JPH0113407B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a mold clamping device for an injection molding machine.

(Prior art) A so-called two-cylinder type mold clamping device in which the opening and closing of the mold and the mold clamping are performed using separate cylinders are disclosed in Japanese Patent Application Laid-Open No. 1983-1999.
It is known from Publication No. 49239.

This conventional technology uses a fixed plate (base) with a fixed mold, and multiple tie rods (tie bars).
A tie rod is inserted into the slide (moving plate) that supports the movable mold, and a nut is screwed into the threaded part of the tie rod to receive the mold clamping reaction force. It is equipped with an opening/closing cylinder and a mold clamping cylinder.

(Problems to be Solved by the Invention) In the prior art described above, the tie rod and the mold clamping cylinder are arranged side by side in the horizontal direction, so the size is large in the horizontal direction, and the thickness of the mold used is The problem is that it is easily subject to restrictions.

Another problem is that the threaded portion can only be adjusted to the same thickness as the nut, and the mold thickness can only be adjusted by the stroke of the mold clamping cylinder.

The present invention provides an engaging portion on the outer circumferential surface of the portion of the tie rod that protrudes from the base to guide the movement of the slide, and that protrudes from the slide toward the side opposite to the base when the mold is closed, and engages when the mold is closed. By providing a locking member that can be engaged with and removed from the tie rod through the section and slidable in the axial direction of the tie rod, and by providing a clamping cylinder between the locking member and the slide, it can be made more compact in the lateral direction. It is an object of the present invention to avoid restrictions on mold thickness by separately providing adjustable lock positioning means.

