JPH03159711A - Mold for synthetic resin product having internal screw part - Google Patents

Abstract

PURPOSE:To remove products from a mold without utilizing any caul or the like and affecting the products by holding a molding on a movable side mold in its end and dislodging it from the product in rotating the internal screw molding mandrel and thereafter by operating an ejector plate in order to make the product eject therefrom. CONSTITUTION:On a movable side mold plate 20, the mold forming core of a fixation side and coaxial mold forming core 21 are attached and at the center of the core 21, an internal screw molding mandrel 30 and an product extruding piece 22 engaged with an ejector plate 50 in its end are fitted coaxially. The internal screw molding mandrel 30 is provided with an internal screw molding part 31 in its tip end peripheral surface and supported rotatingly and movably in the axial direction by means of slide ball bearings 36 fitted in a spacer block in its intermediate part and the rear end 32 is formed so as not to pivot by means of an angular shaft or the like and further connected movably in the axial direction to the attaching box connecting hole 45 of a chain wheel 41 supported rotatably by a movable side attaching plate 29 and second receiving plate 26 via bearings 44, 44'. After molding, in interlocking with a mold opening operation, the internal screw molding mandrel 30 retreats rotatingly via the chain wheel 41 and the end surface of the product comes into close contact with the article extruding piece 22, thereby preventing the co-rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application: The present invention relates to a mold for molding synthetic resin products having an internal thread. BACKGROUND TECHNOLOGY: A threaded portion of a synthetic resin product is formed together with its base material by molding. If this threaded part is externally threaded, the product can be easily removed after molding by splitting the mold. However, if the product is used internally, it is not possible to easily take out the product. In other words, since the mold for shaping the threaded part is screwed into the product, it is necessary to remove the mold part from the product, and in order to improve workability, it is necessary to quickly remove the product. Since removal is required, the removal operation is performed at a stage when the product is not completely cooled and solidified after the molding operation. Therefore, there are many difficulties in removing the thread mold. As an example of a mold for forming a product equipped with this internal thread, there is known a mold as disclosed in Japanese Patent Publication No. 52-39067. In addition, elliptical types in which power is transmitted through a gear train to an internally threaded core are generally used, such as the one shown in Figure 6. Problem to be Solved: In the conventionally known mold for a synthetic resin molded product having an internal thread, it is difficult to inject resin into the cavity 70 of the mold, as illustrated in FIG. After molding, the movable side template 60
The core 61 forming the internal thread is moved back together to open the mold, and the core 61 is then rotated by a gear train 65 by power transmission from a separately provided drive machine (not shown), thereby molding is performed. An operation is being performed to push product B out of the cavity 71 of the movable template 60. To take out the product B molded by such an operation from the molding section, as shown in FIG. The molded product parts that were connected by the gate 67 are cut, and the movable template 60
It leaves the stationary side template 63 while being accommodated in the cavity 71.

After that, the product B molded from the movable template 60
In order to take out the core 61, since the core 61 is assembled into a movable mold (cavity) 71, the product 8 is inserted into the internally threaded part of the core 61 (i.e., the externally threaded part 62 provided in the core 61).
Rotate the core 61 in the direction of pulling it out. Then,
Since the position of the core 61 does not change, the product B is gradually pushed out from the cavity 71 as shown in FIG. Therefore, if the product B has a rectangular shape or has a protrusion, and has a function to prevent the core 61 from rotating while it comes out of the cavity 71, the core 61 will not rotate. However, when approaching the end of a threaded part, product B is almost pushed out from inside the cavity 71, and the rotation prevention function due to the external shape disappears. It becomes impossible to maintain a correct threaded state with the thread forming part (external thread part 62) on the core 61 side. Particularly, since product B is not completely cooled when taking out the molded product, if the above condition occurs, the molded inner wafer b will easily deform, resulting in a defective product. For this reason, conventionally, after opening the movable mold, a bottle or a thin plate (not shown) that receives the molded product from the outside of the mold and supports it against rotation is placed toward the product to be extruded. This prevents damage to the internal threads.

