WO2015104991A1

WO2015104991A1 - Moulding machine

Info

Publication number: WO2015104991A1
Application number: PCT/JP2014/083959
Authority: WO
Inventors: 慶彦青山
Original assignee: 東洋機械金属株式会社
Priority date: 2014-01-08
Filing date: 2014-12-22
Publication date: 2015-07-16
Also published as: CN105745057A; JP2015128874A

Abstract

Provided is a moulding machine with which a simple configuration can be used to adjust mould-clamping force with ease, without having to provide expensive sensors such as mould-clamping load cells. A control device (8) is provided with a mould-clamping-force determination mode. When the mould-clamping-force determination mode is selected, the control device (8) drives a mould-clamping unit (3) to clamp a mould device (5) with a predetermined mould-clamping force, and subsequently drives an ejection mechanism (6) to press, at a constant torque, against a mating surface (15a) of a fixed-side mould (15), an article push-out member (such as a return pin (45) or an ejection plate (50)) provided to the ejection mechanism (6). An injection unit (4) is subsequently driven to inject a moulding material into a mould cavity (17) and fill said cavity therewith. The operation state of the ejection mechanism (6) during injection is displayed on a display device (7), and the suitability of the mould-clamping force is determined.

Description

Molding machine

The present invention relates to a molding machine such as an injection molding machine and a die casting machine, and particularly relates to a technique for easily detecting the opening of a mold during injection and facilitating adjustment of a clamping force.

The molding machine has a mold clamping unit and an injection unit. The mold clamping unit is used to clamp the fixed mold and the moving mold with an appropriate clamping force, and then these molds are clamped. A molded product having a predetermined shape is manufactured by injecting and filling a molten molding material from an injection unit into a cavity formed between a fixed mold and a movable mold. If the mold clamping force is insufficient, defective molding such as burrs occurs, and if the mold clamping force is excessive, the life of the fixed side mold and the movable side mold is adversely affected. Therefore, it is desirable to adjust the mold clamping force to a minimum value that does not cause molding defects such as burrs in the product.

The applicant of the present application first has a mold clamping load cell for detecting the mold clamping force in the mold clamping unit, and the moving die is fixed with the moving die plate advanced to the position farthest from the tailstock. Performing a first tailstock position adjusting step for moving the tailstock to a position in contact with the side mold and a second tailstock position adjusting step for moving the tailstock to a position where a predetermined mold clamping force can be generated; Furthermore, a method of determining a mold clamping force has been proposed in which a zero point correcting step of automatically correcting the zero point of the mold clamping load cell is performed before the second tailstock position adjusting step is executed. (For example, refer to Patent Document 1). According to this mold clamping force determination method, the zero point correction of the mold clamping load cell is automatically performed, so that the accuracy of adjusting the mold clamping force can be improved, and the frequency of occurrence of molding failure and the frequency of destruction of the apparatus can be reduced.

JP 2009-006555 A

However, the mold clamping force determination method previously proposed by the applicant of the present application requires the mold clamping unit to be equipped with a mold clamping load cell, which makes the molding machine expensive. Further, instead of the mold clamping load cell, a tie bar sensor that detects the tension acting on the tie bar, or a mold opening amount sensor that directly detects the mold opening amount of the fixed side mold and the moving side mold may be considered. However, since the molding machine becomes expensive, it is difficult to adopt.

The present invention has been made to solve such problems of the prior art, and its purpose is to detect the opening of the mold during injection with a simple configuration and to easily adjust the clamping force. It is to provide a viable molding machine.

In order to solve the above-described problems, the present invention provides a mold clamping unit, an injection unit that injects and fills a molding material into a cavity of a mold apparatus clamped by the mold clamping unit, and a molded product as the mold. An ejection mechanism that pushes out from the apparatus; a display device that displays an operation state of the mold clamping unit, the injection unit, and the ejection mechanism; and a drive of the mold clamping unit, the injection unit, the ejection mechanism, and the display device. And a control device having a mold clamping force determination mode as one of control modes, and when the molding machine operator selects the mold clamping force determination mode, the mold clamping is performed. After the unit is driven and the mold apparatus is clamped with a preset clamping force, the drive of the eject mechanism is torque-controlled to prepare for the eject mechanism. The product extruding member thus pressed is pressed against the mating surface of the fixed mold constituting the mold apparatus with a constant torque, and then the injection unit is driven to inject and fill the molding material into the cavity. The operation state of the ejection mechanism at the time of injection / filling of the molding material is displayed on the display device.

