JP2587349Y2 - Injection mold - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a mold for injection molding.

[0002]

2. Description of the Related Art Conventionally, a first mold member 61 provided with a cavity 62 for molding a product part 32 of a molded article 31 as shown in FIG. A third mold provided with a second mold member 3 provided with a gate 64 and a runner 65 communicating with the cavity 62 and an undercut portion 68 which engages the runner portion 34 of the molded product 31 formed in the runner 65. A member in which a member 66 and a member 66 are stacked in this order so as to freely contact and separate is known. The molded article 31 is made of resin or rubber as a molding material,
And the runner part 34 are integrally connected via a gate part 33. The undercut portion 68 is provided at a lower end of an engagement pin 67 slidably inserted into the third mold member 66.

[0005] FIG. 5 shows a completed state of the molding, and the above-described mold should be operated from this state as follows. The third mold member 66 starts rising alone, and the molded product 31
Is pulled upward because of engagement with the undercut portion 68 in the runner portion 34, and is cut at the gate portion 33. The third mold member 66 continues to rise, and the runner portion 34 is pulled out of the runner 65. The second mold member 63 rises alone. The product portion 32 is protruded from the cavity 62 by the protruding pin 69.

[0004]

However, when the above mold is actually operated, FIGS. 6 and 7 show that the engaging force of the undercut portion 68 is insufficient.
As shown in (5), the engagement between the undercut portion 68 and the runner portion 34 may be disengaged, and the runner portion 34 may remain in the runner 65.

[0005]

SUMMARY OF THE INVENTION In view of the above points, the present invention has been devised to solve the above-mentioned problems in the prior art. A first mold member provided with a cavity for molding
A second mold member provided with a gate and a runner communicating with the cavity, and a third mold member provided with an undercut portion for engaging a runner portion of a molded product molded in the runner, in this order. In a mold for injection molding laminated so as to be able to freely contact and separate from the surface, a concave portion surrounding a part of the runner is provided on a surface of the second mold member on the side of the third mold member, and the concave portion is slid. A member is inserted, the slide member surrounds a part of the runner, and is reciprocally movable toward the third mold member with respect to the second mold member. It is elastically urged by a spring toward the mold member, and has a pair of divided bodies divided in a direction orthogonal to the reciprocating motion, and the pair of divided bodies is the second mold member. Direction away from each other when the mold is opened by the angular pins set up on Providing an injection mold, characterized in that movement is freely.

[0006]

The mold of the present invention having the above-described structure can reduce the force required to peel the runner from the inner surface of the runner by moving the slide member together with the runner at the beginning of the mold opening. It is made smaller, and the elasticity of the spring participates in this force.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS.
A first mold member 1 provided with a cavity 2 for molding a product portion 32 of a molded article 31; and a gate 4 communicating with the cavity 2
And a second mold member 3 provided with a runner 5 and a runner 5.
And a third mold member 6 provided with an undercut portion 8 that engages with the runner portion 34 of the molded product 31 formed in the above. Further, it has the following configuration.

That is, a recess 10 is provided on the upper surface of the second mold member 3 so as to surround a part of the runner 5, and a slide member 11 is inserted into the recess 10. The slide member 11 surrounds a part of the runner 5, is vertically movable with respect to the second mold member 3, is elastically urged upward by a spring 13, and is left and right in FIG. And a pair of divided bodies 11a, 1
1b, and the pair of divided bodies 11a, 11b are formed by a pair of angular pins 1 erected on the second mold member 3.
The molds 4 and 15 are movable in directions away from each other when the mold is opened. Reference numeral 7 denotes an engaging pin, and 9 denotes a protruding pin.

FIGS. 1 and 2 show a completed state of the molding, and the above-mentioned mold operates from this state as follows. The third mold member 6 starts rising alone, and the slide member 11 is pushed by the spring 13 and follows the same, and the molded product 31
Are engaged upward with the undercut portion 8 at the runner portion 34 and are cut upward at the gate portion 33 (FIG. 3). At this time, the runner part 34 is connected to the runner 5
The force required for peeling from the inner surface of the slab is smaller than before because the slide member 11 moves together with the runner portion 34 and the area of the inner surface is smaller than before, and the elasticity of the spring 13 is reduced by this force. In order to participate, the molded article 31 is reliably cut at the gate 33 and the runner 34 is
Is reliably peeled off from the inner surface of the The slide member 11
If the second undercut portion 12 is provided on the inner surface of
The pullout force is even greater. When the third mold member 66 continues to rise, the pair of divided bodies 11a and 11b of the slide member 11
The runners 34 are moved away from each other by the guidance by the guides 4 and 15, and the runner portions 34 are peeled off from the slide member 11 relatively. The third mold member 66 continues to rise further, and the runner portion 34 is pulled out from the inner periphery of the slide member 11. The product portion 32 is projected from the cavity 62 by the projection of the projection pin 9, and the undercut portion 8 is detached from the runner portion 34 by the retraction of the engagement pin 7 (FIG. 4).

Therefore, according to the mold having the above-described structure, the force required to separate the runner portion 34 from the inner surface of the runner 5 by moving the slide member 11 together with the runner portion 34 at the beginning of the mold opening. Was made smaller than before, and the elasticity of the spring 13 participated in this force,
The molded product 31 can be reliably cut at the gate 33, and the runner 34 can be reliably peeled off from the inner surface of the runner 5.

[0011]

[Effects of the Invention] The present invention has the following effects. That is,
By moving the slide member together with the runner part at the beginning of the mold opening, the force required to peel the runner part from the inner surface of the runner is made smaller than before, and the elasticity of the spring participated in this force. In addition, the molded product can be reliably cut at the gate portion, and the runner portion can be reliably peeled off from the inner surface of the runner. Therefore, it is possible to prevent the undercut portion and the runner portion from being disengaged from each other and the runner portion from remaining in the runner as in the related art.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an injection mold according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view of a main part showing the operation of the mold.

FIG. 4 is a sectional view of a main part showing the operation of the mold.

FIG. 5 is a sectional view of a main part of an injection mold according to a conventional example.

FIG. 6 is a sectional view of a main part showing the operation of the mold.

FIG. 7 is a sectional view of a main part showing the operation of the mold.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first mold member 2 cavity 3 second mold member 4 gate 5 runner 6 third mold member 7 engaging pin 8 undercut portion 9 protruding pin 10 concave portion 11 slide member 11a, 11b divided body 12th Second undercut part 13 Spring 14, 15 Angular pin 31 Molded product 32 Product part 33 Gate part 34 Runner part

Claims (1)

(57) [Scope of request for utility model registration] 1. A first mold member (1) provided with a cavity (2) for molding a product part (32) of a molded article (31).
A second mold member (3) provided with a gate (4) and a runner (5) communicating with the cavity (2); and a runner part (31) of a molded product (31) molded in the runner (5). And a third mold member (6) provided with an undercut portion (8) engaged with the third mold member (34). The third mold member (6) of (3).
A recess (1) surrounding a part of the runner (5)
0), and a slide member (11) is provided in the recess (10).
The slide member (11) surrounds a part of the runner (5) and faces the third mold member (6) with respect to the second mold member (3). And is resiliently urged by a spring (13) toward the third mold member (6), and is divided into two in a direction orthogonal to the reciprocation to form a pair of divided bodies (11a). (11b), and the pair of divided bodies (11a) (11b) are angular pins (14) (1) erected on the second mold member (3).
5) An injection molding die, which is movable in a direction away from each other when the mold is opened.