US 5,734,141 A · Apparatus for automatically replacing welding electrodes

Abstract

A double extractor and an electrode supply station are provided for automatically replacing electrodes in opposing jaws of a resistance welding machine. With coated sheet steels now used for car body structures, it is found that electrodes must be replaced more often. The automatic replacement system is programmed to replace electrodes when the welding machine is idle such as between the movement of car bodies or other structures moving on a conveyor. A double extractor has a first position for extracting top electrodes and a second position for extracting bottom electrodes. Both positions have a plurality of gripping fingers operated by a cam, which simultaneously twist and pull-off the electrodes from the jaw. After the jaw has been removed, the gripping fingers release the old electrode.

Claims17

Dependent claims

An apparatus for automatically replacing electrodes from jaws of a resistance welding machine comprising:

(a) a double extractor having a first retaining position to retain electrodes from a first jaw of the welding machine and a second retaining position on the opposite side of the extractor to retain electrodes from a second jaw of the welding machine, each retaining position having a plurality of gripping fingers to grip an electrode;
(b) driving means for moving the gripping fingers inwards to grip an electrode and move the electrode away from the jaw to separate the electrode from the jaw;
and
(c) a cam engaging the gripping fingers relative movement between the cam and the gripping fingers causing movement of the gripping fingers inwardly and away from the jaws to separate the electrode from the jaws.

1 more element

A process for automatically replacing electrodes on opposing jaws of a resistance welding machine comprising the steps of:

moving a first jaw having a first electrode thereon and a second jaw having a second electrode thereon to a first extraction position,
lowering the first jaw with the first electrode thereon down into the first extraction position;
causing a cam to engage gripping fingers such that relative movement between the cam and the gripping fingers results in movement of the gripping fingers inwardly and away from the first jaw and thereby gripping the first electrode and turning the first electrode while pulling the first electrode away from the first jaw to separate the first electrode from the first jaw;
moving the first jaw and the second jaw back from the first extraction position and to a first electrode replacement position;
lowering the first jaw down to engage a first replacement electrode;
closing the first jaw and the second jaw so the first replacement electrode is pressed onto the first jaw;
moving the first jaw and the second jaw back from the first electrode replacement position and to a second extraction position;
raising the second jaw with the second electrode therein upwards into the second extraction position;
gripping the second electrode and turning the second electrode while pulling the second electrode away from the second jaw to separate the second electrode from the second jaw;
moving the first jaw and the second jaw back from the second extraction position and to a second replacement position;
raising the second jaw upwards to engage a second replacement electrode;
closing the first jaw and the second jaw so the second replacement electrode is pressed onto the second jaw;
and
moving the first jaw and the second jaw back from the second replacement position.

11 more elements

Dependencies are inferred from the claim text.

Apparatus for automatically replacing welding electrodes

Life of this patent

Apparatus for automatically replacing welding electrodes

Life of this patent

Abstract

Claims17