JP4013387B2 - Synthetic resin insert - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a composite used when forming ducts and hoses through which gas or liquid is passed by blow molding, simultaneously using insert molding, and simultaneously forming a place where a branch flow path constructing pipe is attached. The present invention relates to a resin insert.
[0002]
[Prior art]
Regarding the insert used for the above-mentioned application, JP-A-7-124999 discloses an insert having a bottomed short tube. The bottom part of this insert serves to block the blow molding resin from entering the short tubular part of the insert during blow molding, but after the blow molding, it is perforated to communicate between the inside and outside of the hollow blow molding. The The short tubular portion connected to the bottom portion of the insert protrudes to the outside of the hollow blow molded body, and the branch flow path constituting pipe is inserted and fitted inside the short tubular portion. If the insert used for such applications is made entirely of a soft material having a bending elastic modulus of 3,000 Kgf / cm ² or less, good insertability and airtightness between the insert and the branch flow path configuration pipe can be obtained. To that effect, the above-mentioned gazette describes it.
[0003]
[Problems to be solved by the invention]
According to the results of various tests using the above-mentioned insert made of a soft material having a flexural modulus, the insert and the hollow blow molded body can be satisfied even in terms of the mounting property and airtightness between the insert and the pipe for constituting the branch flow path. In view of the fixing strength and the pull-out strength after assembly, there is still room for improvement, and the present invention provides an insert in which these points are improved.
[0004]
[Means for Solving the Problems]
The synthetic resin insert according to the present invention has a bottomed short tubular shape including a short tubular portion and a bottom portion that seals one opening portion of the short tubular portion, and the short tubular portion is a blow molded article. The bottom portion is embedded in the blow molded body, and a branch flow path forming pipe is inserted and fitted inside the short tubular portion. The inner layer portion is made of a soft synthetic resin, the outer layer portion of the short tubular portion and the bottom portion integrally connected to the outer layer portion are made of a hard synthetic resin, and the short tubular portion is formed on the outer layer portion of the short tubular portion. Vertical slits for facilitating expansion / contraction by external force applied to the portion are provided at a plurality of locations.
[0005]
A concave groove may be provided on the peripheral side surface of the bottom portion having a diameter larger than that of the outer layer portion of the short tubular portion, and a ridge projecting outward may be provided on the upper end edge of the outer layer of the short tubular portion that is in contact with the longitudinal slit.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. 1A. This synthetic resin insert 1 seals the short tubular portion 2 and one opening portion of the short tubular portion 2 as in the conventional example. The bottom part 3 has a bottomed short tubular shape, and is used for insert molding at the same time as blow molding to obtain a hollow blow molded body such as a duct or a pipe. ), The bottom portion 3 is embedded in the hollow blow molded body 10, the short tubular portion 2 protrudes outward from the hollow blow molded body 10, and blow molding resin enters the short tubular portion 2 during blow molding. The bottom portion 3 of the insert 1 which has been sealed so as not to be blown is perforated after blow molding, so that the inside and outside of the hollow blow molded body 10 are communicated. In actual use, as shown in FIG. 2B, the branch channel pipe 11 is fitted and mounted inside the short tubular portion 2, and is fastened by the band 12 from the outside of the short tubular portion 2.
[0007]
One feature of the insert 1 is that the short tubular portion 2 has a two-layer structure of an inner layer portion 2a and an outer layer portion 2b. The inner layer portion 2a is made of a soft synthetic resin such as an olefin thermoplastic elastomer, and the outer layer portion. The bottom portion 3 integrally connected to 2b and the outer layer portion 2b is made of a hard synthetic resin such as polypropylene. Such a structure can be manufactured by a known two-color injection molding method. Since the outer layer portion 2b of the insert 1 and the bottom portion 3 integrally connected to the outer layer portion 2b are made of hard synthetic resin, the fixing strength of the insert 1 and the hollow blow molded body 10 and the pulling strength after assembly are as follows. On the other hand, since the inner layer portion 2a of the short tubular portion 2 into which the branch flow path constituting pipe 11 is fitted and mounted is made of a