Screw-driven lift rail for milling head - uses counter-weighted pulley sheave to suspend beam from which head is suspended

摘要

The weight-compensator is used on a milling machine with machining heads (15, 15a) traversing an horizontal elevator beam (5). The beam (5) is mounted on a portal frame (3, 10, 3a), its vertical movement guided by a column (3, 3a) with integral tracks (6), and its drive provided by motorised screws (7) enmeshing with the beam (5) via integral nuts (8). Each head (15) is suspended from a second overhead beam (17) which is in turn suspended by a counterweighted (22) cable (21, 21a) and pulley (23, 24) system obviating unequal beam (5) reactions on the screws (7). The (15) suspension may use cantilever arms (18) to locate rollers (19) on tracks (20), and the weight of the counterweight (22) may equal that of the heads (15) and the second beam (17).