JP5913719B1 - Short-circuit prevention cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a short-circuit prevention cover which is easy to use with an inexpensive and simple structure and does not become unusable because a part thereof is lost. SOLUTION: A rectangular plate-like body 1 having three vertically long rectangular openings and six permanent magnets 7 embedded in an upper edge surface 6 of the plate-like body 1 are provided. 4 is vertically long, the central rectangular opening 3 has the same width as the terminal portion, and the widths of the left and right rectangular openings 2 and 4 are set to be considerably larger than the width of the central rectangular opening 3. Further, the plate-like body 1 is provided with a concave portion 5 for facilitating holding, and a string 9 for facilitating removal of the plate-like body 1 after work is attached to the corner. [Selection] Figure 1

Description

  The present invention relates to a short-circuit prevention cover for preventing a short-circuit accident in a terminal block such as a watt-hour meter.

Low-voltage electric meters such as watt-hour meters are installed in homes and business offices, and constantly measure the power supplied through the service lines from the outside.
In addition, since the low-voltage electric meter is used for calculating the electricity rate, it is required to accurately measure the amount of electric power, and is exchanged for a new product or a maintenance product that has been certified at regular intervals.
This replacement is performed by removing all the wires connected to the power supply side terminal and load side terminal of the low-voltage electric meter, but usually the replacement work is performed with the power supply side and load side wires kept in a live state. It has been broken.
Therefore, when removing the wire by loosening the terminal screw that presses the tip of the wire on the power supply side and load side terminal, the tip of the tool such as a driver held by the operator slips to the terminal screw of another adjacent wire. Contact may cause a short circuit accident.

Therefore, as described in Patent Document 1 (Japanese Patent No. 4549791), a strip-shaped transparent plate having at least one working opening having a size corresponding to one of a plurality of terminal portions, A low voltage electric meter having a holder having guide means for slidably guiding a transparent plate body along the row of terminal portions and a mounting means for mounting the holder at a predetermined position on the outer surface of the low voltage electric meter Short-circuit prevention devices are known.
Further, Patent Document 2 (Japanese Patent No. 3043753) discloses an electrical insulation in which a plurality of working holes are formed which are detachably attached to a connecting portion of a watt hour meter having a plurality of terminals and open to face each terminal. There is described a working cover device for a watt-hour meter provided with a flexible connecting portion cover body and holding means for holding the connecting portion cover body in the connecting portion.

Japanese Patent No. 4549791 Japanese Patent No. 3043753

However, the short-circuit prevention device for low-voltage electric meters described in Patent Document 1 includes a transparent plate having a working opening, a holder having guide means for slidably guiding the transparent plate, and the It is equipped with mounting means for mounting the holding tool at a predetermined position of the low-voltage electric meter, and it is necessary to accurately match the dimensions of the transparent plate and the guide means in addition to the complicated structure. Problems, such as the need to use an expensive resin with a low coefficient of thermal expansion, such as polycarbonate, problems that the components that make up the short-circuit prevention device fall apart, and it takes time to assemble or some parts are lost there were.
In addition, the work cover device for the watt-hour meter described in Patent Document 2 includes a screw hole and a screw in which holding means for holding the connection portion cover body on the connection portion is provided on both side walls of the connection portion cover body. Since the structure is complicated and the screw part has to be rotated when it is held in the connection part, there are problems of high price, poor workability, and unusable if the screw part is lost There was a problem of becoming.
The object of the present invention is to solve such a problem and to be easy to use with a simple structure, to be manufactured from various materials, and to be inexpensive and prevent short-circuiting from being lost. Is to provide.

The invention according to claim 1 is a short-circuit prevention cover for preventing a short-circuit accident in a terminal block in which a plurality of terminal portions are installed in a row, and three rectangular openings are arranged side by side at a predetermined interval. and there insulating plate body, in the vicinity of the upper edge or the lower edge of the plate-like body, provided with a permanent magnet for temporarily holding the plate-like body in front of the terminal block, said three central rectangular opening of the rectangular opening has the same width as one of the previous SL pin portion, the width of the other of the rectangular opening than 1.2 times the width of the rectangular opening of the central It is large.

  The invention according to claim 2 is the short-circuit prevention cover according to claim 1, wherein the upper or lower edge of the plate-like body has a flat portion, and one or more permanent magnets are installed in the flat portion. It is characterized by being.

