Opening / closing device for a switch rod insertion hole of a switchgear and switchgear using the same

Abstract

Opening / closing device (6) for a switching rod insertion hole (2) of a switchgear (100), comprising: an L-shaped iron sheet (3) having a vertical part through which the switching rod insertion hole (2) into which a switching rod (13) for operating a circuit breaker (15) in the switchgear (100) is to be inserted is opened and closed, the switching rod insertion hole (2) being formed in a housing of the switchgear (100); and a slide plate (4) which is engaged with a horizontal part of the L-shaped iron sheet (3) and which rotates the L-shaped iron sheet (3) by moving it up and down, wherein, when the slide plate (4) is moved upward, the L-shaped iron sheet (3) rotates to open the shift rod insertion hole (2) closed by the vertical part, and, when the slide plate (4) moves downward by its own weight, the L-shaped iron sheet (3) rotates in an opposite direction so that the vertical part of the L-shaped iron sheet (3) closes the shift rod insertion hole (2).

Description

TECHNICAL FIELDThe present disclosure relates to the field of an opening / closing device for a shift rod insertion hole of a shift rack, and a shift rack using the opening / closing device.TECHNOLOGICAL BACKGROUNDA switchgear is a power distribution apparatus in which members such as a high-voltage bus bar wire, a circuit breaker, and a breaker are integrally housed in a grounded metal case to enhance electrical safety.In a case where a contact of a circuit breaker of a switchgear is no longer to be opened and closed by an electric power due to a cause such as loss of control power for the circuit breaker, a short-circuit fault, or the like while the circuit breaker is operated, a trip button disposed at a front side of the circuit breaker needs to be operated to forcibly release the contact of the circuit breaker.However, in a case where the circuit breaker is operated, a mechanical lock mechanism acts, and therefore a front door of a circuit breaker chamber of the switchgear in which the circuit breaker is accommodated cannot be opened generally. In view of this, a switchgear housing (e.g., a front door) has a pole insertion hole, which is a small opening into which a pole for operating the trip button of the circuit breaker is to be inserted.This shift bar insertion hole of the switchgear is equipped with a shutter which is closed while the circuit breaker is normally operated. When there is a need for operating the circuit breaker through the trip bar, the trip bar insertion hole can be opened by pulling the shutter in a certain direction. When the pulling is stopped, the shutter returns to its original state due to a spring attached to the shutter to close the shift rod insertion hole. This can prevent hot gas leakage in a case where a short circuit fault or the like occurs inside the switchgear, thereby enabling high safety (see Patent Document 1).QuoteListPATENT DOCUMENTPatent Document 1: JP H09-154 208 APatent Document 2: DE 41 31 328 A1SUMMARY OF THE INVENTIONPROBLEMS TO BE SOLVED BY THE INVENTIONSuch an opening / closing device for a shift rod insertion hole of a shift apparatus undesirably requires cost for the spring itself and manufacturing cost for mounting the spring by using a spring. Further, in a case where the spring breaks due to, for example, age deterioration, the shift rod insertion hole remains opened, and therefore, hot gas generated in the switchgear due to a short circuit failure leaks to the outside and damages devices in the environment.The present disclosure has been made to solve the above problem, and an object of the present disclosure is to enable opening and closing of a shift rod insertion hole of a switchgear without a spring, thereby preventing the shift rod insertion hole from remaining open due to breakage of the spring, and preventing damage caused by leakage of hot gas.SOLUTION OF THE PROBLEMSAn opening / closing device for a pole insertion hole of a switchgear according to an aspect of the present disclosure includes: an L-shaped iron sheet having a vertical part through which the pole insertion hole into which a pole for operating a circuit breaker in the switchgear is to be inserted is opened and closed, the pole insertion hole being formed in a housing of the switchgear; and a slide plate that engages with a horizontal part of the L-shaped iron sheet and that rotates the L-shaped iron sheet by moving up and down, wherein the L-shaped iron sheet rotates, when the slide plate is moved up, to open the shift rod insertion hole closed by the vertical part, and wherein the L-shaped iron sheet rotates, when the slide plate moves down by its own weight, in a reverse direction such that the vertical part of the L-shaped iron sheet closes the shift rod insertion hole.EFFECTS OF THE INVENTIONThe opening / closing device according to an aspect of the present disclosure can open and close the shift rod insertion hole without using a spring. This can prevent the shift rod insertion hole from being kept open due to breakage of the spring, thereby preventing damage caused by leakage of hot gas.BRIEF DESCRIPTION OF THE DRAWINGS[FIG. 1 ] FIG. 1 illustrates a side cross-sectional view of a switchgear according to an embodiment.[FIG. 2 ] FIG. 2 illustrates a perspective view of a front door (front surface) having an opening / closing device according to the embodiment.[FIG. 3] FIG. 3 illustrates an enlarged perspective view of the opening / closing device of FIG. 2.