JP2014002950A - Terminal block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal block which can always maintain continuity regardless of a screwed state of the terminal screw and the presence or absence of deterioration in component parts without disconnection of a circuit.SOLUTION: A terminal block of the present invention comprises a housing for containing a fixed conductive plate disposed to have an electric conduction with other parts; an electric wire holding part which can hold an electric wire end by screwing a terminal screw; and an elastic body, from an opening side. By this configuration, screwing and unscrewing of the terminal screw and an energizing force of the elastic body act independently, the electric wire holding part can move between the fixed conductive plate and the elastic body, and the electric wire holding part comes into contact and fixed with the fixed conductive plate by the energizing force of the elastic body or the energizing force of the elastic body and the screwing of the terminal screw to always maintain the continuity. Also, in a state where only the energizing force of the elastic body (preferably, a spring) acts, the electric wire holding part can be moved to be in contact with and separated from the fixed conductive plate with an external force being applied. On the opening side of the housing, a cover plate is provided to prevent the unscrewed terminal screw from falling.

Description

  The present invention relates to a terminal block that can always maintain a conductive state regardless of a screwed state of a terminal screw.

  In the measurement for confirming the soundness of the operation of the electrical equipment, particularly in the insulation resistance measurement, it is necessary to disconnect a part of the circuit. For example, the case of measuring the insulation resistance of an instrument transformer (hereinafter referred to as a transformer) installed in a power generation substation is taken as an example. FIG. 7 shows an example of a current circuit on the secondary side of the transformer. In FIG. 7, the secondary output lines 35 of transformers CT1 to CT3 (351 to 353 are phase output lines and 354 are common lines) are protected relays R via terminal blocks T1 to T4 and test terminals TT1 to TT4. And is grounded from the terminal block T4 of the common wire 351 through the crossover wire 36 and the terminal block T5 (see FIGS. 7B and 7C). When measuring insulation resistance, it is necessary to disconnect the ground wire 37 connected to the transformer CT at the terminal block. However, each time the insulation resistance is measured, the terminal screw 39 is loosened at the terminal block T5, the ground wire 37 is removed, and after the measurement is completed, the terminal screw 37 is again fastened to the terminal block T5 and connected. There was a problem that it was very time-consuming.

  The following proposals have been made as methods that can solve such problems. The proposal of Patent Document 1 is a terminal block in which a blade-shaped contact piece can be inserted and removed in a substantially intermediate region, and a circuit including the terminal block can be disconnected by pulling out the blade-shaped contact piece. The proposal of Patent Document 2 has three terminals, a main terminal, an auxiliary terminal (measurement terminal), and a movable terminal. The main terminal and the movable terminal are always connected, and the movable terminal is pulled out. Thus, the circuit is switched from the main terminal to the auxiliary terminal. In addition, the proposal of Patent Document 3 is a terminal block using a spring-like conductor piece having a substantially U-shape in side view at the wire connection portion, and utilizes the fact that the spring at the other end is lifted by pressing one end of the spring. Can be inserted and removed.

Japanese Utility Model Publication No. 4-42065 JP-A-5-82916 Japanese Utility Model Publication No. 3-64471

  However, the proposals of the above patent documents have the following problems. In the proposals of Patent Documents 1 and 2, the disconnection means can be easily performed with a simple structure. However, after the measurement, the operator needs to restore the circuit, and there is a risk that the operator forgets to restore. is there. In addition, the circuit has a structure in which the conduction state of the circuit cannot be visually recognized from the outside, and there is a problem that it cannot be confirmed whether or not the restoration work is completed. In addition, in the proposal of Patent Document 3, there is a risk of recovery forgetting by the operator as in the above proposals, and when the spring of the component part deteriorates and breaks, there is a concern that the electric wire may come off naturally. In particular, the electrical equipment in the power transmission and distribution system has a problem that it is not preferable from the viewpoint of the stability of power supply.

  In order to solve the above-mentioned problems, the present invention provides a terminal block that can always maintain a conductive state regardless of whether or not a terminal screw is screwed in or a component is deteriorated or damaged, and does not cause a circuit disconnection. With the goal.

  According to the present invention, the object is that a terminal screw, a fixed conductive plate having a relatively larger size than a screw shaft of the terminal screw and having a through-hole through which the screw shaft can be inserted, and a lower side thereof An electric wire holding portion that is disposed and holds the electric wire end portion by tightening the terminal screw and makes electrical contact between the electric wire end portion and the fixed conductive plate by contacting the fixed conductive plate; and An elastic body arranged on the lower side thereof, and an electric wire insertion port that each accommodates and arranges the electric wire end portion so that the electric wire end portion can be directly inserted into the electric wire holding portion from a direction substantially perpendicular to the axial direction of the terminal screw. And an electric insulating casing having the terminal screw is rotated in the loosening direction so that the head is separated from the electric wire holding portion, and the electric wire holding portion holds the electric wire end portion. The elasticity while maintaining the state By the action of the biasing force and the external force applied to the terminal screws to resist its is achieved by the terminal block, characterized in that so as to swing freely separable to the fixed conductive plate.

