JPS6350092Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a sealing mechanism when vacuum pressing rubber products such as O-rings with a mold.
The purpose is to simplify the configuration of the vacuum hood to make it easier to take the mold in and out, and to allow for free strokes. Part of the purpose of the present invention is to improve sealing performance, durability, and workability for attaching and detaching.

First, a conventional example will be explained. In Figure 1, which shows a part of the vertical cross section, 1 and 2 are the lower mold and the upper mold (mold).
The lower mold 1 is attached to a predetermined position on the upper surface of a slide plate 3 (lower mold holder), and the slide plate 3 is supported on a heating plate 4 and heated to, for example, 180°C.
The upper die 2 is attached at a predetermined position on the lower surface of an upper die holder 5 on the side of the press machine. Reference numerals 6 and 7 designate frame-cylindrical hoods (slide frames) forming a vacuum hood, and the hood 6 surrounds the mold 1 as shown in FIG. 2 and is fixed onto the slide plate 3 with a plurality of bolts 8. The hood 7 surrounds the hood 6 with a gap 9 in between, and is fixed to the upper die holder 5. Reference numeral 10 denotes an annular rubber gasket, which is fastened to the lower end surface of the hood 7 with a bolt 12 via a gasket retainer 11.
The inner peripheral lip portion 10a is in pressure contact with the outer peripheral surface of the hood 6 over the entire circumference.

When manufacturing O-rings, etc., feed the material between the upper and lower molds 2 and 1 with the mold open, with the hood 7 sufficiently spaced above the hood 6, then place the upper mold 2 on the lower mold 1, and remove the hood. A space 13 surrounded by 6 and 7 is evacuated, and the material is vulcanized and formed by heat from the hot platen 4.

However, according to the structure shown in FIG. 1, the hood 6 (vacuum slide frame) is fixed to the slide plate 3 on the side of the heating platen 4, which obstructs the attachment of the mold and the loading and unloading of materials and products. Also, because of the vacuum seal, the lip faces in the opposite direction to the slide, causing the lip to bounce back, which may damage the seal or reduce the degree of vacuum.

Conventionally, the structure shown in FIG. 3 is also known. In FIG. 3, the inner cylindrical slide frame 15 has an O-ring 16 on its lower end surface, and a bolt 18 that also serves as a guide passes through a hole at the tip of an arm 17 protruding from the outer peripheral surface near the lower end. An adjuster nut 19 is screwed onto the mold holder 5 and protrudes downward from the arm 17, and due to the elasticity of the coil spring 20 compressed between the arm 17 and the upper mold holder 5, the O-ring 16 is moved to the slide plate 3. It is pressed against the top surface of the Reference numeral 21 designates an outer cylindrical slide frame whose upper end is fixed to the upper mold holder 5, and an O-ring 22 attached to the lower end of the inner circumferential surface is in pressure contact with the outer circumferential surface of the slide frame 15. FIG. 3 shows the middle of the process of fitting the molds in the same way as in FIG. It descends while sliding on the surface.

According to the structure shown in Fig. 3, the inner and outer slide frames 15, 2
The structure of the vacuum hood made of 1 becomes complicated and difficult to lower. Furthermore, there is a limit to the vertical stroke, which limits its uses.

The present invention attempts to solve the above problem by attaching a gasket made of heat-resistant rubber to the lower die holder, and an embodiment thereof is shown in FIG. 4.

In FIG. 4, the peripheral edge of the upper surface of the slide plate 3 is cut into a rectangular section to form a stepped portion 25, and an annular packing 26 made of a specially formulated soft rubber is placed on this stepped portion 25. It is fastened to the stepped portion 25 with a plurality of bolts 28. Tip lip portion 26a of packing 26
is outside the outer periphery of the slide plate 3 (left side in Figure 4)
It protrudes to
The position of the stepped portion 25 and the thickness of the gasket 26 are determined so that neither of the two protrudes upwardly from the upper surface of the slide plate 3.

29 is a cylindrical hood whose upper end is fastened to the upper mold holder 5 with bolts 30, and whose inner peripheral surface 31
is inward from the tip of the lip portion 26a (right side in Figure 4)
A tapered surface ₃₂ that smoothly expands outward as it goes downward is formed at the lower end of the inner circumferential surface.

