JPH019311Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a proximity switch, and in particular to an improvement of its cap.

Conventionally, this type of proximity switch has a threaded portion 2 provided on the outer periphery of a housing 1, as shown in FIG. 1, and tightening rings 3, 4 provided on this threaded portion 2. When setting the operating position of the switch, use a scale or gauge to measure the distance between the sensitive surface 6 of the switch and the detected object 8.
The distance L was measured and the switch was placed in a stable operating position, but it took a considerable amount of time to set the position, and when setting the switch, the
When the detected object 8 collides with the sensing surface 6, there is a risk that not only the sensitive surface 6 will be damaged, but also the assembly such as the core housed in the housing 1 will be damaged.

This invention is intended to eliminate such conventional drawbacks, and one embodiment of this invention will be described below with reference to the drawings.

That is, in FIG. 2, the switch housing 1
A threaded portion 2 is provided on the outer periphery of the switch, and this threaded portion 2 is attached to a tightening fitting (not shown) for attaching the switch, and this fitting is attached to a tightening ring 3,
4 are screwed together. A core, a detection coil, and a switching circuit are formed inside the housing 1.
An assembled body such as an IC circuit board (none of which is shown in the figure) is accommodated, and a cable 5 connected to the IC circuit board is led out of the housing 1.
A sensitive surface 6 is formed at one end of the housing 1, and a cap 7 for protecting the sensitive surface 6 is detachably attached to the end on the sensitive surface 6 side by screwing. This cap 7 is made of, for example, acetal resin, and does not affect the detection of the object 8 to be detected. The thickness of the bottom plate of the cap 7, that is, the distance d from the inner bottom surface in contact with the sensitive surface 6 to the outer surface, is set approximately equal to the stable operating distance of the switch. Here, the stable operating distance and standard operating distance will be explained just in case.

The standard operating distance is the average starting distance for each switch among the operating distances of the switches.

On the other hand, the stable operating distance is within the standard operating distance.
The operating distance fluctuates due to changes in temperature, power supply, and voltage, so it refers to the distance at which the device can operate stably even when these conditions change, and it is shorter than the standard operating distance and approximately half of the standard operating distance. .

Therefore, when using the proximity switch with the above configuration, the cap 7 can remain attached to the switch.Moreover, in order to install the switch, the outer surface of the cap 7 must be attached to the switch, and the outer surface of the cap 7 must be exposed to the detection target. It is sufficient to bring the switch into contact with the body 8 once, move the switch slightly backward from this state, and attach it using the tightening rings 3 and 4.

Also, if the thickness of the bottom plate of cap 7 is approximately half of the standard operating distance, then standard operating distance > stable operating distance > 1/2 of standard operating distance, so the thickness of the bottom plate of cap 7 is Since it is slightly shorter than the stable operating distance, this provides stable operation and a margin during installation.

In this invention, as described above, a cap 7 made of resin is fitted to the end of the sensitive surface 6 side of the housing 1 forming the switch, which protects this end and does not affect the detection of the detected object 8 in any way. At the same time, since the thickness of the bottom plate of this cap 7 is approximately half of the standard operating distance, even if the detected object 8 accidentally collides with the sensitive surface 6 side, the sensitive surface 6 or the assembly inside the housing 1 will be damaged. Not only does it not cause damage to the attached body, it does not require measuring instruments such as scales or gauges to set the operating position of the proximity switch with respect to the detected object 8, and the operating position can be easily adjusted. The advantage is that you can expect various functions.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a conventional proximity switch, FIG. 2 is a side view showing an embodiment of the proximity switch according to the present invention, and FIGS. 3A and 3B are a front view and a side view of a cap, respectively. 1...Housing, 2...Threaded part, 3, 4...
Tightening ring, 5... cable, 6... sensitive surface, 7...
...cap, 8...object to be detected.

Claims (1)

[Scope of utility model registration request] A resin cap 7 that protects this end and does not affect the detection of the detected object 8 in any way is fitted to the end of the sensitive surface 6 side of the housing 1 forming the switch, and the bottom plate of this cap 7 is fitted. A proximity switch whose thickness is approximately half the standard operating distance of the above switch.