JPS61283519A - Mold-clamping device of injection molder - Google Patents

Abstract

PURPOSE:To easily manufacture a mold-clamping device, which can be miniaturized, by lessening the loads applied to the respective main cylinders by a method wherein an intermediate platen is made shiftable by means of a plurality of the main cylinders and the pressing force by a plurality of the main cylinders is made to act on a movable platen through the intermediate platen and distance bars. CONSTITUTION:An intermediate platen 28 is shiftably arranged at the back of a movable platen 22 and made to be shiftable by means of a plurality of main cylinders 30. At the same time, side cylinders 33 are provided between the intermediate platen 28 and the movable platen 22. When the movable platen 22 and the intermediate platen 28 are brought close to each other by means of the side cylinders, distance bars 72 are made so as to be inserted in through holes provided on the intermediate platen 28. The pressing force by a plurality of the main cylinders 30 is so constituted as to act through the intermediate platen 28 and the distance bars 72 to the movable platen 22 in the state that the insertion of the distance bars 72 into said through holes is interrupted by a locking member. According to the structure as mentioned above, the total length of the main cylinder can be reduced and consequently the miniaturization of the mold-clamping device is possible and the manufacture of the whole mold-clamping device becomes easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a mold clamping device for an injection molding machine, and particularly relates to a mold clamping device for an injection molding machine, and particularly for a type of mold in which side cylinders are used to open and close the mold, and clamping operations are performed using the main cylinder. This invention relates to improvements to tightening devices.

(Prior art) In the mold clamping device of an injection molding machine, the movable platen is moved relative to the fixed platen, and thereby the opening/closing operation and clamping operation of the mold are performed between the movable platen and the fixed platen. In such a mold clamping device, a side cylinder that can be driven at high speed is used to open and close the mold, and a main cylinder that can provide sufficient pressing force is used to clamp the mold. There is a format. One type of type II device is a so-called hydromechanical mold clamping device. This is equipped with a gap-maintaining piston on the back of the movable platen, and when the mold is opened, the gap-maintaining piston is accommodated in a housing hole formed in the main ram of the main cylinder, while during press-clamping, the gap-maintaining piston is housed in a housing hole formed in the main ram of the main cylinder. A predetermined block is inserted between the gap retaining piston protruding from the main ram and preventing the piston from retreating,
The main ram's pressing force is applied to the movable platen through its block and gap-maintaining piston, and compared to the so-called direct pressure type in which the movable platen is directly pressed by the main ram, the main cylinder It has the advantages of being able to shorten the overall length of the engine and requiring less hydraulic oil.

(Problem) However, in such hydromechanical mold clamping devices, the mold clamping operation was conventionally performed with one main cylinder, so in order to obtain a large pressing force, the diameter of the main ram was increased. It was inevitably thick, which posed the problem of making it difficult to manufacture the material for the main ram and machining it, as well as making it difficult to manufacture the main cylinder.

In addition, in conventional hydromechanical mold clamping devices, as mentioned above, in order to allow the gap-holding piston to retreat when the mold is opened, it is necessary to form an accommodation hole in the main ram to accommodate the gap-holding piston. For some reason, there was a problem in that the length of the main ram was limited by the depth of its accommodation hole, that is, the distance the movable platen could move.

(Solution Means) Here, the present invention has been made in view of the above-mentioned circumstances, and its gist is that by moving the movable plates relative to the fixed plate, the movable plates can be moved. In a mold clamping device for an injection molding machine, the mold opening/closing operation and the clamping operation of the mold are performed between the movable platen and the fixed platen, in which an intermediate plate is movably disposed behind the movable platen, and the intermediate platen is movably disposed behind the movable platen. can be moved by a plurality of main cylinders, and a side cylinder is provided between the intermediate plate and the movable plate so that the intermediate plate and the movable plate can be relatively approached and separated, providing a distance bar attached to the movable platen and extending toward the intermediate plate;
When the movable plate and the intermediate plate are brought close to each other by the side cylinder, the distance bar can be inserted into a through hole provided in the intermediate plate, and is further driven by a predetermined driving means. A locking member is disposed between the distance bar and the intermediate plate, and is driven to selectively take a position that allows insertion of the distance bar into the through hole and a position that prevents such insertion. In the state where the lock member prevents insertion of the distance bar, the pressing force from the plurality of main cylinders is applied to the movable platen via the intermediate plate and the distance bar. be.

