JP2565100B2 - Rotary extrusion blow molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary extrusion blow molding machine in which the opening and closing of a mold and the vertical movement thereof are performed by a single drive unit.

[0002]

2. Description of the Related Art In a rotary type extrusion blow molding machine, a plurality of molds are arranged at equal intervals on a rotary table, and heat is applied from an extruder die to an open mold located at the bottom of the extruder. Hollow molded products such as bottles are molded by extruding plastic molten resin (parison), then closing the mold, blowing air into the mold while rotating the rotary table, and cooling. . In this case, the thermoplastic molten resin is extruded into the mold and cut by the cutter after the mold is closed, but since the molten resin is still extruded from the extruder die after cutting, the upper part of the mold However, there is a problem that molten resin accumulates.
Therefore, conventionally, after the mold is closed, the die of the extruder is raised or the mold is lowered so that the molten resin is not accumulated on the upper part of the mold.

A rotary extrusion blow molding machine which adopts a conventional method of lowering a mold device will be described with reference to FIG. The extrusion blow molding machine shown in FIG. 5 is a horizontal type, and a plurality of six mold devices 40 are arranged at equal intervals on the upper part of the horizontal rotary table 1. The rotary table 1 can be rotated by a predetermined angle by a driving means (not shown) to extrude a molten resin into a mold, supply compressed air to the mold, and take out a molded product from the mold. I am trying.

The mold device 40 includes molds 41a and 41b,
The mold mounting bases 42a and 42b, the base 43 that movably supports the mold mounting bases 42a and 42b in the horizontal direction, and the rotary table 1 are provided to horizontally mount the mold mounting bases 42a and 42b. To move the mold 41
A drive unit (not shown) that opens and closes a and 41b, and a base 43 (metal molds 41a and 42a, metal mold mounting bases 41b and 4) mounted on the rotary table 1 via an operating rod 45
2b) is vertically moved, and a transmission link 46, an intermediate member 47, a transmission rod 48, and a transmission link 49 for transmitting the motion from the drive unit (not shown) to the die mounting base 42.

The rotary extrusion blow molding machine having such a structure operates as follows. That is, the mold apparatus that moves to the lower side of the extruder 2 by the rotation of the rotary table has the entire apparatus in a raised position and the mold is in an open state, and is extruded from the die 2a of the extruder 2. The incoming molten resin is received between the molds (state A in FIG. 5). Next, in order to mold the hollow molded article by supplying air into the mold and cooling it, the mold is closed and the rotary table 1 is rotated and moved from the lower position of the extruder. At this time, in order to prevent molten resin from accumulating on the upper part of the mold, the mold is lowered (state B in FIG. 5). Cylinder 4
4, the whole mold apparatus is lowered.

[0006]

As described above, as a method for preventing the molten resin from accumulating on the upper part of the mold after the mold is clamped,
There are a method of raising the die of the extruder and a method of lowering the die. However, in the former method of raising the die of the extruder, moving only the die with respect to the fixed extruder makes the joining structure of the extruder and the die very complicated and also causes the flow resistance of the molten resin. There was a problem such as increasing. In the latter method of lowering the mold, the vertical movement of the mold and the opening / closing operation of the mold are performed by separate driving units,
Moreover, since the transmission link 46 for opening and closing the mold, the intermediate member 47, the transmission rod 48, the transmission link 49 and the like are moved up and down together with the mold, the device becomes complicated and the vertical movement The mass of the moving member increases,
There is a problem that the driving means for vertical movement must use a correspondingly large size, which also leads to an increase in size of the entire apparatus.

The present invention has been made in view of the above circumstances, and allows a single drive unit to move the mold up and down and to open and close the mold, and at the time of moving the mold up and down, the mold and the mold mounting base. By only moving up and down,
It is an object of the present invention to provide a rotary type extrusion blow molding machine that can be simplified and downsized.

