Patent Application
20250157772
The following U.S. Patent Applications, each of which are filed concurrently with the present application, are incorporated by reference herein in their entireties for all purposes: Attorney Docket No. 2023P-166-US, titled “CIRCUIT BREAKER INTERLOCK MECHANISM,” Attorney Docket No. 2023P-167-US, titled “CIRCUIT BREAKER LINEAR LEVER AND TRIPPING FORK MECHANISM,” and Attorney Docket No. 2023P-175-US, titled “CIRCUIT BREAKER COMPENSATION BIMETAL OF A THERMAL TRIPPING MECHANISM.” Each of the applications describe features of a circuit breaker, all of which can be incorporated into a single circuit breaker to obtain the benefit of each of the described features.
Various embodiments of the present technology generally relate to tripping mechanisms in circuit breakers. More specifically, a tripping mechanism is disclosed that reduces the force needed to cause a trip related to a short circuit or over-current condition while avoiding trips related to physical shocks often experienced in industrial automation environments.
Circuit breakers are electrical switching devices designed to protect electrical circuits from potential damage that can be caused by short circuits or overloads. Circuit breakers may be implemented in industrial environments as components of electrical circuits. When a circuit breaker is turned on, an electrical connection is created by bringing sets of metal contacts into contact with one another to allow the flow of current through the circuit. When the device is turned off, the metal contacts are separated to interrupt the flow of current in the circuit. Circuit breakers may be manually or automatically operated to switch the device between states. Certain challenges have been faced with respect to achieving the appropriate sensitivity of circuit breakers in response to short circuits and overloads.
It is with respect to this general technical environment that aspects of the present disclosure have been contemplated. Furthermore, although a general environment is discussed, it should be understood that the described examples should not be limited to the general environment identified in the background.
This Overview is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Various embodiments of this disclosure relate to the mechanics used to stop current flow in a circuit breaker due to a short circuit or over-current condition. The mechanical components include a complex series of components that push a latch when an over-current or short circuit occurs. The latch holds a latch lever in an on position when the circuit breaker is on. Movement of the latch releases the latch lever, and the release of the latch lever causes a series of mechanical movements that separate the contacts of the circuit breaker to halt current flow. The point of contact between the latch and the latch lever sets the sensitivity of the circuit breaker to experiencing a trip. Accordingly, trips can occur due to short circuits and over-current based on the mechanical components of the circuit breaker that are designed to move the latch based on the relevant condition. Further, physical shocks (e.g., drops, bumps, and other physically jarring events) to the circuit breaker can cause a trip to occur if the sensitivity of the circuit breaker is too low. However, setting the sensitivity of the circuit breaker too high by requiring a large force to release the latch lever may make the circuit breaker insensitive to small movements of the components used to trip the circuit breaker based on short circuit and over-current conditions. To combat this potential issue, the described latch, latch lever, buckled shackle, and other movement components of the tripping mechanism are designed to reduce the force needed to trip the circuit breaker due to a short circuit or over-current condition while not creating over-sensitivity to physical jarring of the circuit breaker due to dropping, bumps, and other movement experienced in an industrial automation environment.
Some embodiments of the present disclosure include a tripping mechanism including a latch. The latch includes a pivoting body, a first extension disposed on the pivoting body at a first location, the first extension including a latch contact surface, and a second extension disposed on the pivoting body at a second location, the second extension including a trip component contact surface, wherein movement of a trip component in contact with the trip component contact surface causes the pivoting body to pivot about a first axis from a first position to a second position. Some embodiments include a latch lever include: a first end, a second end, and a bend disposed between the first end and the second end, a first rotational joint disposed at the bend and a second rotational joint disposed at the first end and spaced apart from the first rotational joint, a latch lever contact surface disposed at the second end, wherein the latch lever moves between an on position and a trip position, wherein movement of the latch to the second position causes the latch lever to move from the on position to the trip position. Some embodiments include a buckled shackle including a first section including a first end coupled to the second rotational joint, a second section including a second end coupled to a change lever, wherein the second section is integral with the first section, and a bend having an oblique angle between the first section and the second section, wherein the oblique angle is selected such that a force exerted by the latch lever contact surface on the latch contact surface falls within a sensitivity range when the latch lever is in the on position and the latch is in the first position.
Some embodiments include a joint arm having a first end and a second end, the first end being rotatably coupled to the first rotational joint and the second end being coupled to a toggle, wherein the toggle is operably coupled to a switch.