  As described above, the terminal block of the present invention includes a fixed conductive plate arranged to energize other parts, a wire holding part capable of holding the end of the wire by tightening the terminal screw, and an elastic body. It is housed in the body from the opening side. Thereby, the tightening and loosening of the terminal screw and the urging force of the elastic body act independently, and the wire clamping portion can move between the fixed conductive plate and the elastic body, or the urging force of the elastic body, or By this and tightening of the terminal screw, the electric wire holding part is brought into contact with and fixed to the fixed conductive plate, and the conductive state is always maintained. In addition, in a state where only the urging force of the elastic body is applied, the electric wire holding portion can be moved so as to be able to contact and separate from the fixed conductive plate by receiving an external force.

As described above, the terminal block of the present invention accommodates the fixed conductive plate, the electric wire holding portion, and the elastic body in the housing, and allows both the tightening by the terminal screw and the biasing force of the elastic body to act independently. Since the wire holding portion that holds the end of the wire by screwing the terminal screw is always brought into contact with the fixed conductive plate by the screwing of the terminal screw and the urging force of the elastic body, the conductive state is maintained. it can. This means that the conductive state can be maintained only by the urging force of the elastic body even when the terminal screw is rotated in the loosening direction and its head is separated from the wire clamping portion. Thereby, even if the worker looses the terminal screw and then forgets to restore it, the conductive state can be maintained by the urging force of the elastic body as described above, and thus the occurrence of an accident can be prevented. Even when the elastic body is damaged, it is possible to maintain a conductive state between the wire holding portion and the fixed conductive plate by tightening the terminal screw.
Furthermore, by applying an external force in the axial direction to the head of the terminal screw, the electric wire holding portion is separated from the fixed conductive plate against the urging force of the elastic body while holding the electric wire end portion. It is possible to disconnect between the end portion of the electric wire and the fixed conductive plate, and to be electrically disconnected. This eliminates the need to remove and cure terminal screws and wire ends as in the prior art to open and close the circuit during measurement, and reduce the risk of ground faults and short circuits due to mixed wiring.

It is a fragmentary sectional perspective view which shows one Embodiment of the terminal block of this invention. It is a cross-sectional front view of embodiment shown in FIG. It is a cross-sectional side view of embodiment shown in FIG. It is a cross-sectional front view which shows another example of embodiment of the terminal block of this invention. FIG. 5 is a cross-sectional side view of the embodiment shown in FIG. 4. It is a figure explaining the implementation condition of the insulation resistance measurement in embodiment shown in FIG. It is a figure which shows the current measurement circuit of the conventional protective relay.

  Hereinafter, embodiments of a terminal block according to the present invention will be described in detail with reference to the accompanying drawings. 1 is a perspective view showing an embodiment of a terminal block of the present invention, FIG. 2 is a sectional front view of the embodiment shown in FIG. 1, and FIG. 3 is a sectional side view of the embodiment shown in FIG. As shown in these drawings, in the terminal block 1 of the present embodiment, an electric wire including a terminal screw 10, a fixed conductive plate 12, a first holding piece 15, and a second holding piece 17 inside an insulating housing 8. The clamping part 14 and the compression coil spring 20 as an elastic body are sequentially accommodated in the tightening direction of the terminal screw 10. Between the first holding piece 15 and the second holding piece 17 of the electric wire holding portion 14, a round crimp terminal 25 at the end of the electric wire is inserted. In addition to the crimp terminal, the wire core wire itself or other forms of terminals can be used at the end of the wire depending on the type of terminal block, so that these are included without limitation below. , And referred to as “wire end 25”. Further, as the terminal screw 10, various conventionally known ones such as those having no washer and those having a washer as in the illustrated example can be used.

  The housing 8 in the present embodiment has a box shape with the top opening in the figure. This insulative housing is used for the use part and application of the terminal block of the present invention (for example, used as a relay terminal block or used as a terminal equipped in a measuring device, etc.), and of the device on which the terminal block is installed. The outer shape can be designed as appropriate depending on design and the like. In FIG. 1, for convenience of describing the configuration inside the housing 8, illustration of a front surface having a wire insertion opening (not shown) into which the wire end 25 is inserted is omitted. It is assumed that the electric wire insertion port is provided at a position where the electric wire end 25 can be inserted between the first holding piece 15 and the second holding piece 17 in the holding portion 14.