[0008]

In order to achieve the above object, a plurality of molds are arranged on a rotary table, a thermoplastic molten resin is extruded from the extruder into the molds, and then the molds are removed from the extruder. The rotary extrusion blow molding machine of the present invention which is separated is a base that supports the mold so as to be openable and closable, drive means that moves the base up and down, and one end of which is directly or indirectly attached to the rotary table. Then, the other end is pivotally attached to the mold, and has a link member that opens the mold when the mold rises and closes the mold when the mold descends. The mold is configured to be provided via a mounting base that is axially attached to the other end of the link member that moves on the base, and / or one end of the link member is a drive means such as a hydraulic cylinder that is mounted on the rotary valve. It is configured to be pivoted on.

[0009]

According to the rotary extrusion blow molding machine having the above structure, when the mold is moved up and down by the driving means,
At the same time, the mold is opened and closed, and if necessary, the mold is lowered to close the mold, and then the mold is clamped by the auxiliary drive means.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a schematic plan view showing an embodiment of a horizontal rotary extrusion blow molding machine, FIG. 2 is a front view in which a part is omitted and a main part is cut away, and FIG. 3 is an enlarged description of the main part. It is a figure. The rotary table 10 is shown in FIG.
As shown in FIG. 1, it is rotatably provided on the base 11 and is rotated by the motor 12 in the direction of the arrow in FIG. In the case of the present embodiment, substantially U-shaped housings 14 are arranged at equal intervals at six positions in the circumferential direction of the rotary table 10.

The mold device 20 is located in the housing 14, and includes the mold 21 (21a, 21b) and the mold 21 (2).
1a, 21b) mounting base 22 (22a, 22)
b) and a base 23 for movably supporting the mounting base 22 (22a, 22b) by a slide path 24 provided in the radial direction of the rotary table 10. The base 23 is connected to the cylinder 30 fixed to the rotary table 10, and by the operation of the cylinder 30, the base 23 moves up and down while being guided by the guide shaft 31. Further, the mold device 20 has parallel link members 25 (25a, 25b) for opening and closing the mold 21, and one link member 25a has one end axially attached to the mounting base 22a and the other end. The link member 25b is pivotally attached to the inner wall of the housing 14, and the other end of the link member 25b is pivotally attached to the mounting base 22b and the other end is pivotally attached to the moving body 26. Then, the moving body 26
Drive means movably supported on the outer wall of the housing 14 and fixed to the outer wall of the housing 14,
For example, it is connected to the hydraulic cylinder 27. The one end shaft attachment portion and the other end shaft attachment portion of the link member 25 (25a, 25b) are made horizontal when the mold device is lowered.

Further, on the upper part of the die 21, there is provided a pinch 32 for sandwiching the resin extruded from the die 2a of the extruder 2 and cut by a cutting means (not shown). This pinch 3
2 is supported by a support base 33 fixed to the base 23.

A blow molding machine having such a structure is
As shown in FIG. 1, in the “extrusion” step, a thermoplastic molten resin (parison) is extruded into the open mold 21, and the mold 21 is closed and the mold 21 is closed in the “blowing and cooling” step. Hollow molding of bottles, etc. that are molded by supplying air to the inside and cooling the bottle via a mold (air supply means and cooling means are not shown), and then opening the mold in the "take-out" step Take out the item.

Next, the operation of the mold device when moving from the "extrusion" step to the "blowing, cooling" step will be described. Due to the intermittent rotation of the rotary table 10, the mold device 20 sent to the "extrusion" step is in a state of being raised by the cylinder 30, and therefore the molds 21a, 2a.
1b is opened by the link members 25a and 25b. In the "extrusion" step, the thermoplastic molten resin is extruded from the die 2a of the extruder 2 between the molds 21a and 21b in the open state. When a predetermined amount of thermoplastic molten resin is extruded, the molten resin is cut by cutting means (not shown).

At the same time as cutting, the pinch 32 holds the resin, and then the cylinder 30 lowers the base 23.
As the mold 21 descends, the link members 25a, 25
By the action of b, the molds 21a and 21b move in the closing direction via the mounting bases 22a and 22b. That is, the mold 21 is clamped simultaneously with the lowering of the base 23 only by the lowering operation of the base 23 by the cylinder 30, whereby the mold is clamped in a state where the molten resin is not accumulated on the upper part, and the next "blow" is performed. , Cooling ”process.

