JPS6257437B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates primarily to an automatic tracing detector used in an automatic tracing welding machine to guide a welding torch by tracing the welding groove of a workpiece. More specifically, a detection rod is inserted into a cylinder with one end protruding, the middle part of the detection rod is supported in the cylinder so that it can tilt freely, and the tip of the rod is pressed against the object to be detected and tilts. This relates to an automatic copying detector that performs copying by detecting the position of the inner end, and allows automatic copying to be performed without problems by specifying the position of the inner end of the detection rod at a predetermined position when non-detection occurs. The present invention aims to provide a new automatic tracing detector that enables the following.

BACKGROUND OF THE INVENTION Various types of automatic tracing detectors have been proposed that are placed in the welding head of an automatic tracing welding machine in close proximity to a welding torch and guide the welding torch so as to trace the welding groove. An example of this is the automatic tracing detector published in Japanese Patent Application Laid-open No. 102736/1983. The automatic scanning detector inserts a detection rod into a cylinder so that one end protrudes from the tip of the cylinder, supports the middle part of the detection rod in a tiltable manner, and supports the detection rod inside the cylinder. A means for making the end surface shine is provided, and a plurality of light detecting means for receiving light from the inner end of the detecting rod are provided at positions slightly spaced from the detecting rod toward the opposite protruding end within the cylinder. Such an automatic copying detector has four contact detection elements arranged on the outer peripheral surface of the inner end of a tilting detection rod, and the detection rod and four
Unlike previous automatic scanning detectors that detect the position of the inner end of the detection rod from the state of contact with individual contact detection elements, the position of the inner end of the detection rod can be detected without contact. Therefore, it is possible to avoid the problems that existed in conventional automatic tracing detectors, such as the detection rod being pressed against the workpiece with strong force and the contact detection element being likely to be destroyed by that force. .

As a means for non-contact detecting the position of the inner end of the detection rod, optical means may be used as described in the above publication, but it is also possible to use magnetic means instead. , studies are underway to further improve the automatic scanning detector described in the above publication. However, the automatic tracing detector that detects the position of the inner end of the detection rod in a non-contact manner also has the following problems. In other words, such conventional non-contact automatic tracing detectors cannot specify the initial position of the sensing rod, that is, the position of the inner end of the sensing rod when the sensing rod is not in contact with the welding groove. There was a problem that the setting operation to start the process was incorrect. This issue will be explained in more detail.

Figures 11A and 11B show the initial positional relationship between the spot light from the detection rod and each light detection means, such as a diode, for ambidextrous and unilateral users. I will explain the problem in the case of . In the figure, a ₁ , a ₂ , a ₃ , and a ₄ are light receiving diodes, and S is a spot light from a detection rod. In the case of an ambidextrous person, the spot light S is located as shown by the solid line in Figure A, and the light receiving diode
Only a ₄ is receiving light. That is, Figure 11A
The position of the spot light S shown by the solid line is the spot light S.
This is the ideal initial position. In this state where only the light receiving diode _a4 receives light, the automatic tracing detector guides the welding torch downward, that is, moves downward. Therefore, when starting welding, a welding torch and an automatic tracing detector are positioned above the welding start location and activated. The automatic tracing detector then descends directly below, allowing the welding torch to be guided to the welding start location.

However, in the conventional method, it is not possible to specify the position of the inner end of the detection rod, so the initial position is unstable, and the spot light S may shift to the left or right as shown by the two-dot chain line in Fig. 11A. .
For example, if it shifts to the left in the figure, and as a result, both photodetector diodes _a4 and _a3 receive light, the automatic scanning detector will move to the right while descending. Become.
That is, the automatic tracing detector guides the welding torch diagonally downward to the right. In addition, on the contrary, the initial position of the spot light S tends to shift to the right side in the figure, and as a result, in the automatic scanning detector, both the light receiving diodes _a4 and _a1 receive the light in the initial state. In this case, the welding torch will be guided diagonally downward to the left. This means that proper imitation setting cannot be performed.

