Electric heating – Metal heating – For bonding with pressure
Patent
1998-05-29
2000-12-19
Ryan, Patrick
Electric heating
Metal heating
For bonding with pressure
219148, B23K 928, B23K 1100
Patent
active
061630047
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to welding of projection nut after matching with a guide pin of a fixed electrode by moving a feed rod back and forth.
BACKGROUND ART
As known hitherto, a feed rod is forwarded from a direction nearly orthogonal to the axial line of an electrode, when a projection nut held in the feed rod comes just above a guide pin, the held projection nut is released and dropped into the guide pin. Such an example is disclosed in Japanese Laid-open Patent No. 51-109247. The disclosed art is as shown in FIG. 10, in which a hollow feed rod 1 is disposed so as to move back and forth nearly in the horizontal direction, and a box type part container 2 is formed at the leading end thereof Since the lower side of the part container 2 is open, a sliding plate 3 is placed, and the sliding motion is effected by a reciprocating rod 4. A steel plate part 6 is mounted on an electrode 5, and a guide pin 7 of the electrode 5 projects upward while penetrating through the steel plate part 6. The part is a projection nut indicated by reference numeral 8. The other electrode making a pair with the electrode 5 is omitted in the drawing.
FIG. 10 shows the projection nut 8 being supplied on the steel plate part 6 as indicated by solid line as the feed rod 1 moves forward, and the operation is described below. The feed rod 1 moves forward from a direction nearly orthogonal to the electrode 5, and when the nut 8 indicated by twin dot chain line comes to be coaxial with the guide pin 7, the feed rod 1 stops, and then the reciprocating rod 4 is moved back, and the lower side of the part container 2 is opened, so that the nut 8 drops, with the guide pin 7 driven into the screw hole as indicated by solid line, thereby finishing the feed of the nut. Then, the other electrode moves forward, and projection welding is completed.
In such prior art, since the projection nut 8 is dropped onto the guide pin 7, if the nut 8 is inclined in the transient period of fall, it may be repelled by the end of the guide pin 7, and may not be placed correctly as indicated by the solid line. Such an abnormal phenomenon may also occur if the feed rod 1 does not stop at a correct position due to a relative configuration with the guide pin 7. Moreover, the projection nut may be deviated in the rotating direction from the guide pin 7, and may not be welded in a uniform direction on the steel plate part 6.
BRIEF DESCRIPTION OF THE INVENTION
In one aspect of the invention, a welding apparatus of a projection nut is characterized by setting the forward and backward direction of a feed rod in a direction nearly orthogonal to an axial line of an electrode, forming a recess for holding a projection nut opened at the leading end of the feed rod, placing holding means of a projection nut in this recess, and placing a guide pin to advance into a screw hole of the projection nut stopped at a position nearly coaxial with the electrode in a state free to move in and out of the electrode. When the projection nut and guide pin are stopped nearly at coaxial positions, the guide pin advances to get into the screw hole of the nut, and when the feed rod moves back, the nut is released from the holding means and remains on the guide pin, and later the other electrode operates to complete projection welding. According to the invention, as the projection nut is held by the holding means in the recess of the feed rod, the guide pin of the advancing electrode gets into the screw hole in the projection nut, and then the feed rod moves backward, and therefore the projection nut is prohibited from moving an in abnormal direction both in the recess and by the guide pin, so that the problem of deviation of position of the nut due to a fall as in the prior art can be solved securely. Therefore, it is possible to weld whether the axial line of the electrode is in the vertical direction or horizontal direction.
In the bottom plate of the recess, a notch groove for passing the guide pin may be opened and formed at the leading end side of the feed rod.
REFERENCES:
patent: 2905803 (1959-09-01), Brady
patent: 5705784 (1998-01-01), Aoyama et al.
Aoyama Shoji
Aoyama Yoshitaka
Dey Anjan
Ryan Patrick
Yoshitaka Aoyama
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