  The invention according to claim 3 is the short-circuit prevention cover according to claim 1, wherein the upper edge portion or the lower edge portion of the plate-like body has a flat surface portion, and a protrusion is provided along the flat surface portion. One or a plurality of the permanent magnets are installed on the protrusion.

According to the first aspect of the present invention, the permanent magnet is provided in the vicinity of the upper edge or the lower edge of the plate-like body. The plate-like body can be temporarily held on the front surface of the terminal block so that the desired terminal portion is located within the central rectangular opening simply by attracting the permanent magnet to a certain location.
The central rectangular opening has the same width and the end terminal part, the width of the other of the rectangular opening is greater than 1.2 times the width of the central rectangular opening of the three rectangular openings Therefore, when used in various watt hour meters and the like where the distance between the terminal portion and the terminal portion is different, if the plate-like body is held so that the desired terminal portion is located within the central rectangular opening, There is an effect that a terminal portion adjacent to the terminal portion can easily be accommodated in another rectangular opening.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the upper edge or the lower edge of the plate-like body has a flat portion, and the permanent magnet is installed on the flat portion. Because the permanent magnets are attracted to the lower surface of the metallic housing at the top of the terminal block or the upper surface of the metallic housing at the lower portion of the terminal block, the plate-like body is temporarily placed on the front surface of the terminal block. Can be held.
Further, regardless of which side of the plate-like body is the front side, the permanent magnet can be adsorbed on the lower surface of the metallic casing at the upper part of the terminal block or the upper surface of the metallic casing at the lower part of the terminal block. So workability is excellent.
Furthermore, when a plurality of permanent magnets are installed, the magnetic flux density of the permanent magnets can be suppressed, so that the influence of the lines of magnetic force from the permanent magnets on the instrument can be reduced.

According to the invention according to claim 3, in addition to the effect of the invention according to claim 1, the upper edge or the lower edge of the plate-like body has a flat surface portion, and the ridge portion extends along the flat surface portion. Since the permanent magnet is provided on the protruding portion, the permanent magnet is permanently attached to the upper or lower surface of the metallic casing at the upper portion of the terminal block or the lower or upper surface of the metallic casing at the lower portion of the terminal block. By attracting the magnet, the plate-like body can be temporarily held on the front surface of the terminal block.
Therefore, it is possible to hold the plate-like body against various types of terminal blocks.
In addition, when a plurality of permanent magnets are installed, the magnetic flux density of the permanent magnets can be suppressed, so that the influence of the lines of magnetic force from the permanent magnets on the instrument can be reduced.

FIG. 3 is a perspective view of a short-circuit prevention cover according to the first embodiment. FIG. 3 is a front view of the short-circuit prevention cover according to the first embodiment. The rear view of the short circuit prevention cover of Example 1. FIG. FIG. 3 is a plan view of the short-circuit prevention cover according to the first embodiment. FIG. 3 is a bottom view of the short-circuit prevention cover according to the first embodiment. The side view of the short circuit prevention cover of Example 1. FIG. The figure which shows the state which attached the short circuit prevention cover of Example 1 to the watt-hour meter. The perspective view of the short circuit prevention cover of Example 2. FIG. The figure which shows the state which attached the short circuit prevention cover of Example 2 to the watt-hour meter.

  Hereinafter, embodiments of the present invention will be described by way of examples.

A perspective view, a plan view, a bottom view, a front view, a rear view, and a side view of the short-circuit prevention cover of Example 1 are shown in FIGS. 1 to 6, and a perspective view in a state where the short-circuit prevention cover is attached to the watt hour meter. As shown in FIG.
As shown in FIGS. 1 and 2, the short-circuit prevention cover of Example 1 is provided with three vertically long rectangular openings 2 to 4 and a recess 5 in a plate 1 made of an insulating opaque white resin, As shown in FIGS. 1 and 4, six permanent magnets 7 are embedded in the upper edge surface 6 at equal intervals, and as shown in FIG. 1, a hole 8 is made in the lower left corner, and a string is placed in the hole 8. 9 is an annular shape.
As the insulating opaque white resin constituting the plate-like body 1, polyacetal that is inexpensive and easy to mold is suitable.

