JPH0452037Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a blow molding die used for molding a blow molded product of synthetic resin.

(Prior art) As shown in FIG. 4, a parison 1 obtained by preforming a thermoplastic synthetic resin into a cylindrical shape is pressed between a pair of molds 2 and 3, and the parison 1
In recent years, a method of manufacturing blow-molded products by cooling and solidifying while pumping air into the mold has come into widespread use.

In such blow molding, the moldability during blow molding is improved by compressing the part 1a of the parison 1 between the mating surfaces of both molds 2 and 3, as shown in FIG. Attempts have been made in the past. In this case, since a portion 1a of the parison 1 remains as a burr in the blow-molded product, it is necessary to cut the burr 1a. Therefore, in the conventional method, a pair of blade parts 4 facing the mating surfaces of the molds 2 and 3,
5 is integrally formed, and the burr portion 1a is cut using the clamping force of the molds 2 and 3 (see, for example, Publication No. 111833/1983).

(Problem to be solved by the invention) As in the above-mentioned known example, a pair of cutting blades 4 and 5 facing each other are integrally formed on the mating surfaces of the molds 2 and 3, and the clamping force of the molds 2 and 3 is utilized. If the burr portion 1a is cut by using the burr portion 1a, a mold clamping force greater than the normal mold clamping force is required to cut the burr portion 1a, and increasing the mold clamping force will inevitably cause The strength of the blade portions 4 and 5 must also be increased, resulting in problems such as an increase in the size of the mold clamping means for clamping the mold or an increase in the cost of the mold itself. In addition, in the case of the method of the above-mentioned known example, the ease of cutting the burr portion 1a may vary depending on the angle of the mold mating surface with respect to the mold clamping direction, so the reliability of cutting the burr portion is low. There is a possibility that this may occur.

This invention was made in view of the above points,
The object of this invention is to ensure that the burr can be cut even with a small mold clamping force.

(Means for Solving the Problems) In the present invention, as a means for solving the above problems, in a blow molding mold consisting of a pair of molds that pinch the stretched parison from both sides,
A movable core is provided on the mating surface of one of the molds, and is equipped with a movable cutting blade for cutting the burr part of the parison, and moves in the direction of cutting the parison burr part when both molds are clamped. A fixed cutting blade configured to cooperate with the movable cutting blade to cut the parison burr portion and a guide means for guiding movement of the movable core are provided on the mating surface.

(Function) In the present invention, the following effects can be obtained by the above means.

That is, when a parison is compressed by a pair of molds, a movable cutting blade of a movable core provided in one mold moves in a direction to cut the parison burr part as the molds are clamped, and a movable cutting blade of a movable core provided in one mold, and a movable cutting edge of a movable core provided in the other mold Since the burr portion of the parison is cut by the provided fixed cutting blade, the burr portion can be reliably cut without increasing the clamping force.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

The blow molding mold of this embodiment is similar to the one shown in FIG. 4 described in the prior art section, and consists of a pair of molds that clamp a parison 1 obtained by preforming a thermoplastic synthetic resin into a cylindrical shape. Molds 2 and 3
and a nozzle 6 for force-feeding air into the parison 1 which is squeezed by the molds 2 and 3. A blow-molded product is formed by cooling and solidifying air while pumping air through the nozzle 6 into the mold. When the parison 1 is compressed by both molds 2 and 3, as shown in FIG. , burrs) are to be compressed.

In this embodiment, as shown in FIG. A movable core 7 that moves in the direction of cutting the burr portion 1a of the parison 1 (i.e., in the direction of the outer circumference of the mold 2) when both the molds 2 and 3 are clamped is provided so as to be movable back and forth. The moving core 7
is installed in a recess 2a formed in the mating surface of the mold 2 so as to be able to move forward and backward, and is guided by a guide piece 9 protruding from the mold 2 so as to be movable.
Further, the inner end surface of the movable cutting blade 8 is an inclined surface 8a having a predetermined angle. Furthermore, this moving core 7
A guide groove 11 having an opening on the open end side of the mold 2 and having the same inclination angle as the inclined surface 8 a of the movable cutting blade 8 is formed in the guide groove 11 .

