligned substantially along a line of action LOA. The LOA may be a line or slight arc that the toggle pin 110 will naturally take upon separation of the first toggle link 202 from the second toggle link 108 upon over-rotation of the cradle 104. As the toggle pin 110 contacts the stop feature 226, further separation between the first toggle link 202 and the second toggle link 108 is halted, and thus further rotation of the cradle 104 is stopped. The stop feature 226 may be positioned at a location such that a distance D between the pivot portion 206P and the stop feature 226 along the line of action LOA is between about 1.9 mm and about 6.8 mm, for example. Other values of the distance D may be used, depending upon the location and sizes of the latch 116 and latch portion 104L. In the depicted embodiment, the stop feature 226 comprises an angled surface formed on a side of the open-ended slot 206. For example, as shown in
The open-ended slot 206 of the first toggle link 202 can further include a second slot region 334 intersecting with and extending away from the first slot region 332. The second slot region 334 can extend along a non-straight path from the stop feature 226 to an open end 206O of the open-ended slot 206. Thus, in the configuration shown, the open-ended slot 206 comprises a first slot region 332 extending from the pivot feature 206P to the stop feature 226, and a second slot region 334 extending from the stop feature 226 to an open end 206O of the open-ended slot 206. In the depicted embodiment, a center of the open end 206O can be positioned at a lateral offset distance O from the line of action LOA passing between the pivot feature 206P and the stop feature 226. In some embodiments, the lateral offset distance O can be greater than 2.2 mm, and between about 2.2 mm and about 7.1 mm in some embodiments. Other lateral offset distances O can be used.
In the depicted embodiment, the second slot region 334 can include a curved surface 336 on one side of the open-ended slot 206 having a radius R of between about 5.6 mm and about 10.0 mm. Other values of radius R can be used. The curved surface 336 may extend through an arc AA of between about 45 degrees and about 75 degrees, for example. In the depicted embodiment, the second slot region 334 can include an opposed surface 338 that is opposed to the curved surface 336. Opposed surface 338 may also include an arc thereon.
The values for D, O, and R may be dependent on the diameter of the toggle pin 110 and where the toggle pin 110 pivots with the first toggle link 202. A 3-pole circuit breaker designed for 800 amp to 1200 amp frames can use a 5.0 mm diameter of the toggle pin 110, but smaller (e.g., circuit breakers designed for 100 A frame) could use a diameter of the toggle pin 110 of 2.5 mm. The range of values for A and AA are independent of the diameter of the toggle pin 110. One example embodiment of a 3-pole circuit breaker includes D=4.7 mm, O=4.35 mm, R=8.7 mm, AA=60 degrees, and A=60 degrees. Other values may be used.
Now referring to
The method 600 further comprises in block 604 restraining the rotational motion of the cradle (e.g., cradle 104) during a tripping event with the stop feature (e.g., stop feature 226). A tripping event is any event that causes release of the cradle 104 (e.g., a short circuit or other condition causing the latch 116 to delatch the cradle 104). As discussed above the degree of rotation of the cradle 104 is limited to a predefined amount by contact of the toggle pin (e.g., toggle pin 110) with the stop feature (e.g., stop feature 226). Thus, contact of the cradle (e.g., cradle 104) with the operating handle (e.g., operating handle 550) is minimized or avoided. Moreover, jamming of the cradle 104 with the latch 116 can also be minimized or avoided.
A person of ordinary skill in the art should readily appreciate that the embodiments described herein are susceptible of broad utility and application. Many embodiments and adaptations other than those described herein, as well as many variations, modifications, or equivalent arrangements, will be apparent from, or reasonably suggested by, the disclosure, without departing from the substance or scope of the claims. This disclosure is not intended to limit the invention to the particular apparatus, devices, assemblies, systems, or methods disclosed herein, but, to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5449871 | Batteux | Sep 1995 | A |
| 6798324 | Richter | Sep 2004 | B2 |
