AU699359B2 - Molding tool for a rubber molded product - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

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p 5*4o Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Toyoda Gosei Co., Ltd.

1, Nagahata, Ochiai, Haruhi-cho Nishikasugai-gun Aichi-ken

JAPAN

Michihiro Suzuki, Tatsuhiko Nagata and Tomoji Yamashita Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Molding Tool for a Rubber Molded Product i The following statement is a full description of this invention, including the best method of performing it known to me/us:- MOLDING TOOL FOR A RUBBER MOLDED PRODUCT BACKGROUND OF THE INVENTION The present invention relates to a molding tool for a rubber molded product having a through hole, which is suitable for the formation of, for example, a weather strip having a drain hole as a through hole.

A roofside weather strip 1 such as shown in Fig. 7 is known in the art. The roofside weather strip 1 is mounted to the roof of an automobile body in the periphery of a door opening, and comprises a hollow portion 3 and a lip portion 4 so as to make contact with window glass 2 of a sashless door at two positions. A drain groove 5 is formed between the hollow portion 3 and the lip portion 4, and a drain hole 6 which communicates with the interior of the hollow portion 3 is formed in an end portion of the drain groove 5. Water entering inside the door is discharged to the exterior of the cabin from the rear portion of the door opening via the drain hole 6 and the hollow portion 3. Such a drain structure o-f roofside weather strip is known in, for example, Japanese Patent S0 Unexamined Publication (Kokai) No. Sho. 63-235143.

Conventionally, the roofside weather strip 1 is .olded by a molding tool such as shown in Fig. 8. The molding tool 31 comprises an inner mold 32 for forming the inner face of the hollow portion 3, and an outer mold 33 for forming a body mounting face 3a of the hollow portion 3, the lip portion 4, and the drain groove 5. The inner mold 32 is provided with a projection 32a for forming the drain hole 6. The outer mold 33 1 is split into three parts, a lower mold 34, an upper mold I and an intermediate mold 36. The projection 32a butts against a butted portion of the intermediate mold 36. A rubber material is injected around the projection 32a, and the projection 32a is then pulled out from the rubber material, thereby forming the drain hole 6 in the roofside weather strip i.

Depending on the mold accuracy, a gap of, for example, about 0.02 to 0.06 mm may be formed between the butted portion of the intermediate mold 36 and the projection 32a. In the prior art molding tool 31, therefore, it sometime happens that the sr material enters the gap via the periphery of the projection 32a to form a thin-film like burr 37 shown in Fig.

9 and the burr 37 completely clogs the drain hole 6. In a finishing step, such a burr 27 easily fails to be detected because the burr 37 has a thin-film like shape. Even in the case where such a burr is detected, when the burr is removed by, for example, tearing off the burr, the burr is often broken at some midpoint so that the burr partly remains on the strip.

20 Consequently, the work of removing such a burr is very t t cumbersome.

44 4 .i :SUMMARY OF THE INVENTION It is an object of the invention to provide a molding tool for a rubber molded product in which, even when a burr is formed in a process of producing a rubber molded product having a through hole, the through hole is prevented from being completely clogged by the burr, thereby allowing ati least the -2 I L- I r,.

-i i major portion of the through hole to be opened, and the work of removing the burr can easily be conducted.

In order to solve the problems, the invention provides a molding tool for a rubber molded product in which a projection of a second mold butts against a butted portion of a first mold, a rubber material is injected around the projection, and the projection is pulled out from the rubber material, thereby forming a through hole in the molded product, and characterized in that a space is formed between the butted portion of the first mold and the projection of the second mold, the space storing the rubber material entering an interface between the butted portion and the projection.

Preferably, at least one of the first and second molds is a slide mold which can slide in a direction which is 04.o :15 substantially perpendicular to a direction of the butting of 0o: S.

the butted portion and the projection.

o o As the space, for example, either of the followings may be employed.

A recess is formed in the butted portion of the first mold.

90 A space is formed between the recess and the projection of the o i second mold. The space may have one of the following structures.

oem e A structure in which the projection of the second mold enters halfway the recess of the first mold.

A structure in which the opening edge of the recess of the first mold coincides with the tip end edge of the projection of the second mold and the projection does not enter the recess.

-3- 1: ~:*31~llCI~ 31i 1 BRb=1=P*aRslar~l lll I- an~ The opening of the recess of the first mold is smaller in area than the tip end face of the projection of the second mold and the projection does not enter the recess.

A recess is formed in the tip end face of the projection of the second mold. A space is formed between the recess and the butted portion of the first mold.

