JPH0139371Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is installed in a distribution board in a single-phase three-wire or three-phase four-wire low-voltage circuit, and is used to measure the insulation resistance of the circuit and load. This relates to a polar terminal (hereinafter simply referred to as a neutral polar terminal).

The case of measuring the insulation resistance of a low voltage circuit and a load using such a neutral terminal will be explained based on the single-phase three-wire low voltage circuit shown in FIG. In Fig. 1, L is a load, and this load L is connected to the branch wiring sheath breaker MCB and the neutral terminal NS, and the neutral copper band 12 is attached to the neutral terminal NS. ing. When measuring the insulation resistance between the circuit and the load or ground, disconnect the branch wiring disconnector MCB, open the neutral terminal NS, and connect the load terminal 2 and the neutral terminal. The connection with the copper strip 12 is then cut, and the voltage is measured via the voltage terminal 14, the load terminal 2, and the neutral copper strip 12 using a megger, a tester, or the like. The neutral terminal NS has a contact within the insulating case that connects to the load terminal 2 and the neutral copper band 12, and when the neutral terminal NS is to be in an open circuit state, this contact is This is done by moving the load terminal 2 and separating it from the neutral copper band 12.

However, the conventional neutral terminal has a large number of parts to move the contact and its structure is relatively complicated, resulting in high production costs and stable opening/closing operations of the neutral terminal. It had the disadvantage that it tended to lack consistency and certainty.

The object of the present invention is to solve the above-mentioned drawbacks of the conventional products by simplifying and special devising the structure of the contact as a means for moving the contact in the neutral terminal.

An example of implementing the present invention will be described with reference to the attached drawings. Reference numeral 1 denotes an insulating case that has a side wall on one side and an opening on the other side, and is formed so that it can be stacked, and a cover (not shown) can be attached to the opening. A load terminal 2 is attached to one side of the housing, and a neutral copper strip 12 is inserted into a lower opening 13. Neutral copper band 12
is attached to the lower piece 3c of the L-shaped contact portion 3 disposed inside the insulating case 1 via a mounting screw 17, and the tip protrusion 3a of the contact portion 3 is attached to the contact portion of the load terminal 2. It is arranged opposite to 2a. 4 is a contact having a contact portion 4a at one end, a contact portion 4b at the other end, and a protrusion 4c in the shape of an inverted U in the center.
By slidably fitting both sides of the letter-shaped protrusion 4c into a fitting groove 15 provided in the insulating case 1, the protrusion 4c is arranged to be movable in the vertical direction within the insulating case 1. has been done. The lower surface of the almost inverted U-shaped protrusion 4c of the contactor 4 and the insulating case 1
A pressure contact spring 5 is installed between the lower surface of the contactor 4 and the contact portion 4 of the contact 4.
a and the contact portion 4b are simultaneously pressed against the lower surface of the contact portion 2a of the load terminal 2 and the lower surface of the tip protruding portion 3a of the contact portion 3 of the neutral copper strip 12. A leaf spring 9 is placed on the upper surface of the substantially inverted U-shaped protrusion 4c of the contactor 4, and one end thereof is engaged with an engagement groove provided in the insulating case 1. On the top of the leaf spring 9, the leaf spring 9
An operating handle 6 having a cam 7 at its tip that contacts the upper surface of the insulating case 1 is rotatably disposed on the insulating case 1 via a pivot 8 attached to the cam 7. The contact portion of the cam 7 with the leaf spring 9 is provided with a curved portion 7a and a straight portion 7b following the curved portion 7a. Operation handle 6
The axis 8a of the pivot 8 is located on the vertical extension line of the point of application C (shown in the sixth figure) where the resultant load of the pressure spring 5 acts on the lower surface of the substantially inverted U-shaped protrusion 4c of the contact 4. ing. The leaf spring 9 is held between the cam 7 of the operating handle 6 and the approximately inverted U-shaped protrusion 4c of the contact 4, and the load of the leaf spring 9 is applied to both of them. However, the load on the leaf spring 9 is set to be weaker than the load on the pressure contact spring 5. 10 and 11 are a first stopper wall and a second stopper wall provided in the upper part of the insulating case 1 for stopping the rotation of the operation handle 6 during opening and closing operations of the neutral terminal;
In the drawings, the first stopper wall 10 is formed on a horizontal surface that comes into contact with the lower surface 6a of the operating handle 6 during a circuit-closing operation, and the second stopper wall 11 is formed on a vertical surface that contacts the upper surface 6b of the operating handle 6 during an opening operation. ing. Therefore, the operating handle 6 is set to rotate within a range of 90 degrees between the first stopper wall 10 and the second stopper wall 11 when opening and closing the neutral terminal. 14 is a voltage terminal for measuring insulation resistance.

