JP3590599B2 - Simple blow molding machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, an apparatus for forming a thermoplastic bent pipe with a receiving port, and more particularly to a simplified blow molding apparatus for a thermoplastic bent pipe with a receiving port.
[0002]
[Prior art]
For example, the molding of sleeved thermoplastic curved tubes belongs to the secondary processing of plastics, in particular the thermal processing without elongation.
[0003]
Conventionally, such a method has been adopted in which, in order to heat and soften the outer peripheral portion of the raw material tube so as not to change the tube diameter, a core such as sand is filled and a bending force is applied to bend the material. In this case, even if a jig is used together, two or three workers are required, and both sleeves are formed after the forming process of the curved tube portion.
[0004]
In the case of such manual molding, if the diameter of the curved pipe is large, a large amount of force is required for the forced bending force, and since the heating of the material pipe is oily, there is a danger of a bad smell of oil vapor and a burn. It is a harsh working environment.
[0005]
The present applicant has proposed a molding apparatus for a thermoplastic curved pipe with a sleeve as disclosed in Japanese Patent Publication No. 4-70978, and has completely eliminated these problems to improve the work site. ing.
[0006]
That is, a splittable mold having both sleeve portions and a curved tube portion having substantially the same outer diameter as a material tube (also referred to as a PVC raw tube), and press-fitting into both ends of the material tube. In a molding apparatus for a thermoplastic curved tube with a sleeve, comprising a core mold for forming a sleeve, an end of a material pipe can be attached to one of the core molds in a retracted state of the core mold, By moving the core mold forward, the material pipe is configured to be pressed into the mold in a closed state, and a pressurized fluid having a pressure sufficient to prevent the pipe from being expanded into the material pipe is supplied to the core mold. The present invention has proposed a molding device for a thermoplastic curved tube with a sleeve, characterized in that a hole to be formed is formed and wrinkles and the like generated on the abdomen of the material tube are extended by the pressurized fluid.
[0007]
[Problems to be solved by the invention]
However, since then, in addition to the demand for the product of such a PVC sleeve double curved tube, the demand for the product of the rubber ring receiving piece curved tube by this type of molding apparatus has been increased. -It was found that there was the following problem when it was attempted to mold using a molding device for a thermoplastic curved tube with a tube.
[0008]
With the core mold for forming the sleeve in the above molding apparatus, it is difficult to form the rubber ring receiving port. Therefore, the pressure for expanding the pipe (for forming the curved pipe portion and the rubber ring receiving portion at the same time). For example, when a fluid of 10 to 12 kg / cm ² ) is used, the mold has insufficient rigidity.
[0009]
For this reason, if a mold having a rigidity to withstand such tube expansion (blow molding) is used, an excessively large device, that is, a mold for a curved pipe portion, withstands a simple wrinkle spreading pressure (for example, 2 kg / cm ² ). However, a rigid mold that can withstand tube expansion is used, and the apparatus becomes large.
[0010]
Therefore, the present inventors have conceived of applying to the molding apparatus a technique which the present applicant has already proposed (see Japanese Patent No. 3027753) and which contributes to blow molding of various PVC raw tubes. Thus, the present invention has been completed.
[0011]
That is, the present invention has a main object of solving the above-mentioned problems, and has a secondary object of molding not only a blow molding of a rubber ring receiving port but also other receiving ports (for example, a TS joining receiving port) with high precision. I do.
[0012]
[Means for Solving the Problems]
In order to achieve this object, the present invention relates to 1) a high-pressure blow molding die and a low-pressure blow molding die which are integrally connected to each other, and a single heat-softened thermoplastic is provided in these dies. An apparatus for accommodating a synthetic resin raw tube and supplying a high pressure to the high-pressure blow molding die and a low pressure to the low-pressure blow molding die to perform each blow molding, wherein the high-pressure blow molding is performed. A bag-like elastic skin is inserted into a mold, one end of the original tube is fitted to the bag-like elastic skin in a free state, and the high pressure is supplied to the bag-like elastic skin. A simple type blow molding apparatus characterized by performing blow molding; and 2) the high pressure type blow molding die is a cavity for molding a receiving portion, and the low pressure type blow molding die is a curved tube. 2. A simplified blow molding according to claim 1, wherein a curved thermoplastic synthetic resin tube with a port is molded as a cavity for molding the portion. The gist of the location.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described in more detail with reference to the embodiments shown in the accompanying drawings.
[0014]
1 is an overall schematic view of an embodiment of the present invention, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is an overall view of the rubber ring receiving piece bent tube formed in FIG. .
