Small- to medium sized injection molding machine with exceptional access to dies when open

摘要

The injection molding machine has a toggle joint arrangement actuated by hydraulic cylinders for closure, with swinging connection rods accepting closure forces when axi-parallel, permitting lightweight machine frame construction. A flexurally-rigid machine frame (6.1) for the die height adjuster (6) is fixed to the machine frame (2). The other side is connected to the injection-side die platen (4). Equipment opening and closing die halves include the two long connecting rods (7), short levers (8) and two hydraulic cylinders (9). The long rods are linked to the frame (6.1) at one end and at the other to the short levers (8). Each short lever is connected at its other end, centrally to the remote platen (3). Each short lever has two other pivots (8.4) below the molding axis, connected to hydraulic cylinders mounted on the machine frame. Preferred Features: The die height adjuster includes 1, 2 or 4 hydraulic cylinders moving the platen, fed with hydraulic fluid at up to the pump working pressure. The high pressure cylinders (6.2) are designed for pressure well over that of the pump. The sum of the piston areas in all cylinders is sufficiently small that the high pressure is sufficient to resist the maximum closure force. Cylinders have block valves which are closed during die closure, holding and reopening. Blocking is suspended briefly just before opening. During each cycle, with the dies partly or completely opened, the tool height is reset. There are adjustable pressure limiting valves on the piston side of the tool height adjustment cylinders. Each small lever (8) is a trapezoidal frame. Its four corners accept the closure forces from the linkage.