Control equipment for an injection moulding machine

Claim 2

Control equipment for an injection-moulding machine having various moving elements and a plurality of hydraulic receivers for displacing such moving elements, such receivers having supply pasSages, such control equipment comprising in combination: a plurality of electrically operated distributors of the type incorporating control electromagnets, hydraulic pilot units and constriction means that are regulable under the action of the hydraulic pilot units acting as pressure-reducers and the displacement of which is a function of the strength of the current passed to the corresponding control electromagnet; means coupling each distributor to at least one corresponding hydraulic receiver; a pressure-compensating means for regulating the hydraulic flow through said distributors, irrespective of the pressure used; a pressurized hydraulic fluid supply and means connecting each of said distributors and said pressure compensating means in circuit with said supply; means for converting the position of the various moving elements of the machine and the pressure obtaining in the supply passages of the corresponding hydraulic receivers into electrical values; means for displaying the required predetermined conditions relating to the speed of displacement of the moving elements and to the pressure in the corresponding hydraulic receivers; and electronic apparatus for processing said electrical values and for producing control signals for the electromagnets of the various distributors as a function of said predetermined conditions; whereby to enable with close control variable speeds and pressures in said hydraulic receivers substantially irrespective of the hydraulic pressure used.

Claim 3

Control equipment for an injection moulding machine having a mould including closeable mould part, first hydraulic receiver means for closing said mould part, plasticizer means having a movable support and movable injection means associated therewith, second hydraulic receiver means for moving said support and therewith said plasticizer means into adjacency with said mould and third hydraulic receiver means for moving said injection means for injecting material from said plasticizer means into said mould, the control equipment comprising in combination: first, second and third electrically operated distributors of the type incorporating control electromagnets, hydraulic pilot units and constriction means that are regulable under the action of the hydraulic pilot units acting as pressure-reducers and the displacement of which is a function of the strength of the current passed to the corresponding control electromagnet; hydraulic supply and return lines individually coupling said first, second and third distributors at one side thereof to said first, second and third hydraulic receiver means, respectively; a pressurized hydraulic fluid supply coupled to the other side of said distributors; means including a pressure compensating valve coupled to said supply and also to said other side of said first, second and third distributors for regulating the hydraulic flow through said first, second and third distributors irrespective of the pressure used; first, second and third potentiometer means mechanically coupled to and adjustable in response to movement of said closeable mould, said movable support and said movable injection means, respectively, for converting the positions thereof to electrical values; first, second and third pressure transducer means connected to said hydraulic supply lines of said first, second and third hydraulic receiver means, respectively, for converting pressure signals to electrical values; means for displaying required predetermined conditions relating to the speed of displacement of said closeable mould part, support and injection means and to the pressure in the corresponding first, second and third hydraulic receivers; and electronic apparatus for processing said electrical values and for producing control signals for the electromagnets of each of said first, second and third distributors as a function of corresponding ones of said predetermined conditions; whereby hydraulic flow velocity and pressure responsible for Movement of said mould part, support and injection means is controlled and applied through three similar, separate and parallel paths, each including one said distributor, set of supply and return lines, pressure transducer means, hydraulic receiver means and potentiometer means.

Claim 4

Control equipment for an injection moulding machine having a mould including closeable mould part, first hydraulic receiver means for closing said mould part, plasticizer means having a movable support and movable injection means associated therewith, second hydraulic receiver means for moving said support and therewith said plasticizer means into adjacency with said mould and third hydraulic receiver means for moving said injection means for injecting material from said plasticizer means into said mould, the control equipment comprising in combination: first, second and third electrically operated distributors of the type incorporating control electromagnets, hydraulic pilot units and constriction means that are regulable under the action of the hydraulic pilot units acting as pressure-reducers and the displacement of which is a function of the strength of the current passed to the corresponding control electromagnet; hydraulic supply and return lines individually coupling said first, second and third distributors at one side thereof to said first, second and third hydraulic receiver means, respectively; a pressurized hydraulic fluid supply coupled to the other side of said distributors; means including a pressure compensating valve coupled to said supply and also to said other side of said first, second and third distributors for regulating the hydraulic flow through said first, second and third distributors irrespective of the pressure used; first, second and third potentiometer means mechanically coupled to and adjustable in response to movement of said closeable mould, said movable support and said movable injection means, respectively, for converting the positions thereof to electrical values; first, second and third pressure transducer means connected to said hydraulic supply lines of said first, second and third hydraulic receiver means, respectively, for converting pressure signals to electrical values; means for displaying required predetermined conditions relating to the speed of displacement of said closeable mould part, support and injection means and to the pressure in the corresponding first, second and third hydraulic receivers; and electronic apparatus for processing said electrical values and for producing control signals for the electromagnets of each of said first, second and third distributors as a function of corresponding ones of said predetermined conditions; whereby hydraulic flow velocity and pressure responsible for Movement of said mould part, support and injection means is controlled and applied through three similar, separate and parallel paths, each including one said distributor, set of supply and return lines, pressure transducer means, hydraulic receiver means and potentiometer means.

Claim 5

The control equipment of claim 2, in which the injection moulding machine has means for ejecting a workpiece from the mould and fourth hydraulic receiver means for actuating said workpiece ejection means, said machine further having in said plasticizer means a rotatable plasticizing screw and fifth hydraulic receiver means for rotating such screw, said control equipment further including a fourth electrically operated distributor similar in type to said first, second and third distributors and coupled on one side thereof through hydraulic lines to said fourth and fifth hydraulic receiver means, said fourth distributor being coupled on the other side thereof to said fluid supply and said means including said pressure compensating valve and in a manner similar to the corresponding connections of said first, second and third distributors, the control electromagnet of said fourth distributor being connected for receiving control signals from said electronic apparatus.

Claim 6

The control equipment of claim 3, in which said means including said pressure compensating valve further includes a safety valve.

Claim 7

The control equipment of claim 3, in which said means including said pressure compensating valve includes a pressure reducing valve, said control equipment further including storage means associated with said hydraulic fluid source, whereby several simultaneous and precisely controlled velocities of displacement of said hydraulic receiver means are obtainable despite variations in the pressure supply to each.

Claim 8

The control equipment of claim 3, including pressure amplifier means connected in the supply line between said first distributor and said first hydraulic receiver means for providing the final high pressure required for closing the mould, feed lines connecting said pressure amplifier means to the supply and return line interconnecting said third distributor and said third hydraulic receiving means associated with said ejection means, said first pressure transducer means associated with said first receiver means being connected between first distributor and said pressure amplifier means.