JP2547428B2 - Method for manufacturing connection part of branch pipe guard with different diameter pipe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a connecting portion of a branch line guard with a different diameter pipe used for protecting branch lines of utility poles and the like.

(Prior Art) Conventionally, as a manufacturing method of a so-called different diameter pipe connection type branch line guard in which a small-diameter tubular body and a large-diameter tubular body are connected by a tapered connecting portion, Method for forming a large-diameter portion by heating and expanding a portion, or molding a cap body as a connecting portion and locking and connecting small-diameter and large-diameter tubular bodies through the cap body, and a cap body A method has been used in which after forming, the respective tubular bodies are welded.

However, in the method of forming a large-diameter portion by heating and expansion, there is a problem in that strength is reduced due to the decrease in the thickness of the expanded portion, and in the connecting method using the cap body, the cap body and the tubular shape are caused by an external force or the like. There is a problem that the body and the cap are separated relatively easily and the connecting force is weak. Further, in the method of welding the molded cap body to the cylindrical body, there is a problem that the work process is complicated and the workability is poor. .

(Object of the Invention) Therefore, an object of the present invention is to solve the drawbacks of the prior art as described above, and to connect the tubular body and the connecting portion firmly so that the tubular body and the connecting portion are not easily separated from each other. It is an object of the present invention to provide a method for manufacturing a connection part of a branch line guard by a more simplified working process.

(Technical Means for Solving Problems) In order to achieve the above-mentioned object, in the present invention, the connecting portion of the different diameter pipe connection type branch line guard is manufactured as follows.

That is, it is shaped such that one end of a tubular body formed by forming an opening along a longitudinal direction in a peripheral wall is housed in a die including a fixed die, a movable die, and a core over a predetermined length, and the tubular shape is An annular cavity portion having an outer diameter larger than the outer diameter of one end of the body, and communicating with the annular cavity portion and extending along the longitudinal direction of the annular cavity portion and a circle A cavity is formed having an annular frustoconical cavity portion having a diameter that increases or decreases in comparison to the diameter of the annular cavity portion. Furthermore, the core is provided with a mounting member that fits in the opening over the entire length in the longitudinal direction thereof and that slidably positions the core with respect to the movable die. Using the mold configured as described above, one end of the tubular body is inserted by inserting one end of the tubular body into the annular space and then injecting a thermoplastic resin into the cavity. Joined together with
Further, the mounting member can form a tapered connection portion having a longitudinally extending opening communicating with the opening of the tubular body on the peripheral wall.

Further, according to one embodiment of the present invention, at least one through-hole is provided in the peripheral wall of the one end of the tubular body, and the core is inserted into the one end of the tubular body. When a reduced diameter portion having a diameter smaller than the inner diameter of the one end portion is formed and the core is inserted into one end portion of the tubular body and the tubular portion is inserted into the annular space portion, The reduced diameter portion and the annular space portion are communicated with each other through the through hole, whereby the thermoplastic resin passes through the through hole and is integrated with the connecting portion when the thermoplastic resin is injected. The pillars of
It is possible to firmly connect the cylindrical body and the connecting portion.

Further, according to another embodiment of the present invention, a concavo-convex portion is formed on the outer peripheral surface and / or the inner peripheral surface of one end of the cylindrical body inserted into the annular space portion, and the one end is formed. It is possible to increase the contact area between the portion and the connecting portion, and thereby increase the joining force between the tubular body and the connecting portion.

(Effect) With the above-described configuration, the present invention has the following effects.

a. The strength and welding reliability of the connection part can be increased.

b. It is possible to prevent a decrease in strength due to uneven thickness.

c. Processing workability in manufacturing can be improved.

d. The core can be accurately positioned with respect to the movable mold by the mounting member, and the opening that communicates with the opening of the cylindrical body can be formed at the same time at the time of molding, and after molding, when the mold is opened. It becomes easy to remove the molded product (the connecting portion integrated with the tubular body).

(Embodiment) Next, with reference to the drawings, a description will be given of a method for manufacturing a connecting portion of a branch pipe guard with different diameters which is an embodiment of the present invention.

FIG. 1 shows a spline guard with a different diameter pipe connection having a connecting portion manufactured by the manufacturing method of the present invention.