In some embodiments the buckled shackle bends around the first rotational joint when the latch lever is in the on position such that at least a portion of the first rotational joint is located between the first end and the second end of the buckled shackle.
In some embodiments in the change lever includes a fixed rotational joint, and wherein the change lever is coupled to a coiled spring that applies a force on the change lever when the latch lever is in the on position.
In some embodiments the sensitivity range is between 6 Newtons and 8 Newtons.
In some embodiments the oblique angle between the first section and the second of the buckled shackle is between 150 degrees and 170 degrees.
In some embodiments a tripping force exerted by the trip component contact surface on the first extension of the latch needed to move the latch from the first position to the second position is approximately 1.4 Newtons.
In some embodiments the trip component contact surface of the second extension of the latch is a thermal trip component contact surface, and wherein the latch further comprises a third extension disposed on the pivoting body at a third location, the third extension including a magnetic trip component contact surface, wherein movement of a magnetic trip component in contact with the magnetic component contact surface causes the pivoting body to pivot about the first axis from the first position to the second position.
Some embodiments include a third rotational joint disposed in the change lever, wherein the second end of the buckled shackle is rotatably coupled to the third rotational joint, and wherein a line from a rotational center of the second rotational joint to a rotational center of the third rotational joint is aligned with the first rotational joint in a direction perpendicular to a rotational plane of the first rotational joint when the latch lever is in the on position.
In some embodiments, when the latch lever is in the on position, no portion of the buckled shackle is aligned with the first rotational joint in a direction perpendicular to the rotational plane of the first rotational joint.
Some embodiments include a circuit breaker including: a stationary contact disposed in a circuit, a moving contact that moves between a first position in which the moving contact physically contacts the stationary contact and a second position in which the moving contact is separated from the stationary contact. Some embodiments include a switch selectable between an ON state in which the moving contact physically contacts the stationary contact and an OFF state in which the moving contact is separated from the stationary contact. Some embodiments include a rotary disk coupled to the switch and a tripping mechanism coupled to the rotary disk. In some embodiments the tripping mechanism includes a latch including a first extension having a latch contact surface and a second extension that receives a mechanical indication of a trip condition in the circuit breaker, wherein the latch moves in response to the mechanical indication to initiate a trip response. In some embodiments the tripping mechanism includes a latch lever including a first rotational joint, a second rotational joint spaced apart from the first rotational joint, and a latch lever contact surface that applies a force against the latch contact surface of the latch when the switch is in the ON state and the moving contact is in the first position. In some embodiments the tripping mechanism includes a buckled shackle including: a first section including a first end coupled to the second rotational joint, a second section including a second end coupled to a change lever, wherein the second section is integral with the first section, and a bend having an oblique angle between the first section and the second section, wherein the oblique angle is selected such that a force exerted by the latch lever contact surface on the latch contact surface falls within a sensitivity range when the latch lever is in the on position and the latch is in the first position.
These and other features and aspects of various examples may be understood in view of the following detailed discussion and accompanying drawings.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. While several embodiments are described in connection with these drawings, the disclosure is not limited to the embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents.
This disclosure relates to circuit breakers having a trip mechanism. Embodiments disclosed include a latch that may initiate a trip (e.g., a thermal trip or a magnetic trip). When the circuit breaker is on (i.e., allowing current flow), a contact surface on a latch lever applies a force against a contact surface of the latch, holding the latch lever in an ON position. A trip is initiated when the latch rotates and the contact surface of the latch no longer physically touches the contact surface of the latch lever. The latch lever may have a first rotational joint in which a joint arm is coupled to a toggle allowing an operator to turn the circuit breaker on and off. The latch lever is also coupled to a change lever via a buckled shackle, where the change lever pushes down on a rocker extension to open the circuit when the circuit breaker is OFF or in response to a tripping event (e.g., short circuit or over-current). A coiled spring applies a downward force on the change lever in the ON configuration. The buckled shackle in turn applies a force on a second rotational joint of the latch lever in the ON configuration.
The buckled shackle may have a bend to reduce the moment arm of the force the buckled shackle applies on the latch lever. The reduction in the moment-arm results in a reduced force between the latch and latch lever when the circuit breaker is on. As a result, lower tripping forces on the latch are required to initiate a trip, which allows for a greater sensitivity of response to short circuit and over-current conditions in the circuit. The configuration and design also reduces the internal forces of components in the tripping mechanism, which results in cost savings with respect to the materials and design of the components. Additionally, the bend in the buckled shackle allows the buckled shackle to avoid undesired contact between the buckled shackle and other components during a trip.
