| 摘要 |
The present invention relates to a contact tube for gas-shielded-arc welding in order to guide the welding wire and transfer the current from the contact tube to the welding wire, which is realised in a known manner by a contact tube in which the guide bore is 0.2 mm larger than the wire to be welded. The wire therefore has no exact guidance, and the discharge direction of the wire from the contact tube changes. The poor bearing of the wire against the wall of the bore leads to an undefined current transfer. The result of this is that the striking characteristic is considerably impaired and the life of the contact tube is reduced. In order to remove these shortcomings, the invention proposes to fit a pressure mechanism into the contact tube, which pressure mechanism presses the welding wire over an optimum section against the current-carrying bore wall of the contact tube so that a defined current transfer, exact striking of the arc and effective guidance of the welding wire are achieved.
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