US3904078A
Expired / Lapsed
US
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Injection molding machine having a programming device and a method of operating the machine
Assignee: Netstal Maschinen AG
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Filing: 1974-01-18
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Granted: 1975-09-09
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Expires: 1994-01-18
Abstract
Abstract An injection molding machine, particularly for plastics, comprises an injection cylinder having an injection discharge at one end and an inlet for material to be plasticized which is spaced therefrom. An injection screw is rotatable in the cylinder and it is also movable by the force of a fluid pressure applied against a piston so that it will advance in the cylinder. A connection for supplying a pressure for operating the piston is connected to a control device which in turn is connected to means for measuring the pressure for actuating the piston and for also measuring the distance of movement of the injector screw and the velocity of its movement. The operating pressure for advancing the screw is continuously measured and the switching device which is connected to the control is operated so that upon reaching a predetermined hydraulic pressure and after a predetermined movement of the screw and a predetermined filling distance movement, the mold filling phase is carried out in which the injection velocity is controlled as a function of the covered distance and this control is switched over to an after pressure phase in which the after pressure is applied for a predetermined time control period on the basis of the operating pressure.
Inventors
- 👤 Engelbert Neff
- 👤 Jakob Fehr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:33
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/76; B29C45/77
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
223 words
An injection molding machine, particularly for plastics, comprising an injection cylinder having an injection discharge and an inlet for material to be plasticized spaced therefrom, an injector screw rotatable in said cylinder, means to rotate said injector screw, a pressure cylinder, a piston connected to said screw and being movable in said cylinder to advance said screw, pressure means for supplying fluid pressure to said pressure cylinder to advance said piston, pressure measuring means for measuring the pressure in said cylinder to advance said piston connected to said cylinder, velocity measuring means connected to said screw for measuring the velocity of movement thereof, distance measuring means connected to said screw for measuring distance moved by said screw in operation, a control unit connected to said pressure means for controlling the fluid pressure of said pressure cylinder, and a switching device connected to said control unit to said pressure means and to said pressure measuring means and said velocity measuring means, effective during operation of said screw and upon the reaching of a predetermined pressure in said cylinder and not later than after the screw has moved in a predetermined distance to eject the plastic material, to regulate said pressure means in accordance with the covered distance and thereafter to cause said pressure means to apply an after pressure for a period of time.
Claim 2
Dependent Claim
223 words
An injection molding machine, particularly for plastics, comprising an injection cylinder having an injection discharge and an inlet for material to be plasticized spaced therefrom, an injector screw rotatable in said cylinder, means to rotate said injector screw, a pressure cylinder, a piston connected to said screw and being movable in said cylinder to advance said screw, pressure means for supplying fluid pressure to said pressure cylinder to advance said piston, pressure measuring means for measuring the pressure in said cylinder to advance said piston connected to said cylinder, velocity measuring means connected to said screw for measuring the velocity of movement thereof, distance measuring means connected to said screw for measuring distance moved by said screw in operation, a control unit connected to said pressure means for controlling the fluid pressure of said pressure cylinder, and a switching device connected to said control unit to said pressure means and to said pressure measuring means and said velocity measuring means, effective during operation of said screw and upon the reaching of a predetermined pressure in said cylinder and not later than after the screw has moved in a predetermined distance to eject the plastic material, to regulate said pressure means in accordance with the covered distance and thereafter to cause said pressure means to apply an after pressure for a period of time.
Claim 3
Dependent Claim
84 words
An injection molding machine, according to claim 1, wherein said pressure measuring means comprises a pressure gauge exposed to the pressure in said cylinder behind said piston, said velocity measuring means comprising a movable member adapted to produce an electrical signal in response to the velocity of movement of said screw, a switching device connected to said pressure gauge and said velocity measuring means and to said control, said control being connected to said pressure means to regulate the pressure supplied behind said piston.
Claim 4
Dependent Claim
35 words
An injection molding machine, according to claim 2, wherein said pressure means comprises a pressure source and a servo valve operated by said control for regulating the connection of said pressure source to said cylinder.
Claim 5
Dependent Claim
52 words
An injection molding machine, according to claim 2, wherein said distance measuring means comprises an instrument generating an electric signal in proportion to the movement distance of said injector screw, a monitoring logic connected to said distance measuring means and to said switching device and a timer connected to said monitoring logic.
Claim 6
Dependent Claim
21 words
An injection molding machine, according to claim 4, including a programmer connected to said monitoring logic and to said control unit.
