Earth unit

Abstract

To provide an earth unit capable of flexibly responding to an increase or decrease in the number of load devices, and eliminating the need for work such as re-installing earth bars, even if the number of load devices increases significantly.SOLUTION: By inserting plug blade parts 19, 19 of one terminal unit 2 into a base 6 through insertion ports 12A and 12B of another terminal unit 2 and clamping them between blade support spring parts 18, 18, the terminal units 2, 2 are connected to each other, and bar metal fittings 7A, 7A and bar metal fittings 7B, 7B are electrically connected to each other, forming two earth bars. Therefore, the overall length of the earth bar can be adjusted by changing the number of connected terminal units 2, 2...SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an earth unit that is installed in, for example, a distribution board to ground a load device. [Background technology]

[0002] Conventionally, an earth unit for grounding load equipment has been devised, for example, as described in Patent Document 1. That is, an earth bar is installed inside a distribution board, and a terminal unit is appropriately attached to the earth bar, the terminal unit having an electric wire fixing portion for connecting an earth wire extending from the load equipment side and a connection portion that can be connected to the earth bar. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-103317 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the earthing unit described in Patent Document 1 has the problem that it cannot flexibly accommodate an increase or decrease in the number of load devices. For example, if the number of load devices increases beyond the initial estimate, the length of the earthing bar will be insufficient, and a situation will arise in which the earthing bar will have to be reinstalled.

[0005] Therefore, the present invention has been made in consideration of the above problems, and aims to provide an earthing unit that can flexibly respond to increases or decreases in the number of load devices, and does not require work such as re-installing the earthing bar, even if the number of load devices increases significantly. [Means for solving the problem]

[0006] In order to achieve the above object, the invention described in claim 1 of the present invention is an earth unit formed by connecting a plurality of terminal units, each having an earth bar fitting built into a base, in a predetermined direction, wherein each of the terminal units is provided with a connecting protrusion that protrudes in the predetermined direction and a connecting portion into which the connecting protrusion can be inserted, and the terminal units are connected to each other by inserting the connecting protrusion into the connecting portion, and as the terminal units are connected to each other, the earth bar fittings are brought into electrical conduction to form an earth bar, while the length of the earth bar can be adjusted by changing the number of terminal units to be connected. The invention of claim 2 is characterized in that, in the invention of claim 1, the earth bar fittings are provided with blades protruding from the base in the predetermined direction as the connecting protrusions, and blade receiving springs capable of clamping the blades are provided as the connected parts, and further, insertion ports into which the blades can be inserted are provided at locations on the base corresponding to the blade receiving springs, and by inserting the blades of one of the terminal units into the base through the insertion port of the other terminal unit and clamping it between the blade receiving springs, the terminal units are connected to each other and the earth bar fittings are electrically connected to each other to form an earth bar. The invention described in claim 3 is the invention described in claim 1, wherein the earth bar fitting is provided with a leaf spring-like abutment piece that protrudes from the base in the predetermined direction and has elasticity in the predetermined direction, and an abutted portion that can be abutted by the abutment piece; An exposure window for exposing the abutted portion is provided at a location on the base corresponding to the abutted portion, and when the terminal units are connected to each other by inserting the connecting protrusion into the connected portion, the abutting piece of one terminal unit abuts against the abutted portion of the other terminal unit in a pressed state, and the earth bar fittings are connected to each other to form an earth bar. [Effects of the Invention]

[0007] According to the present invention, each terminal unit is provided with a connecting protrusion that protrudes in a predetermined direction and a connecting portion into which the connecting protrusion can be inserted. The terminal units are connected to each other by inserting the connecting protrusion into the connecting portion. Furthermore, as the terminal units are connected to each other, the earth bar fittings are electrically connected to each other to form an earth bar. The length of the earth bar can be adjusted by changing the number of connected terminal units. This allows for flexible response to increases or decreases in the number of load devices, and even if the number of load devices increases significantly, there is no need to reposition the earth bar. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective explanatory view showing an earth unit in which a ground-side earth wire and a load-side earth wire are connected; FIG. [Figure 2] FIG. 10 is an explanatory perspective view showing the earth unit disassembled into a plurality of terminal units and a terminal base unit. [Figure 3] FIG. 2 is a perspective explanatory view showing the terminal unit in an exploded state. [Figure 4] FIG. 10 is a perspective explanatory view showing the terminal base unit in a disassembled state. [Figure 5] 10 is an explanatory diagram showing a horizontal cross section of the leftmost terminal base unit and the second terminal units from the left in the earth unit. FIG. [Figure 6] 10 is an explanatory diagram showing a vertical cross section of a state in which a first wire insertion hole is opened by a switching lever and a load-side earth wire is inserted through the first wire insertion hole. FIG. [Figure 7] 10 is an explanatory diagram showing a vertical cross section of a state in which a second wire insertion hole is opened by a switching lever and a load-side earth wire is inserted through the second wire insertion hole. FIG. [Figure 8] 8 is an explanatory diagram showing a state in which the switching lever is being operated to remove the load-side earth wire from the state shown in FIG. 7. FIG. [Figure 9] FIG. 4 is an explanatory diagram showing a vertical cross section of the terminal base unit. [Figure 10]FIG. 10 is an explanatory perspective view showing a modified example of an earth unit in which a ground-side earth wire and a load-side earth wire are connected. [Figure 11] FIG. 10 is an explanatory perspective view showing a modified example of the earth unit disassembled into a plurality of terminal units and a terminal base unit. [Figure 12] 1A is a perspective explanatory view showing the front, left side, and top of the terminal unit, and FIG. 1B is a perspective explanatory view showing the front, right side, and top of the terminal unit. [Figure 13] FIG. 2 is a perspective explanatory view showing the terminal unit in an exploded state. [Figure 14] 1A is a perspective explanatory view showing the front, left side, and top of the terminal base unit, and FIG. 1B is a perspective explanatory view showing the front, right side, and top of the terminal base unit. [Figure 15] FIG. 10 is a perspective explanatory view showing the terminal base unit in a disassembled state. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A ground unit according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0010] FIG. 1 is an explanatory perspective view showing an earthing unit 1 to which ground-side earth wires 50, 50 and load-side earth wires 51, 51·· are connected. FIG. 2 is an explanatory perspective view showing the earthing unit 1 disassembled into multiple terminal units 2, 2·· and terminal base units 3, 3. FIG. 3 is an explanatory perspective view showing the terminal unit 2 in the disassembled state. FIG. 4 is an explanatory perspective view showing the terminal base unit 3 in the disassembled state. FIG. 5 is an explanatory view showing a horizontal cross section of the leftmost terminal base unit 3 and the second-to-left terminal units 2, 2 in the earthing unit 1. FIG. 6 is an explanatory view showing a vertical cross section in which the first wire insertion hole 25A is opened by the switching lever 8 and the load-side earth wire 51 is inserted through the first wire insertion hole 25A. FIG. 7 is an explanatory view showing a vertical cross section in which the second wire insertion hole 25B is opened by the switching lever 8 and the load-side earth wire 51 is inserted through the second wire insertion hole 25B. Fig. 8 is an explanatory diagram showing a state in which the switching lever 8 is being operated to remove the load-side earth wire 51 from the state shown in Fig. 7. Fig. 9 is an explanatory diagram showing a vertical cross section of the terminal base unit 3.

