FR3076482A1 - SYSTEM FOR CONTROLLING A SHUTTER OF A PLASTIC MATERIAL INJECTION SYSTEM - Google Patents

Abstract

The invention relates to a control system for a shutter slidably arranged in a plastic injection nozzle, comprising: an electric motor coupled to said shutter for slidingly driving it between a closed position of the nozzle and a maximum opening position of the nozzle, - a device (2) for controlling the motor, comprising at least two components integrated in an electronic control card of the engine, said components being chosen from: * a component adapted to regulate the race of the shutter at a first constant speed, * a component adapted to regulate the shutter stroke at a second constant speed, greater than the first speed, * a component adapted to selectively block the shutter stroke, - a sequential control unit comprising at least two control channels (30, 31, 32), configured to selectively send an electrical comma signal nde the device (2) by one and / or the other of said control channels (30, 31, 32) so that: - under the effect of a first signal sent by the first control channel ( 30), one of the components is activated, - under the effect of a second signal sent by the second control channel (31), another component is activated Figure for the abstract: Fig 1A

Description

Description

Title of the invention: CONTROL SYSTEM FOR A SHUTTER OF A MATERIAL INJECTION SYSTEM

PLASTIC

Technical Field [0001] The present invention relates to a control system for a shutter arranged to slide in a plastic injection nozzle.

BACKGROUND OF THE INVENTION

An injection system of the “hot block” or “hot runner” type (“hot runner” according to English terminology) usually comprises: [0003] - a distributor delimiting a plastic distribution channel and comprising an outlet for thermoplastic material, said distributor comprising means making it possible to maintain its temperature, and consequently that of the material passing through the distribution channel, at a temperature above the limit temperature for passage of the material to the fluid state .

[0004] an injection nozzle defining at least a portion of a transit passage, the inlet of which is in fluid connection with the outlet of the distribution channel, and the outlet of which opens out substantially into the molding footprint, [ 0005] - a shutter mounted with longitudinal sliding inside the transit passage and occupying alternately a closed position and an open position thereof, [0006] - control means for alternately sliding the shutter between the shutter position and the open position.

The control of the opening and closing of the shutter is of particular importance for the quality of the parts formed in the molding impression, in particular in the case of a sequential injection, that is to say say when the molding imprint is supplied by several injection nozzles whose opening and closing are offset in time.

In particular, it is desirable to be able to vary over time the sliding speed of the shutter.

Depending on the technology used to control the shutter (pneumatic, hydraulic or electric), different solutions have already been implemented to vary the sliding speed of the shutter.

[0010] Thus, document EP 2 679 374 describes a control system for a shutter comprising an electric motor coupled to said shutter by a transmission mechanism adapted to transform a rotational movement of the engine into a sliding movement of the shutter. . The motor control makes it possible to control the sliding speed of the shutter.

Document EP 2 604 408 describes a control system for a shutter comprising a hydraulic cylinder coupled to said shutter to cause it to slide and a hydraulic circuit for controlling the cylinder comprising a bidirectional solenoid valve for injecting or to remove a fluid from the cylinder to actuate the shutter in one direction or the other. The hydraulic circuit also includes, in series with the bidirectional solenoid valve, a proportional control flow regulator controlled by a control unit. Depending on the signal transmitted by the control unit, the regulator allows a greater or lesser flow of fluid. Therefore, by adjusting the regulator flow, it is possible to vary over time the sliding speed of the shutter in the nozzle.

However, the control systems mentioned above are relatively expensive and complex.

BRIEF DESCRIPTION OF THE INVENTION

An object of the invention is to design a control system for a shutter making it possible to modulate the speed of the shutter - or even to block its travel - which is simpler and less expensive than existing systems, and this, regardless of the type of cylinder (hydraulic, pneumatic or electric) used to actuate the shutter.

According to the invention, there is provided a control system for a shutter arranged to slide in a plastic injection nozzle, comprising: [0015] - a jack coupled to said shutter to cause it to slide between a closed position of the nozzle and a maximum open position of the nozzle, - an actuator control device, comprising at least two elements among: • an element adapted to regulate the stroke of the actuator to a first constant speed, • an element adapted to regulate the stroke of the jack at a second constant speed, greater than the first speed, • an element adapted to selectively block the stroke of the jack, [0017] - a sequential control unit comprising at least two control channels configured to selectively send an electrical control signal to the device by one and / or the other of said control channels so that: - under the effect of a first signal sent by the first control channel, one of the elements is activated, - under the effect of a second signal sent by the second control channel, another item is activated.