After the mold clamping is completed, if the product extruding member provided in the eject mechanism is pressed against the mating surface of the fixed mold with a constant torque, injection and filling of the molding material into the cavity will provide sufficient mold clamping force. When the height is high, the stationary mold and the movable mold constituting the mold apparatus are maintained in the mold closed state, so that the position of the product pushing member does not change. On the other hand, when the mold clamping force is insufficient, the mating surface of the stationary mold and the movable mold opens during the period when the injection pressure exceeding the mold clamping force is acting in the cavity. The position of the product push-out member changes according to the state change of the mold apparatus. Therefore, the operator of the molding machine can easily and accurately determine the appropriateness of the mold clamping force by monitoring the change in the position of the product pushing member displayed on the display device. Therefore, expensive sensors such as a mold clamping load cell can be used. The mold clamping force can be adjusted without providing.

In order to solve the above-mentioned problems, the present invention provides a mold clamping unit, an injection unit for injecting and filling a molding material into a cavity of a mold apparatus clamped by the mold clamping unit, and a molded product as the mold. An ejection mechanism that pushes out from the mold device; a display device that displays an operation state of the mold clamping unit, the injection unit, and the ejection mechanism; and a drive of the mold clamping unit, the injection unit, the ejection mechanism, and the display device. The control device has a mold clamping force determination mode as one of the control modes, and when the operator of the molding machine selects the mold clamping force determination mode, the mold After the clamping unit is driven and the mold apparatus is clamped with a preset clamping force, the drive of the eject mechanism is position-controlled so that the eject mechanism The obtained product extruding member is pressed against the mating surface of the fixed mold constituting the mold apparatus, and then the injection unit is driven to inject and fill the molding material into the cavity. The operation state of the ejection mechanism at the time of injection / filling is displayed on the display device.

According to such a configuration, when the mold clamping force is sufficiently high at the time of injection / filling of the molding material into the cavity, the fixed side mold and the movable side mold constituting the mold apparatus are maintained in the mold closed state. Therefore, the torque applied to the eject mechanism does not change. On the other hand, when the mold clamping force is insufficient, the mating surface of the stationary mold and the movable mold opens during the period when the injection pressure exceeding the mold clamping force is acting in the cavity. The torque applied to the eject mechanism changes according to the state change of the mold apparatus. Accordingly, the operator of the molding machine can easily and accurately determine the appropriateness of the mold clamping force by monitoring the torque change of the eject mechanism displayed on the display device, and thus includes expensive sensors such as a mold clamping load cell. Therefore, the mold clamping force can be adjusted.

Further, the present invention is characterized in that, in the molding machine configured as described above, the product pushing member is an eject pin provided in a return pin type eject mechanism.

According to such a configuration, it is possible to easily detect the opening of the mold and facilitate the adjustment of the clamping force of the molding machine having the return pin type eject mechanism.

Further, the present invention is characterized in that, in the molding machine having the above-described configuration, the product pushing member is a stripper plate provided in a plate type eject mechanism.

With such a configuration, it is possible to easily detect the opening of the mold and facilitate the adjustment of the clamping force for a molding machine equipped with a plate-type eject mechanism.

According to the present invention, the mold clamping force can be determined without providing expensive sensors such as a mold clamping load cell, so that the configuration of the molding machine can be simplified and the cost can be reduced.

It is a block diagram of the molding machine which concerns on embodiment. It is a block diagram of the mold clamping unit which concerns on embodiment. It is a flowchart which shows the procedure of the clamping force determination performed with the molding machine which concerns on embodiment. It is a graph which shows the change of an eject pin position when the mold clamping force is inadequate when a fixed torque is provided to the eject pin in the mold clamping state. It is a graph which shows the torque change of the electric servomotor for ejection when the mold clamping force is inadequate when the position control of the advance position of the eject pin is performed in the mold clamping state. It is a block diagram of the molding machine provided with the plate-type eject mechanism.

Hereinafter, the molding machine according to the embodiment will be described by taking an injection molding machine as an example. Needless to say, the present invention is not limited to the embodiments described below, and can easily be applied to molding machines having other configurations without departing from the spirit of the present invention.