[0011] The earthing unit 1 is used to ground a load device (not shown) and comprises a terminal unit assembly in which a plurality of terminal units 2, 2... are connected in a row as described below, and terminal base units 3, 3 connected to both ends of the terminal unit assembly. This earthing unit 1 is installed, for example, in a distribution board, and enables grounding of the load device by connecting load-side earth wires 51, 51... extending from the load device side to the terminal units 2, 2... and ground-side earth wires 50, 50 extending to the ground side to the terminal base unit 3, respectively.

[0012] First, the terminal unit 2 will be described. The terminal unit 2 comprises a base 6, bar fittings 7A, 7B and a switching lever 8 mounted within the base 6, and a cover body 9 attached to cover the top surface of the base 6. The base 6 is a block body made of synthetic resin molded into a substantially cubic shape, with a first accommodating recess 10A for accommodating the bar fitting 7A provided at the front of the base 6 and a second accommodating recess 10B for accommodating the bar fitting 7B provided at the rear of the base 6. The first accommodating recess 10A and the second accommodating recess 10B open to the top surface of the base 6 and are separated into the front and rear of the base 6 by an insulating wall 13. Furthermore, two front and rear notches 11A and 11B are provided on the left side surface of base 6, cutting downward from the upper edge to approximately the same depth as both accommodating recesses 10A and 10B, with front notch 11A communicating with first accommodating recess 10A and rear notch 11B communicating with second accommodating recess 10B. Meanwhile, two front and rear sockets 12A and 12B are provided on the right side surface of base 6, with front socket 12A communicating with the internal space of first accommodating recess 10A and rear socket 12B communicating with the internal space of second accommodating recess 10B. The distance between sockets 12A and 12B in the front-to-rear direction is the same as the distance between notches 11A and 11B in the front-to-rear direction. In addition, screw holes 14 for fastening the cover body 9 with fixing screws 26 are drilled in the upper surface of the base 6, particularly in the upper surface of the insulating wall 13 portion.

[0013] The bar fitting 7A is formed by integrating an electric wire clamping fitting 15, which is formed by bending a strip-shaped metal plate into a roughly U-shape in side view, and an earth bar fitting 16, which is a metal plate whose thickness is in the front-to-rear direction and is arranged so as to penetrate the electric wire clamping fitting 15 in the left-to-right direction. Both longitudinal ends of the electric wire clamping fittings 15, which face each other from the front to the rear, are provided with portions bent in directions that bring them closer to each other, and these bent portions function as electric wire clamping portions 17 that clamp, from the front and rear, the load-side earth wire 51 inserted into the electric wire clamping fitting 15 from above. Meanwhile, the end of the earth bar fitting 16 protruding to the right from the electric wire clamping fitting 15 is formed in a bifurcated shape, and this bifurcated portion serves as a blade receiving spring portion 18 that has a function similar to that of a blade receiving spring that clamps the plug blades of a plug in an outlet device. Furthermore, the portion of the earth bar fitting 16 that protrudes leftward from the wire clamping fitting 15 protrudes leftward beyond the base 6 via the cutout portion 11A when housed in the first housing recess 10A of the bar fitting 7A, and serves as a blade portion 19 that has the same function as the blades of a plug. Note that, like the bar fitting 7A, the bar fitting 7B is formed by integrating the wire clamping fitting 15 having the wire clamping portion 17 with the earth bar fitting 16 having the blade receiving spring portion 18 and the blade portion 19.

[0014] The switching lever 8 comprises a strip-shaped cover portion 20 extending in the front-to-rear direction and a knob portion 21 protruding upward from the top surface of the cover portion 20, and the cover portion 20 is arranged to be slidable in the front-to-rear direction on the base 6, and in particular to be slidable in the front-to-rear direction on the electric wire clamping portions 17 of the bar fittings 7A, 7B arranged in both accommodating recesses 10A, 10B. In addition, the cover portion 20 is provided at both the front and rear ends with claw portions 22 protruding downward and notches 23 for avoiding interference with the load-side earth wire 51 inserted into the accommodating recesses 10A, 10B.

