JPH06143257A - Method and apparatus for controlling bent assembly to bent shape for preforming parison - Google Patents

Abstract

(57) [Summary] [Purpose] To stably bend a parison preforming bending assembly for a two-dimensionally or three-dimensionally bent molded article into a predetermined shape. The bending assembly includes a plurality of unit members 18, 20,
22 and a short first wire 24 and a long second wire 26 which are connected to each other and are integrally spliced. The short wire passes through the upper bending surface 19 and has one end side locked to the intermediate unit member, and the long wire passes through the lower bending surface 21 and one end side is locked to the lower unit member. Fluid pressure cylinders 10 and 1 are provided above the unit member.
Two are fixed facing each other. The other end of each wire is connected to the piston rod of the corresponding fluid pressure cylinder. The bending assembly is inserted into the parison in a state of hanging in a straight rod shape. In order to bend the bending assembly into a predetermined shape, the fluid pressure cylinder on the short wire side is pulled first with a large pulling force, and the subsequent fluid pressure cylinder is pulled with a small pulling force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending shape control method and apparatus for a bending assembly for preforming a parison. In the present specification, the bending assembly is a core used for preforming a parison into a predetermined shape that is bent in two or three dimensions in advance when molding a hollow molded product that is bent in two or three dimensions. In the shape of
A plurality of unit members are integrally spliced with a plurality of wires.

[0002]

2. Description of the Related Art As a conventional blow molding method for molding a two-dimensionally or three-dimensionally bent hollow molded article, there is one disclosed in JP-A-3-240516. In the blow molding method shown therein, a bending assembly obtained by splicing a plurality of unit members with a plurality of wires is used as a preforming core. The bending assembly has a linear rod shape that hangs when the wire is loosened, and when the wire is pulled, the bending assembly has a predetermined shape in which the axis is bent two-dimensionally or three-dimensionally. At least one is configured to have an inclined curved surface. A predetermined pulling force is applied to the wire by pulling it with a wire operating device.
In order to perform blow molding, a parison is injected between the opened molds, and the bending assembly is positioned inside the parison in the state of a linear rod that hangs down. The parison is then preformed into the desired shape by pulling on the wire to bend the bending assembly. Next, after closing the mold and supplying pressurized fluid such as air into the parison to perform the final molding, loosen the wire and return the bending assembly to the hanging rod shape, and remove it from the hollow molded product. ing. This makes it possible to mold a hollow molded product that is bent in two dimensions or three dimensions. Also,
The bending assembly can be repeatedly used as a preforming core.

[0003]

However, according to the conventional blow molding method for molding a hollow molded article which is bent into a two-dimensional or three-dimensional shape as described above, depending on the shape of the molded article, the parison may have a two-dimensional shape. Alternatively, there is a problem that it may be difficult to preform into a predetermined shape that is bent in three dimensions. For example, in order to form a two-dimensionally bent hollow molded article, a bending assembly is composed of three unit members A, B, C and two wires penetrating these, and the upper unit member A A first bent surface is formed between the unit member B and the intermediate unit member B, and a second bent surface is formed between the unit member B and the lower unit member C at a position opposite to the first bent surface.
Regarding the case where a bent surface is formed, it is necessary to pull both of the two wires in order for the bent surface to have a predetermined bent shape in close contact with the surface of the mating unit member. When the same tensile force is applied to
One of the two bending surfaces (usually the upper side) does not come into close contact with the mating surface, and the posture of the bending assembly may become unstable. This is because the distance from the bending surface of the unit member to the wire connecting portion of the wire operating device is different for each bending surface, so that even if the same force is applied to each wire, once the wire begins to bend, the above distance will change. It is considered that this is because the bending moment of the wire having a large bending surface (usually the lower side) is larger. Therefore, it is difficult to preform the parison into a predetermined shape.
The present invention aims to solve such problems.

[0004]

SUMMARY OF THE INVENTION According to the present invention, an order for pulling a plurality of wires is set according to an arrangement relationship of a plurality of bending surfaces of a bending assembly, and a pulling force applied to the wires corresponding to this order is set. The above problem is solved by setting the magnitude of the pulling force so that the magnitude of is gradually reduced. That is, the bending shape control method of the bending assembly for preforming of the parison of the present invention is to insert a bending assembly in which a plurality of unit members are spliced by a plurality of wires into a parison as a straight rod by loosening all the wires. In the method of preforming the parison into a predetermined shape by bending the bending assembly in two dimensions or three dimensions corresponding to the bending surface formed on the unit member by pulling the wire, the bending assembly is formed into a linear rod shape. In this state, the wire connected to the upper unit member starts the wire pulling process earlier, and the subsequent wire pulling process operates with a smaller wire pulling force. Are trying to control. An apparatus for carrying out the above method is an apparatus for preforming a parison into a predetermined shape bent in two dimensions or three dimensions,
A bending assembly in which a plurality of unit members (18, 20, 22) are spliced together by a plurality of wires (24, 26);
A plurality of wire operating devices (10, 12, 32) that can be driven in the pulling direction and the loosening direction of the wires, respectively.
By loosening all the wires, the bending assembly is inserted into the parison as a straight rod, and by pulling the wires, the bending assembly is two-dimensional corresponding to the bending surface formed on the unit member. Alternatively, the controller (30) is intended for a device for preforming a parison into a predetermined shape by bending it in three dimensions and instructing the driving sequence of the wire operating device (10, 12, 32) and the magnitude of the pulling force. The controller (30) has a unit member (1) above the bending assembly formed into the straight rod shape in the wire operating device.
Wire manipulation device (1) for the wire (24) connected to (8)
0) Output the signal to drive first, and
The subsequent wire manipulating device (12) is supposed to output a signal so as to drive with a smaller wire pulling force. The reference numerals in parentheses indicate the corresponding members of the embodiment.