Further, even in the case of a single-handed person, there will be a problem if the initial position of the detection rod is not specified. To explain this point with reference to Figure 11B, in the case of a unilateral person, compared to the case of an ambidextrous person, the initial position of the spot light S must be deviated by 45 degrees in central angle from the central axis of the cylinder. No. The left or right side to shift depends on whether you are right-handed or left-handed, but in this example, it is assumed that the shift is to the right in the figure. Then, not only one light-receiving diode _a4 but also the adjacent light-receiving diode _a1 must be in a state where it can receive light. In this situation, when the detection rod is in pressure-free contact, the automatic tracing detector guides the welding torch diagonally downward until the detection rod is in pressure contact with the workpiece, and the detection rod is in pressure contact with the workpiece. Then, one-handed automatic copying will start.

However, the initial position of the spot light S is
If there is a deviation as shown by the two-dot chain line in Figure 1B, for example, if only the light receiving diode _a4 receives light, the automatic scanning detector will drop straight down. Conversely, when the initial position is such that only the light receiving diode _a1 receives light, the automatic scanning detector moves only to the side and does not descend at all. In any case, one-handedness cannot be imitated.

As described above, if the initial position of the inner end of the detection rod deviates from the predetermined position, the setting operation will be erroneous. In the conventional non-contact type automatic scanning detector, it was not possible to specify the initial position of the inner end of the detection rod, so there was a risk that the setting operation would be erroneous.

Problems to be Solved by the Invention However, the present invention has a problem in that it does not specify the initial position of the inner end of the sensing rod, which is tilted when pressed against a welding groove, etc., and therefore there is a risk that the copy setting operation may be erroneous. This is an attempt to solve the problem.

Means for Solving the Problems The means taken by the present invention to solve the above-mentioned problems include a detection rod cradle that defines the position of the inner end of the detection rod when non-detection is occurring inside the cylinder, and a detection rod holder that defines the position of the inner end of the detection rod when non-detection is being performed. A biasing means is provided for pressing the detection rod against the detection rod holder.

Operation In order to adopt the above-mentioned means, according to the automatic scanning detector of the present invention, although it is a non-contact type, the position of the inner end of the sensing rod when not being detected, that is, the initial position, is defined by the sensing rod holder. Therefore, there is no risk that the setting operation will go awry, and it is possible to smoothly transition from the initial state to the welding state.

Embodiments Below, the automatic scanning detector of the present invention will be described in detail according to embodiments shown in the accompanying drawings.

1 to 6 show an example 1 of the automatic scanning detector of the present invention.

In the drawings, 2 is a cylindrical body made of a suitable metal material, and 3 is a detection rod whose middle part is supported within the cylindrical body 2 by a swivel bearing 4 so that it can tilt in 360 degrees. , the tilting fulcrum is located approximately on the central axis of the cylinder 2, for example. The detection rod 3 consists of a rod portion 5 and a contact 6 detachably attached to its lower end. The upper end of the rod portion 5 has a slightly larger diameter, and a reflector storage chamber 7 is provided at the upper end.
is formed. A through hole 8 communicating with the reflector storage chamber 7 is formed in the center of the upper end surface of the rod part 5, and a reflector 1 is formed in the center of the bottom surface 9 of the reflector storage chamber 7.
0 is set.

Reference numeral 11 denotes a detection rod holder attached to the inner surface of the cylinder 2, which is shaped like a cylindrical shape, and is used for detection when the detection rod holder is not detecting (when the detection rod is not pressed by the welding groove). It plays the role of receiving the rod and defining the initial position of the tip of the detection rod.

Reference numeral 12 denotes a holding plate having a circular cross section and fixed to the upper end of the cylinder 2 so as to be able to change its rotation angle.A light emitting diode 14 is provided approximately at the center of the lower surface 13 of the holding plate 12. , furthermore, four light receiving transistors 15 ₁ , 15 ₂ , 15 are arranged on the same circumference centered on the position where the light emitting diode 14 is provided.
₃ , 15 _{and 4} are arranged at equal intervals. Note that a light-receiving diode may be used as the light-detecting means instead of the light-receiving transistor. Then, the light emitting diode 14 and the light receiving transistors 15 ₁ , 15 ₂ , 15
₃ , 15, _{and 4} are each connected to a control circuit (not shown) of an automatic copy welding machine via a lead wire 16. Reference numeral 17 denotes a partition plate protruding from the lower surface of the holding plate 12, and the partition plate 17 separates each of the light receiving transistors 15 ₁ , 15 ₂ , 15 ₃ , 15 ₄ and the light emitting diode 14 from the others. Therefore, when the upper end surface of the detection rod 3 is located below one of the light receiving transistors, for example 15 ₁ , that is, the upper end surface of the detection rod 3 is located below the light receiving transistor 15 ₁ .
When the light from the upper end surface of the detection rod 3 is closest to the other light receiving transistors, for example, 15 ₁ to 1
The light directed toward ₅₄ is blocked by the partition plate 17.