The branch guard is entirely hollow, and has a small-diameter tubular body 1, a large-diameter tubular body 3, and a connecting portion 5 that connects these tubular bodies.
It has and. The branch line guard has slits or openings 7 for accommodating the branch lines of the utility poles extending along the entire length in the longitudinal direction of the small-diameter and large-diameter cylindrical bodies 1 and 3 and the connecting portion 5.
Are formed.

The connecting portion 5 connects the small-diameter annular portion 9 joined to the small-diameter cylindrical body 1, the large-diameter annular portion 13 joined to the large-diameter cylindrical body 3, and the annular portions 9 and 13 to each other. It has a frustoconical portion, that is, a tapered portion 11. Connection part 5 and tubular body
The connection between 1 and 3 is performed by heat fusion when forming a connecting portion between these cylindrical bodies by injection molding as described below.

Next, FIG. 2 showing a state in which a branch wire connection type branch line guard is manufactured by the method of the present invention, and FIG. 3 showing a closed state of a mold used in this method in perspective view, and FIG.
The manufacturing method of the present invention will be described with reference to FIG. 4 which is a perspective view showing the opened state of the mold.

FIG. 2 is a sectional view showing the inside of the mold closed along the line II-II in FIG. 3, in which the fixed mold 21 and the movable mold 23 are shown.
The state in which the small-diameter cylindrical body 1 and the large-diameter cylindrical body 3 are inserted into the mold including the cores (FIGS. 3 and 4) and the core 25 (FIG. 4) is shown.

In the mold, a cavity 29 having a shape corresponding to the connecting portion 5 in FIG. 1 in its closed state is defined, and this cavity has a small-diameter annular cavity portion a and a large-diameter circle. It consists of an annular cavity portion c and an annular frustoconical cavity portion b between these cavity portions a, c (Fig. 2). The void portions a, b, c are respectively shaped to correspond to the small diameter annular portion 9, the tapered portion 11 and the large diameter annular portion 13 shown in FIG.

The fixed mold 21 has a sprue for injecting a thermoplastic resin.
31 (FIGS. 3 and 4) are formed and the sprue is connected to an injection molding machine (not shown) in the usual manner.

The mold used in the method of the present invention will be described with reference to FIGS. 3 and 4 in particular. As described above, the mold is composed of a fixed mold 21, a movable mold 23 and a core 25. A mounting member 27 is provided at 25 for slidably positioning the core with respect to the movable die 23.

The fixed die 21 includes a small-diameter annular portion of the connecting portion 5 shown in FIG.
9 ;, recesses a ', b', and c'corresponding to the tapered portion 11 and the large-diameter annular portion 13, respectively, are formed. Although not shown in the drawing, the movable mold 23 is also formed with recesses symmetrical to these recesses a ', b', and c '.
When it is pressed toward, that is, when the mold is clamped, it cooperates with the outer peripheral surface of the core 25 and has a small-diameter annular cavity portion a and an annular truncated cone-shaped cavity portion shown in FIG. b and a large-diameter annular void portion c are respectively defined.

As shown in FIGS. 2, 3 and 4, the diameter of the small diameter portion 33 of the core is made substantially equal to the inner diameter of the small diameter cylindrical body 1, and the diameter of the large diameter portion 35 is large. It is made equal to the inner diameter of the body 3. Reduced diameter portions 39 and 41 are formed between the small diameter portion 33 and the tapered portion 37 and between the large diameter portion 35 and the tapered portion 37, respectively, whereby a connecting portion formed by injecting a thermoplastic resin is formed. Can also extend to the inner surface of the corresponding cylindrical body for stronger bonding (see FIG. 2).

Next, a method of manufacturing the connecting portion of the branch line guard will be described with reference to FIGS.

The small-diameter cylindrical body 1 shown in FIG. 1 is inserted onto the small-diameter portion 33 of the mold core in the opened state and positioned as shown in FIG. Similarly, the large-diameter cylindrical body 3 is inserted on the large-diameter portion 35 of the core and positioned as shown in FIG. At this time,
It will be understood that the tubular bodies 1, 2 have openings 7 and therefore these openings are made with the plate-like mounting members 27 accommodated when inserted into the core of the tubular body.

Next, the mold is clamped from the open state shown in FIG. 4 to the closed state shown in FIG. The core mounting member 27 is a movable type 23
By sliding in the guide groove 43 formed in the contact member between the contact surfaces 45 and 49 of the mounting member 27 and the locking groove 47 (only one of which is shown), the core is fixed or movable. Positioned in the center of the cavity defined by.