According to one embodiment, the actuator is a hydraulic or pneumatic actuator and the actuator control device comprises: - a fluid distribution device to the actuator, comprising: • a first channel in fluid connection with a first cylinder chamber, • a second channel in fluid connection with a second cylinder chamber, • a third fluid supply channel from a reservoir, • a main solenoid valve arranged to selectively establish a fluid connection between the third channel and the first or second channel, • at least two elements chosen from: • a first unidirectional regulator of the fluid flow arranged in the fluid connection between the first channel and the first chamber of the jack, said first regulator being adjusted to a first flow constant, • a second unidirectional regulator of the fluid flow arranged in the fluid connection between the first vo ie and the first cylinder chamber in series or in parallel with the first regulator, said second regulator being adjusted to a second constant flow rate greater than the first flow rate, • a solenoid valve arranged so as to selectively block the circulation of fluid between the first channel and the first chamber of the jack, • at least two electrical control members adapted to move at least one mobile member so as to selectively establish at least two different configurations of the fluid circuit within the distribution device, said configurations being chosen so that 'during a nozzle opening cycle, the fluid passes successively through each of said at least two elements, - a sequential control unit comprising at least two control channels each electrically connected to a member electrical control of the distribution device, said control unit being configured to selectively send an electrical control signal by one and / or the other of said control channels so that: • under the effect of a first signal sent by a first control channel, the distribution device adopts a first configuration, • under the effect of a second signal sent by a second control channel, the distribution device adopts a second configuration different from the first.

According to one embodiment, said system further comprises at least one flow rectifier coupled to at least one unidirectional flow regulator.

Furthermore, the system further comprises a non-return valve arranged in parallel with at least one unidirectional flow regulator.

In a particularly advantageous manner, the system further comprises a solenoid valve arranged so as to selectively establish a fluid connection between the first chamber of the jack and the first or the second unidirectional flow regulator during an opening phase of the 'shutter.

Preferably, the flow of the first and / or the second regulator is adjustable within a determined flow range.

According to another embodiment of the invention, the cylinder is electric and the elements are electronic components integrated in an electronic card for controlling the cylinder.

In a particularly advantageous manner, the jack or the shutter is provided with a position sensor and the sequential control unit is configured to control the emission of the control signals as a function of the measurements supplied by said position sensor .

Optionally, the sequential control unit is configured to also take into account at least one of the following data: a time of the injection process, a position of a sensor, a pressure or a temperature in l injection tool, a signal from the injection press.

According to one embodiment, the sequential control unit is configured to send an electrical control signal in the form of direct current.

Alternatively, the sequential control unit is configured to send an electrical control signal in the form of alternating current.

BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages of the invention will emerge from the detailed description which follows, with reference to the attached drawings in which: [0033] [fig.l A] is a block diagram of a shutter control system according to one embodiment of the invention, [fig.lB] is a block diagram of a shutter control system according to another embodiment of the invention , [Fig.2] is a hydraulic diagram of a shutter control system according to an embodiment of the invention, [fig.3] is a hydraulic diagram of a system of shutter control according to another embodiment of the invention, [fig.4] is a curve of the stroke of the shutter as a function of time during two cycles of opening-closing of the shutter can be obtained with the embodiments of Figures 2 and 3, [fig.5] e st is a hydraulic diagram of a shutter control system according to another embodiment of the invention, [fig. 6] is a hydraulic diagram of a shutter control system according to another embodiment of the invention, [fig.7A] is a curve of the travel of the shutter as a function of time during an opening-closing cycle of the shutter capable of being obtained with the embodiment of Figure 5, [fig.7B] is a curve of the travel of the shutter as a function of time during an opening-closing cycle of the shutter capable of be obtained with the embodiment of FIG. 6.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In a manner known per se, the injection system comprises a shutter arranged to slide in a plastic injection nozzle.

In general, the shutter control system comprises a jack whose rod is coupled to said shutter to cause it to slide between a closed position of the nozzle and a maximum open position of the nozzle.

According to one embodiment, the cylinder is a hydraulic cylinder. Alternatively, the cylinder is a pneumatic cylinder. According to a third embodiment, the cylinder is electric.

In all cases, the shutter control system includes an actuator control device which includes at least two of the following three elements: - an element for regulating the speed of the actuator adjusted to a first constant speed, [0048] - an element for regulating the speed of the jack set to a second constant speed, greater than the first speed, [0049] - an element for blocking the opening stroke of the jack.

