Abstract:
A welding apparatus is presented that allows for a controlled welding of steel cord ends. The welding apparatus allows for a controlled welding path from welding period over post-weld period to complete cool-down. In the welding apparatus a direct current source is controlled over time by means of a programmable controller. By sensing the voltage over the clamps of the welding apparatus and using this as a further input to the programmable controller, a constant power dissipation between the clamps can be achieved in the post-weld period. An associated method for making the weld is described wherein during the post-welding period the electric power dissipated between the clamps is held constant. The welds obtained by this procedure have a favourable metallographic structure in that the heat affected zone has more than 50% of pearlite and/or bainite over the total area of that zone.
Abstract:
An apparatus (100, 200, 300) and a method for measuring residual torsions of an elongated structure (202) such as a steel cord use a pivot head (102). The pivot head (102) comprises a wheel (104) adapted to guide an elongated structure (202). The wheel (104) is mounted in the pivot head (102) to transmit torques exercised by the elongated structure (202) on the wheel (104) to the pivot head (102). The pivot head (102) is mounted along a pivotal axis (110). This pivotal axis (110) lies in a plane of the wheel (104) and comprises the centre of the wheel (104). Sensor means (116, 206) measure the torque on the pivot head (102). The pivotal movement of the pivot head (102) around the pivotal axis (110) is limited to an angle range of ±5°, preferably ±3° in order to reach an improved accuracy of the torque measurement.