| 摘要 |
<p>A fume-extracting welding gun has an internal fume-extracting passage and comprises a handle member and a head member which have a normally-fixed angular position but which can be adjusted to another selected angular position. The head member has variable dimension passageways therethrough to the fume-extracting passageway to enable the vacuum applied at the welding site by the fume-extracting passageway to be varied by varying the flow of air through the passageways. The passageways are provided by openings in overlapping portions of a sleeve member and the head member and rotation of the sleeve member varies the passageway dimension.</p> |