Depending on the type of cylinder, the speed of the cylinder (and therefore of the shutter) is adjusted by a fluid flow entering or leaving the cylinder (in the case of a hydraulic or pneumatic cylinder) or by an electrical signal emitted by a component of an electronic control card to a cylinder motor (in the case of an electric cylinder). Likewise, the blocking of the cylinder stroke can be obtained by blocking the circulation of fluid entering or leaving the cylinder (in the case of a hydraulic or pneumatic cylinder), or by a specific electrical signal emitted by a component d '' an electronic control card to a cylinder motor (in the case of an electric cylinder).

Advantageously, all of these three elements offer the greatest variety of combinations of speed / racing locks. However, in practice, the use of only two of these three elements is sufficient to provide a fine adjustment of the shutter stroke, capable of significantly improving the quality of the injected parts.

Whatever technology is selected, said elements are electrically controlled by a sequential control unit. Such a control unit, also known by the term sequencer, is available on the market according to different models and does not require any particular adaptation to be able to be used in the present invention.

The sequential control unit comprises at least two control channels, each electrically connected to one of the above-mentioned elements.

The sequential control unit is configured to selectively send an electrical control signal by one and / or the other of said control channels to the elements of the actuator control device such that: [0055] - under the effect of a first signal sent by the first channel, the actuator is moved at a first speed, [0056] - under the effect of a second signal sent by the second route, the actuator is moved at a second speed different from the first one or its race is blocked.

Each control signal can be transmitted in the form of a direct electric current or an alternating current.

In a particularly advantageous manner, the jack or the shutter is provided with a position sensor coupled to the sequential control unit and the sequential control unit controls the emission of the control signals according to the measurements provided. by said position sensor. The use of such a sensor is known in itself and does not need to be described in more detail in the present text. Generating the control signals from the measurement data of such a position sensor allows more precise control of the opening-closing sequence than from a purely temporal sequencing.

Furthermore, the sequential control unit can take into account at least one of the following data - combined (s) with the data from the above-mentioned position sensor - for the transmission of the control signals: a time, the position of a sensor (for example: the position of the extrusion screw), pressure or temperature in the tool (injection mold or hot block), a signal from the injection molding machine (for example: top injection, top maintenance), etc. These data are commonly recorded during the implementation of the thermoplastic injection process, and the injection molding machine and the injection tool are equipped with appropriate sensors, coupled to an acquisition unit. The exploitation of this data therefore does not require acquisition means developed specifically for the invention. A person skilled in the art is able to process one or more of said signals and to deduce therefrom a programming of each opening-closing sequence of the shutter.

Figure IA is a block diagram of the shutter control system according to one embodiment.

The cylinder is designated by the reference 1. The shutter is not shown in this figure. The actuator control device 2 comprises three elements 2A, 2B, 2C, one of which is an element for regulating the speed of the actuator adjusted to a first constant speed (called slow speed), another is an element for regulating the speed of the jack set at a second constant speed (called rapid speed), greater than the first speed, and yet another is an element for blocking the opening stroke of the jack. As will be seen below, there may be interactions between the elements 2A, 2B and 2C (in particular fluidic connections, in the case of the supply device for a hydraulic or pneumatic cylinder). However, these are not shown in Figure 1.

The sequential control unit is designated by the reference 3. It includes three output channels 30, 31, 32, each connected to a respective element 2A, 2B, 2C of the actuator control device, allowing it to be sent a respective control signal SI, S2, S3.

Figure IB is a block diagram of the shutter control system in a simplified embodiment in which the device 2 comprises only two elements 2A, 2B. In this case, only two channels 30, 31 of T sequential control unit 3 are used.

We are now more specifically interested in the case of a hydraulic or pneumatic cylinder.

The cylinder is a double-acting cylinder and therefore comprises a cylinder defining two chambers insulated Tune from the other by a piston capable of sliding in said cylinder and integral with the rod. Each of the two chambers includes a fluid inlet / outlet port. By convention, it is considered that the maximum opening stroke of the shutter is reached when the volume of fluid in the second chamber is maximum and the volume of fluid in the first chamber is minimum. Conversely, the shutter is in the closed position when the volume of fluid in the first chamber is maximum and the volume of fluid in the second chamber is minimum.

The actuator control device comprises a device for distributing fluid to the actuator (the fluid being a liquid in the case of a hydraulic actuator, a gas in the case of a pneumatic actuator).

This distribution device comprises: - a first channel in fluid connection with a first chamber of the cylinder, [0070] - a second channel in fluid connection with a second chamber of the cylinder, [0071] - a third channel fluid supply from a reservoir.