  The fixed conductive plate 12 is a belt-like body fixed substantially parallel to the bottom surface in the housing 8, and feeds power from the other part (not shown) to the wire end 25 connected to the terminal block 1 through this, Alternatively, on the contrary, power is supplied from the wire end portion 25 to another portion (not shown) through this end. Here, the “other part (not shown)” is, for example, a relay terminal block having a pair of terminals, and corresponds to the other terminal paired with the illustrated terminal. When equipped, it corresponds to the internal circuit of the electric device.

  In the present embodiment, a through hole 13 penetrating in the thickness direction is formed in a substantially circular shape near the end on the front side of the fixed conductive plate 12 so as to allow the screw shaft of the terminal screw 10 to pass therethrough. It is installed. The size (inner diameter) of the through-hole 13 is set to be relatively larger than that of the screw shaft of the terminal screw 10 and relatively smaller than the diameter of the head of the terminal screw 10. Thus, even if there is some play in the swing of the first holding piece 15 and the second holding piece 17 of the electric wire holding portion 14 to which the terminal screw 10 is screwed, the screw shaft of the terminal screw 10 is The fixed conductive plate 12 is not contacted.

The first holding piece 15 and the second holding piece 17 in the electric wire holding section 14 are substantially rectangular plate-like bodies each having a size that can be accommodated in the housing 8 in plan view. Screw holes 16 and 18 into which the screw shafts of the terminal screws 10 are screwed are formed in the intermediate regions of these plate-like bodies. 1 to 3, the second holding piece 17 is shown to be thicker in the screw axis direction of the terminal screw 10 than the first holding piece 15, but both holding pieces 15, 17 hold the end of the electric wire. If the inside of the housing 8 can be swung in this state, the thicknesses of both can be set as appropriate. Moreover, the mutually opposing surface of the 1st clamping piece 15 and the 2nd clamping piece 17 is between both clamping pieces toward the edge part by the side of an electric wire insertion port from the intermediate area so that it may be easy to insert the electric wire edge part 25. The theater can be enlarged continuously or intermittently to form a trumpet shape in a side view.

  In the housing 8, a compression coil spring 20 is disposed below the second sandwiching piece 17. The compression coil spring 20 has a wire clamping portion 14 that clamps the wire end 25 without being tightened by the terminal screw 10. On the other hand, an urging force that can be pressed and brought into contact with the fixed conductive plate 12 is applied to the electric wire holding portion 14. When an external force is applied to the electric wire holding portion 14 along the screw shaft of the terminal screw 10, the urging force is easily applied. The wire diameter, coil diameter, and number of turns can be set as appropriate so that the spring constant is such that the wire holding portion 14 can be separated from the fixed conductive plate 12 against the above. In addition, the compression coil spring 20 may or may not be fixed at both ends of the second clamping piece 17 and the bottom surface of the housing 8.

  In the terminal block 1 of the present embodiment, a groove is provided in a circumferential wall facing the upper end portion of the housing 8 toward the upper end and substantially parallel to the extending direction of the fixed conductive plate 12, and an electrically insulating material is formed along the groove. A cover plate 22 which is a formed plate-like body is fitted substantially horizontally. An opening 23 is formed in the cover plate 22 at a position just above the head of the terminal screw 10 in a state where the cover plate 22 is fitted in the groove. The opening 23 does not allow the head of the terminal screw 10 to pass therethrough, but is preferably set to a hole diameter that allows a tool such as a screwdriver to pass therethrough for tightening and loosening the terminal screw 10.

  With the above configuration, the terminal block 1 of the present invention is such that the terminal screw 10 and the urging force of the compression coil spring 20 act, and the wire holding portion 14 holding the wire end 25 is always in contact with the fixed conductive plate 12. It is possible to maintain the conduction state. This is because even if the terminal screw 10 is not tightened, the electric wire clamping portion 14 is brought into contact with the fixed conductive plate 12 only by the urging force of the compression coil spring 20 and the electric conduction state therebetween. As a result, the occurrence of an accident due to circuit disconnection can be prevented.

  4 is a front sectional view showing another example of the embodiment of the terminal block of the present invention, and FIG. 5 is a sectional side view of the embodiment shown in FIG. In the embodiments shown in these drawings, a compression coil spring 26 is further fitted as an elastic body between the head of the terminal screw 10 and the fixed conductive plate 12, and the head of the terminal screw 10 is separated from the fixed conductive plate 12. It is different from the embodiment shown in FIG. 1 to FIG. 3 in that it is biased in the direction in which it is applied, and other configurations are essentially unchanged.

  In the embodiment shown in FIGS. 4 and 5, whether or not the terminal screw 10 is tightened as long as the terminal screw 10 is screwed to both the first holding piece 15 and the second holding piece 17 of the wire holding portion 14. Regardless, the wire clamping portion 14 can be brought into contact with the fixed conductive plate 12 by the two compression coil springs 20 and 26, and the terminal screw 10 is tightened and the two compression coil springs 20 and 26 are tightened. With this urging force, the electric wire clamping portion 14 can be always brought into contact with the fixed conductive plate 12 and the electrical conduction state between them can be maintained. (Also in this case, the conductive state can be maintained regardless of the screwed state of the terminal screw.)