On the other hand, the other mold (in the case of this example, the left mold) 3
A fixed cutting blade 10 configured to cut the burr portion 1a of the parison 1 in cooperation with the movable cutting blade 8 is integrally formed on the mating surface. The fixed cutting blade 10
The outer end surface is an inclined surface 10a having the same inclination angle as the inclined surface 8a of the movable cutting blade 8. Further, a guide pin 12 is integrally provided on the mating surface of the mold 3 and is fitted into the guide groove 11 of the movable core 7 when the molds 2 and 3 are clamped. The guide pin 12 has the same inclination angle as the guide groove 11, and the movable core 7 is moved into the parison 1 by fitting the guide pin 12 into the guide groove 11 when the molds 2 and 3 are clamped. It acts to move the burr portion 1a in the direction of cutting (that is, toward the outer circumference of the mold 2). That is, in this embodiment, the guide groove 11 and the guide pin 12 are
It is supposed to constitute a guide means 13 for guiding the movement of the moving core 7. Furthermore, when the molds 2 and 3 are opened, the moving core 7 moves as the guide pin 12 separates from the guide groove 11.
It is now possible to return to the original state.
In addition, when forming the inclined surface 8a of the movable cutting blade 8 and the inclined surface 10a of the fixed cutting blade 10 to have the same inclination angle as in this embodiment, the molds 2, 3
The movable core 7 can be moved in the direction of cutting the burr portion 1a of the parison 1 (i.e., in the direction of the outer circumference of the mold 2) by the sliding contact between both inclined surfaces 8a and 10a during mold clamping. Therefore, by interposing a return spring between the rear end of the movable core 7 and the mold 2 instead of the guide groove 11 and the guide pin 12, the movement of the movable core 7 is made easier on the inclined surfaces 8a and 10a. It is also possible to act as a guide means 13 for guiding.

Next, the operation of the illustrated blow molding die will be explained.

In the process of clamping the molds 2 and 3, first, a part 1a of the parison 1 (after molding, a burr part) is formed between the movable cutting blade 8 of the moving core 7 and the fixed cutting blade 10 of the mold 3. ) is squeezed (first
(see figure). At this time, the guide pin 12 of the mold 3 is in a state immediately before being inserted into the guide groove 11 of the moving core 7. Furthermore, as the mold clamping progresses, the movable core 7 is moved in the direction of cutting the burr portion 1a of the parison 1 (i.e., toward the outer circumferential direction of the mold 2) by the guide pin 12 being inserted into the guide groove 11. The burr portion 1a that was pressed between the cutting blade 8 and the fixed cutting blade 10 is cut off (see FIG. 2). That is, in this embodiment, the mold 2,
The burr portion 1a of the parison 1 is very easily cut by the movable cutting blade 8 of the movable core 7 and the fixed cutting blade 10 of the mold 3, which are moved as the mold clamping progresses in step 3. be. In this case, the mold clamping force may be of the level required for normal parison clamping, and there is no need to specifically increase the mold clamping force.

It goes without saying that the present invention is not limited to the configuration of the above-described embodiments, and that the design can be modified as appropriate without departing from the gist of the invention.

(Effects of the invention) As described above, according to the invention, in a blow molding mold consisting of a pair of molds that press a stretched parison from both sides, the mating surface of one of the molds is provided with a portion of the parison. A movable core is provided which is provided with a movable cutting blade for cutting the burr portion and moves in a direction to cut the parison burr portion when the two molds are clamped, and a movable core is provided on the mating surface of the other mold, and which cooperates with the movable cutting blade. A fixed cutting blade configured to cut the parison burr portion and a guide means for guiding the movement of the movable core are provided, and when the parison is clamped by the mold, the movable core is moved as the mold is clamped. Since the burr part of the parison is cut by the movable cutting blade and the fixed cutting blade on the other mold side, the mold clamping force is increased beyond the mold clamping force required for normal parison clamping. without any
This has the practical effect of being able to reliably cut the burr portion.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of a main part of a blow molding mold according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part showing the state of the blow molding mold shown in FIG. 1 when mold clamping is completed. 3 is a half-cut cross-sectional view of a blow molding mold according to an embodiment of the present invention, and FIG. 4 is a vertical cross-sectional view showing the state of a general blow molding mold when the mold is clamped.
FIG. 5 is a half-cut cross-sectional view of a conventional blow molding die. 1... Parison, 1a... Burr part, 2, 3...
Mold, 7...Movable core, 8...Movable cutting blade, 10...
...fixed cutting blade, 13...guiding means.

Claims (1)

[Scope of utility model registration request] It consists of a pair of molds that squeeze the stretched parison from both sides, and one mold has a movable cutting blade on the mating surface that cuts the burr part of the parison, and also has a movable cutting blade that cuts the burr part of the parison. A movable core that moves in a direction to cut the parison burr portion is provided, while a fixed cutting blade configured to cooperate with the movable cutting blade to cut the parison burr portion is provided on the mating surface of the other mold. A blow molding mold characterized by being provided with a guide means for guiding the movement of a moving core.