In the case of a hydraulic cylinder, the distribution device further comprises a fourth channel for the return of the fluid to the reservoir. In the case of a pneumatic cylinder, such a fourth channel is not necessary, the fluid leaving the cylinder being returned to the atmosphere.

Furthermore, the distribution device comprises one or two unidirectional regulators of the fluid flow and two or three solenoid valves arranged so as to selectively establish at least two different configurations of the fluid circuit within the distribution device, during '' a phase of opening and possibly closing the shutter.

Different embodiments of these solenoid valves and their arrangement in the fluid circuit will be described in detail with reference to Figures 2, 3, 5 and 6.

A first unidirectional regulator of the fluid flow is arranged in the fluid connection between the first channel and the first chamber of the jack. Said first regulator is regulated at a first constant flow rate.

A second unidirectional regulator of the fluid flow is arranged in the fluid connection, in series or in parallel with the first regulator, between the first channel and the first chamber of the jack. Said regulator is adjusted to a second constant flow greater than the first flow.

Although each of the two unidirectional flow regulators imposes a respective constant flow during an operating cycle of the shutter control system, it goes without saying that the flow of each of these shutters can be adjustable, for example by means of a wheel, in a given flow range. This optionally allows, between two plastic injection cycles, to modify the flow rate imposed by one and / or the other of said regulators. Such unidirectional regulators are available on the market in different models and do not require any special adaptation to be used in the present invention.

Furthermore, the solenoid valves comprise electrical control members (typically, electromagnetic coils) adapted to move at least one movable member (typically, a drawer comprising a plurality of through or blocking channels) so as to selectively establish at least two different configurations of the fluid circuit within the distribution device.

Each of the coils is electrically connected to one of the channels of the sequential control unit.

Each solenoid valve allows the selection of a particular modality of the fluid circuit.

Thus, a first solenoid valve, called the main solenoid valve, makes it possible to define the direction of circulation of the fluid within the dispensing device. Thus, a position of said solenoid valve makes it possible to circulate the fluid from the reservoir to the first chamber of the jack and to the second chamber of the jack (closing phase of the shutter), while another position of the solenoid valve allows circulate the fluid from the reservoir to the second chamber of the cylinder and from the first chamber of the cylinder to the reservoir (opening phase of the shutter). The main solenoid valve can thus be monostable. Optionally, said main solenoid valve can also have a neutral position, in which no fluid connection is established between the two chambers of the jack and the reservoir. In this case, the main solenoid valve is bistable.

A second solenoid valve makes it possible to select a slow or fast opening speed. To this end, said solenoid valve is selectively coupled - depending on the position of its drawer - to the first or second unidirectional flow regulator on the fluid path between the first chamber of the jack and the reservoir. Each unidirectional flow regulator is arranged in parallel with a non-return valve allowing a passage of fluid in the opposite direction to the unidirectional flow regulator. In other words, the non-return valve prevents the passage of fluid during opening - so as to force the passage of fluid through the unidirectional flow regulator selected during the opening phase - and allows the passage of fluid during the closing phase. The passage of the fluid through the non-return valve is not limited in terms of flow rate, the closure is considered to be instantaneous. As will be seen in a particular embodiment below, one of the flow regulators can be arranged in parallel with a flow rectifier, in order to allow if necessary to impose a determined flow of fluid during the closing phase. . In this case, instead of being instantaneous, closing takes place at first or second speed, depending on the location of the flow rectifier.

Finally, a third solenoid valve makes it possible to selectively block the circulation of fluid between the first chamber of the jack and the reservoir during the opening phase and, optionally, during the closing phase.

The table below shows the different modes of actuation of the actuator that can be obtained with at least two solenoid valves.

[Tables 1]

Figures 2, 3, 5 and 6 respectively illustrate the hydraulic diagrams corresponding to embodiments Nos 9, 25, 12 and 28, it being understood that the skilled person is able, from these examples , to define a hydraulic diagram for each of the other embodiments.

In these figures, the cylinder is assumed to be hydraulic, but the skilled person could transpose the teaching of these figures to a pneumatic cylinder without departing from the scope of the present invention.

FIG. 2 is a hydraulic diagram of embodiment n ° 9, based on a main bistable solenoid valve 20 and two monostable solenoid valves 21, 22.

The bistable solenoid valve 20 controls the opening or closing phase of the shutter. The monostable solenoid valve 22 controls a possible blocking of the shutter opening, while the monostable solenoid valve 21 controls a slow or fast speed of opening of the shutter.

