JPH02281908A - Die locking device of die head for blow molder - Google Patents

Abstract

PURPOSE:To efficiently perform the replacing operation of a die and at the same time prevent the uneven locking from occurring over the whole periphery of the die by a method wherein each piston rod is made possible to be reciprocated between its forward locking end to abut against a tapered face and its backward opening end to release said abutment. CONSTITUTION:The reciprocating direction of each piston rod 22 is the radial direction of a die ring 12. To the tip of the piston rod 22, a wedge 23 formed by a tapered face 24 is integrally mounted. A part of each wedge 23 is made slidable against the guide groove 15 of a die head main body 14. A tip piece 16 having a tapered face 16a, which is abutable against the tapered face 24 of the wedge 23, is detachably mounted to the part of the lower edge face near the outer periphery of the die ring 12. The wedge 23 is made to reciprocate between its forward locking end, at which both the tapered face 16a and 24 abut against each other, and its backward opening end, at which said abutment is released. Thus, the die ring can easily be attached to and detached from the die main body.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention (Field of Industrial Application) The present invention relates to a die locking device in a die head for blow molding, which allows a die ring to be easily attached to and detached from a die body.

<Conventional technology> Generally, in die heads for blow molding machines, the dimensions of the die ring and core are determined by the molded product (mold), so in the case of high-mix, low-volume production, the die ring and core must be replaced frequently. It will be done.

<Problems to be Solved by the Invention> Since the die ring and core are subjected to extra high pressure during blow molding, they are formed thickly to increase rigidity, and are attached using a large number of bolts. Blow molding of large molded products such as heavy-walled bathtubs and car bumpers also increases the weight, and replacement work requires a great deal of labor and time.

On the other hand, there is a die locking device that does not use bolts, as disclosed in Japanese Utility Model Publication No. 61-40498, and the gist of the patent is, as claimed in the utility model registration, that a ring is attached to the lower part of the housing of the parison head body so as to surround the die mounting position. While fixing the members, a number of lock pins each having a cam roller at one end are attached to the ring member so that the other end of the lock pin can engage with the flange portion of the die when the other end of the lock pin protrudes inward of the ring member. A cam ring for moving the lock pin is rotatably disposed through the ring member so as to be movable in a radial direction, and has a tangential cam groove provided on the outer periphery of the ring member to fit correspondingly to each of the cam rollers, and further This die locking device for a parison head for blow molding is characterized by being equipped with a rotating device for the cam ring, but in this device, a large number of lock pins can be simultaneously moved through a ring member by one rotating device and a cam ring. Because the die ring is moved to a different position, the overall dimensions of the die ring are larger than those using bolts, and the tightening force is uneven among all the lock pins due to dimensional temperature differences between each lock pin and play in the pivot. When discharging the parison after locking, there is a risk that the molten resin may leak locally at locations where the clamping force is weak.

This invention does not require a particularly large number of bolts, has a simpler structure than the die locking device described in the prior art publication, allows die replacement work to be performed efficiently, and does not cause uneven tightening around the entire circumference. The purpose of the present invention is to provide a die locking device that does not occur.

1. Structure of the Invention (Means for Solving the 8 Problems) In order to solve the above problems, the present invention provides a structure in which a die ring forming a parison annular discharge port together with a conical core at the tip of a mandrel can be freely attached to and detached from the die head body. In a die locking device for a fixed die head for a blow molding machine, a plurality of reciprocating hydraulic cylinder devices for tightening are provided at equal angular intervals on the outer peripheral surface of the die head body, and the piston rod of each cylinder device is attached to the die head body. It is equipped to move forward and backward in the radial direction, and a structure is provided at the tip of each piston rod, which has a tapered surface that can freely come into contact with the tapered surface formed on the lower end surface of the die ring. This is a die locking device for a die head for a blow molding machine, which is capable of reciprocating between a forward tightening end where a tapered surface contacts and a retreating open end where this contact is released.

The number of the fluid pressure cylinder devices is 6 to 10, and it is desirable to provide a control device that synchronizes and controls the drive of the fluid pressure cylinder devices that tighten the die ring in opposition to each other.

In some cases, a die head for a blow molding machine is used for molding composite materials.

(Function) Next, the function of the die locking device of the present invention constructed as described above will be explained along with its usage method.

(Assembling the die ring to the die head body) In this case, first support the die ring to be assembled from below using a support device such as a jack, and place the die ring under the die head body in a direction corresponding to the axis of the die head body. set.

In this state, the plurality of fluid pressure cylinder devices are operated, each piston rod is advanced toward the die ring, and the tapered surface of the structure at the tip of each piston rod is brought into contact with the tapered surface of the die ring. As it moves forward, the die ring is pressed against the lower end surface of the die head main body and fixedly held in this state. In this state, the supporting force of the supporting device is released.

