JP4448345B2 - Mold for molding and manufacturing method of synthetic resin product using the same - Google Patents

Description

The present invention relates to a manufacturing method of a synthetic resin product using a mold and it used for molding of synthetic resin article having an internal thread portion.

  When a synthetic resin product having a shape (female screw portion) with a thread portion formed inside is obtained by injection molding, such as a synthetic resin cap, in order to demold the molded product, Since it is necessary to disengage the internal thread part of the mold from the molded part, after removing the outer mold, it is necessary to devise such as rotating the inner mold to disengage the molded product. is there.

For example, a cap made of synthetic resin is provided on the movable side with a mold that can be divided, and a rotatable mold that forms a molding space with this mold is provided on the fixed side, and it appears and disappears in this molding space. A mold in which a possible pressing body is attached so as to penetrate the center has been proposed (see Patent Document 1).
JP-A-10-16017

  However, it takes time and labor to rotate the mold one by one and disengage it from the molded product, and there is a problem that work efficiency is poor. Also, if the molded product has a large diameter or a large number of threads, the meshing area between the mold and the molded product will increase, making it difficult for them to be separated. If they are separated forcibly, the threads may be distorted or damaged. There is also a problem.

The present invention has been made in view of such circumstances, and a molding die that can be easily demolded in one operation and has a beautiful finish, and a synthetic resin product using the same. to provide a manufacturing method and an object of the present invention.

In order to achieve the above object, the present invention is a mold used for injection molding of a synthetic resin product having a female screw part, and a base plate having a stepped hole for attaching the first mold A , root source unit is disposed at a position facing the first mold a female screw shaped portion at the distal end attached to the base plate is formed, the distal end portion of the first mold a, advancing during the injection molding And forming a molding space with the first mold A, and a second mold B set so as to be retracted in a state where the molded product is held after the injection molding. The mold A is a base formed in a tapered shape in which the base portion engages with the stepped portion of the hole of the base plate and is rotatably attached in the circumferential direction, and both side surfaces extending toward the tip end approach each other toward the tip end. and parts, gear teeth formed in the root portion the outer periphery of the base portion , And a pair of two partial installment forms part female screw shaped portion at the distal end portion respectively attached forward and backward freely along the both sides are formed of the base portion, divided installment form part of the two pair of Simultaneously with the retraction of the second mold B, the two molds B move forward along the tapered side surfaces of the base part and come close to each other, so that the female screw shaping part and the molded product female screw part are disengaged. with the circumferential direction of the alignment of the female screw shaped portion in the first mold a is the base portion is rotated from the base plate rear side in the circumferential direction, the gear teeth of root portion the outer periphery of the base portion, the base plate The first gist is a molding die that is configured by meshing the meshing means provided on the side at an appropriate position.

Further, the present invention is an engagement claw in which the engagement means provided on the base plate side is detachable among the molding dies, and is exposed from the hole of the base plate of the first mold A. The screw rod is inserted into the screw hole formed on the end surface of the base portion of the base portion to be rotated, the base portion is rotated in the circumferential direction, and the gear teeth on the outer periphery of the base portion of the base portion are engaged with the meshing means at an appropriate position. Accordingly, the molding die that can adjust the circumferential position of the female thread shaping portion in the first die A is a second gist, and the meshing means provided on the base plate side includes: The gear meshes with the gear teeth on the outer periphery of the base portion of the base portion . The gear is rotated, the base portion is rotated in the circumferential direction, and the gear is stopped at an appropriate position. In mold A The molding die positioning in the circumferential direction of the female screw shaped portion is to be carried out to the third aspect.

Furthermore, the present invention uses the molding die is the first to third one aspect of shall be the fourth aspect the method of the synthetic resin products molded synthetic resin product having a female thread portion .

  That is, according to the molding die of the present invention, the first mold A for shaping the female screw portion includes a base portion, and a divided shaping portion that advances and retreats along the tapered side surfaces of the base portion. Therefore, it is possible to easily remove the molded product and remove the molded product by simply moving the divided shaped portion forward, and the work efficiency is high. In addition, an unreasonable burden is not applied to the female thread portion of the molded product, and a beautiful finish is obtained.

Moreover, mold of the present invention, the position of the female screw shaped portion in the first mold A is, since that is adjustable from the base plate rear side, the position of the thread-starting of the internal thread portion to the outer shape In the case of adjustment, it is not necessary to open the entire mold again after forming the prototype and adjust the position of the female thread shaping portion, so that the workability is further improved.

  And according to the manufacturing method of the present invention using the molding die, a synthetic resin product can be obtained very efficiently due to the structural features of the molding die.

Further, synthetic resin products that obtained by the above process is finished in beautiful internal thread portion, the screw is taken if nicely, is an excellent product.