As shown in FIG. 1, the molding machine 1 of this example is an injection molding machine, and includes a machine base 2, a mold clamping unit 3, an injection unit 4, a mold device 5, an eject mechanism 6, and these There is a display device 7 for displaying the operating state of the mold clamping unit 3, the injection unit 4 and the eject mechanism 6, and a control device 8 for controlling the driving of the mold clamping unit 3, the injection unit 4, the eject mechanism 6 and the display device 7. is doing.

As shown in an enlarged view in FIG. 2, the mold clamping unit 3 includes a fixed die plate 11, a tail stock 12 disposed opposite to the fixed die plate 11, and both ends of the fixed die plate 11 and the tail stock 12. Has a plurality of tie bars 13 that are bridged, and a movable die plate 14 that is guided by the tie bars 13 and moves between the fixed die plate 11 and the tailstock 12. The fixed die plate 11 is fixed to the upper surface of the machine base 2. On the other hand, the tailstock 12 is movably attached to the upper surface of the machine base 2 within a range in which the mold thickness can be adjusted. One end of the tie bar 13 is fixed to the fixed die plate 11, and the other end slidably penetrates into a tie bar through hole (not shown) provided in the tail stock 12. A fixed die 15 constituting the mold device 5 is attached to the surface of the fixed die plate 11 facing the moving die plate 14, and the mold device is mounted on the surface of the moving die plate 14 facing the fixed die plate 11. 5 is attached. Between the mating surface 15a of the stationary mold 15 and the mating surface 16a of the moving mold 16, a cavity 17 having a predetermined shape is formed during mold clamping.

The mold clamping unit 3 includes a mold opening / closing electric servomotor 18, a ball screw mechanism 19 that converts the rotational movement of the mold opening / closing electric servomotor 18 into a linear movement, and a mold opening / closing electric motor via the ball screw mechanism 19. A toggle link mechanism 20 driven by the servo motor 18 is further provided. Both ends of the link member constituting the toggle link mechanism 20 are connected to the tail stock 12 and the movable die plate 14, respectively. The ball screw mechanism 19 includes a nut body 19a that is rotatably held on the tail stock 12, and a screw shaft 19b that is passed through the tail stock 12 while being screwed to the nut body 19a. One end is connected to the cross head 20 a of the toggle link mechanism 20. Further, the mold opening / closing electric servomotor 18 is fixed to the tailstock 12, and a timing belt 21 wound between a pulley 18a attached to an output shaft thereof and a pulley 19c attached to a nut body 19a. The rotational motion is transmitted to the nut body 19a via the.

Accordingly, when the tail opening 12 is fixed to the machine base 2 and the mold opening / closing electric servomotor 18 is driven in accordance with a command from the control device 8 and the toggle link mechanism 20 is extended, the movable die plate 14 is moved to the tie bar 13. Are moved to the fixed die plate side, and the mold is closed and the subsequent mold clamping is performed. On the contrary, when the tailstock 12 is fixed to the machine base 2, the mold opening / closing electric servomotor 18 is driven in accordance with a command from the control device 8, and the toggle link mechanism 20 is contracted. 13 is guided to the tail stock 12 side and mold opening is performed.

As shown in FIG. 1, the injection unit 4 includes a cylindrical heating cylinder 32 having an injection nozzle 33 attached to the tip thereof, a screw 34 housed in the heating cylinder 32 so as to be rotatable and movable back and forth, and a raw material A hopper 35 for charging the resin and a hopper block 31 for supplying the raw resin charged in the hopper 35 into the heating cylinder 32 are provided. A band heater 36 for heating the resin supplied into the heating cylinder 32 is wound around the outer periphery of the heating cylinder 32. The injection unit 4 includes a metering electric servo motor and an injection electric servo motor (not shown), and transmits the power of each motor to the screw 34 via a required power transmission mechanism. Therefore, when the electric metering servomotor is driven in accordance with a command from the control device 8 and the screw 34 in the heating cylinder 32 is rotationally driven, the raw material resin introduced into the hopper 35 in accordance therewith is put into the heating cylinder 32. be introduced. The raw material resin introduced into the heating cylinder 32 is melted by the frictional heat and shearing heat generated by the rotational drive of the screw 34 and the heat generated by the band heater 36, and is sequentially transferred to the injection nozzle 33 side for a predetermined amount. Molten resin is stored at the tip of the heating cylinder 32. Next, the injection electric servo motor is driven in accordance with a command from the control device 8, the screw 34 is driven forward, and a predetermined amount of molten resin stored at the tip of the heating cylinder 32 is transferred from the injection nozzle 33 to the mold. It is injected and filled into the cavity. Thereby, a molded product having a predetermined shape is obtained.