18 ₁ and 18 ₂ are coil springs that urge the rod portion 5 of the detection rod 3 to be pressed against the groove 11a of the detection rod holder 11, and one end of each is supported by the upper end of the rod portion 5 and the bearing 4. The other end is fixed to the inner surface of the cylinder 2. And two springs 18 ₁
The points fixed to the inner surface of the cylinder 2 in ₂ and 18 are spaced apart from each other by about 90 degrees at a central angle when viewed from a plane perpendicular to the axis of the cylinder 2, and the center of the two fixing points and the cylinder The detection rod holder 11 (particularly 11a) is positioned on an extension of the straight line connecting the center axis of the cylinder body 2 (this is only a positional relationship viewed from a plane perpendicular to the axis of the cylinder body 2). (The positions of the detection rod holder 11 and the springs 18 ₁ and 18 ₂ in the longitudinal direction of the cylinder 2 are not necessarily the same.)

As a result, the rod portion 5 of the detection rod ₃ is biased and tilted in the counterclockwise direction in _FIG . It tries to stay in a pressed state. That is, when the detection rod 3 is not pressed against the welding groove, the upper end position is the detection rod holder 1.
1.

In this detector 1, a light emitting diode 14
Light projected downward from the rod portion 5 of the detection rod 3 enters the reflector storage chamber 7 through the through hole 8 on the upper end surface of the rod portion 5, and the incident light is reflected by the reflector 10 and then reflected by the reflector 10. Most of the radiation is emitted upward from the end surface of the rod portion 5 through the through hole 8. When the detection rod 3 is in a tilted state, the light from the detection rod 3 is received by the light-receiving transistor 15 located above the upper end surface of the detection rod 3 (with the detection rod 3 in close proximity); is in a neutral state, that is, its upper end is at the center of the holding plate 12 (where the light emitting diode 14 is located).
is provided. ) or in a state close to its neutral state, no light is received by any of the light receiving transistors 15.
Thus, the state of the detection rod 3 can be detected by detecting the presence or absence of light reception by each of the light receiving transistors 15 ₁ to 15 ₄ .

This automatic copying detector 1 has light receiving transistors 15 ₁ , 15 ₂ , 15 depending on whether the copying is ambidextrous, right-handed, or left-handed.
₃ and 15 ₄ , the springs 18 ₁ and 18 ₂ , and the detection rod holder 11, the relative positional relationship in the circumferential direction of the cylinder body 2 must be changed. The relative positional relationship can be changed by appropriately rotating the holding plate 12 fixed to the upper end portion of the cylinder 2. 6th
The figures show the relative positional relationships in each case, where A shows the case of ambidextrous and B and C show the case of unilateral.

In the case of ambidextrous use, it is necessary to orient the cylinder 2 in the circumferential direction so that the detection rod holder 11 is directly above, as shown in FIG. 6A, and attach it to the welding machine in that direction. Then, by rotating the circular holding plate 12, the light receiving transistors ₁₅₄ and 15 are
An extension of the straight line connecting ₂ is the groove 1 of the detection rod holder 11.
1a. In the case of a unilateral person, as shown in B and C, the cylinder body 2 should be set at 40° compared to the case of an ambidextrous person.
゜Turn it into a rotated state. The direction of rotation differs depending on whether you are right-handed or left-handed.