Referring now to the figures,
The latch 110 as shown in
The first extension 114 includes a latch contact surface 115. The latch contact surface 115 of the first extension 114 is in contact with the latch lever contact surface 123 when the circuit breaker 100 is in the ON configuration, as discussed in greater detail below. The second extension 113 includes a trip component contact surface 112, which is a thermal trip component contact surface in some embodiments. Movement of a thermal trip component in contact with the thermal trip component contact surface 112 causes the latch 110 to rotate counterclockwise (in
With reference to the coordinate system 101, the latch 110 rotates in the x-y plane with a rotational axis in the z direction. In some embodiments, the latch 110 is plastic. In other embodiments the latch 110 may be another material such as metal, composite material, or any combination of these materials.
The latch lever 120 may include a first rotational joint 127, a second rotational joint 129, and a contact surface 123. The axis of rotation of the first rotational joint 127 may be in the z direction, with the axis of rotation of the second rotational joint 129 also being in the z direction. The contact surface 123 of the latch lever 120 is in contact with the latch contact surface 115 when the trip mechanism is in the ON configuration shown in
The buckled shackle 130 couples the latch lever 120 with the change lever 160 in a manner discussed in greater detail below. The latch lever 120 is also coupled to the toggle 170 via a joint arm 171 (see
The change lever 160 pushes on the rocker arm 180 when switching from the ON configuration to the TRIP or OFF configurations. The change lever 160 thus translates the movement of the latch lever to a movement of the rocker arm 180 downward in the −y direction. The rocker arm 180 is in turn coupled to the rocker 190. Downward movement of the rocker arm 180 causes the rocker 190 to rotate, pushing down (in the −y direction) on the components holding conductive contacts together, which separates the conductive contacts to open the circuit, stopping the current flow. The operation of the rocker 190 is discussed in greater detail in relation to
When the circuit breaker 100 is in the ON configuration (as shown in
While one end of the buckled shackle 130 is coupled to the change lever 160, the other end of the buckled shackle 130 is coupled to the second rotational joint 129 of the latch lever 120. The force of the buckled shackle 130 on the latch lever 120 causes the latch lever 120 to exert a force against the latch 110. Specifically, the contact surface 123 of the latch lever 120 exerts a force against the contact surface 115 of the latch 110. The force between the latch contact surface 115 and the latch lever contact surface 123 is thus loaded, at least in part, by the coiled spring 150 via the change lever 160 and the buckled shackle 130. The buckled shackle 130 has a bent shape in some embodiments. The bent shape of the buckled shackle 130 allows for a reduction of the force between the latch contact surface 115 and the latch lever contact surface 123 when the tripping mechanism 125 is in the ON configuration. The reduction in force results from the bent-shape for the buckled shackle 130 providing for a shorter moment-arm of the force the buckled shackle 130 applies on the latch lever 120 about the first rotational joint 127. The bent shape and the moment-arm of the buckled shackle 130 are discussed in greater detail below.
In the ON configuration, as shown in
When the latch 110 rotates about the rotational joint 119 (counterclockwise in the view in
The latch 110 may have a normal position (shown in
During thermal trips, the thermal trip extension 113 may be pushed to the left by a thermal trip component (such as a compensation bimetal component) contacting the thermal trip component contact surface 112, thus rotating the latch 110 to the trip position. During magnetic trips, the magnetic trip extension 117 may be pushed down in the −y direction by a magnetic trip component contacting the magnetic trip component contact surface 118, thus rotating the latch 110 to the trip position. The latch 110 may thus initiate both thermal trips and magnetic trips in the circuit breaker 100. While described as thermal and magnetic tripping mechanisms, any other type of mechanism can be used to detect trips including, for example, electronic and microprocessor mechanisms.