However, due to the use of such a so-called anti-rotation stopper, it is important to contact the end face of the product or its vicinity with the stopper against a product that has not yet sufficiently cooled and hardened. This will cause injuries. Therefore, there are drawbacks that make it difficult to obtain a complete molded product. For this reason, for products with internal threads, particularly those with fine threads, it is necessary to design the shape in advance so that the press damage caused by the pad is not noticeable, which is inconvenient.

In the present invention, these problems have been solved, and the internally threaded core rod can be removed from a naturally formed product without installing a stopper such as a stopper that directly affects the product. The object of the present invention is to provide a mold that allows the product to be quickly removed from the hollow mold.

Means for Solving the Problems: The present invention provides a mold for molding a product having an internal thread: in the internal hole forming part in the molding core of the movable template,
An internally threaded core rod is inserted through the receiving plate so that it can move forward and backward, and a product extrusion piece is fitted onto the outside of the internally threaded core rod and engaged with the ejector plate. The rod is supported by a bearing at its intermediate portion so as to be rotatable and movable in the axial direction, and has a gear attached to its rear end to which rotational force is transmitted.

In addition, in the molding die of the present invention, the rear end of the internally threaded molding core rod is fitted and connected to the rotary power transmission gear so as to be movable in the axial direction, and the molded product is formed after the movable side mold is opened. Even if the internally threaded core rod moves forward when taking it out from the mold, the rotational force can be transmitted. Moreover, a spring is engaged with the rear end of the internally threaded mandrel so that as the internally threaded mandrel is rotated and extracted from the internal threaded portion of the molded product, it is gradually pulled back into the movable molding core. It can be made into an ellipse.

Function: According to the mold of the present invention having an oval shape as described above, when the molded product is taken out after being attached to a molding machine by well-known means and injected with resin, the molded product is removed from the movable side. With the end held in the mold, the internal thread molding core rod can be rotated and removed from the internal thread part, and after the threaded part of the internal thread molding core rod is removed from the product, the mold is fully closed. When the ejector grate is operated, the product is ejected by the extrusion piece.

As described above, according to the present invention, the mold prevents the molded product from rotating without applying a special rotation stopper until the internal thread forming core rod is removed from the threaded part of the molded product. Since the internally threaded core rod can be rotated to achieve the purpose while being held, the product will not be damaged. Of course, operations can be performed quickly, which can help improve work efficiency. Furthermore, even with small threads such as fine threads, products with high precision can be obtained because no excessive pulling force is applied.

In addition, when rotating the internally threaded core rod to remove it from the internal thread of the molded product, the internally threaded core rod rotates while moving in the axial direction, but the rotational power transmission gear On the other hand, if the fitting connection is made to be movable only in the axial direction, there will be no problem at all.

Furthermore, when pulling out the internally threaded core rod from an internally threaded part of a molded product, if a spring force is applied so that a pullback force is applied, the internally threaded core rod can be quickly removed without being tensed. It can be operated and used to improve work efficiency.

Embodiment: The present invention will be described below with reference to an embodiment of the drawings.
It is as follows.

FIG. 1 shows a molding die for a flanged ring with an internal thread that is injection molded using the Bingate method, and l molding parts thereof are shown. FIG. 2 is an enlarged sectional view of the main part. In these figures, 10 is a fixed side mounting plate, 11 is a sublu push, 12 is a locate ring, 13 is a runner stripper plate, and 14 is a fixed side template. 15 is a die shape or core on the fixed side, and a bin gate 1 that connects from the sprue nozzle 11° to the molding part cavity 17 via the runner 16.
8 is provided. Reference numeral 20 denotes a movable mold plate, and a movable mold core 21 is attached coaxially with the fixed mold forming core 15. At the center of this mold core 21,
A cylindrical product extrusion piece 2 in which the internally threaded hollow-shaped core rod 30 and the end face 22 (see Figure 2 on the upper side of the figure) become part of the mold.
2 (but not limited to this) are coaxially inserted and inserted. Reference numeral 23 denotes a receiving plate for the movable mold plate 20, which is integrally attached to the movable mold plate 20 via a spacer 24. 25 is a baser block, 26 is a second receiving plate, 27
28 is the base plate, and 28 is the movable side mounting plate. Also, 29 is a guide bin, 29', 29''' are guide bin pushers, 38 is a return bin, 38° is a return spring,
40 is a core rotation drive mechanism.