In a manner known in itself, each monostable solenoid valve 21, 22 comprises an electromagnetic coil 211 (respectively 212), a drawer 221 (respectively 222) movable between a rest position for which the coil is not electrically supplied and an activated position for which the coil is electrically supplied, and a return means 231 (respectively 232) of the drawer towards its position

rest. Furthermore, the bistable solenoid valve 20 comprises two electromagnetic coils 201, 202, a slide 210 movable between a rest position where none of the coils 201, 202 is electrically supplied, a first activated position where the coil 201 is electrically supplied and a second activated position where the coil 202 is electrically powered, and two return means 220, 230 of the drawer.

In the solenoid valve 20, the rest position (which is that illustrated in Figure 2) blocks the passage of fluid from the reservoir to the first chamber 10 of the cylinder 1 and the passage of fluid from the second chamber 11 of the cylinder 1 towards the tank.

On the first channel, the two monostable solenoid valves 21, 22 are arranged in series with a parallel mounting of two unidirectional flow regulators 24, 25 each of which is mounted in parallel with a respective unidirectional check valve 240, 250 . It is assumed that the first flow regulator 24 imposes a slow speed of the jack while the second regulator 25 imposes a fast speed of the jack.

When the coil 202 of the solenoid valve 20 is electrically supplied, the drawer is moved upwards (relative to the configuration illustrated in Figure 2), thus allowing the passage of fluid from the reservoir to the second chamber 11 of the cylinder and the passage of fluid from the first chamber 10 of the cylinder to the reservoir (opening phase of the shutter).

In the solenoid valve 22, the rest position (which is that illustrated in Figure 2) allows the passage of fluid from the first chamber 10 of the cylinder to the solenoid valve 21. The position of the drawer 222 when the coil 212 is electrically powered (corresponding to a downward movement in the configuration illustrated in Figure 2) blocks the passage of fluid from the first chamber of the cylinder to the solenoid valve 21 and thus allows a blocking of the opening stroke of the shutter.

In the solenoid valve 21, the rest position (which is that illustrated in Figure 2) allows the passage of fluid through the second unidirectional flow regulator 25, imposing a rapid opening speed. When the coil 211 of the solenoid valve 21 is electrically supplied, the position of the slide 221 (corresponding to a downward displacement relative to the configuration illustrated in FIG. 2) sends the fluid to the first unidirectional flow regulator 24, imposing thus a slow opening speed of the shutter.

When the coil 201 of the main solenoid valve 20 is electrically supplied, the position of the slide 210 (corresponding to a downward displacement relative to the configuration illustrated in Figure 2) allows the passage of fluid from the tank towards the first chamber 10 of the jack and the passage of fluid from the second chamber 11 of the jack towards the reservoir (closing phase of the shutter).

In the solenoid valve 22, the rest position (which is that illustrated in Figure 2) allows the passage of fluid from the solenoid valve 21 to the first chamber 10 of the cylinder. Similarly, the position of the drawer 222 when the coil 212 is electrically powered (corresponding to a downward movement in the configuration illustrated in Figure 2) allows the passage of fluid from the solenoid valve 21 to the first chamber of the cylinder. In this configuration, it is therefore unnecessary to supply the coil of the solenoid valve 21 during the closing phase.

In the closing phase, the passage of fluid through flow regulators is not possible; the passage of fluid therefore takes place through one of the non-return valves, and the closing speed is considered to be instantaneous, the flow rate not being limited through said non-return valve.

In the solenoid valve 21, the rest position (which is that illustrated in Figure 2) allows the passage of fluid through the non-return valve 250 arranged in parallel with the second unidirectional flow regulator 25. When the coil 211 of the solenoid valve 21 is electrically supplied, the position of the slide 221 (corresponding to a downward displacement relative to the configuration illustrated in FIG. 2) allows the passage of fluid through the check valve 240 arranged in parallel of the first flow regulator 24. In this configuration, it is therefore unnecessary to supply the coil of the solenoid valve 21 during the closing phase.

Figure 3 is a hydraulic diagram of embodiment No. 25, implementing three monostable solenoid valves 20, 21, 22.

This embodiment is similar to that of embodiment No. 9, the only difference being that the main solenoid valve 20 which controls the opening or closing of the shutter is monostable and not bistable. The other elements of the hydraulic circuit will therefore not be described again.

At rest (corresponding to the configuration illustrated in Figure 3), the slide 210 of the solenoid valve 20 allows the passage of fluid from the reservoir to the first chamber 10 of the cylinder and from the second chamber 11 of the cylinder to the reservoir (shutter closing phase).

