| 摘要 |
<p>A car bumper is assembled by welding together a channel-shaped facing component (4) and a rigid backing component (15), of mutually compatible thermoplastics, using sacrificial heating elements (17) to soften the surface portions to be welded while the components are held in jigs. Once these portions have been softened, but not until then, pressure is applied to force the softened portions together, by means of movable members (9,10) coextensive with the seams and moved by inflation of resilient tubes (11,12) carried in recesses in the jig (5) which supports the facing component. After the weld surfaces have thus become fused, they are allowed to cool.</p> |
