Title of Invention

"A SHUTTER APPARATUS OF ENCLOSED SWITCHGEAR"

Abstract

[Purpose]  It is a purpose of the invention to decrease a driving force required for opening or closing a disconnecting portion, and to securely prevent the occurrence of defective opening or closing of the disconnecting portion due to an increase in friction for a long period of time. [Means for Attaining the purpose]  A shutter apparatus of the present invention is arranged so that a link which is connected with a lever at an opening portion of a shutter board for pushing up or down the shutter board is pierced through an opening of the shutter board so as to support the shutter board, and a roller is mounted on the tip of the link so as to move up and down in a guide rail, and the shutter board is also provided with rollers which move up and down on the side surfaces of the guide rail so as to operate to open or close the disconnecting portion.

Full Text

The present invention relates to a shutter apparatus of an enclosed switchgear and more particularly to a shutter apparatus for opening or closing a disconnecting portion which is connected or disconnected when an electrical apparatus such as a breaker provided in an enclosed switchgear is pushed into or pulled out. In order to make maintenance and inspection easy, a breaker housed in an enclosed switchgear is mostly arranged as a truck-type such that the breaker can be connected with or disconnected from a disconnecting portion provided on the rear surface of a housing by pushing into or pulling out the breaker from the front of the housing. In such an enclosed switchgear having the truck-type breaker, in order to prevent a charging portion of the disconnecting portion from being exposed to the outside at the time of pulling out the breaker, a shutter board which covers the front of the disconnecting portion is provided, and this shutter board operates according to the pulling-out/pushing-into operation to the breaker so as to close the disconnecting portion at the time of pulling-out and to open the disconnecting portion at the time of pushing-into. The shutter apparatus for opening and closing the shutter board in the aforementioned manner is disclosed in Japanese Patent Application Laid-Open No. 52-85342 (1977) and Japanese Patent Application Laid-Open No. 54-71345 (1979). The disconnecting portions which are opened and closed by the shutter boards are placed above and below with being separated from each other by a predetermined insulation distance. The shutter apparatus disclosed in Japanese Patent Application Laid-Open No. 52-85342 (1977) is arranged that the shutter boards, which respectively open and close the upper and lower disconnecting portions, are collected between both the disconnecting portions in the opened state. On the contrary, the shutter apparatus disclosed in Japanese Patent Application Laid-Open No. 54-71345 (1979) is arranged that the upper shutter board is pulled up and the lower shutter board is pushed down to open the respective disconnecting portions. Therefore, the latter arrangement, which can be applied to the case where the separated distance between the upper and lower disconnecting portions is short, is often adopted. Accordingly there is provided a shutter apparatus of an enclosed switchgear for opening and closing a disconnecting portion (21) which is connected/disconnected by moving of an electrical apparatus (1) by means of a shutter board (3a) which moves up and down in accordance with the moving, characterized by - guide rails (26) provided along an up-and-down moving path of the shutter board (3a); a link (4) which moves up and down by a lever (5) operated according to a position of the electric apparatus (1) which moves; - a first roller (28a) which is mounted on the tip of the link (4) which is extended into the guide rails (26) through the opening of the shutter board (3a), in contact with one of the guide rails (26) to rotate in accordance with an up-and-down movement of the shutter board (3a); and second rollers (28b) which are mounted in a portion of the shutter board (3a), in contact with one of the guide rails (26) to rotate in accordance with an up-and -down movement of the shutter board (3a). In such a shutter apparatus, a lever or link mechanism is provided for the pushing-up and pushing-down operations for the respective upper and lower shutter boards, so that when the breaker is pushed into for connection with the disconnecting portions, the shutter boards are moved by operation of the lever or link mechanism caused by contact of the lever or link mechanism with a portion of the breaker so as to open the disconnecting portions, whereas when the breaker is pulled out for disconnection from the disconnecting portions, the shutter boards are moved by operation of the lever or link mechanism caused by releasing the contact so as to close the disconnecting portions. FIGS. 1 and 2 are side views showing a typical construction of the shutter apparatus having the shutter boards which should be pushed up when opening the disconnecting portions. As shown in the drawings, a truck-type breaker 1 is mounted on a truck 10, and it is housed in a breaker housing 2 so as to be movable forward and backward (right and left in the drawings) together with the truck 10. A pair of disconnecting portions 21 and 22 are provided above and below on a rear wall 20 of the breaker housing 2 with being separated from each other by a predetermined insulation distance. When the breaker 1 in the breaker housing 2 is pushed into a connected position as shown in FIG. 1, the disconnecting portions 21 and 22 are connected with