As in embodiment No. 9 illustrated in FIG. 2, the solenoid valves 21 and 22 can be left to stand and thus allow the passage of the fluid through the check valve 250 arranged in parallel with the second unidirectional regulator 25.

When the coil 201 of the solenoid valve 20 is electrically supplied, the slide 210 moves (upwards relative to the configuration illustrated in FIG. 3), thus allowing the passage of fluid from the reservoir to the second chamber 11 from the jack and from the first chamber 10 of the jack towards the reservoir (opening phase of the shutter).

In the solenoid valve 22, the rest position (which is that illustrated in Figure 3) allows the passage of fluid from the first chamber 10 of the cylinder to the solenoid valve 21. The position of the drawer when the coil 212 is electrically powered (corresponding to a downward movement in the configuration illustrated in Figure 3) blocks the passage of fluid from the first chamber 10 of the cylinder to the solenoid valve 21 and thus allows a blocking of the opening stroke of the shutter.

In the solenoid valve 21, the rest position (which is that illustrated in Figure 3) allows the passage of fluid through the second unidirectional flow regulator 25, imposing a rapid opening speed. When the coil 211 of the solenoid valve 21 is electrically supplied, the position of the slide 221 (corresponding to a downward displacement relative to the configuration illustrated in FIG. 3) sends the fluid to the first unidirectional flow regulator 24, imposing thus a slow opening speed of the shutter.

FIG. 4 illustrates an example of the shutter stroke curve over time that can be obtained with embodiments Nos. 9 and 25.

A zero stroke corresponds to a total closure of the shutter.

A first step 01 of the opening phase O is carried out at high speed, the solenoid valve 21 being at rest to provide a fluid connection between the first chamber 10 of the jack and the second unidirectional flow regulator 25.

A second step 02 of the opening phase O is carried out at low speed, the solenoid valve 21 being actuated to provide a fluid connection between the first chamber 10 of the jack and the first unidirectional flow regulator 24.

A third step 03 of the opening phase O is carried out with the shutter blocked, the solenoid valve 22 being actuated to block the circulation of fluid between the first chamber 10 of the jack and the solenoid valve 21.

A fourth step 04 of the opening phase O is carried out at low speed, the solenoid valve 22 being deactivated and the solenoid valve 21 being activated to provide a fluid connection between the first chamber 10 of the jack and the first unidirectional regulator debit 24.

A fifth step 05 of the opening phase O is carried out at high speed, the solenoid valve 21 being at rest to provide a fluid connection between the first chamber 10 of the jack and the second unidirectional flow regulator 25.

In a sixth step 06 of the opening phase O, the maximum opening stroke of the shutter being reached, it is blocked.

The closing step L1 is instantaneous, the fluid passing through one of the non-return valves arranged in parallel with a unidirectional flow regulator.

A second opening-closing sequence comprises a first step 01 ’at high speed, a second step 02’ with the shutter blocked, and an instantaneous closing step Fl ’.

It goes without saying that the curve of FIG. 4 is only a nonlimiting example among the plurality of sequences that the embodiments Nos. 9 and 25 make it possible to generate.

If you do not want to be able to block the opening stroke of the shutter but only influence the opening speed, you can remove the solenoid valve 22 from the hydraulic circuit shown in Figures 2 and 3.

Similarly, if one does not wish to vary the opening speed but have the possibility of blocking the opening stroke, one can remove the solenoid valve 21 and one of the flow regulators in the circuit hydraulics shown in Figures 2 and 3.

FIG. 5 is a hydraulic diagram of embodiment No. 12, based on a main bistable solenoid valve 20 and two monostable solenoid valves 21, 22.

Compared to embodiment n ° 9, the valve of the solenoid valve 22 has a state passing at rest and a blocking state in both directions when the coil 212 is electrically supplied. Furthermore, a flow rectifier 26 is arranged in parallel with the second unidirectional flow regulator 25. Said flow rectifier 26 comprises a plurality of unidirectional non-return valves arranged analogously to a diode bridge used to rectify an electric current. More precisely, the valves are arranged so that, when the solenoid valve 21 is at rest, whatever the direction of circulation of the fluid between the first chamber 10 of the jack and the reservoir, the fluid always passes through the second unidirectional regulator 25. In other words, this flow rectifier 26 makes it possible to impose a rapid closing speed - instead of instantaneous closing - in addition to the rapid opening speed provided by the unidirectional flow regulator 25 alone.

In the main solenoid valve 20, the rest position (which is that illustrated in FIG. 5) blocks the passage of fluid from the reservoir to the first chamber 10 of the jack 1 and the passage of fluid from the second chamber 11 from cylinder 1 to the tank.

