| 摘要 |
Four trains of gripping element quadrants are advanced continuously around four endless paths, meeting along one length of travel common to the four paths and cooperating to form a succession of centrally apertured gripping elements moving continuously toward an extrusion die located along the common length of travel. The gripping element quadrants are driven by pinion gears, each of which engages simultaneously sets of teeth on gripping element quadrants in two adjacent trains in order to key the quadrants together and thereby prevent one quadrant from lagging another during their advance toward the die. Four guide elements extend along the paths of the gripping elements and engage simultaneously portions of the two adjacent gripping element quadrants to guide the engaged quadrants during their advance toward the die. Four endless belts are advanced with the gripping elements toward the die and serve to transmit pressure from four stationary pressure pads to the moving gripping elements. Rod of indefinite length, coated with a shear transmitting medium and extending into the central apertures of the gripping elements, is drawn along the common length of travel by means of shear forces generated in the coating by the gripping elements and transmitted to the rod as viscous drag force along the surface of the rod. Axial and normal stresses are built up in the rod to stress the rod far above its yield strength and increase its ductility, or capacity for deformation without fracture. In this state, the rod is moved through and deformed by the die. |