Also in the molding tool of the invention, depending on the mold accuracy, a gap may be formed between the butted portion of the first mold and the projection of the second mold i0 so that the rubber material injected around the projection enters the gap. However, the rubber material entering the gap then enters the space formed between the butted portion of the first mold and the projection of the second mold, and stays therein. Since the amount of the rubber material entering the 15 space is small, the entering rubber material adheres only to 0 the peripheral edge portion of the space so as not to fill the .040 e space but to form a thick burr. Consequently, there is no possibility that the through hole which is formed in the molded product as a result of pulling out the projection is completely .o0 closed. At least the major portion of the through hole can be 0 0* S p Sopened. Such a thick burr can easily be detected in a o, finishing step, and removed easily and surely by, for example, S: tearing off the burr.

In the configuration wherein at. least one of the first and second molds is a slide mold which can slide in a direction which is substantially perpendicular to a direction of the butting of the butted portion and the projection, when the slide mold is slid in a mold releasing process, a burr is -4automatically cut of f by the shearing action exerted by the combination of the butted portion of the first mold and the projection of the second mold. Accordingly, the work of manually removing a burr after the mold releasing process is not required.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a section view showing a molding tool of a first embodiment of the invention.

Fig.- 2 is a section view of a roof side weather strip molded by the molding tool of Fig. 1.

Fig. 3 is a section view showing the main portion of a molding tool of a second embodiment of the invention.

Fig. 4 is a section view showing the main portion of a molding tool of a third embodiment of the invention.

Fig. 5 is a section view showing the main portion of a molding tool of a fourth embodiment of the invention.

:4 Fig. 6 is a section view showing a molding tool of a fifth embodiment of the invention.

4Fig. 7 is a perspective view of a roof side weather 2~0 strip.

r 4:0. ~Fig. 8 is a section view of a conventional molding tool.

Fig.- 9 is a section view of a roof side weathea: strip molded by the conventional molding tool.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, preferred embodiments of the,-present invention will be described with reference to the d4r611ngs.

The weather strip 1 of Fig. 7 which is to be molded by the embodiments, as described above, comprises the hollow portion 3 and the lip portion 4 so as to make contact with window glass 2 of a sashless door at two positions, the drain groove 5 formed between the portions, and the drain hole 6 (corresponding to the through hole in the invention) which communicates with the interior of the hollow portion 3 and is formed in an end portion of the drain groove I Fig. 1 shows a molding tool 11 of the first embodiment, S and Fig. 2 shows a roof side weather strip 1 molded by the molding tool 11. The molding tool 11 comprises an inner mold 12 (corresponding to the second mold of the invention) for forming the inner face of the hollow portion 3, and an outer mold 33 for forming a body mounting face 3a of the hollow :15 portion 3, the lip portion 4 and the drain groove 5. A o1 4* projection 12a for fonr the drain hole 6 is projected from the inner mold 12 by a height which is greater than the depth 0 of the drain hole 6. The outer mold 13 is split into three parts, a lower mold 14 for forming the body mounting face 3a, 0 an upper mold 15 for forming the lip portion 4, and an *o intermediate mold 16 (corresponding to the first mold of the invention) for forming the drain groove 5. A recess 16a which the projection 12a enters halfway so as to be fitted into is formed in the intermediate mold 16. A space 18 for storing an entering rubber material is formed between the recess 16a and the projection 12a.

Also in the thus configured molding tool 11 of the embodiment, depending on the mold accuracy, a gap may be formed 6 I between the intermediate mold 16 and the projection 12a of the inner mold 12 so that the rubber material (generally, EPDM rubber) injected around the projection 12a enters the gap.

However, the rubber material entering the gap then enters the space 18 and stays therein. Since the amount of the rubber material entering the space is small, the entering rubber material adheres only to the peripheral edge portion of the space 18 so as to form a thick annular burr 17, and not to fill the space 18. As shown in Fig. 2, therefore, the drain hole 6 which is formed in the roofside weather strip 1 as a result of pulling out the projection 12a is prevented from being completely clogged by the burr 17, and at least the major portion of the drain hole 6 can be opened. The burr 17 has a cylindrical portion 17a protruding from the drain hole 6 so as 1 15 to have a thick annular shape. Consequently, the burr can s e easily be detected in a finishing step, and removed easily and o*o surely by, for example, tearing off the burr.

ao Fig. 3 shows the main portion of a molding tool 22 of a second embodiment. The molding tool 22 is the same as the 0o °20 first embodiment except that the opening edge of the recess 16a of the intermediate mold 16 coincides with the tip end edge of e 4 S the projection 12a of the inner mold 12 so that the projection 4 4 .o 12a does not enter the recess 16a, and the space 18 is formed between the recess 16a and the projection 12a.