[0015]
The curved pipe forming apparatus 1 according to the embodiment of the present invention, which is a simple type, has a very simple structure, and has a normal PVC rubber ring port. One-sided bent pipes, of course, for example, are made of impact-resistant hard PVC for conduits with a nominal diameter of 100 mmφ to 350 mmφ (usually called Hi-PVC pipes, which can withstand 20 to 30 times the impact at normal temperature compared to ordinary pipes, It is a molding device suitable for molding a rubber ring receiving piece bending tube (with a curvature of 1.5 m to 10 m) which can withstand 4 to 6 times the impact at low temperature.
[0016]
First, a molding apparatus 1 used for blow molding of the present embodiment will be described.
[0017]
The split mold 2 of the molding apparatus 1 which is divided into upper and lower or right and left halves is simply and integrally connected to a mold 3 for a curved pipe part for low pressure and a mold 4 for a socket part for high pressure. Then, the rubber ring receiving piece bending pipe 6 shown in FIG. 3 is blow-molded.
[0018]
In the curved tube part mold 3, when the PVC raw tube 7 softened by heating (for example, 150 ° C. higher than normal 120 to 130 ° C.) is pushed into the curved tube part mold 3 by a small force, and It is curved at a predetermined curvature, and its abdomen becomes wrinkled, and its cross-sectional shape becomes a flat shape such as an ellipse.
[0019]
Therefore, the mold 3 has a rigidity enough to secure the roundness by correcting them, that is, a rigidity that can withstand a low-pressure blow molding pressure (for example, 2 kg / cm ² ) that causes a slight extension. The mold 3 for a curved tube part having the following. For example, it is composed of a simple aluminum mold.
[0020]
Accordingly, the curved tube portion mold 3 can be manufactured at a low cost. In particular, even if the curved tube having the same nominal diameter, that is, the receiving portion is the same, the curvature thereof is different from a plurality of types (for example, a back-to-back dimension of 2 m to 2 m). Even if 5 m is fixed, the curvature needs to be 1.5 m, 3.0 m, 5.0 m, and 10.0 m).
[0021]
In addition, the cavity of the receiving portion mold 4 has a rubber ring receiving portion 5 having a relatively complicated shape having a seal ring groove 8 'with a lip and a receiving stopper 9'. The length of the receiving port is short (for example, about 15 cm) and, since the mold 4 is a small chamber, the PVC pipe is kept at a predetermined (normal) blow molding pressure (for example, 10 to 12 kg / cm ² ). Although it is necessary to form the tube 7 by expansion, it has rigidity, but can be made as simple as possible because of the small chamber.
[0022]
As described above, a fluid pressure (for example, room temperature pressurized air or oil pressure) having a different blow molding pressure is applied to the curved tube mold 3 and the receiving mold 4 in order to shorten the molding cycle. Further, since the PVC pipe 7 heated and softened is supplied almost at the same time due to the formability of the PVC pipe 7, it is necessary to isolate both pressurizations.
[0023]
For this reason, the receptacle mold 4 incorporates a bag-shaped elastic skin (ie, rubber tube) 10 having a narrowed end cylinder as shown in FIG. 2 of the aforementioned Japanese Patent No. 3027753, and inside the bag, By supplying a high pressure for blow molding, both molds can be used together by isolating both pressurizations.
[0024]
In order to squeeze the tip of the bag-like elastic skin 10, a rubber tube holder 11 having a thick frustoconical shape is provided on the tip side. If the maximum diameter of the rubber tube retainer 11 is slightly smaller than the inner diameter of the formed rubber ring mouthpiece bending tube 6, it is convenient for blow molding.
[0025]
At the outer end of the curved tube part mold 3 (the counter port mold 4), an original cylinder pushing air cylinder 13 is arranged. The outer end of the mold 3 is closed by a closing plate 14.
[0026]
Therefore, a low-pressure cylinder that at least opposes the low pressure of 2 kg / cm ² is used as the original cylinder pushing air cylinder 13.
[0027]
An air cylinder 15 for pushing a rubber tube is disposed at the outer end of the mold 4 for the receiving portion (the mold 3 for the curved portion), and the bag-shaped elastic skin 10 is used for the receiving portion. It is inserted into the tube end side of the PVC raw tube 7 inserted into the mold 4 and the outer end of the mold 4 for the receiving portion is closed.
