Bar cropping shears of four-crank type - have throw of cutting crankshaft smaller than throw of auxiliary crankshaft to raise mechanical advantage

摘要

The bar stack (16) is fed from the straightener (13) into the pair of shears (11,12) where it is cropped into commercial lengths. The upper blade (11) is mounted in a carrier (9), which is connected to a cutting crankshaft (5) by a link (19) and to an auxiliary crankshaft (8). The throw (22) of the auxiliary crankshaft is less than the length (21) of the link (19). The throw (20) of the cutting crankshaft is less than that of the auxiliary crankshaft. The lower blade (12) is carried in a similar linkage and works together with the upper blade through the action of synchronising gears (7,18). The linkage configuartion traverses the blades through a path (24) whose horizontal component is determined by the auxiliary crankshaft (8). The small vertical cutting crankshaft (5,6). USE/ADVANTAGE - Greater mechanical advantage reduces size of motor required.