[0015] Meanwhile, cover body 9 is provided with an operation hole 24 through which knob 21 can pass and which guides the movement of knob 21 as switching lever 8 moves forward and backward. A first wire insertion hole 25A is provided in front of operation hole 24 for inserting load-side earth wire 51 into first accommodating recess 10A. A second wire insertion hole 25B is provided behind operation hole 24 for inserting load-side earth wire 51 into second accommodating recess 10B. In addition, fixing holes 47 are drilled at locations corresponding to screw holes 14 for fastening cover body 9 to the top surface of base 6 with fixing screws 26.

[0016] The terminal unit 2 as described above is assembled by accommodating the bar fittings 7A, 7B in both accommodating recesses 10A, 10B of the base 6, then arranging the switching lever 8 in a position on the top surface of the base 6 above the wire clamping portions 17, 17, and finally screwing the cover body 9 to the top surface of the base 6 while causing the knob portion 21 of the switching lever 8 to protrude upward through the operation hole 24. In this assembled state, the blade portions 19, 19 of the bar fittings 7A, 7B protrude leftward beyond the base 6 through the notches 11A, 11B. Furthermore, the blade receiving spring portions 18, 18 of the bar fittings 7A, 7B are located to the left of the insertion port 12A in the first accommodating recess 10A and to the left of the insertion port 12B in the second accommodating recess 10B. Therefore, when the two terminal units 2, 2 are lined up side by side and the blade portions 19, 19 of the right terminal unit 2 are inserted into both accommodating recesses 10A, 10B through the insertion openings 12A, 12B of the left terminal unit 2, the blade portions 19, 19 of the right terminal unit 2 are clamped by the blade receiving spring portions 18, 18 of the left terminal unit 2, and electrical continuity is established between the bar fittings 7A of the right terminal unit 2 and the bar fittings 7A of the left terminal unit 2, and between the bar fittings 7B of the right terminal unit 2 and the bar fittings 7B of the left terminal unit 2. Note that the bar fittings 7A and 7B are insulated from each other.

[0017] 6, when the knob 21 is positioned toward the rear end within the operation hole 24, the cover 20 closes the wire insertion hole 25B, leaving only the wire insertion hole 25A open, allowing only the load ground wire 51 to be inserted into the first accommodating recess 10A. Conversely, when the knob 21 is positioned toward the front end within the operation hole 24, the cover 20 closes the wire insertion hole 25A, leaving only the wire insertion hole 25B open, allowing only the load ground wire 51 to be inserted into the second accommodating recess 10B. When the load ground wire 51 is inserted into the first accommodating recess 10A through the wire insertion hole 25A, the load ground wire 51 is clamped by the wire clamping portion 17 of the bar fitting 7A, establishing electrical continuity between the load ground wire 51 and the bar fitting 7A. Furthermore, when the load side earth wire 51 is inserted into the second accommodating recess 10B through the wire insertion hole 25B, the load side earth wire 51 is clamped by the wire clamping portion 17 of the bar fitting 7B, and the load side earth wire 51 and the bar fitting 7B are brought into an electrically conductive state.

[0018] When removing the load-side earth wire 51, the switch lever 8 is operated in a direction away from the load-side earth wire 51 (toward the edge nearest the operation hole 24). For example, when the load-side earth wire 51 is inserted in the second accommodating recess 10B as shown in Fig. 7, the switch lever 8 is operated forward. Then, as shown in Fig. 8, the rear claws 22 interfere with the wire clamping portions 17 of the bar fitting 7B, pushing the wire clamping portions 17 apart, making it possible to remove the load-side earth wire 51 from the second accommodating recess 10B.

[0019] Next, the terminal base unit 3 will be described. The terminal base unit 3 includes a base 27, nuts 28A, 28B and terminal seat fittings 29A, 29B attached to the base 27, and terminal screws 30A, 30B for electrically connecting ground wires 50, 50 to the terminal seat fittings 29A, 29B. The base 27 is a block body made of synthetic resin and molded into a substantially rectangular parallelepiped shape that is long in the front-to-rear direction, with a first terminal base mounting portion 31A provided at the front of the base 27 and a second terminal base mounting portion 31B provided at the rear of the base 27. The terminal base mounting portions 31A, 31B are separated into front and rear portions by an insulating wall 32 that stands upright in the center of the top surface of the base 27 in the front-to-rear direction. Furthermore, each terminal base mounting portion 31A, 31B has flat portions 33A, 33B that become approximately flat when nuts 28A, 28B are fitted into them, and metal fitting accommodating recesses 34A, 34B that are recessed downward from the surfaces of flat portions 33A, 33B at the edge of insulating wall 32 and can accommodate part of terminal metal fittings 29A, 29B. Reference numeral 44 denotes an attachment hole for fastening terminal metal fittings 29A, 29B to terminal base mounting portions 31A, 31B with attachment screws 43.

[0020] Two front and rear connecting pieces 35, 35 protruding leftward are provided on the left side surface of the base 27. Each connecting piece 35 is shaped similarly to the blade portions 19 of the terminal unit 2, and the distance between the two connecting pieces 35 in the front-to-rear direction is the same as the distance between the blade portions 19 of the terminal unit 2 in the front-to-rear direction. Furthermore, two front and rear sockets 36A, 36B are provided on the right side surface of the base 27, with the front socket 36A communicating with the internal space of the front metal fitting accommodating recess 34A and the rear socket 36B communicating with the internal space of the rear metal fitting accommodating recess 34B. The distance between the sockets 36A and 36B in the front-to-rear direction is the same as the distance between the blade portions 19 of the terminal unit 2 in the front-to-rear direction. In addition, installation pieces 37, 37 having installation holes for installing the terminal base unit 3, and therefore the earth unit 1, in a distribution board or the like are provided on the bottom of the base 27 and protrude in the left and right directions.

