Mechanical interlock for circuit breaker

Abstract

The application relates to a mechanical interlocking device for a circuit breaker, characterized by comprising a side plate, a top plate, an output shaft assembly, a transmission module, a limiting plate, an interlocking plate and a closing trip assembly; the mechanical interlocking device meets the protection requirements in a power system, meets the requirement that when a three-position switch is operated manually for isolation or grounding, the circuit breaker must be always in an open position and cannot be operated for closing, and meets the requirement that when the circuit breaker is in a closing position, the three-position switch cannot be operated for isolation or grounding. In addition, the mechanical interlocking device also meets the requirement that the circuit breaker cannot be closed again in a closing state, so that the interlocking device between the three-position switch and the circuit breaker enables the circuit breaker to have a closing interlocking function.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker operating mechanism technology, and in particular to a mechanical interlocking device for circuit breakers. Background Technology

[0002] According to the "five protections" requirements of the power system: for switchgear equipped with three-position switches, when the three-position switch is being manually isolated or grounded, the circuit breaker must always be in the open position and cannot be closed; when the circuit breaker is in the closed position, the three-position switch cannot be isolated or grounded. Furthermore, it is required that the circuit breaker cannot be closed again when it is in the closed position. Therefore, for protection and ease of operation, an interlocking device must be installed between the three-position switch and the circuit breaker, and the circuit breaker should also have a closing interlocking function.

[0003] Existing mechanical interlocking devices for switchgear, such as the Chinese invention patent patent with application publication number CN111192775A and application publication date of May 22, 2020—Switchgear and its interlocking device—use a multi-component series connection and multiple hinges for the interlocking design between the three-position mechanism and the circuit breaker mechanism, resulting in large cumulative errors and poor reliability. In addition, its interlocking function is imperfect and does not have the interlocking function to prevent secondary closing of the circuit breaker after closing. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a mechanical interlocking device for circuit breakers, which can solve the problem of safety accidents caused by poor design of general circuit breaker interlocking functions and human error.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: a mechanical interlocking device for circuit breakers, the innovation of which is: including a side plate, a top plate, an output shaft assembly, a transmission module, a limit plate, an interlocking plate, and a closing tripping assembly; The side plate is arranged vertically and has several shaft holes. The shaft holes include an output shaft mounting hole, a first rotary shaft mounting hole, and a second rotary shaft mounting hole. Screws are also provided on the side plate. A first rotary shaft is mounted at the first rotary shaft mounting hole via a rotary bearing, and a second rotary shaft is mounted at the second rotary shaft mounting hole via a rotary bearing. The top plate is disposed on the top of the side plate perpendicular to the direction of the side plate; the top plate has a through hole for accommodating the end of the transmission module and a waist-shaped hole for the transmission plate. The output shaft assembly includes an output shaft and an outer crank arm; the output shaft is a cylindrical structure with splines and is mounted on the output shaft mounting hole of the side plate via a slewing bearing; the outer crank arm is provided with a keyway and nested on the output shaft, and a slewing pin is also provided on the outer crank arm; The transmission module includes a first transmission plate and a second transmission plate; the bottom end of the first transmission plate is connected to a rotary pin on the outer crank arm, and the first transmission plate is parallel to the side plate; a transmission pin is provided at the top end of the first transmission plate; the bottom end of the limiting plate is misaligned with the transmission pin at the top end of the first transmission plate, and a gap is left between the limiting plate and the first transmission plate; the top end of the limiting plate has a tapered section, and the outer diameter of the tapered section gradually decreases from the bottom end to the top end of the limiting plate; the top end of the limiting plate passes through the limiting plate through hole; the second transmission plate includes a crank arm section and a cylindrical section, the cylindrical section is connected to one end of the crank arm section, and the cylindrical section passes through the second transmission plate waist-shaped hole on the top plate; the crank arm section has an L-shaped structure, and the corner position of the crank arm section is fixedly connected to the first rotary shaft, the crank arm section rests on the transmission pin connecting the first transmission plate and the limiting plate, and the other end of the crank arm section is connected to the screw on the side plate through a return spring; The interlocking plate is positioned above the top plate. The side of the interlocking plate has a V-shaped groove that mates with the cylindrical section. The interlocking plate also has a guide groove that mates with the top of the limiting plate. The side of the guide groove has a notch that allows the tapered section at the end of the limiting plate to pass through completely. The maximum width of the tapered section at the top of the limiting plate is greater than the width of the guide groove of the interlocking plate, and the minimum width of the tapered section at the top of the limiting plate is less than the width of the guide groove. The closing tripping assembly includes a closing lever, a torsion spring, a closing push plate, and a locking tongue. The closing lever is mounted on a second rotating shaft via a slewing bearing, with one end of the closing lever located on the side of the first rotating shaft. The torsion spring is nested on the second rotating shaft, with one end connected to the closing lever and the other end connected to the circuit breaker. The torsion force of the torsion spring presses the closing lever against the side of the first rotating shaft. The closing push plate is bolted to the closing lever. The locking tongue is locked to the side of the first rotating shaft by a locking tongue screw and can rotate with the first rotating shaft. The locking tongue cooperates with the closing push plate to limit the closing push plate.