FIG. 7 shows an overall view of an automatic tracing welding machine using the automatic tracing detector 1 of the present invention. a second slide mechanism 20 that is moved in a direction (up and down) perpendicular to the moving direction of the mechanism 19;
is held by a feed mechanism (not shown) that moves it along the line of the groove 22 of the welding base materials 21, 21, and the movable part 2 of the first slide mechanism 19
3 is a feed screw (not shown) rotated by a left-right DC motor 24 mounted on the slide mechanism 19;
etc., and the movable part 23
The second slide mechanism 20 is fixed to the. The second slide mechanism 20 also includes a movable part 26 that is slid up and down by a feed screw (not shown) or the like that is rotated by a vertically moving DC motor 25 mounted thereon. As a result, the base of the bracket 27 extending in the horizontal direction is fixed, and the tip of the bracket 27 has left and right,
The welding groove 2 of the base metals 21, 21 is adjusted by the adjustment block 28 and holder 29 for finely adjusting the vertical position.
The detector 1 which imitates 2 is held. That is, the position adjustment block 28 has a structure that allows fine adjustment in the same horizontal direction as the first slide mechanism 19 using a knob 30 provided thereon, and the position adjustment block 28 also has a second slide mechanism 20 and a second slide mechanism 20. Knobs 3 that are slightly moved in the same vertical direction
1 is provided, and the holder 29 is integrally connected to the lower end of the shaft 32 via a metal fitting 33,
By operating the knobs 30 and 31, the detection rod 3 of the detector 1 held by the holder 29 can be aligned with the groove 22 of the base materials 21 and 21. Further, a welding torch 3 is attached to the slide 27 at a position slightly behind the adjustment block 28.
4 is fixed perpendicularly to the base material 21. The detector 1 is attached to the holder 29 by inserting the cylinder 2 of the detector 1 from an oblique direction into the mounting hole 35 formed in the holder 29 and tightening the tightening screw 36. conduct. After installing it, knob 3
0 and 31, the positional relationship of the detection rod 3 is adjusted so as to maintain an appropriate position with respect to the welding torch 34. In this case, the detector 1 is supported with its upper end inclined at an appropriate angle in the feed direction of the welding machine (in the direction of the arrow in FIG. 7) with respect to a line perpendicular to the welding base material 21. As described above, the circumferential direction of the cylindrical body 2 must be changed depending on whether the user is ambidextrous or left-handed. Also, cylinder bodies 2 and 4
photodetector transistors 15 ₁ , 15 ₂ , 15 ₃ ,
The direction in the circumferential direction with 15 ₄ also changes depending on the handedness.

The operation of this automatic copy welding machine will be explained below using an example of ambidextrous welding. In this explanation, "top" refers to the side far from the groove 22, "bottom" refers to the side close to the groove 22, and "left" and "right" refer to the side in the feed direction of the welding machine (the direction of the arrow in Fig. 7). It points to the left side and the right side when facing.

The tip of the detection rod 3 of the detector 1 is not pressed against the welding groove 22, and therefore the detection rod 3 is tilted by the springs ₁₈₁ , ₁₈₂ so that the center axis of the detection rod substantially faces the light receiving transistor ₁₅₄ . When the detection rod 3 is in the pressed state, the detection rod 3 is held by the detection rod holder 11, and its position, that is, the initial position is defined. In this state, the vertical motion DC motor 25 reverses,
The movable part 26 is lowered. As the movable part 26 descends, the welding torch 34 integrated with the bracket 27 and the detector 1 are lowered toward the groove 22, and the tip of the detection rod 3 comes into contact with the groove 22, causing the detection rod 3 to spring up. 18 ₁ , 18 ₂ and rotated _{slightly clockwise} in FIG. It will be facing towards the center of the circumference. Then,
The light from the upper end of the detection rod 3 is no longer received by any of the light receiving transistors 15, and at the same time, the rotation of the vertical motion DC motor 25 is stopped, and at the same time, the lowering operation of the movable part 26 of the slide mechanism 20 is also stopped. As a result, the welding torch 34
This means that it has been set at the optimal position for the welding groove No. 21.