Claim 7
Dependent Claim
92 words
An injection molding machine, according to claim 1, wherein said pressure cylinder comprises a cylinder arranged alongside one end of said injector cylinder, said injector screw including a rib portion extending into said pressure cylinder, said piston surrounding said rear portion of said injector screw and being affixed thereto for rotation and movement therewith, a non-rotatable plate connected to said rear portion of said injector screw, said distance measuring means comprising a rack carried on said plate, and a gear rotated by said rack upon movement thereof and generating an electrical signal.
Claim 8
Independent Claim
158 words
A method of operating an injection molding machine for molding plastics which includes an injection screw rotatably and axially displaceably mounted in an injection cylinder having a discharge, means for rotating said injector screw and a pressure piston connected to the screw and being movable by hydraulic pressure to displace said screw, comprising supplying a pressure to said piston to displace said screw during the injection process and continuously measuring the pressure applied to the screw, and upon rEaching a predetermined pressure by not later than after the screw has covered a predetermined distance supplying a plastic for filling a mold during a mold filling phase of operation, wherein the movement of the injector is controlled as a function of the covered distance of movement by the injector screw, and thereafter, carrying out a pressure phase in which an after pressure is applied to the injector screw on a time controlled basis in proportion to the pressure applied.
Claim 9
Independent Claim
158 words
A method of operating an injection molding machine for molding plastics which includes an injection screw rotatably and axially displaceably mounted in an injection cylinder having a discharge, means for rotating said injector screw and a pressure piston connected to the screw and being movable by hydraulic pressure to displace said screw, comprising supplying a pressure to said piston to displace said screw during the injection process and continuously measuring the pressure applied to the screw, and upon rEaching a predetermined pressure by not later than after the screw has covered a predetermined distance supplying a plastic for filling a mold during a mold filling phase of operation, wherein the movement of the injector is controlled as a function of the covered distance of movement by the injector screw, and thereafter, carrying out a pressure phase in which an after pressure is applied to the injector screw on a time controlled basis in proportion to the pressure applied.
Claim 10
Dependent Claim
165 words
An injection molding machine for plastics, comprising an injection cylinder having a discharge, a hydraulically operated plasticizing and injection screw longitudinally movable in said injection cylinder and a program unit having means for controlling the hydraulic pressure acting to move said screw through a control device, a device for continuous measuring of the hydraulic pressure, a timer, means continuously measuring the velocity of the movement of the screw, means continuously measuring the distance moved by said screw and a switching device by which, during a first mold filling phase terminated by reaching a predetermined hydraulic pressure but not later than after the screw has covered a predetermined portion of the filling distance, begins a second mold filling phase in which the said velocity is controlled as a function of the covered movement, said switching device being thereafter switched over to a third after pressure phase in which the after pressure is time controlled on the basis of a hydraulic pressure higher than said petermined pressure.
Claim 11
Dependent Claim
165 words
An injection molding machine for plastics, comprising an injection cylinder having a discharge, a hydraulically operated plasticizing and injection screw longitudinally movable in said injection cylinder and a program unit having means for controlling the hydraulic pressure acting to move said screw through a control device, a device for continuous measuring of the hydraulic pressure, a timer, means continuously measuring the velocity of the movement of the screw, means continuously measuring the distance moved by said screw and a switching device by which, during a first mold filling phase terminated by reaching a predetermined hydraulic pressure but not later than after the screw has covered a predetermined portion of the filling distance, begins a second mold filling phase in which the said velocity is controlled as a function of the covered movement, said switching device being thereafter switched over to a third after pressure phase in which the after pressure is time controlled on the basis of a hydraulic pressure higher than said petermined pressure.
Claim 12
Dependent Claim
104 words
An injection molding machine for plastics, according to claim 8, wherein the output of the device for measuring the hydraulic pressure and the output of a device for measuring the injection velocity are connected to a selecting device associated with a monitoring logic which is connected to the outputs of the screw advance measuring device and of the timer and cooperates both with the machine control and an adjustable program unit which, for transmitting set value signals of the injection velocity and the hydraulic pressure, is connected to a control unit acting on the hydraulic pressure in the injection cylinder through a servo valve.
Claim 13
Dependent Claim
24 words
An injection molding machine for plastics, according to claim 9, wherein the monitoring logic and the program unit are designed as all electronic units.
References Cited (Backward Citations)
US3642404A
Cited
US3797808A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-08 | 1979-03-10 | 1979-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-08 | 1983-03-10 | 1983-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-08 | 1987-03-10 | 1987-09-09 | $7700.00 | Window Closed / Lapsed |