[0006] Furthermore, the lower surface of the end of the crank arm section of the second transmission plate that connects to the return spring is provided with an inclined surface that cooperates with the transmission pin.

[0007] Furthermore, the locking tongue is provided with a waist-shaped hole, and the locking tongue screw passes through the waist-shaped hole and is connected to the first rotating shaft.

[0008] The advantages of this invention are: 1) In this invention, when the circuit breaker is in the open position, the interlocking plate of the three-position isolating grounding switch is not constrained by the limiting plate of the mechanical interlocking device, and the interlocking plate can move left and right, allowing the three-position isolating grounding switch to perform isolation or grounding operations; simultaneously, the locking tongue of the mechanical interlocking device disengages from the closing tripping assembly, allowing the circuit breaker to perform a closing operation; when the circuit breaker is in the open position, and the three-position isolating grounding switch is performing isolation or grounding operations, the interlocking plate of the three-position isolating grounding switch drives the second transmission plate of the mechanical interlocking device, causing the locking tongue to engage with the closing tripping assembly, preventing the circuit breaker from performing a closing operation; when the circuit breaker moves from the open position to the closed position, the lower end of the limiting plate of the mechanical interlocking device inserts into the guide groove notch of the interlocking plate of the three-position isolating grounding switch, restricting the left and right movement of the interlocking plate, preventing the three-position isolating grounding switch from performing isolation or grounding operations; simultaneously, the locking tongue of the mechanical interlocking device restricts the closing tripping assembly from performing closing tripping, preventing the circuit breaker from performing a secondary closing operation. Attached Figure Description

[0009] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0010] Figure 1 This is a three-dimensional structural diagram of a mechanical interlocking device for a circuit breaker according to the present invention.

[0011] Figure 2 This is a schematic diagram of the interlocking plate position when the three-position switch of the mechanical interlocking device for a circuit breaker is in the closed and locked state according to the present invention.

[0012] Figure 3 This is a schematic diagram of the circuit breaker closing and three-position switch closing interlocking states of a mechanical interlocking device for a circuit breaker according to the present invention.

[0013] Figure 4 This is a schematic diagram of the interlocking plate position when the three-position switch of a mechanical interlocking device for a circuit breaker is closed but not locked, according to the present invention.

[0014] Figure 5 This is a schematic diagram of the circuit breaker tripping and three-position switch closing unlocked states of a mechanical interlocking device for a circuit breaker according to the present invention.

[0015] Figure 6 This is a schematic diagram of the interlocking plate position of a mechanical interlocking device for a circuit breaker in the isolation or grounding state of the three-position switch according to the present invention.

[0016] Figure 7 This is a schematic diagram of the circuit breaker tripping, three-position switch isolation, or grounding state of a mechanical interlocking device for a circuit breaker according to the present invention.

[0017] Figure 8This is a schematic diagram of the timing analysis of the circuit breaker closing and locking process of a mechanical interlocking device for circuit breakers according to the present invention.

[0018] Figure 9 This is a schematic diagram of the second transmission plate structure of a mechanical interlocking device for a circuit breaker according to the present invention.