In the case of this embodiment, the die is clamped in a two-step motion. The first step is performed by moving the molds 21a and 21b as the mold 21 descends. At this time, the mold 21b is left with a slight movement allowance s. Then, in the second stage mold clamping, the hydraulic cylinder 27 moves the mold 21b by the moving allowance s,
This is performed by further moving (see FIG. 3). Molding can be sufficiently performed by clamping the mold by a one-step motion, but in order to facilitate adjustment of the manufacturing accuracy of the member, it is desirable to perform the mold clamping by a two-step motion as in this embodiment.

In the "take-out" step, the cylinder 30
"Extrusion" by raising the base 23 by
The operation opposite to the operation when moving from the process to the "blowing, cooling" process is performed, and the mold 21 is raised and the mold is opened at the same time. And the blow molded parison is a pinch 32
It is lifted up by the same amount as the mold while being held in, and delivered to a take-out device (not shown).

FIG. 4 is a front view of a vertical type rotary extrusion blow molding machine showing a second embodiment of the present invention, a part of which is omitted and a main portion has a cross section. In this vertical rotary extrusion blow molding machine, the rotary table 10 is arranged in the vertical direction and is rotated by a rotary shaft 15 which is arranged horizontally, and the mold device 20 is provided at the side edge portion of the rotary table 10 or the like. It is installed at intervals. Mold device 20
The configuration and operation of are the same as those of the first embodiment. Reference numeral 16 is a gear for transmitting power to the rotary shaft 15, and is connected to a motor or the like via a small gear (not shown).

The present invention is not limited to the above embodiments, but can be variously modified within the scope of the invention. For example, the link member 25 may be other than the horizontal link, and the hydraulic cylinder 27 may be provided on both the molds 21a and 21b.

[0020]

As described above, according to the present invention, a single drive unit is used to move the mold up and down and to open and close it, and to move only the minimum required amount up and down. Enables simplification and downsizing of extrusion blow molding machines.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of a horizontal rotary type extrusion blow molding machine.

FIG. 2 is a front view in which a part of the above embodiment is omitted and a main part is a cross section.

FIG. 3 (a) is an enlarged explanatory view of an essential part showing an embodiment of the same, and FIG. 3 (b) is a plan view of a pinch part.

FIG. 4 is a front view of a vertical type rotary extrusion blow molding machine showing a second embodiment of the present invention, a part of which is omitted and a main portion has a cross section.

FIG. 5 is a front view in which a part of a conventional rotary extrusion blow molding machine is omitted and a main part is a cross section.

[Explanation of symbols]

 2 Extruder 10 Rotary Table 14 Housing 20 Mold Device 21 (21a, 21b) Mold 22 (22a, 22b) Mounting Base 23 Base 24 Sliding Path 25 (25a, 25b) Link Member 26 Moving Body 27 Hydraulic Cylinder 30 Cylinder

Claims (4)

(57) [Claims] 1. A rotary extrusion blow wherein a plurality of molds are arranged on a rotary table for horizontal intermittent drive, thermoplastic molten resin is extruded from the extruder into the molds, and then the mold is separated from the extruder. In a molding machine, a base that supports the mold so as to be openable and closable, a drive unit that moves the base up and down, one end directly or indirectly axially attached to the rotary table, and the other end to the mold. A rotary extrusion blow molding machine, comprising: a link member that is mounted on a shaft and opens the mold when the mold rises, and closes the mold when the mold descends. 2. The rotary extrusion blow molding machine according to claim 1, wherein the mold is provided via a mounting base that moves on a base and is pivotally attached to the other end of the link member. 3. The mold can be opened and closed separately from the opening and closing by vertical movement of the base by pivotally attaching one end of the link member to a drive means directly or indirectly attached to the rotary table. The rotary extrusion blow molding machine according to claim 1 or 2. 4. A rotary extrusion blow molding machine using a hydraulic cylinder as a drive means according to claim 3.