the breaker 1 by engagement with contacts 11 and 12 protruded from the rear surface of the breaker 1, and as shown in FIG. 2, the breaker 1 is pulled out to a disconnecting position so as to be disconnected from the disconnecting portions 21 and 22 by detachment of the contacts 11 and 12. A shutter holder 30 is placed in front of the upper disconnecting portion 21 along a guide pin 23 so as to be movable up and down, and a shutter board 3a is fixed to the topmost portion thereof. A lower portion of the shutter holder 30 is linked to a contact lever 5 provided on one side of a moving course of the breaker 1 by means of a connecting link 4. The contact lever 5 supports a contact piece 50 fixed to one end portion thereof by means of a supporting shaft 51 swingably, and the contact lever 5 is extended along one side of the moving course of the breaker 1 in the forward-and-backward direction, and its backward end is linked to the shutter holder 30 via the connecting link 4. A contact pin 52 is protruded at the slightly back of the supporting shaft 51 on the contact piece 50 towards the moving course of the breaker 1, and a push plate 13 is provided on the same side surface of the breaker 1 with the vertical position being adjusted with respect to the contact pin 52. In the shutter apparatus having the above construction, when the breaker 1 is in the connected position as shown in FIG. 1, the push plate 13 provided at the breaker 1 contacts with the contact pin 52 from a lower side so that the contact pin 52 is pushed up, and accordingly the contact lever 5 is slanted with its backward end upward by oscillation around the supporting shaft 51. Then, the shutter holder 30 is moved upward via the connecting link 4, and the shutter board 3a fixed to the shutter holder 30 is moved to the upper part of the breaker housing 2 so that the upper disconnecting portion 21 is opened. As shown in the drawing, the breaker 1 can be engaged with the contact 11 protruded from the backward side of the breaker 1. In the case where the breaker 1 in the above state is pulled out to the disconnected position as shown in FIG. 2, the contact of the push plate 13 whose position is changed according to this pulling-out with the contact pin 52 is released, and thus a pushing-up force is not applied to the contact pin 52. As a result, the shutter holder 30 and the shutter board 3a fixed thereto are lowered by self-weight, and thus the front of the disconnecting portion 21 is covered by it so as to be closed. Meanwhile, according to the lowering of the shutter holder 30, the contact lever 5 is oscillated around the supporting shaft 51 by the self-weight together with the connecting link 4 with its backward end downward, and the contact pin 52 is moved according to the oscillation to a position where it can contact with the push plate 13 at the time of next pushing-into of the breaker 1. However, in the shutter apparatus having the above construction, since the shutter holder 30 is moved up and down by sliding friction of the guide pin 23 and a sliding portion of a guide slot 32 of the shutter holder 30, when the breaker 1 is pushed into in a direction of the connected position, excessive driving force is required for pushing up the shutter holder 30 and the shutter board 3a, and thus smooth up-and-down operation cannot be performed. Therefore, there arises a problem such that defective opening or closing of the disconnecting portions might be occur due to increase in friction. Moreover, since the shutter board 3a is overhung to be fixed to the shutter holder 30, the shutter holder 30 is slanted by the self-weight of the shutter board 3a, the shutter board 3a cannot be maintained to be horizontal, and the friction between the shutter holder 30 and the guide pin 23 is increased. Therefore, driving force is further increased for pushing up them, there arises a problem such that smooth up-and-down operation cannot be performed. BRIEF SUMMARY OF THE INVENTION The present invention has been achieved with such points in view, and it is an object of the present invention to provide a shutter apparatus in which pushing-up/down of a shutter board which opens and closes a disconnecting portion is realized without sliding friction between a shutter holder and a guide pin, driving force required for the up-and-down operation of the shutter board is reduced, and a smooth operation can be performed for a long time. A shutter apparatus of an enclosed switchgear according to a first invention is arranged so that a link which is connected with a lever or a link mechanism linked to a position of an electrical apparatus for pushing up or down a shutter board is pierced through an opening of the shutter board so as to support the shutter board, a roller is mounted on the tip of the link in a guide rail, and rollers are provided also to the shutter board to be fitted to side surfaces of the guide rail. In the present invention, as the link which is connected with a backward end of the lever or link mechanism which moves according to the position of the electrical apparatus, is moved up and down in the guide rail, the shutter board through which the link is pierced and is supported by the link is also moved up and down on the side surfaces of the guide rails together with the link so that the disconnecting portion is opened or closed. In the shutter apparatus of enclosed switchgear according to the first invention, since the rollers are provided to the shutter board which moves up and down to open or close the disconnecting portion and to an engagement portion at the upper position of the link, rolling friction occurs on the operating