When incorporating the neutral terminal according to the above embodiment into a distribution board, attach the neutral copper strip 12 to the lower piece 3c of the contact portion 3 extending to the lower surface opening 13 of the insulating case 1 via the screw 17. and attach mounting stands (not shown) made of insulating material to both ends of the neutral copper strip 12.
This mounting base is fixed to a distribution board, and in this case, neutral terminals can be stacked as many as the required number of circuits.

Next, the operation of the neutral terminal according to the above embodiment will be explained. In the state shown in FIG.
This shows the closed circuit state of the neutral terminal, which is simultaneously pressed against the tip protrusion 3a of the contact portion 3 connected to the neutral copper band 12 by the pressing force of the pressing spring 5, and in this case, the contact Since the load of the leaf spring 5 interposed between the upper surface of the almost inverted U-shaped protrusion 4c of the contact 4 and the lower surface of the cam 7 of the operating handle 6 is set to be weaker than the load of the pressure contact spring 5, the contact is held at the above-mentioned position, while the curved portion 7a of the cam 7 is constantly pressed upward by the leaf spring 9. That is, the operating handle 6 is given a clockwise rotational force about the pivot 8 by the pressing force of the leaf spring 9, and as a result, the operating handle 6 has its lower surface 6a provided in the insulating case 1. The first stopper wall 10 is held in a horizontal state in contact with the first stopper wall 10. In this state, to open the neutral terminal, the operating handle 6 is rotated counterclockwise.
Then, the cam 7 rotates while its curved portion 7a presses the upper surface of the leaf spring 9, and as a result, the contact 4
resists the pressing force of the pressure contact spring 5, and is almost the opposite U.
With the letter-shaped protrusion 4c sliding downward within the fitting groove 15, it begins to move downward within the insulating case 1. Further, when the operating handle 6 is rotated counterclockwise over the entire stroke of 90 degrees until its upper surface 6b collides with the second stopper wall 11 inside the insulating case 1, the straight portion 7b of the cam 7 will be brought into contact with the upper surface of the leaf spring 9. Since the contacts 4 are brought into close contact with each other and the contact 4 moves downward the maximum distance, the contact portion 4a and the contact portion 4b at both ends thereof are
The neutral electrode terminals are separated from the tip projections 3a of the contact portions 3 connected to the contact portions 2a of the load terminals 2 and the neutral copper strip 12, respectively, and the neutral electrode terminals are in the open state as shown in FIG. in this case,
As shown in FIG. 6, the length of the linear portion 7b of the cam 7 is such that the combined load of the pressure contact spring 5 acts on the lower surface of the approximately inverted U-shaped protrusion 4c of the contactor 4. They are set at appropriate lengths so that they are located at equal distances from the point of application C, and the axis 8a of the pivot 8 of the operating handle 6 is located on the vertical extension of the point of application C. , the D dimension (distance between the axis 8a of the pivot 8 and the right end F of the straight portion 7b of the cam 7) shown in FIG.
a and the center portion G of the straight portion 7b of the cam 7). Therefore, in order to bring the operating handle 6 into the position where the neutral terminal is closed as shown in the second figure, the pressure contact spring 5 must be bent by a distance of dimension D - dimension E. Since it is necessary to apply a clockwise rotational force, when the neutral terminal is in the open state, the operating handle 6 is locked in a vertically erect state with its upper surface 6b abutting against the second stopper wall 11. is retained. Then, from this open state to the neutral terminal,
To achieve the closed circuit state shown in FIG. 2 again, rotate the operating handle 6 in the state shown in FIG. 3 clockwise until the lower surface 6a thereof collides with the first stopper wall 10.
Then, as the pressing force from the operating handle 6 is gradually released, the contact 4 guides the sliding movement of the fitting groove 15 of the approximately inverted U-shaped protrusion 4c by the restoring force from the pressure contact spring 5. The contact portion 4a and the contact portion 4b at both ends of the contactor 4 are the tip protruding portions of the contact portion 3 that connect to the contact portion 4a of the load terminal 2 and the neutral copper strip 12, respectively. 3a at the same time, resulting in the closed circuit state shown in FIG.

