JPS59155703A - Gap position detection device using transmitted light - Google Patents

Abstract

PURPOSE:To reduce the size by a method wherein a gap position detector is composed of a light projector and a plurality of light detection elements and the projector is provided to one side of an object which has a gap to be detected and the deection elements detect the light from the projector provided to another side through the gap. CONSTITUTION:A pair of long pipe pieces 1A are arranged symmetrically about a seam 1B which is a gap. A lamp 3 is lighted on one side of the pipe pieces 1A by a source from a light projector 2. The lamp is fixed to a supporting frame 4 made of a highly heat-conductive material such as aluminum. Becuase the pipe 1 is moved along the direction of the paper surface, the lamp 3 and the supporting frame 4 are provided inside the pipe pieces 1A. Therefore, a filter 5 is provided between the lamp 3 and the pipe 1 to protect the lamp 3. An array 6 of a plurality of optical fibers is provided to another side of the pipe 1 perpendicular to the longitudinal direction of the pipe 1. The light transmitted through the gap delta of the seam 1B of the pipe 1 is detected by an array of phototransistors T1-Tm through the optical fiber array 6 and the signal is transferred to a light detection processing unit 8 through a cord 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a gap position detection device particularly suitable for use in seam vibe welding and the like.

[Prior art]

A seam pipe is made by bending a long steel plate to form a circular gap sleeve having a gap, and then welding the gap, such as laser welding or TIG welding, to form a hollow pipe. When welding is performed automatically, it is necessary to detect the gap position in advance before welding. Since the gap meander from side to side along the length of the gap sleeve, it is not easy to accurately measure the gap.

Conventional methods for detecting seams, which are gaps, include mechanical detection methods that involve inserting a probe into the seam and making contact, magnetic sensor methods that utilize the leakage magnetic flux effect caused by magnetism, and optical detection methods that utilize transmitted or reflected light. Although there are sensor methods, the optical sensor method has been used because it does not wear out and has excellent sensitivity and accuracy.

Among the optical sensor systems, the reflective type is typified by industrial television cameras, and has the drawback of increasing both equipment and cost.

[Purpose of the invention]

An object of the present invention is to provide a miniaturized gap position detection device.

[Summary of the invention]

The gap position detection device of the present invention includes a light projector placed on one side of the gap mantle and an object to be detected, and a plurality of light receiving elements that receive light from the light projector placed on the other side through the gap. The aim is to achieve the above objectives.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be explained using a gap position detection device shown in FIG.

A pair of elongated pipe pieces IA are arranged in correspondence with each other via a joint IB, which is a gap. The joint IB is welded using a welding machine (not shown) to form the pipe 1 that integrates the pipe pieces IA. On one side of the pipe piece IA, a lamp 3 is lit by power from the projector 2. The lamp 3 is fixed to a support frame 4 made of aluminum or the like having good thermal conductivity. Since pipe 1 moves in the direction of the paper, pipe piece I
A lamp 3 and a support frame 4 are arranged within A. For this reason, a filter 5 is provided between the lamp 3 and the pipe 1 to protect the lamp 3.

The filter 5 may be a flat plate, but may also have a concave or convex surface to produce parallel light.

A plurality of optical fiber arrays 6 are arranged on the other side of the pipe 1 and are arranged in a direction perpendicular to the longitudinal direction of the pipe 1. The light transmitted through the gap δ of the joint IB of the pipe 1 passes through the optical fiber array 6 to the phototransistor array T! shown in FIG. ~T, and is transmitted as a signal to the light reception processing unit 8 via the code 7.

That is, in FIG. 2, the luminous flux Pl-P- from the lamp 3
In this case, only P2 passes through the seam gap δ and is connected to the phototransistor 'I' t through the corresponding optical fiber array 6.
□ Out of Tn, only T2 is sensitive, and the sensor output signal S
Of +-8-, S2 is output separately from the others. Usually, the optical fibers are arranged at intervals that are approximately the same as the gap δ (here, in the order of 0.1 to 0.3). That is, the phototransistor is connected to the light receiving surface via an optical fiber array.

The light reception processing section 8 performs processing corresponding to the seam detection signal S2, such as commands and displays to move a welding torch (not shown) to the seam position.

In this manner, according to the gap position detection device of the present invention, a plurality of optical fibers 6 having a small diameter are arranged in the storage case 6A, so that they can be stored closely.

As a result, since the optical fibers are in close contact with each other, the distance between the optical fibers can be about 0.1 to 0.3 fins. Therefore, it is possible to detect even thin seams, and
The gap position detection device can be downsized.

Furthermore, by arranging the optical fiber 6 on the upper surface side of the pipe 1, the optical fiber will not be damaged by spatter during welding.

In addition, in the above-mentioned embodiment, explanation was given using a pipe as an example.
Any member having a gap may be used.

〔Effect of the invention〕

As described above, the gap position detection device of the present invention can be downsized.

[Brief explanation of drawings]

FIG. 1 is a schematic side sectional view of a gap position detection device shown as an embodiment of the present invention, and FIG. 2 is an equivalent circuit of FIG. 1. 1... Pipe, IB... Gap, 3... Lamp, 6
・・・Kofu Figure 1 Figure 2

Claims (1)

[Claims] 1. In an apparatus for detecting an object to be detected, a gap formed in the object, and a position of the gap, the gap position detection device comprises:
1. A gap position detection device using transmitted light, comprising a light projector on one side of an object to be detected, and a number of light receiving elements that receive light from the light projector through a gap on the other side. 2. The gap position detecting device using transmitted light according to claim 1, wherein an optical fiber is used as the light receiving element.