[FIG. 4] FIG. 4 illustrates a perspective view of a front door (rear surface) having the opening / closing device according to the embodiment.[FIG. 5 ] FIG. 5 illustrates an enlarged perspective view of the opening / closing device of FIG. 4.DESCRIPTION OF AN EMBODIMENTIn the description of the embodiment and the drawings, parts denoted by the same reference numerals indicate the same or corresponding parts.EmbodimentThe embodiment of the present disclosure will be described below with reference to FIGS. 1 to 5.< Configuration of Switchgear>FIG. 1 illustrates a side cross-sectional view of a switchgear 100, and illustrates an arrangement of a shift rod insertion hole 2 and an opening / closing device 6 for that in the switchgear 100.First, a basic configuration of the switchgear 100 will be described with reference to FIG. 1. The left side of FIG. 1 corresponds to a front surface side of the switchgear 100, and the right side of FIG. 1 corresponds to a rear surface side of the switchgear 100. An external cable 17, a zero-phase current transformer 18, a voltmeter 19, and an ammeter 20 are disposed on the back surface side, and bus bars 16 are disposed in an intermediate part.A circuit breaker 15 is disposed on an inner side of a front door 1 of the switchgear 100, and a trip button 14 for blocking an electric current in the event of an emergency is provided on a front side of the circuit breaker 15. Further, the front door 1 has the shift rod insertion hole 2, and a shift rod 13 is inserted into this shift rod insertion hole 2. In the event of an emergency, such as a short circuit fault, the trip button 14 on the front of the circuit breaker 15 is actuated using the trip bar 13 to forcibly open a contact in the circuit breaker 15.The opening / closing device 6 for the shift rod insertion hole 2 is attached to an inner side of the front door 1 at a position corresponding to the shift rod insertion hole 2 in FIG. 1. The opening / closing device 6 used in the present embodiment of the present disclosure will be described in detail below.The present embodiment of the present disclosure discusses an example in which the shift rod insertion hole 2 into which the shift rod 13 is to be inserted from outside a housing of the switchgear 100 is formed in the front door 1 of the switchgear 100, but is not limited thereto. The shift rod insertion hole 2 may be formed in a door part of a housing covering the outside of the switchgear 100, or may be formed in any other parts.<Konfiguration of Ratchet Rod Insertion Hole Opening / Closing Device>FIGS. 2 to 5 each illustrate the opening / closing device 6 for the shift rod insertion hole 2 formed in the front door 1 of the shift apparatus 100. FIG. 2 illustrates a front side of the front door 1, FIG. 4 illustrates a state seen from a rear side of the front door 1, and FIGS. 3 and 5 illustrate enlarged views of opening / closing device parts in FIGS. 2 and 4, respectively.As illustrated in FIG. 2, the shift rod insertion hole 2 is formed in a nearly central part of the front door 1, and the opening / closing device 6 is disposed at a rear of the front door 1. In the enlarged view illustrated in FIG. 3, the opening / closing device 6 is seen through the front door 1, which is therefore indicated by dashed lines. A handle 5 for operating the opening / closing device 6 protrudes from the rear side toward the front side of the front door 1, and is therefore indicated by solid lines.Although the front door 1 itself is not illustrated in FIG. 3, a handle draw-out hole 9 formed in the front door 1 through which the handle 5 protrudes from the front door 1 and the shift rod insertion hole 2 formed in the front door 1 are indicated by solid lines for explaining the opening / closing device 6.FIG. 5 illustrates an enlarged view of the opening / closing device 6 provided at the rear of the front door 1 illustrated in FIG. 4, and the opening / closing device 6 is provided between a support plate 10 and the front door 1 (not illustrated as in FIG. 3 ).It is understood from FIGS. 2 to 5, particularly from FIGS. 3 and 5, that the opening / closing device 6 is mainly constituted by an L-shaped iron plate 3 (iron plate) which constitutes a shutter for opening and closing the shift rod insertion hole 2 and a slide plate 4 which is connected to the L-shaped iron plate 3 and which allows the L-shaped iron plate 3 to rotate.The L-shaped iron sheet 3 is constituted by a vertical part of the L-shape (hereinafter referred to as a vertical part) serving as a shutter for closing the shift rod insertion hole 2 and a horizontal part of the L-shape (hereinafter referred to as a horizontal part) connected to the slide plate 4. The L-shaped iron sheet 3 is configured to rotate about a rotation axis inserted into a through hole formed in a bent part of the L-shape of the L-shaped iron sheet 3.The handle 5 is fixed to one surface of the slide plate 4 using a rivet as illustrated in FIG. 3. A pin 12 corresponding to a guide hole 11 formed in the retainer plate 10 is provided on the other surface of the slide plate 4.Of arrows shown in FIGS. 3 and 5, a curved arrow 7 indicates a rotation direction in which the L-shaped iron sheet 3 moves, and a straight arrow 8 indicates an up-down direction in which the slide plate 4 moves. As illustrated in FIGS. 3 and 5, the L-shaped iron sheet 3 is disposed to rotate about the rotation axis penetrating the bent part of the L-shape, and the slide plate 4 is disposed to move in the up-down direction while being guided by a protrusion provided on the holding plate 10 that holds the slide plate 4.