[0028]
Therefore, as the rubber tube pushing air cylinder 15, at least a high pressure cylinder against the high pressure of 12 kg / cm ² is used. Therefore, the rubber tube pushing air cylinder 15 is provided with a pair of tie rods 18 and 18 and an adjustment nut 19 which are supported by the mounting substrate 16 and sandwich the cylinder rod 17.
[0029]
The bag-shaped elastic skin 10 is attached to a substrate 22 having an air inlet 20 and an air outlet 21. The substrate 22 is attached to the tip end of the cylinder rod 17 so as to be pushed and pulled. Has become.
[0030]
In FIG. 1, reference numeral 23 denotes a flexible support rod protruding from the substrate 22 and supporting the rubber tube holder 11. Even with the support rod 23, the bag-like elastic skin 10 can be freely expanded. Does not have any trouble. On the other hand, insertion into the PVC pipe 7 is convenient. Of course, the support bar 23 may not be provided.
[0031]
Next, an example of a method for forming the rubber ring receiving piece curved tube 6 using the above-described forming apparatus 1 will be described.
[0032]
First, one heat-softened PVC raw tube 7 is accommodated in the bent tube portion mold 3 and the mouthpiece mold 4. Next, the air cylinder 13 for pushing the original tube is extended to press and contact the outer end of the original tube. Then, a bag-like elastic skin 10 is inserted and inserted into one end of the PVC raw tube 7 housed in the receptacle mold 4 by extending the air cylinder 15 for pushing the rubber tube. One end side of the PVC pipe 7 is supported in a free state by the bag-like elastic skin 10.
[0033]
After the molds 3 and 4 are squeezed, about 12 kg / cm ² of compressed air is supplied to the bag-like elastic body 10 while about ² kg / cm ² is also supplied from the original cylinder pushing air cylinder 13 side. A pressurized air of cm ² is supplied to the PVC pipe 7 and blown for about 90 seconds.
[0034]
As a result, the receiving port mold 4 can blow-mold the receiving port 5 along the cavity, and the curved pipe mold 3 can blow-mold the curved pipe section along the cavity.
[0035]
Next, after the pressurized air supplied to the bag-shaped elastic skin 10 is removed, the pressurized air on the side of the air cylinder 13 for pushing the original tube is further blown for 90 seconds.
[0036]
Next, the molds 3 and 4 are opened, and the pressurized air on the side of the original cylinder pushing air cylinder 13 is further cooled and blown for 90 seconds. The air cylinder 15 for pushing the rubber tube is contracted. Then, the rubber ring receiving piece bending tube 6 which is a molded product is taken out from both the dies 3 and 4.
[0037]
The simple blow molding apparatus of the present invention is applicable not only to the rubber ring receiving piece curved tube but also to other blow molding as well as a general receiving piece with a receiving port or both receiving pipes. be able to.
[0038]
【The invention's effect】
According to the present invention, the bag-shaped elastic skin is inserted into the high-pressure blow-molding die, and one end of the original tube is fitted outside in a free state. The low-pressure blow molding die can be simplified and inexpensive while favorably and accurately conforming.
[0039]
In particular, when forming a large-diameter curved pipe with a receiving port, even when a large number of curvatures of the curved pipe are blow-molded, a common mold for the receiving section, which has a relatively complicated structure, is used. Thus, the equipment can be made inexpensive as a whole.
[Brief description of the drawings]
FIG. 1 is an overall schematic diagram of an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion A in FIG.
FIG. 3 is an overall view with a partial cross-section omitted of a rubber ring receiving piece bent tube formed according to FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Molding apparatus, 2 ... Die, 3 ... Die for curved tube part, 4 ... Die for inlet part, 7 ... PVC original tube

Claims (2)

A high-pressure blow molding die and a low-pressure blow molding die are integrally connected to each other, and a single heat-softened thermoplastic synthetic resin tube is accommodated in these dies, and the high-pressure blow molding die is housed therein. An apparatus for supplying a high pressure to a molding die and a low pressure to a low-pressure blow molding die to perform each blow molding,
A bag-like elastic skin is inserted into the high-pressure blow molding die, and one end of the original tube is fitted to the bag-like elastic skin in a free state, so that the bag-like elastic skin is inserted into the bag-like elastic skin. molding apparatus - simplified blow, which comprises molding - blow by supplying the high pressure. 2. A thermoplastic synthetic resin bent tube with a receiving port is formed by using the high-pressure blow-forming die as a cavity for forming a receiving portion, and the low-pressure type blow-forming die as a cavity for forming a bent portion. 3. A simple blow molding apparatus according to claim 1.

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