JP2008230087A - Ejector pin and molding machine having ejector pin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ejector pin which can hold a molding released from a mold without spoiling its appearance and a molding machine. <P>SOLUTION: The ejector pin 1 for the molding machine for molding foamed resin beads has a pin body 10 for ejecting the molding by its front edge surface 20. Ventilation parts having widths or diameters smaller than the particle sizes of the foamed resin beads are formed in the front edge surface 20, communicate with through holes 31 passing through the pin body 10, and are channels 22, 23, and 24 formed in the front edge surface 20, slits 60 or holes 65 opened in a fitting member 6 fitted in the front edge surface 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an eject pin for extruding a molded product and a molding apparatus having the eject pin, and more particularly to an eject pin and a molding apparatus for extruding a foamed resin molded product.

Some molding apparatuses for molding a foam molded product are provided with a fixed die and a movable die facing each other, and move the movable die to the side to take out the molded product. 2. Description of the Related Art Conventionally, there has been proposed a molding apparatus that has been devised so as not to inadvertently drop a molded product at the time of mold release.
11 (a) and 11 (b) are cross-sectional views showing a conventional molding apparatus (7) (see Patent Document 1). This is because the foamed resin beads are filled in the cavity (50) which is the space between the fixed mold (4) and the movable mold (5). The fixed mold (4) is provided with a feeder (40) for sending foamed resin beads to the cavity (50), and an eject pin (1) for extruding the foamed resin molded product (8) in the cavity (50) after mold release. ing. The eject pin (1) fits into the guide (41) and is provided so as to be able to appear and retract with respect to the cavity (50).

Heating / cooling chambers (42), (51) are provided outside the fixed mold (4) and the movable mold (5), respectively, and heating steam is sent to the heating / cooling chambers (42), (51) to transmit the cavity (50). The foamed resin beads inside are foamed and fused, and cooling water is sent to cool the molded product after molding.
At the time of molding, as shown in FIG. 11 (a), the foamed resin beads are sent from the feeder (40) into the cavity (50) with the fixed mold (4) and the movable mold (5) being clamped. After the foamed resin beads are foamed and fused by the heating steam sent to the heating / cooling chamber (42) (51), cooling water is sent to the heating / cooling chamber (42) (51) to solidify the molded product (8). Let As shown in FIG. 11 (b), the movable mold (5) is separated from the fixed mold (4), and the molded product (8) is pushed out from the fixed mold (4) by the eject pin (1).
At this time, in order to prevent the molded product (8) from dropping from the eject pin (1), as shown in FIG. 12, a needle (15) that pierces the molded product (8) is provided at the tip of the eject pin (1). Some hold the molded product (8).
Moreover, as shown in FIG. 13, while providing the concave surface (16) in the front end surface of the eject pin (1), the through-hole (31) connected to the concave surface (16) is opened inside the eject pin (1), and it penetrates. It has also been proposed to suck and hold the molded product (8) with a suction device (not shown) connected to the hole (31).
The molded product (8) held by the needle (15) or sucked by the suction device is removed by a take-out device (not shown) that enters between the fixed die (4) and the movable die (5) after mold release. It is taken out.

JP-A-5-42610

In the eject pin (1) provided with the needle (15) shown in FIG. 12, a hole is opened on the surface of the molded product (8), and the appearance of the molded product is impaired. In particular, when moisture enters the hole, foreign matter may permeate into the molded product (8) and become dirty.
Further, as shown in FIG. 13, when the concave surface (16) is provided on the tip surface of the eject pin (1) and the molded product (8) is sucked, the foamed resin beads before completely solidified on the concave surface (16) are obtained. Intrusion and unnecessary convex surfaces may be formed on the surface of the molded product (8). That is, with the conventional eject pin (1), the appearance of the molded product (8) may be impaired.
An object of the present invention is to provide an eject pin and a molding apparatus that can hold a molded product after mold release without impairing appearance.

