JP2000015453A - Automatic stop device in misalignment or chipping of projection nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem such as misalignment and chipping of a projection nut in the projection welding. SOLUTION: In an automatic stop device in the misalignment or chipping of a projection nut, a misalignment detection tip 6 comprising a bottomed cylindrical body 2, an O-ring 4 and an insulation member 5 is mounted on a lower end part of an electrode tip 1, a detection plate 8 is provided on an electrode holder 7 which holds the electrode tip 1 and is vertically moved by an air cylinder, etc., through an appropriate frame, a sensor fitting arm 9 is provided on the appropriate frame of a spot welding machine, and a photosensor 10 is provided on a tip part of the sensor fitting arm 9 opposite to the detection plate 8 so that the machine can be stopped in the condition where the nut is abnormally fed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding method for a projection nut in which a spot welding machine is automatically stopped in any case where the supply position of the nut is not normal so that defective products are not generated. The present invention relates to an automatic stop device for shifting or chipping.

[0002]

2. Description of the Related Art Conventionally, a misalignment detecting chip 6 as shown in FIG. 2 has been used in order to prevent misalignment of a nut in spot welding of a projection nut or failure caused by energization at the time of chipping. This conventional misalignment detection chip 6
Is fitted to the lower end of the electrode tip 1 having a hole into which the upper half of the projection nut 11 fits, and the misalignment detecting chip 6 is attached to the lower surface of the bottomed cylindrical body 2. An insertion hole 3 into which the upper half of the nut is fitted is provided. An O-ring 4 for gripping the electrode tip 1 is fitted on the inner surface of the cylindrical body 2, and the electrode tip 1 and the bottomed cylindrical main body 2 are provided on the inner wall surface and the lower end. For example, an insulating member 5 such as a nylon sleeve is attached in order to achieve insulation. In addition, 12 is a workpiece.

[0003] When projection welding of the nut is performed using the conventional misalignment detecting chip 6, if the misalignment of the nut or the supply of the nut in the opposite direction occurs, the upper half of the projection nut 11 is inserted with the detecting chip 6. Since it does not enter the hole 3, it does not come into contact with the electrode tip 1 and the nut 11 cannot be welded. That is, the nut 11
This is because energization is prevented by the insulated bottomed cylindrical body 2.

[0004]

In the conventional misalignment detecting chip 6, when the nut is missing, that is, when the nut is not supplied, or when the nut is misaligned and supplied in the opposite direction, the nut is prevented from being energized. The occurrence of poor welding can be prevented. However, in addition to the above-mentioned state, there is a nut supply error in which the nut is supplied vertically. In this case, the nut is welded and a defective product is generated. Further, since the machine does not stop even in the case of these abnormal states, there is a problem that a defective product in which a nut is missing may occur due to carelessness of an operator. Furthermore, since the machine does not stop, there is a problem that it cannot be applied to an automation line.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and in addition to a conventional misalignment detecting chip, an electrode holder 7 for holding an electrode chip 1 is provided.
Is provided with a detection plate 8 and a light sensor 10 on an appropriate sensor mounting arm 9 of the spot welder, so that the spot welder is automatically stopped in case of any failure in the supply of the nut. It is.

That is, according to the automatic stop device of the present invention when the projection nut is misaligned or chipped, the lower end of the electrode tip 1 has an insertion hole for fitting the upper half of the nut to the lower surface of the bottomed cylindrical body 2. 3, an O-ring 4 for holding the electrode tip 1 on the inner surface of the cylindrical body 2 and a misalignment detecting chip 6 formed by attaching an insulating member 5 to the inner surface and the lower end of the cylindrical main body. On the other hand, a detection plate 8 is provided on an electrode holder 7 which holds the electrode tip 1 and moves up and down by an air cylinder or the like via a suitable frame. Further, a sensor mounting arm 9 is provided on a suitable frame of the spot welding machine.
And a light sensor 10 is provided at the tip end of the sensor mounting arm 9 so as to face the detection plate 8. The above-described misalignment detection chip 6 detects misalignment of the nut and a supply state in the opposite direction. The light sensor 10 is characterized in that, in addition to the nut supply state, the nut is chipped, and the machine can be stopped when the nut is supplied vertically.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIG. FIG. 1 is a partial longitudinal sectional view of an automatic stop device according to the present invention when the projection nut is misaligned or chipped. According to the present invention, in addition to the conventional misalignment detecting chip 6, the spot welding machine is automatically stopped in case of any trouble in the supply of the nut by providing the detecting plate 8 and the light sensor 10. is there.
The form and mounting method of the misalignment detecting chip 6 are exactly the same as those in the related art, and a detailed description thereof will be omitted.

[0008] The detection plate 8 according to the present invention comprises the electrode chip 1
And is attached to an electrode holder 7 which moves up and down by an air cylinder or the like. In addition, the light sensor 1
Numeral 0 uses a reflection type beam sensor, and the light sensor 10 has the detection plate 8 at its tip end via a sensor mounting arm 9 fixed to an appropriate frame of a spot welding machine.
It is attached to face.

Next, the operation of the automatic stop of the machine by the detection plate 8 and the light sensor 10 will be described. In the present invention, the energization of spot welding is performed only when a specified pressing force acts on the nut 11 and the position of the lower end of the electrode tip 1 is at a predetermined position (only when the nut is normally supplied). Will be Therefore, when the nut is missing, that is, when the nut is not supplied, or when the nut is misaligned and supplied in the opposite direction, the position of the lower end of the electrode chip 1 is changed by the detection plate 8 and the light sensor 10. Since it is determined that the spot welding machine is not at the predetermined position, the spot welding machine automatically stops, so that adaptation to an automated line can be performed.

[0010]

As can be understood from the above description, the automatic stop device for the misalignment or chipping of the projection nut according to the present invention can be mounted on the electrode holder 7 for holding the electrode tip 1 in addition to the conventional misalignment detecting chip. Is provided with the detection plate 8 and the light sensor 10 on the appropriate sensor mounting arm 9 of the spot welding machine, so that the position of the lower end of the electrode during welding is detected, and when the supply of the nut is not performed correctly, The spot welder can be stopped automatically.
Therefore, misalignment of the nut, reverse orientation, chipping of the nut,
Defective products due to misalignment of the nut and the back-facing nut can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of an automatic stop device according to the present invention when a projection nut is misaligned or chipped.

FIG. 2 is a partial longitudinal sectional view of a conventional misalignment detection chip.

[Explanation of symbols]

1 electrode tip, 2 bottomed cylindrical body, 3 insertion hole, 4 O-ring, 5 insulating member, 6 misalignment detection chip, 7 electrode holder, 8 detection plate,
9 Sensor mounting arm,

Claims (1)

[Claims] An insertion hole (3) for inserting an upper half of a nut (11) into a lower surface of a bottomed cylindrical body (2) at a lower end of an electrode tip (1).
And an O-ring 4 for gripping the electrode tip 1 on the inner surface of the cylindrical body 2 and a misalignment detecting chip 6 with an insulating member 5 attached to the inner surface and lower end of the cylindrical body.
On the other hand, a detection plate 8 is provided via an appropriate frame on an electrode holder 7 which holds the electrode chip 1 and moves up and down by an air cylinder or the like. Further, a sensor mounting arm 9 is provided on an appropriate frame of the spot welding machine. And a light sensor 10 is provided at the tip of the sensor mounting arm 9 so as to face the detection plate 8.
Then, it detects the misalignment of the nut and the supply state in the opposite direction,
In the light sensor 10, in addition to the above-described nut supply state, the nut is chipped, and the machine can be stopped when the nut is supplied in a vertical direction. apparatus.