In the ON configuration of the circuit breaker 100, the latch lever contact surface 123 applies a normal force against the latch contact surface 115. A frictional force between contact surfaces 115 and 123 results from the normal force between the contact surfaces 115 and 123, as well as the coefficient of friction. The frictional force thus resists rotation of the latch 110 from the normal position to the trip position. A specified tripping force is thus required to overcome the frictional forces and initiate a trip. See further discussion in relation to
In the OFF position shown in
An operator may transition the circuit breaker from the ON configuration in
When the circuit breaker is in the ON position shown in
The latch lever 120 is rotatably coupled to the buckled shackle 130 at the second rotational joint 129. The buckled shackle includes a first end 131A and a second end 131B. In some embodiments, the first end 131A and the second end 131B are integral such that they form a single unitary piece without detachable parts. The buckled shackle also includes a bend 131C between the first end 131A and the second end 131B. The first end 131A, the second end 131B and the bend 131C of the buckled shackle 130 form a unitary element according to some embodiments. The first end 131A of the buckled shackle 130 is rotatably coupled to the second rotational joint 129 of the latch lever 120. The second end 131B of the buckled shackle 130 is rotatably coupled to the rotational joint 163 of the change lever 160. The buckled shackle 130 may be generally tubular such that cross sections of the buckled shackle 130 are circular. In some embodiments, the buckled shackle 130 is metal. In other embodiments the buckled shackle 130 may be another material such as plastic, composite material, or any combination of these materials. While a unitary buckled shackle 130 is described above, it is noted that other embodiments the buckled shackle may include multiple parts attached to each other.
The first end 131A of the buckled shackle 130 exerts a force on the second rotational joint 129 when the tripping mechanism 125 is in the ON configuration. The buckled shackle 130 may exert a general rightward force on the second rotational joint 129 in the ON configuration. The buckled shackle 130 has a bend 131C between the first section 131A and the second section 131B. The bend 131C of the buckled shackle 130 is selected such that a force between the latch lever contact surface 120 and the latch contact surface 115 falls within a sensitivity range when the tripping mechanism is in the ON configuration. In some embodiments, the sensitivity range is between 6 Newtons to 8 Newtons. Specifically, the bend 131C in the buckled shackle 130 is selected to reduce a moment-arm of the force exerted by the buckled shackle 130 on the latch lever 120 about the first rotational joint 127. This in turn results in a lowering of the force exerted by the contact surface 123 of the latch lever 120 against the contact surface 115 of the latch 110. This reduction in the force between the contact surfaces 115 and 123 allows the latch 110 to be more sensitive. Specifically, lower tripping forces are required to rotate the latch 110 and initiate a trip.
In
The bend 131C allows the buckled shackle 130 to be offset from the first rotational joint 127 in the ON configuration as shown in
The first section 131A has a centerline 135A and the second section 131B has a centerline 135B. The first section centerline 135A and the second section centerline 135B meet at the bend 131C. The angle 139 is the angle between the first section centerline 135A and the second section centerline 135B.
The angle 139 may be selected to reduce the length of the dashed line 133 representing the moment-arm. This reduction in the length of the moment-arm results in a reduced force of the latch lever 120 against the latch 110 in the ON configuration. The angle 139 at the bend 131C allows the moment-arm of the buckled shackle 130 about the first rotational joint 127 to be reduced, while avoiding contact with other components of the circuit breaker 100 during transitions between configurations. In some examples, the angle 139 is approximately 160 degrees. In other examples, the angle 139 may be between 150 and 170 degrees. Note that if the buckled shackle 130 were straight, the length of the moment-arm would be increased as it would need to avoid collision with the other components extending from rotational joint 127.
The tripping force, the force on the latch 110 required to initiate a trip (at the thermal tripping extension 113 or the magnetic tripping extension 117), may be predetermined to be within a zone of sensitivity. While lower tripping forces provide certain benefits such as increased sensitivity, the tripping force may be selected to be high enough to avoid unwanted trips, such as trips resulting from vibrations in the industrial environment. The tripping force depends on the force between the latch 110 and latch lever, 120, the surface area of the contact between these components, and the coefficient of friction between the contact surfaces 115, 123. In some embodiments the coefficient of friction between the contact surfaces 115 and 123 may be 0.2. In some embodiments the tripping force is approximately 1.4 Newtons.
In some embodiments, the force between the latch 110 and the latch lever 120 is approximately 6.8 Newtons in the ON configuration, and the tripping force is approximately 1.4 Newtons. However, in other embodiments, the force between the latch lever 120 and the latch 110 may be between 6 and 8 Newtons, and the tripping force may be between 1 and 1.8 Newtons.
In addition to reducing the force between the latch 110 and the latch lever 120, the reduced torque on the latch lever 120 may reduce strain on components within the tripping mechanism 125. This may provide for cost savings in the selection of materials and the design of the components in the tripping mechanism 125. These cost savings may be achieved in part by including the buckled shackle 130 having a bend 131C.
The circuit breaker 100 includes a switch 103, a rotary disk 105, a toggle wheel 107, a plunging spring 199, a plunging element 193, moving contacts 195, and stationary contacts 197.
