JPH03281332A - Manufacturing device for extrusion molding - Google Patents

Abstract

PURPOSE:To finish beautifully a cut surface of a removal part by making the cutting quality of a blade favorable, by a method wherein a section of the blade of a cutter is formed into a streamline and the blade is constituted so that the blade is capable of making rocking and displacement centering around a shaft meeting at right angles with a forward or backward movement action direction of the cutter. CONSTITUTION:An extrusion-molded product having a fixed sectional form is extrusion- molded by extruding a molding material through a mouth piece of an extrusion head. Then a part of the extrusion-molded product which is directly after molding is removed by causing a cutter 1 arranged on a front side of the mouth piece to perform a forward or backward movement action within a plane which is parallel with the front of the mouth piece. In this instance, a section of the blade 3 of the cutter 1 is formed into a streamline and the blade 3 is constituted so that the blade 3 becomes capable of making rocking and displacement centering around a shaft meeting at right angles with a forward or backward movement action direction of the cutter 1.With this construction, since the blade 3 of the cutter 1 changes autonomously a direction in the direction where resistance is reduced as low as possible by resistance between the blade 3 of the cutter 1 and the extrusion-molded product which is directly after molding, a favorable cut surface is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for extrusion molding an extrusion molded product having a uniform cross section, such as a weather strip for an automobile.

2. Description of the Related Art For example, as shown in FIG. 4, a weather strip 30 for an automobile having a hollow lip 31 and a seal lip 32 is manufactured by extruding a rubber material together with a core bar 33 from an extrusion head of an extruder. After extruding an intermediate molded product 34 as an extrusion molded product as shown in FIG.
By bending the welt portion 35 into an abbreviated shape in a subsequent pending step, the product shape shown in FIG. 4 is completed.

In such a weather strip 30, as shown in FIG. 4, the clean groove 36 of the welt portion 35 is fitted into the flange portion 38 of the vehicle body panel 37, and the seal lip 32 is brought into elastic contact with the vehicle body panel 37 at the same time. Weather
The strip 30 is supposed to perform its original function, but due to functional or design constraints on the vehicle body panel 37 side, a part of the seal lip 32 is cut out in an arc shape as shown in FIG. It may be necessary to form part 39.

In such a case, as shown in FIG. 8, a cutter 44 consisting of a holder 42 and a blade 43 is arranged on the front side of the extrusion head 400 and the die 41 through which the intermediate molded product 34 is extruded, and the cutter 44 is connected to the guide member 45. A portion of the seal lip 32 is removed as shown in FIG. 6 by causing the drive unit 46 to move the rear side forward in the direction of the arrow while guiding the seal lip 32. Blade 43 of cutter 44
is formed to have a streamlined cross-section as shown in FIGS. 9 and 10. Note that an opening 47 corresponding to the cross-sectional shape of the intermediate molded product 34 is formed in the base 41.

That is, the cutter 44 is fed in the direction of the arrow at a predetermined timing and speed in synchronization with the extrusion operation of the intermediate molded product 34 from the die 41 in FIG. As a result, as shown in FIG. 7, the seal lip 32 immediately after extrusion molding
The blade 43 of the cutter 44 is a, b, c, d, e,
f, and after a predetermined time elapses, the blade 43 is pulled out from the seal lip 32 again, and a part of the seal lip 32 is cut off in an arc shape as shown in FIG. (Disclosed in JP-A-59-114040 and JP-A-61-230930).

Problems to be Solved by the Invention In the conventional structure, the blade 43 of the cutter 44 is fixed to the holder 42, so as is clear from FIG. The direction of the blade 43 does not change at all until it comes out. Therefore, if part of the blade 43 gets into the seal lip 32, there will be no problem, but
Since a large resistance is applied when the blade 43 enters the seal lip 32 and when the blade 43 is extracted from the seal lip 32, the sharpness is particularly poor at the starting end 39a and the ending end 39b of the cutout 39 (FIG. 6). As a result, a good force gutter surface cannot be obtained, and no improvement in appearance quality can be expected. In particular, as soon as the intermediate molded product 34 is removed from the opening 47 of the base 41, it is released from the restraint of the opening 47 and expands (
(referred to as die swell), the above-mentioned phenomenon is remarkable at the starting end 39a of the cutting portion 39 into which the blade 43 enters immediately after exiting the opening 47.

The present invention was made in view of the above problems.
The purpose is to provide a structure that allows good force and throat surface to be obtained at the cut portion by minimizing the resistance when cutting out a part of the extrusion molded product with a cutter. It is in.

Means for Solving the Problems The present invention extrudes a molding material from a die of an extrusion head to extrude an extrusion molded product having a predetermined cross-sectional shape, and a cutter placed on the front side of the die is moved to a plane parallel to the front face of the die. In this apparatus, a part of the extruded molded product immediately after molding is cut by moving the forward and rear sides of the cutter inside the cutter. It is characterized by being configured so that it can be oscillated around an axis perpendicular to the direction as the center of rotation.