The eject mechanism 6 includes a ball screw mechanism 42 as shown in FIG. The ball screw mechanism 42 includes a nut body 42a rotatably held on the movable die plate 14, and a screw shaft 42b screwed to the nut body 42a. Is also provided with an eject pin 42c having a small diameter. Further, in the moving side mold 16, when the eject plate 43 and the eject pin 42c are retracted but the eject plate 43 is not retracted, the eject plate is forcibly closed by closing the mold. An eject plate 43 that holds a return pin 45 that retracts 43 is provided. The ejecting electric servo motor 41 is fixed to the moving die plate, and is wound around a pulley 41a attached to the output shaft thereof and a pulley 42d attached to the nut body 42a of the ball screw mechanism 42. The rotational motion is transmitted to the nut body 42a via the belt 46. When the nut body 42a is rotationally driven, the screw shaft 42b, the eject pin 42c, and the eject plate 43 screwed together with the nut body 42a advance integrally, and the product protruding pin 44 fixed to the eject plate 43 also advances. Start. As a result, a predetermined amount of the product protruding pin 44 protrudes from the tip of the movable mold 16, and the molded product A is taken out from the movable mold 16.

As shown in FIG. 1, the display device 7 is arranged on the front surface of the machine base 2 at a position where it can be easily seen by the operator. The display device 7 can be integrally provided with an input device 7a. The control device 8 is installed inside the machine base 2. The display device 7 includes a list of detection data of various sensors (not shown) provided in the mold clamping unit 3, the injection unit 4, and the ejection mechanism 6, and calculation data of the control device 8 based on these detection values. It is displayed in a desired format such as display or graph display. In the molding machine of this example, the output torque value of the ejecting electric servo motor 41 when the operator selects the mold clamping force determination mode and the tip position of the eject pin 42c are also displayed on the display device 7. The output torque value of the ejecting electric servomotor 41 is calculated based on the current value supplied to the ejecting electric servomotor 41, and the tip position of the eject pin 42c is shown in the figure. It can be calculated from the output signal of the rotary encoder that does not.

The control device 8 controls the entire molding machine 1 including the mold clamping unit 3, the injection unit 4, the eject mechanism 6, and the display device 7. The control device 8 includes an input device 7 a, and the operator of the molding machine inputs the input device. By operating 7a, it is configured to be switched to various control modes such as a molding condition setting mode, a mold clamping force determination mode, a mold thickness adjustment mode, a continuous operation mode, and a display switching mode. When the operator of the molding machine selects the mold clamping force determination mode, the control device 8 controls the drive of the mold clamping unit 3, the injection unit 4 and the ejection mechanism 6 according to a predetermined procedure shown in FIG. The calculation of the output torque value of the servo motor 41 and the calculation of the tip position of the eject pin 42c are performed, and each calculation result is displayed on the display device 7 in the graph display mode. 4 and 5 show display examples of the output torque value of the ejecting electric servo motor 41 and the tip position of the eject pin 42c. The display mode can be switched by operating the input device 7a of the control device 8.

Hereinafter, the driving procedure of the mold clamping unit 3, the injection unit 4 and the eject mechanism 6 in the mold clamping force judgment mode and the method for judging whether or not the mold clamping force is appropriate will be described with reference to FIGS. FIG. 3 is a flowchart showing the procedure of the mold clamping force determination mode. FIG. 4 shows the change in the eject pin position when the mold clamping force is insufficient when a constant torque is applied to the eject pin 42c in the mold clamping state. FIG. 5 is a graph showing the torque change of the ejecting electric servo motor 41 when the mold clamping force is insufficient when the forward position of the eject pin 42c is controlled in the mold clamping state. . As described above, the method for determining the appropriateness of the mold clamping force includes a method of applying a constant torque to the eject pin 42c in the mold clamping state and monitoring a change in the position of the eject pin before and after the injection process, and a mold clamping state. There is a method of controlling the position of the forward position of the eject pin 42c and monitoring the torque change of the eject electric servo motor 41 before and after the injection process.