(Functions and Effects) This type of mold clamping device has the same advantages as hydromechanical mold clamping devices, such as being able to shorten the overall length of the main cylinder and reducing the amount of hydraulic oil used. Since multiple main cylinders are provided and the combined pressing force of the multiple main cylinders is used as the clamping force of the mold, the burden on each main cylinder is lightened and each main cylinder can be made smaller. It becomes possible. Therefore, it becomes possible to easily manufacture the material of the main ram, machining, etc., and it becomes easy to manufacture the main cylinder and, by extension, the entire mold clamping device.

In addition, since multiple main cylinders are provided, it is possible to accommodate the distance bar in the gap between each main cylinder when the mold is opened, and an accommodation hole for accommodating the distance bar can be formed in the main ram. is no longer necessary,
Since the length of the main ram is no longer limited by its accommodation hole, it is possible to make the main ram even shorter than that of conventional hydromechanical type, and in conjunction with the reduction in the diameter of each main ram, It is possible to make the total material weight of the main ram lighter than that of a conventional ram, although it has the same function.

Furthermore, in the mold clamping device according to the present invention, the pressing force of each main cylinder is transmitted to the movable platen via the intermediate plate, so that the pressing force of each main cylinder is effectively used as one pressing force. It also has the advantage of being able to act on the movable platen.

(Example) Hereinafter, in order to clarify the present invention more specifically,
One embodiment thereof will be described in detail based on the drawings.

In FIGS. 1 to 3, reference numeral 10 denotes a stationary plate on which a stationary mold 12 is mounted, and is fixed at one end on a base 14. As shown in FIGS. Further, a cylinder block 16 is fixed to the other end side of the base 14. Four tie bars 18 are arranged parallel to each other to connect the four corners of the fixed platen 10 and the cylinder block 16.

Furthermore, between the fixed platen 10 and the cylinder block 16, a movable platen 22 on which a movable mold 20 is mounted is provided with its four corners slidably supported by tie bars 18, and a movable platen 22 is provided at the bottom. Base 14 in Tashi2124
It is placed on a guide rail 26 disposed above, and is able to slide on this guide rail 26 in parallel to the tie bar 18. Further, an intermediate plate 28 is disposed between the movable plate 22 and the cylinder block 16 and is slidably supported at the four corners by tie bars 18, similarly to the movable plate 22.

As shown in FIGS. 1 and 3, the cylinder block 16 has four main cylinders of the same shape arranged at equal intervals on a concentric circle centered on its center line (the machine axis of the mold clamping device). A cylinder 30 is provided. These main cylinders 30 are all single-acting cylinders, and their main rams 32 are fixed to the intermediate plate 28. A main cylinder chamber 3 is formed behind each main ram 32.
When hydraulic oil is supplied to the cylinder 4, the hydraulic pressure inside the cylinder moves the intermediate plate 28 through the main ram 32 into a movable plate.
22.

As is clear from FIG. 3, the main ram 32 of each main cylinder 30 has a hollow shape with a hollow interior.

Further, the cylinder block 16 is provided with an intermediate disk drive cylinder 36 located in the center thereof, and the intermediate disk drive cylinder 36 moves the intermediate disk 28 toward and away from the fixed plate 10. It has become. That is, the intermediate disk drive cylinder 36 has its piston rod 38 connected to the intermediate disk 28, and its piston is moved by supplying and discharging pressure oil to both oil chambers of the intermediate disk drive cylinder 360 mouth, the door side chamber 40, and the head side chamber 42. When the rod 38 is expanded or contracted, the intermediate plate 28 is moved toward or away from the fixed plate 10 in accordance with the expansion or contraction.

On the other hand, on the intermediate board 28, as shown in FIGS. 2 and 3, two side cylinders 44 are installed on the tie bar 1.
8 and opposite to each other across the machine axis of the mold clamping device at both ends of the intermediate plate 28 in the width direction, and the cylinder tubes 46 of the intermediate plate 2
It is fixed at 8. Each piston rod 48 is connected to the movable plate 22 and has a rod side chamber 50.
By expanding and contracting the piston rod 48 based on the supply and discharge of pressure oil to and from both oil chambers of the head side chamber 52, the intermediate plate 28 and the movable plate 22 are brought closer to each other and separated from each other.