  An eject pin (1) for a molding apparatus for molding foamed resin beads has a pin body (10) whose tip surface (20) pushes out a molded product. A ventilation portion having a width or diameter smaller than the particle diameter of the foamed resin beads is formed on the tip surface (20), and the ventilation portion is a through hole (31) extending in the axial direction in the pin body (10). It is connected to.

1. At the time of molding, the molded product is passed through the ventilation part formed on the tip surface (20) of the pin body (10), specifically through the slit (60), hole (65) or groove (22) (23) (24). Aspirate (8). The width or diameter of the ventilation part is narrower than the particle diameter of the foamed resin beads which are the material of the molded product (8). As a result, the foamed resin beads do not enter the ventilation portion when the molded product (8) is sucked, and an unnecessary convex surface is not formed on the surface of the molded product (8), so that the appearance of the molded product (8) is not visible. Absent. Further, since the molded product (8) is sucked, it does not fall carelessly after the mold release.
2. When the molded product (8) is taken out after the mold release, the molded product (8) can be easily detached from the eject pin (1) if air is fed through the ventilation portion. Thereby, the defect that the molded product (8) is difficult to be separated from the eject pin (1) at the time of mold release can be reduced.
Furthermore, the timing of holding and taking out the molded product (8) can be arbitrarily set by the operator, so that the molding operation becomes easier.

First Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional plan view showing the molding apparatus (7) of this example. The molding apparatus (7) is similar to the conventional molding apparatus shown in FIGS. 11 (a) and 11 (b), but a supply / exhaust tube (70) is connected to the base end of the eject pin (1). is doing. The tube (70) is connected to an air supply / exhaust device (not shown).
2 is a cross-sectional plan view of the eject pin (1), FIG. 3 (a) is a left side view of the pin body (10) of FIG. 2, and FIG. 3 (b) is the tip of the pin body (10). FIG. The pin body (10) of the eject pin (1) has a shaft portion (30), a small diameter portion (3), and a large diameter portion (2) in this order along the extrusion direction of the molded product. The tip face (20) of 2) extrudes the molded product. A concave portion (21) having a circular cross section is formed in the tip surface (20) of the large diameter portion (2). The concave portion (21) is connected to a through hole (31) extending in the axial direction (longitudinal direction of the pin main body (10)) in the pin main body (10), and the tube ( 70) is connected. The fitting (6) is fitted into the recess (21) as will be described later.

The small-diameter portion (3) and the large-diameter portion (2) are circular in cross section, but the shaft portion (30) is formed in a hexagonal cross-section to prevent rotation. For example, as shown in FIG. 4, in some pin bodies (10), the tip surface (20) is inclined obliquely with respect to the extrusion direction in accordance with the shape of the molded product. When such a pin body (10) rotates about the central axis L, the direction of the tip surface (20) changes as shown by the alternate long and short dash line, and the molded product (8) cannot be accurately ejected.
Therefore, the shaft part (30) of the pin body (10) and the inner surface of the guide (41) are formed in a hexagonal cross section to prevent the pin body (10) from rotating carelessly. The fixed die (4) is exchanged according to the shape of the molded product (8), but the same guide (41) is used regardless of the shape of the molded product (8). On the other hand, the shaft portion (30) is formed in a hexagonal cross section so as to match the guide (41) even on a substantially perpendicular vertical surface.

An annular first groove (22) is formed on the periphery of the recess (21) on the tip surface (20) of the large diameter portion (2), and the inner end of the first groove (22) is a recess ( 21) A number of second grooves (23) and (23) extend radially outward from the first groove (22). Furthermore, an annular third groove (24) connecting the outer ends of the second grooves (23) and (23) is formed concentrically on the outside of the first groove (22). On the front end face (20), an annular third groove (24) is formed outside the first groove (22), and the outer end of the second groove (23) is connected to the third groove (24).
The first to third grooves (22), (23), and (24) are formed in a V-shaped cross section or a U-shaped cross section, and the cross-sectional shape and depth of each of the grooves (22), (23), and (24) are the same. Although not necessary, the width of the first to third grooves (22), (23) and (24) (t1 in FIG. 3 (b)) needs to be narrower than the diameter of the resin beads as the raw material of the molded product. is there. If the width of the first to third grooves (22), (23), and (24) is wider than the diameter of the resin beads, the resin beads at the time of foaming are the first to third grooves (22), (23) ( 24) This is to prevent them from entering and forming convex portions on the surface of the molded product. The widths of the first to third grooves (22), (23), and (24) are 0.1 to 0.8 mm, preferably 0.3 to 0.8 mm, but are not limited to this width.