For example, as shown in FIG. 9, a conventional neutral terminal has a pressure contact spring 2 between a contact part of a load terminal 2 provided in an insulating case 30 and a contact part 27 of a neutral copper strip 12.
An operator 23 is disposed on the upper surface of the contactor 21 that contacts simultaneously with the pressing force of 5, and has a cam 24 at its tip that contacts the upper surface, and is rotatably mounted on the insulating case by a pivot 29. By rotating the operating handle 22, the contact 21 is moved downward via the operating element 23 against the pressing force of the pressure contact spring 25, and the connection between the load terminal 2 and the neutral copper strip 12 is easily established. It had a structure that cut it off. 28 is a play prevention spring for the operating handle 22, and 14 is a voltage terminal. Therefore, in this conventional neutral terminal, the operating element 23 is used as a component for moving the contact 21 downward.
Therefore, in order to satisfy the request to keep the area occupied by the neutral electrode terminal as small as possible, it is not possible to provide a large space on the lower surface of the contact 21, so the pressure contact spring 25 is This has the disadvantage that the mounting dimensions cannot be made large and the contact pressure between the contact portion of the load terminal 2 of the contactor 21 and the contact portion 27 of the neutral copper strip 12 cannot be strengthened; If the pressure is to be strengthened, a large space must be provided on the bottom surface of the contact 21 in order to increase the installation size of the pressure spring 25, so the neutral copper strip 12 must be placed along the side surface of the insulating case. Coupled with this, it is difficult to satisfy the requirement to keep the area occupied by the neutral terminal as small as possible, and it is difficult to arrange each component rationally within a limited space. have. In other words, the operator 23
Because of the need for This method has the disadvantage that it is not possible to simultaneously strengthen the contact pressure on the contact portion. Furthermore, in this conventional neutral terminal, since the contact 21 is moved downward via the operating element 23 which is separate from the contact 21, the downward movement of the contact 21 and the pressure contact spring 25 are prevented. During the upward movement due to the restoring force, the movement of the contact 21 is not regulated in any way, and as a result, the stability of the movement of the contact 21 in the vertical direction tends to be somewhat lacking, and the neutral terminal Before and after opening/closing operations, there is a risk that the contact point between the contact portion of the load terminal 2 of the contactor 21 and the contact portion of the neutral copper band 12 may not always be constant, and as a result, the stability of the energized state may be somewhat lacking. be.

On the other hand, in the present invention, since the neutral terminal is constructed as described above, the drawbacks of the conventional neutral terminal described above can be overcome.