  Next, the best mode for carrying out the present invention will be described.

  FIG. 1 is a partial cross-sectional explanatory view showing the best mode of the molding die of the present invention. This molding die is used to mold the lid 1 of a short rectangular parallelepiped cosmetic container shown in FIG. 5 by injection molding.

  As for the said cover part 1, the upper surface 2 is square shape, and the square cylinder-shaped side part 3 is extended in the downward direction from the peripheral part. Further, an internal thread portion 6 for mating with the external thread portion 5 formed in the opening of the container body 4 is extended inside the side surface portion 3.

  The molding die used for molding the lid 1 (returning to FIG. 1) is a position facing the base plate 10, the first mold A attached to the base plate 10, and the tip of the first mold A. And a second mold B that moves forward during injection molding and forms a molding space P in the shape of the target lid 1 with the first mold A. . These molds A and B are fitted and held inside the four guide plates 11 to 14. Reference numerals 15, 16, and 17 denote fastening plates. Reference numeral 18 denotes a supply plate for supplying a synthetic resin material injected from an injection machine (not shown) to the liner 19 in the mold A.

  As said 1st metal mold | die A, the type | mold for shaping the internal thread part 6 of the cover body 1 (refer FIG. 5) first has the base part 20 and two pairs of division | segmentation shaping parts 21 and 22. It is provided in combination.

  The base portion 20 has a base portion 23 which is a flange portion that engages with a step portion of the hole 30 of the base plate 10, and both side surfaces extending toward the distal end side of the body portion 24 approach each other toward the distal end portion. It is formed in a tapered shape. In addition, an inner cylinder 25 in which a part of the liner 19 is formed is fitted therein.

  On the other hand, the divided shaping portions 21 and 22 are in contact with both tapered side surfaces of the base portion 20, and the base portion 20 is provided by guide pins 26 (see FIG. 3) provided at the connecting portion with the base portion 20. It advances and retreats along both tapered side surfaces. As shown in FIG. 2, the shape combined with the base portion 20 is a substantially truncated cone shape, and a female screw shaping portion 31 is provided at a tip portion of each of the divided shaping portions 21, 22. It is formed one by one.

  Therefore, when the divided shaping portions 21 and 22 advance toward the distal end side together with the guide plates 11 and 12 that hold the divided shaping portions 21 and 22, both project toward the distal end side while approaching each other (see FIG. 3). ).

  Further, the base portion 23 of the base portion 20 is engaged with the step portion of the hole 30 of the base plate 10 and is held rotatably in the circumferential direction. And the gear tooth 32 is formed in the outer periphery of the said base part 23 in the substantially one-third part of a perimeter, and as shown in FIG. 4, the back surface side (molding is performed). On the opposite side to the side), an engaging claw 33 that partially meshes with the gear teeth 32 is provided detachably on the opening edge of the hole 30 by screwing. Therefore, the engagement claw 33 is removed as indicated by a chain line, and the gear teeth 32 of the root portion 23 are moved in the circumferential direction, thereby forming the female thread portion formed at the distal ends of the divided shaping portions 21 and 22. The position in the circumferential direction of the forming portion can be adjusted as appropriate. The gear tooth 32 can be easily moved by inserting an appropriate screw rod into the screw hole 40 formed in the root portion 23 and moving it as shown by an arrow.

  Further, as the first mold A (returning to FIG. 1), a portion between the female screw portion 6 and the side surface portion 3 of the lid body 1 (see FIG. 5) is provided around the split shaping portions 21 and 22. A partial mold 35 for shaping is provided.

  On the other hand, a second mold B for forming a molding space P between the first mold A and the first mold A is disposed at a position facing the tip of the first mold A. As said 2nd metal mold | die B, the partial type | mold 36 for shaping the outer peripheral surface of the side part 3 of the cover body 1 and the partial type | mold 37 for shaping the upper surface 2 of the cover body 1 are provided. ing.

  These molds 36 and 37 advance and retreat together with the guide plates 13 and 14 that hold them. During molding, the molds 36 and 37 advance toward the first mold A to form a molding space P. After molding, Is designed to be largely retracted so that the molded product can be removed.

  Therefore, according to the above molding die, as shown in FIG. 1, the plates 10 to 18 are usually clamped in a state where the first die A and the second die B are held inside. The molding can be performed in the molding space P in the same manner as the injection molding. Then, after cooling, the plates 10 to 18 are released from being clamped, and as shown in FIG. 3, the second mold B is moved backward together with the guide plates 13 and 14 in the right direction of the drawing, The split shaping portions 21 and 22 of the mold A are advanced together with the guide plates 11 and 12 in the right direction so that the female screw shaping portion 31 is removed from the molded product Q. Then, the molded product Q can be easily obtained by removing the molded product Q from the partial mold 36.