[0005]

The wire connected to the unit member on the upper end side of the bending assembly drooping in a rod shape is pulled earlier by a predetermined tensile force to bring the bent surface on the upper end side into close contact, and then downward toward the upper end side. The wire connected to the unit member close to the unit member is pulled by a gradually decreasing tensile force so that the bent surfaces are brought into close contact with each other. Thereby, all the bent surfaces can be surely brought into close contact with each other, and the bent assembly can be stably bent into a constant bent shape.

[0006]

FIG. 1 shows an embodiment of a bending assembly and a wire operating device. The bending assembly includes a first unit member 18, a second unit member 20, and a third unit member which are arranged in order from the top to the bottom in the drawing.
The unit member 22 and the first wire 24 and the second wire 26 inserted through these unit members are configured. A first curved surface 19 is formed on the lower surface of the first unit member 18, and a second curved surface 21 is formed on the lower surface of the second unit member 20.
Are formed. In the state where the unit members are arranged in the shape of a straight rod as shown by the solid line in the figure, the first bending surface 19 is formed so that the clearance to the second unit member 20 increases toward the left side in the figure, The second bent surface 21 is
It is formed so that the clearance to the third unit member 22 increases toward the right side in the drawing. The first unit member 18 and the second unit member 20 are formed with holes through which the first wire 24 can be inserted, and similarly, the first unit member 18, the second unit member 20, and the third unit member 22 are formed. , The second wire 26
There is formed a hole that can be inserted. A plane passing through the two wire axes includes the axis 23 of the unit member. That is, the two wires 24 and 26 are arranged such that one pulling force affects the other pulling force. First
A first fluid pressure cylinder (wire operating device) 10 and a second fluid pressure cylinder (wire operating device) 12 are arranged and fixed facing each other above the unit member 18 in the figure. First fluid pressure cylinder 10 and second fluid pressure cylinder 1
The guide rollers 14 and 16 are provided at the front positions of
Are arranged. The upper end of the first wire 24 in the figure is connected to the wire connecting portion 10 a of the piston rod of the first fluid pressure cylinder 10. The first wire 24 is wound around the guide roller 14, and the first unit member 1
8 and the respective holes of the second unit member 20 are inserted. The lower end of the first wire 24 in the figure is locked to the second unit member 20. Similarly, the upper end of the second wire 26 in the figure is connected to the wire connecting portion 12 a of the piston rod of the second fluid pressure cylinder 12. Second wire 26
Is wound around the guide roller 16 and inserted through the respective holes of the first unit member 18, the second unit member 20, and the third unit member 22. The lower end of the second wire 26 in the figure is locked to the third unit member 22. That is,
The first wire 24 has a shorter wire length than the second wire 26. The upper surface of the first unit member 18 in the drawing is restricted from moving upward in the drawing by a movement restricting member 28 provided in the blow molding machine. First in FIG.
The fluid pressure cylinder 10, the second fluid pressure cylinder 12, and the fluid pressure supply device 32 constitute a wire operating device. The controller 30 can output a pressure setting signal and a supply port selection signal to the fluid pressure supply device 32. The fluid pressure supply device 32 can change the magnitude of the fluid pressure according to the pressure setting signal from the controller 30.
It is possible to supply the fluid pressure to the selected supply port according to the supply port selection signal from. As a result, the first fluid pressure cylinder 10 brings the first wire 24 into one of the pulled state and the loosened state, and similarly, the second fluid pressure cylinder 12 brings the second wire 26 into the pulled state and the loosened state. It can be set to either state. That is, the piston rod of the first fluid pressure cylinder 10 can be driven in the shortening direction (the pulling direction of the wire 24) by supplying the fluid pressure to the line indicated by the solid line in FIG. 2, and the line indicated by the alternate long and short dash line in FIG. It is possible to drive the piston rod of the first fluid pressure cylinder 10 in the extension direction (the loosening direction of the wire 24) by supplying the fluid pressure to the. Further, by supplying the fluid pressure to the line shown by the broken line in FIG. 2, the piston rod of the second fluid pressure cylinder 12 can be driven in the shortening direction (the pulling direction of the wire 26), and is shown by the chain double-dashed line in FIG. By supplying the fluid pressure to the line, the piston rod of the second fluid pressure cylinder 12 can be driven in the extending direction (the loosening direction of the wire 26).
In the case of this embodiment, the fluid pressure supplied to the solid line in FIG. 2 is set to be higher than the fluid pressure supplied to the broken line in the figure. The bending assembly shown by the solid line in FIG. 1 is placed on the fixed portion, and the first wire 24
Both the second wire 26 and the second wire 26 are shown in a state where they are loosened to the extent that there is no slack (the bending assembly is in the form of a straight rod).