soft synthetic resin, the insert 1 and the branch flow path constituting pipe 11 can be made strong. A good mounting property and airtightness are sufficiently guaranteed. The peripheral side surface of the bottom portion 3 of the insert 1 forms a thin plate-like overhang portion 5 and a concave groove portion 6 following the thin plate-like overhang portion 5. The form of the thin plate-like overhanging portion 5 and the concave groove portion 6 can be appropriately determined from the viewpoint of being easily welded to or closely adhered to the blow molding resin and obtaining a sufficient locking effect. Further, as shown in FIG. 1B for easy understanding, the outer layer portion 2b of the short tubular portion 2 is formed with longitudinal slits 4 at a plurality of locations obtained by equally dividing the circumference of the outer layer portion 2b. If the outer layer portion 2b made of a hard synthetic resin lacking such a vertical slit 4 is difficult to expand and contract the outer layer portion 2b, it is difficult to install the branch flow path forming pipe 11, but the vertical slit 4 If provided, the pipe 11 for branch flow path configuration can be easily mounted and can be effectively tightened even if the band 12 is tightened.
[0008]
In the illustrated example, a flange 7 is formed between the vertical slits 4, 4 at the upper end edge of the outer layer portion 2 b of the short tubular portion 2. In addition to reinforcing the outer peripheral edge of the short tubular portion 2, the collar 7 serves to prevent the band 12 from falling off.
[0009]
【The invention's effect】
In the present invention, as described above, the insert bottom portion embedded in the blow molding resin and the outer layer portion of the insert short tubular portion connected to the bottom portion are made of a hard synthetic resin, and further on the peripheral side surface of the bottom portion. Combined with the provided thin plate-like projecting part and concave groove part, the fixing strength of the insert with respect to the hollow blow molded article and the pullout strength after assembly can be sufficiently increased. Since the inner layer portion of the insert short tubular portion to be fitted is made of a soft synthetic resin, the attachment property and the airtightness between the insert and the branch flow path constituting pipe can be maintained well without being impaired. Since the outer layer portion of the short tubular portion is provided with vertical slits at a plurality of locations that equally divide the circumference, it is easy to expand and contract, and when the pipe for constructing the branch flow path is inserted and assembled or tightened with a band Sometimes it can be assured. In addition, when a ridge is provided on the upper end edge of the outer layer of the short tubular portion that falls between the vertical slits, in addition to reinforcement, the band that is tightened from the outside of the short tubular portion is prevented from falling off.
[Brief description of the drawings]
FIG. 1 (A) is a partially sectional side view showing an embodiment of the present invention, and FIG. 1 (B) is a perspective view showing a state of the slit.
FIG. 2 (A) is a cross-sectional view of a blow molded product, and FIG. 2 (B) is a side view with a partial cross section showing an attached state.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Synthetic resin insert 2 Short tubular part 2a Inner layer part 2b Outer layer part 3 Bottom part 4 Vertical slit 5 Thin plate-like overhang part 6 Concave groove part 7 鍔 10 Hollow blow molding 11 Pipe 12 for branch flow path configuration Band

Claims (3)

The short tubular portion has a bottomed short tubular shape including a short tubular portion and a bottom portion that seals one opening portion of the short tubular portion, and the short tubular portion protrudes from the blow molded body, and the bottom portion is a blow molded body. A synthetic resin insert embedded in and used by inserting and fitting a pipe for constituting a branch channel inside the short tubular portion,
The inner layer part of the short tubular part is composed of a soft synthetic resin, the outer layer part of the short tubular part and the bottom part integrally connected to the outer layer part are composed of a hard synthetic resin,
A synthetic resin insert characterized in that longitudinal slits for facilitating expansion / contraction by an external force applied to the short tubular portion are formed at a plurality of locations in the outer layer portion of the short tubular portion. The synthetic resin insert according to claim 1, wherein a thin plate-like overhanging portion and a concave groove portion following the thin plate-like overhanging portion are provided on a peripheral side surface of the bottom portion. 2. The synthetic resin insert according to claim 1, wherein a flange projecting outward is provided at an upper end edge of the outer layer of the short tubular portion which is between the vertical slits.

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