When the entire copy welding machine including the first and second slide mechanisms 19 and 20 is fed by a feed mechanism (not shown), the detector 1 traces the groove 22 on the base metals 21 and 21, and is guided by it for welding. torch 34
The grooves 22 are sequentially welded. At this time,
If the line of the groove 22 has a bend in the plane direction of the base material or an undulation in the thickness direction of the base material, the detection rod 3 follows this and rotates around the bearing 4 as a fulcrum, and the light from the upper end of the detection rod 3 is emitted. The light is received by a certain light-receiving transistor 15, and the deviation of the detection rod 3 from the neutral state is detected. Then, the DC motor 2
4 and 25 rotate forward or backward, each slide mechanism 19, 20 moves left and right or up and down, and the welding torch 34 always follows the groove line.

In addition, in such an automatic copying detector 1, it is possible to detect whether or not the detection rod holder 11 and the detection rod 5 are in contact with each other, and use the detection signal, that is, the contact detection signal, as a sequence step signal, etc. This is preferable for building an automatic welding system. FIG. 8 shows one cycle of automatic copy welding by a welding machine, and an example of the use of the contact detection signal will be explained with reference to this diagram. The position shown at A in FIG. 8 is the tracing start position, and the detection rod 3 starts to descend from this position, and when it descends to the position shown at B, the detection rod 3 is pressed against the welding base material 21. Then, the detection rod 3 separates from the detection rod holder 11 and enters a non-contact state. Therefore, the contact detection signal falls from "1" to "0". Therefore, in synchronization with the fall of the contact detection signal,
Welding is started and the welding machine is set to proceed while automatically tracing along the tracing direction. next,
As shown in FIG.
When the detection rod 3 reaches the hole 37, the detection rod 3 is in a non-pressure contact state, the detection rod 3 is held on the detection rod holder 11, and the detection rod holder 11 and the detection rod 3 are in a contact state. As a result, the contact detection signal changes from "0" to "1".
stand up. Therefore, copying is stopped in synchronization with this rise, and the welding machine 1 is switched to a state in which it simply moves straight. By doing so, a collision between the welding torch 34 and the welding base material 21 can be avoided. This is because automatic copying detector 1 is in hole 3.
If the copying operation is not stopped when the automatic copying detector 1 reaches the position above 7, the automatic copying detector 1 will descend due to the copying operation, and there is a risk that the welding torch 34 will descend accordingly and collide with the base material 21. However, in such a case, if the tracing is stopped at the rise of the contact detection signal, the sheet passes through the hole 37 immediately. Then, when the automatic copying detector 1 passes through the hole 37, the detection rod 3
The detection rod 3 returns to the state in which it is pressed into contact with the detection rod holder 11, and the detection rod 3 is brought out of contact with the detection rod holder 11. Therefore, the contact detection signal falls from "1" to "0". Therefore, the automatic copying operation may be restarted in synchronization with this rise.

Furthermore, when the automatic copying detector reaches the end of the base material 21 and leaves the base material 21 as shown in D in FIG. '' to ``1'', but it is only necessary to start pulling up after the time required to weld the remaining portion has elapsed from this rise. This is because in the state shown in FIG. 8D, the automatic copying detector 1 is separated from the base material 21,
The welding torch 34 itself is still located on the base metal 21. Therefore, in such a case, automatic copying detector 1
If the automatic tracing continues, the welding torch 34 will descend due to the automatic tracing operation, and as a result, the welding torch 34 will descend and collide with the welding base material 21. However, at this time, if the tracing is stopped based on the change in the contact detection signal and the lifting is started with a time difference, it is possible to weld to the end and avoid the above-mentioned collision. The position shown at E in FIG. 8 is the position after the lifting is completed.

In this way, it would be very beneficial to detect the contact state between the detection rod 3 and the detection rod holder 11 and use the contact detection signal for welding sequence control.