First, a method of monitoring a change in the position of the eject pin before and after the injection process by applying a constant torque to the eject pin 42c in the mold clamping state will be described. The determination of the mold clamping force is executed by the operator of the molding machine operating the input device 7a and selecting the mold clamping force determination mode after completing the replacement of the mold apparatus 5 and adjusting the mold thickness. As shown in FIG. 3, when the operator of the molding machine starts the mold clamping force determination mode (procedure S1), the control device 8 drives the mold opening / closing electric servo motor 18 to perform mold clamping, and the mold clamping is completed. A state is set (step S2).

Next, the control device 8 drives the eject mechanism 6 and presses the tip of the return pin 45 against the mating surface 15a of the fixed mold 15 with a constant torque (step S3). When the electric servomotor 41 for ejection is rotationally driven with a constant torque in a predetermined direction with the tip end portion of the return pin 45 retracted into the movable mold 15, the rotational motion is linearized by the ball screw mechanism 42. It is converted into motion to drive the eject plate 43, and the tip of the return pin 45 is pressed against the mating surface 15 a of the fixed mold 15. The control device 8 keeps the output torque value of the ejecting electric servomotor 41 constant even after the tip of the return pin 45 is pressed against the mating surface 15a of the stationary mold 15. The output torque value of the ejecting electric servo motor 41 at this time does not affect the mold clamping force of the mold apparatus 5 and is a predetermined value that can move the return pin 45 following the behavior of the mold apparatus 5. And

Next, the control device 8 drives the injection unit 4 and advances the screw 34 in the heating cylinder 32 to inject and fill the molten resin in the heating cylinder 32 into the cavity 17 of the mold device 5. (Procedure S4). At this time, the injection pressure of the molten resin acts on the mold apparatus 5. When the mold clamping force is larger than the injection pressure, the mating surfaces 15a and 16a of the

molds

15 and 16 remain closed, but when the mold clamping force is smaller than the injection pressure, the

molds

15 and 16 The mating surfaces 15a and 16a are opened. As described above, in the mold-clamped state, the tip of the return pin 45 is pressed against the mating surface 15a of the fixed mold 15 with a constant torque, so that the mating surfaces 15a and 16a of the

molds

15 and 16 are opened. Then, as shown in FIG. 4, the return pin 45 (eject pin 42 c) moves forward during a period when the injection pressure exceeds the mold clamping force. The operator of the molding machine determines whether or not the mating surfaces 15a and 16a of the

molds

15 and 16 are opened by monitoring the display screen of the display device 7 (step S5).

In step S5, when it is determined that the mating surfaces 15a and 16a of the

molds

15 and 16 are opened (when determined as Yes in FIG. 3), the mold clamping force is adjusted, and the mold clamping force determination mode is set again. Execute. On the other hand, if it is determined in step S5 that the mating surfaces 15a and 16a of the

molds

15 and 16 remain closed (when determined No in FIG. 3), it can be determined that the mold clamping force is appropriate at present. Then, the mold clamping force determination mode is terminated.

Next, a method of controlling the position of the advance position of the eject pin 42c in the mold clamping state and monitoring the torque change of the ejecting electric servo motor 41 before and after the injection process will be described. In this method, in step S3 of FIG. 3, the control device 8 drives the eject pin 42c forward, and advances the tip of the return pin 45 to a position where it abuts against the mating surface 15a of the fixed mold 15. When the electric servomotor 41 for ejection is driven to rotate in a predetermined direction while the tip of the return pin 45 is retracted into the moving mold 15, the rotational motion is converted into linear motion by the ball screw mechanism 42. Then, the eject plate 43 is driven, and the position of the return pin 45 is controlled at a position where the tip of the return pin 45 comes into contact with the mating surface 15 a of the fixed mold 15. The position of the eject pin 42c at this time is a position where a driving torque is applied at a position where the eject pin 42c is pressed against the mating surface 15a of the fixed mold 15.