[0021] The terminal washer 29A is formed by bending downward the rear portion of a strip-shaped metal plate extending in the front-to-rear direction. The strip-shaped portion extending in the front-to-rear direction forms a connection portion 38 to which the ground wire 50 is connected, and the portion extending downward forms a fixing portion 39 to which a blade receiving spring fitting 40 is fixed. The blade receiving spring fitting 40 functions similarly to the blade receiving spring portion 18 of the terminal unit 2 and is fixed to the front surface of the fixing portion 39 in a position that allows connection to the blade 19 of the terminal unit 2 from the right side. The fixing portion 39 and the blade receiving spring fitting 40 can be accommodated within the fitting accommodating recess 34A. When the fixing portion 39 and the blade receiving spring fitting 40 are accommodated within the fitting accommodating recess 34A, the connection portion 38 rests on the flat portion 33A. A terminal hole 41 is provided at the location corresponding to the nut 28A for threading the terminal screw 30A into the base 27 via the nut 28A. Furthermore, the connection portion 38 is provided with a round hole 42 for fastening the terminal washer 29A to the terminal seat mounting portion 31A with a mounting screw 43. The terminal washer 29B is formed by bending downward the front portion of a strip-shaped metal plate extending in the front-to-rear direction, and like the terminal washer 29A, the strip-shaped portion extending in the front-to-rear direction is the connection portion 38, and the portion extending downward is the fixing portion 39. A blade receiving spring fitting 40 is fixed to the rear surface of the fixing portion 39 in a position that allows connection to the blade portion 19 of the terminal unit 2 from the right side.

[0022] When assembling the terminal base unit 3 described above, first, nuts 28A, 28B are fitted into terminal base mounting portions 31A, 31B, respectively, to form flat portions 33A, 33B, and then, as shown in Fig. 9, the fixing portion 39 and blade receiving spring fitting 40 of terminal washer 29A are accommodated in fitting accommodating recess 34A, and the fixing portion 39 and blade receiving spring fitting 40 of terminal washer 29B are accommodated in fitting accommodating recess 34B, respectively, and connecting portions 38, 38 are placed on flat portions 33A, 33B. Next, mounting screws 43, 43 are screwed in to attach terminal washer 29A, 29B to terminal base mounting portions 31A, 31B, and assembly of terminal base unit 3 is completed. In the terminal base unit 3 assembled in this manner, the blade receiving spring fittings 40 of the terminal seat fittings 29A, 29B are located to the left of the insertion opening 36A in the fitting accommodating recess 34A and to the left of the insertion opening 36B in the fitting accommodating recess 34B. When the terminal unit 2 is placed on the right side of the terminal base unit 3 and the blade portions 19 of the terminal unit 2 are inserted into the fitting accommodating recesses 34A, 34B through the insertion openings 36A, 36B of the terminal base unit 3, the blade portions 19 are clamped between the blade receiving spring fittings 40, establishing electrical continuity between the bar fitting 7A of the terminal unit 2 and the terminal seat fitting 29A of the terminal base unit 3, and between the bar fitting 7B of the terminal unit 2 and the terminal seat fitting 29B of the terminal base unit 3. Furthermore, when the ground-side earth wire 50 is screwed to the connection portion 38 of the terminal seat metal 29A using the terminal screw 30A, the ground-side earth wire 50 is connected to the terminal seat metal 29A, and when the ground-side earth wire 50 is screwed to the connection portion 38 of the terminal seat metal 29B using the terminal screw 30B, the ground-side earth wire 50 is connected to the terminal seat metal 29B. The terminal seat metal 29A and the terminal seat metal 29B are insulated from each other.

[0023] On the other hand, when the terminal base unit 3 is disposed on the right side of the terminal unit 2 and the connecting pieces 35, 35 of the terminal base unit 3 are inserted into the accommodating recesses 10A, 10B through the insertion openings 12A, 12B of the terminal unit 2, the connecting pieces 35, 35 are clamped by the blade receiving spring portions 18, 18, connecting the terminal unit 2 and the terminal base unit 3. In this connected state, the bar fittings 7A, 7B inside the terminal unit 2 are not electrically connected to the terminal base unit 3, so there is no need to attach nuts 28A, 28B, terminal seat fittings 29A, 29B, terminal screws 30A, 30B, etc. to the terminal base unit 3 connected in this way.

[0024] Here, a description will be given of how to use the earth unit 1 formed by connecting the terminal unit 2 and the terminal base unit 3. First, a desired number of terminal units 2, 2... are connected together by inserting blades 19, 19 into sockets 12A, 12B to form a terminal unit assembly. In this usage mode, the blades 19, 19 at the left end of the terminal unit assembly are inserted into sockets 36A, 36B from the right side of terminal base unit 3, which has terminal seats 29A, 29B attached. Meanwhile, the connecting pieces 35, 35 of terminal base unit 3, which does not have terminal seats 29A, 29B attached, are inserted into sockets 12A, 12B from the right side of the terminal unit assembly to form grounding unit 1. The grounding unit is then installed in a distribution board or the like by fastening the installation pieces 37, 37 with screws. Ground wires 50 are then connected to terminal seats 29A, 29B of the leftmost terminal base unit 3, respectively. This results in two electrically independent grounding bars at the front and rear of grounding unit 1. That is, a first earth bar is formed from the terminal seat metal fitting 29A and the bar metal fittings 7A, 7A··, and a second earth bar is formed from the terminal seat metal fitting 29B and the bar metal fittings 7B, 7B··.