After the mold is clamped as described above, the thermoplastic resin is injected from the sprue, whereby the connecting portion 5 conforming to the shape of the cavity is molded. At the same time, due to the heat of the injected thermoplastic resin, the inner ends of the tubular bodies 1 and 3 are connected to the connecting portion 5.
The respective different annular portions 9 and 13 are joined to each other, thereby forming an integral different diameter pipe connection type branch line guard.

In the above-mentioned example, the small-diameter and large-diameter tubular bodies were inserted into the mold to directly manufacture the different-diameter pipe connection type branch line guard, but the connecting portion was formed only on one tubular body to form the other tubular shape. The body can then be connected to the connection by any suitable means such as tacking.

Further, in the above example, the connection between the tubular body and the connection portion is performed only by heat fusion using the heat of the thermoplastic resin at the time of injection molding, but in order to further strengthen the connection force, As shown in FIG. 5, at least one through hole is provided around the end of the connecting portion of each tubular body, and a reduced diameter portion is provided closer to the connecting portion than the through hole, whereby the thermoplastic resin is injected. A column 50 can sometimes be formed that passes through the through hole.

Further, instead of forming the through-hole or in addition to the through-hole, unevenness such as an oblique groove and a cross groove is provided on the outer peripheral surface and / or the inner peripheral surface of the connecting portion side of the tubular body to connect with the tubular body. A stronger bond can be made between the parts.

[Brief description of drawings]

FIG. 1 is a perspective view showing a branch line connection type branch line guard manufactured by the method of the present invention, and FIG. 2 is a view showing a state in which a cylindrical body is provided in a mold for injection molding. A sectional view taken along the line II-II, FIG. 3 is a perspective view showing the mold in a closed state after inserting the tubular body, FIG. 4 is a perspective view showing the mold in the opened state, and FIG. The drawing is a sectional view similar to FIG. 2, showing a state of performing injection molding according to another embodiment. (Description of main symbols) 1,3: Cylindrical body, 5: Connection part, 7: Opening part, 9,13: Annular part, 11: Tapered part, 21: Fixed type, 23: Movable type, 25: Core , 29: cavity, 31: sprue, a, b, c: void part, a ', b', c ': recess.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location // B29L 23:00

Claims (3)

(57) [Claims] 1. A mold comprising a fixed mold, a movable mold, and a core, which is shaped so as to accommodate one end of a cylindrical body having a peripheral wall formed with an opening along the longitudinal direction over a predetermined length. An annular cavity portion having an outer diameter larger than the outer diameter of the one end of the tubular body, and communicating with the annular cavity portion and extending along the longitudinal direction of the annular cavity portion. And a cavity having an annular frustoconical cavity portion having a diameter that gradually increases or decreases in comparison with the diameter of the annular cavity portion, and further, in the core, the longitudinal direction thereof is formed. A mounting member that fits in the opening over the entire length and positions the core so as to be slidable with respect to the movable die, and insert one end of the tubular body into the annular space portion, Then inject the thermoplastic resin into the cavity Therefore, it is possible to form a tapered connecting portion integrally joined to one end of the tubular body and having a longitudinal wall extending in the circumferential wall by the mounting member and communicating with the opening of the tubular body. A method of manufacturing a connecting portion of a branch pipe guard with a different diameter pipe. 2. At least one through hole is provided in a peripheral wall of the one end of the tubular body, and an outer diameter is an inner diameter of the one end of the core at a position to be inserted into the one end of the tubular body. Forming a reduced diameter portion smaller than the diameter, inserting the core into one end of the tubular body, and inserting the tubular portion into the annular space portion, the reduced diameter portion through the through hole. Portion and the annular space portion communicate with each other, whereby the thermoplastic resin passes through the through-hole and forms a column integral with the connecting portion when the thermoplastic resin is injected, and the cylinder The method for manufacturing a connecting portion of a branch pipe guard of different diameters according to claim 1, wherein the connecting member and the connecting member are firmly connected to each other. 3. A concavo-convex portion is formed on an outer peripheral surface and / or an inner peripheral surface of one end portion of the cylindrical body inserted into the annular space portion, and between the one end portion and the connection portion. 3. The different diameter pipe connection type branch line guard according to claim 1 or 2, wherein a contact area between the tubular body and the connection portion is increased. Manufacturing method of the connection part.