  According to the configuration of each of the above embodiments, the electrical continuity between the electric wire holding portion 14 and the fixed conductive plate 12 is always maintained, and the operator loosens the terminal screw 10 and performs measurement or the like to tighten it. Even if it is forgotten or when the compression coil spring 20 or 26 is deteriorated or damaged, the circuit is disconnected by this, the conduction state is released, and an accident caused by the disconnection does not occur.

  In any embodiment, for example, by loosening the terminal screw 10 until its head comes into contact with the cover plate 22, measurement such as insulation resistance measurement can be performed on the terminal block 1. FIG. 6 is a view for explaining the handling of the terminal block of the embodiment shown in FIG. 1 at the time of measuring the insulation resistance, and each of the diagrams (a) to (c) is shown in FIG. It is a cross-sectional front view of a terminal block similarly to FIG. In the terminal block 1, the terminal screw 10 in the tightened state (see FIG. 6A) is loosened until its head abuts against the cover plate 22 (see FIG. 6B). In this state, the wire clamping portion 14 comes into contact with the fixed conductive plate 12 by the urging force of the compression coil spring 20, and the fixed conductive plate 12 is held in a conductive state via the wire end portion 25 and the wire clamping portion 14. Next, the measuring needle 31 at the tip of the megger measuring probe 30 is applied to the head of the terminal screw 10 and pressed in the axial direction of the screw so that the electric wire holding portion 14 is separated from the fixed conductive plate 12 and electrically connected therebetween. (See FIG. 6C). This makes it possible to configure a ground electrode in the insulation resistance measurement of the transformers CT1 to CT3, and subsequently enable insulation resistance measurement.

  After the insulation resistance measurement is completed, the pushing by the megger measuring needle 31 is stopped, and the terminal screw 10 is tightened, so that the wire holding portion 14 comes into contact with the fixed conductive plate 12, and the wire end portion and the wire conductive portion are in a conductive state. . At this time, even if the operator forgets to tighten the terminal screw 10, the conduction state can be maintained by the biasing force of the sub-compression coil spring 20 (or 26). Even if the compression coil spring 20 (n or 26) is damaged after the terminal screw 10 is tightened, the conduction state can be maintained by tightening the terminal screw 10. Moreover, in the terminal block 1 of embodiment shown in FIG.1 and FIG.2, it replaces | exchanges an internal conductive component by making it possible to attach or detach the electrically insulating cover board 22, and to remove this when needed. Etc.

  The terminal block of the present invention can be effectively used as a terminal block equipped in electrical equipment and as a relay terminal block. In particular, it is most suitable for use on a terminal block that has a high possibility of pressing a megger measuring needle of an insulation resistance meter when measuring insulation resistance.

DESCRIPTION OF SYMBOLS 1 Terminal block 10 Terminal screw 11 Screw shaft 12 Fixed electrically conductive board 13 Through-hole 14 Electric wire clamping part 15 1st clamping piece 16, 18 Screw hole 17 2nd clamping piece 20 Compression coil spring 22 Cover board 24 Electric wire 25 Electric wire end (round) Type crimp terminal)
30 Megger measuring probe 31 Measuring needle 35 CT secondary output line (354 is common)
CT1-CT3 transformer

Claims (4)

Terminal screws,
A fixed conductive plate having a relatively larger size than the screw shaft of the terminal screw and having a through-hole through which the screw shaft can be inserted;
An electric wire holding device that is arranged below and clamps the end of the electric wire by tightening the terminal screw and makes electrical contact between the electric wire end and the fixed conductive plate by contacting the fixed conductive plate And
Furthermore, an elastic body arranged on the lower side,
Each of which is housed and disposed, and includes an electrically insulating housing having a wire insertion opening that allows the wire end portion to be directly inserted into the wire holding portion from a direction substantially perpendicular to the axial direction of the terminal screw. And
By rotating the terminal screw in the loosening direction, the head part is separated from the electric wire holding part, and the electric wire holding part maintains the holding state of the electric wire end part and the urging force of the elastic body. A terminal block, wherein the terminal block swings in contact with and away from the fixed conductive plate by an action of an external force applied to the terminal screw so as to resist.   The said housing | casing has a through-hole which enables the effect | action of the external force with respect to the said terminal screw, and is further provided with the cover board which restrict | limits the separation distance from the said electric wire clamping part of the said terminal screw. Terminal block.   The terminal block according to claim 2, wherein the cover plate is detachably attachable to the housing.   The terminal block according to claim 1, wherein the elastic body is a compression coil spring.

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