Figure 4 shows the middle of the process of matching the molds.
When the upper mold holder 5 is lowered from this state, the tapered surface 32 comes into pressure contact with the packing lip 26a, and then the hood inner surface 31 comes into pressure contact with the packing lip 26a, thereby sealing the space 13. Continued upper and lower type 2,
1 are put together, the inside of the space 13 is drawn to a vacuum state, and vacuum press molding is performed. When the upper mold holder 5 is raised to open the mold, the hood 29 is moved sufficiently upwardly from the gasket 26, and the space 13 is opened to the outside. When replacing lower mold 1, replace lower mold 1.
can be slid horizontally on the slide plate 3.

As explained above, in the present invention, a lower step 25 is provided at the upper peripheral edge of the lower mold holder 3, and the tip lip 26a of the outer periphery of this step 25 protrudes laterally from the side surface of the lower mold holder 3. The heat-resistant annular packing 26 is pressed against the packing presser 27 on the upper side,
A cylindrical hood 29 is attached to the upper mold holder 5 so as not to protrude upwardly from the lower mold holder 3 together with the tightening bolt 28, and a heat-resistant annular packing 26 is inscribed in the upper mold holder 5 when the mold is separated from the lower mold holder 3 when the mold is assembled. (1) The configuration of the vacuum hood is simplified;
One hood 29 is enough. (2) Strokes can be taken freely. (3) Easier to put in and take out the mold. (Four)
Even fairly thin molds can be easily installed. (5) Since the volume of the space 13 is reduced, the degree of vacuum in the space 13 is improved, and problems such as poor material flow, voids, and mold stains are significantly reduced. (6) During mold matching when the cylindrical hood 29 is lowered, the tip lip portion 26a of the heat-resistant annular packing 26 is pushed downward by the inner surface 31 of the cylindrical hood 29 and is deformed into a downward-hanging state while moving toward the slide plate 3 side. When the mold space 13 is compressed and then the degree of vacuum in the mold space 13 is increased from that state, the upper surface of the tip lip portion 26a, which is curved downward, receives vacuum pressure, and the tip lip portion 26a is pressed against the inner peripheral surface of the cylindrical hood. 31 and is slightly deformed upward on its own, and at this time, the tip lip portion 26a is further compressed toward the slide plate 3 side, and the tip lip portion 2a6 and the inner circumferential surface 3
The surface pressure of No. 1 is increased, and the sealing performance is improved. (7) In general, the durability of packing at high temperatures is low when the packing is in tension, and high when it is in compression.
In this respect, according to the present invention, the packing 26 receives heat from the sliding plate 3 because the sliding plate 3 is heated to, for example, 180°C by the heating plate, but when the mold is closed and vacuum press is performed, the tip lip portion 26a is attached to the cylindrical hood 2.
The degree of compression increases due to the synergistic effect of the pressing force from 9 and the vacuum in space 13, and heat resistance increases.
Moreover, the tip lip portion 26a is located on the high temperature slide plate 3.
Since it protrudes laterally from the side surface, the amount of heat transfer is reduced, and this surface also reduces the heat load on the tip lip portion 26a. (8) Furthermore, according to the present invention, the workability of attaching and detaching the heat-resistant annular packing 26 is improved. That is, when installing a new gasket 26, the gasket 26 can be temporarily fixed and positioned simply by placing it on the stepped portion 25, and then the gasket presser 27 can be placed on top of it and the bolt 28 can be tightened. At this time, since no assembly jig is required, the packing can be installed even by non-experts. (9) The packing holder 27 protects the packing 26 when the mold is attached or removed.

When the present invention is implemented, various rubber-like elastic bodies having heat resistance of 190° C. or higher, for example, can be used as the packing 26.

[Brief explanation of drawings]

FIGS. 1 and 3 are longitudinal cross-sectional partial views showing conventional examples;
FIG. 2 is a partial view taken in the direction of the - arrow in FIG. 1, and FIG. 4 is a partial vertical cross-sectional view of a vacuum press apparatus to which the present invention is applied. 3...Slide plate (lower die holder), 5...Upper die holder, 26...Heat-resistant annular packing, 29...
...Cylindrical hood.

Claims (1)

[Scope of utility model registration request] A lower step 2 on the periphery of the upper surface of the lower mold holder 3
5 is provided, and this stepped portion 25 has a tip lip portion 2 on the outer periphery.
A heat-resistant annular packing 26 having a part 6a projecting laterally from the side surface of the lower mold holder 3 is attached together with the packing presser 27 and the tightening bolt 28 above the lower mold holder 3 so as not to protrude above the upper mold holder 5.
A sealing mechanism for a vacuum press apparatus, characterized in that a cylindrical hood 29 is attached to the lower mold holder 3 when the mold is opened, and a heat-resistant annular packing 26 is inscribed therein when the molds are put together.