The driving force of the movable platen 22 by these side cylinders 44 is made sufficiently smaller than that of the intermediate plate drive cylinder 36 with respect to the intermediate plate 28.

Furthermore, the cylinder tube 46 and piston 54 of these side cylinders 44 are constructed as shown in FIG. has been effectively alleviated. As will be described later, this reduces the impact when the molds 12, 20 are closed.

That is, as shown in the figure, the inner peripheral portion of the cylinder tube 46 has a small diameter portion 56 over a predetermined length at the end on the rod end side through which the piston rod 48 passes. Ports 58 and 60 are provided at both ends of the portion 56 in the axial direction. It is connected to an electromagnetic switching valve 62, which will be described later, through a port 58 on the head end side, and to a relief valve 64 through a port 60 on the rod end side.

On the other hand, the piston 54 has a small diameter portion 66 at a predetermined length portion on the side to which the piston rod 48 is connected.
As shown in the figure, when moving to the rod end side, the cylinder tube 4
The port 58.6 is oil-tightly fitted into the small diameter portion 56 in the
0 between the piston 54 and the cylinder tube 46.
An oil chamber 68 that communicates only with the port 60 is formed between the rod end side end portion and the end portion of the rod end side.

That is, in this embodiment, an oil chamber 68 is formed between the piston 54 and the end of the cylinder tube 46 on the rod end side near the maximum extension of the piston rod 48, and the oil pressure inside the oil chamber 68 is The pressure in the oil chamber 68 is maintained at a constant pressure or higher by the valve 64, and the impact of the collision between the piston 54 and the cylinder tube 46 when the piston rod 48 is fully extended is reduced. It has become.

Note that a check valve 70 whose forward direction is from the port 58 to the port 60 is provided between the ports 58 and 60, and the piston rod 48
When the oil chamber 68 expands during contraction, pressure oil is supplied into the oil chamber 68 through the check valve 70.

This eliminates the negative pressure within the oil chamber 68, allowing the piston rod 48 to contract smoothly.

Furthermore, as shown in FIGS. 1 and 3, the movable platen 22 has four distance spars 172 erected thereon, extending from its back surface toward the intermediate plate 28 side. These death spas 〒72 are the third
As is clear from the figure, the main cylinders 30 and 4 are arranged at equal intervals on a concentric circle centered on the machine axis of the mold clamping device.
The intermediate plate 28 and the cylinder block 16 are arranged in a gap between the main cylinders 30 with a phase difference of 56, and when the side cylinder 44 is contracted, the intermediate plate 28 and the cylinder block 16
The main cylinders 30 are retracted through correspondingly formed through holes 74 and 76, respectively, and are accommodated in the gap between the main cylinders 30. On the other hand, as shown in FIG. 5, these distance spars 72 have a length that forms a certain gap between the rear end and the plate surface of the intermediate plate 28 when the side cylinder 44 is in its most extended state. When the side cylinder 44 is fully extended, the lock plate 78 provided on the intermediate plate 28 is allowed to enter the gap.

As shown in FIG. 6, this lock plate 78 has a substantially disk shape, and is rotatable and axially connected to a shaft 80 erected at the center of the intermediate plate 28 at its center. movably supported. As shown in FIG. 1, the head 84 of the shaft 80 is always urged in a direction away from the intermediate plate 28 by a compression spring 82 disposed between it and the intermediate plate 28. At the position where it abuts against the head 84 of the shaft 80, as shown in FIG. A certain minute gap is provided between the side cylinder 44 and the rear end of the distance spar 72 when the side cylinder 44 is fully extended.

On the other hand, as shown in FIG. 6, a rotary drive cylinder 86 is connected to the outer peripheral portion of the lock plate 78 through its piston rod 88, and as is clear from FIGS. 6 and 7. According to the expansion and contraction of the piston rod 84, the lock plate 78 can be rotated around the shaft 80 within an angular range of about 456 degrees. When the piston rod 88 is extended, four through holes 90 are formed in the lock plate 78 at positions corresponding to the through holes 74 of the intermediate plate 28, as shown in FIG.
is formed to allow the four death spar 72 to penetrate through each of the through holes 90 and retreat when the piston rond 88 is extended.

