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AssigneeCincinnati Milacron Inc.
InventorRonald A. Hertzer
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An improved computer controlled hydraulic system for a conventional toggle-operated plastic injection molding machine comprising an injection assembly and a mold clamping assembly. The hydraulic system includes a first low volume pump and a second high volume pump connected between a reservoir of hydraulic fluid and a pressure and flow control manifold. The output of the pressure and flow control manifold is connected to an injection control manifold, in turn conected to and operating the instrumentalities of the injection assembly. The output of the pressure and flow control manifold is also connected to a clamping control manifold, in turn connected to and operating the cylinder of the clamping assembly. An isolation manifold is connected between the pressure and flow control manifold and the clamping control manifold. A third low volume pump is connected between the reservoir and the isolation manifold. The isolation manifold is also connected to the reservoir. When unactuated, the isolation manifold connects the output of the pressure and flow control manifold directly to the clamping control manifold and recirculates the third pump to reservoir, when the machine is to perform sequential cycles such as conventional injection molding or conventional coining. When actuated, the isolation manifold disconnects the clamping manifold from the pressure and flow control manifold and connects the third pump to the clamping control manifold, enabling the machine to perform a coining cycle with individual and simultaneous clamping and injection control, and precise and repeatable position and speed control of the coining step.
A hydraulic system for a toggle operated plastic injection molding machine having a hydraulically actuated injection assembly and a hydraulically actuated toggle operated mold clamping assembly, said hydraulic system comprising a reservoir for hydraulic fluid, a first pump being a low volume pump and a second pump being a high volume pump, each of said first and second pumps having an inlet and an outlet, said pump inlets being connected to said reservoir, means for controlling the pressure and flow of hydraulic fluid from said outlets of said first and second pumps, means to operate said hydraulically actuated injection assembly by said controlled hydraulic fluid from said first and second pumps, and means to operate said hydraulically actuated mold clamp assembly by said controlled hydraulic fluid from said first and second pumps for sequential operation of said injection assembly and said mold clamping assembly during simple injection molding and coining operations, a third pump being a low volume pump and having an inlet and an outlet, said inlet of said third pump being connected to said reservoir, said outlet of said third pump being normally connected to said reservoir, and means to isolate said clamp assembly operating means from said controlled hydraulic fluid from said first and second pumps and to connect said outlet of said third pump to said clamping assembly operating means whereby said injection assembly and said clamping assembly can be operated independently and simultaneously during a precision coining operation with precise and repeatable speed and position control of said clamping assembly.
A hydraulic system for a toggle operated plastic injection molding machine having a mold clamping assembly and an injection assembly, said mold clamping assembly comprising a fixed platen and a fixed mold part mounted thereon, a movable platen and a movable mold part mounted thereon, and a hydraulic cylinder-operated toggle mechanism to shift said movable platen and mold part between an open position and a final mold closed and clamped position, said mold parts defining a mold cavity when closed, said fixed mold part having a passage from said cavity to an opening in said fixed platen, said injection assembly comprising a cylindrical body terminating at one end in a nozzle, said nozzle being connectable to said passage in said fixed mold part, a hopper mounted on said cylindrical body, a supply of plastic material within said hopper, a screw rotatable and axially shiftable within said cylindrical body, a prime mover operatively connected to said screw to rotate said screw to plasticate said plastic material and accumulate a charge thereof adjacent said nozzle, a hydraulic cylinder to shift said screw axially to inject said charge through said passage in said fixed mold part to said mold cavity, said hydraulic system comprising a reservoir of hydraulic fluid, a first pump being a low volume pump and a second pump being a high volume pump, each of said first and second pumps having an inlet and an outlet, a pressure and flow control manifold means having an outlet, said inlets of said first and second pumps being connected to said reservoir, said outlets of said first and second pumps being connected to said pressure and flow control manifold means, said pressure and flow control manifold means controlling the pressure and flow of hydraulic fluid at its outlet, an injection control manifold means, said pressure and flow control manifold means outlet being connected to said injection control manifold means, said injection control manifold means being connected to said injection assembly cylinder to control the axial position of said screw, a clamping control manifold means, said clamping control manifold means being connected to said cylinder of said clamping assembly to shift said toggle mechanism and said movable platen and mold part, an isolation control manifold means, said outlet of said pressure and flow control manifold means being connected to said isolation manifold means, said isolation manifold means having an outlet connected to said clamping control manifold means, a third pump being a low volume pump and having an inlet connected to said reservoir and an outlet connected to said isolation manifold means, said isolation manifold means having a connection to said reservoir, said isolation manifold means having a normal state wherein it connects said outlet of said pressure and flow control manifold means to said clamping control manifold means and said third pump outlet to said reservoir, said isolation manifold means having an actuated state wherein it isolates said clamping control manifold means from said pressure and flow control manifold means outlet and connects said outlet of said third pump to said clamping control manifold, and a control system to control said pressure and flow control manifold means, said injection control manifold means, said clamping control manifold means and said isolation control manifold means, whereby with said isolation control manifold means in its normal state said injection assembly and clamping assembly can be actuated sequentially by said first and second pumps, said pressure and flow control manifold means and said injection control manifold means and by said first and second pumps, pressure and flow control manifold means and said clamping control manifold means, respectively, for simple conventional injection molding and coining operations, and whereby when said isolation manifold means is in its actuated state said injection assembly and said mold clamping assembly can be independently and simultaneously controlled by said first and second pumps, said pressure and flow control manifold means and said injection control manifold means and by said third pump and said clamping control manifold means, respectively for precision coining operations.
Dependencies are inferred from the claim text.