[0025] Therefore, in this usage mode, the first earth bar is used as an earth bar for type D grounding of load equipment not connected to an electric circuit protected by an earth leakage breaker, and the second earth bar is used as an earth bar for grounding of load equipment connected to an electric circuit protected by an earth leakage breaker, i.e., so-called ELB grounding. That is, when performing type D grounding of the load equipment, the switch lever 8 is slid rearward and the load-side earth wire 51 is inserted into the base 6 through the wire insertion hole 25A, so that the load-side earth wire 51 is connected to the first earth bar. On the other hand, when performing ELB grounding of the load equipment, the switch lever 8 is slid forward and the load-side earth wire 51 is inserted into the base 6 through the wire insertion hole 25B, so that the load-side earth wire 51 is connected to the second earth bar. Therefore, the switching lever 8 can be operated depending on the type of load equipment to which the load side earth wire 51 is connected to the terminal unit 2, and the appropriate earth bar to which it is connected can be selected.In the example shown in Figure 1, the load side earth wires 51 connected to the third and fourth terminal units 2 from the left are connected to the first earth bar, and the load side earth wires 51 connected to the first, second, and fifth terminal units 2 from the left are connected to the second earth bar.

[0026] Furthermore, when the number of load devices to be grounded increases, simply remove the right-most terminal base unit 3, add the required number of terminal units 2 to the terminal unit assembly, and then reconnect the terminal base unit 3 to the right end. Increasing the number of terminal units 2 in this way results in a longer overall length of the earth bar. Conversely, when the number of load devices to be grounded decreases, simply reduce the number of terminal units 2 in the terminal unit assembly. That is, simply remove the terminal units 2 that are no longer needed. Reducing the number of terminal units 2 in this way results in a shorter overall length of the earth bar. It is possible to reverse the installation orientation of the earth unit 1 in a distribution board, etc., so that the terminal base metal fittings 29A, 29B, etc. appear to be attached to the right-most terminal base unit 3. Furthermore, if a large number of terminal units 2 are required and the earth unit 1, especially the terminal unit assembly, becomes too long, there is no problem with installing multiple earth units 1 in a single distribution board.

[0027] According to the earthing unit 1 configured as described above, the bar fittings 7A, 7B each include an earth bar fitting 16 having blades 19 protruding in a predetermined direction from the base 6 and blade receiving springs 18 that can clamp the blades 19. The base 6 also includes sockets 12A, 12B into which the blades 19 can be inserted, located at positions corresponding to the blade receiving springs 18. The blades 19 of one terminal unit 2 are inserted into the base 6 through the sockets 12A, 12B of the other terminal unit 2 and clamped between the blade receiving springs 18, thereby connecting the terminal units 2 and forming two earth bars by electrically connecting the bar fittings 7A, 7A together and the bar fittings 7B, 7B together. Therefore, the overall length of the earth bar can be adjusted by changing the number of connected terminal units 2. Therefore, an increase or decrease in the number of load devices can be flexibly accommodated simply by increasing or decreasing the number of terminal units 2, 2..., and even if the number of load devices increases significantly, work such as re-installing the earth bar is not required, making it possible to create an earth unit 1. Furthermore, since the terminal units 2, 2 can be connected to each other by utilizing a configuration that provides conductivity between bar fittings 7A, 7A and between bar fittings 7B, 7B, the structure can be streamlined.

[0028] Each terminal unit 2 is provided with two wire insertion holes 25A, 25B into which the load side earth wire 51 can be inserted, and is also provided with a switching lever 8 that can slide back and forth, and by operating the switching lever 8, it is possible to open only one of the two wire insertion holes 25A, 25B and close the other wire insertion holes. In other words, by operating the switching lever 8, it is possible to close the wire insertion holes that do not correspond to the bar fitting to be wired, and therefore to the earth bar, so there is no risk of erroneously connecting the load side earth wire 51 to an earth bar other than the earth bar to which it should be connected, and erroneous connection of the load side earth wire 51 can be effectively prevented.

[0029] Furthermore, in a configuration in which multiple terminal units 2, 2... are connected, the earth bar to which the load side earth wire 51 is connected can be selected by operating the switching lever 8 for each terminal unit 2, thereby making it possible to extremely effectively prevent incorrect wiring of the load side earth wire 51.

[0030] Next, a modified example of the grounding unit according to the present invention will be described, which is a grounding unit 61 that differs from the above embodiment in the structure relating to the connection between the terminal units 62, 62, and the connection between the terminal unit 62 and the terminal base unit 63.

[0031] FIG. 10 is a perspective view of an earth unit 61 to which ground-side earth wires 50 and load-side earth wires 51 are connected. FIG. 11 is a perspective view of the earth unit 61 disassembled into a plurality of terminal units 62 and terminal base units 63. FIG. 12(a) is a perspective view of the front, left side, and top of the terminal unit 62, and FIG. 12(b) is a perspective view of the front, right side, and top of the terminal unit 62. FIG. 13 is a perspective view of the disassembled terminal unit 62. FIG. 14(a) is a perspective view of the front, left side, and top of the terminal base unit 63, and FIG. 14(b) is a perspective view of the front, right side, and top of the terminal base unit 63. FIG. 15 is a perspective view of the disassembled terminal base unit 63. 10 to 15, the same components as those in the above embodiment are denoted by the same reference numerals.

[0032] The earth unit 61 is used to ground the load equipment in the same way as the earth unit 1, and comprises a terminal unit assembly in which a plurality of terminal units 62, 62... are connected in a row, and terminal base units 63, 63 connected to both ends of the terminal unit assembly. The load side earth wires 51, 51... are connected to the terminal units 62, 62..., and the ground side earth wires 50, 50 are connected to the terminal base unit 63, thereby enabling the load equipment to be grounded.