Note that this rotary drive cylinder 86 is configured to expand and contract based on the hydraulic oil supplied from the pump 93 by the switching operation of the electromagnetic switching valve 92 . Further, in FIG. 1, reference numeral 94 denotes a plate cover that covers the lock plate 78, and the death spar 72 is disposed through the plate cover 94. moreover,
In FIG. 1, reference numeral 95 is an ejector pin provided on the movable platen 22, which is projected by a drive means (not shown) to release the molded product.

In such a mold clamping device, as shown in FIG. 8, the main cylinder chamber 34 of the main cylinder 30 is
A solenoid switching valve 96 is connected to the solenoid switching valve 96, and supply and discharge of hydraulic oil to and from the main cylinder chamber 34 is controlled by switching control of the electromagnetic switching valve 96.
Supply and discharge of hydraulic oil to and from the rod side chamber 40 and head side chamber 42 of the piston rod 38 is controlled by the electromagnetic switching valve 98, and the piston rod 38 is controlled by the electromagnetic switching valve 98.
can be expanded, contracted, or held in a fixed position. Further, the electromagnetic switching valve 6 is provided in the rod side chamber 50 and the head side chamber 52 of the side cylinder 44.
2 is connected to the rod side chamber 50 and the head side chamber 52 depending on the switching position of the electromagnetic switching valve 62.
0 is shut off, while the hydraulic oil in the head side chamber 52 is allowed to flow out.

In addition, in FIG. 8, 100 is a check valve connected between the main cylinder chamber 34 of the main cylinder 30 and the tank, with the direction from the tank toward the main cylinder chamber 34 being the forward direction. The operation is controlled according to the operating state, and the piston rod 38 of the intermediate plate drive cylinder 36
When the main cylinder chamber 34 is contracted, the main cylinder chamber 34 is communicated with the tank. Also, in the figure, 10
2 is a relief valve for preventing the pressure in the rod side chamber 40 of the intermediate disc drive cylinder 36 from rising above a certain pressure;
This is a variable throttle valve for controlling the flow rate of hydraulic oil discharged from the electromagnetic switching valve 96 from the electromagnetic switching valve 96. Furthermore, 10
Reference numeral 4 denotes a pump, which has a larger capacity and discharge pressure than the pump 93 which serves as the hydraulic pressure source for the rotary drive cylinder 86.

In such a mold clamping device, prior to starting the mold clamping operation,
As will be described later, before the main ram 32 of the main cylinder 30 is extended, and the piston rod 48 of the side cylinder 44
The intermediate plate 28 is moved by the intermediate plate drive cylinder 36 so that the mold closing of the mold 12.20 is completed in the most extended state.
is held in advance at a position corresponding to the thickness of the mold 12.20. After such settings, a mold closing operation is performed from the mold opening state shown in FIGS. 1 and 2. That is, in this mold closing operation, first, the electromagnetic switching valve 62 is switched, and the piston rod 4 of the side cylinder 44 is switched.
8 is extended, and the movable platen 22 is moved to the side cylinder 4.
Fixed plate 10 according to the extension speed of piston rod 48 of 4.
be forced to move at high speed. As a result, the mold 12.20 is closed at high speed. Further, as the movable platen 22 moves, the death spar 72 erected thereon is also moved forward toward the fixed platen 10, and when the piston rod 48 is fully extended, the rear end and the intermediate plate 2
A predetermined gap is formed between the lock plate 8 and the lock plate 78 to allow the lock plate 78 to enter therein.

Note that before the small diameter portion 66 of the piston 54 of the side cylinder 44 fits into the small diameter portion 56 of the cylinder tube 46, the boats 58 and 60 are not isolated, and the hydraulic oil in the rod side chamber 50 is transferred to the boat 58. and solenoid switching valve 6
2, the piston rod 48
Although the extension speed of piston rod 4 does not decrease,
8 reaches just before the maximum extension state, as described above, the boats 58 and 60 are cut off by the small diameter portion 66 of the piston 54, and an oil chamber 68 is formed between the piston 54 and the cylinder tube 46. Since hydraulic pressure is generated in the oil chamber 68 based on the relief valve 64, the extension speed of the piston rod 48 rapidly decreases. In other words, the piston rod 48 moves at high speed during most of its mold closing stroke, but when the piston rod 48 reaches a position just before maximum extension, its operating speed rapidly decreases. Therefore, the piston 54 and the cylinder tube 46
As a result, the molds 12 and 20 are prevented from colliding at high speed, and damage to the molds 12, 20 and the piston rod 48 due to the impact of the collision can be effectively avoided.

