JPH0743682Y2 - Reel type optical fiber sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of an optical fiber sensor.

[Conventional technology and its problems]

In this type of optical fiber sensor, the sensor body and the detected portion are optically connected by an optical fiber, but the distance between the sensor body and the detected portion varies depending on the usage environment.

Thus, conventionally, an optical fiber is connected to the sensor main body through a connector, and an optical fiber of an appropriate length is connected according to the distance between the sensor main body and the detected portion, or an optical fiber is used each time. Was to be cut on site. However, the former is not rational because it requires preparing optical fibers of various lengths with connectors attached in advance. Further, the latter has a drawback that a special tool is required for cutting the optical fiber and the detection accuracy is not stable due to the variation of the cut surface. Further, in the case of an optical fiber using glass fiber, there is a fatal defect that it cannot be easily cut on site.

Therefore, as a solution to these problems, as shown in FIG. 3, the LED, the photo IC, the amplifier, etc. are housed inside the reel type body (a) while the end of the optical fiber (b) is After facing the above LED and photo IC,
There is a structure in which an optical fiber (b) is wound around the main body (a) (see JP-A-60-118804).

However, the photoelectric switch having the above structure does not rotate the reel-shaped main body (a) itself, but the optical fiber (b) must be manually wound or unwound around the outer circumference of the main body (a). However, there are various inconveniences such as that the optical fiber (b) once wound is unraveled due to its elasticity, which makes it inconvenient to store.

An object of the present invention is to provide a highly accurate sensor in which the length of the optical fiber can be easily adjusted according to the distance between the sensor body and the detected part, and the optical fiber once housed does not come apart. To do.

[Means for Solving the Problems]

To achieve the above object, the sensor of the present invention rotatably accommodates a reel in a case, and an optical fiber for projecting and receiving light is wound around the reel, and its tip side can be pulled out from the case. Further, the base end face is exposed from both ends of the rotation axis of the reel, while the light emitting element and the light receiving element are provided in the case so as to face the base end face of the optical fiber.

[Action]

The present invention according to the above technical means allows the reel to be rotated and the accommodated optical fiber to be pulled out from the case by the required length by pulling the tip of the optical fiber, and again by rotating the reel in the opposite direction. While the optical fiber can be wound around the reel to shorten the length of the optical fiber, the base end face of the optical fiber and the light emitting / receiving element are arranged in a line on the rotation axis of the reel. Although it is in contact, even if the reel rotates, it always maintains an optically coupled state. Further, since the reel is housed in the case, it has an effect of being regulated by the inner surface of the case even if the wound optical fiber is separated.

〔Example〕

Hereinafter, the structure of the present invention will be described in more detail with reference to an embodiment shown in the drawings. 1 is a case having an opening 1a in the upper surface and two mounting holes 1b in the lower portion, 2 is an opening 1a of the case through a packing 2a. A lid 3 for sealing the optical fiber is a reel for winding the optical fiber.
It is rotatably supported inside. Reference numeral 5 is an optical fiber for projecting and receiving light, and when it is wound around the reel 3, its base end surfaces 5a, 5a pass through the inner holes 3a, 3a of the reel, respectively.
While exposed on both end surfaces of the rotating shaft 3b of the reel, the tip side
5b and 5b can be pulled out from the insertion opening 1c on the front surface of the case 1. Reference numerals 6 and 6 denote printed circuit boards provided on the inner surfaces of both sides of the case 1.
The LED 7 and the photo IC 8 as a light receiving element are arranged so as to face the rotation shaft 3b of the reel, respectively, so that they are always opposed to the base end faces 5a and 5a of the optical fiber. Further, 9 is a stopper lever which is provided so as to face the insertion opening 1c on the front surface of the case 1 and which has a rubber member 9a in contact with the optical fiber 5 so that the fiber can be pressed.

In the figure, 10 is a cord connected to the printed circuit board 6 from the rear surface of the case 1, 11 is an operation indicator lamp, and 12 is a variable resistor, which are housed in the upper part of the case 1. Furthermore,
Reference numeral 13 denotes a detection head attached to the tip of the optical fiber 5.

Next, the usage of the sensor according to the present invention in the above example will be described. First, when pulling out the optical fiber 5, if the detection head 13 is pulled outward, the reel 3 in the case 1 rotates and the optical fiber 5 is inserted. Delivered from 1c. Then, when the desired length is pulled out, the stopper lever 9
When the upper end side of is pressed, the rubber material 9a in the lower part is pressed against the optical fiber 5 to fix it. Then, in this state, the optical fiber is set to a predetermined length, and the case 1
The insertion port 1c is prevented from entering water drops and the like by pressing the stopper lever 9 into contact therewith. On the other hand, the opening at the top of the case
Since 1a is also sealed by the lid 2 via the packing 2a,
Each electronic component in the case 1 is not adversely affected by water droplets. On the other hand, if the optical fiber 5 is to be housed, the lid 2 is opened and the reel 3 is rotated in the opposite direction through the opening 1a of the case, the fixing by the stopper lever 9 is released and the optical fiber 5 is wound around the reel 3. Of.

Thus, since the base end surfaces 5a and 5a of the optical fiber 5, the LED 7 and the photo IC 8 face each other on the rotation axis 3b of the reel 3, the two are always optically coupled even when the reel 3 rotates. To maintain a good condition.

[Effect of device]

The optical fiber sensor of the present invention rotatably accommodates the reel around which the optical fiber is wound in the case, allows the tip side of the optical fiber to be pulled out from the case, and exposes the base end surface of the optical fiber to both ends of the rotary shaft of the reel. Since the light emitting element and the light receiving element are arranged facing each other, the optical fiber can be pulled out from the case by a required length, and the optical fiber can be accommodated by rotating the reel in the opposite direction. In other words, this sensor does not use any tools or connectors for the length of the optical fiber,
Moreover, it is possible to freely set it by simple handling. Further, even when a large number of sensors are attached, the work efficiency can be greatly improved.

Further, since the base end face of the optical fiber and the light emitting and receiving elements face each other on the rotation axis of the reel, the optical coupling between the two is always maintained even if the reel rotates, and highly accurate detection is possible. It has the particular advantage of being possible.

Furthermore, since the optical fiber wound on the reel is stored in the case, it is convenient for storage without being disassembled due to the elasticity of the optical fiber itself and it is also possible to protect the optical fiber from impact. It has various excellent effects.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of the sensor of the present invention, FIG. 2 is a lateral sectional view thereof, and FIG. 3 is a front view showing a conventional example. In the figure, 1 ... Case, 3 ... Reel, 5 ... Optical fiber, 7 ... LED, 8 ... Photo IC.

Claims (1)

[Scope of utility model registration request] 1. A case 1 in which a reel 3 is rotatably housed, an optical fiber 5 for projecting and receiving light is wound around the reel 3, and a front end side 5b thereof can be pulled out from the case, and a base end surface 5a is provided. The reel type optical fiber is characterized in that the light emitting element 7 and the light receiving element 8 are provided in the case 1 so as to be exposed from both ends of the rotation shaft 3b of the reel 3 and face the respective base end surfaces 5a of the optical fibers 5. Sensor.