JPS604384Y2 - Terminal block - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a terminal block for connecting electrical equipment, electrical components, etc. to an external wiring circuit.

Generally, with regard to terminal blocks, consideration is given to the method of fixing the terminal pieces.

FIG. 1 is a plan view showing the structure of a conventional terminal block, and FIG. 2 is a front view thereof.

The terminal block main body 1 is integrally molded from synthetic resin, and has a terminal piece insertion groove 1a and a relief six 1b when tightening the terminal screw 3 during wiring.
etc. are provided.

FIG. 3 is an enlarged cross-section of the terminal piece 2 inserted into the terminal piece insertion groove 1a.

The groove width A is made wider than the width a of the terminal piece 2, and the groove height B is made slightly smaller than the claw height C of the terminal piece 2.

FIG. 4 is a plan view of the conventional terminal piece 2, and FIG. 5 is a side view of the same.

A plurality of screw holes 2a and a protrusion 2b are provided on the side surface of a part of the terminal piece 2.

Next, the assembly and operation of the above-mentioned parts will be explained.

When the terminal piece 2 is inserted into the insertion groove 1a of the terminal block body 1, the groove width is A.
is larger than the terminal piece width a, so it can be easily inserted up to the protrusion 2b, and if it is completely inserted, the groove height B is greater than the terminal piece plate thickness t and smaller than the protrusion height C, so the spring action of the protrusion allows the terminal piece 2 to be inserted. is fixed, and the terminal piece 2 will not move or generate noise in the groove 1a due to the vibration of the electrical equipment.

Furthermore, when the screw 3 is tightened during wiring, it passes through the terminal block main body 1 up to the screw clearance 61b, so that it also acts as a stopper to prevent the terminal piece 2 from being removed, making it more stable.

However, since the structure is fixed by the spring action of the notch 2b, tensile stress is generated on the surface near the center of the terminal piece 2.

Therefore, there is a risk of stress corrosion cracking.

Brass is generally used as the material for the terminal piece 2 because it requires conductivity and strength of the threaded portion, but this material is the most susceptible to cracking among practical alloys.

Stress corrosion cracking occurs near the protrusion 2b where the tensile stress is greatest.

In this case, a fatal defect is poor conduction.

Furthermore, as is clear from FIG. 5, since one side of the protrusion 2b is cut off, there is a problem with the directionality when inserting the terminal piece 2 into the insertion groove 1a of the terminal block main body 1, which reduces assembly work efficiency. .

In order to improve the above-mentioned drawbacks, it is possible to use materials that are less likely to cause stress corrosion cracking, such as pure copper or phosphor bronze, but these are expensive.

Also, it would be possible to change the structure of the terminal block main body 1 and embed the terminal piece 2, but this would reduce productivity and become expensive.

The present invention provides a terminal block that is inexpensive, has good productivity, and is free from poor continuity due to stress corrosion cracking.

Figures 6 and 7 show a terminal piece 2 showing an embodiment of the present invention.
It is.

That is, the protrusion 2b is pressed onto the terminal piece 2 at four locations so that a predetermined distance 1 is left between the end face side of the outer diameter of the threaded portion 2a in the terminal piece insertion direction and the center of the protrusion 2b.

The height C of this protrusion is the same as that of the conventional product, and the protrusion shape is formed into an arc shape with no cut surfaces at both ends of the protrusion 2b in the terminal piece insertion direction, as shown in FIG.

This terminal piece 2 has no cut surface of the protrusion 2b on the back side, and there are a total of four protrusions 2b on both ends, so there is no directionality when inserting it into the insertion groove 1a of the terminal block main body 1, and workability is good.

Even if stress corrosion cracking occurs after it is installed in an electrical device, it will not result in poor continuity because the stress corrosion crack will be at the center of the protrusion 2b where the stress is maximum and there will be a distance of 1 from the outer diameter of the threaded portion 2a.

Further, since the terminal screw 3 is tightened during wiring, the terminal piece 2 will not come off.

In this embodiment, the center position of the protrusion 2b is placed on the side with a distance l from the threaded part, but the effect is the same even if it is placed in the center as shown in FIG.

Also, the shape of the protrusion does not have to be an arc shape, for example, a trapezoid shape,
Needless to say, an inverted triangular shape may also be used.

As described above, according to the present invention, even if brass, which has good marketability, is used as the material for the terminal strip, there is no continuity failure due to stress corrosion cracking, and since there is no directionality in inserting the terminal strip, it is easy to work and is inexpensive. We can manufacture terminal blocks.

[Brief explanation of the drawing]

Figures 1 to 5 show conventional terminal blocks, Figure 1 is a plan view of the conventional terminal block, Figure 2 is its front view, and Figure 3 is an enlarged view of the terminal block inserted into the terminal block. 4 is a plan view of the terminal piece, FIG. 5 is a side view thereof, FIG. 6 is a plan view of the terminal piece showing an embodiment of the present invention, FIG. 7 is a side view thereof, and FIG.
The figure shows another embodiment of the terminal piece according to the present invention. 1 is a terminal plate, 1a is a terminal piece insertion groove, 2 is a terminal piece, 2a is a screw portion, and 2b is a protrusion portion. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] The terminal block has a terminal block main body having a terminal piece insertion groove, a plurality of screw parts into which terminal screws for connecting conductive wires are screwed together, and a protrusion having a spring action, and the terminal block uses the spring action of the protrusion. a terminal piece that is inserted and fixed into the terminal piece insertion groove of the main body; A terminal block that is integrally provided by molding a terminal piece molding material so that there are no cut surfaces at both ends in the terminal piece insertion direction.