When the coil 202 of the solenoid valve 20 is electrically supplied, the slide is moved upwards (relative to the configuration illustrated in FIG. 5), thus allowing the passage of fluid from the reservoir to the second chamber 11 of the cylinder and the passage of fluid from the first chamber 10 of the cylinder to the reservoir (opening phase of the shutter).

In the solenoid valve 22, the rest position (which is that illustrated in Figure 5) allows the passage of fluid from the first chamber 10 of the cylinder to the solenoid valve 21. The position of the drawer 222 when the coil 212 is electrically powered (corresponding to a downward movement in the configuration illustrated in FIG. 5) blocks the passage of fluid from the first chamber of the jack to the solenoid valve 21 and thus allows a blocking of the opening stroke of the shutter.

In the solenoid valve 21, the rest position (which is that illustrated in Figure 5) allows the passage of fluid through the second unidirectional flow regulator 25, imposing a rapid opening speed. When the coil 211 of the solenoid valve 22 is electrically supplied, the position of the slide 221 (corresponding to a downward displacement relative to the configuration illustrated in FIG. 5) sends the fluid to the first unidirectional flow regulator 24, imposing thus a slow opening speed of the shutter.

When the coil 201 is electrically powered, the position of the drawer (corresponding to a downward displacement relative to the configuration illustrated in Figure 5) allows the passage of fluid from the reservoir to the first chamber 10 of the cylinder and the passage of fluid from the second chamber 11 from the jack to the reservoir (closing phase of the shutter).

In the solenoid valve 22, the rest position (which is that illustrated in Figure 5) allows the passage of fluid from the solenoid valve 21 to the first chamber 10 of the cylinder. The position of the spool 222 when the coil 212 is electrically supplied (corresponding to a downward displacement in the configuration illustrated in FIG. 5) blocks the passage of fluid from the solenoid valve 21 to the first chamber 10 of the jack and thus allows a blocking of the shutter closing stroke.

In the solenoid valve 21, the rest position (which is that illustrated in Figure 5) allows the passage of fluid through the flow rectifier 26 and the second unidirectional flow regulator 25, imposing a fast closing speed . When the coil 211 of the solenoid valve 21 is electrically supplied, the position of the slide 221 (corresponding to a downward displacement relative to the configuration illustrated in FIG. 5) allows the passage of fluid through the non-return valve 240 arranged in parallel with the first flow regulator 24. The closure of the shutter is then instantaneous.

FIG. 6 is a hydraulic diagram of embodiment No. 28, implementing three monostable solenoid valves 20, 21, 22.

This embodiment is to be compared to that of embodiment No. 12 illustrated in FIG. 5, the only difference between these two embodiments being that the main solenoid valve 20 which controls the opening or closing of the shutter is monostable and not bistable. The other elements of the hydraulic circuit and their operation will therefore not be described again during an opening-closing sequence of the shutter.

FIGS. 7A and 7B are examples of curves of the travel C of the shutter during an open-close cycle which can be obtained with embodiments Nos. 12 and 28.

The signals SI, S2, S3 of each of the three channels of the sequential control unit connected respectively to the solenoid valves 20, 21, 22 have either a zero amplitude (OFF) or an amplitude of a determined value (ON) . The OFF state corresponds to an absence of supply to the coil considered.

In a first step 01 of the opening phase O, the signal SI is in the ON state while the signals S2 and S3 are in the OFF state. The cylinder begins its opening stroke at high speed.

In a second step 02 of the opening phase O, the signal SI is always in the ON state and the signal S2 changes to the ON state (actuation of the solenoid valve 21), the signal S3 remaining at OFF state. The cylinder stroke slows down at slow speed.

In a third step 03 of the opening phase O, the signal SI is always in the ON state and the signal S3 goes to the ON state (activation of the solenoid valve 22), the signal 52 passing to OFF state (deactivation of solenoid valve 21) or not. The cylinder stroke is then blocked.

In a fourth step 04 of the opening phase O, the signal SI is always in the ON state and the signal S2 goes to the ON state (activation of the solenoid valve 21), the signal 53 passing to OFF state (deactivation of the solenoid valve 22). The cylinder stroke then resumes with slow speed.

In a fifth step 05 of the opening phase O, the signal SI is always in the ON state and the signal S2 changes to the OFF state (deactivation of the solenoid valve 21), the signal S3 remaining at OFF state. The cylinder stroke then continues at high speed.