[0033] The terminal unit 62 differs significantly from the terminal unit 2 in the configuration of the base 64 and the bar fittings 65A and 65B mounted within the base 64. The base 64 is formed in the shape of a rectangular box made of synthetic resin, and a first accommodating recess 66A is provided in the front portion of the base 64 to accommodate the bar fitting 65A and a front connecting claw 69A of the terminal unit 62 or terminal base unit 63 located on the right side of the base 62 when connected as described below. The first accommodating recess 66A has a fitting accommodating section that accommodates the bar fitting 65A and a claw accommodating section that is recessed forward from the fitting accommodating section in the front wall that stands up to close the front side of the fitting accommodating section and accommodates the connecting claw 69A when connected. In addition, a second accommodating recess 66B is provided in the rear portion of the base 64 to accommodate the bar fitting 65B and a rear connecting claw 69B of the terminal unit 62 or terminal base unit 63 located on the right side of the base 64 when connected as described below. The second accommodating recess 66B has a metal fitting accommodating section that accommodates the bar metal fitting 65B, and a claw accommodating section that is recessed rearward from the metal fitting accommodating section in a rear wall that stands up to close the rear side of the metal fitting accommodating section and that accommodates a connecting claw 69B when connected. The first accommodating recess 66A and the second accommodating recess 66B are separated from the front and rear of the base 64 by an insulating wall 13. Two front and rear connecting windows 68A and 68B are opened on the left side surface of the base 64, with the front connecting window 68A communicating with the metal fitting accommodating section of the first accommodating recess 66A and the rear connecting window 68B communicating with the metal fitting accommodating section of the second accommodating recess 66B. Furthermore, connecting claws 69A and 69B that protrude leftward are provided on the front and rear outer sides of the connecting windows 68A and 68B on the left side surface of the base 64.

[0034] Meanwhile, two exposure windows 70A, 70B are formed on the right side of the base 64, one at the front and one at the back. The front exposure window 70A communicates with the metal fitting accommodating portion of the first accommodating recess 66A, and the rear exposure window 70B communicates with the metal fitting accommodating portion of the second accommodating recess 66B. Furthermore, connecting openings 71A, 71B, into which the connecting claws 69A, 69B can be inserted, are formed on the front and rear outer sides of the exposure windows 70A, 70B on the right side of the base 64. The front connecting opening 71A communicates with the claw accommodating portion of the first accommodating recess 66A, and the rear connecting opening 71B communicates with the claw accommodating portion of the second accommodating recess 66B. Furthermore, locking openings 72 are formed on both the front and rear sides of the base 64. These locking openings communicate with the corresponding claw accommodating portions, and allow the connecting claws 69A, 69B inserted into the claw accommodating portions to be locked. Screw holes 14 are provided on the top surface of the base 64, so that the cover body 9 can be screwed in the same way as the terminal unit 2. The cover body 9 is also provided with an operation hole 24 through which the knob portion 21 of the switching lever 8, which is disposed so as to straddle the bar fittings 65A and 65B, is inserted, and wire insertion holes 25A and 25B for inserting the load-side earth wire 51.

[0035] The bar fitting 65A is formed by integrating an electric wire clamp fitting 15, which is configured similarly to that employed in the bar fitting 7A, with an earth bar fitting 73, which is a metal plate whose thickness is in the up-down direction and is arranged so as to penetrate the electric wire clamp fitting 15 in the left-right direction. The end of the earth bar fitting 73, which protrudes to the right from the electric wire clamp fitting 15, is bent so as to stand up. When the bar fitting 65A is accommodated in the first accommodating recess 66A, this standing portion is exposed within the exposure window 70A and functions as an abutted portion 74 against which an abutting piece 75, described below, can abut when the terminal units 62, 62 are connected to each other. In addition, the end of the earth bar fitting 73, which protrudes to the left from the electric wire clamp fitting 15, is bent up and formed like a leaf spring that is elastic in the left-right direction. When the bar fitting 65A is accommodated in the first accommodating recess 66A, this leaf spring-like portion protrudes leftward beyond the base 64 through the connecting window 68A, and functions as an abutting piece 75 that abuts against the abutted portion 74 of the bar fitting 65A located adjacent to it on the left when the terminal units 62, 62 are connected to each other. Note that, like the bar fitting 65A, the bar fitting 65B is formed by integrating the electric wire clamp fitting 15 and the earth bar fitting 73 having the abutted portion 74 and the abutting piece 75.

[0036] The terminal unit 62 as described above is assembled by accommodating the bar fittings 65A, 65B in both accommodating recesses 66A, 66B of the base 64, then arranging the switching lever 8 in a position on the top surface of the base 64 above the wire clamping portions 17, 17, and finally screwing the cover body 9 to the top surface of the base 64 while causing the knob portion 21 of the switching lever 8 to protrude upward through the operation hole 24. In this assembled state, the abutment pieces 75, 75 of the bar fittings 65A, 65B protrude leftward beyond the base 64 through the connecting windows 68A, 68B. Furthermore, the abutted portions 74, 74 of the bar fittings 65A, 65B are located to the left of the exposure window 70A in the first accommodating recess 66A and to the left of the exposure window 70B in the second accommodating recess 66B. When the two terminal units 62 are lined up side by side and the connecting claws 69A, 69B of the right terminal unit 62 are inserted into the accommodating recesses 66A, 66B through the connecting openings 71A, 71B of the left terminal unit 62, the connecting claws 69A, 69B engage with the locking openings 72, 72, and the terminal units 62 are connected to each other. In addition, in this connected state, the abutting pieces 75, 75 of the right terminal unit 62 abut against the abutted portions 74, 74 of the left terminal unit 62 in a pressed state, and the bar fitting 65A of the right terminal unit 62 and the bar fitting 65A of the left terminal unit 62 are electrically connected, and the bar fitting 65B of the right terminal unit 62 and the bar fitting 65B of the left terminal unit 62 are also electrically connected.