(Means for Achieving the Object) The present invention opens and closes the mold by moving a slide supporting a movable mold in directions toward and away from a base supporting a fixed mold using an opening/closing cylinder. A mold clamping device for an injection molding machine is equipped with a mold clamping cylinder that clamps the mold when the mold is closed, and a tie rod that protrudes from the base to guide the movement of the slide. An engaging portion is provided on the outer circumferential surface of the portion protruding toward the side opposite to the base, and a lock member that can be engaged with and disengaged from the tie rod through the engaging portion when the mold is closed is provided so as to be slidable in the axial direction of the tie rod. A mold clamping cylinder is interposed between the tie rod and the slide via a common lock plate, and a rod of lock positioning means having an axis parallel to the axial direction of the tie rod is inserted through the lock plate. , the rod is provided with a stopper that can engage with the lock plate and is movable and adjustable in the axial direction of the rod.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments. FIG. 1 shows an example of the apparatus of the present invention implemented in a vertical injection molding machine, in which a fixed mold 2 is installed on a base 1. On the base 1, four tie rods 3 (only two are shown in the figure) are installed in parallel in the diagonal direction that surrounds the mold 2 and passes through the center of the mold. A support plate 4 is installed in common at the upper end of each of the tie rods 3, and a slide 5 is installed to be able to move up and down freely over these tie rods 3. A movable mold 6 is installed on the slide 5 in correspondence with the fixed mold 2. The piston rod 7a of the mold opening/closing cylinder 7 installed on the base 1 side is connected to the slide 5.
By being connected to the slide 5, the slide 5 is moved up and down toward the base 1, and the movable mold 6 is opened and closed relative to the fixed mold 2.
The injection plate 8 has a drive cylinder 9 and a guide rod 1.
0, both of which belong to a structure known as an injection molding machine. In such a molding machine, in the present invention, the fixed mold 2 of each tie rod 3 is
A locking engagement portion 1 is provided on the outer circumferential surface at the upper side.
1, and its engaging part structure is a continuous formation of grooved tooth surfaces as shown in FIG. 7, or a screw (not shown), etc. As shown in FIG. 1, it is assumed to stop within a predetermined length in the axial direction. This engaging part 11
On the other hand, a lock member 12 is provided on the tie rod 3 so as to be slidable in the axial direction and to be freely engageable and detachable from the engaging portion 11. As shown in the first figure, the lock member 12 is housed in a casing 12a that surrounds the outer periphery of the tie rod 3 and allows the tie rod 3 to pass through.
As shown in FIG. 7, a semicircular engagement surface 11a surrounds each half of the tie rod 3 and is removable from the engagement portion 11 formed by the grooved tooth surface of the tie rod 3. It consists of a pair of divided lock pieces 13 and 14 which are formed symmetrically, and these divided lock pieces 13 and 14 are arranged, for example, in the drive cylinder 1.
5. The piston rods 15a and the like can be moved forward and backward toward the center of the tie rod through a forward and backward mechanism such as the piston rod 15a, so that they can be locked with the tie rod 3 through the engagement and disengagement of their grooved tooth surfaces.
Of course, the structure of this engaging portion 11 and locking member 12 is as follows.
This is just an example in which both can be locked in a detachable manner, and design changes are of course possible. In the present invention, each lock member 12 provided slidably and lockably on each of these tie rods 3 has its casing 12a attached to a common lock plate 1 as shown in the figure.
The lock plate 16 is integrally supported by being fixed to the upper surface of the tie rod 6, and the lock plate 16 is fitted loosely and slidably over each tie rod 3. Between the lower surface of the lock plate 16 that commonly supports each lock member 12 and the upper surface of the slide 5 described above, mold clamping cylinders 17 are interposed at positions corresponding to the lock members 12, respectively. The main body side is fixed to the upper surface of the slide 5, and the piston rod 1 of the cylinder 17
7a is connected to the lock plate 16. In this connection, the piston rod 17a and the lock plate 16 are directly fixed, but as illustrated in FIG. It has the same effect even if it is fixed freely. Further, the mold clamping cylinder 17 is of a single-acting type, and as shown in the figure, the tie rod 3 is inserted through the center, and is equipped with a return packing 20, a port 21, etc. Furthermore, in the present invention, a positioning device 22 as illustrated in FIG. 1 and FIGS. 5, 6, and 8 is provided as means for locking and positioning the lock plate 16. The example shown in FIG. 5 is one in which positioning is performed simultaneously on two tie rods 3, 3 in the diagonal direction, and the device 22 is provided using a support plate 4. As shown in FIGS. 5 and 6, a drive motor 23 installed on the plate 4 rotates a pair of vertical drive shafts 27 and 27 in forward and reverse directions from a drive horizontal shaft 26 via a transmission member such as a bevel gear 25. Stoppers 28, 28 (using screw nuts) are attached to the screw screws 27a, 27a provided at the lower part of the drive vertical shafts 27, 27, and engaged with the guide elongated hole 29a of the guide tube 29 that envelops the vertical shaft 27. By screwing the convex elements 28a together so that they can rise and fall freely, the stopper 2
8 is moved up and down to a desired position, and the lock plate 16 is supported by the stopper 28. 30 is a rotary cam switch, which is used to check whether the engaged state is safe or unsafe when the engaging surface 11a of the engaging portion 11 is a grooved tooth surface as shown in FIG. , the switch 31 is turned off when the situation is safe and the switch 31 is turned on when the situation is not safe. A cutout 33 corresponding to a safety margin is provided on the circumferential surface of the cam 32 as shown in FIG. This fifth,
In the device 22 shown in Figures 6 and 8, the positioning of the lock plate 16 is performed simultaneously on two diagonal tie rods 3, 3, but this is done only on one tie rod 3. In this case, it is sufficient to simply connect the motor 23 and the rotary cam switch 30 to the driving vertical shaft 27 as shown in FIG.

According to the mold clamping device according to the present invention, positioning of the lock plate 16 via the positioning device 22 and mold clamping are performed as follows.

