| 摘要 |
<p>The hose comprises two flexible portions (9, 11) connected respectively to the suction unit (6) and to the fume-conveyor element or hood (17), and a rectilinear portion (14) which is articulated (37, 38; 42, 47) to the suction unit (6) and the hood (17). The rectilinear portion (14) comprises two rigid tubes (16, 17) between which is disposed an extensible bellows-type tube (21). Rigid tubes (16, 17) are held co-axial by a pair of rectilinear guides (26, 27) fixed to one of the rigid tubes (16, 17) and slidably engaging on a pair of fixed slides (29) on the other rigid tubes (17). The two rigid tubes (16, 17) are, finally, connected by a tension spring the action of which is braked by two friction disks (33) disposed between the guides (26, 27) and the slides (29). <IMAGE> <IMAGE></p> |