FIG. 5 is a perspective view of the fitting (6) that fits into the recess (21). The fitting (6) is a metal and cylindrical general-purpose product. A plurality of slits (60) and (60) are opened at the tip, and the bottom of the hole is opened on the inside to connect to the slits (60 and 60). A recess (61) has been established (see FIG. 2). The width S of the slit (60) is narrower than the diameter of the resin beads as in the first to third grooves (22), (23), and (24), and the resin beads do not fit into the slit (60).
FIG. 6 is a right side view of the large diameter portion (2) fitted with the fitting (6). The slit (60) of the fitting (6) communicates with the first groove (22) at the periphery of the recess (21). Accordingly, air can flow from the third groove (24) to the through hole (31) through the fitting (6), and the first to third grooves (22), (23), (24) and the slit ( 60) forms a vent.
Accordingly, when air is sucked from the through hole (31) to make the concave portion (21) of the large diameter portion (2) negative pressure, the first to third grooves (22) (23) are inserted via the fitting (6). ) (24) also becomes negative pressure, and suction force acts. That is, a suction force acts on the distal end surface (20) of the large diameter portion (2) over a wide range where the first to third grooves (22), (23), and (24) are formed.
In this example, the slit (60) is opened in the fitting (6). However, as shown in FIG. 7, a plurality of holes (65) (65) may be opened instead of the slit (60). Good. In this case, the diameter t2 of the hole (65) is smaller than the diameter of the resin beads. However, since the hole (65) in FIG. 7 is not connected to the first to third grooves (22), (23), and (24), it is necessary to increase the diameter of the fitting (6) in order to increase the suction force. is there.

  FIG. 8 is an enlarged cross-sectional plan view of the large-diameter portion (2) in FIG. 6 and shows a state where the eject pin (1) is pushed out from the fixed die (4) while sucking the molded product (8). . In FIG. 8, the large-diameter portion (2) is broken along the plane including the line BB in FIG. As described above, a suction force acts over a wide range on the inner side of the tip surface (20) of the large diameter portion (2), so that the force for sucking the molded product (8) can be increased, and the pin body Even if (10) is extruded, the molded product (8) does not fall. If air is supplied from the through hole (31), the negative pressure state is released and the molded product (8) can be taken out by the take-out device.

Second Embodiment FIG. 9 is a side view showing the distal end surface (20) of another pin body (10). In this example, two fourth grooves (25) and (25) perpendicular to each other through the central axis L are opened on the tip surface (20) inside the third groove (24). (25) The tip surface (20) is divided into four surfaces by (25). A recessed portion (21) in which the fitting (6) is fitted is opened in each partitioned surface. Each recess (21) communicates with the third groove (24).
FIG. 10 is an enlarged cross-sectional view of the large-diameter portion (2) of FIG. 9 taken along the plane including the line C-C and viewed from the direction of the arrow. The through hole (31) is divided in the large diameter portion (2) and is connected to each recess (21). Also with this configuration, the molded product (8) can be sucked or taken out via the fitting (6).
It is also conceivable to directly open a slit (60) penetrating the pin body (10) along the longitudinal direction of the pin body (10). However, since the slit (60) is thin, it is actually difficult to open the slit (60) that penetrates the pin body (10) in the axial direction. Therefore, the eject pin (1) is configured as disclosed above.