portion and thus the shutter is smoothly pushed up and down. Therefore, driving force required for moving up and down the shutter board can be reduced greatly, and thus occurrence of defective opening or closing of the shutter board can be prevented. A shutter apparatus of an enclosed switchgear according to a second invention is arranged so that rollers on a shutter board on a side where a link is pierced through an opening of the shutter board so as to support the shutter board are mounted with their mounting hole pitches being displaced in a right and left direction from each other according to an inner width of a guide rail. In this invention, the upper and lower rollers on the side where the link is pierced through the shutter board contact with right and left side surfaces of the guide rail due to the right-and-left displacement of the mounting pitches and are moved up and down straight on the side surfaces of the guide rail. In the shutter apparatus of an enclosed switchgear according to the second invention, since the shutter board can be maintained horizontally and is moved up and down vertically along the inner side surfaces of the guide rails, a bending load is not applied to the link, and thus the effect which is the same as that of the first invention can be further improved. A shutter apparatus of an enclosed switchgear according to a third invention in which pulling-up is required at the time of closing a disconnecting portion is arranged that shutter boards are overlapped to be movable up and down, and the lower shutter provided with slots is hung from both lower sides of the upper shutter so that the shutters are able to move up and down. In addition, a fourth invention is arranged so that rollers are provided to sliding portions of the slots through which a pair of the upper and lower shutter boards are able to move up and down. In this invention, when the shutter boards are moved upward, the shutter boards are moved with the lower shutter being hung from the upper shutter, and they are pulled up with the overlapped portion being provided between the upper and lower shutter boards. Moreover, when the shutter boards are moved downward, the lower shutter board is stopped by a stopper or the like and the shutter boards are lowered with the upper shutter board being overlapped with the lower shutter board. In the shutter apparatus of an enclosed switchgear according to the third invention, since a pair of the shutter boards are placed that the lower shutter board is hung from the upper shutter board, it is not necessary to provide respective shutter holders, and thus the number of components can be reduced. In addition, in the shutter apparatus of an enclosed switchgear according to the fourth invention, since the rollers are provided to the sliding portions of the lower shutter, occurrence of defective return of the lower shutter can be prevented securely. The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a side view showing constitution of a conventional shutter apparatus; FIG. 2 is a side view showing constitution of the conventional shutter apparatus; FIG. 3 is a side view showing constitution of a shutter apparatus according to the present invention; FIG. 4 is a side view showing constitution of the shutter apparatus according to the present invention; FIG. 5 is a partially enlarged plan view of the shutter apparatus according to the present invention; FIG. 6 is a partially enlarged side view of the shutter apparatus according to the present invention; FIG. 7 is a front view showing the shutter apparatus according to another embodiment of the present invention; FIG. 8 is a front view showing the shutter apparatus according to further another embodiment of the present invention; FIG. 9 is a front view showing the shutter apparatus according to the further another embodiment of the present invention; and FIG. 10 is a partially enlarged plan view of the shutter apparatus according to still another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The following will describe in detail the present invention on reference to the drawings showing embodiments. FIGS. 3 and 4 are side views showing constitution of a shutter apparatus according to the present invention. In the drawing, numeral 1 denotes a breaker as a truck-type electrical apparatus, and the breaker 1 is housed in a breaker housing 2 so as to be movable forward and backward (right and left in the drawing) together with a truck 10 onto which the breaker 1 is mounted. A pair of disconnecting portions 21 and 22 are provided above and below on a rear wall 20 of the breaker housing 2 with being separated from each other by a predetermined insulation distance in a manner that their openings for connection face a forward direction. Meanwhile, contacts 11 and 12 are protruded from the rear surface of the breaker 1 in positions corresponding to the disconnecting portions 21 and 22. As shown in FIG. 3, when the breaker 1 is pushed into the breaker housing 2 up to a connected position, the disconnecting portions 21 and 22 are engaged with the respective contacts 11 and 12 to be connected. Moreover, as shown in FIG. 4, when the breaker 1 is pulled out up to a disconnected position, the contacts 11 and 12 are removed by the pulling-out so that the disconnecting portions 21 and 22 are disconnected. A pair of guide rails 26 are fixed respectively on both sides of a frame 25 in front of the upper and lower disconnecting portions 21 and 22, and as shown in FIGS. 5 and 6 (to be mentioned later), rollers 28a are provided rotatably on both sides of the point of a link 4 pierced through the shutter board 3a