In a sixth step 06 of the opening phase O, the signal SI is always in the ON state. The maximum opening travel Cmax of the shutter being reached, it is blocked.

To initiate the closing phase F, the signal SI goes to the OFF state. The signals S2 and S3 remaining in the OFF state, the fluid passes through the second unidirectional flow regulator 25 via the flow rectifier 26, thus imposing a fast closing speed during step F1.

In a second closing step F2, the signal S3 goes to the ON state (activation of the solenoid valve 22) and causes the shutter to be blocked.

In a third closing step F3, the signal S3 goes to the OFF state (deactivation of the solenoid valve 22) and the signal S2 goes to the ON state (activation of the solenoid valve 21), thus causing a instantaneous closing (the fluid passing through the non-return valve 240).

FIG. 7B presents a curve similar to that of FIG. 7A, differing only in the third closing step F3 which is carried out at high speed and not instantaneously. This step is implemented by maintaining the solenoid valve 21 at rest (signal S2 remaining OFF), so as to pass the fluid through the second unidirectional flow regulator 25 via the flow rectifier 26.

It goes without saying that the curves of FIGS. 7A and 7B are only nonlimiting examples among the plurality of sequences that the embodiments Nos. 12 and 28 make it possible to generate.

If one does not wish to be able to block the opening and closing travel of the shutter but only to influence the opening and closing speed, the solenoid valve 22 can be removed from the hydraulic circuit shown in the Figures 5 and 6.

Similarly, if one does not wish to vary the speed of opening or closing but have the possibility of blocking the opening or closing stroke, one can remove the solenoid valve 21 and one of the flow regulators of the hydraulic circuit shown in Figures 5 and 6.

We are now interested in the case of an electric actuator.

Unlike the hydraulic cylinder and the pneumatic cylinder, the electric cylinder is not powered by a fluid but by an electric current which powers a motor coupled to the rod of the cylinder.

To this end, the actuator control device comprises an electronic card comprising at least two electronic components among: [0148] - a component for adjusting the speed of the actuator to a first speed, [0149] - a component for adjusting the speed of the jack at a second speed greater than the first, [0150] - a component for blocking the stroke of the jack.

The components of the electronic card are previously programmed according to techniques known per se.

The sequential control unit is identical to that described for the embodiments relating to the hydraulic cylinder and the pneumatic cylinder; it will therefore not be described again in detail.

The control unit comprises at least two control channels, each electrically connected to one of the components of the electronic card.

Thus, the sending of a control signal by a first control channel to one of the components (for example, a component for adjusting the speed of the jack) triggers the operation of the engine of the jack so as to obtain the desired sliding speed.

A control signal sent by a second control channel to the other component (for example, the component for blocking the stroke of the jack) has the effect of stopping the motor to immobilize the jack.

One can thus obtain curves of the cylinder stroke during an opening-closing sequence of the shutter similar to those of Figures 4, 7A and 7B.

Finally, it goes without saying that the examples which have just been given are only particular illustrations in no way limiting as to the fields of application of the invention.

List of documents cited [0158] EP 2 679 374 [0159] EP 2 604 408

Claims (1)

Claims [Claim 1] Control system for a shutter arranged to slide in a plastic injection nozzle, comprising: - an electric motor coupled to said shutter to drive it in sliding mode between a shutter position of the nozzle and a position for maximum opening of the nozzle, - a motor control device (2), comprising at least two components integrated in an electronic motor control card, said components being chosen from: * a component suitable for regulating the stroke of the shutter at a first constant speed, * a component adapted to regulate the stroke of the shutter at a second constant speed, greater than the first speed, * a component adapted to selectively block the stroke of the shutter, - a sequential control unit comprising at least two control channels (30, 31, 32), configured to selectively send an electrical signal control device (2) by one and / or the other of said control channels (30, 31, 32) so that: - under the effect of a first signal sent by the first control channel (30), one of the components is activated, - under the effect of a second signal sent by the second control channel (31), another component is activated. [Claim 2] System according to claim 1, wherein the electric motor or the shutter is provided with a position sensor and the sequential control unit is configured to control the emission of the control signals according to the measurements provided by said position sensor. [Claim 3] System according to claim 2, in which the sequential control unit is configured to take into account at least one of the following data: a time of the injection process, a position of a sensor, pressure or temperature in the injection tool, a signal from the injection press. [Claim 4] System according to one of claims 1 to 3, wherein the sequential control unit (3) is configured to send an electrical control signal in the form of direct current. [Claim 5] System according to one of claims 1 to 3, wherein the sequential control unit (3) is configured to send an electrical control signal in the form of alternating current.