Now new mold 2 on base 1 and slide 5,
The lock position is determined as follows when replacing and installing 6. That is, the drive motor 23 of the positioning device 22 is driven to rotate its drive vertical shaft 27 to lower the stopper 28 to the lowest position, and then the slide 5 is lowered by driving the mold opening/closing cylinder 7. After tightly closing the movable mold 6 to the fixed mold 2, the drive motor 23 of the positioning device 22 is driven, and the drive vertical shaft 27 is reversed to raise the stopper 28 that has been lowered to the lowest position. (The motor 23 was used here, but it may also be done manually). At this time, after confirming that the stopper 28, which has been raised by a known torque limiter or load cell (not shown), has come into contact with the lower surface of the lock plate 16, which has descended along with the descent of the slide 5, the position of contact has been confirmed. The rotary cam switch 30 is used to confirm whether or not the lock member 12 and the engaging portion 11 of the tie rod 3 are safely and securely engaged within the lock safety range. That is, if the engaging portion 11 and the semicircular engaging surfaces 11a of the locking pieces 13 and 14 are engaged within the range shown by diagonal lines in FIG. In region a, the defect 33 corresponding to the safety range a in the cam 32 of the rotary cam switch 30 comes to the switch 31 position through the rotation of the driving vertical shaft 27, so the movement on the vertical shaft 27 side is stopped at this stage. This completes the initial setting of the stopper 28. If the engaged state is not in the safe and certain area a, it is in the lock danger area, so the piston rod 17a in the mold clamping cylinder 17 rises,
Along with this, the stopper 28 rises again due to the load reduction of the torque limiter, load cell, etc., and as a result of this rise again, when the switch 31 on the rotary cam switch 30 side comes to the notch 33 corresponding to the lock safety area a. , piston rod 1 on the spot
7a and the positioning device 22 are stopped, and the initial setting is completed. In this way, the first lock position is determined when using new molds 2, 6.

After setting the positioning stoppers 28 in the new molds 2 and 6 in the appropriate positions as described above, the injection molding operation begins. 7 to the highest position, the mold clamping cylinder 17, lock plate 16, and lock member 12 all rise together, and from this starting position, although not shown, the drive cylinder 7 is opened with the release of the fall prevention block. By operating, the slide 5 moves through a low-speed descent from the start position, an intermediate high-speed descent, and a low-speed descent before the molds 2 and 6 come into contact, resulting in the state shown in FIG. 2 before the molds come into contact. At this point, the lock plate 16 is stopped by being stopped by the stopper 28 set in advance, and since this stopping position is the lock position, the pair of split lock pieces 13 of each lock member 12 located on the lock plate 16 are locked. , 14 are the respective drive cylinders 15
Through the movement of the piston rod 15a, a locking action is started in which the semicircular engaging surfaces 11a, 11a engage with the outer circumferential surface (grooved tooth surface, etc.) of the engaging portion 11 of the tie rod 3. During this locking operation of the locking member 12, the mold opening/closing cylinder 7
The slide 5 and the mold clamping cylinder 17 continue to descend until the movable mold 6 comes into close contact with the fixed mold 2. In this way, the molds 2 and 6 are tightly closed as shown in FIG. 3, and the lock member 1 is already closed.
2 and tie rod 3 engaging part 11 divided lock piece 1
Since the engagement lock by steps 3 and 14 has been completed,
Upon completion of this close contact with the mold, the supply of pressure oil for mold clamping into the mold clamping cylinder 17 is started. This third
In the figure, a gap is shown between the lock plate 16 and the piston rod 17a of the mold clamping cylinder 17, but this is due to the fact that the lock plate 16 and the piston rod 17a are connected to the bolt 18 spring illustrated in FIG. 19, the lock plate 16 and the piston rod 1
If 7a were directly fixed, a similar gap would exist between the lower end of piston rod 17a and the bottom of clamping cylinder 17.