molds

15 and 16 The mating surfaces 15a and 16a are opened. As described above, in the mold clamping state, the position of the tip of the return pin 45 is controlled at a position where it is pressed against the mating surface 15a of the stationary mold 15, so that the mating surfaces 15a and 16a of the

molds

15 and 16 are controlled. When is opened, as shown in FIG. 5, during the period in which the injection pressure exceeds the mold clamping force, the torque for position control at the position where the return pin 45 (eject pin 42c) is pressed is temporarily reduced. The operator of the molding machine determines whether or not the mating surfaces 15a and 16a of the

molds

In step S5, when it is determined that the mating surfaces 15a and 16a of the

molds

Thus, according to the molding machine according to the embodiment, the operator of the molding machine monitors the change in the position of the eject pin 42c displayed on the display device 7 or the change in the output torque of the electric servo motor 41 for ejection. Therefore, it is possible to easily detect the opening of the mold and determine whether or not the mold clamping force is appropriate. Therefore, it is possible to adjust the mold clamping force without providing expensive sensors such as a mold clamping load cell. . Therefore, it is possible to facilitate determination and adjustment of the mold clamping force for a molding machine equipped with a return pin type eject mechanism.

In the above embodiment, the molding machine provided with the return pin type eject mechanism 6 has been described as an example, but the present invention can also be applied to a molding machine equipped with a plate type eject mechanism. As shown in FIG. 6, the plate-type eject mechanism is a type in which the molded product A is taken out by an eject plate 50 disposed between the fixed mold 15 and the movable mold 16 instead of the eject pin. This is the eject mechanism.

In the above-described embodiment, the case where the mold clamping force determination mode is performed alone has been described. However, the present invention can also be used for determination of mold opening during the continuous molding mode.

DESCRIPTION OF SYMBOLS 1 Molding machine 2 Machine stand 3 Clamping unit 4 Injection unit 5 Mold apparatus 6 Eject mechanism 7 Display apparatus 7a Input apparatus 8 Control apparatus 15 Fixed side mold 15a Mating surface 16 Moving side mold 16a Mating surface 18 Electric motor for mold opening / closing Servo motor 19 Ball screw mechanism 20 Toggle link mechanism 20a Cross head 41 Electric servo motor for ejecting 42 Ball screw mechanism 43 Ejecting plate 44 Ejecting pin 45 Return pin 46 Timing belt 50 Ejecting plate

Claims

A mold clamping unit, an injection unit for injecting and filling a molding material into a cavity of a mold apparatus clamped by the mold clamping unit, an eject mechanism for pushing out a molded product from the mold apparatus, the mold clamping unit, In a molding machine comprising: a display device that displays an operation state of the injection unit and the ejection mechanism; and a control device that controls driving of the mold clamping unit, the injection unit, the ejection mechanism, and the display device.
The control device has a mold clamping force determination mode as one of the control modes. When the molding machine operator selects the mold clamping force determination mode, the mold device is driven in advance by driving the mold clamping unit. After clamping with a set clamping force, the drive of the ejection mechanism is torque controlled, and the product pushing member provided in the ejection mechanism is used as the mating surface of the stationary mold that constitutes the mold apparatus After that, the injection unit is driven to inject and fill the molding material into the cavity, and the operation state of the ejection mechanism at the time of injection and filling of the molding material is displayed on the display device. A molding machine characterized by that.
A mold clamping unit, an injection unit for injecting and filling a molding material into a cavity of a mold apparatus clamped by the mold clamping unit, an eject mechanism for pushing out a molded product from the mold apparatus, the mold clamping unit, In a molding machine comprising: a display device that displays an operation state of the injection unit and the ejection mechanism; and a control device that controls driving of the mold clamping unit, the injection unit, the ejection mechanism, and the display device.
The control device has a mold clamping force determination mode as one of the control modes. When the molding machine operator selects the mold clamping force determination mode, the mold device is driven in advance by driving the mold clamping unit. After clamping with a set clamping force, the drive of the ejection mechanism is position-controlled, and the product pushing member provided in the ejection mechanism is used as the mating surface of the stationary mold constituting the mold apparatus After that, the injection unit is driven to inject and fill the molding material into the cavity, and the operation state of the eject mechanism at the time of injection and filling of the molding material is displayed on the display device. And molding machine.
3. The molding machine according to claim 1, wherein the product push-out member is an eject pin provided in a return pin type eject mechanism.
The molding machine according to any one of claims 1 and 2, wherein the product pushing member is a stripper plate provided in a plate-type eject mechanism.