[0019] Figure 10 This is a schematic diagram of the locking tongue structure of a mechanical interlocking device for a circuit breaker according to the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] like Figure 1 The mechanical interlocking device for a circuit breaker shown includes a side plate 1, a top plate 2, an output shaft assembly 3, a transmission module 4, a limit plate 5, an interlocking plate 6, and a closing tripping assembly 7.

[0023] Side plate 1 is arranged vertically, and several shaft holes are opened on side plate 1; the shaft holes include output shaft mounting holes, first rotary shaft mounting holes and second rotary shaft mounting holes; screws are also provided on side plate 1; a first rotary shaft 11 is installed at the first rotary shaft mounting hole through a rotary bearing, and a second rotary shaft 12 is installed at the second rotary shaft mounting hole through a rotary bearing.

[0024] The top plate 2 is set on the top of the side plate 1 perpendicular to the side plate 1; the top plate 2 has a limiting plate through hole 21 to accommodate the end of the transmission module 4 and a waist-shaped hole 22 of the transmission plate.

[0025] The output shaft assembly 3 includes an output shaft 31 and an outer crank arm 32; the output shaft 31 is a cylindrical structure with splines and is mounted on the output shaft mounting hole of the side plate via a slewing bearing; the outer crank arm 32 is provided with a keyway and nested on the output shaft 31, and a slewing pin is also provided on the outer crank arm 32; The transmission module 4 includes a first transmission plate 41 and a second transmission plate 42; the bottom end of the first transmission plate 41 is connected to a rotary pin on the outer crank arm 32, and the first transmission plate 41 is parallel to the side plate 1; a transmission pin 43 is provided at the top end of the first transmission plate 41; the bottom end of the limiting plate 5 is misaligned with the transmission pin 43 at the top end of the first transmission plate 41, and a gap is left between the limiting plate 5 and the first transmission plate 41; the top end of the limiting plate 5 has a tapered section, and the outer diameter of the tapered section gradually decreases from the bottom end to the top end of the limiting plate 5; the top end of the limiting plate 5... The end passes through the through hole 21 of the limiting plate; the second transmission plate 42 includes a crank arm section 421 and a cylindrical section 422. The cylindrical section 422 is connected to one end of the crank arm section 421 and passes through the waist-shaped hole 22 of the second transmission plate on the top plate; the crank arm section 421 has an L-shaped structure, and the corner position of the crank arm section 421 is fixedly connected to the first rotating shaft 11. The crank arm section 421 rests on the transmission pin 43 that connects the first transmission plate 41 and the limiting plate 5, and the other end of the crank arm section 421 is connected to the screw on the side plate through the return spring 44.

[0026] The interlocking plate 6 is located above the top plate. The side of the interlocking plate 6 has a V-shaped groove that mates with the cylindrical section. The interlocking plate 6 has a guide groove 61 that mates with the top of the limiting plate. The side of the guide groove 61 has a notch that allows the tapered section at the end of the limiting plate 5 to pass through completely. The maximum width of the tapered section at the top of the limiting plate 5 is greater than the width of the guide groove of the interlocking plate. The minimum width of the tapered end at the top of the limiting plate 5 is less than the width of the guide groove.

[0027] The closing trip assembly 7 includes a closing lever 71, a torsion spring 72, a closing push plate 73, and a locking tongue 74. The closing lever 71 is mounted on the second rotating shaft 12 via a slewing bearing, with one end of the closing lever 71 located on the side of the first rotating shaft 11. The torsion spring 72 is nested on the second rotating shaft, with one end of the torsion spring 72 connected to the closing lever and the other end connected to the circuit breaker. The torsion force of the torsion spring 72 presses the closing lever 71 against the side of the first rotating shaft 11. The closing push plate 73 is bolted to the closing lever 71. The locking tongue 74 is locked to the side of the first rotating shaft 11 by a locking tongue screw 75 and can rotate with the first rotating shaft 11. The locking tongue 74 cooperates with the closing push plate 73 to limit the closing push plate 73.