Before or after this die ring installation operation, a conical core is conventionally bolted to the lower end of the mandrel to obtain the desired die head.

Disassemble and repair the die head assembled in this way.

When cleaning, perform the assembly procedure in reverse order.

That is, after removing the core from the lower end of the mandrel, a support device is set below the die ring, and the die ring is supported from below.Then, the fluid pressure cylinder device is operated,
The piston rods are retreated in a direction away from the die ring, the wedge action of the structure of each piston rod is released, and the force that presses and fixes the die ring against the die head body is released. In this state, the die ring is transferred onto the support device, the die ring is removed from the die head main body, and the molten resin path in the die head is cleaned with the core and die ring removed.

(Example) Next, typical embodiments of the invention will be described.

In FIG. 1, A is a die head for blow molding,
This die head A has a conical core 11 forming a parison annular discharge port 10 and a die ring 12, and this conical core 11 is detachably attached to the tip of a central mandrel 13 of this die head A with a bolt. The die ring 12 is detachably fixed to the die head body 14 by a die locking device [B].

In this die locking device ffB, a plurality of (preferably about 10) hydraulic cylinder devices 20 are installed in the die head A.
They are arranged at equal angular intervals on the outer circumferential surface of.

The cylinder portion 21 of each hydraulic cylinder device 20 is bolted to the die head body 14, and the piston rod 2
The forward and backward reciprocating direction of the piston rods 2 is the radial direction of the die ring 12, that is, the radial direction of the die head A, and the tip of each piston rod 22 has a structure formed with a tapered surface 24 whose upper surface is lowered inwardly. 23 are integrally attached, and a portion of each structure 23 is slidable in the guide groove 15 of the die head main body 14.

A tapered surface 16 that can freely come into contact with the tapered surface 24 of this structure 23
A chip piece 16 having a mark a on the lower surface is detachably attached to a part of the lower end surface of the die ring 14 near the outer periphery.

The structure 23 is capable of reciprocating between a forward tightening end where the tapered surfaces 16a and 24 abut each other and a retreating open end where this contact is released.

The operation of the above embodiment will be explained next.

First, the die ring 1 with the chip piece 16 attached to a predetermined location.
2 is supported from below by a jack concentrically with the die head body 14, and the chip piece 16 of the die ring 12 is
The tapered surface 24 of the structure 23 is lifted up with a jack to a height position between the forward tightening end position and the track.

Next, each of the hydraulic cylinder devices [1t20 is operated to extend each piston rod 22, and these rods 2
Each structure 23 at the two tips is moved from the backward open end to the forward tightening end.

At these forward tightening ends, the tapered surface 24 of each structure 23 is attached to the die ring 12.
Due to the imitation of the structure 23, the die ring 12
The upper end surface of the die head body 14 is pressed and fixed.

At this time, in order to prevent the hydraulic pressure of the hydraulic cylinder device 20 from returning to the return oil path, the switching valve is closed or a check valve is provided.

In this way, before or after the die ring 12 is attached to the die head body 14 by the operation of each hydraulic cylinder device 20, the conical core 11 is attached to the tip of the central mandrel 13,
This core 11 and die ring 12 form a parison annular discharge port 10, and the assembly of the die head A for blow molding is completed.

When disassembling this die head A for repair or cleaning, the assembly procedure is reversed.

In addition, if the tapered surface 16a of the tip piece 16 or the tapered surface 24 of the structure 23 is worn out and becomes unusable due to use, remove the tip piece 16 from the die ring 12 or the structure 23 from the piston rod 22 and replace it with a new one. replace something.

An example of the above-mentioned jack is shown in FIGS. 4 and 5.

In FIGS. 4 and 5, reference numeral 25 denotes a screw type jack, which swings in a horizontal plane around a vertical axis 26 at its base on a frame D□ of an extrusion molding machine having an extrusion nozzle to which the die head A is attached. This jack 25 is attached to the tip of a freely provided swinging arm 27 so as to be able to move up and down.

The screw-type jack 25 is operated by reciprocating the lever, and the lever operation activates the ratchet mechanism (
The feed screw rod 27 is fixed to the case 30 immovably in the axial direction.
A receiving collar 29 for supporting the die ring 12 is attached to the upper end of a support rod 28 which is screwed into the support rod 28 and is movable up and down in the axial direction.

The tip of the swinging arm 27, that is, the screw type jack 25, is located between the hanging position of the die ring crane on the outside of the die head A and the storage position where it is stored along the frame B, passing directly under the die head A. This swinging arm 27 is provided to move in a circular trajectory.