Advantages of this example The eject pin (1) of this example and the molding apparatus using the eject pin (1) have the following advantages.
1. At the time of molding, the molded product (8) is passed through the ventilation part which is the slit (60), hole (65) or groove (22) (23) (24) formed in the tip surface (20) of the pin body (10). The diameter or width of the ventilation part is narrower than the particle diameter of the foamed resin beads that are the material of the molded product (8). Thereby, the foamed resin beads do not enter the slit (60), the hole (65) or the grooves (22), (23), and (24) when sucking the molded product (8), and are unnecessary on the surface of the molded product (8). Does not form a projecting surface. That is, the appearance of the molded product (8) is not impaired. Further, since the molded product (8) is sucked, it does not fall carelessly after the mold release.
2. A large number of ventilation portions are formed over the entire front end surface (20), and exert a suction force on a wide area of the front end surface (20). Thereby, the suction force of the molded product (8) is increased, and even if the molded product (8) is heavy, the molded product (8) can be held without being accidentally dropped.
Further, when the molded product (8) is taken out after the mold release, the molded product (8) can be easily detached from the eject pin (1) if air is fed into the vent through the through hole (31). Thereby, the defect that the molded product (8) is difficult to be separated from the eject pin (1) at the time of mold release can be reduced. If the molded product (8) does not move away from the eject pin (1), in the worst case, the molding device (7) may stop operating or the molded product (8) may have a defective shape. .
Furthermore, the timing of holding and taking out the molded product (8) can be set arbitrarily by the operator, facilitating the molding operation.
3. In this example, the molded product (8) can be satisfactorily held or taken out only by remodeling the eject pin (1) and setting the air supply / exhaust device, and no major remodeling of the molding device is required. Therefore, it is possible to achieve the effect of favorably holding or taking out the molded product (8) at low cost and in a short time.

  The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications can be made within the technical scope described in the claims.

It is a cross-sectional top view which shows a shaping | molding apparatus. It is a section top view of an eject pin. (a) is a left side view of the pin body of FIG. 2, and (b) is a right side view of the tip of the pin body. It is a figure which shows the pin main body in which the front end surface inclined. It is a perspective view of a fitting. It is a right view of the large diameter part which fitted the fitting. It is a side view which shows another large diameter part. It is a cross-sectional top view which expanded the large diameter part, Comprising: The state extruded from the fixed mold | type was shown, attracting | sucking a molded article. It is a side view which shows the front end surface of another pin main body. It is the expanded sectional view which fractured | ruptured the large diameter part of FIG. 9 in the surface containing CC line, and was seen by the arrow. (a), (b) is sectional drawing which shows the conventional shaping | molding apparatus. It is a front view of the conventional eject pin. It is a front view of another conventional eject pin.

Explanation of symbols

(1) Eject pin
(6) Mating element
(10) Pin body
(20) Tip surface
(31) Through hole
(60) Slit

Claims (5)

In an eject pin that is used in a molding apparatus for molding foamed resin beads, the tip surface has a pin body that extrudes a molded product, and a through hole extending in the axial direction is opened in the pin body.
An eject pin characterized in that a vent portion having a width or diameter smaller than the particle diameter of the foamed resin beads is formed on the tip surface of the pin body, and the vent portion communicates with a through hole. The eject pin according to claim 1, wherein the ventilation portion includes a slit or a groove, and the slit or the groove extends outward from a center portion of the distal end surface. 2. The eject pin according to claim 1, wherein the ventilation portion includes a slit and a groove, the slit is formed in a fitting that fits in the tip surface, the groove is formed in the tip surface, and the slit and the groove communicate with each other. The eject pin according to claim 3, wherein a plurality of fittings are fitted on the front end surface. The fixed mold and the movable mold are arranged opposite to each other so that they can approach and separate from each other, and an eject pin having a pin main body whose tip surface pushes out the molded product is provided in the fixed mold so that it can be projected and retracted. In the molding device for molding foamed resin beads connected to the air supply / exhaust device,
A molding apparatus characterized in that a ventilation portion having a width or diameter smaller than the particle diameter of the foamed resin beads is formed on the tip surface of the pin body, and the ventilation portion communicates with the through hole.

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