[0028] The lower surface of the end of the crank arm section 421 of the second transmission plate 42, which connects to the return spring 44, is provided with an inclined surface that cooperates with the transmission pin 43.

[0029] The locking tongue 74 is provided with a waist-shaped hole, and the locking tongue screw 75 passes through the waist-shaped hole and is connected to the first rotating shaft 11.

[0030] The working principle of this invention is as follows: In the initial state, the circuit breaker is in the closed position, and the three-position switch is in the closed position, such as... Figure 2-3 As shown; because the widest part of the tapered end of the limit plate is greater than the width of the guide groove, the opening of the isolation and grounding operation holes on the three-position switch panel is restricted, and the three-position switch cannot perform isolation or grounding operations; in addition, when the outer crank arm is in the closed position, the locking tongue is locked with the closing push plate due to the position of the transmission pin, which restricts the clockwise rotation of the closing push plate, and the circuit breaker cannot perform a secondary closing operation; When the circuit breaker moves from the closed position to the open position, such as Figure 4-5 As shown; when the outer crank arm is in the open position, the second transmission plate rotates counterclockwise along with the first rotating shaft until the inclined surface of the second transmission plate contacts the transmission pin; simultaneously, the locking tongue fixed on the first rotating shaft rotates counterclockwise along with the first rotating shaft, the locking tongue's latching surface moves away from the closing push plate, the locking latching is opened, and the circuit breaker can be closed. Furthermore, constrained by the hinge connection between the first transmission plate, the limit plate, and the outer crank arm, the limit plate moves downwards, and the tapered section at the top of the limit plate enters the guide groove of the interlocking plate. Since the minimum width of the tapered section of the limit plate is less than the width of the horizontal guide groove of the interlocking plate, the three-way interlocking plate can move left and right at this time, thereby allowing the isolation and grounding operation holes on the three-position switch panel to open, and the three-position switch can be isolated or grounded.

[0031] When the interlocking plate is Figure 4 State movement to Figure 6 In this state, the isolation or grounding operation hole on the three-position switch panel is opened, and the three-position switch performs isolation or grounding operation; during the leftward movement of the interlock plate, the inclined surface on the interlock plate continuously pushes the cylindrical section of the second transmission plate forward, forcing the second transmission plate and the first rotating shaft to rotate clockwise together until the V-groove on the side of the interlock plate is tangent to the cylindrical section of the second transmission plate; Figure 7 As shown, at this time, the inclined surface of the second transmission plate is disengaged from the transmission pin and no longer in contact; the locking tongue fixed on the first rotating shaft rotates clockwise with the first rotating shaft, and the locking tongue engages with the closing push plate, restricting the clockwise rotation of the closing push plate. At this time, the circuit breaker cannot perform the closing operation.

[0032] It should be added that when the circuit breaker moves from the open position to the closed position, that is... Figure 5 Exercise Figure 3 The circuit breaker operates as follows: after the closing driver is energized, it drives the closing lever to rotate clockwise to complete the closing trip. After tripping, the internal structural components of the circuit breaker drive the output shaft to rotate through torque transmission, thereby moving the outer crank arm from the open position to the closed position. The first transmission plate, hinged on the outer crank arm, drives the second transmission plate and the first rotating shaft to rotate clockwise together with the movement of the outer crank arm. The locking tongue fixed on the first rotating shaft also rotates clockwise with the rotating shaft. At the same time, after the tripping is completed, the closing trip assembly rotates clockwise and counterclockwise under the action of the torsion spring to reset. Figure 8 As shown, if the torsion spring force is not designed properly and the closing trip assembly does not reset in time, the closing trip assembly, which is resetting, will collide with the locking assembly that is engaging. Furthermore, due to the obstruction of the locking assembly structure, the closing trip assembly cannot reset to its original holding position. To avoid this abnormality, the present invention adds two design features: the first feature is an inclined surface on the second transmission plate. When the circuit is open, the transmission pin mounted on the first transmission plate is tangent to the inclined surface on the second transmission plate. As the transmission pin moves upward along the inclined surface, the second transmission plate remains stationary until the transmission pin reaches the horizontal lower surface of the second transmission plate, at which point the second transmission plate begins to move. The inclined surface added to the second transmission plate provides time for the closing trip assembly to reset; the second design features a waist-shaped hole on the locking tongue. When the resetting closing trip assembly collides with the locking assembly that is being engaged, the contact force forces the locking tongue to move upward quickly along the locking tongue screw mating surface, leaving enough space for the closing trip assembly to reset. After resetting, the locking tongue moves downward under its own weight, completing the locking engagement of the closing trip assembly, preventing the circuit breaker from being closed a second time.