<Operation of Ratchet Rod Insertion Hole Opening / Closing Device>An operation of the opening / closing device 6 for the shift rod insertion hole 2 of the switchgear 100 will be mainly described with reference to FIGS. 3 and 5. FIGS. 3 and 5 each illustrate a state in which the shift rod insertion hole 2 is closed, and the shift rod insertion hole 2 is closed by the vertical part of the L-shaped iron sheet 3.The horizontal part of the L-shaped iron sheet 3 forms a connecting structure by engaging with the slide plate 4. The horizontal part of the L-shaped iron sheet 3 also moves in the up-down direction in accordance with movement of the slide plate 4 in the up-down direction, and as a result, the L-shaped iron sheet 3 rotates in the direction indicated by the curved arrow 7 in FIGS. 3 and 5.That is, when a need arises for operating the release button 14 of the circuit breaker 15 of the switchgear 100, the handle 5 protruding from the front door 1 is moved upward. This causes the slide plate 4 to move upward in the up-down direction indicated by the straight arrow 8 in FIGS. 3 and 5, thereby causing the horizontal part of the L-shaped iron sheet 3 connected to the slide plate 4 to also move upward.As a result, the L-shaped iron sheet 3 rotates clockwise as viewed from the front side, the vertical part of the L-shaped iron sheet 3 closing the shift rod insertion hole 2 moves to open the shift rod insertion hole 2, and thus the trip button 14 of the circuit breaker 15 can be operated.It is to be noted that a distance over which the slide plate 4 is movable in the up-down direction can be varied by adjusting the size of the handle draw-out hole 9 formed for operating the handle 5 from the front door 1 and the length of the guide hole 11 formed in the support plate 10 as a guide for the pin attached to the slide plate 4. As a result, an angle through which the L-shaped iron sheet 3 rotates can be adjusted.When the shift rod 13 is pulled out from the shift rod insertion hole 2 after operation of the trigger 14, the slide plate 4 moves downward by a weight of the slide plate 4 and the handle 5 when the handle 5 or the like is not held. At the same time, the L-shaped iron plate 3 connected to the slide plate 4 rotates in an opposite direction, i.e., counterclockwise as viewed from the front side, so that the shift rod insertion hole 2 is closed by the vertical part of the L-shaped iron plate 3.As described above, in the embodiment of the present disclosure, the shift rod insertion hole 2 is closed by the weights of the links such as the slide plate 4 after operation of the trigger 14. This can prevent an operation failure from occurring, for example, can prevent the shift rod insertion hole 2 from being left open, thereby preventing damage to surrounding devices caused by leakage of hot gas generated inside the switchgear 100 due to, for example, a short circuit in the circuit breaker 15.Further, component cost can be kept low as compared with a conventional opening / closing device that closes the shift rod insertion hole 2 using a spring or the like, and the opening / closing device 6 is inexpensive and safe because leakage of hot gas that may occur due to deterioration of the spring or the like does not occur.Although the disclosure is described above with respect to an exemplary embodiment and implementation, it should be understood that the various features, aspects, and functionality described in the embodiment are not limited in applicability to the particular embodiment in which they are described, but instead may be applied to other embodiments alone or in various combinations.It is therefore to be understood that numerous modifications that have not been provided with examples may be devised without departing from the scope of the present disclosure. For example, at least one constituent component could be modified, added, or eliminated. At least one of the constituent components mentioned in the preferred embodiment could be selected and combined with the constituent components in another preferred embodiment.DESCRIPTION OF THE REFERENCE NUMERALS1 Front door 2 Pole insertion hole 3 L-shaped iron sheet 4 Slide plate 5 Handle 6 Opening / closing device 7 Curved arrow 8 Straight arrow 9 Handle extraction hole 10 Holding plate 11 Guide hole 12 Pin 13 Pole 14 Release button 15 Circuit breaker 16 Bus bar 17 External cable 18 Zero-phase current transformer 19 Voltmeter 20 Ammeter 100 Switchgear

Claims

An opening / closing device (6) for a pole insertion hole (2) of a switchgear (100), comprising: an L-shaped iron sheet (3) having a vertical part through which the pole insertion hole (2) into which a pole (13) for operating a circuit breaker (15) in the switchgear (100) is to be inserted is opened and closed, wherein the pole insertion hole (2) is formed in a housing of the switchgear (100); and a slide plate (4) which is engaged with a horizontal part of the L-shaped iron sheet (3) and which rotates the L-shaped iron sheet (3) by moving up and down, wherein when the slide plate (4) is moved up, the L-shaped iron sheet (3) rotates to open the shift rod insertion hole (2) closed by the vertical part, and when the slide plate (4) moves down by its own weight, the L-shaped iron sheet (3) rotates in an opposite direction so that the vertical part of the L-shaped iron sheet (3) closes the shift rod insertion hole (2).The opening / closing device (6) according to claim 1, wherein the weight of the slide plate (4) is larger than a weight of the L-shaped iron sheet (3).Switchgear (100) comprising the opening / closing device (6) according to claim 1 or 2.

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