JPH023238Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cord pull-out structure for a switch case.

For example, there is a proximity switch having a structure shown in FIG. 1, which detects the presence or absence of an object without contact. In this type of proximity switch, switch case 1
The cord 2 drawn out from the switch case 1 is attached to the switch case 1 for mechanical protection as well as water resistance.
It is pulled out through the rubber bushing 3 inserted into. At the same time, the switch case 1 is filled with resin for the purpose of fixing parts such as the printed circuit board 4 and the detection coil 5 inside the switch case 1, as well as to make the inside of the case completely waterproof.

Therefore, in order to obtain water resistance as described above and at the same time prevent leakage during resin filling, it is most desirable that no gap exists between the cord 2 and the rubber bush 3.

However, if there is no gap between the cord 2 and the rubber bushing 3, that is, if the inner diameter of the rubber bushing 3 is equal to or smaller than the outer diameter of the cord 2, the friction between them will become very large.
The work of inserting the cord 2 into the rubber bush 3 becomes extremely difficult.

It is also possible to strictly set the inner diameter of the rubber bushing 3 in accordance with the outer diameter of the cord 2, but since the dimensions of the cord itself vary widely, there is no point in making the dimensional accuracy of the rubber bushing 3 strict. There isn't.

On the other hand, if a certain gap is set between the cord 2 and the rubber bush 3 in consideration of workability during the cord insertion as described above, there is a risk that the filled resin may leak as described above.

For this reason, in the past, it was unavoidable to set a certain gap between the cord 2 and the rubber bush 3, and as shown in FIG.
To prevent resin leakage, paste the rubber butt 3 with a rubber band etc. to prevent resin leakage, or set the inner diameter of the rubber button 3 smaller than the outer diameter of the cord to account for variations in cord dimensions, at the expense of workability when inserting the cord. Step 3 tightens the cord to prevent resin leakage.

However, in the former case, the process of stitching is added by one step, and in the latter case, the workability when inserting the cord is significantly inferior as mentioned above, and in both cases, the workability is still poor. There are contradictory issues.

This idea was devised based on the above problems, and its purpose was to provide a connector part integrally with the bushing body, and press-fit this connector part into the bushing inlet formed on the switch case side. In addition to having a fitting structure, the cord insertion hole of the bushing body is formed with a larger diameter than the outer diameter of the cord, and the inner peripheral wall corresponding to the connector part position of this cord insertion hole has a substantially triangular cross section around the entire circumference. The object of the present invention is to provide a cord drawer structure for a switch case that solves the conflicting problems mentioned above at the same time by forming a lip piece in the shape of a diaphragm.

Hereinafter, embodiments of this invention will be described in detail based on the drawings.

Figures 3 and 4 show an embodiment of the cord drawer bush in this invention, and 10 is a resin switch case, in which a detection coil 11 and predetermined circuit components are mounted. A printed circuit board 12 is built in, and a detection coil 11 and a cord 1 are connected to the printed circuit board 12.
3 are connected respectively.

Reference numeral 14 denotes a rubber bushing that is attached to the side wall of the switch case 10 and into which the cord 13 is inserted.

A substantially U-shaped bush inlet 20 is formed in one side of the switch case 10, with one end opening toward the upper surface of the edge of the case, and is formed by cutting out the side wall. There is a stepped section 20 in the section.
A is provided.

On the other hand, at one end of a cylindrical rubber bush main body 15 constituting the rubber bush 14, a connector portion 16 that fits into the bush introduction port 20 is integrally formed.
A groove 17 is provided in the groove 17 corresponding to the step portion 20a. Then push the connector part 16 into the inlet 20.
By press-fitting the stepped portion 20a and the groove 1
The positioning is done with 7 and rubber button 14.
The entire body fits tightly into the switch case 10.
It is gaining support.

A cord insertion hole 18 is formed through the bush main body 15 as shown in FIG.
The diameter of the cord 13 is larger than the outer diameter of the cord 13 in order to set a constant gap l between the cord 13 and the cord 13.