In this way, by supplying the mold clamping pressure oil into the mold clamping cylinder 17, the mold clamping pressure increases as shown in FIG. Tie rod 3 integrated through
As a result, a strong mold clamping force is generated on the mold 2 and 6 sides through the mold clamping cylinder 17 slide 5, and the mold retightening begins. Known injection molding can be smoothly performed. When opening the mold after injection molding, the pressure in the mold clamping cylinder 17 is reduced to lower the piston rod 17a, and the lock plate 1 is lowered.
The engagement lock is released by moving the pair of split lock pieces 13 and 14 of each lock member 12 on the lock member 6 backward from the engagement part of the tie rod 3, and then the slide 5 is released by the operation of the mold opening/closing cylinder 7. The robot first rises at a low speed, then rises at an intermediate high speed, and then stops rising after a final slow rise, and then returns to the starting position shown in FIG. 1 by engaging the fall prevention lock.

In the mold clamping device of the present invention, as described above, each lock member 12 for generating mold clamping force in each tie rod 3 is installed on a common lock plate 16 and separated from the slide 5, and Since the locking position of the locking member 12 is appropriately set by a separately provided adjustable positioning device 22, the correct locking position of the locking member 12 can be
It is determined automatically and mechanically, and its reproducibility and reliability are extremely improved. Moreover, since the locking operation is completed during the low-speed descent before the mold comes into contact, it is no longer necessary to perform locking work as before. Cycle time can be shortened without wasting time, and it is reliable and easy to correctly lock a plurality of locking members 12 at the same time. In addition, the lock plate 16 is stopped at an appropriate position by the positioning device 22 regardless of the mold dimensions (thickness),
Therefore, the thickness of the mold used (within the specified value range) can be of any size, and it is easier to operate than conventional mold clamping devices, and it also provides more effective mold clamping. In addition, a locking member is provided on the tie rod via a locking plate, and a mold clamping cylinder is provided between this locking member and the slide, so it is different from the conventional example in which the locking member and mold clamping cylinder are installed side by side. Not only can it be made more compact in the lateral direction than that, there are fewer restrictions on the thickness of the mold used, and it is also possible to incorporate an injection plate, etc., which is a means of supplying injection material to the mold.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view of the main part showing the embodiment of the present invention device at the starting position, Fig. 2 is a longitudinal sectional front view of the same main part before the mold is brought into close contact with the mold, and Fig. 3 is the same main part when the same mold is brought into close contact with the mold. 4 is a longitudinal sectional front view of the same main part during mold clamping pressure increase, FIG. 5 is a plan view of an embodiment of the positioning device, FIG. 6 is an explanatory diagram of the device drive structure, and FIG. 7 is the same lock. FIG. 8 is an explanatory diagram of the main parts of the rotary cam switch, and FIG. 9 is a sectional side view of the main parts of the lock plate and mold clamping piston rod connection structure embodiment. 1...Base, 2...Fixed mold, 3...Tie rod,
5... Slide, 6... Moving mold, 7... Mold opening/closing cylinder, 11... Engaging portion, 12... Lock member, 16... Lock plate, 17... Mold clamping cylinder, 22... Positioning device, 28... Stopper.

Claims (1)

[Claims] 1. The slide supporting the movable mold is moved toward and away from the base supporting the fixed mold by an opening/closing cylinder to open and close the mold, and the mold is clamped in the mold closed state. In a mold clamping device for an injection molding machine, the mold clamping cylinder is equipped with a mold clamping cylinder that moves the slide, and a tie rod that protrudes from the base to guide the movement of the slide. An engaging part is provided on the outer circumferential surface of the part, and a lock member that can be engaged with and disengaged from the tie rod through the engaging part when the mold is closed is provided so as to be slidable in the tie rod axial direction, and the tie rod is connected between the lock member and the slide. A mold clamping cylinder is interposed on the top via a common lock plate, and a rod of a lock positioning means having an axis parallel to the axial direction of the tie rod is inserted through the lock plate, and a lock is attached to the rod. A mold clamping device for an injection molding machine, characterized in that a stopper is provided that can engage with a plate and is movable and adjustable in the axial direction of the rod.