Next, the operation of this embodiment will be described. Figure 1
As shown by the solid line, in order to bend the bending assembly that hangs down in the shape of a straight rod into a predetermined shape, the fluid pressure supply device 32 is based on the pressure setting signal and the supply port selection signal from the controller 30.
2 to supply a fluid pressure of a predetermined pressure to the solid line in FIG. As a result, the first wire 24 is pulled by the first fluid pressure cylinder 10 with a predetermined pulling force to be in a tensioned state, and the upper surface of the second unit member 20 is the first unit member 20 as shown by a phantom line in FIG. It is positioned so as to be in close contact with the first curved surface 19 of 18. Next, in response to the command signal from the controller 30, the fluid pressure (smaller than the fluid pressure of the solid line) is supplied to the broken line in FIG. 2 while maintaining the tension state of the first wire 24. As a result, the second fluid pressure cylinder 12 pulls the second wire 26 with a pulling force smaller than a predetermined pulling force to bring the second wire 26 into a pulling state, and the third unit member 22 has an upper surface as shown by a phantom line in FIG. Is positioned so as to be in close contact with the second bent surface 21 of the second unit member 20. By doing so, both the second unit member 20 and the third unit member 22 can be positioned at the predetermined arrangement positions shown by the phantom line in FIG. As an actual work, the bending assembly is placed in a parison (not shown) with the straight rod shape shown by the solid line in FIG. It can be preformed into a dimensionally curved shape.

In the description of the above embodiment, the bending assembly is composed of three unit members 18, 20, and 22, and the wires for operating these are the first wire 24 and the second wire 26. However, the number of unit members may be two or more, and the number of wires and fluid pressure cylinders may correspond to the number of bent surfaces. Accordingly, when there are many bending surfaces, the wire pulling order may be set so that the shortest wire is pulled first, and the pulling force is set so that the longer wire has the smaller pulling force. You can do it. In the above description of the embodiment, the wire is pulled by the fluid pressure cylinder, but a rotary fluid pressure actuator may be used as the wire operation device, or an electric motor may be used.

[0009]

As described above, according to the present invention, a bending assembly for preforming a parison into a two-dimensionally or three-dimensionally bent shape can be stably bent into a predetermined shape.

[Brief description of drawings]

FIG. 1 is a view showing a bending assembly together with a wire operating device and the like.

FIG. 2 is a view showing a wire operating device.

[Explanation of symbols]

 10 1st fluid pressure cylinder (wire operation device) 12 2nd fluid pressure cylinder (wire operation device) 18 1st unit member 19 1st bending surface 20 2nd unit member 21 2nd bending surface 22 3rd unit member 24 1st Wire 26 Second wire 30 Controller 32 Fluid pressure supply device (wire operation device)

Claims (2)

[Claims] 1. A bending assembly in which a plurality of unit members are spliced with a plurality of wires is inserted into a parison as a linear rod by loosening all the wires, and the bending assembly is formed in the unit member by pulling the wires. In a method of controlling a bending shape of a bending assembly for preforming a parison for bending a two-dimensionally or three-dimensionally corresponding to a curved surface to pre-form a parison into a predetermined shape, the bending assembly has a linear rod shape. Control the wire pulling order and the magnitude of the wire pulling force so that the wire connected to the upper unit member starts the wire pulling process earlier and operates with the wire pulling force that is smaller in the subsequent wire pulling process. A method for controlling the bending shape of a bending assembly for preforming a parison, comprising: 2. An apparatus for preforming a parison into a predetermined shape bent in two dimensions or three dimensions, comprising a plurality of unit members (18, 20, 22) and a plurality of wires (24, 2).
6) having a bending assembly spliced together according to 6) and a plurality of wire manipulating devices (10, 12, 32) that can be driven in the pulling direction and the loosening direction of the wires, respectively, and loosening all the wires. Insert the bending assembly into a parison as a straight rod and pull the wire to bend the bending assembly two-dimensionally or three-dimensionally corresponding to the bending surface formed on the unit member to preform the parison into a predetermined shape. A bending shape control device for a bending assembly for preforming of a parison having a controller (30) for instructing the driving sequence of the wire operating device (10, 12, 32) and the magnitude of the pulling force. The controller (30) operates the wire (24) connected to the unit member (18) above the straight rod-shaped bending assembly of the wire operating device. For the parison preforming, characterized in that the device (10) outputs a signal to drive first and the subsequent wire manipulation device (12) outputs a signal to drive with a small wire pulling force. Bending shape control device for bending assembly.