The plate-like body 1 is rectangular and has a width of 110 mm, a length of 39 mm, a thickness of 3 mm, and the concave portion 5 provided on the left side of the surface of the plate-like body 1 is a semicircular shape with a vertically long shape of 15 mm wide, 30 mm long, 30 mm long The hole 8 provided in the left corner of 1 is circular and has a diameter of 2 mm, and the string 9 has a length of 20 cm.
Further, the rectangular openings 2 to 4 are arranged with an interval of 4 mm in the right direction from the center of the plate-like body 1, and both are 23 mm in length and the lower side is located 3 mm above the lower edge of the plate-like body 1.
The central rectangular opening 3 is 9 mm wide and the left and right rectangular openings 2 and 4 are 14 mm wide. The horizontal width of the central rectangular opening 3 is substantially the same as the horizontal width of the terminal portions 11 to 13. The lateral widths of the rectangular openings 2 and 4 are set to be considerably larger than the lateral widths of the terminal portions 11 to 13.

The six permanent magnets 7 for holding the plate 1 on the front surface of the terminal block 10 are cylindrical neodymium magnets having a diameter of 3 mm and a length of 4 mm, and an area of about 1 cm to 8 cm from the right end of the upper edge surface 6. Embedded at substantially equal intervals, and the surface thereof is substantially flush with the upper edge surface 6.
Although the surface magnetic flux density of the cylindrical neodymium magnet was 400 mT, it was confirmed that the measurement result of the watt hour meter would not be affected if the magnetic flux density was about this level.

The procedure for using the short-circuit prevention cover of Example 1 when replacing the watt-hour meter is as follows.
(1) Remove the cover (not shown) attached to the front surface of the terminal block 10 of the watt-hour meter to perform the replacement work, and expose the terminal portions 11 to 13 and the like (usually the left side power supply side terminal and the right side terminal Three terminal portions are installed on each load side terminal).
(2) Hold the plate-like body 1 with both hands, and adjust the left and right positions so that the central terminal portion 12 installed on the load side terminal is accommodated in the central rectangular opening 3.
If the left thumb belly is positioned in the recess 5, the plate-like body 1 can be firmly grasped, so that the position can be easily adjusted.
(3) The upper edge surface 6 of the plate-like body 1 is brought close to the lower surface 14 of the upper housing of the watt-hour meter, and the upper edge surface 6 is attracted to the lower surface 14 of the upper housing by the magnetic force of the permanent magnet 7 and both hands are released ( The state of FIG.
(4) Loosen the terminal screw 15 of the terminal portion installed on the load side terminal and remove the electric wire 16.
(5) The string 9 is pulled, the upper edge surface 6 is separated from the lower surface 14 of the upper housing, and the plate-like body 1 is removed.

(6) Hold the plate-like body 1 with both hands and adjust the left and right positions so that the central terminal portion (not shown) installed on the power supply side terminal fits in the central rectangular opening 3.
(7) The upper edge surface 6 of the plate-like body 1 is brought close to the lower surface 14 of the upper housing of the watt hour meter, and the upper edge surface 6 is attracted to the lower surface 14 of the upper housing by the magnetic force of the permanent magnet 7 and both hands are released.
(8) Loosen the terminal screw (not shown) of the terminal portion installed on the power supply side terminal and remove the electric wire 16.
(9) The string 9 is pulled, and the upper edge surface 6 is separated from the lower surface 14 of the upper housing to remove the plate-like body 1.

(10) Remove the old watt hour meter and install a new watt hour meter.
(11) Remove the cover (not shown) attached to the front of the terminal block of the new watt hour meter to expose the terminal part.
(12) Hold the plate-like body 1 with both hands and adjust the left and right positions so that the central terminal portion (not shown) installed on the power supply side terminal is accommodated in the central rectangular opening 3.
(13) The upper edge surface 6 of the plate-like body 1 is brought close to the lower surface 14 of the upper housing of the watt hour meter, and the upper edge surface 6 is attracted to the lower surface 14 of the upper housing by the magnetic force of the permanent magnet 7 and both hands are released.
(14) After loosening the terminal screw (not shown) of the terminal portion installed on the power supply side terminal and inserting the electric wire 16, the terminal screw is tightened to fix the electric wire 16.
(15) Pulling the string 9, the upper edge surface 6 is separated from the lower surface 14 of the upper housing, and the plate-like body 1 is removed.

