GB1151353A - Improvements relating to Electrical Resistance Welding Apparatus - Google Patents

Abstract

1,151,353. Welding by pressure. ROLLSROYCE Ltd. 1 July, 1966 [2 July, 1965], No. 28163/65. Heading B3R. Resistance welding apparatus comprises means for pressing together a pair of workpiece parts, the means including a member which has a surface for pressing on one of the parts, the member having a hole extending through it from a position at or adjacent to the surface, and the apparatus further comprises a sensing means to sense radiation passing along the hole from the said position to provide information as to the effectiveness of the weld. A resistance welding machine has a pair of rod-shaped electrodes 1, 2 with circular end faces 3, 4 engaging sheet metal components 5, 6, the copper electrode 2 having a hole 8 at one end opening in the face 4 and extending right through the electrode to be open to an infra-red sensing device 9. The device 9 is connected to a means for giving a signal if the temperature of the workpiece is too hot or too cold. The output of the sensor may be used to provide a signal for automatically varying the welding current and/or duration of the current. The setting of the machine may be varied during the making of the welding if the weld is too cold. The hole need not break through the surface 4 when the heat sensed is that at the tip of the electrode. In a modification, the end of the electrode remote from the working end is threaded into a metal block having inlet and outlet passages and copper sleeves extending into the bore of the electrode. A photo-electric cell is carried at the far end of the bore and the electrode is cooled by water fed through the passages and around the sleeves and the cell may be included in a control system as described above. Alternatively, the sensor is focused through a mirror on to the point on the component. Both electrodes may be associated with heat sensors.