When the mold closing operation is completed, the electromagnetic switching valve 92 is switched, and the piston rod 88 of the rotary drive cylinder 86 is closed.
is contracted, and the lock plate 78 is rotated about the shaft 80. By this rotation, as shown in FIG. 7, the through hole 90 of the lock plate 78 is removed from the extension line of the death spar 72, thereby preventing the death spar 72 from retreating. Note that during this rotation, as described above, a gap is formed between the lock plate 78, the intermediate plate 28, and the death spar 72, so the lock plate 78 is attached to the piston rod 88 of the rotary drive cylinder 86. It can be rotated extremely smoothly according to the contraction operation.

Next, in this state, both the electromagnetic switching valves 96 and 98 are switched, hydraulic oil is supplied to the main cylinder chamber 34 of the main cylinder 30, and the main ram 32 is extended.
Hydraulic oil is supplied and discharged to and from the head side chamber 42 and rod side chamber 40 of the intermediate disk drive cylinder 36, the piston rod 38 is extended, and the intermediate disk 28 is moved to the fixed disk 1.
It is moved toward the 0 side. As a result, as shown in FIG. 9, the gaps between the lock plate 78, the intermediate plate 28 and the death spar 72 disappear,
The pressing force based on the main cylinder 30 and the intermediate plate drive cylinder 36 is applied from the intermediate plate 28 to the lock plate 78. It is transmitted to the movable platen 22 via the death spar 72. In other words, the molds 12 and 20 have four main cylinders 30
The molds 12 and 20 are clamped together by the combined pressing force of the intermediate disk drive cylinder 36.
This provides a mold clamping force sufficient to counteract the pressure of the injection resin injected into the product cavity between the molds. Incidentally, when the mold is clamped, the piston rod 48 of the side cylinder 44 is slightly contracted from the maximum extension state, as shown in FIG. 10. Further, as is clear from the above description, in this embodiment, the lock plate 78 constitutes the lock member.

When the molding operation is completed under this clamping state, the electromagnetic switching valves 96 and 98 are switched, and the main cylinder chamber 34 of the main cylinder 30 is connected to the tank, and the rod side chamber 40 of the intermediate disk drive cylinder 36 and The state of supply and discharge of hydraulic oil to and from the head side chamber 42 is reversed, and the intermediate plate 28 is moved back in a direction away from the movable plate 22 as the piston rod 38 of the intermediate plate drive cylinder 36 contracts. When the piston rod 48 of the side cylinder 44 returns to its fully extended state due to the retreat of the intermediate plate 28, the driving force of the intermediate plate drive cylinder 36 is transmitted to the movable plate 22, and the molds 12, 20 are moved. The mold is opened. That is, at this stage, the mold 12.2.0 is opened at a low speed based on the large driving force of the intermediate disc drive cylinder 36.

On the other hand, at this stage of low-speed mold opening, the detection means (not shown) detects that the piston rod 48 of the side cylinder 44 has returned to its fully extended state, and the gap between the lock plate 78, the intermediate plate 28, and the death stamper 72 is detected by the detection means (not shown). When it is again confirmed that a predetermined minute gap as shown in FIG. Then, the lock plate 78 is rotated to a position that allows the death spar 72 to retreat as shown in FIG.

The low-speed mold opening process continues until the movable platen 22 reaches a position where it can be retracted only by the actuation force of the side cylinder 44. When the movable platen 22 retreats to this position, the electromagnetic switching valve 98 is activated by the intermediate plate drive cylinder 36.
The piston rod 38 is switched to a position where it is stopped,
While the movement of the intermediate plate 28 is stopped, the electromagnetic switching valve 62 is switched to a position where the piston rod 48 of the side cylinder 44 is contracted, thereby causing the movable plate 22 to retreat at high speed. In other words, the molds are opened at a high speed of 12 degrees and 20 degrees. Then, in the latter half of this high-speed mold opening stroke, the contraction speed of the piston rod 48 is reduced, and the movable platen 22 is stopped with a predetermined mold opening interval separating the fixed platen 10 and the movable platen 22.