  The molded product Q (= lid 1) thus obtained has a beautiful finish because its female threaded portion 6 is not forcibly removed due to rotation of the mold or the like. Fits closely with part 5 (see FIG. 5).

  In addition, according to the above molding die, the circumferential position of the female screw shaping portion 31 in the first die A can be adjusted from the back surface of the base plate 10, so that the outer shape can be obtained by trial molding. In this example, it was necessary to open all the molds and readjust, when it was found that the position of the screw and the position of the screw shifted, and it was not possible to achieve a proper positional relationship. By simply removing the fastening plate 17 and the supply plate 18 on the back surface side, there is an advantage that the adjustment can be easily performed and the working efficiency is greatly improved.

  In the above example, the taper angle (indicated by θ in FIG. 1) on both sides of the taper provided on the base portion 20 of the first mold A is the shape of the molded product Q, the space when the mold is opened and closed, etc. In consideration of the above, the angle is set so that the divided shaped portions 21 and 22 can be brought close to each other so that the engagement between the female thread shaping portion 31 and the female screw portion 6 of the molded product Q is sufficiently disengaged. Incidentally, in this example, θ = 7 °.

  And in the above example, the positioning adjustment in the circumferential direction of the female screw shaping portion 31 can be performed from the back side of the base plate 10, and for that purpose, the gear teeth 32 are formed on the root portion 23 of the base portion 20, Although the engaging claw 33 is detachably provided on the base plate 10 side, the adjusting means is not limited to this configuration, and any appropriate means can be used. For example, a gear that meshes with the gear teeth 32 may be provided, and the gear may be adjusted by rotating it with a thumbscrew or the like.

In the above example, since the molded product Q is the lid 1 of the container whose outer shape is a rectangular parallelepiped, it is particularly important to appropriately determine the screw start position . That is, depending on the position of the thread-starting, because the corner portion of the corner portion and the container body 4 lid 1 is shifted.

  As described above, the present invention is not limited to the shape of the lid 1 in FIG. 5 but can be applied to the manufacture of various injection molded products having an internal thread portion.

It is a fragmentary sectional view of one Example of this invention. It is partial explanatory drawing of the 1st metal mold | die A used for the said Example. It is explanatory drawing of the usage condition of the said Example. It is partial explanatory drawing of the 1st metal mold | die A used for the said Example. It is explanatory drawing of the product obtained by the said Example.

Explanation of symbols

20 Base part 21, 22 Split shaping part 23 Root part 31 Female thread shaping part

Claims (4)

A mold used for injection molding of plastic products with an internal thread portion, and a base plate having a stepped mounting portion hole for attaching the first mold A, to the tip root source unit is attached to the base plate Between the first mold A in which the female screw shaping portion is formed and the first mold A, which is disposed at a position facing the tip portion of the first mold A and advances during the injection molding. Forming a molding space, and a second mold B set so as to retreat in a state where the molded product is held after the injection molding, and the first mold A has a root portion of the hole of the base plate. Formed on the outer periphery of the base portion of the base portion that is formed in a tapered shape that engages with the stepped portion and is attached so as to be pivotable in the circumferential direction and that is closer to each other toward the tip portion. and the gear tooth to be, it along both sides of the base portion It has two pairs of divided shaping parts that are attached so as to be able to advance and retreat and have a female thread shaping part formed at the tip, and these two pairs of divided shaping parts are used to retract the second mold B. At the same time, it advances along the tapered side surfaces of the base portion and approaches each other so that the female screw shaping portion and the molded product female screw portion are disengaged, and the female screw in the first mold A is also provided. positioning in the circumferential direction of the shaping unit, the base unit is rotated from the base plate rear side in the circumferential direction, the gear teeth of the root portion the outer periphery of the base portion, suitably of the engagement means provided on the base plate side A mold for molding, characterized in that it is performed by meshing at a position. The engaging means provided on the base plate side is a detachable engaging claw, and a screw rod is inserted into a screw hole formed in the base end face of the base part exposed from the hole of the base plate of the first mold A. By inserting and rotating the base portion in the circumferential direction, and meshing the gear teeth on the outer periphery of the base portion of the base portion with the meshing means at an appropriate position, the circumference of the female screw shaping portion in the first mold A is obtained. The molding die according to claim 1, wherein the direction position can be adjusted. The meshing means provided on the base plate side is a gear that meshes with the gear teeth on the outer periphery of the base portion of the base portion , and rotates the base portion in the circumferential direction by applying rotation to the gear. The molding die according to claim 1, wherein the position of the female screw shaping portion in the first die A in the circumferential direction is adjusted by stopping the gear.   A method for producing a synthetic resin product, comprising: molding a synthetic resin product having a female screw portion using the molding die according to any one of claims 1 to 3.