[0037] On the other hand, terminal base unit 63 differs significantly from terminal base unit 3 in the configuration of base 76 and terminal seats 77A, 77B mounted within base 76. Base 76 is a synthetic resin block molded into a generally rectangular parallelepiped shape that is long in the front-to-rear direction. A first terminal base mounting portion 78A is provided at the front of base 76, and a second terminal base mounting portion 78B is provided at the rear of base 76. Both terminal base mounting portions 78A, 78B are separated into front and rear sections by insulating wall 32 that stands upright in the center of the top surface of base 76 in the front-to-rear direction. Furthermore, the flat upper surface of each terminal base mounting portion 78A, 78B is provided with terminal screw holes 80 for screwing terminal screws 30A, 30B into base 76, and mounting holes 44 for screwing terminal seats 77A, 77B to terminal base mounting portions 78A, 78B with mounting screws 43. Furthermore, two front and rear connecting claws 69A, 69B similar to those of the terminal unit 62 are provided on the left side surface of the base 76 to protrude leftward. In addition, two front and rear connecting holes 79A, 79B are provided on the right side surface of the base 76, into which the connecting claws 69A, 69B of the terminal unit 62 located adjacent to the left can be inserted and into which the inserted connecting claws 69A, 69B can be locked.

[0038] Terminal washer 77A is a metal plate that is roughly T-shaped in top view and integrally includes a strip-shaped portion extending in the front-to-rear direction, a left arm portion protruding leftward from the rear end of the strip-shaped portion, and a right arm portion protruding rightward from the rear end of the strip-shaped portion. The strip-shaped portion extending in the front-to-rear direction serves as connection portion 38 to which ground wire 50 is connected, just like terminal washer 29A. Connection portion 38 has terminal hole 41 for threading terminal screw 30A into base 76 and round hole 42 for fastening terminal washer 77A to terminal washer mounting portion 78A with mounting screw 43. The right arm portion protruding rightward is bent downward approximately vertically to function as abutted piece 81 against which abutting piece 75 can abut when connecting to terminal unit 62. Furthermore, the left arm protruding to the left is bent in a curved shape that bulges forward and extends downward, and functions as a pressing piece 82 that can come into pressing contact with the abutment portion 74 when connected to the terminal unit 62. Terminal washer 77B is provided with a left arm and a right arm that protrude in the left and right directions from the front end of a band-shaped portion that extends in the front-to-rear direction, and like terminal washer 77A, the right arm is formed as the abutment piece 81 and the left arm is formed as the pressing piece 82.

[0039] To assemble the terminal base unit 63 as described above, the terminal base mounting portions 78A, 78B are each fitted with the contact piece 81 and the pressing piece 82 so that they face the insulating wall 32, with the contact piece 81 positioned on the right side of the base 76 and the pressing piece 82 positioned on the left side of the base 76, and then the terminal washers 77A, 77B are then fastened with the mounting screws 43, 43. By fastening the terminal washers 77A, 77B with the screws in this manner, the contact pieces 81, 81 of the terminal washers 77A, 77B are positioned on the rear side of the base 76 between the connecting holes 79A, 79B and the extension of the insulating wall 32, with the front faces of the contact pieces 81, 81 abutting against the rear face of the base 76. In addition, the pressing pieces 82, 82 of both terminal seat fittings 77A, 77B are located on the front side of the base 76 between the connecting claws 69A, 69b and the portion on the extension line of the insulating wall 32, and the rear surfaces of the pressing pieces 82, 82 protrude forward beyond the front surface of the base 76.

[0040] Therefore, when terminal unit 62 is arranged to the right of terminal base unit 63 and connecting claws 69A, 69B of terminal unit 62 are inserted into connecting holes 79A, 79B of terminal base unit 63, connecting claws 69A, 69B engage with base 76 within connecting holes 79A, 79B, connecting terminal base unit 63 and terminal unit 62. In addition, in this connected state, abutting pieces 75, 75 of terminal unit 62 abut against abutted pieces 81, 81 of terminal base unit 63 in a pressing state, establishing electrical continuity between bar metal fitting 65A of terminal unit 62 and terminal base metal fitting 77A of terminal base unit 63, and between bar metal fitting 65B of terminal unit 62 and terminal base metal fitting 77B of terminal base unit 63. Furthermore, when the ground-side earth wire 50 is screwed to the connection portion 38 of the terminal seat metal 77A using the terminal screw 30A, the ground-side earth wire 50 is connected to the terminal seat metal 77A, and when the ground-side earth wire 50 is screwed to the connection portion 38 of the terminal seat metal 77B using the terminal screw 30B, the ground-side earth wire 50 is connected to the terminal seat metal 77B. The terminal seat metal 77A and the terminal seat metal 77B are insulated from each other.

[0041] On the other hand, when the terminal base unit 63 is disposed on the right side of the terminal unit 62 and the connecting claws 69A, 69B of the terminal base unit 63 are inserted into the connecting openings 71A, 71B of the terminal unit 62, the connecting claws 69A, 69B are engaged with the locking openings 72, 72, connecting the terminal unit 62 and the terminal base unit 63. In addition, in this connected state, the pressing pieces 82, 82 of the terminal base unit 63 come into pressing contact with the abutted portions 74, 74 of the terminal units 62, 62, establishing electrical continuity between the bar fitting 65A of the terminal unit 62 and the terminal base fitting 77A of the terminal base unit 63, and between the bar fitting 65B of the terminal unit 62 and the terminal base fitting 77B of the terminal base unit 63. If the ground-side earth wire 50 is not connected to the terminal base unit 63, there is no need to attach the terminal base fittings 77A and 77B to the base 76, whether the terminal base unit 63 is arranged on the right or left side of the terminal unit 62. That is, for example, in the case shown in Figures 10 and 11, there is no problem even if the terminal base fittings 77A and 77B attached to the right-side terminal base unit 63 are removed.