The receiving tsuba 29 has two horizontal support pieces 29a in a cross shape,
29b, and these supporting pieces 29a.

29b are relatively displaced around the vertical bins so that they take a perpendicularly crossed posture when in use, and are set parallel to each other along the frame DL of the extrusion molding machine when not in use. It is provided so that it can be fixed freely.

This jack 25 is first set at a crane hanging position, then the die ring 12 is taken off at this position, and the jack 25 is set directly below the die head A by swinging around the vertical axis 26 of the swinging arm 27. Next, the jack 25 is operated to lift the die ring 12 as described above, set it at the same height as the structure 23, and use it to attach it to the die head body 14.

When not in use, the support pieces 29a and 29b are stacked on top of each other and stored parallel to the frame of the extrusion molding machine with the support pieces 29a and 29b positioned on the longitudinal axis of the swing arm 27.
(See Figure 5).

C1 Effects of the Invention The die locking device of the present invention, which is constructed and operates as described above, is used in a blow molding machine that removably fixes a die ring that forms a parison annular discharge port together with a conical core at the tip of a mandrel to a die head main body. In the die locking Ml of the die head.

A plurality of reciprocating fluid pressure cylinder devices for tightening are provided at equal angular intervals on the outer peripheral surface of the die head body, and the piston rod of each cylinder device is equipped to be movable in the radial direction of the die head body. A body is provided at the tip with a tapered surface that can freely come into contact with the tapered surface formed on the lower end surface of the die ring, and this piston rod has a forward tightening end where these tapered surfaces come into contact, and a body where this abutment This is a die locking device for a blow molding machine die head that can reciprocate between the retracted open end and the released end.
By reciprocating the piston rod of each fluid pressure cylinder device linearly in the radial direction of the die ring, the die ring can be quickly and quickly assembled and disassembled from the die head body, and the die ring can be attached and detached. Since the structure for the die ring is attached to the tip of this piston rod, the structure of the locking device can be simplified without using any drive link mechanism such as a cam ring, and the fixing force of the die ring can be reliably exerted in all structures. I can do it.

According to the second aspect of the present invention, the opposing hydraulic cylinder devices operate synchronously.

The forces that act in the diametrical direction of the die ring during tightening are canceled out, and there is no action to move the die ring in the diametrical direction, thereby stabilizing the installation work, and only the force in the tightening direction acts on the die ring.

(Effect unique to the embodiment) Tapered surface 16a on which the tapered surface 24 of the structure 23 approaches and separates
By removably attaching the chip piece 16 having a shape to a part of the lower end surface of the die ring 12, if the chip piece 16 is worn out or damaged when the die ring 12 is attached to the die head body 14, , it is only necessary to replace this chip piece 16, and the usage period of the die ring 12 can be extended.

When the jack 25 is used, during normal blow molding, the jack 25 is retracted from directly below the blow head A and moved to the frame D of the extrusion molding machine.

Since they are stored parallel to each other, they do not interfere with blow molding, and when replacing or assembling the die ring 12, the swing arm 27 can be pulled out as described above and moved between the crane hanging position and directly below the die head A. This allows the die ring 12 to be easily carried in and out of the die head main body 14.

[Brief explanation of drawings]

The figures relate to this invention, and Fig. 1 is a schematic diagram of a die head for a blow molding machine equipped with a die locking device according to an embodiment of the invention, and Figs. 2 and 3 show a die ring attached to a die ring main body. FIG. 4 is a partially cutaway side view showing an example of the jack used during the first disassembly of the assembly, and FIG. 5 is a plan view thereof. Main symbols in the diagram B...Die locking device, 23...Structure 6.

Claims (1)

[Scope of Claims] 1) In a die locking device for a die head for a blow molding machine that removably fixes a die ring formed by a parison annular discharge port together with a conical core at the tip of a mandrel to the die head body, the outer circumferential surface of the die head body A plurality of reciprocating fluid pressure cylinder devices for tightening are provided at equal angular intervals on the holder, and the piston rod of each cylinder device is equipped to move back and forth in the radial direction of the die head body. A structure is provided with a tapered surface that can freely come into contact with a tapered surface formed on the end surface, and these piston rods have a forward tightening end where these tapered surfaces come into contact, and a retreating end where this contact is released. A die locking device for a die head for a blow molding machine that can reciprocate between the open end and the open end. 2) The number of the fluid pressure cylinder devices is 6 to 10, and a control device is provided to synchronously drive and control the fluid pressure cylinder devices that tighten the die ring in opposition to each other. die locking device for die head for blow molding machines. 3) A die locking device for a die head for a blow molding machine according to claim 1, wherein the die head for the blow molding machine is for molding composite materials.