(16) Hold the plate-like body 1 with both hands and adjust the left and right positions so that the central terminal portion 12 installed on the load side terminal is accommodated in the central rectangular opening 3.
(17) The upper edge surface 6 of the plate-like body 1 is brought close to the lower surface 14 of the upper housing of the watt hour meter, and the upper edge surface 6 is attracted to the lower surface 14 of the upper housing by the magnetic force of the permanent magnet 7 and both hands are released.
(18) After loosening the terminal screw 15 of the terminal portion installed on the load side terminal and inserting the electric wire, the terminal screw 15 is tightened to fix the electric wire 16 (state of FIG. 7).
(19) The string 9 is pulled, and the upper edge surface 6 is separated from the lower surface 14 of the upper housing to remove the plate-like body 1.
(20) A cover is attached to the front surface of the terminal block 10 of the new watt hour meter.

  The main purpose of the short-circuit prevention cover is to prevent the driver etc. of the operator from coming into contact with the terminal screws of other adjacent wires, but it also has the effect of making it easier to work because the work location can be limited, The effect is higher when an opaque short-circuit prevention cover is used.

A perspective view of the short-circuit prevention cover of Example 2 is shown in FIG. 8, and a perspective view of the state in which the short-circuit prevention cover is attached to the watt hour meter is shown in FIG.
As shown in FIG. 8, the short-circuit prevention cover of Example 2 is provided with three vertically long rectangular openings 2 to 4 and a concave portion 5 in a plate-like body 21 made of opaque white resin, and along its lower edge portion 22. The ridges 23 are provided, and six permanent magnets 7 are embedded at equal intervals from the upper surface side of the ridges 23, a hole 24 is formed in the upper left corner thereof, and the hole 24 is annularly formed through the string 9. Is.
The short-circuit prevention cover of Example 2 is provided with a protrusion 23 along the lower edge portion 22 of the short-circuit prevention cover, and the point that the permanent magnet 7 is embedded on the upper surface side of the protrusion 23, and a plate-like body The second embodiment is different from the first embodiment in that a hole 24 is formed in the upper left corner of 21.
Therefore, the same reference numerals are given to the same components as those in the first embodiment in FIGS. 8 and 9, and descriptions of materials and dimensions are omitted.

The ridge 23 provided along the lower edge 22 has a length of 110 mm, a length of 5 mm, and a thickness of 3 mm, and is molded integrally with the plate-like body 21.
Six permanent magnets 7 are embedded in an area of about 1 cm to 8 cm from the right end of the ridge 23 at substantially equal intervals, and the surface thereof is substantially flush with the upper surface of the ridge 23.
The hole 24 has a circular shape with a diameter of 2 mm, similar to the hole 8 of the first embodiment.

  The procedure for using the short-circuit prevention cover of Example 2 when replacing the watt-hour meter is substantially the same as the procedure for using the short-circuit prevention cover of Example 1, but the plate-like body 1 becomes the plate-like body 21. And in steps (3), (7), (13), and (17), the upper edge surface 6 of the plate-like body 1 is brought close to the lower surface 14 of the upper housing of the watt-hour meter, and the upper edge is obtained by the magnetic force of the permanent magnet 7. Instead of attracting the surface 6 to the lower surface 14 of the upper housing, the lower edge portion 22 of the plate-like body 21 is brought closer to the lower surface 25 of the lower housing of the watt-hour meter, and the ridge portion 23 is generated by the magnetic force of the permanent magnet 7. In the steps (5), (9), (15), and (19), instead of separating the upper edge surface 6 from the lower surface 14 of the upper housing, the ridges are attracted to the lower surface 25 of the lower housing. The difference is that the upper surface of the portion 23 is separated from the lower surface 25 of the lower housing.

The modification of Example 1 and 2 is listed.
(1) The dimensions and shapes of the plate-like body 1, the rectangular openings 2 to 4, the concave portion 5, the permanent magnet 7, the hole 8, and the string 9 shown in the first embodiment are examples, and power that may be used. Needless to say, it can be changed to a size and shape suitable for a quantity meter or the like, or can be changed to a size and shape considering usability and design.
In the first embodiment, the lateral widths of the left and right rectangular openings 2 and 4 are 1.56 times the lateral width of the central rectangular opening 3, but the watt-hour meter that may be used. 1.2 times or more is sufficient when it can be limited, and even 1.5 times or more is sufficient even for various watt-hour meters that are often used at present.
The lateral width of the central rectangular opening 3 is 9 mm, and the three rectangular openings are arranged with an interval of 4 mm. The lateral width is the lateral width of the terminal portion of the watt hour meter or the like that may be used. Is determined according to the one having the largest interval, and the interval is determined according to the one having the smallest interval between the terminal portions among watt-hour meters and the like that may be used.