In the automatic scanning detector of the present invention, an optical means is used to detect the tilting state of the detection rod 2, and depending on whether or not the detection rod 2 is close, the detection rod 2 is detected as either "1" or "0".
Automatic copying is performed using on/off control (digital control method) that generates value signals (digital signals). However _{, a} proportional control _method ( _analog control It is also possible to perform automatic copying using the following method. FIG. 9 shows the detection circuit used in that case (however, the left and right light receiving transistors 15 ₃ ,
Since the circuit consisting of 15 _{and 1} is exactly the same, it is not illustrated. ). Figure 10 shows the detection rod 3.
This shows the relationship between the vertical position at the inner end (horizontal axis) and the main force Out (vertical axis) of the detection circuit shown in Figure 9, and uses a proportional control range where the input/output characteristics are almost completely linear. and control. In Figure 10, the neutral area is the area where the detection rod is pressed with moderate force.
If the neutral region is exceeded, an over range occurs in which no movement is made to move the automatic copying machine upward or downward, and an operation to move the automatic copying machine upward or downward is performed. The initial position is located outside the proportional control area. The operation of the detection circuit made up of the left and right light-receiving transistors 15 ₃ and 15 ₁ is the same.

According to such a proportional control method, automatic copying with higher precision becomes possible.

In the present invention, the tilting state may be detected by magnetic means or the like. For example, four magnetic coils or the like may be arranged in place of the four light-receiving transistors, and a magnet may be arranged at the upper end of the detection rod 3 instead of a reflector, and the inside of the detection rod 3 may be placed at the upper end of the detection rod 3. The tilting state of the detection rod 3 may be detected by magnetically detecting the proximity state of the ends. In that case, a magnetic transducer element such as a semiconductor Hall element may be used in place of the magnetic coil.

That is, in the present invention, various types of proximity detection means can be used regardless of the type of proximity detection means as long as they are non-contact type.

Further, the detection rod holder 11 does not necessarily have to be shaped like a cylindrical body; for example, a pair of pins may be installed on the inner surface of the cylinder, and the rod portion 5 of the detection rod 3 is held between them when the detection rod is not detected. The shape of the detection rod holder is not limited to that of the above embodiment, for example, the initial position of the detection rod 3 may be regulated thereby.

Effects of the Invention As described above, according to the automatic scanning detector of the present invention, the position of the inner end of the detection rod when not being detected is determined by the detection rod holder. Therefore, it is possible to eliminate the possibility that the initial setting operation will be erroneous. Therefore, it becomes possible to smoothly transition from the initial state to the welding state.

[Brief explanation of the drawing]

Figures 1 to 6 are for explaining an example of implementation of the automatic scanning detector of the present invention, with Figure 1 being a sectional view and Figure 2 being an enlarged sectional view showing the inner end of the cylinder of the detection rod. , FIG. 3 is an enlarged perspective view with the main parts cut away,
FIG. 4 is a sectional view taken along the line 4-4 in FIG. 1, and FIG. 5 is an enlarged perspective view showing the spring forming part cut away.
6A to 6C are explanatory diagrams showing the different positional relationships between the detection rod holder and each proximity detection means, and FIG. 7 shows an example of an automatic tracing welding machine in which the automatic tracing detector of the present invention is used. An overall perspective view, FIG. 8 is an operation explanatory diagram showing one cycle of welding operation to explain an example of the use of a signal for detecting contact between a detection rod holder and a detection rod,
9 and 10 are for explaining another embodiment of the automatic scanning detector of the present invention. FIG. 9 is a detection circuit diagram, and FIG. 10 is a diagram showing the input/output characteristics of the circuit shown in FIG. 9. In the curve diagrams shown in FIG. 11, A and B are explanatory diagrams of the problems of the prior art, in which A shows an ambidextrous case, and FIG. 11 B shows a unilateral person. Explanation of symbols, 1...Automatic copying detector, 2...Cylinder, 3...Detection rod, 11...Detection rod holder, 15...
...Proximity detection means, 18... energizing means.

Claims (1)

[Claims] 1. A detection rod is inserted into a cylinder so that one end thereof protrudes from the tip of the cylinder, an intermediate part of the detection rod is supported in a tiltable manner within the cylinder, and the detection rod is inserted into the cylinder so that the detection rod is tilted in the cylinder. Providing a plurality of proximity detection means for detecting the proximity of the ends,
Automatic copying characterized in that a detection rod holder for defining the position of the inner end of the detection rod when non-detection is provided inside the cylinder, and a biasing means for pressing the detection rod against the detection rod holder during non-detection. Detector. 2. Automatic scanning detection according to claim 1, characterized in that the relative positional relationship between the detection rod holder and the plurality of proximity detection means in the circumferential direction of the cylinder can be changed. vessel.