Stroke control for toggle press drive - has crankshaft driven eccentric cam drive acting through clutch to collapse toggle and disengage drive

摘要

The press or shear has the tool slide drive (5) derived from a four-bar chain having a toggle (3, 4) which is collapsible about a hinge (16). If an upwards force is exerted on the hinge, the toggle is held straight and the drive motion is transmitted. If the hinge is broken by a downwards force, the crankshaft continues to rotate but the tool slide motion is immediately arrested. An upwards force to maintain the drive is exerted by a spring (17) through a hanger (15). The top end of the hanger is connected by an arm (14) to half (13) of a magnetic clutch (12). This is disengaged to keep the toggle straight and the slide moving to and fro. When the clutch is engaged the half (11), which is kept in oscillating motion by the crankshaft eccentric cam drive (6 to 10) causes the arm (14) to drive the hanger downwards against the spring force and 'break' the connecting rod hinge. The drive is restored by disengaging the clutch. ADVANTAGE - Eliminates manual effort.