The switch 103 is a rotary switch on an outside surface of the circuit breaker that, in some examples, can be rotated between three settings—“ON,” “OFF,” and “TRIP.” In some examples, the switch 103 rotates ninety degrees between “ON” and “OFF.” The switch 103 may be integral with the rotary disk 105 such that the rotary disk 105 rotates with the switch 103.
The rotary disk 105 interfaces with the toggle wheel 107, which in turn interfaces with the toggle 170. The toggle is thus indirectly coupled to the rocker 190 via the tripping mechanism 125 as discussed in detail above. The rocker 190 is configured to open the circuit by separating the moving contacts 195 from the stationary contacts 197 via the plunging element 193. The plunging element 193 may be biased upward by the plunging spring 199. The rocker 190 is responsive to upward and downward movement (with respect to the y direction) of the rocker arm 180, as discussed above.
In embodiments of the present technology, various components of circuit breaker 100 are comprised of metal, plastic, a composite material, or any combination of these.
In the example of
In the example of
In the example of
When the switch 103 is stopped from rotating to the “OFF” position 615 by interlock components, contact welding has occurred. Thus, when in the “TRIP” position 615 in a contact welding scenario, the moving contacts 195 (see
Power source 905 is representative of any device or electrical component delivering power into circuit 900. Power source 905 may be an independent voltage source, a dependent voltage source, or other type of voltage source. Examples of such power sources include generators, photovoltaic cells, thermopiles, primary-cell batteries, a power grid, and the like. Power source 905 creates electrical voltage that causes current to flow through circuit 900 via one or more connecting wires or other connection components. Load 915 is representative of any device or electrical component that consumes electrical energy. Load 915 may represent a resistive load, inductive load, capacitive load, or combined load. Examples of loads include electric lamps, air conditioners, motors, resistors, heaters, processors, precision manufacturing equipment, data servers, pumps, fans, generators, robotic machinery, industrial automation controllers, and the like. Circuit breaker 910 is representative of any circuit breaker in accordance with the technology disclosed herein. For example, circuit breaker 910 may be representative of circuit breaker 100 from the preceding figures. Circuit breaker 910 may alternatively be representative of a circuit breaker system that differs from circuit breaker 100 but includes the tripping mechanism 125 including the buckled shackle 130, latch lever 120, and latch 110 as described above.
In accordance with the example of
The above description and associated figures teach the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects of the best mode may be simplified or omitted. The following claims specify the scope of the invention. Note that some aspects of the best mode may not fall within the scope of the invention as specified by the claims. Thus, those skilled in the art will appreciate variations from the best mode that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples described below, but only by the claims and their equivalents.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “include,” “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof means any connection or coupling, either direct or indirect, between two or more elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number, respectively. The word “or” in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
The phrases “in some embodiments,” “according to some embodiments,” “in the embodiments shown,” “in other embodiments,” and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one implementation of the present technology and may be included in more than one implementation. In addition, such phrases do not necessarily refer to the same embodiments or different embodiments.
The above Detailed Description is not intended to be exhaustive or to limit the technology to the precise form disclosed above. While specific examples of the technology are described for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. Further any specific numbers noted herein are only examples: alternative implementations may employ differing values or ranges.
The teachings of the technology provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various examples described above can be combined to provide further implementations of the technology. Some alternative implementations of the technology may include not only additional elements to those implementations noted above, but also may include fewer elements.
These and other changes can be made to the technology in light of the above Detailed Description. While the above description describes certain examples of the technology, and describes the best mode contemplated, no matter how detailed the above appears in text, the technology can be practiced in several ways. Details of the system may vary considerably in its specific implementation, while still being encompassed by the technology disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the technology should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the technology with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the technology to the specific examples disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the technology encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the technology under the claims.
To reduce the number of claims, certain aspects of the technology are presented below in certain claim forms, but the applicant contemplates the various aspects of the technology in any number of claim forms. For example, while only one aspect of the technology is recited as a computer-readable medium claim, other aspects may likewise be embodied as a computer-readable medium claim, or in other forms, such as being embodied in a means-plus-function claim. Any claims intended to be treated under 35 U.S.C. § 112(f) will begin with the words “means for” but use of the term “for” in any other context is not intended to invoke treatment under 35 U.S.C. § 112(f). Accordingly, the applicant reserves the right to pursue additional claims after filing this application to pursue such additional claim forms, in either this application or in a continuing application.
