JPH0736731Y2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a slide pin drive mechanism for forming an undercut portion in an injection molding die.

(B) Conventional technology When forming an undercut portion on a molded product, if it is a local one and is undercut simply because it is inclined with respect to the mold opening direction, It is often processed by the inexpensive slide pin method. Examples of the apparatus include those shown in Japanese Utility Model Laid-Open No. 58-160124 and those shown in Japanese Utility Model Laid-Open No. 59-5318.

The one disclosed in Japanese Utility Model Laid-Open No. 58-160124 is driven by a link mechanism because a drive pin for moving a slide pin is projected on the die mating surfaces of a fixed die and a movable die. A device for reversing the direction is required, which complicates the mechanism. Further, in the method of driving the slide pin on the die mating surface as described above, it is necessary to provide the drive pin in a limited area of the outer periphery of the molding portion of the die mating surface, and the outer peripheral strength of the die becomes weak. Further, there is a problem in that the size and shape of the molded product are regulated and the degree of freedom in designing the mold is lacking. Also, the one disclosed in Japanese Utility Model Laid-Open No. 59-5318 has a complicated mechanism because the driving direction is changed by using a slide base, a cam, or the like.

As described above, the conventional technique has a complicated mold structure and has a problem in designing the mold.

(C) Problems to be Solved by the Invention The present invention solves the above-mentioned drawbacks, and by providing a simple hitting means between the base part of the movable mold and the slide pin base end, The simple mechanism ensures the desired operation of the slide pin.

(D) Means for Solving the Problems In the present invention, the movable mold is provided with a slide hole communicating with the cavity and inclined with respect to the mold opening direction, and a slide pin having a mold surface at the tip is inserted into the slide hole. Then, insert a compression coil spring between the slide pin and the movable mold, which gives a biasing force to the slide pin in the retracting direction, and insert a mold coil between the base of the movable mold and the slide pin base end during mold clamping. The relative movement of the ejector plate and the base of the movable mold applies a force in the mold clamping direction from the base end side of the slide pin to provide a hitting means for advancing the slide pin to the molding position.

(E) Action When the mold is opened after molding and the molded product is ejected, the slide pins also adhere to the molded product and try to come out of the movable mold, but the movement is braked by the urging force of the compression coil spring in the retracting direction. As a result, the slide pin separates from the molded product.
The slide pin hits the hitting means by the retracting biasing force of the compression coil spring and stops. The slide pin is pushed up by the hitting means located between the base portion of the movable mold and the base end of the slide pin to accurately return to the molding position when the mold is clamped.

(F) Embodiment In the drawings, 1 is a movable mold, and 2 is a base part for attaching this to an injection molding machine. The molded product 3 is molded in the cavity 4 between the fixed mold (not shown) and the movable mold 1. Reference numeral 5 is an ejector plate, and 6 is an ejector pin.

The movable mold 1 is provided with a slide hole 7 communicating with the cavity 4 and inclined with respect to the mold opening direction, and a slide pin 8 is inserted therein. The tip of the slide pin 8 is a mold surface 9, whereby an inclined boss-shaped undercut portion 10 is formed on the back surface of the molded product. The slide pin 8 has flange portions 11 and 12 at the intermediate portion and the base end portion, respectively. A compression coil spring is provided between the flange 11 and the movable mold 1.
13 is inserted. The flange portion 12 is the ejector plate 5
It goes into the dovetail groove 14. Reference numeral 15 is a hit pin interposed between the base end of the slide pin 8 and the base portion 2. The hit pin 15 is in the form of a rivet, the head is abutted against the slide pin 8 in the dovetail groove 14, and the shaft part penetrates the ejector plate 5 and hits the base part 2.

The above operation causes the following operation. FIG. 1 shows the state during mold clamping. Slide pin 8 has flange 12 and groove
It is held in the molding position by being sandwiched between 14 ceilings and hit pins 15. The hit pin 15 is pushed up by the base portion 2,
Hold the slide pin 8 in the molding position. The compression coil spring 13 has not yet exerted the retracting biasing force on the slide pin 8 at this time. When the ejector plate 5 starts moving as shown in FIG. 2, the slide pin 8 initially adheres to the molded product 3 and advances, but eventually the compression coil spring 13 is moved to the movable mold 1.
Then, the brake is applied to the movement of the slide pin 8. As the ejector plate 5 continues to move forward, the relative retracted amount of the slide pin 8 increases, and the slide pin 8 comes off the molded product 3 as shown in FIG.
It retreats by the retracting urging force of 13, hits the hit pin 15, and stops. When the mold is clamped after taking out the molded product 3, the slide pin 8 is pushed back to the molding position of FIG.

(G) Effect of the Invention According to the present invention, it is possible to cause the slide pin to perform an intended operation only by providing a hitting means between the base part of the movable mold and the base end of the slide pin. Can be simplified. Further, since the driving means (abutting means) for driving the slide pin is not provided on the die mating surface, the outer peripheral strength of the die can be maintained, and the design of the die molding portion is not affected by the means and can be freely set. The effect is that it can be designed.

[Brief description of drawings]

1 to 3 are sectional views showing an embodiment of the present invention and show different operating states. 1 ... Movable mold, 2 ... Base part, 3 ... Molded product, 4 ...
... Cavity, 5 ... Ejector plate, 7 ... Slide hole, 8 ... Slide pin, 9 ... Mold surface, 13 ... Compression coil spring, 15 ... Contact pin (contact means).

Claims (1)

[Scope of utility model registration request] 1. A movable mold is provided with a slide hole communicating with a cavity and inclined with respect to a mold opening direction, and a slide pin having a mold surface at a tip thereof is inserted into the slide hole, the slide pin and the movable mold. A compression coil spring that applies a biasing force to the slide pin in the retracting direction is inserted between the slide pin and the ejector plate and the base part of the movable mold between the base part of the movable mold and the slide pin base end during mold clamping. An injection molding die provided with a hitting means for advancing the slide pin to a molding position by applying a force in the mold clamping direction from the base end side of the slide pin by relative movement with the slide pin.