The internally threaded core rod 30 is provided with a threaded portion 31 for internal threading on the circumferential surface of its distal end, and the intermediate portion is attached to a slide ball bearing 36 fitted in the spacer block 25. It is supported rotatably and movably in the axial direction. Furthermore, the rear end 32 of the internally threaded core rod 30 is
It is shaped into a square shaft (not limited to this, as long as it is not rotatable), and is rotatable via bearings 44 and 44' on the movable side mounting plate 28 and the second receiving plate 26. The connecting hole 45 of the attachment boss 43 of the chain wheel 41 supported by the chain wheel 41 is slidably connected to be movable in the axial direction. In addition, the internally threaded core rod 3o has a threaded shaft portion 33 provided at the rear end.
The receiving seat piece 35 is screwed and fixed, and a pullback spring 37 is interposed between one side of the receiving seat piece 35 and the end face of the slide ball bearing 36, and the other surface of the receiving seat piece 35 is normally used as the second receiving seat. It is designed to be received by a plate 26. The core rod rotation drive machine $1140 includes a prime mover (generally a reduction motor), which is not shown in the drawings, from a chain wheel on the shaft to the chain wheel 41.
The ellipse is driven by a chain (not shown) wrapped around it via a floating chain wheel 42 so as to rotate only in the direction in which it comes out of the internally threaded part. Reference numeral 50 denotes an ejector plate, which is interposed in a space 55 formed by the spacer 24 between the movable mold plate 20 and the receiving plate 23, and is pulled back by a pull-back spring 52 fitted onto the return bin 51. In the normal state, it is held in contact with the receiving plate 23. The end of the product extrusion piece 22 is connected to its ejector plate 50.
is engaged in. The parts other than those described above are the same tanks as conventional molds.

The molding die configured in this manner is used by attaching the fixed side mounting plate 10 and the movable side mounting plate 28 to a conventionally known molding machine by a well-known means.

The resin is injected into the cavity 17 of the molding die from the injection nozzle of the molding machine through the suble nozzle 11°.

To take out the product after the molding operation, first, remove the block from the fixed side mold plate l4 after the runner stripper plate 13 to the movable side mounting plate 28 by removing the fixed side mounting plate 1 by known means.
By pulling it away from 0, the resin that has been injected from the Suburu nozzle 11' and solidified is separated. Next, by opening the space between the runner stripper plate 13 and the stationary template 14, the resin from the runner 16 and pin gate 18 parts that were connected to the molded product A is removed.

Thereafter, the fixed side mold plate 14 and the movable side mold plate 20, as well as the receiving plate 23 and the spacer block 25 are opened. However, the opening dimension between the receiving plate 23 and the spacer block 25 differs depending on the length dimension of the internally threaded part a. In this state, it becomes as shown in Figure 3. At this point, the product A moves along with the movable mold forming core 21 side. Of course, the internally threaded core rod 30 is in a screwed state with the product A. Further, in this state, the internal thread forming core rod 30 is pulled toward the movable template 20, and the pullback spring 37 interposed between the receiving seat piece 35 and the slide ball bearing 36 is compressed. In conjunction with this mold opening operation, the core rod rotates 8! The oval 40 is operated and the internally threaded core rod 30 is extracted from the internally threaded part a of the product A via the chain wheel 41. On this occasion,
As the internally threaded core rod 30 rotates, it moves in the backward direction, and the thrust of the pullback spring 37 acting on the receiving seat piece 35 actively pulls back the internally threaded core rod 30 accordingly. The end surface of the product A in the mold section is kept in close contact with the end surface 22' of the product extrusion piece 22, and the frictional force thereof prevents the product A from rotating together. Note that the inner core rod 30 is attached to the mounting boss 4 of the chain wheel 41.
Since the three parts are connected so that they can move in the axial direction,
The rotational force is transmitted without any problem even when the inner thread is pulled back from the inner thread forming part a. In this way, the product A is held in the movable mold shape or the core 21 side, and when the threaded part 31 of the internally threaded core rod 30 is removed from the internally threaded part a, the fourth As shown in the figure, it is no longer bound. Therefore, by applying a thrust force from the outside by well-known means, the ejector plate 5 is
By moving the product A forward, the product pushing piece 22 moves forward, as shown in FIG. 5, and the product A is discharged to the outside.