via a pin 27 in the guide rail 26. The link 4 and the roller 28a do not slip off forward by the pin 27 which is shorter than an inner width of the guide rail 26, and longer than an opening width of the front face of the guide rail. The lower end on the forward connecting link 4 is linked to a contact lever 5 similarly to the conventional shutter apparatus shown in FIGS. 1 and 2. Further, the contact lever 5 has a contact piece 50 on its end, and a portion of the contact piece 50 is swingably supported by an approximately horizontal supporting shaft 51 which is protruded inward from a side wall of the breaker housing 2. The contact lever 5 is extended in the forward-and-backward direction facing one side of a moving route of the breaker 1 in the vicinity of a floor of the breaker housing 2. A contact pin 52 is protruded from the contact piece 50 towards the moving route of the breaker 1 in a slightly backward position from the supporting shaft 51, and a push plate 13 is provided on the same side surface of the breaker 1 with the vertical position being adjusted with respect to the contact pin 52. In the shutter apparatus having the aforementioned arrangement, when the breaker 1 is in the connected position as shown in FIG. 3, similarly to the case of the conventional shutter apparatus shown in FIG. 1, the push plate 13 provided to the breaker 1 is brought into contact with the lower side of the contact pin 52 so as to push the contact pin 52 upward. The contact lever 5 is oscillated around the supporting shaft 51 by this pushing-up so that its backward end is slanted upward, and thus the link 4 is pushed upward so that the rollers 28a on the upper end move on the guide rail 26 while rotating. As a result, since the link 4 pierces through the opening of the shutter board 3a so as to support the shutter board 3a, the shutter board 3a operates to open or close the disconnecting portion according to the up-and-down movement of the link 4. Further, a spring 29 shown in FIGS. 3 and 4 assists pushing-up force caused by the contact of the push plate 13 with the contact pin 52, and relieves a shock when the shutter board 3a falls by its self-weight. FIGS. 5 and 6 are a partial plan view and a partially enlarged view of the shutter apparatus according to the present invention. FIG. 7 is a partially enlarged view showing another embodiment. As for upper and lower rollers 28b on the side where the link pierces through an opening on the right side to support the shutter board 3a, their mounting pitches are displaced in the right and left direction from each other by a dimension A according to the inner width of the guide rail 26 so as to keep the shutter board 3a horizontal. As for the other rollers 28b, they are placed to prevent the shutter board 3a from slipping off the guide rail 26. FIGS. 8 and 9 are partially enlarged views showing further another embodiment. As for shutter boards 3b and 3c which are arranged to be upper and lower with being overlapped and vertically removable, the lower shutter board 3c which is provided with slots are hung from both the lower sides of the upper shutter board 3b so that they are able to move up and down. FIG. 8 shows a pulled-up state when the shutter boards 3b and 3c are moved upward, and FIG. 9 shows a state that the shutter boards 3b and 3c are overlapped when they are lowered. In addition, FIG. 10 is a partially enlarged view showing still another embodiment, and a roller 28c is provided in a sliding portion of the slot of the lower shutter 3c. As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims. WE CLAIM:- 1. A shutter apparatus of an enclosed switchgear for opening and closing a disconnecting portion (21) which is connected/disconnected by moving of an electrical apparatus (1) by means of a shutter board (3a) which moves up and down in accordance with the moving, characterized by guide rails (26) provided along an up-and-down moving path of the shutter board (3a); a link (4) which moves up and down by a lever (5) operated according to a position of the electric apparatus (1) which moves; a first roller (28a) which is mounted on the tip of the link (4) which is extended into the guide rails (26) through the opening of the shutter board (3a), in contact with one of the guide rails (26) to rotate in accordance with an up-and-down movement of the shutter board (3a); and second rollers (28b) which are mounted in a portion of the shutter board (3a), in contact with one of the guide rails (26) to rotate in accordance with an up-and -down movement of the shutter board (3a). 2. The shutter apparatus of an enclosed switchgear according to claim 1, wherein the second rollers (28b) are provided on the top and bottom positions respectively on at least one of the right and left sides of the shutter board (3a), and the mounting positions of the second rollers (28b) are displaced in the width direction of the shutter board (3a) in accordance with the inner width dimension of the guide rails. 3. A shutter apparatus of an enclosed switchgear substantially as hereinbefore described with reference to the accompanying drawings.

Documents:

3439-del-1998-abstract.pdf

3439-del-1998-claims.pdf

3439-del-1998-correspondence-others.pdf

3439-del-1998-correspondence-po.pdf

3439-del-1998-description (complete).pdf

3439-del-1998-drawings.pdf

3439-del-1998-form-1.pdf

3439-del-1998-form-13.pdf

3439-del-1998-form-19.pdf

3439-del-1998-form-2.pdf

3439-del-1998-form-3.pdf

3439-del-1998-form-4.pdf

3439-del-1998-form-6.pdf

3439-del-1998-gpa.pdf

3439-del-1998-petition-137.pdf

3439-del-1998-petition-138.pdf

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