According to the structure described in Section 2, the cutter blade automatically changes direction in the direction that minimizes the resistance due to the resistance between it and the extruded product immediately after being formed, resulting in a good cutting surface. or you will be able to get it.

Embodiment FIGS. 1 and 2 are diagrams showing an embodiment of the present invention, in which a cutter 1 consisting of a holder 2 and a blade 3 with a streamlined cross section is connected to the holder 2 with a hollow shaft made of an insulator. 4, while the hollow shaft 4
A nichrome wire 5 for heating the blade 3 is inserted inside the blade.

That is, a hollow shaft 4 is inserted and fixed into a portion of the blade 3 near the cutting edge 6, and both ends of the hollow shaft 4 are rotatably inserted and supported by the legs 7 of the holder 2 as bearings, while the hollow shaft 4 is Both ends of the nichrome wire 5 inserted into the wire 4 are connected to a power source (not shown) via a terminal plate 8 which is pressed into contact with the wire. Therefore, the blade 3 is heated by the electrothermal action of the nichrome wire 5.

According to such a structure, as shown in FIG.
The cutter 1 is fed downward in synchronization with the extrusion of the intermediate molded product 34 from the sealing lip 3.
2, the center of rotation of the blade 3 is located closer to the cutting edge 6 than the rear end, so the vicinity of the cutting edge 6 is strongly pressed against the freshly formed seal lip 32, as shown in FIG.

When the blade 3 is pressed against the seal lip 32, in addition to the above-mentioned feeding, due to the frictional resistance between the blade 3 and the seal lip 32 due to extrusion molding, the blade 3 is tilted in a direction where the resistance is reduced, that is, in a forward tilted posture. The seal lip 32 smoothly rotates and displaces autonomously (state a in Figure 3).
the seal lip 3 from the starting end 39a in FIG.
2. Start the cutting operation.

Once the blade 3 partially enters the seal lip 32, the blade 3 autonomously moves in a direction that reduces the resistance associated with cutting due to the amount of feed given to the blade 3 and movement with the seal lip 32 due to extrusion molding. The seal lip 32 (7) cutting operation progresses while changing the direction (see Fig. 3).
c, d conditions).

Then, when the blade 3 passes the deepest part of the cutting part 39,
The blade 3 is now given an upward feed instead of the previous downward feed, but at this stage the blade 3 is gradually rotated to a backward tilted position, and eventually remains in a backward tilted position. The extractor comes out from the seal lip 32 and the seal lip 3
The cutting operation of step 2 is completed (e+f+g in Fig. 3).
+h condition).

Here, in the process of cutting off the seal lip 32 as described above, the blade 3 itself is made of nichrome so that the temperature of the blade 3 is several tens of degrees higher than the temperature of the intermediate molded product 34 immediately after extrusion molding. Since it is heated by the wire 5, there is a temperature difference as mentioned above, and the force of the cutting part 39 due to the heating action of the blade 3 is increased due to the effect of accelerating vulcanization on the front surface. Sharpness is further improved.

Effects of the Invention As described above, according to the present invention, the blade of the cutter is configured to be able to be oscillated, so that during the cutting process of the resected portion, the blade is autonomously oscillated in the direction that reduces the resistance associated with the cutting. As a result, the sharpness is better than before, and the surface of the cut section is finished neatly, which can greatly contribute to improving the appearance quality of the cut section.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention, and is an enlarged perspective view of the main part of a cutter, and FIG. 2 is a perspective view showing details of the main part of FIG. 1.
FIG. 3 is an explanatory diagram showing the relationship between the intermediate molded product and the blade;
FIG. 4 is a sectional view of an automobile weather strip, FIG. 5 is a perspective view showing the form of an intermediate molded product of the weather strip shown in FIG. 4, and FIG. 6 is a view showing the form of an intermediate molded product having a cutout. A perspective view, FIG. 7 is an explanatory diagram showing the relationship between the intermediate molded product in FIG. 6 and the blade, FIG. 8 is a front view of the extrusion head, and FIG. 9 is an enlarged perspective view of the main part of the cutter blade in FIG. 8. 10 are cross-sectional views taken along line BB in FIG. 9. DESCRIPTION OF SYMBOLS 1... Cutter, 3... Blade, 4... Hollow shaft, 6... Cutting edge, 32... Seal lip, 34... Intermediate molded product as an extrusion molded product, 39... Resection Department, 40
...Extrusion head, 41 - Mouthpiece. 1-・Kazuta 3-"7)-de diagram fig. 5 1 J4 (JU) fig. 4 fig. fig.

Claims (1)

[Claims] (1) By extruding the molding material from the mouthpiece of the extrusion head to extrude an extrusion molded product with a predetermined cross-sectional shape, and by moving a cutter placed on the front side of the mouthpiece forward and backward in a plane parallel to the front side of the mouthpiece. In an apparatus for cutting a part of an extruded product immediately after molding, the blade of the cutter is formed to have a streamlined cross section, and the blade is oscillated about an axis perpendicular to the forward and backward movement direction of the cutter. An extrusion molded product manufacturing device characterized by being configured to be capable of dynamic displacement.