That is, in the present invention, the contactor 4 has a contact part 4a and a contact part 4b at both ends, and has a substantially inverted U shape in the center.
It has a structure in which a letter-shaped protrusion 4c is provided, and when the contactor 4 is rotated with the operating handle 6, the leaf spring 9
Since the contact 4 is moved downward against the pressing force of the pressure contact spring 5, the operating element 23 provided in the conventional neutral terminal described above is not required for the downward movement of the contact 4. Therefore, the number of component parts of the neutral terminal can be reduced compared to the conventional one, and the overall configuration can be made as simple as possible and the price can be made low. can. By forming the central part of the contactor 4 into an upwardly bent inverted U-shaped protrusion 4c, a space is formed on the lower surface of the contactor 4, and the pressure contact spring 5 is formed using the space. This eliminates the need to provide a considerably large space on the bottom surface of the contact in order to strengthen the contact pressure between the contact of the load terminal and the contact of the neutral copper strip, as was the case in the past. Therefore, there is a margin for attaching the neutral copper strip 12 to the bottom surface of the insulation case, and the limited space of the insulation case can be used effectively to arrange each component in a rational manner. , the contact pressure of the contactor can be sufficiently strengthened even in a limited space. In addition, the center part of the contact 4 is formed into an upwardly bent inverted U-shaped protrusion 4c, and the pressure spring 5 is mounted using the space created on the lower surface of the protrusion 4c. A (as shown in the second diagram)
can be set to be larger than the operational deflection amount B of the pressure spring 5 (the vertical movement distance of the contact 4) (shown in Figure 3), so even if the load on the pressure spring 5 is increased, the The maximum stress can be made appropriate and reasonable, and the _l1 dimension (distance between the axis 8a of the pivot 8 and the curved part 7a of the cam 7) and _l2 dimension (of the operating handle shown in FIG. 7) The ratio of the distance between the axis 8a of the pivot 8 and the tip of the operating handle 6 can be selected to be large, and the operation is easy even though the load of the pressure contact spring 5 is large, that is, the contact pressure of the contactor 4 is large. The rotation operation of the handle 6 does not require much force, and the operation handle 6 can be operated smoothly and easily. Furthermore, since the center part of the contact 4 is formed into an upwardly bent inverted U-shaped protrusion 4c, this inverted U-shaped protrusion 4c is fitted into the fitting groove 15 provided in the insulating case 1. By fitting together, the vertical movement of the contactor 4 within the insulating case 1 is always regulated (guided) by the fitting groove 15, and therefore, unlike the conventional products described above,
The contact point between the contact portion 4a of the contact 4 and the contact portion of the load terminal 2, the contact portion 4b of the contact 4, and the neutral copper band 1
The point of contact with the contact portion 3 of the neutral electrode terminal is always constant before and after the opening/closing operation of the neutral electrode terminal, and the stability of the energized state can be maintained. Note that the rotation operation of the operating handle 6 is performed with an angular difference of 90 degrees between the first stopper wall 10 in the horizontal state and the second stopper wall 11 in the vertical state, so that the cam 7 follows the curved portion 7a. A straight part 7b of a predetermined length is provided, and when the neutral terminal is in an open state, this straight part 7b forms an inverted U of the contact 4.
A leaf spring 9 placed on the upper surface of the letter-shaped protrusion 4c
If the operating handle 6 is brought into close contact with the first stopper wall 10 in the closed state, the operating handle 6 is held constant in a horizontal state with its lower surface 6a in close contact with the first stopper wall 10 by the pressing action of the leaf spring 9 as shown in FIG. 5, and in the open state. In this case, the straight part 7 of the cam of a predetermined length is
Due to the close contact of b to the leaf spring 9, the operating handle 6 is constantly maintained in a vertical state in which its upper surface 6b is in close contact with the second stopper wall 11, so that the open/closed state of the neutral electrode terminal can be clearly and easily confirmed. As a result, it is possible to prevent accidents caused by misidentification of the open/closed state.

In the above embodiment, the contact portion 4b of the contactor 4 was shown to be in contact with the terminal piece-shaped contact portion 3 connected to the neutral copper band 12.
The arrangement may be changed so that it is in direct contact with the neutral copper strip 12.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a single-phase three-wire system using a distribution board neutral terminal, Figures 2 to 8 show an example of implementing the present invention, and Figure 2 shows a distribution circuit in a closed circuit state. 3 is a vertical sectional view of the same as above in an open state; FIG. 4 is a front view of the leaf spring 9; FIG. 5 is a partially enlarged vertical sectional view of FIG. 2; The figure is a partially enlarged vertical sectional view of FIG. 3, FIG. 7 is a front view of the operating handle 6, FIG. 8 is a front view of the contactor 4,
FIG. 9 is a longitudinal sectional view of a conventional distribution board neutral terminal in a closed circuit state. 1... Insulating case, 2... Load terminal, 3... Neutral copper strip contact part, 4... Contact, 4a... Contact part, 4b... Contact part, 4c... Almost inverted U-shaped protrusion Part, 5...pressure spring, 6...operation handle, 7...
Cam, 8...axis, 9...leaf spring, 12...neutral copper band.

Claims (1)

[Scope of utility model registration request] An insulating case having a side wall, a contact part connected to a load electronic contact part provided in the insulating case at one end, and a contact part of a neutral copper strip attached to the insulating case at the other end. a contactor having a contact portion that comes into contact with the contactor and having a central portion protruding in an approximately inverted U shape and disposed movably in the vertical direction within an insulating case; and a substantially inverted U-shaped protrusion of the contactor. A press-contact spring is disposed between the bottom surface of the contactor and the insulating case, and presses the contact portions at both ends of the contactor to the contact portions of the load electronic and the contact portion of the neutral copper strip, respectively; It has a leaf spring disposed on the upper surface of the approximately inverted U-shaped protrusion, and a cam at the tip that contacts the upper surface of the leaf spring, and rotates to the insulating case via a pivot attached to this cam. A neutral electrode terminal for a distribution board, comprising an operation handle that is arranged so as to open and close a connection between a load terminal and a neutral copper strip through the contactor.