Note that, as described above, hydraulic oil is supplied to the oil chamber 68 of the side cylinder 44 through the check valve 70, so that the inside of the oil chamber 68 becomes negative pressure and the piston rod 4
There is no reduction in the contraction rate of 8. Also, as the movable platen 22 moves backward during this high-speed mold opening stroke, the death spar 72 moves to the lock plate 78. Intermediate board 28. It is retracted through each of the through holes 90 , 74 and 76 in the cylinder block 16 and is received in the gap between the main cylinders 30 .

In this state, the molded product is released from the movable mold 20 by the ejector pin 95, and then the electromagnetic switching valve 9
8, the intermediate plate 28 is returned to the position before the extension operation, and the molding cycle is completed. In other words, since the intermediate plate 28 is slightly moved toward the main cylinder 30 during the low-speed mold opening process, the intermediate plate 28 is returned to the predetermined position before the start of molding, and from this returned state, as described above, The molding operation will be repeated again.

In order to shorten the dry cycle, as described above, the piston loft 48 of the side cylinder 44 is extended without returning the intermediate plate 28 to the predetermined position, and when the piston rod 48 is fully extended, the mold 12.2
Immediately after the mold closing of 0 is completed, the intermediate plate 2 is moved to the state before 3, while the intermediate plate 2 is moved only by the intermediate plate drive cylinder 36
While performing the forward movement of 8 at low speed, the rotary drive cylinder 8
6 to rotate the lock plate 78 to interpose the lock plate 78 between the intermediate plate 28 and the death spar 72, and then extend the main ram 32 of the main cylinder 30 to perform a clamping operation. It is also possible to

As explained above, according to the mold clamping device of this embodiment, the mold opening/closing operation of the mold 12.20 is mainly performed by the side cylinder 4.
4, and the main cylinder 30 is only slightly expanded and contracted during the clamping operation of the molds 12 and 20 and the low-speed mold opening operation. The overall length can be shortened, and the amount of hydraulic oil used can be reduced. Moreover, in this embodiment, four main cylinders 30 are provided, and the load on each main cylinder 30 is extremely light compared to the conventional case where there is only one main cylinder, so the main ram 32 of each main cylinder 30 is The diameter is significantly smaller than that of conventional cylinders, and therefore manufacturing and machining of the material for the main ram 32 is much easier than in the past, making it easier to manufacture the main cylinder 30 and, by extension, the entire mold clamping device. It becomes easier.

Furthermore, a death spar 72 for transmitting the pressing force of the main cylinders 30 to the movable platen 22 is housed in the gap between the plurality of main cylinders 30 when the mold is opened, unlike the conventional hydromechanical type. Like the mold clamping device of
Since there is no need to form an accommodation hole in the main ram 32 to accommodate the death spar 72, the overall length of the main ram 32 is not limited by the formation of such an accommodation hole. The overall length is even shorter than that of conventional hydromechanical types. Additionally, as a result of this, in addition to reducing the diameter of the main ram 32, the total material weight of the entire main ram 32 has become significantly lighter compared to conventional ones with the same function.
In this embodiment, as described above, the total weight of the material of the main ram 32 is also reduced by making the main ram 32 hollow.

Incidentally, it has been confirmed that in the case where four main cylinders 30 are used as in this embodiment, the total material weight of the main ram 32 can be reduced by about 25% compared to a conventional one having the same function.

Further, in the mold clamping device of this embodiment, as described above, the intermediate disk drive cylinder 36 is provided, and the intermediate disk drive cylinder 36 sets the initial position of the intermediate disk 28 before the start of molding, and clamps the mold. The amount of expansion and contraction of the main ram 32 of the main cylinder 30 at the time is independent of the thickness of the mold 12.20,
Since it is designed to be always short, there is also the advantage that the molding cycle can always be shortened well.