[0042] To assemble the grounding unit 61, first connect the desired number of terminal units 62, 62... by inserting and locking the connecting claws 69A, 69B into the connecting holes 71A, 71B. Next, from the right side of the terminal base unit 63 to which the terminal washers 77A, 77B, etc. are attached, the connecting claws 69A, 69B at the left end of the terminal unit assembly are inserted into the connecting holes 79A, 79B and locked. Meanwhile, from the right side of the terminal unit assembly, the connecting claws 69A, 69B of another terminal base unit 63 are inserted into the connecting holes 71A, 71B and locked. The grounding unit 61 assembled in this manner has two electrically independent grounding bars at the front and rear. That is, a first grounding bar is formed by the terminal washers 77A and the bar fittings 65A, 65A..., and a second grounding bar is formed by the terminal washers 77B and the bar fittings 65B, 65B....

[0043] According to the earth unit 61 having the above-described configuration, the base 64 of the terminal unit 62 is provided with connecting claws 69A, 69B that protrude in a predetermined direction, as well as connecting ports 71A, 71B into which the connecting claws 69A, 69B can be inserted, and locking ports 72, 72 into which the connecting claws 69A, 69B inserted into the connecting ports 71A, 71B can be locked. By inserting the connecting claws 69A, 69B into the connecting ports 71A, 71B and locking them into the locking ports 72, 72, the terminal units 62, 62 can be linked together. Furthermore, the bar fittings 65A, 65B are each provided with a leaf-spring-like abutment piece 75 that protrudes in a predetermined direction from the base 64 and is elastic in the predetermined direction, and abutted portions 74 against which the abutment piece 75 can abut, and exposure windows 70A, 70B for exposing the abutted portions 74, 74 are provided at locations on the base 64 that correspond to the abutted portions 74, 74. When the terminal units 62, 62 are connected together using the connecting claws 69A, 69B, the abutment pieces 75, 75 of one terminal unit 62 abut against the abutted portions 74, 74 of the other terminal unit 62 in a pressed state, and the bar fittings 65A, 65A and the bar fittings 65B, 65B are each electrically connected, thereby forming two earth bars. Therefore, similar to the earth unit 1 of the above embodiment, the overall length of the earth bar can be adjusted by changing the number of terminal units 62, 62... to be connected, and the earth unit 61 can be made to be flexibly responsive to an increase or decrease in the number of load devices simply by increasing or decreasing the number of terminal units 62, 62....

[0044] The earthing unit of the present invention is not limited to the above-described embodiments and modified examples, and the overall configuration of the terminal unit and terminal base unit can be appropriately modified as necessary within the scope of the present invention.

[0045] For example, in the above embodiment and modified example, two earth bars are formed by connecting the terminal units together, but only one earth bar may be formed. In other words, the configuration in which two bar fittings are installed inside the base of the terminal unit may be changed to one in which only one bar fitting is installed. In such a case, a switching lever or the like is of course not required, and only one wire insertion hole for inserting the load side earth wire is required.

[0046] Furthermore, in the above embodiment, a switching lever that slides in the forward and backward directions is used as the switching means, but it is also possible to provide a switching means that switches the wire insertion hole that opens by rotating it around an axis in the up and down direction, or a switching means that switches the wire insertion hole that opens by tilting it in the forward and backward directions around an axis in the left and right direction, and the specific structure of the switching means can be designed and modified as appropriate. Furthermore, the specific configuration for connecting multiple terminal units together, such as the position, number, and shape of the connecting claws, can be modified as appropriate, and it is also possible to adopt a structure for connecting by inserting a plug into an outlet as in the above embodiment, and also configure it to have the connecting claws, etc., described in the modified example. [Explanation of symbols]

[0047] 1··Earth unit, 2··Terminal unit, 6··Base, 7A, 7B··Bar fittings (earth bars), 12A, 12B··Socket port, 15··Wire clamping fitting, 16··Earth bar fittings (earth bars), 18··Blade receiving spring part (connected part), 19··Plug blade part (connecting protrusion), 61··Earth unit, 62··Terminal unit, 64··Base, 65A, 65B··Bar fittings (earth bars), 69A, 69B··Connecting claws (connecting protrusion), 70A, 70B··Exposure window, 71A, 71B··Connecting port (connected part), 72··Latching port (connected part), 73··Earth bar fittings (earth bars), 74··Abutting part, 75··Abutting piece.

Claims

1. An earth unit is formed by connecting a plurality of terminal units, each having an earth bar metal fitting built into a base, in a predetermined direction, Each of the terminal units is provided with a connecting protrusion that protrudes in the predetermined direction and a connected portion into which the connecting protrusion can be inserted, The terminal units are connected to each other by inserting the connecting protrusions into the connected parts, and the earth bar fittings are electrically connected to each other as the terminal units are connected to each other, thereby forming an earth bar. The earth unit is characterized in that the length of the earth bar can be adjusted by changing the number of the terminal units to be connected.

2. The ground bar fitting is provided with blade portions that protrude from the base in the predetermined direction as the connecting protrusions, and blade receiving spring portions that can clamp the blade portions are provided as the connected portions, Furthermore, an insertion port into which the blade unit can be inserted is provided at a position on the base corresponding to the blade receiving spring unit, 2. The earth unit according to claim 1, wherein the blade portion of one of the terminal units is inserted into the base through the insertion port of the other of the terminal units and clamped by the blade receiving spring portion, thereby connecting the terminal units to each other and forming an earth bar by electrically connecting the earth bar fittings to each other.

3. The earth bar fitting is provided with a leaf spring-like abutment piece that protrudes from the base in the predetermined direction and has elasticity in the predetermined direction, and an abutted portion that can be abutted by the abutment piece, an exposure window for exposing the contact portion is provided at a location on the base corresponding to the contact portion, The earth unit according to claim 1, characterized in that, when the terminal units are connected to each other by inserting the connecting protrusion into the connected portion, the abutting piece of one terminal unit abuts against the abutted portion of the other terminal unit in a pressed state, thereby connecting the earth bar fittings to each other and forming an earth bar.

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