(2) In Examples 1 and 2, the plate-like bodies 1 and 21 are made of an opaque white resin, but may be transparent or a color other than white. Any material such as manufactured can be used.
Moreover, when preparing the multiple types of short circuit prevention cover from which a dimension and a shape differ, you may change the color given to the plate-shaped objects 1 and 21 for every kind.
(3) In Examples 1 and 2, the recess 5, holes 8, 24, and string 9 are provided, but these hold the plate-like bodies 1 and 21 temporarily on the front surface of the terminal block, and the terminal screws Since it is not an essential configuration for preventing a short-circuit accident when turning, it may not be provided.
(4) In Examples 1 and 2, three rectangular openings 2 to 4 were provided, but when two rectangular openings were provided and there were three terminal parts, the work was performed on two terminal parts. Thereafter, the work may be performed on the remaining one terminal portion by shifting the positions of the plate-like bodies 1 and 21.

(5) In the first and second embodiments, six cylindrical neodymium magnets are used as the permanent magnets 7. However, any kind of magnet may be used, and the number is not limited to six and may be one or more than six. good.
However, if the magnetic flux density is high, the instrument may be affected. Therefore, when reducing the number of magnets, it is better to use a long and narrow magnetic flux to reduce the magnetic flux density.
(6) In the first embodiment, the permanent magnet 7 is embedded in the upper edge surface 6, and in the second embodiment, the permanent magnet 7 is embedded in the upper surface side of the protrusion 23, but in the first embodiment, the permanent magnet 7 is embedded in the upper edge surface 6. Instead of or in addition, it may be provided on the lower edge surface, and in Example 2, it may be provided on the upper edge surface 6 in addition to the upper surface side of the ridge 23.
In the second embodiment, the ridge portion 23 is provided along the lower edge portion 22. However, the ridge portion is provided along the upper edge portion, and the permanent magnet 7 is provided on the lower surface side of the ridge portion. May be.
(7) Although the permanent magnet 7 is embedded in the upper edge surface 6 in the first embodiment, if there is a metal member including a vertical surface at the upper or lower portion of the terminal block, the permanent magnet 7 is either the upper edge or the lower edge. It may be provided on the back surface side in the vicinity of the portion, or may be provided on both the upper edge surface 6 or the lower edge surface and the back surface side in the vicinity of the upper edge portion or the lower edge portion.
(8) In Example 2, the ridge 23 is formed by molding integrally with the plate-like body 21, but it may be formed separately and bonded to the back side of the lower edge.

DESCRIPTION OF SYMBOLS 1 Plate-like body 2-4 Rectangular opening 5 Recessed part 6 Upper edge surface 7 Permanent magnet 8 Hole 9 String 10 Terminal block 11-13 Terminal part 14 Lower surface of upper housing | casing 15 Terminal screw 16 Electric wire 21 Plate-like body 22 Lower edge part 23 ridge part 24 hole 25 lower surface of lower housing

Claims (3)

A short-circuit prevention cover for preventing a short-circuit accident in a terminal block in which a plurality of terminal portions are installed in a row ,
An insulating plate-like body provided with three rectangular openings arranged at a predetermined interval ;
In the vicinity of the upper edge or the lower edge of the plate-like body, provided with a permanent magnet for temporarily holding the plate-like body on the front surface of the terminal block,
Has a central rectangular opening equivalent width as one of the previous SL pin portion among the three rectangular apertures, 1 the width of the other rectangular opening having a width of the rectangular opening of the central .Short-circuit prevention cover characterized by being larger than 2 times. The upper or lower edge of the plate-like body has a flat portion,
The short-circuit prevention cover according to claim 1, wherein one or a plurality of the permanent magnets are installed on the planar portion. The upper or lower edge of the plate-like body has a flat portion,
A ridge is provided along the plane portion,
The short-circuit prevention cover according to claim 1, wherein one or a plurality of the permanent magnets are installed on the protrusion.

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