After removing the product in the above order, attach the fixed side mounting plate■0
By moving the movable mounting plate 28 forward relative to the mold, the state shown in FIG. 1 is achieved, and the entire mold is closed. The ejector plate 50 and the product extrusion piece 22 connected thereto are as follows:
A pullback spring 5 provided externally on the return bin 51
2, it is returned to its normal position. Similarly, the internally threaded mandrel 30 is returned to a predetermined position by the pull-back spring 37.

The above explanation has been about the molding part for one product, but in a normal mold that molds multiple products at once, the molding core and internal thread molding core as described above and their The control parts to be operated are arranged at appropriate intervals.

In addition, according to the spirit of the present invention, products with external threads,
It goes without saying that it can also be applied to products that require a split mold, such as products with protrusions in their external shape. Effects of the invention: According to the present invention, when removing the internally threaded molding core from a molded product, the mold can be opened without the need to contact the product with a stopper from outside the mold. At the same time, it is held against rotation and can be pulled out while rotating the internal molding core rod, which prevents damage to the product and enables accurate molding of delicate items such as fine threads. It can be said that it is a useful tool that allows you to easily obtain molded products with high precision and also reduces production costs.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the molding die of the present invention, Fig. 2 is an enlarged sectional view of the main parts, Figs. 3 to 5 are views showing how the molded product is taken out, and Figs. Figure 7 shows an example of the conventional method. 10...Fixed side mounting plate 1
1...Suburu push 11'...Suburu nozzle 13...Runner stripper plate 14...Fixed side mold plate 15...Fixed side mold shape or core 16...Runner 17...Molding part Cavity 18... Bin gate 20... Movable side mold plate 21... Movable side mold shape or core 22... Product extrusion piece 23... Receiving plate 24.27.
・・Subasa-28・・Movable side mounting plate 29・・
・Guide bin 30...Inner thread forming core rod 31...
Threaded portion 32... Rear end of internal thread forming core rod 33... Threaded shaft portion 35... Receiving seat piece 36
...Slide ball bearing 37.38. 52...Retraction spring 38.51...
・Return bin 40... Core rod rotation drive machine oval 41...
・Chain wheel 43...Mounting boss 45...Connection hole 50...Ejector plate 55...
・Space part A... Molded product a...
Internal thread forming part 1 Figure 2 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. In a mold for molding a product having an internally threaded portion: An internally threaded molding core rod is inserted into the internally threaded hole forming portion of the molding core of the movable template from the receiving plate side so as to be freely advanced and retracted. , and a product extrusion piece is disposed externally on the inner threaded core rod and engaged with the ejector plate, and the inner threaded core rod is rotated and moved back and forth in the axial direction by a bearing at the intermediate portion. 1. A mold for forming a synthetic resin product having an internally threaded part, characterized in that the mold is supported as much as possible, and has a rear end equipped with a gear to which rotational force is transmitted. 2. The molded metal of a synthetic resin product having an internal threaded portion according to claim 1, wherein the rear end of the internally threaded core rod is fitted and connected to the rotary power transmission gear so as to be movable in the axial direction. Type. 3. The mold for molding a synthetic resin product having an internally threaded portion according to claim 1, wherein the rear end of the internally threaded molding core rod is biased with an acting force in a pullback direction by a spring.