Furthermore, since the low-speed mold opening operation at the beginning of the mold opening stroke of the molds 12 and 20 is performed by the driving force of the intermediate plate drive cylinder 36, it is easy to make the side cylinder 44 smaller and faster. There are also some advantages.

Although one embodiment of the present invention has been described above, this is a literal illustration, and the present invention should not be interpreted as being limited to this specific example.

For example, in the embodiment described above, when the piston rod 48 of the side cylinder 44 is fully extended, the mold 12.20 is completely closed, and at the same time as the mold closing is completed, the intermediate plate 28 and the death stamper 72 are closed. Lock plate 78 between
However, when the piston rod 48 is fully extended, the mold 1
The lock plate 78 is placed between the intermediate plate 28 and the death spar 72 in the state immediately before the mold closing is completed.
It is also possible to form a gap that allows the intrusion of.

Further, the lock plate 78 can be provided so as to be rotatable while sliding on the intermediate board 28. Furthermore, by moving the lock plate 78 linearly along the board surface of the intermediate board 28, the destabilization can be performed. It is also possible to selectively take a position where the spar 72 is allowed to retreat and a position where it is blocked.
3 In addition, in the above embodiment, only one intermediate board drive cylinder 36 was provided in line with the machine axis of the mold clamping device, but two intermediate plate drive cylinders 36 were provided at opposite positions across the machine axis. Furthermore, it is also possible to provide such an intermediate plate drive cylinder 36 with only the function of retracting the intermediate plate 28.

Furthermore, in the embodiment described above, four main cylinders 30 and four death spars 72 were each provided, but the number of these cylinders is not limited to this.

In addition, various modifications may be made without departing from the spirit of the present invention, although they are not listed here.

It goes without saying that the present invention can be implemented in a modified form.

[Brief explanation of the drawing]

FIG. 1 is a front cross-sectional explanatory view showing one embodiment of the mold clamping device according to the present invention, FIG. 2 is a cross-sectional view of the principal part thereof, and FIG. It is an explanatory diagram. FIG. 4 is an enlarged cross-sectional explanatory view showing the main parts of the side cylinder shown in FIG. 2 together with a part of the hydraulic circuit. FIG. 5 is a cross-sectional explanatory view for explaining the operating state of the device shown in FIG. 1 at the completion of the mold closing process. 6 and 7 are explanatory diagrams respectively showing the lock plate of the device of FIG. 1 and a rotary drive cylinder for driving the same, together with a hydraulic circuit for driving the rotary drive cylinder, and FIG. Figure 6 shows the rotational position of the lock plate during high-speed opening/closing.
Further, FIG. 7 shows the rotational position of the lock plate during mold clamping. FIG. 8 is a system diagram for explaining the hydraulic circuit of the device shown in FIG. 1. 9 and 10 are views corresponding to FIG. 1 and FIG. 2, respectively, for explaining the operating state of the device shown in FIG. 1 during mold clamping. 10: Fixed plate 12, 20: Mold 22: Movable plate 28: Intermediate plate 30: Main cylinder 32: Main ram 36: Intermediate plate drive cylinder 44: Side cylinder 72: Death stamper 74.7
6.90: Through hole 78: Lock plate (lock member) 82: Compression spring 86: Rotation drive cylinder

Claims (1)

[Scope of Claims] A mold clamping method for an injection molding machine in which a movable platen is moved relative to a fixed platen, thereby performing mold opening/closing operations and clamping operations of a mold between the movable platen and the fixed platen. In the apparatus, an intermediate plate is movably arranged behind the movable plate,
The intermediate plate can be moved by a plurality of main cylinders, and a side cylinder is provided between the intermediate plate and the movable plate, so that the intermediate plate and the movable plate can be relatively approached and separated. while being attached to the movable platen,
A distance bar extending toward the intermediate plate is provided, and when the movable plate and the intermediate plate are brought close to each other by the side cylinder, the distance bar is inserted into a through hole provided in the intermediate plate. do what you can,
Further, a locking member is provided between the distance bar and the intermediate plate, which is driven by a predetermined driving means to selectively take a position that allows insertion of the distance bar into the through hole and a position that prevents such insertion. and a pressing force from the plurality of main cylinders acts on the movable platen via the intermediate plate and the distance bar when the locking member prevents insertion of the distance bar. A mold clamping device for an injection molding machine.