A diaphragm-shaped lip piece 19 with a substantially triangular cross section that presses against the outer periphery of the cord 13 is formed on the inner peripheral wall of the end of the cord insertion hole 18 on the side of the connector portion 16 over its entire circumference.

Therefore, according to the above configuration, the rubber bush 1
Since the diameter of the cord insertion hole 18 is set in advance so that a constant gap l is formed between the cord 13 and the rubber bushing 14, the cord 13
Since the only resistance during insertion is the friction between the diaphragm-shaped lip piece 19 and the cord 13, the lip piece 19 is elastically deformed in the direction in which the cord 13 is pulled out and allows relative movement with the cord 13. As a result, the work of inserting the code 13 can be done effortlessly and extremely easily.

On the other hand, if the relative movement between the rubber bush 14 and the cord 13 is stopped, the diaphragm-shaped lip piece 1
9 presses against the cord 13 due to its self-restoring force,
It exerts its original sealing effect and prevents the resin from leaking as described above.

Furthermore, when attaching the rubber button 14 to the switch case 10, conventionally the rubber button 14 is attached to the switch case 10.
4 had to be inserted from the inside of the case, but as a result of adopting the press-fitting structure from the top surface of the switch case 10 as described above, that is, from the top opening side of the edge of the case, the rubber bush 14 itself The installation process is also extremely easy, especially the third one.
As shown in the figure, in consideration of the insertion direction of the printed circuit board 12, the entire switch assembly work including the cord insertion work can be carried out efficiently without being restricted by the narrow space of the switch case. Of course, simply by press-fitting the connector portion 16 of the rubber bush 14 into the bush introduction port 20, the self-elastic force of the rubber bush 14 seals between the two.

As is clear from the above description, according to this invention, the switch case is formed with a bush inlet, while the bush main body is integrally provided with a connector part, and this connector part is placed on the upper opening side of the edge of the case. Since the rubber button is press-fitted into the above-mentioned button inlet, it is possible to easily attach the rubber button to the switch case, including inserting the cord into the rubber button, without being restricted by the limited space of the switch case. .

In addition, according to the present invention, the diameter of the cord insertion hole is made larger than the outer diameter of the cord, and the lip piece is provided in the cord insertion hole corresponding to the connector position, so that the switch case can be easily installed. When the connector part of the bushing is press-fitted into the mouth, the expansion of the bushing is restricted, and the cord in the cord insertion hole is strongly tightened via the lip piece due to the reaction force. This means that good sealing performance can be obtained.

On the other hand, the frictional resistance during cord insertion is extremely small since it is only due to the diaphragm-like lip piece, and the cord insertion work can be carried out extremely easily without these frictions becoming an obstacle.

This not only reliably prevents resin leakage and eliminates the need for pasting with conventional adhesives, but also greatly improves the ease of assembling the switch case as a whole. have

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a proximity switch, Fig. 2 shows a conventional rubber button installed, a view taken along the - line in Fig. 1, and Fig. 3 shows a cord drawer of the switch case of this invention. An exploded view of the structure, FIG. 4 is a sectional view of the cord drawer structure in FIG. 3, and FIG. 5 is an enlarged view of the main part of FIG. 4. 10...Switch case, 13...Code, 1
4...Rubber bushing, 15...Button body, 1
6... Connector part, 18... Cord insertion hole, 19
...Diaphragm-shaped lip piece, 20...Bushy inlet.

Claims (1)

[Scope of Claim for Utility Model Registration] A bush inlet formed by notching the opening edge of the switch case, and a cord insertion hole having a diameter larger than the cord diameter on the outer periphery of the large diameter end of the bush body. A rubber connector part is integrally formed with a groove part on its outer periphery that fits with the inner peripheral edge of the bush inlet port, and the cord is pressed into the cord insertion hole over the entire circumference of the cord insertion hole corresponding to the position of the connector part. a bush integrally formed with a diaphragm-like rubber lip piece having a substantially triangular cross section; a connector portion of the bush is press-fitted into the bush inlet of the switch case to restrict expansion of the bush; A cord drawer structure for a switch case, characterized in that the cord in the cord insertion hole is tightened via the lip piece by the reaction force.