[0033] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A mechanical interlocking device for a circuit breaker, characterized in that: Includes side plates, top plates, output shaft assemblies, transmission modules, limit plates, interlock plates, and closing tripping assemblies; The side plate is arranged vertically and has several shaft holes. The shaft holes include an output shaft mounting hole, a first rotary shaft mounting hole, and a second rotary shaft mounting hole. Screws are also provided on the side plate. A first rotary shaft is mounted at the first rotary shaft mounting hole via a rotary bearing, and a second rotary shaft is mounted at the second rotary shaft mounting hole via a rotary bearing. The top plate is disposed on the top of the side plate perpendicular to the direction of the side plate; the top plate has a through hole for accommodating the end of the transmission module and a waist-shaped hole for the transmission plate. The output shaft assembly includes an output shaft and an outer crank arm; the output shaft is a cylindrical structure with splines and is mounted on the output shaft mounting hole of the side plate via a slewing bearing; the outer crank arm is provided with a keyway and nested on the output shaft, and a slewing pin is also provided on the outer crank arm; The transmission module includes a first transmission plate and a second transmission plate; the bottom end of the first transmission plate is connected to a rotary pin on the outer crank arm, and the first transmission plate is parallel to the side plate; a transmission pin is provided at the top end of the first transmission plate; the bottom end of the limiting plate is misaligned with the transmission pin at the top end of the first transmission plate, and a gap is left between the limiting plate and the first transmission plate; the top end of the limiting plate has a tapered section, and the outer diameter of the tapered section gradually decreases from the bottom end to the top end of the limiting plate; the top end of the limiting plate passes through the limiting plate through hole; the second transmission plate includes a crank arm section and a cylindrical section, the cylindrical section is connected to one end of the crank arm section, and the cylindrical section passes through the second transmission plate waist-shaped hole on the top plate; the crank arm section has an L-shaped structure, and the corner position of the crank arm section is fixedly connected to the first rotary shaft, the crank arm section rests on the transmission pin connecting the first transmission plate and the limiting plate, and the other end of the crank arm section is connected to the screw on the side plate through a return spring; The interlocking plate is positioned above the top plate. The side of the interlocking plate has a V-shaped groove that mates with the cylindrical section. The interlocking plate also has a guide groove that mates with the top of the limiting plate. The side of the guide groove has a notch that allows the tapered section at the end of the limiting plate to pass through completely. The maximum width of the tapered section at the top of the limiting plate is greater than the width of the guide groove of the interlocking plate, and the minimum width of the tapered section at the top of the limiting plate is less than the width of the guide groove. The closing tripping assembly includes a closing lever, a torsion spring, a closing push plate, and a locking tongue. The closing lever is mounted on a second rotating shaft via a slewing bearing, with one end of the closing lever located on the side of the first rotating shaft. The torsion spring is nested on the second rotating shaft, with one end connected to the closing lever and the other end connected to the circuit breaker. The torsion force of the torsion spring presses the closing lever against the side of the first rotating shaft. The closing push plate is bolted to the closing lever. The locking tongue is locked to the side of the first rotating shaft by a locking tongue screw and can rotate with the first rotating shaft. The locking tongue cooperates with the closing push plate to limit the closing push plate.

2. The mechanical interlocking device for a circuit breaker according to claim 1, characterized in that: The lower surface of the end of the crank arm section of the second transmission plate that connects to the return spring is provided with an inclined surface that cooperates with the transmission pin.

3. The mechanical interlocking device for a circuit breaker according to claim 1, characterized in that: The locking tongue is provided with a waist-shaped hole, and the locking tongue screw passes through the waist-shaped hole and is connected to the first rotating shaft.

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