Electric heating – Metal heating – For bonding with pressure
Patent
1990-11-19
1992-05-05
Evans, Geoffrey S.
Electric heating
Metal heating
For bonding with pressure
219116, B23K 1110
Patent
active
051110199
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to the construction of a spot welding gun assembly which is to be mounted on the robot wrist of a multi-articulated robot used for welding (hereinafter referred to as "welding robot") for carrying out spot-welding of a workpiece or a work. More particularly, the invention relates to a variable-pitch spot welding gun assembly for the welding robot, which assembly is provided with two spot welding guns, a sliding mechanism capable of varying the position of one of the two spot welding guns relative to the other, to thereby change a pitch therebetween, and welding transformers for supplying an electric current to the two spot welding guns, respectively, which are fixedly arranged at positions as near as possible to the robot wrist.
BACKGROUND ART
Welding robots are widely used in a mass-production line for the spot-welding of, for example, automobile bodies, as workpieces The appearance and performance of the robot unit of such a welding robot is described in, for example, a catalog published by Fanuc Ltd. (Head office: Yamanashi-ken Japan) "FANUC ROBOT S Series", p. 14, Oct, 1989. A spot welding robot incorporated into such a mass-production line produces a spot-welding energy by transforming an electric primary voltage into a secondary voltage through an electric transformer, and applying the secondary voltage across the electrodes of the spot welding gun. Since the transformer is very heavy, in general practice the electric transformer is installed outside the framework of the welding robot, i.e., a robot unit, and only the spot welding gun is mounted on the robot wrist in such a manner that the secondary voltage of the transformer is supplied to the spot welding gun through a secondary welding cable extended between the transformer and the robot unit.
Nevertheless, since the secondary welding cable is extended between the spot welding gun mounted on the robot wrist and the transformer installed apart from the robot unit, and because the welding cable used must be a heavy cable, due to a large current capacity thereof, the movement of the movable components of the robot unit such as the robot arm or the robot wrist, is obstructed by the welding cable if the robot body portion or the robot arm of the robot unit becomes entwined with the welding cable.
An improvement has been made, in an attempt to solve the problems attributable to the entwinement of the movable robot components with the welding cable, in which the transformer is disposed at a particular position on the robot unit, such as near the extremity of the robot wrist. Nevertheless, there is a need for an improvement of the production efficiency of the welding process in the mass-production line, through the curtailment of the processing time to the least possible extent by mounting two spot welding guns on a single welding robot to form a plurality of weld spots in a single spot-welding cycle.
When the two spot welding guns, each provided with an electric transformer are mounted on the robot wrist or a part in the vicinity of the robot wrist, however, the gravitational load on the robot wrist and other movable robot components is greatly increased, and accordingly, the robot unit becomes unable to fully exhibit its functions and the entire robot performance is restricted.
DISCLOSURE OF THE INVENTION
Accordingly, an object of the present invention is to provide a variable-pitch spot welding gun assembly for a welding robot, which enables a full utilization of a degree or degrees of freedom of motion of the welding robot and is provided with two spot welding guns supported so as to be movable toward and away from each other, to thereby curtail the time necessary for the spot welding process, and thus improve the efficiency of the spot welding process.
In the present invention, when two spot welding guns are mounted on the robot wrist of a welding robot, electric transformers for supplying electric power to the respective spot welding guns are separated from the spot welding guns and are attached t
REFERENCES:
patent: 1189584 (1916-07-01), Kicklighter
patent: 1434374 (1922-11-01), Lemon et al.
patent: 4291214 (1981-09-01), Arthurs et al.
patent: 4496821 (1985-01-01), Burgher et al.
patent: 4559438 (1985-12-01), Nakadate et al.
"Articulated Type Industrial Robots for Various Application", Fanuc Robot S Series, RS-17, 10/1989.
Naito Yasuo
Torii Nobutoshi
Ueda Kunio
Evans Geoffrey S.
Fanuc Ltd.
LandOfFree
Variable-pitch spot welding gun assembly for a welding robot does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Variable-pitch spot welding gun assembly for a welding robot, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable-pitch spot welding gun assembly for a welding robot will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1413937