Fig. 4 shows the main portion of a molding tool 23 of a third embodiment. The molding tool 23 is the same as the first embodiment except that the opening of the recess 16a of the intermediate mold 16 is smaller in area than the tip end face 7 c i of the projection 12a of the inner mold projection 12a does not enter the recess 16a is formed between the recess 16a and the pr Fig. 5 shows the main portion of a mo fourth embodiment. The molding tool 24 i first embodiment except that the intermedia provided with a recess, a recess 19 is forn face of the projection 12a of the inner mold 18 is formed between the recess 19 and the 16.

Also the second, third, and fourth mol and 24 can attain the same effects as th embodiment.

Fig. 6 shows a molding tool 25 of a 15 The molding tool 25 is the same as the second that the intermediate mold 16 is a slide mo i in a direction substantially perpendicular the butting of the intermediate mold 16 a 12a.

i .'20 The molding tool 25 of the fifth embc 00 oI the following effect in addition to the same a6 I. f of the first embodiment. When the intermedia in a mold releasing process, the burr 17 is i m 12 so that the ,and the space 18 ojection 12a.

lding tool 24 of a s the same as the Ite mold 16 is not ned in the tip end 12, and the space intermediate mold .ding tools 22, 23, lose of the first fifth embodiment.

embodiment except Ld which can slide to a direction of .nd the projection odiment can attain e effects as those Ite mold 16 is slid automatically cut off by the shearing action exerted by the combination of the intermediate mold 16 and the projection 12a of the inner mold 12. Accordingly, the work of manually removing a bur= after the mold releasing process is not required.

8 The invention is not restricted to the configuration of the embodiments described above, and may be embodied variously by modifying the embodiments without departing from the scope of the sprit of the invention in, for example, the following manner: In the embodiments, the outer mold 13 is split into three parts. Depending on the shape of the lip portion 4, alternatively, the outer mold may be split into two parts.

The invention may be embodied as a molding tool for another kind of a weather strip such as that for a door or a trunk.

The invention may be embodied as a molding tool for a rubber molded product other than a weather strip. The through hole is not restricted to a drain hole.

As described above in detail, the present invention can 5 attain excellent effects that, even when a burr is formed in a n process of producing a rubber molded product having a through o. hole, the burr is prevented from completely closing the through o0 ~alo hole, thereby allowing at least the major portion of the through hole to be opened, and that the work of removing the 0. 20 burr can easily be conducted.

In addition to the effects described above, the present ~invention can attain an excellent effect that a burr can g automatically be cut off in a mold releasing process, thereby eliminating the work of manually removing a burr after the mold releasing process.

9

Claims (2)

1. A molding tool for a rubber molded product, 2 comprising: 3 a first mold having a butted portion; 4 a second mold having a projection whcih is to be butted against said butted portion of said first mold, wherein a 6 rubber material is injected around said projection, and said 7 projection is pulled out from said rubber material to form a 8 through hole in said molded product; and 9 a space formed between said butted portion of said first mold and said projection of said second mold, said space 1i storing said rubber material entering an interface between said 12 buttec porLion and said projection. i

2. A molding tool for a rubber molded product according 000 -2 to claim 1, wherein at least one of said first and second molds 3 is a slide mold which can slide in a direction which is substantially perpendicular to a butting direction of said 0 0 0 0 butted portion and said projection. 0 4 444 DATED this TWENTY-SIXTH day of OCTOBER 1995 0 0 0Toyoda Gosei Co., Ltd. Patent Attorneys for the Applicant/Nominated Person 44a SPRUSON FERGUSON 0 10 I Molding Tool for a Rubber Molded Product Abstract An inner mold (12) is provided with a projection (12a) for forming a drain hole An outer mold (13) is split into three parts, a lower mold an upper mold and an intermediate mold In the intermediate mold (16) for forming a drain groove a recess (16a) which the projection (12a) enters and fitted into is formed. A space (18) for storing an entering rubber material is formed between the recess (16a) and the projection (12a). The entering rubber material adheres only to the peripheral edge portion of the space (18) so as to form a th! k annular burr and not to fill the space (18). Soo 00 a .g. oo ••96 0 0 00 0 0 JED/3821W